System and / or method for providing EPDCCH in a multi-carrier-based and / or pseudo-matching network

Abstract

To provide an ePDCCH.SOLUTION: A WTRU is configured to receive a configuration for monitoring an ePDCCH resource to monitor the ePDCCH resource on a particular subframe. The WTRU may derive an aggregation level for a subframe associated with an aggregation level number NAL to transmit or monitor an ePDCCH using the aggregation level. The WTRU may receive a reference signal and determine the type of the reference signal. The WTRU may perform demodulation of PDSCH or ePDCCH using a demodulation timing based on the determined type. The ePDCCH or PDSCH may also be monitored or received by identifying a demodulation reference timing implicitly based on a location of one or more ePDCCH resources where the WTRU may receive DCI.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] Cross-reference of related applications This application builds upon the contents of the following U.S. Patent Provisional Application No. 61 / 591,508, filed on 27 January 2012; the U.S. Patent Provisional Application No. 61 / 612,834, filed on 19 March 2012; the U.S. Patent Provisional Application No. 61 / 688,164, filed on 9 May 2012; and the U.S. Patent Provisional Application No. 61 / 644,97, filed on 9 May 2012, the contents of which are incorporated herein by reference. This application asserts the benefits of Specification No. 2, U.S. Provisional Patent Application No. 61 / 678,612 filed on August 1, 2012, U.S. Provisional Patent Application No. 61 / 706,119 filed on September 26, 2012, U.S. Provisional Patent Application No. 61 / 720,646 filed on October 31, 2012, and U.S. Provisional Patent Application No. 61 / 753,279 filed on January 16, 2013. [Background technology]

[0002] Current communication systems (e.g., LTE / LTE-Advanced systems) may have multiple antennas, multiple component carriers, and / or quasi-collated antenna ports to support transmission. Such multiple antennas, multiple component carriers, and / or quasi-collated antenna ports may be provided for a variety of purposes, including improving peak system throughput, expanding cell coverage, supporting higher Doppler, and so on. Unfortunately, such communication systems may be configured in a way that is not suitable for supporting quasi-collated antenna ports, such as focusing on a single component carrier (e.g., multiple component carriers and / or multiple antennas) and / or limiting the performance of multi-carrier systems, and / or not being properly designed to avoid errors within frames and / or subframes (e.g., special subframes), resulting in tight PDSCH and / or CSI reporting processing times, inability to make proper PUCCH resource allocations, inability to provide PDCCH instructions during the duration of the configuration and / or reference symbol in which quasi-collation with the antenna port can occur, and insufficient time for use in ePDCCH and / or its decoding. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] section 7.1.7.2.1 of 3GPP TS 36.213 “Physical Layer Procedures”, V10.1.0, 2011-03 [Overview of the Initiative] [Means for solving the problem]

[0004] Systems, methods, and means for implementing ePDCCH in a multi-carrier communication system may be disclosed. For example, a UE or WTRU may receive a configuration for monitoring ePDCCH resources. Based on such a configuration, the UE or WTRU may be configured to monitor ePDCCH resources in a particular subframe. The WTRU can then monitor the ePDCCH resources in the subframe. In an exemplary embodiment, the subframe does not have to be a special subframe, the configuration is received via higher layer signaling, the configuration may include one or more PRB sets for monitoring on ePDCCH resources, the PRB set may include a set of eCCEs including eREGs, and further perform activities such as monitoring PDCCH resources in different subframes, demodulating ePDCCH resources, and similar activities.

[0005] Systems, methods, and means for providing ePDCCH based on aggregation levels may also be disclosed. For example, a UE or WTRU can derive an aggregation level (e.g., an eCCE aggregation level) for a subframe. The UE or WTRU has a number of aggregation levels N for its subframes. AL Based on this, such aggregation levels can be derived, and in one embodiment, N AL n can be a positive integer. UE or WTRU is N for its subframe. AL ePDCCH can be sent or monitored according to or using the aggregation level associated with it. For example, if the search space is {1, 2, 4, 8}, then N AL If the value is 2, the UE or WTRU can be monitored according to {2, 4, 8, 16}.

[0006] Systems, methods, and means for receiving or monitoring an ePDCCH or PDSCH may be further disclosed herein. For example, a UE or WTRU may receive a reference signal. The UE or WTRU may then determine the type of the received reference signal. Based on its type, the UE or WTRU may perform demodulation of the PDSCH or ePDCCH using demodulation timing. For example, if the reference signal is a channel status information reference signal (CSI-RS), PDSCH demodulation may be performed using demodulation reference timing based on fast Fourier transform (FFT) timing and channel estimation coefficients associated with the CSI-RS. In additional embodiments, an ePDCCH or PDSCH may be monitored by implicitly identifying demodulation reference timing based on the location of one or more ePDCCH resources from which the UE or WTRU can receive downlink control information (DCI). [Brief explanation of the drawing]

[0007] The details of this invention can be better understood by reading the following description in conjunction with, for example, the accompanying drawings. [Figure 1A] This is a diagram of a communication system as an example of one or more of the disclosed embodiments that may be implemented. [Figure 1B] Figure 1A is a system diagram of a wireless transmit / receive unit (WTRU) as an example of one that may be used in the communication system illustrated. [Figure 1C] Figure 1A is a system diagram of an example wireless access network and an example core network that may be used within the communication system illustrated. [Figure 1D] Figure 1A shows system diagrams of a wireless access network and a core network, as examples, as alternative examples of networks that may be used within the communication system illustrated. [Figure 1E] Figure 1A shows system diagrams of a wireless access network and a core network, as examples, as alternative examples of networks that may be used within the communication system illustrated. [Figure 2]This figure shows one embodiment as an example of a WTRU or UE-specific precoded DM-RS. [Figure 3] This figure shows one embodiment as an example of a cell-specific RS that is not precoded. [Figure 4] This figure shows one embodiment as an example of a WTRU or UE-specific DM-RS relative to a normal CP (e.g., port 5). [Figure 5] This figure shows an embodiment of a CRS structure as an example based on the number of antenna ports. [Figure 6] This figure shows one embodiment of an example DM-RS pattern that can support eight layers. [Figure 7] This figure shows one embodiment of an example of a reusable CSI-RS pattern based on the number of ports. [Figure 8] This figure shows one embodiment as an example of a positioning architecture. [Figure 9] This figure shows one embodiment as an example of REG definition within the downlink control channel region using 2Tx CRS. [Figure 10] This figure shows one embodiment as an example of REG definition within the downlink control channel region using 4Tx CRS. [Figure 11] This figure shows one embodiment as an example of PCI-based PCFICH REG allocation. [Figure 12] This figure shows one embodiment as an example of PCI-based PCFICH and PHICH REG allocation. [Figure 13] This figure shows one embodiment as an example of ePDCCH multiplexing with PDSCH (e.g., FDM multiplexing). [Figure 14] This figure shows one embodiment as an example of mapping PUCCH to physical resource blocks. [Figure 15] This figure shows one embodiment as an example of a collision between DM-RS and PRS. [Figure 16]This figure shows one embodiment as an example of ePDCCH resource allocation within a subframe. [Figure 17] This is a diagram illustrating one embodiment of a carrier aggregation system with different TDD UL-DL configurations. [Figure 18] This figure shows one embodiment of a CCE aggregation across multiple carriers in distributed resource allocation. [Figure 19] This figure shows one embodiment of an example of a PRB pair that can be used for ePDCCH transmission based on the number of antenna ports (for example, ports 7-10 and 7-8, respectively). [Figure 20] This figure shows one embodiment as an example of eCCE-eREG mapping in ePDCCH based on centralized and / or distributed allocation. [Figure 21] This figure shows one embodiment of an example of eCCE-eREG mapping using continuous allocation. [Figure 22] This figure shows one embodiment as an example of a block interleaver. [Figure 23] This figure shows one embodiment of a hybrid allocation example using a block interleaver. [Figure 24] This figure shows one embodiment as an example of the coexistence of centralized and / or distributed eCCEs. [Figure 25] This figure shows one embodiment as an example of antenna port mapping for eREG and eCCE. [Figure 26] This figure shows one embodiment of a common search space definition in the legacy PDCCH region within PCell. [Modes for carrying out the invention]

[0008] Next, a detailed description of exemplary embodiments will be given with reference to the figures. However, while embodiments herein can be described in relation to exemplary embodiments, they should not be limited thereto, and other embodiments can be used, or modifications and additions can be made to embodiments described to perform the same or similar functions as disclosed without departing from the invention. In addition, figures may be illustrative to show call flows. It will be understood that other embodiments can also be used. The order of flows can be changed. Also, flows may be omitted if they are not implemented, and additional flows may be added if any.

[0009] Systems and / or methods for achieving efficient downlink control channel design (e.g., enhanced downlink control channels) in multi-carrier-based wireless networks (e.g., the networks described in Figures 1A-1E) may be disclosed. For example, such systems and / or methods can achieve and / or utilize centralized and / or distributed resource allocation in multi-carrier systems, which includes, for example, the ability to achieve distributed resource allocation of multiple component carriers. In addition, PDSCH and / or CSI feedback processing time relaxation, including flexible PDSCH processing time adaptation based on multi-component carrier reception combined with ePDCCH and / or flexible CSI reporting time adaptation based on reporting bandwidth, the number of component carriers, and the like, may be achieved and / or used in such systems and / or methods. In one embodiment, such a system and / or method may further provide and / or use relationships between ePDCCH and legacy uplink control signaling, including cross-carrier scheduling and / or new assignment of the physical and / or logical addresses (e.g., CCE index) of the ePDCCH with respect to uplink control channel relationships. TDD-specific embodiments of such a system and / or method, including the use of ePDCCH in special subframes and / or TDD interband, may also be provided and / or used. According to one exemplary embodiment, a PDCCH fallback transmit mode may be provided and / or used for such a system and / or method, where the operation of the UE or WTRU of a PDCCH receive is within an ambiguity period and an RRC-configured PDCCH configuration between legacy PDCCH and ePDCCH is used.

[0010] In addition, such systems and / or methods may provide and / or use variable eREG and / or eCCE definitions, for example, fully FDM-based eREG definitions. Such systems and / or methods may further provide and / or use eCCE-eREG mapping based on ePDCCH transmission modes, interleaver designs using variable eREG and / or eCCE definitions, adaptive eREG-eCCE mapping (e.g., a variable number of eREGs per eCCE due to reference signal overhead in subframes), and similar. In one embodiment, antenna port associations to eREG and / or eCCEs, including location and / or aggregation level-based antenna port mapping and / or PRG size definitions for PRB bundling, may be provided and / or used in such systems and / or methods. For example, ePDCCH search space designs, including common search spaces and / or WTRU or UE-specific spatial searches, TBS constraints based on TA and / or CSI feedback requirements, and / or PUCCH assignments based on ePDCCH using multiple downlink component carriers, are also provided and / or used with such systems and / or methods.

[0011] According to one embodiment, such a system and / or method may provide and / or use antenna port associations with WTRU or UE-specific configurations, including a combination of RE position-based mapping and / or WTRU or UE-specific configurations, and antenna port mapping rules based on a common search space and a WTRU or UE-specific search space in distributed transmission. In one embodiment, collision handling between ePDCCH resources and legacy signals other than PDSCH, including rate matching and / or puncturing rules, may be provided and / or used in such a system and / or method. In addition, adaptive eREG-eCCE mapping, mapping rules based on subframe characteristics, and the like may be provided and / or used. In an additional embodiment, TBS limiting in TDD mode by HARQ-ACK timing may be provided and / or used.

[0012] Such systems and / or methods may further provide and / or use ePDCCH resources. For example, multiple ePDCCH resource sets may be provided and / or used, with a variable resource size per set, determined by the system bandwidth, which includes a downlink control information (DCI) format determined by the ePDCCH candidate, an ePDCCH resource set determined by a hash function, and / or an ePCFICH instruction for the number of ePDCCH resource sets.

[0013] PUCCH(A / N) resource allocation for ePDCCH, including support for MU-MIMO, may also be provided and / or used (for example, in such systems and / or methods).

[0014] In one embodiment, such a system and / or method may also provide PRS collision handling techniques that include the steps of broadcasting PRS configuration information and / or causing WTRU or UE action when an ePDCCH resource may conflict with the PRS.

[0015] Multiple ePDCCH resource sets for a multi-carrier system may be further provided and / or defined by such system and / or method. For example, DM-RS sequences may be defined. In one such embodiment, a DM-RS sequence generator (XID) may be configured, used, and / or defined for each ePDCCH set or for each ePDCCH set. In addition, if a WTRU or UE can receive a PDSCH associated with an ePDCCH, the same XID received from the ePDCCH may be used to demodulate the PDSCH. In additional embodiments, PUCCH resource allocation by multiple ePDCCH resource sets may be provided and / or used, and / or a search space definition for centralized transmissions may be provided and / or used, including ePDCCH transmission-specific hash function definitions and / or ePDCCH transmission-specific eCCE indexing, such as indexing of different eCCEs by or based on aggregation levels. eREG-eCCE mappings may also be provided and / or used. For example, cell-specific eREG-eCCE mappings based on centralized and distributed transmissions may be provided and / or used. In one embodiment, supported transmission modes associated with an ePDCCH may also be provided and / or defined, for example, including a subset of transmission modes supported by an ePDCCH and / or supported ePDCCH types (e.g., centralized and distributed) which may differ (e.g., according to the transmission scheme).

[0016] In addition, such systems and / or methods can provide an ePDCCH with a WTRU or UE-specific search space (e.g., an associated equation) and hash function. For example, search space equations and / or hash functions for centralized and distributed ePDCCHs with multiple sets of ePDCCHs can be provided and / or used.

[0017] Such systems and / or methods may further provide an ePDCCH common search space, including eREG / eCCE definitions for the common search space, start symbols (e.g., those associated with them), resource definitions / configurations, and / or support for resource overlap between the UE-specific search space and the common search space.

[0018] Systems and methods for issuing demodulation reference timing instructions may be disclosed. For example, single demodulation reference timing support and multiple demodulation reference timing support, such as resource-specific demodulation reference timing, and instructions for demodulation reference timing (e.g., demodulation reference timing instructions) may be provided as described herein.

[0019] Figure 1A shows a communication system 100 as an example in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, and broadcast to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), quadrature FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like.

[0020] As shown in Figure 1A, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, and / or 102d (which may be commonly referred to as WTRU 102 or collectively as such), radio access networks (RANs) 103 / 104 / 105, core networks 106 / 107 / 109, public switched telephone network (PSTN) 108, the internet 110, and other networks 112, but the disclosed embodiments are understood to intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d can be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRU102a, 102b, 102c, and 102d can be configured to transmit and / or receive wireless signals and may include user equipment (UEs), mobile stations, fixed or mobile subscriber units, pagers, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, consumer electronics, and the like.

[0021] The communication system 100 may also include base stations 114a and 114b. Each of the base stations 114a and 114b can be any type of device configured to wirelessly interface with at least one WTRU from among WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as the core networks 106 / 107 / 109, the Internet 110, and / or network 112. For example, base stations 114a and 114b could be transceiver base stations (BTS), node B, eNodeB, home node B, home eNodeB, site controllers, access points (APs), wireless routers, and similar. While base stations 114a and 114b may each be represented as single elements, it will be understood that base stations 114a and 114b can include any number of interconnected base stations and / or network elements.

[0022] Base station 114a may be part of RAN 103 / 104 / 105, which may also include other base stations and / or network elements (not shown), such as a base station control unit (BSC), a radio network controller (RNC), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals within a specific geographic area, which may also be referred to as a cell (not shown). A cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In another embodiment, base station 114a may employ multi-input multi-output (MIMO) technology, and therefore multiple transceivers may be available for each sector of the cell.

[0023] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interfaces 115 / 116 / 117, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interfaces 115 / 116 / 117 can be installed using any suitable radio access technology (RAT).

[0024] More specifically, as described above, the communication system 100 can be a multiple access system and can employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and similar. For example, base stations 114a in RAN 103 / 104 / 105, and WTRU 102a, 102b, 102c can implement radio technologies such as Universal Mobile Communications System (UMTS) Terrestrial Radio Access (UTRA), which can install air interfaces 115 / 116 / 117 using broadband CDMA (WCDMA®). WCDMA can be equipped with communication protocols such as High Speed ​​Packet Access (HSPA) and / or Advanced HSPA (HSPA+). HSPA can be equipped with High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0025] In another embodiment, base stations 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as Advanced UMTS Terrestrial Radio Access (E-UTRA), which can install air interfaces 115 / 116 / 117 using Long-Term Evolution (LTE) and / or LTE-Advanced (LTE-A).

[0026] In other embodiments, base stations 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM®), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and similar technologies.

[0027] The base station 114b in Figure 1A can be, for example, a wireless router, home node B, home eNode B, or access point, and can utilize a suitable RAT to facilitate wireless connectivity in localized areas such as offices, homes, automobiles, campuses, and similar locations. In one embodiment, the base station 114b and WTRU 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station 114b and WTRU 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and WTRU 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in Figure 1A, the base station 114b can have a direct connection to the internet 110. Therefore, base station 114b no longer needs to access the internet 110 via the core network 106 / 107 / 109.

[0028] RAN103 / 104 / 105 may be assumed to be communicating with core network 106 / 107 / 109, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more WTRUs among WTRU102a, 102b, 102c, and 102d. For example, core network 106 / 107 / 109 may provide call control, billing services, mobile location services, prepaid calls, internet connectivity, video distribution, etc., and / or implement high-level security features such as user authentication. Although not shown in Figure 1A, RAN103 / 104 / 105 and / or core network 106 / 107 / 109 may communicate directly or indirectly with other RANs employing the same RAT as RAN103 / 104 / 105, or a different RAT. For example, in addition to connecting to RANs 103 / 104 / 105, which may be using E-UTRA radio technology, core networks 106 / 107 / 109 may also be communicating with another RAN (not shown) that employs GSM radio technology.

[0029] Core networks 106 / 107 / 109 may also function as gateways for WTRUs 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing simple legacy telephone services (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols, such as the Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Protocol (IP), which are part of the TCP / IP Internet Protocol suite. Network 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another core network connected to one or more RANs, which may employ the same RAT as RAN 103 / 104 / 105, or a different RAT.

[0030] Some or all of the WTRUs 102a, 102b, 102c, and 102d within the communication system 100 have multi-mode capabilities, meaning that WTRUs 102a, 102b, 102c, and 102d can include multiple transceivers for communicating with different wireless networks on different wireless links. For example, WTRU 102c, shown in Figure 1A, may be configured to communicate with base station 114a, which may employ cellular-based radio technology, and base station 114b, which may employ IEEE 802 radio technology.

[0031] Figure 1B is a system diagram of an example WTRU102. As shown in Figure 1B, the WTRU102 may comprise a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and other peripherals 138. It will be understood that the WTRU102 may include partial combinations of the aforementioned elements while maintaining consistency with one embodiment. Furthermore, in the embodiments, base stations 114a and 114b, and / or, but not limited to, nodes that base stations 114a and 114b may represent, such as a transceiver station (BTS), node B, site controller, access point (AP), home node B, advanced home node B (eNodeB), home advanced node B (HeNB), home advanced node B gateway, and proxy node, are shown in Figure 1B and are intended to include some or all of the elements described herein.

[0032] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 can perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120, which can be coupled to a transmit / receive element 122. Figure 1B shows the processor 118 and transceiver 120 as separate components, but please note that the processor 118 and transceiver 120 can be integrated together in an electronic package or chip.

[0033] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) on the air interface 115 / 116 / 117. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be a radiator / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and receive both RF and optical signals. It should be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0034] In addition, although Figure 1B shows the transmit / receive element 122 as a single element, the WTRU 102 can have any number of transmit / receive elements 122. More specifically, the WTRU 102 can employ MIMO technology. Therefore, in one embodiment, the WTRU 102 can have two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interfaces 115 / 116 / 117.

[0035] The transceiver 120 may be configured to modulate signals that may be transmitted by the transmit / receive element 122 and to demodulate signals that may be received by the transmit / receive element 122. As described above, the WTRU 102 can have multimode functionality. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11.

[0036] The processor 118 of the WTRU102 is coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from there. The processor 118 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 can access information in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and can store data in such memory. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a subscriber identification module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In another embodiment, the processor 118 can access information located in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown), and store the data in such memory.

[0037] The processor 118 may be configured to receive power from the power supply 134, distribute that power to other components within the WTRU 102, and / or control them. The power supply 134 can be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may be one or more dry cell batteries (e.g., nickel-cadmium (NiCd) batteries, nickel-zinc (NiZn) batteries, nickel-metal hydride (NiMH) batteries, lithium-ion (Li-ion) batteries, etc.), solar cells, fuel cells, and similar devices.

[0038] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, the WTRU 102 can determine its position based on the timing of receiving location information from base stations (e.g., base stations 114a, 114b) on air interfaces 115 / 116 / 117 and / or receiving signals from two or more nearby base stations. It should be understood that the WTRU 102 may acquire location information using any preferred location determination method while maintaining consistency with one embodiment.

[0039] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos or videos), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, and the like.

[0040] Figure 1C is a system diagram of RAN 103 and core network 106 according to one embodiment. As described above, RAN 103 can employ UTRA radio technology to communicate with WTRU 102a, 102b, and 102c over air interface 115. RAN 103 can also communicate with core network 106. As shown in Figure 1C, RAN 103 may comprise nodes B140a, 140b, and 140c, each comprising one or more transceivers for communication with WTRU 102a, 102b, and 102c over air interface 115. Nodes B140a, 140b, and 140c may each be associated with a specific cell (not shown) within RAN 103. RAN 103 may also comprise RNC 142a and 142b. It will be understood that RAN 103 may comprise any number of nodes B and RNC while maintaining consistency with one embodiment.

[0041] As shown in Figure 1C, nodes B140a and B140b may be communicating with RNC142a. In addition, node B140c may be communicating with RNC142b. Nodes B140a, B140b, and B140c can communicate with each other via the Iur interface. RNC142a and B142b can also communicate with each other via the Iur interface. Each of RNC142a and B142b may be configured to control each of the connected nodes B140a, B140b, and B140c. In addition, each of RNC142a and B142b may be configured to perform or support other functions such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, data encryption, and the like.

[0042] The core network 106 shown in Figure 1C may comprise a media gateway (MGW) 144, a mobile communications switching center (MSC) 146, a service GPRS support node (SGSN) 148, and / or a gateway GPRS support node (GGSN) 150. While each of the aforementioned elements may be shown as part of the core network 106, it will be understood that any one of these elements may be owned and / or operated by an entity other than the core network operator.

[0043] RNC142a in RAN103 can connect to MSC146 in core network 106 via the IuCS interface. MSC146 can connect to MGW144. MSC146 and MGW144 enable WTRU102a, 102b, and 102c to access circuit-switched networks such as PSTN108, facilitating smooth communication between WTRU102a, 102b, and 102c and communication devices using conventional terrestrial communication lines.

[0044] RNC142a in RAN103 can also connect to SGSN148 in core network 106 via the IuPS interface. SGSN148 can connect to GGSN150. SGSN148 and GGSN150 may enable WTRU102a, 102b, and 102c to access a packet-switched network, such as the Internet 110, to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0045] As noted above, the core network 106 may also connect to network 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0046] Figure 1D is a system diagram of RAN104 and core network 107 according to one embodiment. As described above, RAN104 can employ E-UTRA radio technology for WTRU102a, 102b, and 102c communication over air interface 116. RAN104 can also communicate with core network 107.

[0047] RAN104 may comprise eNodeB160a, 160b, and 160c, but RAN104 may comprise any number of eNodeB while maintaining consistency with one embodiment. Each eNode-B160a, 160b, and 160c may comprise one or more transceivers for communicating with WTRU102a, 102b, and 102c over the air interface 116. In one embodiment, eNodeB160a, 160b, and 160c can implement MIMO technology. For example, eNodeB160a can use multiple antennas to transmit wireless signals to and receive wireless signals from WTRU102a.

[0048] Each of the eNodeB160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling on uplink and / or downlink, and similar functions. As shown in Figure 1D, the eNodeB160a, 160b, and 160c can communicate with each other over the X2 interface.

[0049] The core network 107 shown in Figure 1D may include a mobility management entity (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. While each of the aforementioned elements may be shown as part of the core network 107, it will be understood that any one of these elements may be owned and / or operated by an entity other than the core network operator.

[0050] The MME162 can be connected to each of the eNode-B160a, 160b, and 160c within RAN104 via the S1 interface and used as a control node. For example, the MME162 may be responsible for user authentication of WTRU102a, 102b, and 102c, bearer activation / deactivation, and selection of a specific serving gateway during the initial attachment of WTRU102a, 102b, 102c, and similar devices. The MME162 may also have control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM or WCDMA.

[0051] The serving gateway 164 can be connected to each of the eNode-B160a, 160b, and 160c in RAN104 via the S1 interface. The serving gateway 164 can generally perform route selection and forwarding of user data packets to and from WTRU102a, 102b, and 102c. The serving gateway 164 can also perform other functions such as anchoring the user plane during eNodeB handovers, triggering paging when downlink data becomes available for WTRU102a, 102b, and 102c, managing and storing the context of WTRU102a, 102b, and 102c, and similar operations.

[0052] The serving gateway 164 can also connect to the PDN gateway 166, which allows WTRU102a, 102b, and 102c to access packet-switched networks such as the Internet 110, facilitating smooth communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0053] The core network 107 can facilitate communication with other networks. For example, the core network 107 enables WTRU102a, 102b, and 102c to access circuit-switched networks such as PSTN108, facilitating communication between WTRU102a, 102b, and 102c and communication devices using conventional terrestrial communication lines. For example, the core network 107 may have, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between the core network 107 and PSTN108. In addition, the core network 107 allows WTRU102a, 102b, and 102c to access network 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0054] Figure 1E is a system diagram of RAN105 and core network 109 according to one embodiment. RAN105 may be an access service network (ASN) employing IEEE 802.16 wireless technology for WTRU102a, 102b, and 102c communication over air interface 117. As will be further described below, communication links between different functional entities of WTRU102a, 102b, 102c, RAN105, and core network 109 can be defined as reference points.

[0055] As shown in Figure 1E, RAN105 may comprise base stations 180a, 180b, 180c and an ASN gateway 182, but it should be understood that RAN105 may comprise any number of base stations and ASN gateways while maintaining consistency with one embodiment. Each base station 180a, 180b, and 180c is associated with a specific cell (not shown) within RAN105 and may comprise one or more transceivers for communicating with WTRU102a, 102b, and 102c on the air interface 117. In one embodiment, base stations 180a, 180b, and 180c may implement MIMO technology. For example, base station 180a may use multiple antennas to transmit wireless signals to and receive wireless signals from WTRU102a. Base stations 180a, 180b, and 180c may also include mobility management functions such as triggering handoffs, establishing tunnels, managing radio resources, classifying traffic, enforcing quality of service (QoS) policies, and similar functions. The ASN gateway 182 may be used as a traffic aggregation point and may be responsible for paging, caching subscriber profiles, routing to the core network 109, and similar functions.

[0056] The air interface 117 between WTRU102a, 102b, 102c and RAN105 may be defined as an R1 reference point implementing the IEEE 802.16 specification. In addition, each of WTRU102a, 102b, and 102c can establish a logical interface (not shown) with the core network 109. The logical interfaces between WTRU102a, 102b, 102c and the core network 109 may be defined as an R2 reference point that can be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0057] The communication links between base stations 180a, 180b, and 180c can be defined as R8 reference points, each equipped with protocols for facilitating WTRU handover and data transfer between base stations. The communication links between base stations 180a, 180b, and 180c and the ASN gateway 182 can be defined as R6 reference points. R6 reference points may be equipped with protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, and 102c.

[0058] As shown in Figure 1E, RAN 105 can be connected to the core network 109. The communication link between RAN 105 and the core network 109 may be defined, for example, as an R3 reference point with protocols that facilitate data transfer and mobility management functions. The core network 109 may comprise a Mobile IP Home Agent (MIP-HA) 184, an Authentication / Authorization / Accounting (AAA) server 186, and a gateway 188. While each of the aforementioned elements may be shown as part of the core network 109, it will be understood that any one of these elements may be owned and / or operated by an entity other than the core network operator.

[0059] The MIP-HA is responsible for IP address management and can enable WTRU102a, 102b, and 102c to roam between different ASNs and / or different core networks. The MIP-HA184 may enable WTRU102a, 102b, and 102c to access packet-switched networks, such as the Internet 110, to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. The AAA server 186 may be responsible for user authentication and support for user services. The gateway 188 can facilitate interaction with other networks. For example, the gateway 188 may enable WTRU102a, 102b, and 102c to access circuit-switched networks, such as the PSTN 108, to facilitate communication between WTRU102a, 102b, and 102c and communication devices using conventional terrestrial communication lines. In addition, gateway 188 enables WTRUs 102a, 102b, and 102c to access network 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0060] Although not shown in Figure 1E, it will be understood that RAN105 may be connected to other ASNs, and core network 109 may be connected to other core networks. The communication link between RAN105 and other ASNs may be defined as an R4 reference point, which may include protocols for coordinating the mobility of WTRU102a, 102b, and 102c between RAN105 and other ASNs. The communication link between core network 109 and other core networks may be defined as an R5 reference point, which may include protocols for facilitating communication between the home core network and the visited core network.

[0061] According to one embodiment as an example, coordinated and / or multi-antenna transmission can be performed in a communication system (e.g., an LTE / LTE-Advanced system) such as the communication system 100 described above with respect to Figures 1A-1E. In some embodiments, such coordinated transmission can be implemented and / or used so that PDSCH transmission to a WTRU or UE (e.g., an LTE-A WTRU or UE) can be dynamically changed between transmission points without performing cell selection / reselection procedures. WTRU or UE-specific RS-based downlink control channel transmission can also be implemented and / or used, for example, to enhance the performance of PDCCH.

[0062] In addition, such multi-antenna transmissions can be implemented and / or used for a variety of purposes, including improving peak system throughput, expanding cell coverage, and supporting high Doppler. For example, single-user multi-input multi-output (SU-MIMO) can be used in such communication systems to increase the peak and / or average throughput of the user equipment (UE) or WTRU. In addition, multi-user MIMO can be used in such communication systems to improve peak and / or average system throughput by leveraging multi-user diversity gain. Table 1 shows MIMO capabilities as examples that can be used in wireless communication systems to improve throughput, diversity gain, and similar.

[0063] [Table 1]

[0064] To support MIMO performance (e.g., due to or based on the WTRU or UE channel environment), up to nine transmit modes are employed, for example. Such transmit modes include transmit diversity mode, open-loop space multiplexing mode, closed-loop space multiplexing mode, and similar modes. In addition, MIMO link adaptation may be used and / or implemented. In some embodiments, the WTRU or UE may report channel status information (CSI) for multiple transmit antenna ports to enable or facilitate such MIMO link adaptation.

[0065] For example, a reference signal may be provided and / or used together with, for example, a CSI. In one embodiment, the reference signal may be provided or classified as a WTRU or UE-specific reference signal (WTRU or UE-RS) and / or a cell-specific reference signal (CRS). According to one embodiment, the WTRU or UE-RS may be used for a particular WTRU or UE so that the RS is transmitted to a resource to which the WTRU or UE is allocated. In addition, in one embodiment, the CRS may be a cell-specific reference signal that can be shared by each of the UEs in the cell so that the RS is transmitted over a wideband.

[0066] By use, or based on use, a reference signal (RS) can be differentiated into, for example, a demodulated reference signal (DM-RS) and / or a channel state information reference signal (CSI-RS). A DM-RS can be used for a specific WTRU or UE, and the RS may be precoded to take advantage of beamforming gain. In one embodiment, a WTRU or UE-specific DM-RS cannot be shared with other UEs in the cell. As such, the DM-RS may be transmitted using time and / or frequency resources allocated to the WTRU or UE. In addition, the DM-RS may be restricted to use in demodulation.

[0067] Figure 2 shows one embodiment as an example of providing WTRU or UE-specific precoded DM-RS. As shown in Figure 2, when precoded DM-RS can be employed, the RS is precoded using the precode used for data symbols, and a number of RS sequences K corresponding to the number of layers may be transmitted. In one embodiment, K is the number of physical antenna ports N. T The following may apply. In addition, the K streams in Figure 2 may be allocated to a WTRU or UE, or shared by multiple UEs. If multiple UEs can share the K streams, concurrently scheduled UEs can share the same time / frequency resources simultaneously.

[0068] As described above, a cell-specific reference signal (CRS) may be provided and / or used. According to one exemplary embodiment, the CRS may be defined for a UE in the cell and used for demodulation and / or measurement. In addition, in the exemplary embodiment, the CRS may be shared by the UE. In such embodiments (for example, since the CRS may be shared by the UE), an unprecoded RS may be used and / or employed, for example, to maintain uniform cell coverage. A precoded RS may have different cell coverage depending on the direction and / or due to beamforming effects. Figure 3 shows one exemplary embodiment of a MIMO transmitter that may be used for unprecoded CRS transmission as described herein.

[0069] In addition, in exemplary embodiments, antenna virtualization may be implemented and / or used. For example, antenna virtualization is useful when the number of physical antenna ports may differ from the number of logical antenna ports (e.g., CRS and / or uncoded CRS transmission as shown in Figure 3). RS sequences may also be transmitted to antenna ports regardless of the number of streams.

[0070] According to exemplary embodiments, different structures for DM-RS and / or CRS can be realized and / or used. Figure 4 shows an exemplary embodiment of a DM-RS (e.g., antenna port-5) structure that can be used (e.g., in an LTE system) to support non-codebook-based transmission. In one embodiment, the structure shown in Figure 4 can be used in an eNB, for example, when antenna port-5 may be limited to supporting single-layer transmission. In addition, antenna port-5 shown in Figure 4 is transmitted together with CRS, and as such, the RS overhead may increase (e.g., overall).

[0071] Figure 5 shows an embodiment as an example of a CRS structure depending on or based on the number of antenna ports. The CRS patterns for each antenna port (e.g., shown in Figure 5) may be mutually orthogonal in the time and / or frequency domain. As shown in Figure 5, R0 and R1 may represent the CRS for antenna port 0 and antenna port 1, respectively. In one embodiment, to avoid interference between CRS antenna ports, data REs that may be placed in REs from which CRS antenna ports can transmit may be muted.

[0072] According to an exemplary embodiment, a predefined sequence (e.g., pseudo-random (PN), m-sequence, and similar) can be multiplied by a downlink RS that can minimize inter-cell interference and / or improve the channel estimation accuracy associated with the CRS. The PN sequence is applied at the OFDM symbol level within a subframe, and this sequence may be defined according to the cell ID, subframe number, OFDM symbol location, and similar. For example, the number of CRS antenna ports may be 2 in an OFDM symbol, for example, which may contain one CRS per PRB, and the number of PRBs in a communication system such as an LTE system can vary from 6 to 110. In such an embodiment, the total number of CRSs for antenna ports in an OFDM symbol that may contain RS is 2xN RB This means that the sequence length is 2xN RB This implies that it may be so. In addition, in such embodiments, N RB represents the number of RBs corresponding to the bandwidth, and the sequence can be a binary or complex number. The sequence r(m) is,

[0073]

number

[0074] A complex number sequence can be given as, however,

[0075]

number

[0076] This often represents the number of RBs corresponding to the maximum bandwidth in a communication system such as an LTE system.

[0077]

number

[0078] It may be assumed that is 110. In addition, c can represent a PN sequence of length -31, which can be defined in Gold-sequences. If a DM-RS can be constructed, the formula

[0079]

number

[0080] However,

[0081]

number

[0082] This can represent the number of RBs assigned to a particular WTRU or UE. The sequence length may vary depending on the number of RBs assigned to the WTRU or UE.

[0083] In one embodiment, a reference signal (RS) structure can also be implemented (e.g., in 3GPP® LTE-A). For example, DM-RS based downlink transmission may be used to reduce overall RS overhead (e.g., in communication systems such as LTE-A). In addition, CRS-based downlink transmission can transmit RS sequences for physical antenna ports. As such, DM-RS based downlink transmission can reduce RS overhead by considering that the number of RSs sent or used for DM-RS may be equal to the number of layers. In addition, according to one embodiment, the number of layers may be less than or equal to the number of physical antenna ports. Figure 6 shows one embodiment as an example of a DM-RS pattern in a PRB for subframes that may be sent and / or used (e.g., a DM-RS pattern supporting up to 8 layers).

[0084] In some embodiments, two CDM groups may be used, for example, to multiplex up to four layers within each CDM group, and up to eight layers may be multiplexed in this pattern. A 4x4 Walsh diffusion pattern may also be used for the CDM multiplexing of each CDM group.

[0085] In addition, since DM-RS can be used for demodulation performance (for example, it may be limited to being used for demodulation performance), CSI-RS, which is sparse with respect to time and / or frequency, may be provided, for example, for measurement. CSI-RS may be transmitted within the PDSCH area with duty cycles such as {5, 10, 20, 40, 80} ms. In addition, up to 20 CSI-RS patterns may be available within a subframe for reuse. Figure 7 shows one embodiment as an example of a CSI-RS pattern that can be reused based on the number of ports (for example, up to 20 CSI-RS patterns can be reused). In Figure 7, the same pattern or shading, which contains or is associated with the corresponding number of TXs, may represent the same set of REs for a CSI-RS configuration.

[0086] Observed Time Difference of Arrival (OTDOA) may also be provided and / or used for positioning in communication systems, such as LTE systems. In OTDOA positioning, a WTRU or UE may receive one or more signals from a reference cell and / or one or more additional cells, e.g., neighboring cells, measure the observed time difference of these signals (e.g., between each additional or neighboring cell and the reference cell), and / or report such measurements, information, or signals to the network. Based on the cell locations, the timing differences between them which may be fixed, and / or other information, the network may derive the position of the WTRU or UE by means such as trilateration or triangulation (e.g., assuming the WTRU or UE can measure at least three cells), and / or by other methods or techniques that can provide arrangement and / or location. The reference cell may or may not be a serving cell, e.g., the serving cell of the WTRU or UE. For example, the reference cell may be a serving cell of a WTRU or UE, for instance, if the WTRU or UE may have one serving cell, for example, in the absence of carrier aggregation (CA). In another example, the reference cell may be a serving cell such as a primary cell, PCell, etc., for example, in the presence of carrier aggregation. In one embodiment, the arrival time difference may be measured based on a known signal. For example (e.g., in LTE), the WTRU or UE may use a cell-specific reference symbol (CRS) for such measurement and / or, for cells that can transmit a positioning reference signal (PRS), the WTRU or UE may use its PRS, for example. To perform positioning, the WTRU or UE may receive supporting information or assistance data, such as information associated with the cell and / or signal to be measured. For OTDOA, the assistance data may include PRS relation parameters.In an exemplary embodiment, support for OTDOA by a WTRU or UE may be optional, and the use of CRS or PRS for a given cell may be implemented and / or determined by the implementation of the WTRU or UE.

[0087] In one exemplary embodiment, a positioning reference signal (PRS) may be transmitted by an eNB such that the eNB can recognize or know the transmission parameters for a cell under its control. For a given cell, the PRS may be defined to be provided in or included in N PRS consecutive downlink subframes for each positioning instance (e.g., a PRS positioning occasion), for example, the first subframe of the N PRS downlink subframes may satisfy or be able to achieve

[0088]

Number

[0089] According to one exemplary embodiment, N PRS can be 1, 2, 4, and / or 6 subframes, and the parameters T PRS and Δ PRSThese can be the PRS period and the PRS offset, respectively. In addition, the PRS period can be 160, 320, 640, and / or 1280 subframes, and the PRS offset can be a value between 0 and the PRS period minus 1, or a value one less than the PRS period. The PRS BW (bandwidth) can be narrowband or wideband so that the PRS BW occupies a partial BW of the cell (e.g., a portion of the complete or overall BW) and / or the complete BW of the cell. The BW value can include, for example, 6, 15, 25, 50, 75, and / or 100 resource blocks (RBs). In one embodiment, if the PRS can occupy a partial BW, the RBs may be at the center of the bandwidth or at any other preferred location within the bandwidth. Parameters that can be used for PRS for a cell, can be provided for PRS for a cell, can be defined for PRS for a cell, and / or can be used to define PRS for a cell (e.g., PRS information and / or prs-info) are the number of DL subframes (e.g., N PRS ), T PRS and Δ PRS It may include one or more of the following: a PRS configuration index (e.g., 0 to 4095) which can be used (e.g., in a table or other suitable structure) to obtain (e.g., PRS period and offset), PRS BW, PRS muting information which can define when a PRS opportunity may be muted (e.g., not sent) in a cell, and similar.

[0090] According to one embodiment, PRS positioning opportunities may be muted periodically within a cell. The PRS muting configuration may be defined by a periodic PRS muting sequence which may have periods of 2, 4, 8, and / or 16 positioning opportunities in an embodiment. PRS muting information is provided using a p-bit field for period p, where each bit corresponds to a PRS positioning opportunity in each muting sequence and / or can indicate whether that opportunity is muted. If PRS positioning opportunities may be muted within a cell, the PRS may have N of a particular opportunity within that cell. PRS individual subframes (for example, N PRS It cannot be transmitted in any of the subframes.

[0091] In addition, PRS meeting information may be signaled to the WTRU or UE in positioning support data (for example, PRS muting information may be included in the positioning support data and signaled together with that data). The first bit of the PRS muting sequence corresponds to the first PRS positioning opportunity that may begin after the start of a zero system frame number (SFN) (e.g., SFN=0), where the SFN may be the SFN of the OTDOA reference cell of the WTRU or UE.

[0092] Figure 8 shows one embodiment as an example of an architecture that may be used for positioning. According to one embodiment, the architecture shown in Figure 8 can be used in an LTE communication system such as the communication system 100 shown in Figures 1A and 1C-1E, and can perform positioning for the LTE communication system. As shown in Figure 8, positioning of a UE or WTRU, or positioning by a UE or WTRU, may be controlled by an Enhanced Serving Mobile Location Center (E-SMLC). In one example embodiment, communication between the WTRU and the E-SMLC may be point-to-point and / or transparent to the eNB. The WTRU or UE can communicate with the E-SMLC using a protocol such as the LTE Positioning Protocol (LPP) on a control plane or data plane as shown in Figure 8. Such communication (e.g., between the WTRU or UE and the E-SMLC) may be encapsulated in signaling or data between the eNB and the WTRU or UE, or between a Secure User Plane Location (SUPL) Location Platform (SLP) and the WTRU or UE. According to one embodiment as an example, the eNB cannot verify what it believes to be in the LPP message. Communication between the E-SMLC and the WTRU may pass through a Mobility Management Entity (MME) or SLP, which may direct communication to and / or from the appropriate WTRU, and may or may not verify the content of the communication, and may or may not modify the content of the communication and / or transport. Communication may be possible or mapped via the SLP and / or via a SUPL bearer if the WTU or UE may be a SUPL-enabled terminal (SET).

[0093] In addition, information that may pass through or be exchanged between the WTRU or UE and the E-SMLC may include one or more of the following: the WTRU or UE's ability to support OTDOA positioning; commands from the E-SMLC to perform OTDOA measurements; OTDOA positioning support data from the E-SMLC to the WTRU or UE, such as which cells are the reference and / or additional or adjacent cells for OTDOA; and measurement reports from the WTRU or UE to the E-SMLC. The support data or other exchanged information may include information such as cell ID and / or carrier frequency, and / or PRS information for the reference cell and / or additional or adjacent cells. Since PRS transmission may be the role of the eNB, the E-SMLC may obtain at least some of the PRS information from one or more eNBs, in which case communication between the E-SMLC and the eNB may be via an LPPa interface or protocol.

[0094] According to one exemplary embodiment, a communication system may be provided with and / or used one or more transmission modes for transmitting and / or receiving information, data, and / or signals. Table 3 shows exemplary embodiments of transmission modes for a communication system (e.g., LTE and / or LTE-Advanced systems) that may be used to supply the information and / or signals disclosed herein. The transmission modes provided in Table 3 (except for TM-7, 8, and 9 in one embodiment) may use CRS for both demodulation and measurement. In addition, for TM-7 and 8 shown in Table 3, DM-RS may be used for demodulation and CRS for measurement. According to one embodiment, for TM-9 shown in Table 3, DM-RS and CSR-RS may be used for demodulation and measurement, respectively.

[0095] [Table 2]

[0096] According to one embodiment as an example, channel state information (CSI) feedback can be provided and used. For example, multiple (e.g., two) types of reporting channels can be used, such as PUCCH and / or PUSCH. The PUCCH reporting channel can provide CSI feedback while tolerating limited feedback overhead. The PUSCH reporting channel can tolerate a large amount of feedback overhead, although it is less reliable. The PUCCH reporting channel can be used for periodic CSI feedback for coarse link adaptation, and / or PUSCH reporting can be triggered aperiodically for finer link adaptation.

[0097] [Table 3]

[0098] Downlink control channels can also be implemented and / or used. A downlink control channel can occupy the first 1 to 3 OFDM symbols within each subframe, depending on the overhead of the control channel. This dynamic resource allocation to handle the overhead of the downlink control channel enables efficient use of downlink resources, which can result in improved system throughput. Various types of downlink control channels, such as PCFICH (Physical Control Format Indicator Channel), PHICH (Physical Hybrid ARQ Indicator Channel), and / or PDCCH (Physical Downlink Control Channel), can be transmitted within the downlink control channel region within each subframe. A downlink control channel resource unit can be defined as four consecutive REs in the frequency domain, referred to as a REG (Resource Element Group), as shown in Figures 9 and 10. Figure 9 shows an exemplary REG definition within the downlink control channel region with a 2Tx CRS. Figure 10 shows an exemplary REG definition within the downlink control channel region with a 4Tx CRS. As illustrated, if CRS can be located within the same OFDM symbol, REG can be defined by four consecutive REs without CSR.

[0099] In another embodiment, a Physical Control Format Indicator Channel (PCFICH) may be provided and / or used as described herein. For example, the PCFICH may be transmitted in the 0th OFDM symbol within each subframe and / or may indicate the number of OFDM symbols used for the downlink control channel in that subframe. Dynamic resource allocation of the downlink control channel at the subframe level may be made possible by using the PCFICH. A WTRU or UE may detect a CFI (Control Format Indicator) from the PCFICH, and the downlink control channel region may be defined in the subframe according to the CFI value. Table 5 shows the CFI codewords that may be detected from the PCFICH, and Table 6 shows the details of the resource allocation of the downlink control channel according to the CFI value, subframe type, and system bandwidth. In some embodiments, the PCFICH may be skipped if the subframe is defined as a non-PDSCH supportable subframe such that the WTRU or UE is not attempting to detect the PCFICH in the subframe.

[0100]

Table 4

[0101]

Table 5

[0102] In one embodiment, four REGs are used for PCFICH transmission in the 0th OFDM symbol within a subframe, and / or the REGs may be uniformly distributed across the system bandwidth to utilize frequency diversity gain. The starting point of PCFICH transmission may vary according to the physical cell ID (PCI) as shown in FIG. 11. The frequency shift of the PCFICH associated with the cell ID can achieve the diversity order 4 from the distributed allocation while avoiding PCFICH collisions between multiple adjacent cells, thereby realizing the PCFICH detection performance. In a WTRU or UE receiver, the procedure (e.g., the first procedure) for detecting the downlink control channel may be the step of decoding the PCFICH to calculate the number of OFDM symbols within a subframe. If the downlink control resource can be defined by the PCFICH, as a result of a PCFICH detection error, a downlink grant, an uplink grant, and / or the loss of PHICH reception may occur.

[0103] A physical hybrid ARQ indicator channel (PHICH) may be provided and / or used as described herein. In one embodiment, by using the PHICH, an ACK or NACK can be transmitted in response to the PUSCH transmitted in an uplink subframe. The PHICH may be transmitted in a distributed manner across the system bandwidth and OFDM symbols within the downlink control channel. The number of OFDM symbols is defined as the duration of the PHICH and may be configurable via upper layer signaling. The position of the PHICH resource may vary according to the duration of the PHICH.

[0104] FIG. 12 shows an exemplary resource allocation of the PCFICH and PHICH (e.g., allocation of PCFICH and PHICH REGs by PCI). As shown in FIG. 12, a plurality of PHICH groups are defined within a cell, the PHICH group can include a plurality of PHICHs together with orthogonal sequences, and the PHICH for a WTRU or UE is the lowest PRB index

[0105]

number

[0106] and DM-RS circulating shift (n DMRS It can be dynamically defined along with resource information in uplink permissions such as ). Two index pairs (PHICH group index)

[0107]

number

[0108] PHICH sequence index

[0109]

number

[0110] ) can indicate a PHICH resource for a specific WTRU or UE. PHICH index vs

[0111]

number

[0112] In this context, each index is:

[0113]

number

[0114]

number

[0115] It can be defined as, however,

[0116]

Number

[0117] means the number of PHICH groups available in the system,

[0118]

Number

[0119] can be defined as, provided that N g is 2-bit information transmitted by PBCH (Physical Broadcast Channel), and this information may be such that N g ∈ {1 / 6, 1 / 2, 1, 2}.

[0120] In addition, orthogonal sequences according to the spreading factor may also be provided and / or used, for example, as shown in Table 7.

[0121]

Table 6

[0122] The Physical Downlink Control Channel (PDCCH) may be provided and / or used as described herein. For example, the PDCCH may be defined with one or a plurality of consecutive CCE resource blocks where one CCE (Control Channel Element) can contain 9 REGs. The number of available CCEs (N CCE ) may be defined as N CCE = [N REG / 9], provided that N REGThis can be the number of REGs not assigned to PCFICH or PHICH. Table 8-1 shows exemplary available PDCCH formats with definitions of several consecutive CCEs that may be provided, used, and / or supported. As shown in Table 8-1, four PDCCH formats are supported, and / or the number of CCEs in each PDCCH format may differ. The number of CCEs in a PDCCH format may be referred to as the aggregation level.

[0123] [Table 7]

[0124] In one embodiment, the WTRU or UE can monitor PDCCH candidates and / or blind decode them a given number of times (e.g., as shown in Table 8-2). The set of PDCCH candidates that can be monitored by the WTRU or UE can be defined as the search space.

[0125] [Table 8]

[0126] Aggregation levels {1, 2, 4, 8} are supported within WTRU or UE-specific search spaces, and aggregation levels {4, 8} may be supported within a common search space. Search space at aggregation level L ∈ {1, 2, 4, 8}

[0127]

number

[0128] This can be defined as a set of PDCCH candidates. For each serving cell in which a PDCCH may be monitored, the search space

[0129]

number

[0130] The CCE corresponding to candidate m of the PDCCH is,

[0131]

number

[0132] Given by, however Y k m' is defined as described herein and can be i=0, ..., L-1. For the common search space, m'=m. In addition, for the search space specific to a WTRU or UE, and for a serving cell that a PDCCH may monitor, if the monitored WTRU or UE may consist of carrier indicator fields, then m'=m+M (L) ·n C1 And, however, n C1 m' can be a carrier indicator field value. Otherwise, if the monitored WTRU or UE cannot be composed of a carrier indicator field, then m'=m, where m=0, ...,M (L) -1, M (L) Y can be considered the number of PDCCH candidates to be monitored within the given search space. For the common search space, Y k This can be set to 0 for two aggregation levels, L=4 and L=8. WTRU or UE specific search space at aggregation level L.

[0133]

number

[0134] Regarding the variable Y, k is Y k =( A·Y k-1 ) is often defined modulo D, however Y -1 =n RNTI ≠0, A=39827, D=65537, and

[0135]

number

[0136] n s This can be the slot number within the wireless frame.

[0137] As described herein, a PDCCH can be enhanced by transmitting the PDCCH in the PDCCH domain with a WTRU or UE-specific reference signal so that beamforming gain, frequency domain ICIC, and / or PDCCH capacitance improvement gain are achieved and / or improved (e.g., an ePDCCH can be realized). Figure 13 shows an exemplary ePDCCH multiplexing (FDM multiplexing) with a PDSCH.

[0138] In one embodiment, as an example, PUCCH may be allocated with respect to PDCCH. For example, the physical resources used for PUCCH are provided by the upper layer.

[0139]

number

[0140] and / or

[0141]

number

[0142] It may depend on one or more parameters such as variables.

[0143]

number

[0144] This variable may represent the bandwidth of resource blocks that may be available for use by PUCCH format 2 / 2a / 2b transmission within each slot.

[0145]

number

[0146] This can represent the number of cyclic shifts used for PUCCH format 1 / 1a / 1b in resource blocks used for mixing formats 1 / 1a / 1b and 2 / 2a / 2b.

[0147]

number

[0148] is within the range {0, 1, ..., 7}

[0149]

number

[0150] It is an integer multiple of,

[0151]

number

[0152] This may be provided by a higher layer. In one embodiment, the mixed resource blocks are

[0153]

number

[0154] If that is the case, it cannot exist. In addition, there may be (e.g., at most) one resource block in each slot that supports a mixture of formats 1 / 1a / 1b and 2 / 2a / 2b. Resources that can be used to send PUCCH formats 1 / 1a / 1b, 2 / 2a / 2b, and 3 are non-negative index

[0155]

number

[0156] and

[0157]

number

[0158] They can be represented by each of the following:

[0159] Mapping to physical resources may be provided and / or used, for example, as described herein. In such embodiments, a block of complex numerical symbols

[0160]

number

[0161] is the transmission power P PUCCH To confirm the amplitude magnification β PUCCH Multiplied by, and / or

[0162]

number

[0163] The sequence starting from can be mapped to resource elements. PUCCH can use one resource block in each of the two slots within a subframe. Within the physical resource block used for transmission, the resource element (k,l) of antenna port p, which is not used for transmitting the reference signal, can be mapped to resource elements.

[0164]

number

[0165] The mapping can be in ascending order of k first, then l, and then slot number, starting from the first slot in the subframe. Index

[0166]

number

[0167] A relationship can be defined between the antenna port number p.

[0168] slot n S The physical resource blocks that can be used to send PUCCH are:

[0169]

number

[0170] Given, However, the variable m may be assumed to depend on the PUCCH format. For formats 1, 1a, and 1b:

[0171]

number

[0172] For formats 2, 2a, and 2b

[0173]

number

[0174] And for Format 3

[0175]

number

[0176] That is the case.

[0177] The mapping of modulation symbols to the physical uplink control channel may be as illustrated in Figure 14. In embodiments of simultaneous transmission of a sounding reference signal and PUCCH formats 1, 1a, 1b, or 3, a shortened PUCCH format may be used in which the last SC-FDMA symbol in the second slot of the subframe may be left empty, if one serving cell can be configured.

[0178] FDD HARQ-ACK procedures and / or methods may be provided for configured serving cells. For example, for PUCCH format 1a / 1b, HARQ-ACK transmission of two antenna ports (p∈[p0, p1]) may be supported. For the FDD and one configured serving cell, the WTRU or UE will provide PUCCH resources

[0179]

number

[0180] This is used to map antenna port p to PUCCH format 1a / 1b as described below.

[0181]

number

[0182] A HARQ-ACK can be sent in subframe n (for example, if one or more of the following apply):

[0183] For PDSCH transmissions indicated by the detection of the corresponding PDCCH in subframe n-4, or for PDCCHs indicating a downlink SPS release in subframe n-4, the WTRU or UE shall, in subframe n, for antenna p0

[0184]

number

[0185] You can use n CCE is the number of the first CCE used to send the corresponding DCI assignment (e.g., the lowest CCE index used to construct the PDCCH), and / or

[0186]

number

[0187] It can be composed of higher layers. In 2-antenna port transmission, the PUCCH resource for antenna port p1 is,

[0188]

number

[0189] It can be given by.

[0190] For primary cell PDSCH transmissions where the corresponding PDCCH cannot be detected in subframe n-4, the value

[0191]

number

[0192] This can be determined according to the configuration of the upper layer. For a WTRU or UE configured for 2 antenna port transmission, the PUCCH resource value will be two PUCCH resources, with the first PUCCH resource for antenna port p0.

[0193]

number

[0194] , a second PUCCH resource for antenna port p1

[0195]

number

[0196] It can be mapped in this way. Otherwise, the PUCCH resource value will be a single PUCCH resource for antenna port p0.

[0197]

number

[0198] It can be mapped to.

[0199] The FDD HARQ-ACK feedback procedure for multiple configured serving cells may be based on PUCCH format 1b, for example, using the channel selection HARQ-ACK procedure or the PUCCH format 3 HARQ-ACK procedure. For PUCCH format 3, HARQ-ACK transmission from two antenna ports (p∈[p0, p1]) may be supported.

[0200] For PUCCH format 1b with FDD and channel selection with two configured serving cells, the WTRU or UE is PUCCH resource

[0201]

number

[0202] Selected from A PUCCH Resources

[0203]

number

[0204] Above, b(0)b(1) can be sent, where 0≦j≦A-1 and A∈{2, 3, 4}. HARQ-ACK(j) can represent an ACK / NACK / DTX response to a transport block or SPS release PDCCH associated with serving cell c, and HARQ-ACK(j) and A Transport blocks and / or serving cells for PUCCH resources may be provided by a table.

[0205] A WTRU or UE configured in transmit mode that can support up to two transport blocks on serving cell c may use the same HARQ-ACK response in the transport block as a response to a PDSCH transmit by a single transport block or PDCCH that directs a downlink SPS release associated with serving cell c.

[0206] In addition, WTRU or UE is associated with HARQ-ACK(j)(0≦j≦A-1) according to one or more embodiments described herein (for example, one or more of the embodiments below as examples). A PUCCH Resources

[0207]

number

[0208] It is possible to make a decision.

[0209] For PDSCH transmissions indicated by the detection of the corresponding PDCCH in subframe n-4 of the primary cell, or for PDCCHs indicating a downlink SPS release in subframe n-4 of the primary cell, the PUCCH resource will:

[0210]

number

[0211] For transmit modes that support up to two transport blocks, the PUCCH resource may be used.

[0212]

number

[0213] teeth,

[0214]

number

[0215] It is fine to assume that it is given by, however n CCE This is the number of the first CCE used for transmitting the corresponding PDCCH, and also

[0216]

number

[0217] It can be composed of upper layers.

[0218] For primary cell PDSCH transmissions where the corresponding PDCCH cannot be detected in subframe n-4, the value

[0219]

number

[0220] This can be determined according to the configuration of the upper layer. For transmit modes that support up to two transport blocks, see the PUCCH resource.

[0221]

number

[0222] teeth,

[0223]

number

[0224] It can be given by.

[0225] For PDSCH transmissions indicated by the detection of the corresponding PDCCH in subframe n-4 of the secondary cell, the value for the transmit mode supports up to two transport blocks.

[0226]

number

[0227] and value

[0228]

number

[0229] This can be determined according to the configuration of the upper layer. The TPC field in the DCI format of the corresponding PDCCH can be used to determine the PUCCH resource value from one of the resource values ​​(e.g., four resource values) configured by the upper layer. For a WTRU or UE configured for a transmit mode that supports up to two transport blocks, the PUCCH resource value can be multiple (e.g., two) PUCCH resources.

[0230]

number

[0231] It can be mapped to a single PUCCH resource. Otherwise, the PUCCH resource value is mapped to a single PUCCH resource.

[0232]

number

[0233] It can be mapped to.

[0234] Resource allocation can be performed in carrier aggregation situations. In ePDCCH transmission, centralized and distributed resource allocation can be implemented to better support UEs with different channel states in a cell. In centralized resource allocation, frequency selectivity gain can be allowed so that the eNB scheduler can improve spectral efficiency by utilizing channel state information of WTRUs or UEs where low Doppler frequencies are occurring. In distributed resource allocation, frequency diversity gain can be defined so that reliable PDCCH transmission performance is achieved without channel state information, which may be appropriate for WTRUs or UEs that are adversely affected by high Doppler frequencies. Currently, ePDCCH is designed based on a single-component carrier, and therefore, performance may be limited when such a design is used in a multi-carrier network.

[0235] In systems with multiple component carriers, centralized and distributed resource allocation can be optimized to match frequency-selective scheduling gains and / or frequency diversity gains. Such ePDCCH designs can be single-component carrier-focused, to the extent that their performance is limited in multi-carrier systems.

[0236] In addition, a WTRU or UE can provide a HARQ-ACK response in subframe n+4 when the WTRU or UE receives a PDSCH in subframe n. Since blind detection of a PDCCH may require or desire a portion of the time before starting to decode the PDSCH, the PDSCH processing time can be reduced to less than 4ms. Time advances can further reduce the PDSCH processing time, assuming, for example, the largest transport block size, highest rank, and / or longest time advance is considered, so that the WTRU or UE completes its decoding process before n+4. Thus, the PDSCH processing time can be further reduced. Since ePDCCHs can be transmitted in the PDSCH region, this can reduce the PDSCH processing time, for example, doubling the maximum transport block size in a multi-carrier system. Similar processing time reductions may be observed for aperiodic CSI reports. Aperiodic CSI reporting is triggered by the downlink control channel, and CSI feedback processing time is reduced by ePDCCH reception, which can become even more critical as the number of component carriers increases simultaneously for CSI reporting. Unfortunately, as described, PDSCH processing time and aperiodic CSI reporting processing time in WTRU or UE receivers can now be more stringent because ePDCCH is used instead of legacy PDCCH. These issues could become even more severe if carrier aggregation is now used.

[0237] In addition, uplink control channel assignment can also be performed. For example, the FDD HARQ-ACK feedback procedure can be based on PUCCH format 1a / 1b (e.g., dynamically assigned PUCCH format 1a / 1b) for one configured serving cell (e.g., in single-cell operations such as Rel-8 or R8). For two or more DL serving cells to an FDD, the PUCCH feedback can use PUCCH format 1b with channel selection (e.g., dynamically assigned PUCCH format 1b) (e.g., if two DL serving cells are used) or PUCCH format 3 in combination with ARI (e.g., semi-statically configured PUCCH format 3) (e.g., if three or more configured serving cells are used). In TDDs (e.g., Rel-10 TDDs), single-cell operations may be based on PUCCH format 1 with channel selection (e.g., dynamically assigned PUCCH format 1). PUCCH format 1 with channel selection (for example, when two or more DL serving cells may be used) and / or PUCCH format 3 or PUCCH F3 may be used as functions of the RRC configuration.

[0238] In one embodiment, for a dynamically derived PUCCH resource, for example, in the case of a DL allocation received on the primary serving cell by a single carrier operation or DL ​​carrier aggregation, and for a PDSCH transmission indicated by the detection of the corresponding PDCCH in subframe n-4 of the primary cell, and / or for a PDCCH indicating a downlink SPS release in subframe n-4 of the primary cell, the PUCCH resource is:

[0239]

number

[0240] For transmit modes that may be and / or support up to two transport blocks, the PUCCH resource is:

[0241]

number

[0242] teeth,

[0243]

number

[0244] It may also be by, however, n CCE This is the number of the first CCE used for transmitting the corresponding PDCCH, and also

[0245]

number

[0246] This can be composed of higher layers. In one embodiment using PUCCH format 3, the PUCCH index is pre-configured through RRC and / or for a given DL subframe n-4, and the corresponding PUCCH index in UL subframe n can be derived from the ARI transmitted in the TPC field of the DL assignment message of SCell.

[0247] In single-carrier operation mode, the structure and / or resource area of ​​the ePDCCH may differ from that of a legacy PDCCH; therefore, the PUCCH resource allocation mechanism may be specified to allow the allocation of PUCCH resources to users or UEs (or WTRUs) that decode DCI using the ePDCCH, which may be difficult in multi-carrier configurations. In addition, for DL ​​carrier aggregation, the PUCCH resource allocation mechanism may be used to allow users (or WTRUs) decoding the ePDCCH on at least one of the DL serving cells to send ACK / NACK information corresponding to scheduled DL data transmissions on the primary and one or more secondary serving cells.

[0248] Frame structure 2TDD support can also be provided. In a TDD system, PDSCHs can be transmitted in PDSCH regions within downlink subframes and / or PDSCH regions within subframes (e.g., DwPTS). In DwPTS (e.g., downlink pilot time slots where a large number of OFDM symbols are reserved for downlink transmissions within a special subframe), the number of OFDM symbols available for PDSCH transmissions may be limited and / or vary depending on the configuration. Since legacy PDCCHs can be transmitted together in the same subframe, embodiments of ePDCCH transmission may be provided separately.

[0249] If multiple component carriers can be configured with different DL-UL subframe configurations within a TDD system, the downlink control channel may not support certain downlink subframes in secondary cells, for example, when cross-carrier scheduling may be used. As a result, downlink subframes may be wasted in secondary cells. Because the number of OFDM symbols in DwPTS may be insufficient and / or the number of OFDM symbols for PDSCH transmissions may change, ePDCCH transmissions by subframes may now be required (e.g., as described below), or detailed WTRU or UE behavior may be defined to help avoid errors (e.g., as described below).

[0250] PDCCH fallbacks may be provided. For example, when ePDCCH is supported by legacy PDCCH in the network, a WTRU or UE may be configured to a specific PDCCH type via upper-layer signaling. In one such embodiment, there may be a period of ambiguity during which the eNB scheduler does not know whether the WTRU or UE can monitor the RRC-signaled PDCCH type. PDCCH fallback transmissions, which may be received by the WTRU or UE regardless of the configured PDCCH type, may be defined to avoid wasting resources and / or unexpected WTRU or UE behavior. In one such embodiment, the WTRU or UE may be configurable semi-statically between legacy PDCCH and ePDCCH via upper-layer signaling, and the WTRU or UE may need to be able to receive PDCCHs sequentially or continuously during the configuration process.

[0251] Resource collisions can further occur between PRS and ePDCCH. For example, when ePDCCH is used in a cell, the PRS transmitted by the cell may overlap with or collide with some REs of the ePDCCH transmission. If the PRS BW overlaps with the ePDCCH transmission BW, the PRS transmission may collide with the DM-RS of the ePDCCH transmission. An example of this collision is shown in Figure 15. As shown in Figure 15, Vshift may be 0. Such overlaps can result in performance degradation, which currently places too much burden on the WTRU or UE to properly decode the ePDCCH. The eNB cannot know which WTRU or UE is aware of the PRS transmission, because the WTRU or UE's support for OTDOA, the performance of relevant measurements, and / or knowledge of the PRS information may be based, for example, on transparent communication between the WTRU or UE and the E-SMLC. In addition, systems and / or methods for handling and / or avoiding such collisions may be provided herein.

[0252] As described herein, systems and / or methods may be provided for providing ePDCCHs that can be used by multiple carriers. For example, definitions or descriptions of resources such as ePDCCH resource configurations may be provided. In an ePDCCH resource configuration, resource elements (REs) in a subframe may be used for ePDCCHs that satisfy one or more of the following: not colliding with downlink antenna ports 0 to 22 (e.g., reference signals) excluding antenna ports {4, 5}; not being occupied by PCFICH, PHICH, and / or PDCCH; not being used for PSS / SSS and / or PBCH; not being configured as muted REs (e.g., zero-power CSI-RS, ABS, null REs); not being used for PDSCHs; not being used for PMCHs for configured MBFSN subframes; and / or being used for the above purposes but being differential by applying mutually orthogonal patterns to both ePDCCHs and non-ePDCCHs (e.g., as described herein).

[0253] Resources configured for FDD and TDD (e.g., in a single DL carrier) may also be provided. For example, a subset of physical resource blocks (PRBs), which may be called PRB pairs or RBs within a subframe, may be configured for ePDCCH transmission, and the ePDCCH resources may be supplied to the WTRU or UE by using broadcast channels (e.g., MIB, SIB-x) and / or higher-layer signaling (e.g., PRC, MAC, and similar). The subset of PRBs may be consecutive PRBs or distributed PRBs. If the system bandwidth can be 5 MHz (e.g., if 25 PRBs are available,

[0254]

number

[0255] ), a subset of PRB for ePDCCH

[0256]

number

[0257] It may be considered to be composed of, however,

[0258]

number

[0259] Figure 16 shows an example of an ePDCCH multiplexed with a PDSCH, in which case the ePDCCH resources can be allocated within a subframe. A PRB-level ePDCCH multiplexed with a PDSCH can be used (for example, as shown in the figure).

[0260] In one embodiment, the ePDCCH PRB may be reserved, for example, to enable a reduction in the complexity of simpler ePDCCH reception and / or blind decoding. In addition, the ePDCCH PRB may be configured at the PRB pair level and may include one or more of the following: For example, the resource allocation type used for PDSCH transmission may include source allocation type 0, which may be a bitmap-based instruction by resource block groups (RBGs) that can be defined according to the system bandwidth; resource allocation type 1, which may be a bitmap-based instruction by a subset of RBGs; and resource allocation type 2, which may be a sequential resource allocation (e.g., a starting RB number and / or length may be specified), and the resource allocation type for ePDCCH resources may differ depending on the ePDCCH mode (e.g., distributed and centralized transmission), for example, resource allocation type 0 may be used for centralized transmission and source allocation type 1 may be used for distributed allocation, and / or RBs for centralized and distributed transmission may overlap, i.e., PRB pairs are used for centralized and distributed transmission. In addition, bitmap instruction may be used per PRB pair level, NDL,PRB A bitmap is provided for each PRB level to indicate which ePDCCH resources can use bits, N DL,PRB This can indicate the number of PRB pairs in the downlink system. In some embodiments, predefined PRBs may also be used. For example, multiple PRB pair subsets may be defined for the ePDCCH, and / or the number of subsets may be notified to the WTRU or UE. Each PRB pair subset may contain one or more PRB pairs, and the PRB pairs included in a PRB pair subset may be mutually orthogonal to another PRB pair subset. At least one of the PRB pair subsets may be used without configuration. A PRB pair subset may be used for a common search space or for a first PRB pair subset for a WTRU or UE-specific search space. The number of subsets may be notified to the WTRU or UE dynamically. For example, the number of subsets may be indicated within each subframe that the WTRU or UE can monitor or receive from the ePDCCH. Predefined PRBs may be used for a common search space. Configuration-based PRBs may be used for a WTRU or UE-specific search space. The embodiments of the ePDCCH PRB described herein can be used for each ePDCCH resource set when multiple ePDCCH resource sets may be configured for a WTRU or UE. The ePDCCH resource sets and ePDCCH regions can be used interchangeably.

[0261] According to one embodiment as an example, a WTRU or UE may have specific operations to monitor an ePDCCH based on a given ePDCCH instruction. For example, an ePDCCH resource may be notified to the WTRU or UE via a broadcast channel and / or RRC signaling. The WTRU or UE may monitor an ePDCCH in its search space which may be within a subset of PRBs configured for the ePDCCH. A subset of PRBs may be notified to the WTRU or UE implicitly or explicitly by dynamic instruction. For example, instruction bits may be transmitted in a subframe, and / or a DM-RS scramble sequence may indicate which subset of PRBs configured for the ePDCCH may be used. ePDCCH resources are communicated to the WTRU or UE by an ePDCCH resource index (ERI) from a set of ePDCCH configurations, and / or the ERI may be communicated via upper-layer signaling or implicitly derived from a subframe index and / or SFN, Cell-ID, and / or RNTI (e.g., C-RNTI, P-RNTI, S1-RNTI). The WTRU or UE may be communicated regarding types of ePDCCH resources, such as "system ePDCCH resources" and / or "WTRU or UE-specific ePDCCH resources". The behavior of the WTRU or UE associated with these ePDCCH resource types may include one or more of the following: The WTRU or UE may receive system ePDCCH resource information via a broadcast channel or upper-layer signaling. The WTRU or UE may receive WTRU or UE-specific ePDCCH resource information from upper-layer signaling. WTRU or UE-specific ePDCCH resources may be the same as system ePDCCH resources. WTRU or UE-specific ePDCCH resources may be a subset of system ePDCCH resources in the time and / or frequency domain. For example, a subset of PRBs within a subframe and / or a subset of time subframes / frames may be WTRU or UE-specific ePDCCH resources.In some embodiments, a WTRU or UE cannot receive a PDSCH in a system ePDCCH resource that cannot be in a WTRU or UE-specific ePDCCH resource (e.g., it is not expected to receive one). A WTRU or UE can receive a PDSCH in a system ePDCCH resource that cannot be in a WTRU or UE-specific ePDCCH resource (e.g., it is expected to receive one). A WTRU or UE can receive a PDSCH in a WTRU or UE-specific ePDCCH resource when the ePDCCH cannot be transmitted in an ePDCCH PRB pair (e.g., it is expected to receive one).

[0262] According to one embodiment as an example, the ePDCCH PRB may consist of multiple steps, such as long-term and short-term ePDCCH resources. For example, long-term ePDCCH resources may be defined semi-statically, and / or short-term ePDCCH resources may be defined dynamically within the long-term ePDCCH resources. Furthermore, long-term ePDCCH resources, cell-specific ePDCCH resources, semi-static ePDCCH resources, temporal ePDCCH resources, and / or ePDCCH resources configured in higher layers may be used interchangeably.

[0263] In one embodiment, a long-term ePDCCH resource may be a set of PRB pairs within the system bandwidth. Resource allocation types 0, 1, or 2 may be used to designate a set of PRB pairs as a long-term ePDCCH resource. A large number of bits (e.g.,

[0264]

number

[0265] ) may be used for bitmap-based allocation to support flexibility (e.g., full flexibility). Resource directives for long-term ePDCCH resources may be communicated to the WTRU or UE via broadcast or higher-layer signaling. The WTRU or UE may know, or assume, that a portion of the long-term ePDCCH resources (e.g., PRB pairs) may be used for PDSCH transmissions. If a PDSCH resource allocation may conflict with long-term ePDCCH resources but not with short-term ePDCCH resources, the WTRU or UE may know, or assume, that PDSCH may be transmitted on those resources. If a PDSCH resource allocation conflicts with both long-term and short-term ePDCCH resources, the WTRU or UE may assume that PDSCH cannot be transmitted on those resources and / or perform rate matching around those resources.

[0266] Short-term ePDCCH resources may be referred to as WTRU or UE-specific ePDCCH resources, dynamic ePDCCH resources, per-subframe ePDCCH resources, and / or L1 signaling-based ePDCCH resources. Short-term ePDCCH resources may also be subsets of long-term ePDCCH resources. A subset of ePDCCH resources may be directed within each subframe so that the eNB can move the subset of ePDCCH resources from one subframe to another.

[0267] Instructions for short-term ePDCCH resources may be based on explicit signaling. Explicit signaling may include one or more instruction bits transmitted in the same subframe, and / or the location of the instruction bits may be fixed. According to one embodiment of the example, the fixed location may be the lowest index of the PRB pair configured for the long-term ePDCCH resource. The fixed location may be predefined regardless of whether the ePDCCH resource is long-term or short-term. For example, it may be the lowest index of the PRB pair within the system bandwidth. The fixed location may be based on distributed transmission.

[0268] Instructions for short-term ePDCCH resources can be based on implicit signaling. This implicit signaling may be a DM-RS in a PRB pair configured as a short-term ePDCCH resource that can be scrambled, and a specific scramble code known to the eNB and / or WTRU or UE. Thus, the WTRU or UE can check a long-term ePDCCH resource with a specific scramble code and calculate the short-term ePDCCH resource. After the WTRU or UE has completed the calculation (e.g., determination) of the short-term ePDCCH resource, a WTRU or UE-specific search space may be defined by the short-term ePDCCH resource. Therefore, the WTRU or UE can monitor ePDCCH within a WTRU or UE-specific search space. Short-term resources can be configured in a WTRU or UE-specific manner. The WTRU or UE may assume, for example, that a PDSCH cannot be transmitted in a PRB pair configured for a long-term ePDCCH resource, even if the PRB pair might not be in the short-term ePDCCH resource. Short-term resources may be configured in a cell-specific manner. A WTRU or UE may receive a PDSCH in a PRB pair configured for a long-term ePDCCH resource, for example, if the PRB pair may not be within a short-term ePDCCH resource.

[0269] Multiple ePDCCH resource sets are presented or described herein, and / or subsets of ePDCCH resource sets may be used within a subframe. The number of ePDCCH resource sets may be configurable by the eNB. The number of ePDCCH resource sets may be fixed regardless of the system configuration. A subset of ePDCCH resource sets may be configured for a particular WTRU or UE as a WTRU or UE-specific search space. A subset of ePDCCH resource sets for a particular WTRU or UE may be predefined as a function of C-RNTI and / or the number of subframes. For example, N of ePDCCH resource sets ePDCCH If n subsets are defined and one of the subsets of the ePDCCH resource set can constitute a particular WTRU or UE, the following expression can be used to select which ePDCCH resource set can be used for the WTRU or UE: The subset of the ePDCCH resource set for a particular WTRU or UE is k=n RNTI mod N ePDCCH It can be defined as follows. Table 8-3 shows an example of a subset configuration when four ePDCCH resource sets can be defined. In the table, "v" may be considered to represent a set that can be included in a subset. In addition, k=n RNTI Mod 3 can be used in Table 8-3.

[0270] [Table 9]

[0271] An ePDCCH resource set can have one or more PRB pairs, and / or the number of PRB pairs per ePDCCH resource set can be fixed. For example, N set Each PRB pair is grouped as an ePDCCH resource set, N set Each PRB pair can be continuous or distributed across the system bandwidth.

[0272] In addition, an ePDCCH resource set can be configured as a centralized ePDCCH resource or a distributed ePDCCH resource. If an ePDCCH resource set can be defined as a centralized ePDCCH resource, then the eCCEs within the ePDCCH resource set can be defined as centralized ePDCCH transmits (LeCCEs). Multiple LeCCEs can be defined in a single ePDCCH resource set. REs for LeCCEs can be placed within a PRB pair. If an ePDCCH resource set can be defined as a distributed ePDCCH resource, then the eCCEs within the ePDCCH resource set can be defined as distributed ePDCCH transmits (DeCCEs). Multiple DeCCEs can be defined in an ePDCCH resource set. REs for DeCCEs can be placed across two or more PRB pairs. A DeCCE can contain multiple eREGs, and an eREG can have multiple REs within a PRB pair. Multiple eREGs for a DeCCE can be transmitted over multiple PRB pairs within the ePDCCH resource set. The first ePDCCH resource set is predefined as a distributed ePDCCH resource, and / or other ePDCCH resource sets may be configured as either a centralized ePDCCH resource or a distributed ePDCCH resource.

[0273] The number of PRB pairs per ePDCCH resource set may vary depending on system parameters. For example, the number of PRB pairs per ePDCCH resource set may vary depending on the system bandwidth or the number of RBs (e.g.,

[0274]

number

[0275] ),for example,

[0276]

number

[0277] It can be defined as a function such as: In this case, one or more of the following are applicable:

[0278]

number

[0279] And, however, N s This can be a fixed number or the number of eNB configurations, and the function of the number of PRB pairs per set may differ depending on the ePDCCH transmission, such as centralized and distributed ePDCCH, and / or the lookup table is

[0280]

number

[0281] According to N set It can be defined for N. set The value may differ from that shown in Table 8-4 below.

[0282] [Table 10]

[0283] In one embodiment, N set The fixed value of can be used in the common search space, but N set Multiple values ​​of can be used for the WTRU or UE-specific search space. set The multiple values ​​of can be changed depending on the system bandwidth, the number of subframes and / or the number of SFNs and / or at least one of the configured parameters via broadcasting or upper-layer signaling.

[0284] A subset of multiple ePDCCH resource sets may also be explicitly selected (e.g., using one or more instruction bits). For example, one or more instruction bits may be transmitted in the PDCCH region within the same subframe. In this embodiment, at least one of PCFICH or DCI in the PDCCH region may be transmitted for instruction bit transmission. PCFICH in the PDCCH region may be used to indicate how many ePDCCH resource sets may be used. In this case, the number of OFDM symbols for the PDCCH may be defined as following the same number indicated in PCFICH or configured via upper-layer signaling. DCI may be defined and / or transmitted in a common search space. DCI may include at least one of a number of ePDCCH resource sets and / or resource allocation indexes.

[0285] One or more instruction bits may be transmitted in the same subframe or a previous subframe within the PDSCH area. In this case, an instruction channel may be transmitted for instruction transmission. An instruction channel (e.g., ePCFICH) may be defined and / or transmitted at a specific location. The location for an instruction channel may be zero-power CSI-RS or a subset RE of zero-power CSI-RS. If a zero-power CSI-RS location may be used, a subset of the ePDCCH resource set may be valid within a duty cycle. An instruction channel may be defined in a first ePDCCH resource set. An instruction channel may be N set On the PRB pair, for example, N set A PRB pair may be transmitted if it can be used for the first ePDCCH resource set. The instruction channel is defined in a fixed arrangement within a subframe, and / or this arrangement may change depending on the cell ID and / or subframe number. The instruction channel is transmitted in subframe n-1, and / or the instruction information may be applied in subframe n.

[0286] A subset of multiple ePDCCH resource sets may be implicitly selected. For example, a specific DM-RS scramble sequence may be used for a subset of the ePDCCH resource set used for ePDCCH transmission in a subframe. A WTRU or UE can discover the ePDCCH resource set used for ePDCCH transmission in a subframe, for example, by using a DM-RS scrambled sequence. After the WTRU or UE has finished discovering the ePDCCH resource set, it can calculate a WTRU or UE-specific search space. The WTRU or UE can then begin blind detection within this WTRU or UE-specific search space.

[0287] Multiple ePDCCH resource sets may be implemented, which can be used interchangeably as ePDCCH regions, ePDCCH PRB sets, and / or ePDCCH sets. Each ePDCCH resource set has N non-overlapping properties. set It can contain 1 PRB pairs, however N set This can take one or more values. In this embodiment, each ePDCCH resource set can be configured as either an ePDCCH centralized transmit or an ePDCCH distributed transmit. set Alternatively, it may be configured via upper-layer signaling, predefined as a function of system parameters, and / or defined as a combination of system parameters and upper-layer signaling.

[0288] K set This ePDCCH resource set can also be configured for WTRU or UE, however, K set This can have a value of 2 or more. In this embodiment, N for each ePDCCH resource set set is, K set These ePDCCH resource sets are used independently when they can be configured, and N set It is constructed via upper-layer signaling, K setThis is indicated in the broadcasting channel (e.g., MIB, SIB-x), and / or K set This may vary depending on the SFN / subframe index.

[0289] N for each ePDCCH resource set set If it can be used independently, one or more of the following may apply: N set As long as a reasonable resource utilization can be presented, the frequency selection scheduling gain increases, and N is greater for concentrated transmissions. set N is larger for distributed transmission so that the frequency diversity gain is maximized. set It is defined as a function of the system bandwidth or other cell-specific parameters for at least one of the ePDCCH transmissions (e.g., centralized and distributed transmissions), for example, N set This is predefined for centralized transmission by the system bandwidth, while N set It is configured for distributed transmission via upper-layer signaling, and / or N set,1 and N set,2 Two N such as set However, K set It is constructed when is greater than 1, N set,1 This is used for ePDCCH resource sets configured as distributed transmissions, while N set,2 This can be used as a centralized transmission for all configured ePDCCH resource sets.

[0290] K set An ePDCCH resource set can be configured as a single ePDCCH resource set or as multiple ePDCCH resource sets. If a WTRU or UE can be composed of multiple ePDCCH resource sets, the WTRU or UE is K setIt is possible to assume =2. In this embodiment, when the WTRU or UE can be configured with a single ePDCCH resource set, the ePDCCH resource set can be configured as centralized or distributed ePDCCH transmission, and / or it can be assumed that the WTRU or UE can be configured such that the ePDCCH resource set can be configured as distributed transmission. When the WTRU or UE can be configured with multiple ePDCCH resource sets, at least one of the ePDCCH resource sets is configured as distributed ePDCCH transmission, the ePDCCH resource set is defined as the primary ePDCCH resource, and the other ePDCCH resource sets are defined as secondary ePDCCH resources, and / or N set may be different depending on the ePDCCH resource set. For example, the first set has N set =4, and the second set has N set =2.

[0291] In one embodiment, the ePDCCH resources can be configured and / or defined in different ways according to, or based on, the ePDCCH search space. For example, the ePDCCH common search space can be configured in a cell-specific manner, and the WTRU or UE-specific search space can be configured in a WTRU or UE-specific manner.

[0292] The ePDCCH common search space resources can be configured via at least one of the following. In one embodiment, a minimum set of PRB pairs can be configured at a specific time and / or frequency location in a predefined manner. For example, four PRB pairs or six PRB pairs are defined as the minimum set of PRB pairs for the common search space, and the four or six central PRB pairs in the downlink system bandwidth can be used for the common search space.

[0293] In addition, in subframes including PSS / SSS and / or PBCH, the location of the ePDCCH common search space may be adjacent to the central six PRB pairs if the downlink system bandwidth exceeds six PRB pairs. In this embodiment, four or six PRB pairs may be equally divided and located on either side of the central six PRB pairs.

[0294] PRB pairs for a common search space can also be extended in a WTRU or UE-specific manner. In this embodiment, the minimum set of PRB pairs can be considered as a first ePDCCH common search space set, and WTRU or UE-specific extensions to the common search space can be considered as a second ePDCCH common search space set. Thus, two ePDCCH common search space sets are configured, one of which can be configured in a cell-specific manner and the other in a WTRU or UE-specific manner. In such an embodiment, a subset of DCI formats that can be monitored in the common search space can be monitored in a cell-specific common search space, and the other in a WTRU or UE-specific common search space. For example, DCI formats 1A / 1B / 1C can be monitored in a cell-specific common search space, and DCI formats 3 / 3A can be monitored in a WTRU or UE-specific common search space. In addition, the WTRU or UE-specific common search space can be configured via upper-layer signaling or signaled via a broadcasting channel. Furthermore, in one embodiment, two common search space resource sets are configured, the first ePDCCH common search space resource set being predefined in fixed locations, while the second ePDCCH common search space resource set may be configured via a broadcasting channel such as an MIB or SIB-x.

[0295] A WTRU or UE-specific search space may be constructed via at least one of the following: In one embodiment, a WTRU or UE-specific ePDCCH resource set may be defined as a set of numerous PRBs. For example, one of the {2, 4, 8} PRBs may be constructed into a WTRU or UE-specific ePDCCH resource set via upper-layer signaling. In addition, bitmaps may be used to indicate PRB pairs that are constructed into a common search space. In one embodiment, up to two WTRU or UE-specific ePDCCH resource sets may be constructed per WTRU or UE, and the two WTRU or UE-specific ePDCCH resource sets may partially or completely overlap in PRB pairs.

[0296] Furthermore, PRB pairs for WTRU or UE-specific search spaces and PRB pairs for common search spaces may overlap. In this embodiment, one or more of the following are applicable: A second ePDCCH common search space resource set overlaps with a WTRU or UE-specific ePDCCH resource set, for example, the second ePDCCH common search space set may be either a WTRU or UE-specific common search space or a cell-specific common search space. If two ePDCCH common search space resource sets can be configured, the two ePDCCH common search space resource sets may completely or partially overlap each other.

[0297] This specification may describe an embodiment of resource configuration for TDD in an embodiment of a single DL carrier. In frame structure 2, several UL-DL subframe configurations and associated HARQ-ACKs and UL / DL authorizations may be defined, for example, to fully utilize UL / DL resources. Table 9 shows an example of a UL-DL subframe configuration that may tolerate various uplink-downlink traffic asymmetries depending on the network environment.

[0298] [Table 11]

[0299] In Table 9, "D" and "U" represent the downlink subframe and uplink subframe, respectively. "S" represents a special subframe that may be used when the subframe configuration can be changed from downlink to uplink, for example, as a guard time to allow the WTRU or UE to prepare to transmit a signal. The special subframe may include DwPTS, UpPTS, and GP, where the DwPTS and UpPTS periods may be the number of OFDM symbols for downlink and uplink transmissions, respectively. The remainder of the time excluding DwPTS and UpPTS can be considered as GP. Table 10 shows an example of a special subframe configuration.

[0300] [Table 12]

[0301] Since ePDCCH can be transmitted based on antenna ports 7-40, ePDCCH cannot be transmitted in a special subframe configuration. In such cases, the operation of the WTRU or UE for PDCCH reception may be as described herein. For example, the WTRU or UE may assume that ePDCCH may be restricted to transmission in a typical downlink subframe. The WTRU or UE may assume that the downlink control channel may be transmitted via a legacy PDCCH in a special subframe regardless of the PDCCH configuration. The WTRU or UE may assume that it receives an ePDCCH targeting a special subframe n in a downlink subframe nk, where k is defined according to the UL-DL subframe configuration and k may be defined as the downlink subframe closest to subframe n. If the WTRU or UE can be configured to receive ePDCCH, the WTRU or UE may skip blind decoding of the ePDCCH in a special subframe. ePDCCH and legacy PDCCH receivers are configurable, for example, as shown in the exemplary TDD UL-DL subframe configuration in Table 11, where "E" and "L" represent ePDCCH and legacy PDCCH, respectively.

[0302] [Table 13]

[0303] A WTRU or UE may assume that an ePDCCH may or may not be transmitted and / or monitored in a particular special subframe based on one or more of the following: For a downlink normal cyclic prefix (CP), an ePDCCH may be transmitted and / or monitored in the special subframe configurations {1, 2, 3, 4, 6, 7, 8} in Table 10 (for example, for such a TDD and / or downlink normal CP, it is not possible to transmit and / or monitor in configurations 0 and 5). Special subframe configurations on which an ePDCCH may be transmitted may be predefined as other than {1, 2, 3, 4, 6, 7, 8}. For example, an ePDCCH may be transmitted and / or monitored in a DwPTS containing more than m OFDM symbols, where m is 3, 8, 9, or 10. In addition, if special subframe configurations 0 or 5 may be used within a cell, the WTRU or UE behavior for PDCCH reception may be defined in one or more of the following ways: The WTRU or UE may assume that ePDCCH may not be transmitted and / or monitored in a special subframe (e.g., 0 or 5, which are not included in the special subframe configurations {1, 2, 3, 4, 6, 7, 8} described above), otherwise the WTRU or UE may monitor ePDCCH within a special subframe, and the WTRU or UE may assume that an ePDCCH targeting special subframe n is transmitted in subframe nk, where k may be defined as the downlink subframe closest to subframe n, and the WTRU or UE may assume that PDCCH may be transmitted via legacy PDCCH within a special subframe, and / or the WTRU or UE may follow the configuration of ePDCCH and predefined legacy PDCCH. If a special subframe configuration other than 0 and 5 may be used within a cell, the WTRU or UE may assume that ePDCCH may be transmitted in DwPTS. DwPTS There may be special subframes that are longer than [OFDM symbol]. DwPTSIt can be composed of upper layers. N DwPTS It may be fixed to 9 (for example, 19760·T for normal CP). s It is equal to 20480·T for extended CP. s (It can be considered equivalent to...)

[0304] When multiple component carriers can be configured in TDD mode, each component carrier can have a different UL-DL subframe configuration. For example, PCell and SCell can be configured with UL-DL configurations 1 and 2, respectively, as shown in Figure 17. Figure 17 shows one embodiment as an example of carrier aggregation with different TDD UL-DL configurations. In such a case, downlink subframes for PCell may not be available in subframes 3 and 8, but the WTRU or UE can anticipate receiving a PDSCH in SCell, and as a result, scheduling limitations may arise when cross-carrier scheduling can be activated because the WTRU or UE can receive a PDCCH in PCell. At least one of the WTRU or UE operations described herein can solve such problems and can be used when cross-carrier scheduling is activated. For example, the WTRU or UE can anticipate that a PDCCH may be transmitted in SCell when downlink subframes may not be available in PCell on the SCell downlink. A WTRU or UE can monitor for ePDCCH in SCell if there is no PDCCH reception, regardless of the PDCCH configuration. A WTRU or UE can monitor legacy PDCCH if the WTRU or UE can be configured to receive legacy PDCCH in PCell. A WTRU or UE can monitor legacy PDCCH or ePDCCH according to subframes that have a predefined PDCCH reception configuration. A WTRU or UE can assume that PDCCH may be transmitted in SCell when a downlink subframe or special subframe may not be available in PCell in a SCell downlink subframe. A WTRU or UE can continue to monitor PDCCH in special subframes if the special subframe configuration is not 0 or 5.If special subframe configuration 0 or 5 is used, the WTRU or UE can assume that the PDCCH may be transmitted via SCell. If multiple SCells are configured, the SCell with the lowest frequency can be considered a PCell for PDCCH reception.

[0305] Resource allocation in a multi-carrier system (e.g., across multiple DL carriers) (e.g., ePDCCH resource allocation) may be disclosed, provided, and / or used. In a multi-carrier system, resources for ePDCCH are defined in the PDSCH domain, and ePDCCH resources may be multiplexed with PDSCH in an FDM manner. ePDCCH resources may consist of one or more of the following:

[0306] ePDCCH resources may be restricted to configurations in primary cells (PCells) when cross-carrier scheduling can be activated. In such cases, a WTRU or UE may assume that ePDCCH may be restricted to transmission in PCells, and may restrict monitoring of ePDCCH reception to PCells. ePDCCH resources are not permitted in secondary cells (SCells). In addition, ePDCCH resources in SCells can be considered muted RBs from the perspective of the WTRU or UE so that the WTRU or UE can perform rate matching of RBs when PDSCH may be scheduled in RBs.

[0307] In addition, ePDCCH resources can be configured in a single cell when cross-carrier scheduling can be activated. Cells having ePDCCH resources (e.g., component carriers) can be configured by upper-layer signaling. Cells having ePDCCH resources (e.g., component carriers) may be predefined. For example, a broadcast channel (e.g., SIB-x) can indicate a cell. Component carriers having ePDCCH can be fixed or modified according to subframes and / or radio frames. If component carriers having ePDCCH can be modified, a WTRU or UE can implicitly deduce which component carrier has ePDCCH in a particular subframe and / or radio frame by using the SFN number.

[0308] An ePDCCH resource may be defined in a subset of component carriers that may be equal to or smaller than the configured component carriers for a particular WTRU or UE. The subset of component carriers may be composed of higher layers. In addition, the subset of component carriers may be predefined to include, for example, component carrier numbers and center frequencies. The subset of component carriers may also be dynamically changed from one subframe to another. The subset pattern may be predefined and / or associated with SFN numbers.

[0309] In one embodiment, ePDCCH and legacy PDCCH may be configured simultaneously. In such an embodiment, a subset of component carriers may be configured for ePDCCH, while other component carriers may be configured for legacy PDCCH. Thus, a WTRU or UE can monitor ePDCCH in component carriers configured for ePDCCH and legacy PDCCH in other component carriers.

[0310] The ePDCCH frequency diversity modes are interchangeable and not limited to ePDCCH distributed transmit, ePDCCH frequency diversity scheme, ePDCCH distributed mode, and / or mode-1. For ePDCCH frequency diversity modes (e.g., distributed mode, mode-1, etc.), resources for ePDCCH may be distributed across the system frequency bandwidth to obtain frequency diversity gain. ePDCCH resources for frequency diversity modes can be configured as described herein. For example, extended control channel elements (eCCEs) and / or extended resource group elements (eREGs) may be distributed across multiple downlink carriers (e.g., DL cells), and ePDCCH may be transmitted using {1, 2, 4, or 8} eCCEs, where N eCCEs eREGs This may include the following. Size-N may be predefined. If cross-carrier scheduling can be activated, the ePDCCH may be distributed across PCells, and the ePDCCH may also be distributed across multiple component carriers (e.g., DL carriers) in some other way. For eCCE aggregation, a WTRU or UE can aggregate eCCEs across multiple component carriers (e.g., DL carriers), for example, as shown in Figure 18. Figure 18 shows an exemplary eCCE aggregation across multiple carriers in distributed resource allocation. For eCCE-eREG mapping, the eREG may be distributed across multiple carriers. ePDCCH mode-1 may be configured within a central 5 MHz (e.g., 25 PRB) bandwidth.

[0311] The ePDCCH frequency selection mode is defined interchangeably and cannot be limited to ePDCCH centralized transmission, ePDCCH frequency selection mode, ePDCCH centralized mode, and / or mode-2. For the ePDCCH frequency selection mode (such as centralized mode, mode-2, and the like), resources for the ePDCCH can be arranged within one or two RBs according to the eCCE aggregation level so as to obtain frequency selection gain. The ePDCCH resources for the frequency selection mode can be configured as described in this specification. For example, eCCEs can be arranged within the same PRB pair when multiple eCCEs can be aggregated. eREGs arranged within the same PRB pair and / or adjacent PRB pairs can be aggregated to form eCCEs. ePDCCH mode-2 can be configured within a central 5 MHz (for example, 25 PRBs) bandwidth.

[0312] In a multi-component carrier system, ePDCCH mode-1 (such as ePDCCH frequency diversity mode) and / or ePDCCH mode-2 (such as ePDCCH frequency selection mode) can be configured as described in this specification. For example, a WTRU or UE can monitor ePDCCH mode-2 within the PCell and ePDCCH mode 1 within other configured cells when cross-carrier scheduling cannot be activated. A WTRU or UE can monitor ePDCCH mode 1 and / or ePDCCH mode-2 within the PCell when cross-carrier scheduling can be activated. A subset of ePDCCH mode-1 and / or ePDCCH mode-2 resources can be defined as ePDCCH mode-3 that can span multiple PRBs in the central frequency bandwidth.

[0313] The ePDCCH resource set can be defined in a cell such that N set PRB pairs for the ePDCCH resource set can be arranged in the cell. For example, K setIndividual ePDCCH resource sets can also be placed within a cell. For example, N set and / or K set This can be defined per cell when multiple component carriers may be used. Cells can also be used interchangeably as component carriers, PCells, and SCells. In this case, K in PCell set At least one of these sets is defined as ePDCCH distributed transmission, and / or K set This can be defined as centralized or distributed ePDCCH transmission in SCell.

[0314] In addition, the ePDCCH resource set is N for the ePDCCH resource set. set A PRB pair can be defined on multiple component carriers so that it can be placed on multiple component carriers. In this case, if the ePDCCH resource set can be configured as a distributed transmission, then N for the ePDCCH resource set set If the number of PRB pairs is placed on multiple component carriers and / or the ePDCCH resource set can be configured as a centralized transmit, then N for the ePDCCH resource set set Multiple PRB pairs can be placed within the same cell.

[0315] Extended Resource Element Groups (eREGs) may also be provided as described herein. A minimum resource unit for an ePDCCH may be defined and / or referred to as an eREG (Extended Resource Element Group). An eREG may be formed by a fixed number of REs. An eREG may be formed by a variable number of REs, the number of REs may vary by at least one of the following factors: the eREG number, the subframe number and / or subframe type (e.g., MBSFN subframe), the presence of zero-power CSI-RS configurations, PRS configurations, SSS / PSS, and / or similar factors. An eREG may be formed by available REs in a given time / frequency resource grid, such as an NxM RE in a PDSCH region that does not include zero-power CSI-RS and non-zero-power CSI-RS, SSS / PSS, and / or one or more (e.g., each or a subset) of PBCH, PRS, DM-RS, CRS, ePHICH, ePCFICH, and / or similar.

[0316] The time and / or frequency resource grid within the PDSCH region (NxM RE) for eREG can be provided and defined in at least one of the following ways: N and M indicate the frequency and time RE granularity, respectively, where N may be a fixed number in the range between 1 and 12 (in one embodiment, an exemplary fixed number for N may be 1 or 2), where N may be configurable by broadcasting (e.g., MIB or SIB-x) and / or RRC configuration, where N may differ within subframes for centralized transmission (ePDCCH mode-1) and distributed transmission (ePDCCH mode-2) (e.g., a smaller number of N is used for distributed transmission (N dist ) and / or a large number of N is used for centralized transmission (N local ), however N local >N dist (This is acceptable), M is usually 14-N in CP. PDCCH In the extended CP, 12-N PDCCH This can be done, however N PDCCHM is used in legacy PDCCH and may represent the number of OFDM symbols indicated by PCFICH within a subframe, and M is often defined as a fixed number such as 11 in CP and 9 in extended CP, and M may be configurable by broadcasting (e.g., MIB or SIB-x) and / or RRC configuration, and M may differ within a subframe for centralized transmission (ePDCCH mode-1) and distributed transmission (ePDCCH mode-2) (e.g., a smaller number of M is used for distributed transmission (M dist ) and a large number of M are used for concentrated transmission (M local ), however M local >M dist (This is acceptable.)

[0317] In one embodiment, an eREG is formed by a fixed or variable number of REGs, and a REG may be defined as four consecutive REs in a PDSCH area used in an ePDCCH as disclosed herein, but not for any other purpose. For example, one eREG may contain nine REGs, thereby making the eREG CCE-like (for example, which may simplify the development of standardization of terminology from the PDCCH used).

[0318] Figure 19 shows one embodiment as an example of the definition of eREG. For example, Figure 19 illustrates PRB pairs that can be used for ePDCCH transmission according to the number of antenna ports (e.g., ports 7-10 in the left part of Figure 19 and ports 7-8 in the right part of Figure 19). As shown in Figure 19, N=1 and M=11 can be used in subframes that do not include CSI-RS and PSS / SSS. The eREG spans both slots in the PRB pair, and the number of REs for the eREG may vary depending on the eREG number due to CRS and DM-RS. For example, eREG#n may contain 3 REs, and eREG#n+2 may contain 11 REs depending on the presence of DM-RS and CRS (e.g., as shown in the left part of Figure 19). Also, fully FDM-based eREG multiplexing can be used to flexibly utilize power for unused eREGs. For example, if eREG#n+7 is unavailable, the power can be reused to boost the power of eREGn+2.

[0319] In one embodiment, eREG resources may be defined in an interleaved manner to randomize RE locations so that channel estimation performance can be equal regardless of the eREG number. Thus, a WTRU or UE can receive eREGs based on virtual eREGs to physical eREG mapping rules.

[0320] A fixed number of eREGs can be defined for each PRB pair configured as an ePDCCH resource. For example, 16 eREGs can be defined for each PRB pair, regardless of the configuration such as the reference signal, subframe type, and CP length. The eREGs can be defined in an interlaced manner so that they are allocated cyclically for eREGs 0-15, with the REs (excluding those within the PRB pair) having higher frequencies. If 16 eREGs can be available for each PRB pair, then 16 × N set N eREGs set It may be available for ePDCCH resource sets having a number of PRB pairs.

[0321] In one embodiment, eREG subset blocking may be used to block a subset of eREGs in an ePDCCH resource set so that they are not used to form an eCCE. This may enable improved or better inter-cell interference coordination because non-overlapping eREGs can be used between adjacent cells.

[0322] Regarding eREG subset blocking, 16 × N set A subset of eREGs is indicated via upper-layer signaling, and this subset cannot be counted as an eREG. Thus, physical and virtual eREGs can be defined. Virtual eREGs can be used to form eCCEs. Therefore, the number of physical eREGs may be less than or equal to the number of virtual eREGs. A subset of eREGs can be predefined in the form of eCCEs, PRB pairs, and / or ePDCCH resource sets. Thus, indications may be based on eCCE numbers, PRB pair numbers, and / or ePDCCH resource set numbers. A subset of eREGs can be predefined as a table such that an index corresponds to the subset of eREGs. Bitmaps may be used to indicate a subset of eREGs that may be blocked.

[0323] A subset of eREG for blocking may be defined as a function of one or more system parameters, such as PCI, SFN number, and / or subframe number. In this embodiment, two or more subsets of eREG may be predefined by index, and / or the index of each subset may be configured as a function of at least one of the system parameters. For example, four subsets may be J sub For eREG #n, J is defined such that a subset of n is defined. sub It can be defined as law. subIf = 4, the subsets can be defined as follows: index-0: subset 0 = {eREG satisfying n mod 4 = 0}, index-1: subset 1 = {eREG satisfying n mod 4 = 1}, index-2: subset 2 = {eREG satisfying n mod 4 = 2}, and / or index-3: subset 3 = {eREG satisfying n mod 4 = 3}. If a subset of eREG for blocking can be defined as a function of one or more system parameters, the subset index can be implicitly indicated by at least one of the system parameters. For example, the subset index can be defined by the modulo operation of the cell-ID (e.g., index-i if i can be defined as cell-ID mod 4).

[0324] The start symbol for ePDCCH may be constructed as follows (for example, according to or based on the ePDCCH search space): For example, in one embodiment, the start symbol for a WTRU or UE-specific search space may be constructed or defined according to an associated common search space. The associated common search space may imply a common search space that is monitored in subframes from the WTRU or UE together with the WTRU or UE-specific search space. In addition, there may be different kinds (e.g., two kinds) of associated common search spaces, including, for example, the PDCCH common search space and the ePDCCH common search space.

[0325] According to one embodiment as an example, if the PDCCH common search space can be monitored in a subframe along with the ePDCCH WTRU or UE specific search space, one or more of the following may apply and / or be used or provided: The start symbol for the ePDCCH WTRU or UE specific search space is configured according to the transmit mode configured for the WTRU or UE. For example, if the WTRU or UE can be configured with legacy transmit modes (e.g., TM1-9), the WTRU or UE can calculate or determine the start symbol for ePDCCH regardless of the DCI format by following or using CIF in PCFICH. If the configured transmit mode can be a different transmit mode (e.g., TM-10 (CoMP transmit mode)), the WTRU or UE can receive notification and / or receive the ePDCCH start symbol via the upper layer regardless of the DCI format. In one embodiment, if the DCI format 2D is used, the ePDCCH start symbol may conform to or use the ePDCCH start symbol configured in the upper layer, otherwise the WTRU or UE may conform to or use CIF in PCFICH.

[0326] In addition, according to one embodiment as an example, if the ePDCCH common search space can be monitored in a subframe along with the ePDCCH WTRU or UE-specific search space, one or more of the following may apply and / or be provided and / or used: for example, ePDCCH; the start symbol for the WTRU or UE-specific search space may be the same as the start symbol for the ePDCCH common search space; furthermore, the start symbol for the ePDCCH WTRU or UE-specific search space may be configured as a function of the CFI value in the PCFICH and the start symbols for the ePDCCH common search space; the start symbol for the ePDCCH WTRU or UE-specific search space may be configured independently via upper-layer signaling regardless of the start symbol for the ePDCCH common search space; in addition, in one embodiment, the start symbol for the ePDCCH WTRU or UE-specific search space may be configured according to the transmission mode configured for the WTRU or UE. For example, based on the transmission mode and / or DCI format, a WTRU or UE may assume the same start symbol in the ePDCCH common search space, or may follow or use a start symbol value configured by upper-layer signaling. In particular, according to one embodiment, if a WTRU or UE may be configured in a legacy transmission mode (e.g., TM1-9), the start symbol in the WTRU or UE-specific search space may be the same as the start symbol in the ePDCCH common search space within the subframe, and if a WTRU or UE may be configured in a different transmission mode (e.g., TM10 (CoMP transmission mode)), the WTRU or UE may follow or use a start symbol value configured via upper-layer signaling.

[0327] The start symbol of the ePDCCH common search space may be further constructed or defined based on at least one of the following. According to one embodiment of the example, the WTRU or UE can implicitly detect the start symbol of the ePDCCH common search space by decoding the PCFICH within each subframe. In addition, the fixed start symbol is N pdcchThe number of OFDM symbols can be predefined by assuming that they can be occupied for legacy PDCCH. As such, the starting symbol for the ePDCCH common search space is N pdcch It may be +1. The number of OFDM symbols for PDCCH is N pdcch =0 may also be included. In a specific carrier type (for example, a new carrier type in which CRS cannot be transmitted in one or more subframes, e.g., not transmitted in subframes except for subframes containing PSS / SSS), the WTRU or UE has N OFDM symbols for PDCCH. pdcch It can be assumed that = 0. In such one embodiment, the common search space start symbol may be broadcast in the PBCH or SIB-x so that the start symbol indicated in the broadcasting channel is used for ePDCCH candidate demodulation in the ePDCCH common search space.

[0328] Extended control channel elements (eCCEs) can be described herein. For a given subframe i, an eCCE containing a number of eREGs is N eREGs (i) For each eREG j, the number of available REs is K REs (i,j) and the total number of available REs for one eCCE is

[0329]

number

[0330] Let's assume that this is the case.

[0331] A first category can be considered, in which case the number of available REs for the j-th eREG (e.g., K REs(i,j)) may vary due to several REs for other purposes, such as the reference signal, PDCCH, PSS / SSS, and similar, which may result in a change in the effective coding rate. One or more embodiments described herein may be used, for example, to maintain a similar effective coding rate for a given DCI payload.

[0332] For example, N eREGs The number of eCCEs can be fixed for each eCCE (for example, N eREGs =4), therefore, the starting point of the eCCE can be easily determined (for example, the starting points of the eCCEs may be the same). A fixed number of N for each eCCE. eREGs Since it may be used, the available REs may change. N fixed per eCCE eREGs To increase coverage by number, one or more of the following may be used and / or applied. For example, the transmit power per eCCE is defined as a function of the number of available REs, and the reference number of the RE per eCCE is N eCCE It may be so. For example, N eCCE = 36, and the number of available REs for a given eCCE is K REs If = 18, the additional transmit power added to the original transmit power is:

[0333]

number

[0334] It can be defined as follows: From the predefined power increase rules, the WTRU or UE can assume a power ratio between the reference signal and the ePDCCH RE for the demodulation process. eREGs The fixed number of can be defined separately according to the ePDCCH transmission type and / or search space type. For example, for centralized transmission, N eREGs =3 is used, and for distributed transmission, N eREGs =4 can be used. For concentrated transmission, a smaller N is used. eREGsThis can be used because beamforming gain and / or frequency-selective scheduling can be performed for centralized transmission. Distributed transmission may rely on frequency diversity gain through channel coding. eREGs Different values ​​of can be used for the common search space and the WTRU or UE-specific search space. For example, the common search space can be N eREGs =6 is used, and for the WTRU or UE-specific search space, N eREGs =4 may be used. The eCCE aggregation level in the ePDCCH search space varies depending on the subframe, and the aggregation level can be implicitly derived from the reference signal configuration for a particular subframe. The aggregation level is a positive integer number N AL It can be defined as a function of . For example, the search space for WTRU or UE is N AL Can be defined as {1, 2, 4, 8}. N within a specific subframe. AL If = 2, the WTRU or UE may need to monitor the ePDCCH at aggregation level 2, for example, {1, 2, 4, 8} = {2, 4, 8, 16}. AL This can be configured by the upper layer according to the subframe, or it can be implicitly defined according to the configuration of the subframe, including the reference signal, broadcast channel, and / or synchronization signal. AL This can be signaled by unused DCI bits transmitted over legacy PDCCH (for example, if it can be configured) or ePDCCH.

[0335] N is a variable number for each eCCE. eREGs However, it can be used, for example, to maintain a similar effective coding rate. Since the ePDCCH decoding candidates may be based on the eCCE level, the number of available REs for eCCE is a different number of N. eREGs It can be changed if it can be mapped. A larger number of N eREGs If each eCCE can be mapped, the effective coding rate can be lowered so that the channel coding gain increases as a result. That is, a larger number of N eREGsHowever, this can be mapped when puncturing of ePDCCH REs reduces the number of available REs per eCCE within a particular subframe. eREGs The variable number of can be defined as described herein. For example, N eREGs This is comprised of an eNB and may be communicated to a WTRU or UE via a broadcast channel and / or higher-layer signals. eREGs This can be configured independently for each subframe by duty cycle. For example, duty cycles of 10ms and 40ms can also be used. Two or more numbers N eREGs These are defined, and one of them can be selected according to the CSI-RS and ZP-CSI-RS configurations. For example,

[0336]

number

[0337] and

[0338]

number

[0339] These are predefined, and one of them can be selected as follows:

[0340]

number

[0341] This is used when CSI-RS and ZP-CSI-RS cannot be configured.

[0342]

number

[0343] This can be used when CSI-RS and / or ZP-CSI-RS can be configured.

[0344] Since the number of REs for eREG can be variable, the number of REs for eCCE can also be variable. eCCE can be defined differently depending on the ePDCCH transmission mode (i.e., distributed transmission and centralized transmission). For example, for centralized transmission, N eREGs =4 is used, and for distributed transmission, N eREGs =2 can be used in one embodiment, N eREGs This may be configurable by eNB via broadcasting (MIB or SIB-x) and / or upper-layer signaling.

[0345] In another embodiment, N eREGs This may vary depending on the subframe as described herein. eREGs The value may change if the subframe includes CSI-RS and / or zero-power CSI-RS. For example, N eREGs =4 is used in subframes that do not include CSI-RS and / or zero-power CSI-RS, N eREGs =6 may be used in subframes including CSI-RS and / or zero-power CSI-RS. eREGs The value is N when the overhead of the reference signal becomes higher. eREGs N may vary depending on the overhead of the reference signal, including zero-power CSI-RS, so that it becomes larger. For example, if the overhead of the reference signal can be less than 15% of the PDSCH area within the subframe, eREGs =4, when the overhead of the reference signal can be between 15% and 20% within the PDSCH region of the subframe, N eREGs =5, if the overhead of the reference signal can be between 20% and 30% within the PDSCH region of the subframe, then N eREGs =6, if the overhead of the reference signal can exceed 30% within the PDSCH area of ​​the subframe, if the overhead of the reference signal can be defined as "number of PDSCH REs / number of reference signals", and similarly, N eREGs= 5. In one embodiment, eREG and eCCE may be the same in a specific ePDCCH transmission mode, such as a concentrated transmission of ePDCCH.

[0346] N eREGs (i) We can consider another category where the number can be fixed for each eCCE, for example, so that the starting point of the eCCE is the same. To maintain the effective coding rate for the DCI payload, the number of available REs for the j-th eREG (e.g., K REs (i,j)) can be fixed for each eREG by transmitting ePDCCH over these REs for reference signals, PDCCH, and / or other purposes such as PSS / SSS, and by applying special precoding or mutual orthogonal patterns to both ePDCCH and non-ePDCCH. On the receiver side, after inverse precoding by WTRU or UE, the ePDCCH can be separated and a similar effective coding rate for a given DCI payload can be maintained.

[0347] N eREGs Assuming that the number of (i) changes for each eCCE, in order to maintain a similar effective coding rate for a given DCI payload, the j-th eREG (e.g., K RES Instead of fixing the number of available REs for (i,j)) on the receiver side, for example, for some of the eREGs as described above (e.g., after reverse precoding by WTRU or UE), the ePDCCH may be separated and a similar effective coding rate to the DCI payload may be maintained. The number of eREGs used to transmit ePDCCH and non-ePDCCH is:

[0348]

number

[0349] This can be adapted to ensure that it can be maintained for each CCE.

[0350] In addition, the eCCE definition may differ depending on the ePDCCH search space. In one such embodiment, the eCCE may be defined in the following ways for the WTRU or UE-specific search space and the common search space, respectively. For example, the eCCE definition for the WTRU or UE-specific search space may satisfy one or more of the following characteristics: Sixteen eREGs may be defined for each PRB pair, regardless of CP length and subframe type. Four or eight eREGs may be grouped to form an eCCE depending on the CP length and subframe type. Four eREGs may be grouped to form an eCCE for a normal CP with a normal subframe and / or a normal CP with a special subframe configuration {3, 4, 8}. In one embodiment, eight eREGs may be grouped to form an eCCE for a normal CP with a special subframe configuration {2, 6, 7, 9}, an extended CP with a normal subframe, and / or an extended CP with a special subframe configuration {1, 2, 3, 5, 6}. Furthermore, 4 or 8 eREGs may be grouped to form an eCCE depending on the CP length, subframe type, and / or common search space type. For example, in one such embodiment, if a WTRU or UE can monitor the PDCCH common search space within a subframe, the number of eREGs per eCCE for the WTRU or UE-specific search space is 8, but if the ePDCCH common search space can be monitored together with the ePDCCH WTRU or UE-specific search space, the number of eREGs per eCCE for the WTRU or UE-specific search space may be 4.

[0351] In addition, the eCCE definition for the common search space may satisfy one or more of the following characteristics: In one embodiment, 16 eREGs may be defined for each PRB pair, regardless of CP length and subframe type. Four or eight eREGs may also be grouped as the same as the WTRU or UE-specific search space. Furthermore, the four or eight eREGs may be grouped as the number of available REs (e.g., n ePDCCH) may be grouped to form an eCCE. In one such embodiment, the number of available REs may be counted in each subframe within a PRB pair that does not include PSS / SSS and / or PBCH. In addition, n ePDCCH If the value is less than a predefined threshold (e.g., 104), the eight eREGs are grouped together to form an eCCE; otherwise, four eREGs are used and / or may be grouped together.

[0352] Resource mapping may be implemented, which may include eREG-eCCE mapping. For example, an eCCE may be formed by one or more eREGs, and the group of eREGs may be formed differently according to the ePDCCH transmission mode (e.g., ePDCCH mode-1 and ePDCCH mode-2).

[0353] Figure 20 shows one embodiment of an example of eCCE-eREG mapping in ePDCCH using localized and distributed allocation (for example, when ports 7 and 8 may be used). For example, eREG is defined as shown in Figure 20, with N=1 and M=14-N PDDCH The following may be used. The eREG number may also be defined as at least one of the following: ePDCCH PRB(0~N tot (k)-1) in ascending order from the lowest frequency. However, N tot (k) represents the number of eREGs in subframe k, N tot =N eRB ×M REG It can be done as M REG This represents the number of eREGs in the PRB pair, as shown in Figure 20, and M REG =12 can be set to ePDCCH PRB(0~N tot (k)-1) in descending order from the lowest frequency. (0~N totRandom number generation within the range (k)-1) and mapping between virtual eREGs and physical eREGs can be defined. The eREG number can be (f,r), where f and r represent the subcarrier index and ePDCCH PRB number within the PRB pair, respectively. eREG #13 can be represented as eREG(1,1), and out-of-range numbers are 0-11 or 0-N. eRB It may be -1, and eREG# = r·12 + f.

[0354] For eCCE-eREG mapping in a shared PRB, at least one of the following methods may be used (e.g., consecutive assignment (mapping-1), interleaved assignment (mapping-2), hybrid assignment (mapping-3), and / or similar). In consecutive assignment (mapping-1), N eREGs Consecutive eREGs are aggregated with respect to the eCCE definition, and therefore the eCCE number is eCCE#n=eREGs#{n·N eREGs ,...,(n+1)·N eREGs It can be assigned as -1). For example, N eREGs When =4 and n=0, eCCE#0=eREGs#{0, 1, 2, 3}. In such one embodiment, the total number of eCCEs (M eCCE )teeth,

[0355]

number

[0356] It can be defined as follows. Figure 21 shows one such example (for example, Figure 21 shows one embodiment as an example of eCCE-eREG mapping by sequential allocation).

[0357] In interleaved assignments (e.g., mapping-2), N eREGs The interleaved eREGs are aggregated with respect to the eCCE definition, and therefore the eCCE number is eCCE#n=eREGs#{π(n·N)eREGs) ,...,π((n+1)·N eREGs Assigned as}(-1), π(·) is from 0 to M eCCE It can represent an interleaved sequence up to -1. An interleaved sequence π(·) is N eREGs It can be generated by a MeCCE block interleaver. N eREGs =4 and M eCCE If = 9, a 4x9 block interleaver can be defined as shown in Figure 22 (for example, Figure 22 shows an example of a block interleaver). In a block interleaver, the interleaved sequence can be generated by writing the sequence row first and reading the sequence column first. As such, the interleaved sequence from the block interleaver shown in Figure 22 is π = 0, 9, 18, 27, 1, 10, 19, 28, ..., 8, 17, 26, 35, which is

[0358]

number

[0359] It can be expressed as follows: The interleaved sequence π(·) has a length N tot The sequence is generated by a random sequence, which is predefined and may be known by both the WTRU or UE and the eNB. A permutation sequence can be further randomized using column permutations, for example.

[0360] In hybrid allocation (in mapping-3), a subset of consecutive sequences is reserved for centralized transmission, while other eREGs can be used for distributed allocation. For example, a subset of columns in a block interleaver is reserved for centralized transmission as shown in Figure 23 (for example, Figure 23 shows hybrid allocation by using a block interleaver), and eCCE#{4, 5, 6, 7} is used for centralized transmission, while other eCCEs can be used for distributed allocation. To generate a centralized eCCE, N eREGs A sequence of eCCEs can be used. From this operation, N eREGs N consecutive distributed allocation-based eCCEs are eREGs It can be a centralized eCCE. To generate both centralized and distributed eCCEs, eNB is M eCCE Define a distributed eCCE for N, and for a centralized eCCE for N eREGs n consecutive or closed eCCEs can be reserved. Columnar permutations can be used in the distributed allocation portion to further randomize the permutation sequence. From the hybrid allocation shown in Figure 23, eCCEs can be defined as shown in Figure 24. Figure 24 shows one embodiment as an example of the coexistence of centralized and distributed eCCEs.

[0361] For eCCE-eREG mapping in another PRB, eREG can be defined independently for centralized and distributed transmission. For example, LeREG (centralized eREG) may be defined from 0 to N-1, and DeREG (distributed eREG) may be defined from 0 to K-1, with consecutive assignments (e.g., mapping-1) used for LeREG and / or interleaved assignments (e.g., mapping-2) used for DeREG. For eCCE-eREG mapping in another PRB, eREG may be defined for the limited case of distributed transmission, and eCCE may be the minimum resource unit for centralized transmission.

[0362] The eCCE-eREG configuration can be at least one of the following: an eCCE assignment (e.g., mapping-1, mapping-2, or mapping-3) is predefined, the mapping method may differ by subframe index and / or SFN, the mapping method may be configurable by upper-layer signaling, or the mapping method may differ by ePDCCH PRB pairs and / or similar. According to one embodiment as an example, N eRB However, if it may be available for ePDCCH transmission, N eRB In this embodiment, N eRB This can be defined separately for each mapping method.

[0363] If 16 eREGs are available for each PRB pair, and one eCCE can be defined by a group of four eREGs, then four eCCEs can be defined for each PRB pair for ePDCCH centralized transmission, since an eCCE can be defined within a PRB pair for centralized transmission. In one embodiment, four consecutive eREGs from the 16 eREGs can be grouped to form a centralized eCCE. The eCCE-eREG mapping rules may be the same for each PRB pair configured as an ePDCCH resource. Four consecutive eREGs within a PRB pair with the same starting point, regardless of the cell, can be used. For example, the eREG-eCCE mapping rule for each cell could be eCCE(n)={eREG(k), eREG(k+1), eREG(k+2), eREG(k+3)}, eCCE(n+1)={eREG(k+4), eREG(k+5), eREG(k+6), eREG(k+7)}, eCCE(n+2)={eREG(k+8), eREG(k+9), eREG(k+10), eREG(k+11)}, and / or eCCE(n+3)={eREG(k+12), eREG(k+13), eREG(k+14), eREG(k+15)}. Four consecutive eREGs within a PRB pair with different starting points can be used. The starting point of eREG can be defined either by configuration via upper-layer signaling or as a function of at least one of the system parameters, such as the physical cell ID and subframe / SFN number. In the following example, the offset can be configured via upper-layer signaling or defined as a function of at least one of the system parameters. In one example, eCCE(n)={eREG((k+i+offset)mod16), i=0,1,2,3}, eCCE(n+1)={eREG((k+4+i+offset)mod16), i=0,1,2,3}, eCCE(n+2)={eREG((k+8+i+offset)mod16), i=0,1,2,3}, and / or eCCE(n+3)={eREG((k+12+i+offset)mod16), i=0,1,2,3}.

[0364] In addition, in one embodiment, four mutually exclusive eREGs from among the 16 eRGEs can be grouped to form an eCCE, where the four eCCEs are defined for each PRB pair, and each eCCE can contain four mutually exclusive eREGs. The four mutually exclusive eREGs can be selected by using one or more embodiments described herein to form the eCCE. For example, interleaved mapping can be used for eREG-eCCE mapping. The eREG-eCCE mapping may be based on a block interleaver (e.g., interlaced mapping). Examples of eREG-eCCE mappings include eCCE(n)={eREG(k), eREG(k+4), eREG(k+8), eREG(k+12)), eCCE(n+1)={eREG(k+1), eREG(k+5), eREG(k+9), eREG(k+13)}, eCCE(n+2)={eREG(k+2), eREG(k+6), eREG(k+10), eREG(k+14)}, and / or eCCE(n+3)={eREG(k+3), eREG(k+7), eREG(k+11), eREG(k+15)}. Interleaved mappings can be used for eREG-eCCE mappings based on random interleaving. Interleaved sequences can be predefined or constructed via upper-layer signaling. If the interleaved sequences for each eCCE within the PRB pair are defined as π1={0, 4, 8, 12}, π2={1, 5, 9, 13}, π3={2, 6, 10, 14}, and π4={3, 7, 11, 15}, then π j、 j=0, 1, 2, 3 is eCCE(n+j), eCCE(n+j)={eREG(k+π j (1)), eREG(k+π j (2)), eREG(k+π j (3)), eREG(k+π j (4))} may be used to form the interleaved sequence. The interleaved sequence may be defined as a function of at least one of the system parameters, including the physical cell ID, subframe, and / or SFN number.

[0365] Antenna port mapping can also be implemented and / or used. For example, antenna ports {107, 108, 109, 110} may be interchangeable with antenna ports {7, 8, 9, 10}, since antenna ports {7, 8, 9, 10} or a subset thereof may be used for ePDCCH transmission and have the same time and / or frequency locations with orthogonal cover codes. In one embodiment, antenna ports 7-10 may be used for eREG and / or eCCE demodulation, so antenna port mapping may be defined according to eREG / eCCE locations. Figure 25 shows one embodiment as an example of antenna port mapping for eREG / eCCE. As shown in Figure 25, eREG / eCCE may be mapped onto antenna ports. Figure 25 also shows that the number of available antenna ports may vary depending on the configuration.

[0366] Number of available antenna ports (N) port ) can be defined as described herein. port This can be configured semi-statically for subframes and ePDCCH PRB pairs. Therefore, the WTRU or UE is configured when the ePDCCH is N port It can be assumed that transmission is not possible at the RE position for antenna ports within the range. For example, N port If = 4, then 24 RE positions in the PRB pair in Figure 25 are reserved, and ePDCCH cannot be transmitted at these RE positions. port If = 2, 12 RE positions are reserved, and ePDCCH can be transmitted at those RE positions for ports 9 and 10. port This can be predefined as 4 so that the WTRU or UE can assume that the ePDCCH cannot be transmitted at the RE position relative to the four antenna ports. port This can vary depending on the ePDCCH PRB pair number. For example, N port =2 is used in ePDCCH PRB #0, Nport =4 can be used in ePDCCH PRB #1. port The ePDCCH PRB pair may be configured differently depending on the ePDCCH transmission mode. If ePDCCH PRB #{0, 1, 2} can be used for centralized transmission, then N port =4 is used for these ePDCCH PRBs, N port =2 can be used for ePDCCH PRB for distributed transmission, or vice versa. port This may be configured separately for each ePDCCH PRB pair and / or ePDCCH transmit mode.

[0367] In addition, antenna ports may be assigned to eREG / eCCE based on or in accordance with at least one of the following: A WTRU or UE may assume that eREG / eCCE associated with the WTRU or UE within the “same PRB pair” may be transmitted on the same antenna port. For example, if eREG / eCCE #{n,n+1, n+2, n+3} may be used for a WTRU or UE, the WTRU or UE may assume that the eREG may be transmitted on one antenna port (e.g., port-7). Antenna ports may be configured semi-statically via upper-layer signaling. In such one embodiment, antenna ports may be the same for a WTRU or UE across each ePDCCH PRB pair. Antenna ports may be defined as the lowest eREG / eCCE index within the same PRB pair. For example, if eREG / eCCE #{n, n+3, n+6, n+9} can be used for a WTRU or UE, then the antenna port for eREG / eCCE #{n} can be used for other eREG / eCCEs. Antenna ports can be defined as functions of C-RNTI. For example, modulo 4 or 2 of C-RNTI can indicate the assigned antenna port for a WTRU or UE. In one such embodiment, the antenna ports may be the same for a WTRU or UE across ePDCCH PRB pairs. If arithmetic modulo 4 can be used, a WTRU or UE can assume that one of antenna ports 7-10 is used for the WTRU or UE, otherwise one of antenna ports 7-8 may be used. Antenna ports are defined as functions of C-RNTI with CDM groups, which can be composed of higher layers. For example, a WTRU or UE may be configured by the upper layer to monitor an ePDCCH in CDM group 2 where ports 9 and 10 are available, and a C-RNTI to the WTRU or UE may instruct it to use port 9 after a modulo 2 operation.For example, C-RNTI can indicate which orthogonal cover codes can be used between [+1 +1] and [+1 -1] within a CDM group, and eNB can select the CDM group. Antenna ports can be defined as a function of C-RNTI and PRB pair index. For example, modulo 4 or 2 of (C-RNTI + PRB index) may indicate the assigned antenna port for a WTRU or UE.

[0368] A WTRU or UE may assume that eREGs / eCCEs associated with the WTRU or UE at a “Precoding Resource Granularity (PRG)” may be transmitted on the same antenna port. For example, if a WTRU or UE demodulates multiple eREGs in a PRG, the WTRU or UE may assume that the same antenna port may be used for the eREGs in the PRG. The WTRU or UE may assume that the same precoder may be used for the antenna ports within the PRG. The PRG size may vary depending on the system bandwidth. Table 12 shows an embodiment of an example PRG size for an ePDCCH.

[0369] [Table 14]

[0370] The PRB size is 1 for the system bandwidth candidate, and the WTRU or UE can assume that each antenna port in the PRB size uses the same precoder, for example, so that channels spanning the antenna ports are interpolated. For example, if antenna ports 7 and 9 within the PRG size range can be used for ePDCCH demodulation at the WTRU or UE receiver, the WTRU or UE can assume that antenna ports 7 and 9 can be transmitted on the same virtual antenna port so that estimated channels from ports 7 and 9 are interpolated. An antenna port can be defined as the lowest eREG / eCCE index within the PRG range. For example, if eREG / eCCE #{n, n+8, n+16, n+24} can be used by the WTRU or UE, then the antenna port for eREG / eCCE #{n} can be used for other eREG / eCCEs. An antenna port can be further defined as a function of C-RNTI. For example, modulo 4 or 2 of C-RNTI can indicate the assigned antenna port for the WTRU or UE. In one embodiment, the antenna port may be the same for the WTRU or UE across the ePDCCH PRB pair, even in this case. In addition, the antenna port can be defined as a function of the C-RNTI and PRG index. For example, the modulo 4 or 2 of (C-RNTI + PRG index) may indicate the assigned antenna port for the WTRU or UE.

[0371] A WTRU or UE may also assume that eREGs / eCCEs associated with the WTRU or UE in the same PRB pair are transmitted on different antenna ports, and that the antenna ports for each eREG / eCCE may be defined based on or in accordance with at least one of the following methods described herein. For example, eREG / eCCE locations may be mapped one-to-one on antenna ports according to the number of available antenna ports. If four antenna ports may be available in a PRB pair, eREGs #{n, n+1, n+2} may be mapped on port-7, eREGs #{n+3, n+4, n+5} may be mapped on port-8, eREGs #{n+6, n+7, n+8} may be mapped on port-9, and the rest may be mapped on port-10. If that port is available, eREGs #{n, n+1, n+2, ..., n+5} may be mapped on port-7, and the other eREGs may be mapped on port-8. The associated antenna port number can be defined according to the eREG / eCCE location and aggregation level for the WTRU or UE. For example, if eREGs #{n, n+1, n+2} are mapped to port-7 and the three REGs can be demodulated together, then eREGs #{n+3, n+4, n+5} can be mapped to port-8. If eREGs #{n, n+1, n+2, n+3, n+4, n+5} can be demodulated together, then port-7 is used, and port-8 can no longer be the antenna port for eREGs{n+3, n+4, n+5}. eREG / eCCE locations can be mapped one-to-one to antenna ports according to the number of available antenna ports. The association rules between eREG / eCCE and antenna ports can be configured by the eNB. For example, if four antenna ports may be available in a PRB pair, eREG / eCCE #{n, n+1, n+2} may be mapped to port-7, and eREG / eCCE #{n+3, n+4, n+5} may be mapped to port-8 for a WTRU or UE.For another WTRU or UE, eREG / eCCE #{n, n+1, n+2} may be mapped to port-8, and eREG / eCCE #{n+3, n+4, n+6} may be mapped to port-7.

[0372] Association rules can be configured according to at least one of the following embodiments. For example, an eNB can configure rules that associate WTRU or UE-specific upper layers via signaling. Association rules can be configured as a function of an RNTI (e.g., C-RNTI) so that a WTRU or UE implicitly obtains the rules it associates. In such a case, for example, even a single WTRU or UE may have different association rules depending on the RNTI type. In one example, a DCI associated with a C-RNTI can use association rule 1, and another DCI associated with an SPS-RNTI can use association rule 2. Modulo operations can be used to define association rules such that the number of association rules (e.g., n_association) is used in the modulo operation as a function of the RNTI. An association rule for a DCI associated with a particular RNTI can be defined as association rule number = (RNTI) mod n_association. Association rules can be configured as a function of an RNTI in combination with other parameters, which may include one or more of the cell ID, subframe number, and / or SFN. Association rules may be fixed for the common search space, but configurable for the WTRU or UE-specific search space.

[0373] In one embodiment, a WTRU or UE may assume that a single antenna port configured via upper-layer signaling can be associated with each eREG / eCCE in centralized transmission. A predefined one-to-one mapping between eREG / eCCE and antenna ports can be used for distributed transmission.

[0374] Resource element (RE) mapping (e.g., puncturing and / or rate matching) may be implemented and / or used as described herein. For example, the modulation symbols of DCI after channel coding may be mapped onto ePDCCH REs. Since ePDCCH REs may be located within RE locations, mapping rules may be defined in terms of the coding chain. In embodiments of the coding chain, RE mapping rules may include puncturing and / or rate matching as disclosed herein. Puncture and / or rate matching may be implemented as follows:

[0375] Encoded bits (c 1、 ..., c N ) is the output of a channel encoder that takes a DCI payload as input, where the channel encoder may be a channel code such as a turbo code, convolutional code, or Reed-Müller code. The encoded bits may include 16 bits masked with CRC appending, for example, RNTI. Modulation symbols (x1, ..., x M ) can be the output of the mapper. The output of the mapper may be such that the encoded bits are modulated to a modulation scheme such as BPSK, QPSK, 16QAM, 64QAM, and similar. Depending on the modulation scheme, the modulation symbol sequence M may be less than or equal to N. In RE mapping, the modulation symbol x 1、 ..., x M The ePDCCH RE is mapped, for example, by frequency first or by time first, however puncturing implies or may specify that if the RE in the ePDCCH may be occupied by another signal, the modulation symbol for the RE will not be transmitted. For example, x k If (k≦M) is mapped to a specific ePDCCH RE according to the mapping rule, and the ePDCCH RE can be occupied for another purpose, then x k It was not sent, and the next mapping is x k+1It can start from. Rate matching is performed when the next mapping to an available RE that is not being used for another purpose is x k It can be implied or specified that transmission may begin from a certain point. For example, if there are six modulation symbols {x1, x2, x3, x4, x5, x6} to be transmitted, and the ePDCCH REs for x2 and x4 may be occupied for other purposes, {x1, x3, x5, x6} may be transmitted if a puncturing scheme is used, and {x1, x2, x3, x4} may be transmitted if rate matching is used.

[0376] Puncturing schemes may lose organized bits when convolution and / or turbo coding may be used, so in one embodiment, decoding performance may be worse than rate matching schemes when coding speeds may be high. Puncturing can provide robustness when occupied RE information cannot be synchronized between the eNB and the WTRU or UE. Channel decoding may fail when occupied RE information is not synchronized between the eNB and the WTRU or UE compared to rate matching schemes. Puncturing and rate matching rules based on the purpose of occupied RE can be implemented and / or used.

[0377] In one embodiment, the rate matching scheme can be used for a cell-specific or group-specific RE that is occupied and configured, while the puncturing scheme can be used for a WTRU or UE-specific RE that is occupied and configured. In one example of rate matching, the RE may be occupied by a PDCCH (or PDCCH region), CRS (cell-specific reference signal), ePDCCH DM-RS, PRS, PSS / SSS (primary sync signal / secondary sync signal), and / or PBCH. In puncturing, the RE may be occupied by a CSI-RS and a zero-power CSI-RS.

[0378] Rate matching and puncturing rules can be defined according to the search space. For example, a common search space can use a puncturing scheme, while a WTRU or UE-specific search space can use a rate matching scheme, making the common search space more robust to errors in occupied RE information, and vice versa. In one example of rate matching, each RE may be occupied by other signals in the WTRU or UE-specific search space. In puncturing, each RE may be occupied by other signals in the common search space. In addition, in one example of rate matching, each RE may be occupied by other signals in the common search space. In puncturing, each RE may be occupied by other signals in the WTRU or UE-specific search space.

[0379] According to one embodiment of the example, rate matching and puncturing rules may be defined according to the ePDCCH transmission scheme or technique, such as centralized and / or distributed transmission. For example, rate matching may be applied to each RE occupied by other signals in the eCCE for centralized transmission, and puncturing may be applied to each RE occupied by other signals in the eCCE for distributed transmission, or vice versa.

[0380] Rate matching and puncturing rules can also be defined by semi-static and dynamic signals. In one example of rate matching, RE may be occupied by fixed cell-specific signals including CRS, PSS / SSS, and / or PBCH. In puncturing, RE may be occupied by semi-static or dynamic configurations including PDCCH, CSI-RS, DM-RS, and / or PRS. In one example of rate matching, RE may be occupied by semi-static or dynamic configurations including PDCCH, CSI-RS, DM-RS, and / or PRS. In puncturing, RE may be occupied by fixed cell-specific signals including CRS, PSS / SSS, and / or PBCH.

[0381] In one embodiment, rate matching and puncturing rules may also be defined according to the ePDCCH search space. For example, rate mapping and puncturing rules may be defined differently depending on whether the search space is a WTRU or UE-specific search space or a common search space (e.g., different rate matching and / or puncturing rules may apply to a WTRU or UE-specific search space than those for a common search space). For a WTRU or UE-specific search space, REs are configured as WTRU or UE-specific search space resources of the ePDCCH, and REs that may conflict with PDCCH, CSI-RS, zero-power CSI-RS, and DM-RS may be rate-matched here and there.

[0382] In the common search space, one or more of the following are applicable. For example (with respect to REs configured as ePDCCH common search space resources), REs located at CRS locations can be rate-matched here and there. In one such embodiment, the CRS port number can be fixed to 4 regardless of the CRS port number detected by the PBCH. As such, the WTRU or UE can assume that REs located at CRS ports 0-3 can be rate-matched here and there when decoding the ePDCCH common search space. In addition, in such embodiments, the WTRU or UE can be used according to and / or the number of CRS ports detected by the PBCH for rate-matching of REs located at CRS ports.

[0383] In addition, for common search spaces where REs can be configured as ePDCCH common search space resources, REs located in CSI-RS and zero-power CSI-RS can be punctured. Similarly, if a WTRU or UE can be configured with CSI-RS and / or zero-power CSI-RS, REs located in these locations can be punctured.

[0384] In one example embodiment, with respect to the common search space and PDCCH, if the WTRU or UE can monitor the PDCCH common search space together with the ePDCCH common search space, the WTRU or UE can perform rate matching here and there for REs located at PDCCH locations. Otherwise, the WTRU or UE can perform rate matching here and there for REs located at OFDM symbols under the ePDCCH common search space start symbol.

[0385] According to one embodiment, a search space design may be provided and / or used as described herein. For example, a search space for a single DL carrier may be disclosed. A WTRU or UE may monitor the ePDCCH via blind decoding so that multiple blind decoding attempts are used per subframe. Candidates for blind decoding attempts from the perspective of the WTRU or UE may henceforth be referred to as the search space. At least one of two types of search spaces may be defined for the ePDCCH, such as a WTRU or UE-specific search space (USS) and a common search space (CSS). The common search space in the ePDCCH can transmit DCIs related to UEs in a group and / or cell, such as broadcasting / multicasting, paging, and group power control. The WTRU or UE-specific search space can transmit DCIs for uplink and / or downlink unicast traffic.

[0386] From the perspective of a WTRU or UE, there can be at least two search spaces, and the location of a search space can be defined using at least one of the following configurations: In one configuration (e.g., Configuration 1), both USS and CSS are provided or used in the legacy PDCCH, and the WTRU or UE can monitor USS and CSS. In such a configuration, the WTRU or UE can monitor USS and / or CSS in the legacy PDCCH region. This configuration may be the same as or similar to the Release 8 PDCCH configuration. In an additional configuration (e.g., Configuration 2), both USS and CSS are provided or used in the ePDCCH, and the WTRU or UE can monitor USS and CSS (e.g., the WTRU or UE can monitor USS and / or CSS within the ePDCCH region). In yet another configuration (e.g., Configuration 3), USS is provided or used in the legacy PDCCH, and CSS is provided or may be used in the PDCCH (e.g., a WTRU or UE can monitor CSS in the legacy PDCCH area and / or USS in the ePDCCH area). In addition, in one configuration (e.g., Configuration 4), USS is provided or used in the ePDCCH, and CSS is provided or used in the legacy PDCCH, and for example, a WTRU or UE can monitor CSS in the legacy PDCCH area and USS in the ePDCCH area. In addition (e.g., Configuration 4), CSS may be shared with the legacy UE. In this case, CCEs 0 through 15 may be used as CSS in the legacy PDCCH area. In Configuration 4, CSS may be defined in a different way. For example, CCEs 16 through 31 in the legacy PDCCH may be used as CSS for a WTRU or UE configured by the ePDCCH for USS. In another exemplary configuration (e.g., configuration 5), USS is provided or used in ePDCCH, and CSS may be split between legacy PDCCH and ePDCCH.In an additional configuration (e.g., configuration 6), the USS is split into legacy PDCCH and ePDCCH, with CSS provided or used in the ePDCCH. In another configuration (e.g., configuration 7), both the USS and CSS can be split into legacy PDCCH and ePDCCH. In configuration 8, the USS is split into legacy PDCCH and ePDCCH, with CSS provided or used in the legacy PDCCH.

[0387] A search space configuration may be defined based on, or in accordance with, at least one of the following: A single configuration may be predefined, with details of the configuration information broadcast in the MIB and / or SIB-X. A configuration may be predefined so that a WTRU or UE receives the configuration when broadcasting information in at least one of the MIB or SIB. A configuration may be RRC configured so that a WTRU or UE can request that the search space be modified according to RRC signaling. A configuration may also be modified according to the SFN and / or subframe number so that a WTRU or UE can implicitly know the configuration in each subframe (e.g., per-subframe configuration information may be notified by broadcasting or RRC signaling, and / or per-subframe configuration information may be predefined (e.g., subframes #0 and #5)).

[0388] The eCCE aggregation levels are defined as the same as those for legacy PDCCH, with aggregation levels {1, 2, 4, 8} defined, and the number of blind decoding attempts may be 44 in total without uplink multi-antenna transmission (e.g., DCI format 4). The number of REs for eCCE may be variable, unlike CCE in legacy PDCCH, and the coding speed for ePDCCH can vary depending on the aggregation level, which may result in variations in ePDCCH coverage.

[0389] Additional aggregation levels may be added to the previous aggregation levels {1, 2, 4, 8} for ePDCCH to enable finer ePDCCH link adaptation, as shown in Table 13. For WTRU or UE-specific search spaces, aggregation levels {3, 5, 6, 7} are added, with {6} being added, for example, for common search spaces.

[0390] [Table 15]

[0391] The number of aggregation levels can be increased, but the number of blind decoding attempts can be kept the same as before to avoid increasing the complexity of the WTRU or UE receiver. To maintain the number of blind decoding attempts, a subset of aggregation levels may be monitored in subframes.

[0392] [Table 16]

[0393] In addition, a WTRU or UE may monitor a subset of aggregation levels according to the subset of ePDCCH candidates shown in Table 14. A subset for ePDCCH monitoring may be based on or relating to at least one of the following: a subset of ePDCCH aggregation levels may be composed of broadcasting and / or upper-layer signaling; the overhead of reference signals within the ePDCCH resource may implicitly constitute a subset; the subset may be composed in different ways according to the ePDCCH transmission mode (e.g., mode-1 and mode-2); the subset may be composed in different ways according to the ePDCCH PRB number; and / or similar configurations may be made.

[0394] The number of ePDCCH candidates per aggregation level may vary depending on the DCI format, ePDCCH resource set, and / or subframe. For example, if aggregation level 1 is more frequently used for DCI formats 0 / 1A, then more ePDCCH candidates may be used for aggregation level 1 compared to aggregation level 2. More ePDCCH candidates may be used for DCI format 2C compared to aggregation level 1.

[0395] Table 14-1 shows an example of a DCI format-dependent ePDCCH candidate set where the number of ePDCCH candidates varies depending on the aggregation level, and where different DCI formats may be used.

[0396] [Table 17]

[0397] The WTRU or UE can attempt to decode eight ePDCCH candidates with aggregation level 1 when the WTRU or UE can monitor DCI format 0 / 1A. If the WTRU or UE can monitor DCI format 2C, the WTRU or UE can attempt to decode four ePDCCH candidates.

[0398] The number of ePDCCH candidates at each aggregation level may vary depending on the DCI format within the WTRU or UE-specific search space. In addition, in one embodiment, the common search space may have the same number of ePDCCH candidates at each aggregation level, regardless of the DCI format.

[0399] The number of ePDCCH candidates for aggregation levels {1, 2, 4, 8} can be configured via broadcasting and / or upper-layer signaling. In one cell, the ePDCCH candidates may be configured as {6, 6, 2, 2} (e.g., the same for legacy PDCCH), while in another cell, for example, {2, 10, 2, 2} can be configured as ePDCCH candidates. The ePDCCH candidates for an aggregation level can be configured independently depending on the DCI format or group of DCI formats. To reduce signaling overhead, multiple sets of ePDCCH candidates for an aggregation level can be defined by indicator bits, for example, as shown in Table 14-2.

[0400] [Table 18]

[0401] In some embodiments, one or more sets of ePDCCH candidates may have the same number of ePDCCH candidates as legacy PDCCHs, such as {6, 6, 2, 2} for a WTRU or UE-specific search space and / or {4, 2} for a common search space. One or more of these sets may not have ePDCCH candidates for a common search space. In this case, the WTRU or UE can monitor PDCCH candidates as a common search space. One or more of these sets may include subsets of aggregation levels that cannot have candidates. For example, {8, 8, 0, 0} may be used so that aggregation levels 4 and 8 are not supported in the search space in this case. The total number of blind decoding attempts may be kept the same.

[0402] Definitions of ePDCCH candidates may also be provided and / or used as described herein. A WTRU or UE may be configured to monitor ePDCCH in a common search space and / or a WTRU or UE-specific search space. In one embodiment, ePDCCH candidates that a WTRU or UE can monitor within a subframe may be defined according to the ePDCCH transmission type.

[0403] Candidate ePDCCHs for a WTRU or UE-specific search space can be defined for concentrated and / or distributed transmissions of ePDCCHs as follows, where N eCCE,p,k This can represent the total number of eCCEs that may be available for the ePDCCH resource set p. The WTRU or UE-specific search space for the ePDCCH resource set p.

[0404]

number

[0405] teeth,

[0406]

number

[0407] It can be defined as, however, i=0, ..., L-1,

[0408]

number

[0409] and

[0410]

number

[0411] That is the case.

[0412]

number

[0413] Y may represent the number of ePDCCH candidates for aggregation level L in the ePDCCH resource set p. Y may be the hash function for the ePDCCH resource set p. p,k Y p,k =( A·Y k-1 ) can be defined by modD, however Y p,-1 =n RNTI ≠0, A=39827, D=65537, and

[0414]

number

[0415] That is the case.

[0416] In addition, the ePDCCH candidates for the centralized ePDCCH resource set are offset by a value (K) to distribute the ePDCCH candidates across as many PRB pairs as possible. offset ) can be defined as follows. The same WTRU or UE-specific search space formula can be used for both centralized and distributed ePDCCHs. In this embodiment, for example, the WTRU or UE-specific search space for an ePDCCH resource set p composed of centralized ePDCCHs

[0417]

number

[0418] teeth,

[0419]

number

[0420] It can be defined as: K for the ePDCCH resource set p offset,pThis can be configured via upper-layer signaling in a way specific to the WTRU or UE. offset,p This includes the aggregation level (L), the ePDCCH candidate index (m'), and the total number of available eCCEs N. eCCE,k , and / or the number of ePDCCH resource sets K set It can be defined as a function of at least one of the parameters.

[0421] In another example, the offset by the number of ePDCCH candidates and the aggregation level is:

[0422]

number

[0423] It can be expressed as, however, with an offset (K offset,p ) can be defined as a function of the number of ePDCCH candidates (m'). K offset,p An example of the definition may be the following embodiment. In such an example embodiment (for example, the example formula), m' and m can be used interchangeably.

[0424] According to one example embodiment,

[0425]

number

[0426] This can be used when multiple ePDCCH resource sets may be used. In one such embodiment, the offset for ePDCCH resource set p is:

[0427]

number

[0428] It can be defined as, however, N eCCE,k,p and

[0429]

number

[0430] This can be considered specific to the ePDCCH resource.

[0431] In another example embodiment,

[0432]

number

[0433] It can be used, however, Δ offset,p This can represent an offset value for the ePDCCH resource set p. For example, the first ePDCCH resource set can have an offset value of zero (i.e., Δ offset,p-0 (=0), the second ePDCCH resource set can have a predefined value (i.e., Δ offset,p-1 =3). In an additional embodiment, Δ for the second set offset,p It can be defined by at least one of the following: Δ offset,p It is constructed via upper-layer signaling, Δ offset,p This is the aggregation level and / or the number of PRBs configured for the ePDCCH resource set (i.e., the number of eCCEs N). eCCE,k,p It is implicitly constructed as a function of ) and / or Δ offset,p This can be configured as a function of the subframe number and / or aggregation level.

[0434] In another example, the offset (for example, according to the ePDCCH candidate number and aggregation level) is the offset (k offset,p ) may be defined as a function of the ePDCCH candidate number, etc.

[0435]

number

[0436] It can be expressed as follows. In this embodiment, the offset is

[0437]

number

[0438] It can be defined as follows. In addition, there is an offset value Δ specific to the ePDCCH resource set. offset,p This is Δ for the first ePDCCH resource set. offset,p=0 =0 and Δ for the second ePDCCH resource set offset,p=1 It can be defined as at least one of the following: =λ, where λ is a predefined positive integer number (e.g., λ=3) and Δ offset,p It is constructed via upper-layer signaling, Δ offset,p This is implicitly configured as a function of the aggregation level and the number of PRBs configured for the ePDCCH resource set, and / or Δ offset,p This can be configured as a function of the subframe number and / or aggregation level.

[0439] According to additional examples,

[0440]

number

[0441] It can be used (for example, it can be defined for an offset), however, Φ offset n is an offset value for cross-carrier scheduling, and CI This can be the carrier indicator field value. Φ offset Φ can have different numbers according to the ePDCCH resource set, in which case Φ offset is Φ offset,p It can be replaced by...

[0442]

number

[0443] It can be used. Φ offset (For example, in one such embodiment) can be defined by at least one of the following: Φ offset n is a predefined value, CI This can be the carrier indicator field value, Φ offset It is constructed via upper-layer signaling, Φ offset It is implicitly configured as a function of the aggregation level and the number of PRBs configured for the ePDCCH resource set, Φ offset It is configured as a function of the subframe number, carrier indicator value, and / or aggregation level, and / or Φ offset teeth

[0444]

number

[0445] It can be defined as, however,

[0446]

number

[0447] This can be considered as the number of ePDCCH candidates for aggregation level L in the ePDCCH resource set p.

[0448] In another example,

[0449]

number

[0450] You can use Φ offset Δ is the offset value for cross-carrier scheduling.offset,p This is the offset relative to the EPDCCH resource set p, and n CI This can be the carrier indicator field value. Or

[0451]

number

[0452] It can be used. Φ offset and Δ offset,p (For example, in one such embodiment) can be defined by at least one of the following: Φ offset Δ is a predefined value, offset,p It is configured as a function of the ePDCCH resource set index, Φ offset Δ is a predefined value, offset,p It is constructed as a function of the aggregation level, carrier indicator value, and / or aggregation level, and / or Φ offset and Δ offset,p Both can be constructed via upper-level signaling.

[0453] In other examples, K offset These can be predefined in the table. Table 14-3 shows an example of how offset values ​​are defined by aggregation level. The exact offset values ​​may vary. The exact offset values ​​may change depending on the system configuration and / or ePDCCH resource set configuration.

[0454] [Table 19]

[0455] Alternatively, the hash function is not used for centralized ePDCCH transmission, and ePDCCH candidates for a centralized ePDCCH resource set may be defined by at least one of the following characteristics: WTRU or UE-specific search space

[0456]

number

[0457] teeth,

[0458]

number

[0459] It can be defined as follows, where i=0, ..., L-1, m'=m+M (L) ·n CI , and m=0, ...,M (L) τ is -1, and τ is defined as a fixed value in a predefined way, or constructed via upper-layer signaling in a way specific to the WTRU or UE, and / or τ can be defined as a function of the ID of the WTRU or UE. For example, τ = nRNTI That is the case.

[0460] The search space may contain multiple ePDCCH resource sets. Multiple ePDCCH resource sets may have a large number of usable PRB pairs, and / or this number may be fixed regardless of system bandwidth, cell ID, and / or subframe number, or it may be variable depending on system bandwidth, cell ID, and / or subframe number. The same number of eCCEs may be available in ePDCCH resource sets. The number of eCCEs available in an ePDCCH resource set may be fixed regardless of system bandwidth, cell ID, and / or subframe number. The number of eCCEs available in an ePDCCH resource set may be variable depending on system bandwidth, cell ID, and / or subframe number. The number of eCCEs available in an ePDCCH resource set may be tied to the number of PRB pairs for the ePDCCH resource set, such as an integer multiple of the number of PRB pairs for the ePDCCH resource set (for example, 2 or 4 eCCEs per PRB pair may be used in twice the number of PRB pairs). In addition, the number of eCCEs available in the ePDCCH resource set can be changed depending on the configuration.

[0461] In another embodiment, the number of available eCCEs may vary depending on the ePDCCH resource set. For example, the number of eCCEs in an ePDCCH resource set may vary depending on the number of PRB pairs configured for the ePDCCH resource set (e.g., N). est ) and can be defined as a function of at least one of the system configurations, including CP length, subframe type, dual mode (TDD or FDD), and / or carrier type (e.g., legacy carrier or other carrier type). In this case, the same N est If the number and CP length can be used for the ePDCCH resource set, a larger number of available eCCEs is defined in non-legacy carrier types compared to legacy carriers, and non-legacy carrier types may implicitly indicate that the carrier does not have legacy downlink control channels and CRSs in the downlink subframes (e.g., PDCCH, PHICH, and PCFICH).

[0462] Multiple ePDCCH resource sets or a subset of ePDCCH resource sets from a configured set may be used for a WTRU or UE-specific search space. For example, K set If three ePDCCH resource sets can be defined, then two ePDCCH resource sets (e.g., sets 1 and 2) can be used as ePDCCH resources for a particular WTRU or UE. Multiple PDCCH resource sets can have at least one of the following characteristics:

[0463] According to one example embodiment, K setn ePDCCH resource sets are defined, and each ePDCCH resource set may contain the same number of eCCEs (e.g., 16 eCCEs). The number of eCCEs can be fixed or variable depending on the system parameters. The eCCE index can be defined from 0 to the total number of eCCEs in a given number of ePDCCH resource sets. For example, if three ePDCCH resource sets are defined (e.g., K set =3) If each ePDCCH resource set may contain 16 eCCEs, the eCCE index can be defined as (eCCE#0, ..., eCCE#15) for the first ePDCCH resource set, and as (eCCE#16, ..., eCCE#31) and (eCCE#32, ..., eCCE#47) for the second and third ePDCCH resource sets, respectively. Total number of eCCEs N eCCE is, K set ·K eCCE And K eCCE This represents the number of eCCEs in the ePDCCH resource set, N eCCE =K set ·K eCCE This can be done. The total number of eCCEs in subframe k is N eCCE,k This may be shown by: In one embodiment, a search space specific to the WTRU or UE

[0464]

number

[0465] teeth,

[0466]

number

[0467] It can be defined as follows, where i=0, ..., L-1, m'=m+M (L) ·n CI , and m=0, ...,M (L) -1 Y k is Yk =( A·Y k-1 ) can be defined by modD, however Y -1 =n RNTI ≠0, A=39827, D=65537, and

[0468]

number

[0469] It can be done this way.

[0470] eCCE indexes can also be defined for each ePDCCH resource set. For example, three ePDCCH sets may be defined (e.g., K set =3) If each ePDCCH resource set contains 16 eCCEs, the eCCE index is (eCCE#0, ..., eCCE#K) for the first, second, and / or third ePDCCH resource set. eCCE It can be defined as -1). A WTRU or UE-specific search space can be defined for each ePDCCH resource set, N eCCEk =K eCCEk In this case, one or more of the following are applicable. For example, a WTRU or UE-specific search space can be defined for each ePDCCH resource set. An ePDCCH candidate for an aggregation level can be divided into two or more ePDCCH resource sets. An ePDCCH resource set can be used for a WTRU or UE-specific search space. A subset of an ePDCCH resource set can be used for a specific WTRU or UE-specific search space. In one embodiment, this subset is n RNTI It can vary depending on the circumstances.

[0471] Table 14-4 shows an example where two ePDCCH resource sets (e.g., n=0 and 1) are used for a WTRU or UE-specific search space, and ePDCCH candidates can be evenly divided between the two ePDCCH resource sets.

[0472] [Table 20]

[0473] WTRU or UE-specific search space for the ePDCCH resource set p

[0474]

number

[0475] teeth,

[0476]

number

[0477] or

[0478]

number

[0479] It can be defined as Y. p,k A is defined for each ePDCCH resource set and can have different numbers according to the ePDCCH resource set index p within the same subframe. A can be defined with different numbers according to the ePDCCH resource set index. In an exemplary embodiment, Y p,k is subframe number n RNTI and / or can be defined as a function of the ePDCCH resource set index p. In addition, Y p,k Y p,k =( A p ·Y p,k-1 ) can be defined by modD, however Y p,-1 =n RNTI ≠0, D=65537, and

[0480]

number

[0481] A p A is defined as a prime number, p=0 If =39827, then the 0th set may be considered to be the first ePDCCH resource set. p=0 (p>0) can be a prime number less than or greater than 39827. For example, A p=0 =39827 and A p=1 = 39829.

[0482] In addition, Y p,k Y p,k =( A·Y p,k-1 +Δ offset,p ) can be defined by modD, however, Δ offset,p Δ may be an offset relative to the ePDCCH resource set p. In such one embodiment, Δ offset,p It can be defined as at least one of the following: a value configured in the upper layers, a predefined number that can be used for offsets specific to the ePDCCH resource set, e.g., DELTA offset,p=0 =0 and DELTA offset,p=1 = λ, where λ can be a predefined number (e.g., 3) and / or an offset that can be randomly generated (e.g., Δ offset,p=0 = 0 and / or Δ offset,p=1 =λ, where λ is an offset that can be defined as a function of one or more of the following: subframe number and / or WTRU or UE-ID (e.g., C-RNTI), and / or ePDCCH resource type (e.g., distributed or centralized), number of PRBs, aggregation level, ePDCCH candidate number, and / or number of eCCEs.

[0483] According to one example embodiment, Y p,k Y p,k =( A p ·Y p,k-1 +Δ offset,p ) can be further defined by mod D, however, Δ offset,pThis can be considered an offset specific to the ePDCCH resource set.

[0484] A WTRU or UE-specific search space can be defined on multiple ePDCCH resource sets, and the location of an ePDCCH candidate for blind detection can be defined as a function of the ePDCCH resource set number and the eCCE number.

[0485] In addition, an eCCE index is defined for one or more ePDCCH resource sets, and the associated ePDCCH resource sets may differ depending on the ePDCCH transmission type and / or eCCE aggregation level. In this case, one or more of the following are applicable: For example, an eCCE index may be defined for each ePDCCH resource set in at least one of the following cases: A low eCCE aggregation level, such as 1 and / or 2, is used, and / or the ePDCCH resource set is configured as a distributed transmission. An eCCE index may be defined on two or more ePDCCH resource sets in at least one of the following cases: A high eCCE aggregation level, such as 8 or higher, is used, and / or the ePDCCH resource set is configured as a centralized transmission. One or more subsets of an ePDCCH resource set may be indicated from an instruction channel (e.g., extended PCFICH) in each subframe.

[0486] For multiple ePDCCH resource sets, each ePDCCH resource set can be independently configured as either centralized or distributed ePDCCH transmission. If multiple ePDCCH resource sets can be configured for a WTRU or UE, a subset of the configured ePDCCH resource sets may be configured for centralized transmission, and the remainder of the ePDCCH resource sets may be configured for distributed transmission. ePDCCH candidates are defined differently for centralized and distributed ePDCCH resource sets, different hash functions are used for centralized and distributed ePDCCH resource sets, and / or K set A set of ePDCCH resource sets is defined, and each ePDCCH resource set can have a different number of eCCEs (for example, 16 eCCEs in the primary set and 32 eCCEs in the secondary set).

[0487] If ePDCCH candidates can be defined differently for centralized and distributed ePDCCH resource sets, one or more of the following may apply and / or be used: hash function (Y k) This is used for the distributed ePDCCH resource set, with an offset value K offset A hash function may be used for centralized ePDCCH resource sets, while a hash function dependent on the ePDCCH resource set may be used for distributed ePDCCH resource sets. If different hash functions may be used for centralized and distributed ePDCCH resource sets, the legacy hash function may be used for distributed ePDCCH resource sets, while another hash function may be defined for centralized ePDCCH resource sets.

[0488] Embodiments of antenna port mapping based on search space are also provided and / or used as described herein. For example, identical or similar ePDCCH candidates in a WTRU or UE-specific search space may have different antenna ports and / or scramble IDs, while a common search space may have the same antenna ports and / or scramble IDs. In such embodiments, if a WTRU or UE-specific search space may be defined as {eCCE#n,...,eCCE#n+k}, the operation of the WTRU or UE monitoring the ePDCCH may include one or more of the following: Antenna ports for eCCEs in a WTRU or UE-specific search space may be configured in a WTRU or UE-specific manner. For example, one WTRU or UE may demodulate eCCE#n on antenna port 7, and another WTRU or UE may demodulate eCCE#n on antenna port 8. The antenna configuration may be communicated to the WTRU or UE via upper-layer signaling or implicitly derived from the RNTI. Antenna ports for eCCEs within a WTRU or UE-specific search space can be blind-decoded within that WTRU or UE-specific search space. For example, a WTRU or UE-specific search space may include eCCE#n by antenna port 7 and eCCE#n by antenna port 9. The WTRU or UE can also demodulate (e.g., iteratively demodulate) the same resource (eCCE#n) by antenna ports 7 and 9.

[0489] According to additional embodiments, DM-RS scrambling sequences may be provided and / or used. For example, for demodulation of ePDCCH, antenna ports {7, 8, 9, 10} may be used for channel estimation, and equivalent but {107, 108, 109, 110} may be used. In this case, the DM-RS sequence for the antenna ports is:

[0490]

number

[0491] It can be defined as, however, sequence initialization c init teeth,

[0492]

number

[0493] It can be defined as, however,

[0494]

number

[0495] (X ID ,n SCID ) can be used interchangeably. init Regarding the definition, one or more of the following may apply: Different scrambling sequences may be used for the same ePDCCH resource, and / or a single scrambling sequence may be used for ePDCCH resources within a cell.

[0496] In one embodiment, different scrambling sequences are used on the same ePDCCH resource (e.g., PRB pair) according to the WTRU or UE and / or blind decoding trials, thereby increasing, for example, the multi-user multiplexing gain. For example, one WTRU or UE can demodulate eCCE#n with a scrambling sequence, and another WTRU or UE can demodulate eCCE#n with a different scrambling sequence, and the scrambling sequences can be associated with a demodulation reference signal (e.g., an antenna port). Another example is that one WTRU or UE can demodulate eCCE#n with scrambling sequences A and B. Candidate scrambling sequences can be defined as follows: Candidate scrambling sequences are n SCID and / or X ID Defined by, the candidate scramble sequence is {n SCID =0, n SCIDDefined as {=1}, and / or scramble sequence candidates are {(X1, n SCID =0), (X2, n SCID =0),(X1, n SCID =1),(X2, n SCID It is defined as =1), where X1 and X2 may be different numbers defined within the range of 0 to the cell ID number.

[0497] A single scramble sequence, where cell-specific parameters are X ID The number used is fixed to n SCID It can also be used for ePDCCH resources within a cell, as is the case with X ID This can be defined as a physical cell ID or constituted by upper-layer signaling. SCID It can be fixed as either 0 or 1.

[0498] If multiple ePDCCH resource sets can be defined, the scramble sequence can be used for each ePDCCH resource set or across ePDCCH resource sets. For example, the scramble sequence can be defined for each ePDCCH resource set. In addition, X ID X may be defined for each ePDCCH resource set so that multiple scramble sequences are used without dynamic instruction. In one such embodiment, if ePDCCH resource sets can be configured, X is associated with each ePDCCH resource set. ID It can also be constructed as n. SCID can be fixed as 0 or 1. Two X ID However, it is configured via upper-layer signaling, and each ePDCCH resource set is configured according to its configuration. ID You can use one of the following: Fixed predefined X ID X can be used in the common search space to demodulate the ePDCCH candidate in the common search space using WTRU or UE. ID This is used for ePDCCH candidates within a WTRU or UE-specific search space, and XID This may differ depending on the ePDCCH resource set, or it may be the same for all ePDCCH resource sets. ID If two or more of these can be used with multiple ePDCCH resource sets, the PDSCH associated with the ePDCCH may be received in a subframe in at least one of the following ways: WTRU or UE is the same X used in the ePDCCH associated for PDSCH demodulation. ID X can be used and / or used in the associated ePDCCH ID Regardless of that, WTRU or UE is n in the associated DCI. SCID X as indicated by ID You can use n SCID If = 0, X1 may be used. Otherwise, X2 may be used. WTRU or UE is the same X used in ePDCCH associated with PDSCH demodulation. ID If available, the scramble sequence may be aligned with the PDSCH and the associated ePDCCH so that the Coordinated Multipoint Transmission (CoMP) operation is applied to the ePDCCH.

[0499] X ID The use of may depend on the configured transmit mode for the PDSCH. For example, if the WTRU or UE is configured for non-CoMP operation, a single X ID However, it is used for the ePDCCH resource set, X ID This can be defined as a physical cell ID. However, if the WTRU or UE can consist of a CoMP operation, then two or more X ID Each of the ePDCCH resource sets is used, X ID It can be constructed independently by X. ID This may or may not be the same for the ePDCCH resource set.

[0500] In additional embodiments, DM-RS sequences may be defined in different ways according to or based on the ePDCCH search space. For example, depending on the ePDCCH search space, one or more of the following may apply and / or be used and / or provided: In one embodiment, WTRU or UE-specific DM-RS sequences may be configured for the WTRU or UE-specific search space, and cell-specific DM-RS sequences may be used for the common search space. Sequence initialization c for the WTRU or UE-specific search space init teeth,

[0501]

number

[0502] Defined as, n EPDCCH ID It is configured via a higher layer for each ePDCCH resource set,

[0503]

number

[0504] This can be a fixed number (for example, 0, 1, or 2). For the ePDCCH common search space,

[0505]

number

[0506] It is defined as a function of the physical cell ID,

[0507]

number

[0508] can be a fixed number (for example, 0, 1, or 2). For example,

[0509]

number

[0510] This may be the physical cell ID or equal to it.

[0511] In another embodiment, both the WTRU or UE-specific search space and the common search space may consist of either a WTRU or UE-specific DM-RS sequence or a cell-specific DM-RS sequence.

[0512] In addition, in one embodiment, if multiple (e.g., two) ePDCCH resource sets are configured for an ePDCCH WTRU or UE-specific search space, and (e.g., one) ePDCCH resource set can be used for an ePDCCH common search space, then one or more of the following may apply and / or be used and / or provided: for example, sequence initialization c for a WTRU or UE-specific search space. init This can be defined in a WTRU or UE-specific manner for each ePDCCH resource set when ePDCCH WTRU or UE-specific resources cannot overlap with ePDCCH common search space resources. In one such embodiment, sequence initialization c for the WTRU or UE-specific search space is defined. init teeth,

[0513]

number

[0514] Defined as, n EPDCCH ID It is configured via a higher layer for each ePDCCH resource set,

[0515]

number

[0516] x can be a fixed number (for example, 0, 1, or 2).

[0517] For ePDCCH WTRU or UE-specific search space resources that may completely and / or partially overlap with ePDCCH common search space resources, sequence initialization c for the WTRU or UE-specific search space init This may be defined the same as the ePDCCH common search space DM-RS sequence initialization. In such an embodiment, if cell-specific DM-RS sequences can be used in the ePDCCH common search, then WTRU or UE-specific DM-RS sequences for ePDCCH resource sets overlapping with the common search space can use cell-specific DM-RS sequences. In addition, in such an embodiment, sequence initialization c for the WTRU or UE-specific search space init This occurs when the WTRU or UE-specific search space cannot overlap with the ePDCCH common search space.

[0518]

number

[0519] Defined as, however

[0520]

number

[0521] It is configured via a higher layer for each ePDCCH resource set,

[0522]

number

[0523] x can be a fixed number (for example, 0, 1, or 2).

[0524] In addition, in one example embodiment, sequence initialization c for a WTRU or UE-specific search space is performed. init This occurs when the WTRU or UE-specific search space may overlap with the ePDCCH common search space.

[0525]

number

[0526] Defined as, however

[0527]

number

[0528] It is defined as a function of the physical cell ID,

[0529]

number

[0530] can be a fixed number (for example, 0, 1, or 2). For example,

[0531]

number

[0532] This may be the physical cell ID or equal to it.

[0533] The design of the search space (e.g., in a CA or for multiple DL carriers) can be implemented as described herein. For example, a search space associated with multiple DL carriers can be implemented. In the ePDCCH resource, a common search space and a WTRU or UE-specific search space can be defined. The search space can be defined in a multi-carrier system in one or more of the following ways:

[0534] The common search space is restricted to being defined within a PCell, and / or WTRU or UE-specific search spaces can be defined across multiple component carriers. A WTRU or UE can restrict monitoring of the common search space to the PCell and WTRU or UE-specific search spaces in the corresponding PCell / SCell. In the common search space, a Carrier Indicator Field (CIF) can indicate the corresponding component carrier in DCI format. Component carriers from which an ePDCCH can be received in a WTRU or UE-specific search space are considered corresponding component carriers. Figure 26 shows an exemplary common search space definition, which may be restricted, for example, to the legacy PDCCH region within a PCell. The WTRU or UE-specific search spaces that can be defined within a PCell, and the common search space, can be defined across multiple component carriers.

[0535] The common search space is defined within the PCell, and the WTRU or UE-specific search space may be defined in at least one of the SCells. The common search space is defined in the legacy PDCCH in the PCell, and / or the WTRU or UE-specific search space may be defined in the ePDCCH in at least one of the SCells.

[0536] In one embodiment, a PCell may be defined independently of a legacy PDCCH and / or an ePDCCH. In this case, there may be cells-0, cell-1, and cell-2, where cell-0 is configured as a PCell for the legacy PDCCH and / or cell-2 is configured as a PCell for the ePDCCH. The PCell for the ePDCCH may be defined by an offset relative to the PCell of the legacy PDCCH.

[0537] Both WTRU or UE-specific search spaces and common search spaces may be restricted to being defined within a PCell. In addition, both WTRU or UE-specific search spaces and common search spaces can be defined across multiple component carriers.

[0538] According to one embodiment as an example, two ePDCCH modes, e.g., an ePDCCH frequency diversity mode (e.g., ePDCCH mode-1) and an ePDCCH frequency selection mode (e.g., ePDCCH mode-2), can be defined and / or used. In addition, ePDCCH mode-1 can achieve frequency diversity gain such that the common search space is limited to being defined by ePDCCH mode-1.

[0539] In some embodiments, a WTRU or UE-specific search space may be defined in one or more of the following ways: The WTRU or UE-specific search space can be defined by either ePDCCH mode-1 or ePDCCH mode-2. The ePDCCH mode for a WTRU or UE-specific search space may be configured by RRC signaling so that the WTRU or UE restricts its monitoring to ePDCCH mode-1 or ePDCCH mode-2 according to its configuration. In addition, the ePDCCH mode for a WTRU or UE-specific search space may be configured according to the SFN so that the WTRU or UE can know from the SFN number which ePDCCH mode can be defined in the subframe. In another example embodiment, the ePDCCH mode for a WTRU or UE-specific search space may be configured according to the component carrier. For example, ePDCCH mode-1 may be configured for a PCell, and ePDCCH mode-2 may be configured for a secondary cell (SCell). A WTRU or UE can monitor ePDCCH in a PCell using ePDCCH mode-1 and ePDCCH mode-2 for SCell. The ePDCCH mode for each component carrier can be configured by upper-layer signaling.

[0540] Furthermore, ePDCCH mode-1 and ePDCCH mode-2 can be defined within the same subframe. In blind decoding, the WTRU or UE can decode half in ePDCCH mode-1 and the other half in ePDCCH mode-2. The portion of ePDCCH modes that the WTRU or UE can blind decode varies depending on the subframe and / or may be comprised of eNBs. Table 15 shows:

[0541]

number

[0542] and

[0543]

number

[0544] This shows an example of how many ePDCCH candidates can be represented for ePDCCH mode-1 and mode-2, respectively. A WTRU or UE can monitor one ePDCCH mode configured by the eNB via upper-layer signaling.

[0545] [Table 21]

[0546] If cross-carrier scheduling can be activated, a PDCCH may be restricted to transmitting within a PCell to monitor the PCell in the limited case that a WTRU or UE receives a PDCCH. Since ePDCCH is defined, the behavior of a WTRU or UE may be defined in one or more of the following ways when cross-carrier scheduling can be activated: Legacy PDCCHs and / or ePDCCHs may be restricted to transmitting within a PCell according to their PDCCH configuration. If an eNB can configure a legacy PDCCH for a WTRU or UE, the WTRU or UE may be restricted to monitoring the legacy PDCCH in a PCell. Otherwise, the WTRU or UE may monitor the ePDCCH within a PCell. The WTRU or UE may assume that each PDCCH may be transmitted within a PCell.

[0547] In addition, PCell is defined independently for legacy PDCCHs and ePDCCHs, such as PCell_pdcch and PCell_epdcch, where PCell_pdcch and PCell_epdcch represent PCell for legacy PDCCHs and ePDCCHs, respectively. A WTRU or UE can monitor PCell_epdcch for a set of component carriers configured for an ePDCCH and PCell_pdcch for other component carriers configured for a legacy PDCCH. PCell_pdcch and PCell_ePDCCH may be the same component carrier.

[0548] Interference randomization, as disclosed herein, can also be implemented and / or used. For example, the frequency location of an ePDCCH can be changed from one subframe to another, randomizing interference between ePDCCHs from multiple cells.

[0549] For such interference randomization, a WTRU or UE can employ various behaviors. For example, the behavior of a WTRU or UE monitoring ePDCCH can be defined as follows: If cross-carrier scheduling can be activated, the WTRU or UE can monitor ePDCCH in a specific cell within a subframe, and the index-specific cell can be implicitly derived from the SFN number and / or radio frame. If cross-carrier scheduling cannot be activated, the WTRU or UE can monitor ePDCCH in each of the configured component carriers, however, the ePDCCH resource may be changed within a cell from one subframe to another depending on the SFN number and / or radio frame.

[0550] According to one embodiment as an example, WTRU or UE receiver processing may be used and / or implemented. For example, PDSCH decoding processing time relaxation may be performed. In such an embodiment, FDD (e.g., having frame structure 1) and / or TDD (e.g., having frame structure 2) may be implemented and / or used. For example, TBS is (I TBS ,N PRB The transport block size is defined by (see, for example, Non-Patent Document 1), and (I TBS ,N PRB The number of ) can become larger, however, 0 ≤ I TBS ≤26 and ≤1 ≤N PRB The value is ≤110. Since ePDCCH can be transmitted in the PDSCH region, a WTRU or UE receiver may lose decoding time for a HARQ-ACK transmission that could be used to transmit in uplink subframe n+4 after receiving a PDSCH in downlink subframe n. Uplink signal T TA (0≦T TA Since it can send ≤0.67[ms] earlier, time advance (T TA) can reduce PDSCH decoding time. The larger the transport block size, the more PDSCH processing time is used, so a larger TBS can reduce PDSCH processing time. TA The value is relatively large and may be restricted when ePDCCH can be used. The TBS restriction may be used according to one or more of the following:

[0551] In the example method, the TBS restriction may be used as follows (for example, according to one or more of the following): For example,

[0552]

number

[0553] and

[0554]

number

[0555] teeth,

[0556]

number

[0557] It can be defined in the case of, however,

[0558]

number

[0559] and

[0560]

number

[0561] This may represent the maximum and limited number of PRBs for the TBS index. As such, WTRU or UE is

[0562]

number

[0563] Larger TBSs can be assumed not to be sent to WTRUs or UEs.

[0564]

number

[0565] and

[0566]

number

[0567] This is a WTRU or UE-specific time-advance value (T) in a way specific to WTRU or UE. TA It can be defined as a function of ). Maximum TBS

[0568]

number

[0569] too,

[0570]

number

[0571] It can be expressed as follows, where Δ can be the TBS table.

[0572] In addition,

[0573]

number

[0574] is, formula

[0575]

number

[0576] (where γ is the weighting coefficient) and / or

[0577]

number

[0578] (where δ is the weighting coefficient) It can be defined as a function of the time-advancing value in at least one of the following cases.

[0579] moreover

[0580]

number

[0581] is, formula

[0582]

number

[0583] (where γ is the weighting coefficient) and / or

[0584]

number

[0585] (where δ is the weighting coefficient) It can be defined as a function of the time-advancing value in at least one of the following cases.

[0586] In the embodiment,

[0587]

number

[0588] is, formula

[0589]

number

[0590] or

[0591]

number

[0592] (However, N TBS (where ε represents the maximum TBS size with no restrictions, and ε is the weighting coefficient) and / or

[0593]

number

[0594] or

[0595]

number

[0596] It can be defined as a function of the time-advancing value in at least one of the following cases.

[0597] The weighting coefficients γ, δ, and ε that can be used as shown above may have the following characteristics: The weighting coefficients are modified according to the class / category of the WTRU or UE, and / or the weighting coefficients may differ depending on the transmission mode. In addition, the maximum TBS

[0598]

number

[0599] is, T TAIt can also be defined as a function of a class / category of WTRU or UE. For example, for WTRU or UE category-1, the TBS limit cannot be used regardless of the time advance value.

[0600] In another example, H-ARQ timing may be implemented (e.g., to allow for additional decoding time). In H-ARQ operation, the WTRU or UE may be required to send a HARQ-ACK in subframe n+k if the WTRU or UE may have received a PDSCH in subframe n. In one such embodiment, k is set to 4 in an FDD system, and k may be predefined in a TDD system based on, for example, the UL-DL configuration and / or subframe number. In addition, in one such embodiment, the behavior of the WTRU or UE may be defined as follows (e.g., if the WTRU or UE may have received an ePDCCH and the corresponding PDSCH in subframe n): The WTRU or UE may send a HARQ-ACK in subframe n+l. In one such embodiment, the variable l may be set to k if a single component carrier may be activated. In addition, the variable l may be set to a positive integer greater than 4 if multiple component carriers may be activated. The variable l can also be configured via upper-layer signaling to a number within a set of candidates, e.g., {4, 6, 8, 10}, when multiple component carriers may be activated. When only a single component carrier may be activated, l can be set to k.

[0601] In an additional example, the ePDCCH and its corresponding PDSCH may be transmitted in different subframes so that the WTRU or UE expects to observe the ePDCCH in subframe ni and receive the corresponding PDSCH in subframe n. In this case, the WTRU or UE's actions in response to the HARQ-ACK transmission may include one or more of the following:

[0602] For example, the variable i can be either "0" or a positive integer and can be constructed by upper-layer signaling. In one embodiment, the variable i may be set to "1" in an FDD system. A WTRU or UE can send a HARQ-ACK in subframe nk regardless of the subframe number for ePDCCH reception. The ePDCCH may be restricted to transmission in subframe ni if ​​multiple component carriers may be activated. Otherwise, the ePDCCH and the corresponding PDSCH may be transmitted in the same subframe.

[0603] ePDCCH is a time advance (T) relative to WTRU or UE. TA ) can also be transmitted in subframe ni if ​​it is acceptable to assume that it is greater than the threshold (α). TA >In α, the WTRU or UE can expect to receive the corresponding PDSCH in subframe n if the WTRU or UE can receive the ePDCCH in subframe ni. TA For ≤α, the WTRU or UE can receive (or can expect to receive) the ePDCCH and the corresponding PDSCH in the same subframe (e.g., α = 0.17 ms).

[0604] In addition, the number of available downlink PRBs (e.g., associated with system bandwidth) in ePDCCH is N PRB If it can be considered larger, it can be transmitted as a subframe ni. PRB is a threshold, and in one example embodiment, N PRB =50 is acceptable. ePDCCH may be further transmitted as a subframe ni to Category 5 UEs.

[0605] One or more combinations of the embodiments disclosed above may also be implemented. For example, the ePDCCH may have multiple component carriers activated and time advance (T) relative to the WTRU or UE. TA) can be transmitted in subframe ni if ​​it is acceptable to consider it to be greater than the threshold. ePDCCH is a time advance (T) relative to WTRU or UE. TA ) may be transmitted in subframe ni if ​​it is greater than the threshold and the WTRU or UE category may be 5. ePDCCH is a time advance (T) relative to the WTRU or UE. TA ) is greater than the threshold, and the number of available downlink PRBs (e.g., system bandwidth) is N PRB If it can be considered larger, it may be transmitted as a subframe ni.

[0606] Implementations of TDD (e.g., frame structure 2) can also be realized and / or used as described herein. For example, in TDD, HARQ-ACK timing may be defined according to or based on the UL-DL configuration and / or subframe number, for example, once the WTRU or UE can receive the PDSCH in subframe n, the uplink subframe may not be available in n+4. Table 16 shows an embodiment as an example of a HARQ-ACK timing relationship by defining k so that the WTRU or UE transmits a HARQ-ACK in uplink subframe n+k after detecting the PDSCH in downlink subframe n.

[0607] [Table 22]

[0608] In one embodiment, the TBS limit can be applied to subframes having k, which may be less than or equal to a value K that is predefined or configurable by upper-layer signaling. For example, if K may be equal to 4, the TBS limit is applied to subframes 0 and 5 in UL-DL configuration 0 in Table 16, which may also be applied to subframe 4 in UL-DL configuration 1. In another example, if K may be equal to 5, the TBS limit may be applied to one or more of the following subframes: subframes {0, 5} in configuration 0, subframes {4, 9} in configuration 1, subframes {3, 8} in configuration 2, subframe {0} in configuration 3, subframes {8, 9} in configuration 4, subframes {7, 8} in configuration 5, and / or subframe {9} in configuration 6.

[0609] According to an additional embodiment, the TBS restriction is that the HARQ-ACK timing is greater than K, and T occurs in WTRU or UE. TAThis can be applied to subframes where >α is possible. Furthermore, from the perspective of the WTRU or UE's PDSCH decoding procedure, the WTRU or UE can assume that the maximum TBS limit may not apply if the HARQ-ACK timing k may be greater than K (e.g., 4) in the subframe. Different WTRU or UE behavior may be defined in such cases. For example, if the WTRU or UE can receive a TBS within a limited TBS in a subframe where the HARQ-ACK timing k may be less than or equal to K, the WTRU or UE can assume that such a reception is an error and that it may report a DTX or NACK in subframe n+k. If the WTRU or UE can receive a TBS within a limited TBS in a subframe where the HARQ-ACK timing k may be greater than K, the WTRU or UE can begin decoding the PDSCH and report a HARQ-ACK in subframe n+k. For TDD and FDD, the TBS limit may be applied in downlink subframes if the WTRU or UE can report a HARQ-ACK 4ms after receiving the PDSCH in that subframe.

[0610] Embodiments for mitigating feedback processing time (e.g., using FDD (e.g., frame structure 1) and TDD (e.g., frame structure 2)) are described herein. As described above, CSI feedback may be provided and / or used. If aperiodic CSI reporting may be triggered in downlink subframe n, the WTRU or UE may report the CSI in uplink subframe n+4. Since the calculation of the CSI may use further processing time, if aperiodic CSI reporting may be triggered by ePDCCH in downlink subframe n, the behavior of the WTRU or UE may include at least one of the following:

[0611] A WTRU or UE may drop CSI feedback if a PDSCH may be transmitted to the WTRU or UE in the same subframe. In this case, the conditions for dropping the feedback may be further restricted by at least one of the following: the TBS for the PDSCH in subframe n is greater than a predefined threshold; a subband CQI and / or rank is used in a non-periodic CSI feedback mode; or time advance T TA The conditions are that the value is greater than a predefined threshold, that the CSI-RS associated with the aperiodic CSI feedback is transmitted in the same subframe, and that the system bandwidth N PRB This includes the condition that it is greater than a predefined threshold (e.g., 50), and / or a similar condition.

[0612] In one embodiment, the WTRU or UE cannot assume that an aperiodic CSI report can be triggered in subframe n via ePDCCH if the PDSCH may be transmitted in the same subframe. Such conditions may be further restricted by at least one of the following: the TBS for the PDSCH in subframe n is greater than a predefined threshold; a subband CQI and / or rank is used in aperiodic CSI feedback mode; and time advance T TA The conditions are that the value is greater than a predefined threshold, that the CSI-RS associated with the aperiodic CSI feedback is transmitted in the same subframe, and that the system bandwidth N PRB This includes the condition that it is greater than a predefined threshold (e.g., 50), and / or a similar condition.

[0613] In addition, if the CSI request fields in DCI formats 0 and 4 can trigger a non-periodic CSI report in subframe n, the WTRU or UE can feed back the CSI in subframe n+4 in the FDD system. In one embodiment, the WTRU or UE can perform this operation if it can receive legacy PDCCH.

[0614] According to an example embodiment, if a WTRU or UE can receive an ePDCCH for aperiodic CSI reporting in a multi-carrier system, the operation of the WTRU or UE may include one or more of the following: The WTRU or UE can report CSI feedback in subframe n+j, where j is set to 4 if a single component carrier can be activated, j is set to 5 regardless of the number of configured component carriers (cells), j is configured by a higher layer, and j is used when multiple component carriers can be configured, j is set to 4 for PCell, j is set to 5 for SCell, the reporting times for PCell and SCell are defined according to the cell so that they can be separated in the time domain, and / or j is a time advance (T) for the WTRU or UE which may be greater than a threshold TA ), a periodic reporting that triggers a bit which can instruct the reporting of CSI for multiple component carriers, and / or can be configured according to at least one of the cases in which the configured PUSCH reporting mode can be based on subband precoding matrix indicator (PMI) reporting.

[0615] As such, time relaxation for WTRU or UE processing (e.g., WTRU or UE decoding) across multiple carriers can be implemented as described herein. In such embodiments, time relaxation for HARQ-ACK transmission and / or aperiodic CSI feedback may be redefined when the ePDCCH may be used, for example, in a multi-carrier system. In addition, PDSCH decoding processing can also be provided.

[0616] Uplink control channel allocation by ePDCCH can be further described herein. For example, PUCCH resource mapping to a single DL carrier can be performed. In one such embodiment, the PUCCH resource corresponding to the DL allocation message received by ePDCCH may be configured as a function of RRC signaling that can be directed to one or more WTRUs or UEs.

[0617] If ePDCCH reception can be enabled or configured for a WTRU or UE, at least one or a set of candidate PUCCH resources can be assigned or directed to the WTRU or UE. PUCCH resources can be directed or signaled to one or more WTRUs or UEs using per-WTRU specific signaling or per-UE specific signaling, or they can be directed or signaled to WTRUs or UEs in a cell-specific manner. After receiving a DL assignment message regarding ePDCCH in a DL subframe, the WTRU or UE can determine the corresponding PUCCH resource in the UL subframe as a function of acceptable or pre-configured PUCCH resources.

[0618] In another embodiment, an assigned ePDCCH resource may correspond to a predetermined or configured set of PUCCH resources. A WTRU or UE that receives an assignment of an ePDCCH resource for decoding DL control information can obtain the corresponding PUCCH resource, or a set of acceptable PUCCH resources as a function of a predetermined mapping relationship or table. For example, a WTRU or UE may transmit a PUCCH resource on a single assigned PUCCH resource, or if multiple PUCCH resources may be configured, assigned, or directed, it may transmit a PUCCH on a resource selected from the set, and the determination of a particular PUCCH resource may follow at least one second determination parameter, such as the signaled value portion of its DCI (e.g., ARI in the TPC field of Release 10), or one or more values ​​that can be derived as a function of a transmission setting such as a DL assignment message mapping to an ePDCCH resource (e.g., a value associated with the DMRS antenna port number for MU-MIMO). Explicit configuration of corresponding PUCCH resources for a small or appropriately sized number of WTRUs or UEs decrypting ePDCCHs can provide flexibility in pooling PUCCH resources while keeping them under network control and avoiding the introduction of protocol processing associated with legacy WTRUs decrypting PDCCHs.

[0619] In addition, the PUCCH resource corresponding to the DL allocation message received by the ePDCCH can be derived through a dynamic resource allocation mechanism technique as a function of one or more transmission settings of at least one DL signal received through the ePDCCH. The PDCCH's CCE index n CCEThe PUCCH resources that can be derived using this method can be extended by defining the number of CCEs for ePDCCH transmissions. In one such embodiment, PUCCH resource conflicts between legacy PDCCH and ePDCCH can be avoided by reusing similar PUCCH resource allocation principles, for example, when legacy WTRUs or UEs and ePDCCH WTRUs or UEs can be supported on the serving cell.

[0620] PUCCH resource allocation using a single ePDCCH resource set may also be provided and / or used. For example, a PUCCH resource for a single ePDCCH set may be defined as described herein. In one embodiment, if either the eCCE and / or eREG unit in the ePDCCH may be defined similarly to a legacy PDCCH, the corresponding PUCCH resource for antenna port p0 is

[0621]

number

[0622] Defined or derived as, the PUCCH resource for antenna port p1 is,

[0623]

number

[0624] This can be derived by, however, n CCE This is the number of the first CCE used for transmitting the corresponding PDCCH within the ePDCCH region (e.g., the lowest eCCE index),

[0625]

number

[0626] This is the total number of CCEs in the restricted area for legacy PDCCH,

[0627]

number

[0628] It can be composed of higher layers. In this case, one or more of the following are applicable:

[0629]

number

[0630] It is dynamically calculated based on PCFICH detection (e.g., detection of the number of OFDM symbols) and system bandwidth.

[0631]

number

[0632] This is set to a predefined offset value, for example, the maximum number of CCEs for the maximum system bandwidth.

[0633]

number

[0634] Combined with this,

[0635]

number

[0636] This can be composed of the upper layers.

[0637]

number

[0638] Resource allocation is

[0639]

number

[0640] and

[0641]

number

[0642] It can be configured by upper-layer signaling so that it can be based on the following. In this case, at least one of the following is applicable:

[0643]

number

[0644] This is often composed of upper layers and / or commonly used in PDCCH and ePDCCH (for example, in this case,

[0645]

number

[0646] (which may be composed of upper layers), as well as / or

[0647]

number

[0648] teeth,

[0649]

number

[0650] It can be constructed through upper-level signaling without requiring any further instructions.

[0651] In addition, in one embodiment, the PUCCH resource is

[0652]

number

[0653] and

[0654]

number

[0655] n eCCE It can be considered unrelated to this. For transmit modes that can support one or more (e.g., up to two) antenna ports, see the PUCCH resource.

[0656]

number

[0657] teeth,

[0658]

number

[0659] It can be given by. If the WTRU or UE can consist of MU-MIMO transmission, another decision parameter n MU However, for example, with respect to antenna port p0

[0660]

number

[0661] And for antenna port p1:

[0662]

number

[0663] Like n eCCE In addition, it can be used for the corresponding PUCCH resource. In such one embodiment, n MU This can be determined as at least one of the following: a parameter that can be associated with an antenna port for UE-specific DMRS, a parameter similar to ARI (ACK / NACK resource indicator) composed of higher-layer signaling, and / or a predetermined parameter.

[0664] In another example, the PUCCH resources corresponding to DL assignments that may be received by ePDCCH can be derived as a function of the number of CCEs. For example, the first or predetermined CCE or equivalent mapping unit in an ordered sequence can be obtained by decoding DL assignment messages that can be mapped in a time and / or frequency resource grid.

[0665] In addition, a sequence of mapping units such as eCCE or eREG that a WTRU or UE may choose to dynamically derive or determine a PUCCH resource selection when decoding an ePDCCH may or may not have a relationship with the CCE sequence and start CCE index that may be used in connection with dynamic PUCCH resource allocation when decoding a PDCCH. A WTRU or UE decoding an ePDCCH that determines a PUCCH resource may calculate both a UL transmit setting from a first dynamically calculated transmit setting, such as a start (e)CCE or equivalent and one or more pre-configured or signaled parameters, as described herein.

[0666] According to one embodiment as an example, PUCCH resources that may be used in relation to PDCCH (e.g., if present) and ePDCCH may be segmented or aggregated for WTRUs assigned by the network to decode one of them. During setup, UL RBs for PUCCH resources, e.g., for decoding PDCCH by legacy WTRUs or UEs and for decoding ePDCCH by WTRUs or UEs, may be pooled. In some additional embodiments (e.g., when seeking to obtain spatial multiplexing gain), isolated UL resources may be selected with respect to those that can decode legacy PDCCHs by WTRUs and ePDCCHs.

[0667] In the above example, when introducing (e)CCE and / or (e)REG units, it is impossible to imply or know that the group or unit of REs may be the same as a CCE containing a REG containing four REs used on nine REGs or PDCCHs. In addition, the ordered sequence of mapping units corresponding to time and / or frequency resource allocation for one or more ePDCCHs may be equivalent in the embodiments described. In one embodiment, a PUCCH resource that can be configured to accept multiple DL serving cells for decoding by a WTRU or UE of at least one ePDCCH may be derived through RRC signaling to one or more WTRUs or UEs.

[0668] Embodiments also describe PUCCH resource allocation using multiple ePDCCH resource sets. For example, if either the eCCE or eREG unit in the ePDCCH set can be defined similarly to a legacy PDCCH, the corresponding PUCCH resource for the UE is for antenna port p0.

[0669]

number

[0670] Derived as, and / or the PUCCH resource for antenna port p1,

[0671]

number

[0672] This can be derived by, however, n eCCE This is the number of the first eCCE that can be used to transmit the corresponding PDCCH within the region of the configured ePDCCH set for the UE (e.g., the lowest eCCE index that can be used to construct the PDCCH),

[0673]

number

[0674] is the PUCCH resource offset for the ePDCCH set, and / or

[0675]

number

[0676] It can be composed of higher layers. In this embodiment, one or more of the following are applicable:

[0677]

number

[0678] It is dynamically calculated based on PCFICH detection (e.g., detection of the number of OFDM symbols) and system bandwidth.

[0679]

number

[0680] This is set to a predefined offset value, for example, the maximum number of CCEs for the maximum system bandwidth, and / or

[0681]

number

[0682] Combined with this,

[0683]

number

[0684] This is composed of upper layers, and / or

[0685]

number

[0686] This is comprised of upper-layer signaling, and the resulting resource allocation is

[0687]

number

[0688] This may be based on the following. In this last embodiment, at least one of the following is applicable:

[0689]

number

[0690] It is often composed of a higher layer and / or used in PDCCH and ePDCCH (for example, in this case,

[0691]

number

[0692] (It can be composed of upper layers),

[0693]

number

[0694] teeth,

[0695]

number

[0696] Without specifying otherwise, it is constructed by upper-layer signaling, and / or

[0697]

number

[0698] Each set is independently constructed, and this

[0699]

number

[0700] It can be defined as follows.

[0701] multiple

[0702]

number

[0703] (wherein k=0, ..., K-1) can also be configured and / or directed via dynamic signaling. For example, PUCCH resource allocation based on ePDCCH is

[0704]

number

[0705] It can be defined as follows: In this case, one or more of the following are applicable: k can be dynamically indicated by the DCI associated with the PDSCH transmission in the subframe. For example, a bit field can indicate the value of k so that the UE derives a PUCCH resource. In addition, the ARI in the DCI can be reused to indicate k. A scrambler ID for the DCI (e.g., nSCID) can also implicitly indicate k. K may be the same as the number of ePDCCH resource sets that can be configured, and / or each k may have a one-to-one mapping to a configured ePDCCH resource set. K can also be defined as 2 or 4, and / or K=1 if a single ePDCCH resource set can be configured.

[0706] In alternative or additional embodiments,

[0707]

number

[0708] teeth,

[0709]

number

[0710] Combined with,

[0711]

number

[0712] It may be dynamically signaled and / or semi-statically, or configured by a higher layer. If the WTRU or UE may consist of MU-MIMO transmission, another (e.g., second) decision parameter n MU However, for antenna port p0

[0713]

number

[0714] And for antenna port p1:

[0715]

number

[0716] Like n eCCE In addition, it can be used for the corresponding PUCCH resource, however, n MU This can be determined as at least one of the following: parameters associated with the antenna port for UE-specific DMRS, parameters similar to ARI composed of higher-layer signaling, and / or predetermined parameters.

[0717] PUCCH resource mappings for multiple DL carriers may also be provided and / or used as described herein. For example, if ePDCCH reception is enabled or configured for a WTRU or UE and the WTRU or UE may be configured to accept multiple DL serving cells, a PUCCH resource corresponding to a first DL allocation message received on a first ePDCCH may be derived by the WTRU or UE as a function of a second DL allocation message received on a second DL control channel.

[0718] In addition, in one embodiment, the WTRU or UE can decode a legacy PDCCH on the primary (DL) serving cell while simultaneously decoding an ePDCCH on the secondary (DL) serving cell. The PUCCH resource used may be determined by the WTRU or UE as a function of the DL assignment message received on the primary serving cell. For two DL serving cells, a derived PUCCH format 1 with a channel selection resource may be obtained from the DL assignment message on the primary cell. For PUCCH format 3, the WTRU or UE can select a PUCCH resource from a set of parameters signaled by a pre-configured RRC through the use of an ARI transmitted in the DL assignment message of the (e)PDCCH of the secondary serving cell.

[0719] The WTRU or UE can also decode ePDCCHs in both the primary and secondary serving cells. In one such embodiment, the PUCCH resources used are determined by the WTRU or UE as a function of the first ePDCCH and may be used to transmit UL control information such as A / Ns corresponding to one or more received DL assignments of these ePDCCHs. For two DL serving cells, the derived PUCCH format 1 with channel selection resources may be obtained from the DL assignment message on the primary cell.

[0720] Embodiments also describe PUCCH resource allocation using a single ePDCCH resource set. For example, if the eCCE and / or eREG units in ePDCCH can be defined similarly to those in legacy PDCCH, the corresponding PUCCH resources are:

[0721]

number

[0722] For transmit modes defined or derived as and supporting up to two transport blocks, see the PUCCH resource.

[0723]

number

[0724] teeth,

[0725]

number

[0726] Defined or derived by, however, n eCCE This is the number of the first CCE used to transmit the corresponding PDCCH within the ePDCCH region (for example, the lowest eCCE index used to construct the PDCCH),

[0727]

number

[0728] This is the total number of CCEs in the restricted area for legacy PDCCH,

[0729]

number

[0730] It can be composed of upper layers.

[0731]

number

[0732] This can be dynamically calculated based on PCFICH detection (e.g., detection of the number of OFDM symbols) and system bandwidth.

[0733]

number

[0734] This is set to a predefined offset value, for example, the maximum number of CCEs for the maximum system bandwidth.

[0735]

number

[0736] Combined with this,

[0737]

number

[0738] It can be composed of upper layers.

[0739] In one embodiment, the PUCCH resource is

[0740]

number

[0741] and

[0742]

number

[0743] n eCCE It can be considered unrelated to this. For transmit modes that support up to two transport blocks, see the PUCCH resource.

[0744]

number

[0745] teeth,

[0746]

number

[0747] It can be given by.

[0748] In addition, if the WTRU or UE can be configured for MU-MIMO transmission, the corresponding PUCCH resource is:

[0749]

number

[0750] Derived as follows, for transmit modes that support multiple (e.g., up to 2) transport blocks, see PUCCH resources

[0751]

number

[0752] teeth,

[0753]

number

[0754] Derived by, where n MU This can be determined as at least one of the following parameters: a parameter that can be associated with an antenna port for a UE-specific DMRS; a parameter similar to ARI composed of upper-layer signaling; a parameter that may be similar to ARI transmitted in the TPC field of the DL assignment message of the secondary serving cell's (e)PDCCH (e.g., Rel-10); and / or a predetermined parameter.

[0755] In PUCCH resource allocation using multiple ePDCCH resource sets, the PUCCH resources for multiple ePDCCH sets can be defined as follows: If either the eCCE or eREG unit in the ePDCCH set can be defined similarly to a legacy PDCCH, the corresponding PUCCH resource for the UE is:

[0756]

number

[0757] Derived as follows, for transmit modes that support up to two transport blocks, see PUCCH resources

[0758]

number

[0759] teeth,

[0760]

number

[0761] Derived by, where n eCCE This is the number of the first CCE used to transmit the corresponding PDCCH within the region of the configured ePDCCH set to the UE (e.g., the lowest eCCE index used to construct the PDCCH),

[0762]

number

[0763] This is the PUCCH resource offset for the ePDCCH set,

[0764]

number

[0765] It can be composed of upper layers.

[0766]

number

[0767] It can be signaled dynamically or configured semi-statically.

[0768]

number

[0769] teeth,

[0770]

number

[0771] In other words

[0772]

number

[0773] It can be combined with,

[0774]

number

[0775] It can be dynamically signaled or semi-statically configured by a higher layer. If the WTRU or UE can be configured for MU-MIMO transmission, the corresponding PUCCH resource is

[0776]

number

[0777] Derived as follows, for transmit modes that support up to two transport blocks, see PUCCH resources

[0778]

number

[0779] teeth,

[0780]

number

[0781] Derived by, however, nMU may be determined as at least one of the following: parameters associated with the antenna port to the UE-specific DMRS, parameters similar to ARI composed of upper-layer signaling, parameters similar to ARI transmitted in the TPC field of the DL assignment message of the secondary serving cell's (e)PDCCH (e.g., Rel-10), and / or predetermined parameters.

[0782] In the case of PUCCH format 3, the WTRU or UE can select a PUCCH resource from a set of parameters signaled by a pre-configured RRC through the use of a signaled resource selector, for example, the ARI transmitted in the DL allocation message of (e)PDCCH via a secondary serving cell.

[0783] Based on the foregoing, in the case of a single carrier for the use of explicitly configured or implicitly derived PUCCH resources, or a combination of both, PUCCH format 3 can be used for carrier aggregation with multiple DL serving cells, for example, a primary DL serving cell and at least one secondary cell.

[0784] PDSCH transmit modes associated with ePDCCH may be further provided and / or used as described herein. For example, for PDSCH transmission, several transmit modes may be available within the system to support various channel / system environments, such as closed-loop spatial multiplexing mode, open-loop spatial multiplexing mode, transmit diversity, and / or single antenna port mode. Transmit modes may be configured via higher-layer signaling, for example, so that the eNB scheduler can select the appropriate transmit mode for PDSCH transmission. Table 3 shows the transmit modes supported by LTE / LTE-A. ePDCCH may be used in transmit modes that use antenna ports 7-10 for PDSCH demodulation. If a specific transmit mode can be configured, such as transmit mode 2, where the WTRU or UE can use CRS for PDSCH demodulation, the WTRU or UE can monitor legacy PDCCH for PDSCH reception. If a WTRU or UE can be configured to monitor an ePDCCH while the configured transmit mode for a PDSCH is 2 (e.g., transmit diversity mode), the WTRU or UE can monitor a legacy PDCCH that receives DCIs associated with the PDSCH in subframes. If a WTRU or UE can be configured to monitor an ePDCCH while the configured transmit mode for a PDSCH is 9, the WTRU or UE can monitor an ePDCCH that receives DCIs in a WTRU or UE-specific search space in subframes configured to receive ePDCCHs.

[0785] In addition, ePDCCH can be used regardless of the transmission mode configured for PDSCH transmission. For example, the transmission mode or CQI reporting mode configured for a WTRU or UE may be implicitly associated with the type of ePDCCH transmission. The supported ePDCCH transmission types may differ depending on the configured transmission mode. For example, if a WTRU or UE can be configured with an open-loop transmission mode such as transmit diversity (e.g., TM mode-2) or open-loop space multiplexing mode (e.g., TM mode-3), the WTRU or UE may assume that the ePDCCH resource set configured for the WTRU or UE can be used as a distributed transmission. An open-loop transmission mode for a PDSCH may be associated with ePDCCH distributed transmission. A closed-loop transmission mode for a PDSCH may be associated with ePDCCH centralized transmission. The supported ePDCCH transmission types may differ depending on the configured CQI reporting mode. For example, if a WTRU or UE can be configured in reporting mode using PMI and CQI reporting, the WTRU or UE can assume that the ePDCCH resource set configured for the WTRU or UE can be used for centralized transmission. If a WTRU or UE can be configured in broadband CQI reporting in PUSCH reporting mode, the WTRU or UE can assume that the ePDCCH resource set configured for the WTRU or UE is for distributed transmission. Otherwise, the WTRU or UE can assume that the ePDCCH resource set configured for the WTRU or UE is for centralized transmission or both. If a WTRU or UE can be configured for CoMP transmission mode, the WTRU or UE can also assume that the ePDCCH resource set configured for the WTRU or UE can be defined as centralized transmission.

[0786] Systems and / or methods for receiving ePDCCH may be provided herein. For example, a WTRU or UE may be configured with an ePDCCH or legacy PDCCH, and the operation of the WTRU or UE to receive an ePDCCH may be as follows: The WTRU or UE may receive ePDCCH configuration information in broadcast information. For example, an MIB or SIB may include an ePDCCH configuration so that the WTRU or UE knows the ePDCCH resource before the RACH procedure. To receive broadcast information such as an SIB, the WTRU or UE may decode SI-RNTI on a legacy PDCCH. The WTRU or UE may be configured to receive legacy PDCCH and / or ePDCCH in the RACH procedure. In a competition-based RACH procedure, the WTRU or UE may receive PDCCH configuration information in either msg2 or msg4, which may be transmitted from the eNB. In a non-contradiction-based RACH procedure, the WTRU or UE can receive PDCCH configuration information in handover / mobility information or msg2, which may be transmitted from the eNB. If the WTRU or UE can be configured to a specific PDCCH type, the WTRU or UE can blind-decode DCIs in the configured PDCCH region (e.g., legacy PDCCH or ePDCCH). If the WTRU or UE can be configured to a specific PDCCH type, the WTRU or UE can blind-decode the common search space in the legacy PDCCH region and the WTRU or UE-specific search space in the ePDCCH region.

[0787] In some embodiments, systems and / or methods for PDCCH fallback transmission may also be disclosed. For example, an ePDCCH may be defined additionally on top of a legacy PDCCH, and an eNB may configure the legacy PDCCH or ePDCCH in a WTRU or UE-specific manner to utilize PDCCH resources. If PDCCH resources may be configured by higher-layer signaling, there may be a period of ambiguity during which the eNB does not know whether the WTRU or UE is monitoring the legacy PDCCH or ePDCCH. To enable the WTRU or UE to receive PDCCH regardless of PDCCH configuration, at least one of the following may be used:

[0788] The eNB can transmit both legacy PDCCH and ePDCCH in the same subframe during ambiguity periods, allowing the WTRU or UE to detect any PDCCH resources being monitored from the HARQ-ACK DTX. PDCCH resources for legacy PDCCH and ePDCCH can be defined independently.

[0789] The common search space is defined in the legacy PDCCH, and a fallback transmission mode (e.g., DCI format 1A) may be used during the ambiguity period. The PDCCH resource configuration can indicate the legacy PDCCH or ePDCCH with respect to the WTRU or UE-specific search space. For example, in one embodiment, the fallback PDCCH resource may be defined in the broadcast channel. The common search space is defined in the legacy PDCCH or ePDCCH via the broadcast channel (e.g., SIB-x), and the common search space cannot be modified according to the PDCCH configuration.

[0790] In addition, a PDCCH type can consist of a legacy PDCCH or an ePDCCH with an activation timer. If a WTRU or UE monitors a legacy PDCCH, it can use a triggered PDCCH based on the legacy PDCCH, and the triggered PDCCH can notify the WTRU or UE to monitor the ePDCCH from subframe n+x when a predefined or configurable triggered PDCCH may be received in subframe n. If a WTRU or UE monitors an ePDCCH, it can use a triggered ePDCCH based on the ePDCCH, and the triggered ePDCCH can notify the WTRU or UE to monitor the legacy PDCCH from subframe n+x when a predefined or configurable triggered ePDCCH may be received in subframe n.

[0791] A MAC CE using activation and / or deactivation commands may be used to configure a PDCCH type in one embodiment. For example, an activation and / or deactivation command may be transmitted using a timer such as x, so that when a WTRU or UE receives the MAC CE in subframe n, the command may be activated and / or deactivated in subframe n+x with x being a predefined or configured value.

[0792] In an example embodiment, if multiple component carriers can be configured, at least one of the following may be used to handle periods of ambiguity. For example, a common search space may be defined in the legacy PDCCH of PCell, and cross-carrier scheduling may be activated. In addition, cross-carrier scheduling may be activated for the common search space and available within the legacy PDCCH region. A WTRU or UE-specific search space may also be defined in the legacy PDCCH and / or ePDCCH (e.g., with or without cross-carrier scheduling).

[0793] Embodiments for handling or avoiding collisions with other signals may also be described herein. The ePDCCH RB may be the same as the RB on which the ePDCCH candidate is located. Although described in the case of collisions between ePDCCH and PRS, the embodiments described may apply in other cases, for example, when an ePDCCH resource may collide with other signals, including other reference signals, or broadcasting channels. Although described for handling or avoiding collisions with other signals, the embodiments described may apply in other cases, for example, to restrict or otherwise impose some form of limitation on ePDCCH to or from certain resource elements (REs), RBs, or subframes for any reason.

[0794] In one embodiment, the reception of PRS information by a WTRU or UE may be implemented and / or used. For example, a WTRU or UE may receive PRS information for a cell for reasons other than positioning, such as a cell from which it can read or which can be configured for an ePDCCH. A WTRU or UE may receive this information from an eNB, for example, via RRC signaling, which may be dedicated or broadcast signaling. A WTRU or UE may receive this information along with an ePDCCH configuration, which may be received via dedicated or broadcast signaling. A particular cell from which a WTRU or UE can receive and / or from which this information may be the WTRU or UE's serving cell, for example, a primary serving cell (PCell) or a secondary serving cell (SCEll). A WTRU or UE may also receive this information for an adjacent cell as part of mobility information or as part of a configuration related to handover to another serving cell.

[0795] In one exemplary embodiment, information that can be received for a given cell with a WTRU or UE may include one or more of the following: subframes that can be used to transmit PRS, PRS configuration index, number of DL subframes, BW for PRS transmission, PRS muting information, PRS period, PRS offset, PRS muting period, PRS muting sequence (e.g., PRS opportunities may be muted during each PRS muting period), and / or instructions on whether the cell transmits PRS. For a PRS muting sequence that may be included as part of the PRS muting information, if a p-bit field can be used to represent a muting sequence for a period p, the first bit of the field may correspond to the first PRS positioning opportunity that may begin after the start of SFN=0 for the cell, which may be received by the WTRU or UE.

[0796] eNB scheduling may be used or performed in one embodiment. For example, an eNB may schedule and / or transmit an ePDCCH in a manner that avoids or reduces the impact of collisions between an ePDCCH RB and a PRS RB. In a subframe in which an eNB can transmit a PRS in a given cell, the eNB may choose not to schedule or transmit an ePDCCH on any RB in that cell. In a subframe in which an eNB can transmit a PRS in a given cell, the eNB may choose not to schedule or transmit an ePDCCH on RBs that overlap with the PRS BW in that cell, for example, on RBs that could collide with the PRS RB in that cell. An eNB may configure an ePDCCH in a given cell such that it does not collide with a PRS in a subframe in which the eNB can transmit a PRS in that cell. This may be applicable, for example, to cases where the PRS BW cannot be the full DL BW of the cell.

[0797] Whether an eNB schedules or transmits an ePDCCH in some subframes or some RBs may depend on whether, or to what extent, the ePDCCH DM-RS RE conflicts with the PRS RE. For example, if in a given subframe in which an eNB can transmit a PRS, one or more ePDCCH RBs may conflict with the PRS RB, then one or more of the following may apply: An eNB may transmit an ePDCCH in a subframe or on a collision RB if an ePDCCH DM-RS RE cannot collide with a PRS RE in the collision RB; an eNB may not transmit an ePDCCH in a subframe or on a collision RB if at least one ePDCCH DM-RS RE can collide with a PRS RE in the collision RB; an eNB may not transmit an ePDCCH in a subframe or on a collision RB if a particular ePDCCH DM-RS RE collides with a PRS RE in the collision RB; an eNB may not transmit an ePDCCH in a subframe or on a collision RB if at least a certain number of ePDCCH DM-RS REs collide with a PRS RE in the collision RB; an eNB may not transmit an ePDCCH in a subframe or on a collision RB if a collision between an ePDCCH RE and a PRSS RE in the collision RB renders some or at least a certain number of antenna ports unusable in those RBs, and this is due to a collision between one or more ePDCCH REs and PRS REs; and / or similar.

[0798] For example, embodiments relating to a WTRU or UE receiving an ePDCCH for collision handling may be described herein. The WTRU may decide whether to monitor or attempt to decode ePDCCH candidates in several subframes or RBs of a cell based on at least one or more PRS parameters or transmission characteristics for that cell. The WTRU or UE may consider subframes from which PRS may be transmitted. For example, in subframes from which PRS may be transmitted, the WTRU or UE may not (or may be permitted not to) monitor or attempt to decode PDCCH candidates in those subframes, or may not (or may be permitted not to) monitor or attempt to decode ePDCCH candidates in those subframes.

[0799] In one embodiment, the WTRU or UE may consider subframes and RBs in which ePDCCH and / or PRS may be transmitted. For example, in subframes in which PRS may be transmitted, the WTRU or UE may not (or may be permitted not to) monitor or attempt to decode the ePDCCH candidate(s) in those subframes if the ePDCCH candidate(s) may be located in an RB in which they may collide with a PRS RB. In subframes in which PRS may be transmitted, the WTRU or UE may not (or may be permitted not to) perform one or more of the following: Examples include monitoring or attempting to decode ePDCCH candidates in subframes where at least one of the ePDCCH candidates may be located in an RB that could collide with the PRS RB; monitoring or attempting to decode ePDCCH candidates in subframes where more than a certain number of ePDCCH candidates may be located in an RB that could collide with the PRS RB; monitoring or attempting to decode ePDCCH candidates in subframes where ePDCCH candidates in those subframes (e.g., each or all of them) may be located in an RB that could collide with the PRS RB; monitoring or attempting to decode ePDCCH candidates located in an RB that could collide with the PRS RB; and / or similar actions. In a subframe in which a PRS may be transmitted, the WTRU may (or may need to) monitor or attempt to decode one or more ePDCCH candidates located in RBs that cannot collide with the PRS RB in that cell and / or several (e.g., each or all) ePDCCH candidates, if there are no ePDCCH candidates that can be located in RBs that can collide with the PRS RB (e.g., if there can be no overlap between the RB in which an ePDCCH candidate(s) can be located and the PRS RB).

[0800] In addition, the WTRU or UE may consider the subframes and REs that the PRS may transmit, and may also consider, for example, whether or to what extent the PRS RE may collide with the ePDCCH DM-RS RE. In a subframe in which a PRS may be transmitted, the WTRU or UE may (or may be required) monitor or attempt to decode ePDCCH candidates located in an RB that can collide with a PRS RB if none of the ePDCCH DM-RS REs in the collision RB can collide with a PRS RE, and / or may not (or may be permitted not to) monitor or attempt to decode ePDCCH candidates located in an RB that can collide with a PRS RB if at least one ePDCCH DM-RS RE in the collision RB can collide with a PRS RE, and / or may not (or may be permitted not to) monitor or attempt to decode ePDCCH candidates located in an RB that can collide with a PRS RB if several ePDCCH DM-RS REs in the collision RB can collide with a PRS RE, and / or may not (or may be permitted not to) monitor or attempt to decode ePDCCH candidates located in an RB that can collide with a PRS RB if at least a certain number of ePDCCH DM-RS REs in the collision RB can collide with a PRS RE. It may be impossible (or may be permitted not to) attempt to monitor or decode ePDCCH candidates located in RBs that may collide with RBs, and / or it may be impossible (or may be permitted not to) attempt to monitor or decode ePDCCH candidates located in RBs that may collide with PRS RBs if some, or at least a number of, antenna ports in colliding RBs may become unusable in those RBs due to collisions between one or more ePDCCH REs and PRS REs, and / or similar.

[0801] In a subframe that can be transmitted in a cell given a PRS, the WTRU or UE is the physical layer cell ID,

[0802]

number

[0803] Defined as, however

[0804]

number

[0805] PRS v can be assumed to be the physical layer cell identifier. shift Based on the value of the value, or at least one of the cyclic prefixes (CP lengths) of a subframe or cell that may be normal or extended, it is possible to determine which ePDCCH candidates it can (or may need to) monitor or attempt to decode, or which it cannot (or may be allowed not to). One or more of these parameters may be used by the WTRU to determine the location of a PRS RE, which the WTRU or UE may use to determine which ePDCCH DM-RS REs may conflict with the PRS RE.

[0806] In a cell given a PRS, in a subframe that may be transmitted, the WTRU or UE may determine which ePDCCH candidates it can (or should) attempt to monitor or decode, or cannot (or may be permitted not to monitor or decode), based on at least the number of antenna ports configured for that ePDCCH within that cell. If an antenna port may be restricted in some subframes, the WTRU may use the restricted port instead of the configured port in those subframes for its decision. For example, antenna ports {7, 8, 9, 10} may normally be used in a subframe, but antenna ports {7, 8} or {9, 10} may be used in some subframes.

[0807] In another embodiment, a fallback of the search space may be implemented or used. For example, for a WTRU configured for an ePDCCH, the PDCCH may include a common search space. In some subframes, such as subframes in which a PRS may be transmitted, the PDCCH may include a WTRU or UE-specific search space for a WTRU or UE configured for an ePDCCH. In a subframe, if a WTRU or UE configured for an ePDCCH cannot (or may be permitted not to) attempt to monitor or decode an ePDCCH candidate, for example, according to one of the resolution methods described herein, the WTRU or UE may (or may need to) attempt to monitor or decode the common search space and / or the WTRU or UE-specific search space in the PDCCH region.

[0808] For example, a WTRU or UE configured for an ePDCCH may feel back to monitor or attempt to decode PDCCH candidates that may be defined within a WTRU or UE-specific search space in the PDCCH region. Fallback may occur or be used in a subframe where a PRS is transmitted in a cell and / or based on at least one of the following: PRS information (e.g., one or more of the information items described herein), PRS transmission parameters, physical layer cell ID, CP length in the cell or subframe (e.g., normal or extended), the number of antenna ports configured for ePDCCH transmission, antenna port limitations, and / or similar.

[0809] Some subframes may be configured as fallback subframes. The eNB can provide such configurations to the WTRU or UE. According to an example embodiment, such configurations may be received by the WTRU or UE from the eNB via broadcast or dedicated signaling, such as RRC signaling.

[0810] In subframes that can be configured as fallback subframes, a WTRU or UE configured for an ePDCCH cannot (or may not) attempt to monitor or decode ePDCCH candidates. For a particular WTRU or UE, such as a WTRU or UE configured for an ePDCCH in a subframe that can be configured as a fallback subframe, a WTRU or UE-specific search space for that WTRU or UE may be defined within the PDCCH region. In these subframes, a WTRU or UE can (or may be required) monitor or attempt to decode PDCCH candidates, such as PDCCH candidates in the common search space and / or PDCCH candidates in the WTRU or UE-specific search space, within the PDCCH region. In subframes that cannot be configured as fallback subframes, a particular WTRU or UE, such as a WTRU or UE configured for an ePDCCH, can (or may be required) monitor or attempt to decode ePDCCH candidates in the PDSCH region. A fallback subframe may consist of at least one of the following parameters: duration, offset, number of consecutively configured subframes (e.g., number of consecutive DL subframes), and / or other parameters.

[0811] In addition, the configuration of an ePDCCH subframe or ePDCCH monitoring subframe is equivalent to the configuration of a fallback subframe, and an ePDCCH subframe or ePDCCH monitoring subframe can be handled in the opposite manner to that of a fallback subframe. For example, a WTRU or UE and / or eNB can handle a subframe that cannot be configured as an ePDCCH subframe or ePDCCH monitoring subframe in the same manner as described herein for a subframe that can be configured as a fallback subframe. A WTRU or UE and / or eNB can handle a subframe that can be configured as an ePDCCH subframe or ePDCCH monitoring subframe in the same manner as described herein for a subframe that cannot be configured as a fallback subframe.

[0812] Embodiments for processing PRS REs may be described herein. For ePDCCH candidates that may be located in RBs that a WTRU or UE can attempt to decode in a subframe in which a PRS may be transmitted, the WTRU or UE may assume that the ePDCCH is not transmitted in an RE that could collide with the PRS RE, for REs that may contain data (e.g., REs that do not contain CRS, DM-RS, or CSI-RS). For ePDCCH REs, the WTRU or UE may assume that rate matching is performed appropriately in these REs and / or puncturing is performed in these REs.

[0813] A WTRU or UE may have and / or acquire knowledge of PRS parameters and / or transmission characteristics from the information provided thereto, and such information may be used for collision handling. For example, a WTRU or UE may acquire knowledge from an E-SMLC (e.g., via LPP signaling) or from an eNB (e.g., via RRC signaling). These parameters may include one or more of the parameters described herein, as well as other parameters.

[0814] Based on these and / or other parameters, the WTRU or UE can determine in which subframes and / or in which RBs within those subframes a PRS may be transmitted within a given cell. The WTRU or UE may or may not consider PRS muting when determining in which subframes of a cell a PRS may be transmitted.

[0815] When determining whether a DM-RS RE, for example, an ePDCCH DM-RS RE, may collide with a PRS RE in the RB of a given cell, the WTRU or UE considers the CP length for the subframe or cell, the number of antenna ports configured for the ePDCCH transmission, the cell's physical cell ID, and the PRS v which can be derived from the cell's physical cell ID. shift Values, for example,

[0816]

number

[0817] You may use one or more of these.

[0818] In addition, for example, location or antenna port mapping may be used for DM-RS REs for collision handling, according to one embodiment as an example. The eNB can change the placement of DM-RS in an RB where an ePDCCH candidate may be located within a subframe of a cell from which a PRS may be transmitted. In a subframe in a given cell from which the eNB can transmit a PRS, the eNB can change the placement of DM-RS REs, such as an ePDCCH DM-RS RE, to avoid collisions with PRS REs. The eNB can change the placement of DM-RS REs, such as an ePDCCH DM-RS RE, if otherwise at least one DM-RS RE may collide with a PRS RE. The eNB can change the placement of DM-RS REs, such as an ePDCCH DM-RS RE, which may collide with a PRS RE if otherwise not changed.

[0819] Some DM-RS REs whose placement can be moved may include one or more (e.g., all) DM-RS REs that would otherwise collide with a PRS RE, one or more (e.g., all) DM-RS REs having the same carrier frequency as a DM-RS RE that would otherwise collide with a PRS RE, and / or one or more (e.g., all) DM-RS REs at adjacent carrier frequencies to a DM-RS RE that would otherwise collide with a PRS RE (e.g., all) (for example, if a DM-RS RE at frequency X collides with a PRS RE, then DM-RS REs at adjacent frequencies to X may be moved).

[0820] In subframes where PRS may be transmitted, the eNB's interpretation of antenna ports for DM-RS, such as ePDCCH DM-RS, may be modified. This interpretation involves the cell's physical cell ID and the cell's PRS V. shift This may be a function of at least one or more of the following: CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission.

[0821] The placement change may be frequency-related, such as increasing or decreasing the frequency. The placement change may or may not include a change in the symbol. The placement change affects the cell's physical cell ID and the cell's PRS v shift This may be a function of at least one or more of the following: CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission.

[0822] In a cell where an eNB can transmit a PRS, the eNB may change the placement of DM-RS REs, such as ePDCCH DM-RS RE, in some subframes to avoid or reduce collisions with PRS REs in subframes where the eNB can transmit a PRS. These some subframes may include subframes where the eNB can transmit a PRS and / or not transmit a PRS; for example, some subframes may include all subframes. The eNB may change the placement as described above. In this cell (for example, a cell where the eNB can transmit a PRS), the eNB's interpretation of antenna ports with respect to DM-RS, such as ePDCCH DM-RS, may be modified in some subframes to align with desired modifications in subframes where the eNB can transmit a PRS. These some subframes may include subframes where the eNB can transmit a PRS and / or not transmit a PRS; for example, some subframes may include all subframes.

[0823] In a cell where the eNB may or may not transmit a PRS, the eNB may modify the placement of DM-RS REs, such as ePDCCH DM-RS RE, in a subframe based on where the PRS might be located if the cell were to transmit a PRS. The eNB may modify the placement as described herein. In this cell (for example, a cell where the eNB may or may not transmit a PRS), the eNB's interpretation of antenna ports with respect to DM-RS, such as ePDCCH DM-RS, may be modified in a subframe to align with what would be the desired modification if the cell were to transmit a PRS.

[0824] The eNB may move the DM-RS RE or modify the interpretation of the antenna port in one or more of the ways described for the ePDCCH DM-RS RE in a given subframe. For example, the eNB may move the DM-RS RE or modify the interpretation of the antenna port for a PDSCH permitted by the ePDCCH in that subframe in the same or similar way.

[0825] In subframes where a PRS may be transmitted, the WTRU or UE may attempt to monitor or decode ePDCCH candidates using a modified DM-RS pattern (which may differ from, for example, the DM-RS pattern used for ePDCCH in subframes where a PRS is not transmitted). In these subframes (e.g., subframes where a PRS may be transmitted), the WTRU or UE's interpretation of antenna ports with respect to DM-RS such as ePDCCH DM-RS may be modified. This interpretation includes the cell's physical cell ID and the cell's PRS v shift This may be a function of at least one or more of the following: CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission.

[0826] In one or more subframes of a cell capable of transmitting a PRS (e.g., including all subframes), the WTRU or UE may monitor or attempt to decode ePDCCH candidates using a modified DM-RS pattern (e.g., which may differ from the DM-RS pattern used for ePDCCH in cells that cannot transmit a PRS). In these subframes (e.g., one or more subframes of a cell capable of transmitting a PRS, including all subframes), the WTRU or UE's interpretation of antenna ports for DM-RS such as ePDCCH DM-RS may be modified. This interpretation includes the cell's physical cell ID and the cell's PRS v shift This may be a function of at least one or more of the number of antenna ports configured for ePDCCH transmission, and / or for ePDCCH transmission.

[0827] The interpretation of the modified DM-RS pattern and / or antenna port is based on the location of the PRS RB, the location of the PRS RE, the physical layer cell ID of the cell, and the PRS v of the cell. shift This may be a function of at least one or more of the following: CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission.

[0828] According to one embodiment, a WTRU or UE can use a modified DM-RS pattern or antenna port interpretation to decode a PDSCH, such as a PDSCH permitted by an ePDCCH, which can use a modified DM-RS pattern or antenna port interpretation. For example, a WTRU can use a modified DM-RS pattern, such as the same or similar pattern used for ePDCCH DM-RS, to decode a PDSCH permitted by an ePDCCH in a subframe where the ePDCCH uses a modified DM-RS pattern. In another example, a WTRU can use a modified antenna port interpretation, such as the same or similar interpretation used for ePDCCH DM-RS, for a PDSCH permitted by an ePDCCH in a subframe where the ePDCCH uses a modified antenna port interpretation.

[0829] In addition, embodiments for restricting antenna ports to DM-RS REs can be described, for example, to handle collisions. For example, an eNB can impose antenna port restrictions in an RB where a candidate ePDCCH may be located within a subframe of a cell from which a PRS may be transmitted. In a subframe in a given cell from which an eNB can transmit a PRS, the eNB can restrict the use of certain antenna ports for the ePDCCH and / or PDSCH. Such restrictions may depend on the cell's physical layer cell ID and the cell's PRS v shift This may be based on at least one of the following: CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission. For example, if antenna ports 7, 8, 9, and 10 can be configured for ePDCCH transmission, the restriction limiting it to ports 7 and 8 or ports 9 and 10 is imposed in the subframe from which the PRS can be transmitted, and this restriction is based on the cell's physical layer cell ID, PRS v shiftIt may be based on at least one of the following: and / or CP length (e.g., for a cell, subframe, or regular subframe).

[0830] In a subframe in which a PRS may be transmitted, the WTRU or UE may attempt to monitor or decode an ePDCCH candidate using a restricted set of antenna ports. The WTRU or UE may use a restricted set of antenna ports, such as the same or similar set used for ePDCCH DM-RS, for PDSCHs authorized by the ePDCCH in a subframe in which the ePDCCH uses a restricted set of antenna ports. Where a restricted set of antenna ports may be used, that restricted set may replace, for example, a configured or other set of antenna ports in any of the solutions or embodiments described herein.

[0831] Different ePDCCH configurations may be implemented for several subframes, such as PRS subframes (e.g., for collision handling). In one such embodiment, with respect to a cell, there may be a configuration for an ePDCCH for use in subframes where a PRS may be transmitted, different from the ePDCCH for use in subframes where a PRS may not be transmitted. In subframes where a PRS may be transmitted, the WTRU or UE may monitor or attempt to decode ePDCCH candidates according to the configuration for those subframes. The WTRU or UE may receive ePDCCH configurations for subframes where a PRS may be transmitted from the eNB via dedicated or broadcast signaling, which may be RRC signaling, for example. The WTRU or UE may receive one or more ePDCCH configurations and receive instructions from the eNB, for example, on which configuration to use and when. For example, instructions may indicate which subframe (e.g., a subframe where a PRS may or may not be transmitted) or under what circumstances to use a particular configuration.

[0832] In a subframe where a PRS may be transmitted, the PRS may also be overridden (for example, for collision handling). For example, an RE such as ePDCCH RE may override a PRS RE. Overriding a first signal over a second signal may prevent the transmission of the second signal, while enabling the transmission of the first signal. For example, RE1 may override RE2, so that RE1, or the signal in RE1, is transmitted, while RE2, or the signal in RE2, is not transmitted.

[0833] In a subframe in which a PRS may be transmitted, an RE can override the PRS RE (for example, in the event of a collision with a PRS RE). For example, such an override may occur if one or more of the following are true: the RE is an ePDCCH DM-RS RE such as an ePDCCH DM-RS RE; the RE is a specific ePDCCH DM-RS RE, such as an ePDCCH DM-RS RE corresponding to a specific antenna; the RE is an ePDCCH DM-RS RE in the ePDCCH common search space (for example, any ePDCCH DM-RS RE); the RE is an RE in the ePDCCH common search space such as any RE in the ePDCCH common search space; and / or similar situations.

[0834] For example, if an RE such as ePDCCH RE or ePDCCH DM-RS RE can override a PRS RE, a collision between the RE and the PRS RE can be eliminated or avoided (for example, the PRS RE or the signal within the PRS RE cannot be transmitted). If a collision between an RE and a PRS RE can be eliminated or avoided, for example, by override, the WTRU can determine that a collision between the RE and the PRS RE is impossible. Based on this determination, the WTRU can make various decisions, such as whether to monitor or attempt to decode ePDCCH candidates that may be placed in an RB or RE in a subframe where a PRS may be transmitted in the cell.

[0835] Blind decoding (e.g., its optimization) may be performed (e.g., for collision handling). For example, based on the configured ePDCCH resources, a WTRU or UE may perform numerous blind decodings, which may be referred to as a complete set of blind decodings. In one example, if some of the ePDCCH candidates may be located in RBs that may collide with PRS RBs in subframes where PRSs may be transmitted in a cell, the WTRU or UE may monitor or attempt to decode a subset of configured RBs where the ePDCCH candidates may be located. In such a scenario, the WTRU or UE may perform one or more of the following: use a complete set of blind decodings in a subset of RBs (e.g., to recover the entire decoding for a subframe), and / or use a set of blind decodings in a subset of RBs that may be more than a set for these RBs as part of the complete configuration, but less than or equal to the complete set of the complete configuration. For example, if a complete set of RBs corresponds to N blind decryptions, and a subset corresponds to M of these Ns, then when attempting to decrypt the subset (or only the subset), the WTRU or UE can use W blind decryptions, where W is N or M ≤ W ≤ N.

[0836] In addition, in embodiments (e.g., for collision handling), the eNB may have or acquire knowledge regarding the positioning capabilities of a WTRU or UE and / or which WTRU or UE may have knowledge of PRS transmissions and / or PRS parameters. For example, the eNB may receive information from the E-SMLC or another network entity regarding the positioning capabilities of a WTRU or UE and / or which WTRU or UE may have knowledge of PRS transmissions and / or PRS parameters in one or more cells. The eNB may request and / or receive this and / or other information, for example, via an LPPa interface or protocol. For a given or specific WTRU or UE (or WTRU or UE), this information may include whether the WTRU or UE is capable of supporting ODOA, whether PRS information has been provided to the WTRU or UE (e.g., by an E-SMLC or other network entity, e.g., as part of positioning assistance data), whether PRS information may have been provided to a particular cell or a group of cells (e.g., a cell under the control of an eNB, which may be one or more serving cells of the WTRU or UE), for which one or more cells such information may have been provided to the WTRU or UE, and / or whether the PRS information may have been successfully received by the WTRU or UE, and / or one or more of the same. PRS information may include one or more of the PRS transmit subframes, BW, RB, RE, muting information, and / or any other information relating to PRS (e.g., parameters used to determine the PRS information or enumerated information described herein).

[0837] An E-SMLC and / or another network entity may know whether the PRS information has been successfully received by the WTRU or UE based on the fact that it has received an acknowledgment (ACK) or other instruction from the WTRU or UE in response to the successful receipt of this information, which may have been provided by the E-SMLC or other network entity. If there is no ACK or other instruction from the WTRU or UE in response to the E-SMLC or other network entity providing the PRS information, the E-SMLC or other network entity's knowledge that the WTRU or UE is aware of the PRS information may not be reliable.

[0838] A WTRU or UE may also process PRS information from one or more sources (for example, for collision handling). For example, a WTRU or UE may receive PRS information for a cell from at least one source, such as an E-SMLC, an eNB controlling cell transmission of PRS, another cell, or another network entity. The WTRU or UE may process the PRS information it receives as described herein.

[0839] Knowledge of a cell's PRS transmission information by a WTRU or UE may be outdated or unreliable, for example, if that information may have been received from an E-SMLC or a network entity other than the eNB that may control or possess knowledge of the PRS information. For example, while an eNB can notify an E-SMLC or other network entity of a change in PRS transmission parameters for one or more cells, the PRS information known to the WTRU or UE may be inaccurate if the WTRU or UE receives the PRS information about the cell and PRS information changes, for example, some time later. This information may remain inaccurate until the eNB notifies the E-SMLC or other network entity of the change, and / or the E-SMLC or other network entity notifies the WTRU or UE.

[0840] A WTRU or UE may use (or only be able to use) PRS information it can receive from an eNB to determine, for example, how to process ePDCCHs within a cell or in a cell's PRS subframe that can transmit PRS. The eNB may be the eNB responsible for PRS transmission in a cell, or another eNB that can provide the WTRU or UE with configuration for that cell (for example, as part of the information provided in the signaling related to handover). A WTRU or UE may not (or may not be allowed to) use (or be permitted to use) PRS information it can receive from another source, such as an E-SMLC or another network entity, to determine, for example, how to process ePDCCHs within a cell or in a cell's PRS subframe that can transmit PRS. This may be provided (or may be beneficial) when the eNB is unaware of which WTRU or UE may have obtained PRS information from another source, such as an E-SMLC or another network entity. The behavior of a WTRU or UE may be unknown to the eNB or unpredictable to the eNB if the WTRU or UE were to use information received from another source. eNB may transmit PRS information to the WTRU or UE that differs from information that may be transmitted to the WTRU or UE by E-SMLC or other network entities in order to perform specific actions.

[0841] A WTRU or UE may use PRS information it can receive from an E-SMLC or other network entity to determine how to process an ePDCCH within a cell or in a cell's PRS subframe, for example, to send a PRS. If a WTRU or UE can receive PRS information for a given cell from multiple sources, the WTRU or UE may expect the information from multiple sources to be the same, and the behavior may be undefined if they are not the same. A WTRU or UE may, considering PRS information for a given cell received from an eNB, override any PRS information it may have already received from a source (e.g., any source) for the purpose of processing an ePDCCH. A WTRU or UE may, considering PRS information for a given cell received from any source, override any PRS information it may have already received from a source (e.g., any source) for the purpose of processing an ePDCCH.

[0842] Furthermore, embodiments for handling collisions between ePHICH and PRS may be described (for example, to handle collisions). In a subframe in which a PRS may be transmitted, one or more of the following may apply: if an ePHICH may collide with a PRS, the ePHICH may override the PRS; if a DM-RS RE for an ePHICH may collide with a PRS RE, the DM-RS RE for an ePHICH may override the PRS RE; and / or if an ePHICH RE may collide with a PRS RE, rate matching may be performed on the ePHICH RE around the PRS RE. A WTRU or UE may take this into consideration when monitoring or attempting to decode an ePHICH.

[0843] One or more embodiments described herein for processing ePDCCH or ePDCCH and PRS may be applied to processing ePHICH or ePHICI and PRS. For example, a WTRU configured for at least one of ePDCCH or ePHICH may fall back to attempting to monitor or decode PHICH, and / or may not attempt to monitor or decode ePHICH in subframes where ePDCCH or ePDCCH monitoring or ePHICH or ePHICH monitoring may not be configured, in subframes where PRS may be transmitted, or in subframes where a collision or possibility of collision with PRS in these subframes would be guaranteed by one or more embodiments described herein.

[0844] A pseudo-matching antenna port may also be implemented and / or used in one embodiment. For example, demodulation of some downlink channels, such as PDSCH in some transmission modes, may require the WTRU or UE to estimate the channel from a reference signal, such as a WTRU or UE-specific reference signal (e.g., transmitted over antenna ports 7 through 14). As part of such a procedure, the WTRU or UE may perform fine-grained time and / or frequency synchronization processing on these reference signals, as well as estimation of certain characteristics related to the large-scale characteristics of the propagation channel.

[0845] In one embodiment, such a procedure can typically be facilitated by the assumption that another reference signal that can be measured periodically, such as a cell-specific reference signal, can share the same timing (e.g., and some other characteristics) as the WTRU or UE-specific reference signal. Such an assumption may be valid if these signals can be physically transmitted from the same set of antennas. On the other hand, in embodiments with geographically dispersed antennas, this assumption may not be valid because the WTRU or UE-specific reference signal (e.g., and associated downlink channel) may be transmitted from different locations than the cell-specific reference signal. As such, the WTRU or UE may be notified via a reference signal (e.g., CSI-RS) that can share the same timing and / or other characteristics as the reference signal used for demodulation. The corresponding antenna ports (e.g., two antenna ports) can then be "pseudo-matched" so that the large-scale characteristics of the signal received by the WTRU or UE from the signal received from the other antenna port. The "large-scale characteristics" may include one or more of the following: spread delay, spread Doppler, frequency shift, average received power, received timing, and so on. As described herein, ePDCCH can be demodulated using these reference signals which may be transmitted on antenna ports such as antenna ports 7-10. To take advantage of the potential capabilities of ePDCCH, and even the benefits of area division, ePDCCH can also be transmitted from the cell's transmission point. To transmit ePDCCH from the cell's transmission point, the user equipment UE may need to use and / or know one or more reference signals, such as CSI-RS, which can be pseudo-matched with the antenna port used to demodulate the ePDCCH. Unfortunately, using and knowing such reference symbols which can be pseudo-matched with the antenna port used to demodulate the ePDCCH can be difficult because potentially signaled downlink control information tends to become available after the ePDCCH has been decoded.

[0846] As such, systems and / or methods for issuing demodulation reference timing instructions may be disclosed herein. For example, a single demodulation reference timing may be given and / or used. In such embodiments (e.g., the first embodiment), the WTRU or UE may assume, identify, or determine that at least one pseudo-matching antenna port may be a predefined antenna port (e.g., at least one of ports 0-3 from which a cell-specific reference signal may be transmitted) and / or at least one antenna port configured by the upper layer (e.g., at least one of ports 15-23 of one configuration of the CSI-RS reference signal). The network may transmit the ePDCCH over the same transmission point corresponding to the predefined or pre-configured pseudo-matching antenna port to the WTRU or UE. The network may also transmit the ePDCCH over different transmission points if it knows that they are similar enough that the large-scale characteristics of the reference signal transmitted from this point do not affect the demodulation performance. For example, in one embodiment, if antenna port 0 (CRS) can be defined as a pseudo-matching antenna port, and CRS can be transmitted from nodes (including high-power and low-power nodes), the network may transmit ePDCCH from a particular low-power node if it knows that the timing of receiving a reference signal transmitted from that low-power node may be close enough to the timing of CRS.

[0847] To enable such an embodiment, the WTRU or UE can estimate at least one characteristic of at least one reference signal, such as CSI-RS, that may be known by the network to be transmitted from the obtained transmission point. The characteristics that can be measured may include at least one of the following: received timing, average received power, frequency shift, Doppler spread, delayed spread, and similar.

[0848] At least one of the above characteristics may relate to the same characteristic of another predefined or configured reference signal. For example, a WTRU or UE can estimate the difference in reception timing between the reference signal in question and a cell-specific reference signal (CRS). In another example, a WTRU or UE can estimate the ratio (in dB) of the average received power of the reference signal and the CRS.

[0849] In one embodiment, to calculate this estimate, the WTRU or UE may average across multiple antenna ports from which the reference signal may be transmitted. The WTRU or UE may also average across multiple subframes and multiple resource blocks (e.g., within the frequency domain). A new measurement type may also be defined for each of the characteristics described above.

[0850] A WTRU or UE may report measurement results for at least one characteristic to the network using RRC messages (e.g., measurement reports) or lower-layer signaling (e.g., MAC control elements or physical layer signaling). Using these results, the network can determine whether transmission from a particular point is feasible based on, or considering, an antenna port (or reference signal) that the WTRU or UE assumes, identifies, or determines will be pseudo-matched with the antenna port used for demodulation. For example, if the timing difference with the CRS that the WTRU or UE assumes, identifies, or determines will be pseudo-matched is too large, the network may transmit using the same transmission point used for the CRS (at the cost of loss or divided gain).

[0851] In addition, in one embodiment, the WTRU or UE may periodically trigger the transmission of measurement results. Alternatively, the WTRU or UE may trigger the transmission of results if at least one of the following events occurs: The WTRU or UE may trigger transmission when the difference in characteristics between reference signals exceeds or falls below a threshold. For example, the WTRU or UE may trigger the transmission of a report if the difference in reception timing between a particular configured CSI-RS and CRS exceeds a threshold. The WTRU or UE may also trigger transmission when the absolute value of the characteristics between reference signals exceeds or falls below a threshold. For example, the WTRU or UE may trigger the transmission of a report if the measured delay spread exceeds a threshold. Such events and associated parameters or thresholds may be configured as part of the measurement reporting configuration (e.g., reportConfig).

[0852] In a network, it is also possible to estimate whether several large-scale characteristics are similar (for example, if reception timings may be similar) by measuring uplink transmissions from WTRUs or UEs such as SRS, PUCCH, PUSCH, or PRACH, and similar, at different receiving points that occupy the same space as the transmitting point potentially used for downlink transmission.

[0853] Multiple demodulation reference timings may be given and / or used. In such embodiments (e.g., the second embodiment), at least one of the reference signals, such as CSI-RS, CRS, PRS, and similar signals, may be used to indicate the demodulation reference timing for the WTRU or UE in order to receive the ePDCCH and / or PDSCH based on a WTRU or UE-specific reference signal (e.g., antenna ports 7-14).

[0854] If a WTRU or UE is given or can be notified of a demodulation reference timing with respect to a reference signal, the WTRU or UE demodulation process, including FFT timing and channel estimation filter coefficients, may follow the reference signal. For example, if there are two CSI-RSs configured for a WTRU or UE, such as CSI-RS1 and CSI-RS2, and the WTRU or UE can report CSIs for both CSI-RS configurations, the FFT timing and fine-grained time and / or frequency synchronization for PDSCH demodulation may follow one of the two CSI-RS configurations according to the demodulation reference timing instructions.

[0855] Alternatively, if the WTRU or UE is notified of information regarding the demodulation reference timing with respect to the reference signal, the PDSCH demodulation procedure may differ depending on the type of reference signal based on one or more of the following:

[0856] If CSI can be used as the reference timing, the FFT timing and channel estimation filter coefficients for CSI-RS can be used for PDSCH demodulation. For example, a WTRU or UE can assume, identify, or determine that the PDSCH and / or WTRU or UE-specific demodulated RS (e.g., antenna ports 7-14) may be transmitted from the same pseudo-matched antenna ports. If a WTRU or UE can be configured to monitor an ePDCCH as such (e.g., for each PRB set), the WTRU or UE can identify a first set of antenna ports (e.g., 15-22) that are associated with or correspond to CSI-RS information and / or have a mapping to the PDSCH, and can assume, identify, or determine that other antenna ports (e.g., 7-14 or other ports) may be pseudo-collocated with respect to parameters such as Doppler shift, Doppler spread, mean delay, delay spread, and similar, as described above.

[0857] If the CRS can be used as the reference timing, the FFT timing and channel estimation filter coefficients relative to the CRS can be used for PDSCH demodulation. Alternatively, time and / or frequency offsets relative to the CRS may be given for PDSCH demodulation. If the WTRU or UE can be notified with respect to the offset, the WTRU or UE can apply the offset from the CRS. In exemplary embodiments, at least one of the FFT timing offset (ΔFFT), time offset (ΔT), frequency offset (ΔF), and similar may be given.

[0858] If PRS can be used as the reference timing, then the operation of WTRU or UE similar to either CSI-RS or CRS may be applied in such one embodiment.

[0859] In one embodiment, the demodulation criterion timing may be implicitly or explicitly communicated to the WTRU or UE. Furthermore, a single demodulation criterion may be applied to a given time window (e.g., a subframe or wireless frame), or multiple demodulation criteria may be used.

[0860] An implicit demodulation criterion timing instruction may be given and / or used. In such embodiments (e.g., the first solution), the demodulation criterion timing may be tied to the ePDCCH and / or PDCCH resource and implicitly communicated to the WTRU or UE. Since the DCI is received to demodulate the PDSCH, the demodulation timing criterion can be inferred from the location of the ePDCCH and / or PDCCH resource from which the WTRU or UE can receive the DCI. At least one of the following methods may be used to implement ePDCCH and / or PDCCH resource-based instructions.

[0861] In one embodiment, the WTRU or UE-specific search space is divided into two or more subsets, each subset of which may be associated with a specific demodulation timing criterion. For example, within the WTRU or UE-specific search space, the total number of blind decoding attempts may be 2N. blind It is divided into two subsets (subset1 and subset2), and each subset is an exclusive N blind This may include several blind decoding attempts, with each subset being associated with a different demodulation timing criterion. For example, subset 1 may be associated with CSI-RS1, and subset 2 may be associated with CSI-RS2. In one embodiment, if a WTRU or UE can receive a DCI for a PDSCH in subset 1, the WTRU or UE can assume, identify, or determine that the PDSCH may be transmitted at the same transmission point as CSI-RS1.

[0862] In addition, as described herein, within the search space specific to the ePDCCH WTRU or UE, a subset of the search space can be associated with a demodulation timing criterion. Thus, if the WTRU or UE can perform blind decoding on the ePDCCH, the WTRU or UE can assume, identify, or determine that subset1 and subset2 may be transmitted from the same transmission point as CSI-RS1 and CSI-RS2, respectively. In another embodiment, as described herein, if the WTRU or UE can receive DCI via the ePDCCH, the WTRU or UE can assume, identify, or determine that the corresponding PDSCH may be transmitted from the same transmission point as the ePDCCH. Furthermore, for a common ePDCCH search space (e.g., as described herein), the WTRU or UE can assume, identify, or determine that the ePDCCH may be transmitted from the same transmission point as the CRS.

[0863] In such an embodiment, if a WTRU or UE may be configured to monitor ePDCCH (e.g., for each PRB set), the WTRU or UE can determine mapping information and / or antenna port pseudo-collocation (e.g., ePDCCH) using a set of parameters indicated by higher-layer parameters such as CSI-RS.

[0864] According to another embodiment (e.g., the second solution), the demodulated antenna port may be associated with a demodulation timing criterion. If antenna ports 7-10 are available for ePDCCH and / or ...

Claims

1. A method implemented in a wireless transmitter / receiver unit (WTRU), A step of receiving one or more radio resource control transmissions that include information associated with physical downlink control channel communication, wherein the information is (i) Information indicating the time resources and frequency resources for each of one or more sets of resources, and (ii) a step including information indicating an association between a set of search spaces from one or more sets of search spaces and a set of resources from one or more sets of resources, A step of receiving one or more transmissions in the time resource and frequency resource of the resource set that include one or more physical downlink control channel candidates of the search space set, based on information indicating an association between the search space set and the resource set, wherein the search space set includes a plurality of corresponding aggregation levels and a corresponding number of physical downlink control channel candidates for each of the plurality of corresponding aggregation levels. Includes, A method wherein the time resources and frequency resources of the set of resources include a plurality of extended resource element groups.

2. The method according to claim 1, wherein the time resource and frequency resource of the set of resources include one or more extended control channel elements, each of the one or more extended control channel elements includes a plurality of the plurality of extended resource element groups, and each of the plurality of the plurality of extended resource element groups includes one or more resource element groups.

3. The method according to claim 1, wherein the plurality of extension resource element groups include consecutive extension resource element groups within the time resource and frequency resource of the set of resources, and the consecutive extension resource element groups are mapped to one or more extension control channel elements for centralized physical downlink control channel transmission.

4. The method according to claim 1, wherein the plurality of augmented resource element groups include augmented resource element groups interleaved within the time resource and frequency resource of the set of resources, and the interleaved augmented resource element groups are mapped to one or more augmented control channel elements for distributed physical downlink control channel transmission.

5. The method according to claim 1, wherein the plurality of extended resource element groups exclude the time resource used for the demodulation reference signal from the set of resources.

6. The method according to claim 1, wherein the set of one or more search spaces includes at least one of a set of user-specific search spaces and a set of common search spaces.

7. The method according to claim 1, wherein the time resources and frequency resources of the set of resources define a subset of available bandwidths in the frequency domain.

8. The method according to claim 1, wherein each of the one or more sets of resources includes information indicating an index for the corresponding set of resources, and the information indicating an association between the set of search spaces and the set of resources includes the index for the set of resources.

9. The method according to claim 1, wherein one or more of the plurality of extended resource element groups include a fixed number of resource elements.

10. The method according to claim 1, wherein one or more of the plurality of extended resource element groups include a variable number of resource elements.

11. A wireless transmit / receive unit (WTRU) comprising a circuit including a receiver, a transmitter, and a processor, One or more radio resource control transmissions are received that include information associated with physical downlink control channel communication, and the information is (i) Information indicating the time resources and frequency resources for each of one or more sets of resources, and (ii) Information indicating the association between a set of search spaces from one or more sets of search spaces and a set of resources from one or more sets of resources, Based on information indicating an association between the set of search spaces and the set of resources, one or more transmissions are received in the time resource and frequency resource of the set of resources, which include one or more physical downlink control channel candidates of the set of search spaces, the set of search spaces includes a plurality of corresponding aggregation levels, and a corresponding number of physical downlink control channel candidates for each of the plurality of corresponding aggregation levels. It is configured in such a way, The time resources and frequency resources of the set of resources include a WTRU comprising a plurality of extended resource element groups.

12. The WTRU according to claim 11, wherein the time resource and frequency resource of the set of resources include one or more extended control channel elements, each of the one or more extended control channel elements includes a plurality of the plurality of extended resource element groups, and each of the plurality of the plurality of extended resource element groups includes one or more resource element groups.

13. The WTRU according to claim 11, wherein the plurality of extension resource element groups include consecutive extension resource element groups within the time resource and frequency resource of the set of resources, and the consecutive extension resource element groups are mapped to one or more extension control channel elements for centralized physical downlink control channel transmission.

14. The WTRU according to claim 11, wherein the plurality of augmented resource element groups include augmented resource element groups interleaved within the time resource and frequency resource of the set of resources, and the interleaved augmented resource element groups are mapped to one or more augmented control channel elements for distributed physical downlink control channel transmission.

15. The WTRU according to claim 11, wherein the plurality of extended resource element groups exclude the time resource used for the demodulation reference signal from the set of resources.

16. The WTRU according to claim 11, wherein the set of one or more search spaces includes at least one of a set of user-specific search spaces and a set of common search spaces.

17. The WTRU according to claim 11, wherein the time resources and frequency resources of the set of resources define a subset of available bandwidth in the frequency domain.

18. The WTRU according to claim 11, wherein each of the one or more sets of resources includes information indicating an index for the corresponding set of resources, and the information indicating an association between the set of search spaces and the set of resources includes the index for the set of resources.

19. The WTRU according to claim 11, wherein one or more of the plurality of extended resource element groups include a fixed number of resource elements.

20. The WTRU according to claim 11, wherein one or more of the plurality of extended resource element groups include a variable number of resource elements.

21. A method implemented at a network node, A step of transmitting one or more radio resource control transmissions that include information associated with physical downlink control channel communication, wherein the information is (i) Information indicating the time resources and frequency resources for each of one or more sets of resources, and (ii) a step including information indicating an association between a set of search spaces from one or more sets of search spaces and a set of resources from one or more sets of resources, A step of transmitting one or more transmissions in the time resource and frequency resource of the resource set that include one or more physical downlink control channel candidates of the search space set, based on information indicating an association between the search space set and the resource set, wherein the search space set includes a corresponding number of aggregation levels and a corresponding number of physical downlink control channel candidates. Includes, A method wherein the time resources and frequency resources of the set of resources include a plurality of extended resource element groups.

22. A network node comprising a circuit including a receiver, a transmitter, and a processor, Send one or more radio resource control transmissions that include information associated with physical downlink control channel communication, and the information is (i) Information indicating the time resources and frequency resources for each of one or more sets of resources, and (ii) Information indicating the association between a set of search spaces from one or more sets of search spaces and a set of resources from one or more sets of resources, Based on information indicating an association between the set of search spaces and the set of resources, transmit one or more transmissions in the time resource and frequency resource of the set of resources that include one or more physical downlink control channel candidates of the set of search spaces, wherein the set of search spaces includes a corresponding number of aggregation levels and a corresponding number of physical downlink control channel candidates. It is configured in such a way, The time resources and frequency resources of the set of resources include a network node comprising multiple extended resource element groups.

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