System and / or method for providing epdcch in multiple carrier based and / or quasi-collated 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 TO RELATED APPLICATIONS This application is incorporated herein by reference in its entirety. This application claims the benefit of U.S. Provisional Patent Application No. 61 / 678,612, filed August 1, 2012, U.S. Provisional Patent Application No. 61 / 706,119, filed September 26, 2012, U.S. Provisional Patent Application No. 61 / 720,646, filed October 31, 2012, and U.S. Provisional Patent Application No. 61 / 753,279, filed January 16, 2013. [Background technology]

[0002] Current communication systems (e.g., LTE / LTE-Advanced systems) may be equipped with multiple antennas, multiple component carriers, and / or quasi-collated antenna ports to support transmissions. Such multiple antennas, multiple component carriers, and / or quasi-collated antenna ports may be equipped for various purposes, including increasing peak system throughput, expanding cell coverage, supporting higher Doppler, and the like. Unfortunately, such communication systems configure ePDCCH designs that may be ill-suited to support quasi-collated antenna ports, focus primarily on a single component carrier (e.g., rather than multiple component carriers and / or multiple antennas), have limited performance for multi-carrier systems, and / or are not properly designed to avoid errors within frames and / or subframes (e.g., special subframes), have severe PDSCH and / or CSI reporting processing times, are unable to make appropriate PUCCH resource allocations, or are unable to provide PDCCH indications during configuration and / or reference symbol periods where quasi-collating with antenna ports may occur, and are not provided with sufficient 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 Summary of the Invention [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 configuration, the UE or WTRU may be configured to monitor ePDCCH resources in a particular subframe. The WTRU may then monitor the ePDCCH resources in the subframe. In an example embodiment, the subframe may not be a special subframe, the configuration may be received via higher layer signaling, and the configuration may include one or more PRB sets to monitor on the ePDCCH resources, where the PRB sets may include sets of eCCEs that include eREGs, and further monitor PDCCH resources in different subframes, demodulate the 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 may derive an aggregation level (e.g., eCCE aggregation level) for a subframe. The UE or WTRU may determine the aggregation level number N for that subframe. AL Such an aggregation level can be derived based on AL may be a positive integer. The UE or WTRU may AL For example, if the search space is {1, 2, 4, 8} and N AL If is 2, the UE or WTRU may monitor according to {2, 4, 8, 16}.

[0006] Systems, methods, and means for receiving or monitoring an ePDCCH or PDSCH may also be 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. The UE or WTRU may perform demodulation of the PDSCH or ePDCCH using demodulation timing based on the type. For example, if the reference signal is a channel state 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, the 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 drawings]

[0007] The details of the invention can be better understood from the following description, taken, for example, in conjunction with the accompanying drawings. [Figure 1A] 1 is a diagram of an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram of an example wireless transmit / receive unit (WTRU) that may be used within the communication system illustrated in FIG. 1A. [Figure 1C] 1B is a system diagram of an example radio access network and an example core network that may be used within the communication system illustrated in FIG. 1A. [Figure 1D] 1B is a system diagram of another example radio access network and an example core network that may be used within the communication system illustrated in FIG. 1A. [Figure 1E] 1B is a system diagram of another example radio access network and an example core network that may be used within the communication system illustrated in FIG. 1A. [Figure 2]FIG. 1 illustrates an example embodiment of a WTRU or UE specific precoded DM-RS. [Figure 3] FIG. 1 illustrates an exemplary embodiment of a non-precoded cell-specific RS. [Figure 4] FIG. 10 illustrates an example embodiment of a WTRU or UE-specific DM-RS for a normal CP (eg, port 5). [Figure 5] FIG. 1 illustrates an example embodiment of a CRS structure based on the number of antenna ports. [Figure 6] FIG. 10 illustrates an example embodiment of a DM-RS pattern that can support, for example, eight layers. [Figure 7] FIG. 10 illustrates an example embodiment of CSI-RS patterns that can be reused based on the number of ports. [Figure 8] FIG. 1 illustrates an example embodiment of a positioning architecture. [Figure 9] FIG. 1 illustrates an example embodiment of REG definition within a downlink control channel region with 2Tx CRS. [Figure 10] FIG. 1 illustrates an example embodiment of REG definition within a downlink control channel region with 4Tx CRS. [Figure 11] FIG. 1 illustrates an example embodiment of PCI-based PCFICH REG allocation. [Figure 12] FIG. 1 illustrates an example embodiment of PCI-based PCFICH and PHICH REG allocation. [Figure 13] FIG. 1 illustrates an exemplary embodiment of ePDCCH multiplexing (e.g., FDM multiplexing) with PDSCH. [Figure 14] FIG. 1 illustrates an exemplary embodiment of a mapping of PUCCH to physical resource blocks. [Figure 15] FIG. 1 illustrates an exemplary embodiment of a collision between a DM-RS and a PRS. [Figure 16]FIG. 1 illustrates an exemplary embodiment of ePDCCH resource allocation within a subframe. [Figure 17] FIG. 1 is a diagram of an exemplary embodiment of carrier aggregation with different TDD UL-DL configurations. [Figure 18] FIG. 1 illustrates an example embodiment of CCE aggregation across multiple carriers in a distributed resource allocation. [Figure 19] FIG. 10 illustrates an example embodiment of PRB pairs that may be used for ePDCCH transmission based on the number of antenna ports (eg, ports 7-10 and 7-8, respectively). [Figure 20] FIG. 1 illustrates an exemplary embodiment of eCCE-eREG mapping in ePDCCH based on centralized and / or distributed allocation. [Figure 21] FIG. 1 illustrates an exemplary embodiment of eCCE-eREG mapping with contiguous allocation. [Figure 22] FIG. 2 illustrates an example embodiment of a block interleaver. [Figure 23] FIG. 1 illustrates an exemplary embodiment of hybrid allocation by using a block interleaver. [Figure 24] FIG. 1 illustrates an exemplary embodiment of coexistence of centralized and / or distributed eCCE. [Figure 25] FIG. 1 illustrates an example embodiment of antenna port mapping for eREG and eCCE. [Figure 26] FIG. 1 illustrates an exemplary embodiment of a common search space definition in a legacy PDCCH region within a PCell. DETAILED DESCRIPTION OF THE INVENTION

[0008] A detailed description of exemplary embodiments will now be provided with reference to the figures. However, while the embodiments herein may be described in connection with the exemplary embodiments, they should not be limited thereto, and other embodiments may be used, or modifications and additions may be made to the described embodiments to perform the same or similar functions of the disclosure without departing from the invention. Additionally, the figures may illustrate call flows that may be exemplary. It will be understood that other embodiments may also be used. The order of the flows may be changed. Also, flows may be omitted if not implemented, and additional flows may be added if available.

[0009] Systems and / or methods may be disclosed that provide efficient downlink control channel design (e.g., an enhanced downlink control channel) in multicarrier-based wireless networks (e.g., networks such as those described in FIGS. 1A-1E). For example, such systems and / or methods may provide and / or utilize centralized and / or distributed resource allocation in multicarrier systems, including, for example, providing distributed resource allocation for multiple component carriers. In addition, PDSCH and / or CSI feedback processing time mitigation, including flexible PDSCH processing time adaptation based on multi-component carrier reception in combination with ePDCCH and / or flexible CSI reporting time adaptation based on reporting bandwidth, number of component carriers, and the like, may be provided and / or used in such systems and / or methods. In one embodiment, such a system and / or method may further provide for and / or use an ePDCCH and / or legacy uplink control signaling relationship, including cross-carrier scheduling and / or new allocation of ePDCCH physical and / or logical addresses (e.g., CCE indices) to uplink control channel relationships. TDD-specific embodiments for such a system and / or method may also be provided for and / or used, including use of the ePDCCH in special subframes and / or TDD interband. According to one example embodiment, a PDCCH fallback transmission mode may be provided for and / or used for such a system and / or method when UE or WTRU operation of PDCCH reception is within an ambiguity period and uses an RRC-configured PDCCH configuration between the legacy PDCCH and the ePDCCH.

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

[0011] According to one embodiment, such a system and / or method provides and / or uses antenna port mapping rules based on a common search space and a WTRU- or UE-specific search space in distributed transmission and / or antenna port association with a WTRU- or UE-specific configuration, including a combination of RE position-based mapping and / or WTRU- or UE-specific configuration. 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 for such a system and / or method. In addition, adaptive eREG-to-eCCE mapping, mapping rules based on subframe characteristics, and the like may be provided and / or used. In an additional embodiment, TBS restrictions in TDD mode due to 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 with variable resource sizes per set determined by a downlink control information (DCI) format determined by ePDCCH candidates, ePDCCH resource sets determined by a hash function, and / or system bandwidth with an ePCFICH indication of the number of ePDCCH resource sets.

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

[0014] In one embodiment, such a system and / or method may also provide a PRS collision handling technique that includes broadcasting PRS configuration information and / or effecting WTRU or UE behavior when ePDCCH resources may collide with a PRS.

[0015] Multiple ePDCCH resource sets for a multi-carrier system may be further provided and / or defined by such systems and / or methods. For example, a DM-RS sequence 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. Additionally, 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 with multiple ePDCCH resource sets may be provided and / or used, and / or search space definition for centralized transmissions may be provided and / or used, including ePDCCH transmission-specific hash function definition and / or ePDCCH transmission-specific eCCE indexing, such as indexing different eCCEs by or based on aggregation levels. An eREG-to-eCCE mapping may also be provided and / or used. For example, cell-specific eREG-to-eCCE mapping based on centralized and distributed transmission may be provided and / or used. In one embodiment, supported transmission modes associated with the ePDCCH may also be provided and / or defined, including, for example, a subset of the transmission modes supported by the ePDCCH and / or supportable ePDCCH types (e.g., centralized and distributed), which may differ (e.g., according to the transmission scheme).

[0016] Additionally, such systems and / or methods may provide WTRU- or UE-specific search spaces (e.g., equations associated therewith) and hash functions for ePDCCH. For example, search space equations and / or hash functions for centralized and distributed ePDCCH with multiple ePDCCH sets may be provided and / or used.

[0017] Such a system and / or method may further provide an ePDCCH common search space including eREG / eCCE definitions for the common search space, starting symbols (e.g., associated therewith), 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 providing demodulation reference timing indications may be disclosed. For example, single demodulation reference timing support and multiple demodulation reference timing support, such as resource-specific demodulation reference timing, and indications of demodulation reference timing (e.g., demodulation reference timing indications) may be provided as described herein.

[0019] 1A is a diagram of an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through 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), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like.

[0020] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, and / or 102d (which may be referred to generally or collectively as WTRUs 102), 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, although it is understood that disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, pagers, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, consumer electronics devices, and the like.

[0021] The communications system 100 may also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the core networks 106 / 107 / 109, the Internet 110, and / or the network 112. For example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNodeB, a home Node B, a home eNodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b may each be depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

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

[0023] The base station 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 115 / 116 / 117, which may be any suitable wireless communications link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 115 / 116 / 117 may be implemented using any suitable radio access technology (RAT).

[0024] More specifically, as noted above, the communication system 100 may be a multiple-access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a and the WTRUs 102a, 102b, and 102c in the RANs 103 / 104 / 105 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may comprise communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may comprise High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0025] In another embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 115 / 116 / 117 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A).

[0026] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology 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 the like.

[0027] The base station 114b in FIG. 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize a suitable RAT to facilitate wireless connectivity within a localized area, such as a business, a home, a car, a campus, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114b does not need to access the Internet 110 via the core network 106 / 107 / 109.

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

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

[0030] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may have multi-mode capabilities, i.e., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based wireless technology, and with the base station 114b, which may employ an IEEE 802.11 wireless technology.

[0031] 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and other peripherals 138. It will be understood that the WTRU 102 may include any combination of the foregoing elements while remaining consistent with an embodiment. Also, embodiments contemplate that the base stations 114a and 114b and / or the nodes they may represent, such as, but not limited to, a transceiver station (BTS), a Node B, a site controller, an access point (AP), a Home Node B, an evolved Home Node B (eNodeB), a Home evolved Node B (HeNB), a Home evolved Node B gateway, and a proxy node, among others, may include some or all of the elements shown in FIG. 1B and described herein.

[0032] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors in association 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 may 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 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be appreciated that the processor 118 and the transceiver 120 may 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) over 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 an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It should be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0034] 1B shows the transmit / receive element 122 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. As such, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 115 / 116 / 117.

[0035] The transceiver 120 may be configured to modulate signals that may be transmitted by the transmit / receive element 122 and demodulate signals that may be received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. As such, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, for example.

[0036] The processor 118 of the WTRU 102 is coupled to and may receive user input data from 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). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The 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. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0037] The processor 118 may be configured to receive power from the power source 134 and distribute and / or control the power to other components within the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry 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 the like.

[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, information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 115 / 116 / 117 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of receiving signals from two or more nearby base stations. It should be appreciated that the WTRU 102 may obtain location information using any suitable location-determination method while remaining consistent with an embodiment.

[0039] The processor 118 may further be 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, the 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] 1C is a system diagram of the RAN 103 and the core network 106 according to one embodiment. As described above, the RAN 103 may employ UTRA radio technology for communicating with the WTRUs 102a, 102b, and 102c over the air interface 115. The RAN 103 may also communicate with the core network 106. As shown in FIG. 1C, the RAN 103 may include Node Bs 140a, 140b, and 140c, each of which may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 115. The Node Bs 140a, 140b, and 140c may each be associated with a particular cell (not shown) within the RAN 103. The RAN 103 may also include RNCs 142a and 142b. It will be understood that the RAN 103 may include any number of Node Bs and RNCs while remaining consistent with an embodiment.

[0041] As shown in FIG. 1C , Node Bs 140a, 140b may be in communication with RNC 142a. Additionally, Node B 140c may be in communication with RNC 142b. Node Bs 140a, 140b, and 140c may communicate with their respective RNCs 142a, 142b via an Iur interface. RNCs 142a, 142b may also communicate with each other via the Iur interface. Each of RNCs 142a, 142b may be configured to control its respective connected Node Bs 140a, 140b, and 140c. Additionally, each of RNCs 142a, 142b 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] 1C may comprise a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, and / or a gateway GPRS support node (GGSN) 150. While each of the foregoing 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] The RNC 142a in the RAN 103 may be connected to an MSC 146 in the core network 106 via an IuCS interface. The MSC 146 may be connected to an MGW 144. The MSC 146 and MGW 144 provide access for the WTRUs 102a, 102b, 102c to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and communication devices that use traditional landline communications.

[0044] The RNC 142a in the RAN 103 may also be connected to an SGSN 148 in the core network 106 via an IuPS interface. The SGSN 148 may be connected to a GGSN 150. The SGSN 148 and GGSN 150 may provide the WTRUs 102a, 102b, 102c access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

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

[0046] 1D is a system diagram of the RAN 104 and the core network 107 according to one embodiment. As mentioned above, the RAN 104 may employ E-UTRA radio technology for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the core network 107.

[0047] The RAN 104 may include eNodeBs 160a, 160b, and 160c, although the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, and 160c may implement MIMO technology, such that the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0048] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users on the uplink and / or downlink, and the like. As shown in FIG. 1D, the eNodeBs 160a, 160b, 160c may communicate with one another over an 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. Although each of the foregoing 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 MME 162 is connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may be used as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway upon initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

[0051] The serving gateway 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally perform routing and forwarding of user data packets to and from the WTRUs 102a, 102b, 102c. The serving gateway 164 may also perform other functions, such as anchoring the user plane during inter-eNodeB handovers, triggering paging when downlink data becomes available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and similar operations.

[0052] The serving gateway 164 may also be connected to a PDN gateway 166, which provides the WTRUs 102a, 102b, 102c access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0053] The core network 107 may facilitate communications with other networks. For example, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and communication devices that use traditional landlines. For example, the core network 107 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network 107 and the PSTN 108. Additionally, the core network 107 may enable the WTRUs 102a, 102b, 102c to access the networks 112, which may include other wired or wireless networks that may be owned and / or operated by other service providers.

[0054] 1E is a system diagram of the RAN 105 and the core network 109 according to one embodiment. The RAN 105 may be an access service network (ASN) that employs IEEE 802.16 wireless technology for the WTRUs 102a, 102b, 102c to communicate over the air interface 117. As described further below, the communication links between different functional entities of the WTRUs 102a, 102b, 102c, the RAN 105, and the core network 109 may be defined as reference points.

[0055] 1E, the RAN 105 may include base stations 180a, 180b, and 180c and an ASN gateway 182, although it should be appreciated that the RAN 105 may include any number of base stations and ASN gateways while remaining consistent with an embodiment. The base stations 180a, 180b, and 180c may each be associated with a particular cell (not shown) within the RAN 105 and may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c, respectively, over the air interface 117. In one embodiment, the base stations 180a, 180b, and 180c may implement MIMO technology. As such, the base station 180a may, for example, use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a. The base stations 180a, 180b, 180c may also provide mobility management functions such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement, and similar functions. The ASN gateway 182 may be used as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network 109, and similar functions.

[0056] The air interface 117 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an R1 reference point that implements the IEEE 802.16 specification. In addition, each of the WTRUs 102a, 102b, 102c may establish a logical interface (not shown) with the core network 109. The logical interface between the WTRUs 102a, 102b, 102c and the core network 109 may be defined as an R2 reference point that may be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0057] The communication link between each of the base stations 180a, 180b, 180c may be defined as an R8 reference point that comprises protocols for facilitating WTRU handovers and the transfer of data between base stations. The communication link between the base stations 180a, 180b, 180c and the ASN gateway 182 may be defined as an R6 reference point that may comprise protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

[0058] As shown in FIG. 1E, the RAN 105 may be connected to a core network 109. The communication link between the RAN 105 and the core network 109 may be defined as an R3 reference point, comprising protocols that facilitate data forwarding and mobility management functions, for example. The core network 109 may comprise a Mobile IP Home Agent (MIP-HA) 184, an Authentication, Authorization, and Accounting (AAA) server 186, and a gateway 188. While each of the foregoing elements may be illustrated 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 may be responsible for IP address management, enabling the WTRUs 102a, 102b, 102c to roam between different ASNs and / or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The AAA server 186 may be responsible for user authentication and user service support. The gateway 188 may facilitate interaction with other networks. For example, the gateway 188 may provide the WTRUs 102a, 102b, 102c with circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and communication devices using traditional landlines. In addition, the gateway 188 enables the WTRUs 102a, 102b, 102c to access the network 112, which may include other wired or wireless networks that may be owned and / or operated by other service providers.

[0060] 1E, it will be understood that the RAN 105 may be connected to other ASNs and the core network 109 may be connected to other core networks. The communication link between the RAN 105 and the other ASNs may be defined as an R4 reference point, which may include protocols for coordinating mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and the other ASNs. The communication link between the core network 109 and the other core networks may be defined as an R5 reference point, which may include protocols for facilitating interaction between a home core network and a visited core network.

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

[0062] Additionally, such multi-antenna transmission may be implemented and / or used for various purposes, including increasing peak system throughput, expanding cell coverage, and high-Doppler support. For example, single-user multiple-input multiple-output (SU-MIMO) may be used in such communication systems to increase the peak and / or average throughput of a user equipment (UE) or WTRU. Additionally, multi-user MIMO may be used in such communication systems to improve peak and / or average system throughput by exploiting multi-user diversity gain. Table 1 shows example MIMO functions that may be used in wireless communication systems to improve throughput, diversity gain, and the like.

[0063] [Table 1]

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

[0065] For example, a reference signal may be provided and / or used, e.g., along with CSI. In one embodiment, the reference signal may be provided or categorized as a WTRU- or UE-specific reference signal (WTRU- or UE-RS) and / or a cell-specific reference signal (CRS). According to one embodiment, a WTRU- or UE-RS may be used for a particular WTRU or UE such that the RS is transmitted on resources assigned to the WTRU or UE. Additionally, in one embodiment, a CRS may be a cell-specific reference signal that may be shared by each of the UEs in a cell such that the RS is transmitted over a wideband.

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

[0067] 2 illustrates an example embodiment for providing WTRU or UE-specific precoded DM-RS. As shown in FIG. 2, when precoded DM-RS is employed, the RS may be precoded using the precoding used for the data symbols, and a number K of RS sequences corresponding to the number of layers may be transmitted. In one embodiment, K is the number of physical antenna ports N T In addition, the K streams in Figure 2 may be assigned to a WTRU or UE, or shared with multiple UEs. If multiple UEs can share the K streams, co-scheduled UEs can share the same time / frequency resources at the same time.

[0068] As described above, a cell-specific reference signal (CRS) may be provided and / or used. According to one example embodiment, a CRS may be defined for UEs in a cell and used for demodulation and / or measurements. Additionally, in an example implementation, the CRS may be shared by UEs. In such an embodiment (e.g., because the CRS may be shared by UEs), a non-precoded RS may be used and / or employed, for example, to maintain uniform cell coverage. A precoded RS may have different cell coverage according to direction and / or due to beamforming effects. Figure 3 illustrates one example embodiment of a MIMO transmitter that may be used for non-precoded CRS transmission as described herein.

[0069] Additionally, in example embodiments, antenna virtualization may be implemented and / or used. For example, antenna virtualization may be used when the number of physical antenna ports and the number of logical antenna ports may differ (e.g., CRS and / or non-precoded CRS transmission as shown in FIG. 3). RS sequences may also be transmitted to antenna ports regardless of the number of streams.

[0070] According to example embodiments, different structures for the DM-RS and / or CRS may be implemented and / or used. Figure 4 illustrates an example embodiment of a DM-RS (e.g., antenna port-5) structure that may be used (e.g., in an LTE system) to support non-codebook-based transmission. In one embodiment, the structure illustrated in Figure 4 may be used at an eNB where, for example, antenna port-5 may be restricted to support one-layer transmission. In addition, antenna port-5 illustrated in Figure 4 is transmitted with CRS, and as such, RS overhead (e.g., overall) may increase.

[0071] FIG. 5 illustrates an example embodiment of a CRS structure according to or based on the number of antenna ports. The CRS patterns (e.g., shown in FIG. 5) for each antenna port may be mutually orthogonal in the time and / or frequency domain. As shown in FIG. 5, R0 and R1 may denote 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 located in REs from which CRS antenna ports may transmit may be muted.

[0072] According to an example embodiment, a predefined sequence (e.g., pseudorandom (PN), m-sequence, and the like) can be multiplied with the downlink RS, which can minimize inter-cell interference and / or improve channel estimation accuracy associated with the CRS. The PN sequence is applied at the OFDM symbol level within a subframe, and the sequence can be defined according to a cell ID, a subframe number, a position of the OFDM symbol, and the like. For example, the number of CRS antenna ports can be, for example, 2 in an OFDM symbol that can include 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 one such embodiment, the total number of CRSs for antenna ports in an OFDM symbol that can include an RS is 2×N RB This means that the sequence length is 2xN RB Additionally, in such an embodiment, N RB represents the number of RBs corresponding to the bandwidth, and the sequence can be binary or complex. The sequence r(m) is

[0073]

number

[0074] A complex sequence can be given as

[0075]

number

[0076] may represent the number of RBs corresponding to the maximum bandwidth in a communication system such as an LTE system,

[0077]

number

[0078] may be 110. In addition, c may represent a PN sequence with length −31, which may be defined as a Gold-sequence. When a DM-RS may be constructed, the formula

[0079]

number

[0080] is used, except that

[0081]

number

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

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

[0084] In some embodiments, two CDM groups may be used, for example, to multiplex up to four layers in each CDM group, allowing up to eight layers to be multiplexed in this pattern as a maximum. 4x4 Walsh spreading may also be used for the CDM multiplexing in each CDM group.

[0085] Additionally, since the DM-RS may be used for (e.g., limited to) demodulation performance, a CSI-RS that is sparse in time and / or frequency may be provided, for example, for measurements. The CSI-RS may be transmitted with a duty cycle of {5, 10, 20, 40, 80} ms, etc., within the PDSCH region. Additionally, up to 20 CSI-RS patterns may be available for reuse within a subframe. FIG. 7 illustrates an example embodiment of CSI-RS patterns that can be reused based on the number of ports (e.g., up to 20 CSI-RS patterns can be reused). In FIG. 7, the same pattern or shading with a corresponding TX number included therein or associated therewith 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, for example, 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 arrival 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 locations of the cells, the timing differences between them, which may be fixed, and / or other information, the network may derive the location 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 location and / or positioning. 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 the serving cell of the WTRU or UE in cases where the WTRU or UE may have one serving cell, which may be the case, 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., which may be the case, for example, in the presence of carrier aggregation. In one embodiment, the time difference of arrival may be measured based on known signals. By way of example (e.g., in the case of LTE), the WTRU or UE may use cell-specific reference symbols (CRS) for such measurements, and / or, for cells that may transmit a positioning reference signal (PRS), the WTRU or UE may use that PRS, for example. To perform positioning, the WTRU or UE may receive supporting information or assistance data, such as information associated with cells and / or signals to be measured. For OTDOA, the assistance data may include PRS-related parameters.In an example embodiment, support of OTDOA by a WTRU or UE may be optional, and the use of CRS or PRS for a given cell may be enabled and / or determined by the WTRU or UE implementation.

[0087] In one example embodiment, a positioning reference signal (PRS) may be transmitted by an eNB such that the eNB is aware of or knows the transmission parameters for the cells under its control. For a given cell, the PRS may be transmitted over N PRS may be defined to be provided or included in N consecutive downlink subframes, for example, PRS The first of the downlink subframes is

[0088]

number

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

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

[0091] Additionally, the PRS muting information may be signaled to the WTRU or UE in the positioning assistance data (e.g., the PRS muting information may be placed in the positioning assistance data and signaled along with that data). The first bit of the PRS muting sequence corresponds to the first PRS positioning occasion that may start after the start of a system frame number (SFN) that is zero (e.g., SFN=0), where the SFN may be the SFN of the OTDOA reference cell of the WTRU or UE.

[0092] FIG. 8 illustrates an example embodiment of an architecture that may be used for positioning. According to one embodiment, the architecture illustrated in FIG. 8 may be used in an LTE communication system, such as communication system 100 shown in FIGS. 1A and 1C-1E, to perform positioning for the LTE communication system. As shown in FIG. 8, positioning of or by a UE or WTRU may be controlled by an Enhanced Serving Mobile Location Center (E-SMLC). In an 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 may 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 FIG. 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 example embodiment, the eNB cannot verify what appears to be in the LPP message. Communications between the E-SMLC and the WTRU may go through a mobility management entity (MME) or SLP, which may direct communications to and / or from the appropriate WTRU, and may or may not verify the content of the communications and may or may not modify the content and / or transport of the communications. Communications may be possible or supported via the SLP and / or may be via SUPL bearers if the WTU or UE may be a SUPL-enabled terminal (SET).

[0093] Additionally, information that may be passed or exchanged between the WTRU or UE and the E-SMLC may include one or more of the following: the WTRU or UE's capability to support OTDOA positioning; instructions from the E-SMLC to perform OTDOA measurements; OTDOA positioning assistance data from the E-SMLC to the WTRU or UE, such as which cells are reference and / or additional or neighboring cells for OTDOA; and measurement reports from the WTRU or UE to the E-SMLC. The assistance data or other exchanged information may include information such as cell IDs and / or carrier frequencies, and / or PRS information for the reference and / or additional or neighboring cells. Since PRS transmission may be the responsibility 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 eNBs may be via an LPPa interface or protocol.

[0094] According to an example embodiment, a communication system may be provided with and / or use one or more transmission modes to transmit and / or receive information, data, and / or signals. Table 3 illustrates an example embodiment of transmission modes for a communication system (e.g., an LTE and / or LTE-Advanced system) that may be used to provide information and / or signals disclosed herein. The transmission modes provided in Table 3 (e.g., except for TM-7, 8, and 9 in one embodiment) may use CRS for both demodulation and measurements. Additionally, for TM-7 and 8 shown in Table 3, DM-RS may be used for demodulation and CRS may be used for measurements. According to an example embodiment, for TM-9 shown in Table 3, DM-RS and CSR-RS may be used for demodulation and measurements, respectively.

[0095] [Table 2]

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

[0097] [Table 3]

[0098] A downlink control channel may also be implemented and / or used. The downlink control channel may occupy the first one to three OFDM symbols in each subframe depending on the control channel overhead. This dynamic resource allocation for processing the downlink control channel overhead enables efficient downlink resource utilization, which may result in higher 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), may be transmitted within the downlink control channel region within each subframe. A downlink control channel resource unit may be defined as four consecutive REs in the frequency domain, referred to as a resource element group (REG), as shown in Figures 9 and 10. Figure 9 shows an exemplary REG definition within the downlink control channel region with a 2-Tx CRS. Figure 10 shows an exemplary REG definition within the downlink control channel region with a 4-Tx CRS. As shown, if the CRS may be located within the same OFDM symbol, a REG may be defined as four consecutive REs without a 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 in each subframe and / or indicate the number of OFDM symbols used for the downlink control channel in that subframe. Dynamic resource allocation for the downlink control channel at the subframe level may be enabled by using the PCFICH. A WTRU or UE may detect a control format indicator (CFI) from the PCFICH, and the downlink control channel region may be defined in the subframe according to the CFI value. Table 5 shows CFI codewords that may be detected from the PCFICH, and Table 6 details the downlink control channel resource allocation by CFI value, subframe type, and system bandwidth. In some embodiments, the PCFICH may be skipped if the subframe may be defined as a non-PDSCH-supportable subframe such that the WTRU or UE does not attempt 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 in a subframe, and / or the REGs may be uniformly distributed across the system bandwidth to exploit frequency diversity gain. The starting point of PCFICH transmission may vary according to physical cell ID (PCI), as shown in FIG. 11. A frequency shift of the PCFICH tied to the cell ID can achieve PCFICH detection performance by avoiding PCFICH collisions among multiple adjacent cells while achieving diversity order 4 from a distributed allocation. At a WTRU or UE receiver, a procedure (e.g., a first procedure) for downlink control channel detection may be decoding the PCFICH to calculate the number of OFDM symbols in a subframe. If downlink control resources may be defined by the PCFICH, a PCFICH detection error may result in a loss of downlink grants, uplink grants, and / or PHICH reception.

[0103] A Physical Hybrid ARQ Indicator Channel (PHICH) may be provided and / or used as described herein. In one embodiment, the PHICH may be used to transmit an ACK or NACK in response to a 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 higher layer signaling. The location of the PHICH resources may vary according to the duration of the PHICH.

[0104] 12 illustrates an exemplary PCFICH and PHICH resource allocation (e.g., PCFICH and PHICH REG allocation by PCI). As shown in FIG. 12, multiple PHICH groups are defined in a cell, and a PHICH group may include multiple PHICHs with orthogonal sequences, and the PHICH for a WTRU or UE is assigned to the lowest PRB index.

[0105]

number

[0106] and DM-RS cyclic shift (n DMRS ) and two index pairs (PHICH group index

[0107]

number

[0108] , PHICH sequence index

[0109]

number

[0110] ) may indicate the PHICH resource for a particular WTRU or UE.

[0111]

number

[0112] In this case, each index is

[0113]

number

[0114]

number

[0115] can be defined as, where:

[0116]

number

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

[0118]

number

[0119] where N g is the 2-bit information transmitted by the PBCH (Physical Broadcasting Channel), and this information is N g ∈{1 / 6, 1 / 2, 1, 2}.

[0120] Additionally, orthogonal sequences with spreading factors may also be provided and / or used, for example, as shown in Table 7.

[0121] [Table 6]

[0122] A physical downlink control channel (PDCCH) may be provided and / or used as described herein. For example, a PDCCH may be defined with one or more contiguous CCE resources (Control Channel Element), where one CCE may contain nine REGs. The number of available CCEs (N CCE ) is N CCE =[N REG / 9], where N REGmay be the number of REGs not allocated to the PCFICH or PHICH. Table 8-1 shows exemplary available PDCCH formats with definitions of a number of 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 may vary depending on the PDCCH format. The number of CCEs in a PDCCH format may be referred to as an aggregation level.

[0123] [Table 7]

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

[0125] [Table 8]

[0126] Aggregation levels {1, 2, 4, 8} may be supported in a WTRU or UE specific search space, and aggregation levels {4, 8} may be supported in a common search space.

[0127]

number

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

[0129]

number

[0130] The CCE corresponding to PDCCH candidate m is

[0131]

number

[0132] where Y k is defined as described herein and can be i=0,...,L-1. For a common search space, m'=m. Additionally, for a WTRU or UE specific search space and for a serving cell whose PDCCH may be monitored, if the monitoring WTRU or UE may be configured with a carrier indicator field, then m'=m+M (L) n C1 where n C1 may be the carrier indicator field value. Otherwise, if the monitoring WTRU or UE cannot be configured with the carrier indicator field, then m′=m, where m=0,...,M (L) -1 and M (L) may be the number of PDCCH candidates to monitor in a given search space. For a common search space, Y k may be set to 0 for the two aggregation levels L=4 and L=8. WTRU or UE specific search space at aggregation level L

[0133]

number

[0134] For variable Y k is Y k =(A Y k-1 ) mod D, where Y -1 =n RNTI ≠0, A=39827, D=65537, and

[0135]

number

[0136] and n s may be the slot number within the radio frame.

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

[0138] In one example embodiment, the PUCCH may be allocated relative to the PDCCH, e.g., the physical resources used for the PUCCH are given by higher layers:

[0139]

number

[0140] and / or

[0141]

number

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

[0143]

number

[0144] The variable σ may represent the bandwidth in terms of resource blocks that may be available for use by PUCCH format 2 / 2a / 2b transmissions in the respective slot.

[0145]

number

[0146] may represent the number of cyclic shifts used for PUCCH formats 1 / 1a / 1b in resource blocks used for a mix of formats 1 / 1a / 1b and 2 / 2a / 2b.

[0147]

number

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

[0149]

number

[0150] is an integer multiple of

[0151]

number

[0152] may be provided by higher layers. In one embodiment, the mixed resource block is

[0153]

number

[0154] In addition, there may be (e.g., at most) one resource block in each slot that supports a mix of formats 1 / 1a / 1b and 2 / 2a / 2b. The resources that may be used for transmitting PUCCH formats 1 / 1a / 1b, 2 / 2a / 2b, and 3 are denoted by non-negative indices.

[0155]

number

[0156] and

[0157]

number

[0158] and

[0159] A mapping to physical resources may be provided and / or used, for example, as described herein. In such an embodiment, a block of complex-valued symbols

[0160]

number

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

[0162]

number

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

[0164]

number

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

[0166]

number

[0167] and the antenna port number p can be defined.

[0168] Slot n S The physical resource blocks that can be used for transmitting the PUCCH in

[0169]

number

[0170] is given by where the variable m may 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] is.

[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 sounding reference signals and PUCCH formats 1, 1a, 1b, or 3, if one serving cell may be configured, a shortened PUCCH format may be used in which the last SC-FDMA symbol in the second slot of a subframe may be left empty.

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

[0179]

number

[0180] and mapped to antenna port p for PUCCH format 1a / 1b as described below using

[0181]

number

[0182] A HARQ-ACK transmission may be performed in subframe n for (eg, when one or more of the following may apply):

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

[0184]

number

[0185] can be used, where n CCE is the number of the first CCE used to transmit the corresponding DCI allocation (e.g., the lowest CCE index used to construct the PDCCH), and / or

[0186]

number

[0187] can be configured by higher layers. For two-antenna port transmission, the PUCCH resource for antenna port p1 is

[0188]

number

[0189] can be given by

[0190] For a PDSCH transmission of a primary cell for which a corresponding PDCCH is not detected in subframe n-4, the value

[0191]

number

[0192] For a WTRU or UE configured for two antenna port transmission, the PUCCH resource value may be set to two PUCCH resources and the first PUCCH resource for antenna port p0.

[0193]

number

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

[0195]

number

[0196] Otherwise, the PUCCH resource value can be mapped to a single PUCCH resource for antenna port p0.

[0197]

number

[0198] 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 for two antenna ports (p∈[p0, p1]) may be supported.

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

[0201]

number

[0202] Selected from A PUCCH Resources

[0203]

number

[0204] b(0)b(1) can be transmitted above, 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 The transport blocks and / or serving cells for the PUCCH resources may be given by a table.

[0205] A WTRU or UE configured in a transmission mode capable of supporting up to two transport blocks on serving cell c may use the same HARQ-ACK response for a transport block as a response to a PDSCH transmission over a single transport block or PDCCH indicating a downlink SPS release associated with serving cell c.

[0206] Additionally, the WTRU or UE may be associated with a HARQ-ACK(j), where 0≦j≦A-1, in accordance with one or more embodiments described herein (e.g., one or more of the following example embodiments). A PUCCH Resources

[0207]

number

[0208] can be determined.

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

[0210]

number

[0211] and for a transmission mode supporting up to two transport blocks, the PUCCH resource

[0212]

number

[0213] teeth,

[0214]

number

[0215] where n CCE is the number of the first CCE used to transmit the corresponding PDCCH, and

[0216]

number

[0217] can be configured by higher layers.

[0218] For a PDSCH transmission of a primary cell for which a corresponding PDCCH is not detected in subframe n-4, the value

[0219]

number

[0220] can be determined according to higher layer configuration. For transmission modes that support up to two transport blocks, the PUCCH resource

[0221]

number

[0222] teeth,

[0223]

number

[0224] can be given by

[0225] For PDSCH transmissions indicated by the detection of the corresponding PDCCH in subframe n-4 of the secondary cell, values ​​for transmission modes supporting up to two transport blocks

[0226]

number

[0227] and value

[0228]

number

[0229] may be determined according to higher layer configuration. The TPC field of the DCI format of the corresponding PDCCH may be used to determine the PUCCH resource value from one of the resource values ​​(e.g., four resource values) configured by higher layers. For a WTRU or UE configured for a transmission mode supporting up to two transport blocks, the PUCCH resource value may be determined from multiple (e.g., two) PUCCH resource values.

[0230]

number

[0231] Otherwise, the PUCCH resource value may be mapped to a single PUCCH resource

[0232]

number

[0233] can be mapped to

[0234] Resource allocation in carrier aggregation situations may be performed. For ePDCCH transmission, centralized and distributed resource allocation may be implemented to better support UEs with different channel conditions in a cell. Centralized resource allocation may allow frequency selectivity gain so that the eNB scheduler can increase spectral efficiency by utilizing channel state information for WTRUs or UEs experiencing low Doppler frequencies. Distributed resource allocation may specify frequency diversity gain so that reliable PDCCH transmission performance is achieved without channel state information, which may be appropriate for WTRUs or UEs experiencing the adverse effects of high Doppler frequencies. Currently, ePDCCH is designed based on a single component carrier, which may limit performance if 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 for frequency selective scheduling gain and / or frequency diversity gain, and the design of such ePDCCH can be single-component carrier oriented so that performance is limited in multi-carrier systems.

[0236] Additionally, the WTRU or UE may provide a HARQ-ACK response in subframe n+4 when the WTRU or UE receives the PDSCH in subframe n. Because blind detection of the PDCCH may want or require a portion of the period before starting to decode the PDSCH, the PDSCH processing time may be reduced to less than 4 ms. Time advancement may shorten the PDSCH processing time such that the WTRU or UE finishes its decoding process before n+4, for example, assuming the largest transport block size, highest rank, and / or longest time advance may be considered. That is, the PDSCH processing time may be further reduced. Because the ePDCCH may be transmitted in the PDSCH region, this may reduce the PDSCH processing time; for example, in a multi-carrier system, the maximum transport block size may be doubled. Similar processing time reductions may be observed for aperiodic CSI reporting. Aperiodic CSI reporting is triggered by the downlink control channel, and CSI feedback processing time is reduced by ePDCCH reception, which may become even more significant as the number of component carriers increases for simultaneous CSI reporting. Unfortunately, as described, the PDSCH processing time and aperiodic CSI reporting processing time at the WTRU or UE receiver may now be more stringent due to the use of ePDCCH instead of legacy PDCCH. These issues may become more severe if carrier aggregation is now used.

[0237] In addition, uplink control channel allocation 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 operation such as Rel-8 or R8). For more than one DL serving cell for FDD, PUCCH feedback can use PUCCH format 1b with channel selection (e.g., dynamically assigned PUCCH format 1b) (e.g., when two DL serving cells may be used) or PUCCH format 3 combined with ARI (e.g., semi-statically configured PUCCH format 3) (e.g., when more than two configured serving cells may be used). In TDD (e.g., Rel-10 TDD), single-cell operation may be based on PUCCH format 1 with channel selection (e.g., dynamically assigned PUCCH format 1). PUCCH format 1 with channel selection (eg, if more than one DL serving cell may be used) and / or PUCCH format 3 or PUCCH F3 may be used as a function of RRC configuration.

[0238] In one embodiment, for dynamically derived PUCCH resources, e.g., in the case of a single carrier operation or a DL assignment received on a primary serving cell with DL carrier aggregation, and for a PDSCH transmission indicated by detection of a corresponding PDCCH in subframe n-4 of the primary cell and / or for a PDCCH indicating downlink SPS release in subframe n-4 of the primary cell, the PUCCH resources may be:

[0239]

number

[0240] and / or for transmission modes supporting up to two transport blocks, the PUCCH resources may be

[0241]

number

[0242] teeth,

[0243]

number

[0244] However, n CCE is the number of the first CCE used to transmit the corresponding PDCCH, and

[0245]

number

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

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

[0248] Frame structure 2 TDD support may also be provided. In a TDD system, the PDSCH may be transmitted in a PDSCH region within a downlink subframe and / or in a PDSCH region within a subframe (e.g., DwPTS). In the DwPTS (e.g., a downlink pilot time slot in which a number of OFDM symbols are reserved for downlink transmission in a special subframe), the available number of OFDM symbols for PDSCH transmission may be limited and / or vary according to configuration. Because a legacy PDCCH may be transmitted together in the same subframe, an embodiment of ePDCCH transmission may be provided separately.

[0249] When multiple component carriers may be configured with different DL-UL subframe configurations in a TDD system, the downlink control channel may not be supported for a particular downlink subframe in the secondary cell, for example, when cross-carrier scheduling may be used. This may result in downlink subframes being wasted in the secondary cell. Because the number of OFDM symbols in the DwPTS may be insufficient and / or the number of OFDM symbols for PDSCH transmission may vary, ePDCCH transmission with the current subframe may 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 fallback may be provided. For example, when ePDCCH is supported over legacy PDCCH in the network, a WTRU or UE may be configured for a particular PDCCH type via higher layer signaling. In such an embodiment, there may be an ambiguity period 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 such an embodiment, where a WTRU or UE may be semi-statically configurable between legacy PDCCH and ePDCCH via higher layer signaling, the WTRU or UE may need to be able to receive the PDCCH continuously or continuously during the configuration process.

[0251] Resource conflicts may also occur between PRSs and ePDCCHs. For example, if ePDCCH is used in a cell, the PRS transmitted by the cell may overlap 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 conflict is shown in FIG. 15. As shown in FIG. 15, Vshift may be 0. Such overlap may 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 WTRUs or UEs can recognize the PRS transmissions, because the WTRUs or UEs support OTDOA, perform related measurements, and / or know the PRS information, for example, based on transparent communication between the WTRUs or UEs and the E-SMLC. Additionally, systems and / or methods for handling and / or avoiding such conflicts may be provided herein.

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

[0253] Configured resources 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 referred to as PRB pairs or RBs within a subframe, may be configured for ePDCCH transmission, and the ePDCCH resources may be provided to the WTRU or UE by using a broadcast channel (e.g., MIB, SIB-x) and / or higher layer signaling (e.g., PRC, MAC, and the like). The subset of PRBs may be contiguous or distributed PRBs. If the system bandwidth may be 5 MHz (e.g., if 25 PRBs are available),

[0254]

number

[0255] ), a subset of PRBs for ePDCCH

[0256]

number

[0257] may be constituted, provided that:

[0258]

number

[0259] 16 shows an example of ePDCCH multiplexing with PDSCH, where ePDCCH resources may be allocated within a subframe. PRB-level ePDCCH multiplexing with PDSCH may be used (e.g., as shown).

[0260] In one embodiment, ePDCCH PRBs may be reserved, for example, to enable simpler ePDCCH reception and / or reduced complexity of blind decoding. In addition, ePDCCH PRBs may be configured at a 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 indication by resource block group (RBG) that may be defined according to the system bandwidth; resource allocation type 1, which may be a bitmap-based indication by RBG subset; resource allocation type 2, which may be a contiguous 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, source allocation type 1 may be used for distributed allocation, and / or the RBs for centralized and distributed transmission may overlap, i.e., PRB pairs are used for centralized and distributed transmission. In addition, bitmap indication per PRB pair level may be used, and NDL,PRB A bitmap per PRB level is provided to indicate the ePDCCH resources that can use the N bits, DL,PRB may 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 signaled to the WTRU or UE. Each PRB pair subset may include one or more PRB pairs, and the PRB pairs included in a PRB pair subset may be mutually orthogonal with other PRB pair subsets. At least one of the PRB pair subsets may be used without configuration. The PRB pair subset may be used for a common search space or may be used for a first PRB pair subset for a WTRU- or UE-specific search space. The number of subsets may be dynamically signaled to the WTRU or UE. For example, the number of subsets may be indicated in each subframe in which the WTRU or UE can monitor or receive the ePDCCH. Predefined PRBs may be used for the common search space. Configuration-based PRBs may be used for the WTRU- or UE-specific search space. The ePDCCH PRB embodiments described herein may be used for each ePDCCH resource set when multiple ePDCCH resource sets may be configured for a WTRU or UE. The terms ePDCCH resource set and ePDCCH region may be used interchangeably.

[0261] According to one example embodiment, a WTRU or UE may have a specific behavior for monitoring the ePDCCH based on a given ePDCCH indication. For example, the ePDCCH resources may be signaled to the WTRU or UE via a broadcast channel and / or RRC signaling. The WTRU or UE may monitor the ePDCCH within its search space, which may be within a subset of PRBs configured for the ePDCCH. The subset of PRBs may be signaled to the WTRU or UE implicitly or explicitly in a dynamic indication. For example, an indication bit may be transmitted in a subframe and / or a DM-RS scrambling sequence may indicate which subset of PRBs configured for the ePDCCH may be used. The ePDCCH resources may be signaled to the WTRU or UE by an ePDCCH resource index (ERI) from a set of ePDCCH configurations, and / or the ERI may be signaled via higher layer signaling or implicitly derived from at least one of 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 informed about the type of ePDCCH resource, such as a “system ePDCCH resource” and / or a “WTRU- or UE-specific ePDCCH resource.” WTRU or UE behavior 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 higher layer signaling. The WTRU or UE may receive WTRU- or UE-specific ePDCCH resource information from higher layer signaling. The WTRU- or UE-specific ePDCCH resources may be the same as the system ePDCCH resources. A WTRU- or UE-specific ePDCCH resource may be a subset of the 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 a WTRU- or UE-specific ePDCCH resource.In some embodiments, a WTRU or UE cannot receive (e.g., cannot expect to receive) a PDSCH in system ePDCCH resources that cannot be within WTRU or UE specific ePDCCH resources. A WTRU or UE can receive (e.g., can expect to receive) a PDSCH in system ePDCCH resources that cannot be within WTRU or UE specific ePDCCH resources. A WTRU or UE can receive (e.g., can expect to receive) a PDSCH in WTRU or UE specific ePDCCH resources if the ePDCCH cannot be transmitted in an ePDCCH PRB pair.

[0262] According to one example embodiment, the ePDCCH PRBs may be configured in multiple steps, such as long-term and short-term ePDCCH resources. For example, the long-term ePDCCH resources may be semi-statically defined and / or the short-term ePDCCH resources may be dynamically defined within the long-term ePDCCH resources. Also, the terms long-term ePDCCH resources, cell-specific ePDCCH resources, semi-static ePDCCH resources, temporal ePDCCH resources, and / or higher layer configured ePDCCH resources 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 indicate a set of PRB pairs as a long-term ePDCCH resource. A number of bits (e.g.,

[0264]

number

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

[0266] The 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. The short-term ePDCCH resources may be a subset of the long-term ePDCCH resources. The subset of ePDCCH resources may be indicated within each subframe to allow the eNB to change the subset of ePDCCH resources from one subframe to another.

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

[0268] The indication of the short-term ePDCCH resource may be based on implicit signaling. The implicit signaling may be a DM-RS in a PRB pair configured as a short-term ePDCCH resource, which may be scrambled with a specific scrambling code that may be known to the eNB and / or the WTRU or UE. Thus, the WTRU or UE may check the long-term ePDCCH resource with the specific scrambling code and calculate the short-term ePDCCH resource. After the WTRU or UE finishes calculating (e.g., determining) the short-term ePDCCH resource, a WTRU- or UE-specific search space may be defined with the short-term ePDCCH resource. Thus, the WTRU or UE may monitor the ePDCCH within the WTRU- or UE-specific search space. The short-term resource may be configured in a WTRU- or UE-specific manner. The WTRU or UE may assume that a PDSCH cannot be transmitted in a PRB pair configured for a long-term ePDCCH resource, even though, for example, the PRB pair may not be within the short-term ePDCCH resource. The short-term resources may be configured in a cell-specific manner. A WTRU or UE may receive a PDSCH on a PRB pair configured for a long-term ePDCCH resource, for example, when the PRB pair may not be within the short-term ePDCCH resource.

[0269] Multiple ePDCCH resource sets are presented or described herein, and / or a subset of the 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 system configuration. The subset of ePDCCH resource sets may be configured for a particular WTRU or UE as a WTRU- or UE-specific search space. The subset of ePDCCH resource sets for a particular WTRU or UE may be predefined as a function of C-RNTI and / or subframe number. For example, the N number of ePDCCH resource sets may be ePDCCH If subsets of ePDCCH resource sets are defined and one of the subsets of ePDCCH resource sets may be configured for a particular WTRU or UE, the following formula may be used to select which ePDCCH resource set may be used for the WTRU or UE: The subset of ePDCCH resource sets for a particular WTRU or UE is k=n RNTI mod N ePDCCH Table 8-3 shows an example of a subset configuration when four ePDCCH resource sets can be defined. In the table, "v" may indicate a set that can be included in the subset. In addition, k=n RNTI mod3 may be used in Table 8-3.

[0270] [Table 9]

[0271] An ePDCCH resource set may comprise one or more PRB pairs, and / or the number of PRB pairs per ePDCCH resource set may be fixed. set PRB pairs are grouped as an ePDCCH resource set, and N set The PRB pairs may be contiguous or distributed across the system bandwidth.

[0272] In addition, an ePDCCH resource set may be configured as a centralized ePDCCH resource or a distributed ePDCCH resource. If an ePDCCH resource set is defined as a centralized ePDCCH resource, an eCCE in the ePDCCH resource set may be defined as a centralized ePDCCH transmission (LeCCE). Multiple LeCCEs may be defined in one ePDCCH resource set. REs for an LeCCE may be arranged within a PRB pair. If an ePDCCH resource set is defined as a distributed ePDCCH resource, an eCCE in the ePDCCH resource set may be defined as a distributed ePDCCH transmission (DeCCE). Multiple DeCCEs may be defined in an ePDCCH resource set. REs for a DeCCE may be arranged across two or more PRB pairs. A DeCCE may include multiple eREGs, and an eREG may comprise multiple REs within a PRB pair. Multiple eREGs for a DeCCE may be transmitted on multiple PRB pairs in the ePDCCH resource set. The first ePDCCH resource set may be predefined as distributed ePDCCH resources and / or the other ePDCCH resource sets may be configured as one of centralized ePDCCH resources and distributed ePDCCH resources.

[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] In this case, one or more of the following may apply:

[0278]

number

[0279] where N s may be a fixed number or an eNB configured number, and the function for the number of PRB pairs per set may be different for ePDCCH transmissions such as centralized and distributed ePDCCH, and / or the look-up table may be

[0280]

number

[0281] According to N set can be defined in terms of N set The values ​​of may differ from those shown in Table 8-4 below.

[0282] [Table 10]

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

[0284] A subset of multiple ePDCCH resource sets may also be explicitly selected (e.g., using one or more indication bits). For example, the one or more indication bits may be transmitted in a PDCCH region within the same subframe. In this embodiment, at least one of a PCFICH or a DCI within the PDCCH region may be transmitted for indication bit transmission. A PCFICH within 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 according to the same number indicated in the PCFICH or configured via higher layer signaling. The DCI may be defined and / or transmitted within a common search space. The DCI may include at least one of multiple ePDCCH resource sets and / or a resource allocation index.

[0285] One or more indication bits may be transmitted in the same subframe or a previous subframe within the PDSCH region. In this case, an indication channel may be transmitted for the indication transmission. The indication channel (e.g., ePCFICH) may be defined and / or transmitted at a specific location. The location for the indication channel may be the zero-power CSI-RS or a subset RE of the 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 the duty cycle. The indication channel may be defined in the first ePDCCH resource set. The indication channel may be transmitted in the Nth subframe or the Nth subframe. set On PRB pairs, for example, N set The indication channel may be transmitted when PRB pairs can be used for the first ePDCCH resource set. The indication channel may be defined at a fixed location within a subframe and / or the location may change depending on the cell ID and / or subframe number. The indication channel may be transmitted in subframe n-1 and / or the indication information may apply in subframe n.

[0286] A subset of multiple ePDCCH resource sets may be implicitly selected. For example, a specific DM-RS scrambling sequence may be used for a subset of the ePDCCH resource sets used for ePDCCH transmission in a subframe. The WTRU or UE may detect the ePDCCH resource set used for ePDCCH transmission in a subframe, for example, by using the scrambled sequence for the DM-RS. After the WTRU or UE finishes detecting the ePDCCH resource set, the WTRU or UE may calculate a WTRU- or UE-specific search space. The WTRU or UE may start blind detection within the WTRU- or UE-specific search space.

[0287] Multiple ePDCCH resource sets, which may be used interchangeably as ePDCCH regions, ePDCCH PRB sets, and / or ePDCCH sets, may be implemented. Each ePDCCH resource set may have N non-overlapping regions. set PRB pairs, where N set can take on one or more values. In this embodiment, each ePDCCH resource set can be configured as a centralized ePDCCH transmission or a distributed ePDCCH transmission. N set Also, or alternatively, may be configured via higher layer signaling, predefined as a function of system parameters, and / or defined as a combination of system parameters and higher layer signaling.

[0288] K set K ePDCCH resource sets are also configured for the WTRU or UE, where K set can have a value equal to or greater than 2. In this embodiment, N for each ePDCCH resource set set is K set n ePDCCH resource sets can be configured and used independently, set is configured via higher layer signaling, and K setis indicated in the broadcasting channel (e.g., MIB, SIB-x) and / or K set may vary depending on the SFN / subframe index.

[0289] N for each ePDCCH resource set set may be used independently, one or more of the following may apply: N set is larger for concentrated transmission so that frequency selective scheduling gain increases while reasonable resource utilization can be presented, and N set is larger for distributed transmission so that the frequency diversity gain is maximized, and N set 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), e.g., N set is predefined for centralized transmission by the system bandwidth, while N set is configured for distributed transmission via higher layer signaling, and / or N set,1 and N set,2 Two N such as set But, K set is configured when is greater than 1, and N set,1 is used for the ePDCCH resource set configured as distributed transmission, while N set,2 may be used for all configured ePDCCH resource sets as a centralized transmission.

[0290] K set The ePDCCH resource sets may be configured as a single ePDCCH resource set or multiple ePDCCH resource sets. If a WTRU or UE may be configured with multiple ePDCCH resource sets, the WTRU or UE may set= 2. In this embodiment, if a WTRU or UE may be configured with a single ePDCCH resource set, the ePDCCH resource set may be configured for centralized or distributed ePDCCH transmission, and / or the WTRU or UE may assume that the ePDCCH resource set may be configured for distributed transmission. If a WTRU or UE may be configured with multiple ePDCCH resource sets, at least one of the ePDCCH resource sets may be configured for distributed ePDCCH transmission, the ePDCCH resource set may be defined as primary ePDCCH resources and the other ePDCCH resource sets may be defined as secondary ePDCCH resources, and / or N set may vary depending on the ePDCCH resource set. For example, the first set may have N set = 4, and the second set has N set =2.

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

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

[0293] Additionally, in subframes containing PSS / SSS and / or PBCH, the location of the ePDCCH common search space may be located next to the center six PRB pairs when 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 center six PRB pairs.

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

[0295] The WTRU- or UE-specific search space may be configured 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 multiple PRBs. For example, one of {2, 4, 8} PRBs may be configured as a WTRU- or UE-specific ePDCCH resource set via higher layer signaling. In addition, a bitmap may be used to indicate the PRB pairs that are configured in the common search space. In one embodiment, up to two WTRU- or UE-specific ePDCCH resource sets are configured per WTRU or UE, and the two WTRU- or UE-specific ePDCCH resource sets may partially or fully overlap in a PRB pair.

[0296] Furthermore, the PRB pairs for the WTRU- or UE-specific search space and the PRB pairs for the common search space may overlap. In this embodiment, one or more of the following may apply: The second ePDCCH common search space resource set overlaps with the 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 may be configured, the two ePDCCH common search space resource sets may fully or partially overlap each other.

[0297] Resource configuration embodiments for TDD in a single DL carrier embodiment may be described herein. In frame structure 2, several UL-DL subframe configurations and associated HARQ-ACKs and UL / DL grants may be defined, e.g., to fully utilize UL / DL resources. Table 9 shows example UL-DL subframe configurations that may allow for various uplink-downlink traffic asymmetries according to the network environment.

[0298] [Table 11]

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

[0300] [Table 12]

[0301] Because the ePDCCH may be transmitted based on antenna ports 7 through 40, the ePDCCH may not be transmitted in the special subframe configuration. In such a case, the WTRU or UE's behavior with respect to PDCCH reception may be as described herein. For example, the WTRU or UE may assume that the ePDCCH may be restricted to transmission in normal downlink subframes. The WTRU or UE may assume that the downlink control channel may be transmitted via a legacy PDCCH in special subframes regardless of the PDCCH configuration. The WTRU or UE may assume that it receives an ePDCCH targeting special subframe n in downlink subframe n, where k is defined according to the UL-DL subframe configuration and k is defined as the downlink subframe closest to subframe n. If the WTRU or UE is configured to receive the ePDCCH, the WTRU or UE may skip blind decoding of the ePDCCH in the special subframe. ePDCCH and legacy PDCCH reception may be configurable, for example, as shown in the example 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 the 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), the ePDCCH may be transmitted and / or monitored in the special subframe configurations {1, 2, 3, 4, 6, 7, 8} in Table 10 (e.g., for such TDD and / or downlink normal CP, it may not be transmitted and / or monitored in configurations 0 and 5). The special subframe configurations in which the ePDCCH may be transmitted may be predefined as other than {1, 2, 3, 4, 6, 7, 8}. For example, the ePDCCH may be transmitted and / or monitored in a DwPTS that includes more than m OFDM symbols, where m is 3, 8, 9, or 10. Additionally, if special subframe configurations 0 or 5 may be used in a cell, the WTRU or UE behavior with respect to PDCCH reception may be defined in one or more of the following ways. The WTRU or UE may assume that the 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 the ePDCCH in the special subframe; the WTRU or UE may assume that the ePDCCH targeting special subframe n is transmitted in subframe nk, where k may be defined as the downlink subframe closest to subframe n; the WTRU or UE may assume that the PDCCH may be transmitted via a legacy PDCCH in the special subframe; and / or the WTRU or UE may follow the configuration of the ePDCCH and the legacy PDCCH, which may be predefined. If special subframe configurations other than 0 and 5 may be used in the cell, the WTRU or UE may assume that the ePDCCH may be transmitted at DwPTS. If DwPTS is N, DwPTS There can be special subframes that can be longer than [OFDM symbol]. DwPTScan be configured by higher layers. DwPTS may be fixed at 9 (e.g., 19760 T for normal CP). s and for extended CP it is 20480 T s (You can take it to be equal to .)

[0304] When multiple component carriers may be configured in TDD mode, each component carrier may have a different UL-DL subframe configuration. For example, a PCell and an SCell may be configured with UL-DL configurations 1 and 2, respectively, as shown in FIG. 17. FIG. 17 illustrates an example embodiment of carrier aggregation with different TDD UL-DL configurations. In such a case, although downlink subframes for the PCell may not be available in subframes 3 and 8, a WTRU or UE may expect to receive a PDSCH on an SCell, which may result in scheduling limitations when cross-carrier scheduling may be activated because the WTRU or UE can receive a PDCCH on the PCell. At least one of the WTRU or UE operations described herein may be used when cross-carrier scheduling is activated, which can resolve such issues. For example, a WTRU or UE may assume that a PDCCH may be transmitted on an SCell when normal downlink subframes may not be available on the PCell in the SCell downlink. A WTRU or UE may monitor the ePDCCH on the SCell for PDCCH reception regardless of the PDCCH configuration. A WTRU or UE may monitor the legacy PDCCH if the WTRU or UE may be configured to receive the legacy PDCCH on the PCell. A WTRU or UE may monitor the legacy PDCCH or ePDCCH according to the subframe with a predefined PDCCH reception configuration. A WTRU or UE may assume that a PDCCH may be transmitted on the SCell when a normal downlink subframe or a special subframe may not be available on the PCell in an SCell downlink subframe. A WTRU or UE may continue to monitor the PDCCH in a special subframe if the special subframe configuration is not 0 or 5.If special subframe configuration 0 or 5 may be used, the WTRU or UE may assume that the PDCCH may be transmitted on an SCell. If multiple SCells may be configured, the SCell with the lowest frequency placement may be considered the PCell for PDCCH reception.

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

[0306] The ePDCCH resources may be restricted to configuration in the primary cell (PCell) when cross-carrier scheduling may be activated. In such a case, the WTRU or UE may assume that the ePDCCH may be restricted to transmission on the PCell, and the WTRU or UE may restrict monitoring of ePDCCH reception to the PCell. The ePDCCH resources may not be allowed on the secondary cell (SCell). In addition, the ePDCCH resources on the SCell may be considered as muted RBs from the WTRU or UE's perspective, such that the WTRU or UE performs rate matching for the RBs when the PDSCH may be scheduled in the RBs.

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

[0308] The ePDCCH resources may be defined in a subset of component carriers, which may be equal to or smaller than the configured component carriers for a particular WTRU or UE. The subset of component carriers may be configured by higher layers. In addition, the subset of component carriers may be predefined, for example, to include a component carrier number and a center frequency. The subset of component carriers may also be dynamically changed from one subframe to another. The pattern of the subset may be predefined and / or tied to the SFN number.

[0309] In one embodiment, the ePDCCH and the 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 may monitor the ePDCCH on the component carriers configured for ePDCCH and the legacy PDCCH on the other component carriers.

[0310] The ePDCCH frequency diversity mode is defined interchangeably and may not be limited to ePDCCH distributed transmission, ePDCCH frequency diversity scheme, ePDCCH distributed mode, and / or mode-1. For the ePDCCH frequency diversity mode (e.g., distributed mode, mode-1, etc.), resources for the ePDCCH may be distributed across the system frequency bandwidth to obtain frequency diversity gain. The ePDCCH resources for the frequency diversity mode may be configured as described herein. For example, enhanced control channel elements (eCCEs) and / or enhanced resource group elements (eREGs) may be distributed across multiple downlink carriers (e.g., DL cells), and the ePDCCH may be transmitted by using {1, 2, 4, or 8} eCCEs, where the eCCEs are N eREGs The size-N may include: size-N = 1; size-N = 2; size-N = 3; size-N = 4; size-N = 5; size-N = 6; size-N = 7; size-N = 8; size-N = 9; size-N = 10; size-N = 11; size-N = 12; size-N = 13; size-N = 14; size-N = 15; size-N = 16; size-N = 17; size-N = 18; size-N = 19; size-N = 20; size-N = 21; size-N = 22; size-N = 23; size-N = 24; size-N = 25; size-N = 25; size-N = 26; size-N = 27; size-N = 28; size-N = 39; size-N = 39; size-N = 39; size-N = 40; size-N = 41; size-N = 42; size-N = 50; size-N = 51; size-N = 52; size-N = 53; size-N = 54; size-N = 55; size-N = 56; size-N = 57; size-N = 58; size-N = 59; size-N = 60; size-N = 61; size-N = 62; size-N = 63; size-N = 64; size-N = 65; size-N = 66; size-N = 67; size-N = 68; size-N = 69; size-N = 70; size-N = 71; size-N = 72; size-N = 73; size-N = 74; size-N = 75; size-N = 76; size-N = 77; size-N = 78; size

[0311] The ePDCCH frequency selective mode is defined interchangeably and may not be limited to ePDCCH centralized transmission, ePDCCH frequency selection scheme, ePDCCH centralized mode, and / or Mode-2. For the ePDCCH frequency selective mode (e.g., centralized mode, Mode-2, and the like), resources for the ePDCCH may be arranged within one or two RBs according to the eCCE aggregation level to obtain frequency selectivity gain. The ePDCCH resources for the frequency selective mode may be configured as described herein. For example, an eCCE may be arranged within the same PRB pair when multiple eCCEs may be aggregated. eREGs arranged within the same PRB pair and / or adjacent PRB pairs may be aggregated to form an eCCE. The ePDCCH Mode-2 may be configured within a central 5 MHz (e.g., 25 PRB) bandwidth.

[0312] In a multiple component carrier system, ePDCCH mode-1 (e.g., ePDCCH frequency diversity mode) and / or ePDCCH mode-2 (e.g., ePDCCH frequency selection mode) may be configured as described herein. For example, a WTRU or UE may monitor ePDCCH mode-2 in a PCell and ePDCCH mode-1 in other configured cells when cross-carrier scheduling may not be activated. A WTRU or UE may monitor ePDCCH mode-1 and / or ePDCCH mode-2 in a PCell when cross-carrier scheduling may be activated. A subset of ePDCCH mode-1 and / or ePDCCH mode-2 resources may be defined as ePDCCH mode-3, which may span multiple PRBs in the center frequency bandwidth.

[0313] The ePDCCH resource set is N set PRB pairs can be defined within a cell such that they can be placed within the cell. For example, setePDCCH resource sets may also be configured within a cell. set and / or K set may be defined for each cell when multiple component carriers may be used. Cell may also be used interchangeably as component carrier, PCell, or SCell. In this case, K set At least one of the sets is defined as ePDCCH distributed transmission, and / or K set may be defined as centralized ePDCCH transmission or distributed ePDCCH transmission in the SCell.

[0314] In addition, the ePDCCH resource set is N set PRB pairs may be defined on multiple component carriers such that they may be located on multiple component carriers. In this case, if the ePDCCH resource set may be configured as a distributed transmission, N PRB pairs for the ePDCCH resource set may be defined on multiple component carriers such that the N PRB pairs may be located on multiple component carriers. set If the PRB pairs are located on multiple component carriers and / or the ePDCCH resource set can be configured as a centralized transmission, N PRB pairs for the ePDCCH resource set set The PRB pairs may be located in the same cell.

[0315] An extended resource element group (eREG) may also be provided as described herein. A minimum resource unit for the 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, where the number of REs may vary depending on at least one of an eREG number, a subframe number and / or a subframe type (e.g., an MBSFN subframe), a CSI-RS configuration including zero-power CSI-RS, a PRS configuration, the presence of SSS / PSS, and / or similar factors. An eREG may be formed by available REs in a given time / frequency resource grid, such as NxM REs in a PDSCH region that does not include zero-power and non-zero-power CSI-RS, SSS / PSS, and / or one or more (e.g., each or a subset) of the PBCH, PRS, DM-RS, CRS, ePHICH, ePCFICH, and / or the like.

[0316] The time and / or frequency resource grid within the PDSCH region (NxM RE) for eREG may be provided and defined in at least one of the following ways: N and M indicate the RE granularity in frequency and time, respectively, 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), N may be configurable by broadcasting (e.g., MIB or SIB-x) and / or RRC configuration, and N may be different within a subframe for centralized transmission (ePDCCH mode-1) and distributed transmission (ePDCCH mode-2) (e.g., a smaller number of N is used for distributed transmission (ePDCCH mode-3)). dist ) and / or a large number of N are used for centralized transmission (N local ), but N local >N dist M is usually 14-N in CP. PDCCH , 12-N for extended CP PDCCH where N PDCCHmay represent the number of OFDM symbols used for legacy PDCCH and indicated by PCFICH in a subframe, M may be defined as a fixed number such as 11 for normal CP and 9 for extended CP, M may be configurable by broadcasting (e.g., MIB or SIB-x) and / or RRC configuration, and M may be different 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 centralized transmission (M local ), but M local >M dist (This may be considered as such.)

[0317] In one embodiment, an eREG may be formed by a fixed or variable number of REGs, where a REG may be defined as four consecutive REs within a PDSCH region that is not used for other purposes but is used for the ePDCCH as disclosed herein. For example, one eREG may include nine REGs, which may make the eREG similar to a CCE (e.g., simplifying the evolution of standardized terminology from the PDCCH used).

[0318] FIG. 19 illustrates an example embodiment of the definition of eREG. For example, FIG. 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 portion of FIG. 19 and ports 7-8 in the right portion of FIG. 19). As shown in FIG. 19, N=1 and M=11 can be used in subframes that do not include CSI-RS and PSS / SSS. eREG spans both slots in a PRB pair, and the number of REs for eREG can vary depending on the eREG number due to CRS and DM-RS. For example, eREG#n can include 3 REs, and eREG#n+2 can include 11 REs depending on the presence of DM-RS and CRS (e.g., as shown in the left portion of FIG. 19). Also, fully FDM-based eREG multiplexing can be used to flexibly utilize power for unused eREGs. For example, if eREG#n+7 cannot be used, power can be reused to boost up the power of eREG#n+2.

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

[0320] A fixed number of eREGs may be defined for each PRB pair configured as an ePDCCH resource. For example, 16 eREGs may be defined for each PRB pair, regardless of the configuration of the reference signal, subframe type, CP length, etc. The eREGs may be defined in an interlaced manner such that REs other than those within a PRB pair are assigned cyclically to eREGs 0 to 15 in frequency order. If 16 eREGs may be available for each PRB pair, then 16×N set eREG is N set may be available for an ePDCCH resource set having PRB pairs.

[0321] In one embodiment, eREG subset blocking may be used such that a subset of eREGs in an ePDCCH resource set is blocked and not used to form eCCEs, which may enable improved or better inter-cell interference coordination since non-overlapping eREGs may be used between adjacent cells.

[0322] For eREG subset blocking, 16 × N set A subset of eREGs among them is indicated via higher layer signaling, and this subset may not be counted as eREGs. Therefore, physical eREGs and virtual eREGs may be defined. Virtual eREGs may be used to form eCCEs. Therefore, the number of physical eREGs may be less than or equal to the number of virtual eREGs. The subset of eREGs may be predefined in the form of eCCEs, PRB pairs, and / or ePDCCH resource sets. Therefore, the indication may be based on the eCCE number, PRB pair number, and / or ePDCCH resource set number. The subset of eREGs may be predefined as a table, with indexes corresponding to the subset of eREGs. A bitmap may be used to indicate the subset of eREGs that may be blocked.

[0323] The subset of eREGs 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 eREGs may be predefined with indices, 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 defined as J sub For eREG #n, J is defined as a subset sub can be defined modulo J subFor n mod 4 = 4, the subsets may be defined as index-0:subset0={eREGs that satisfy n mod 4=0}, index-1:subset1={eREGs that satisfy n mod 4=1}, index-2:subset2={eREGs that satisfy n mod 4=2}, and / or index-3:subset3={eREGs that satisfy n mod 4=3}. If the subsets of eREGs for blocking may be defined as a function of one or more system parameters, the subset index may be implicitly dictated by at least one of the system parameters. For example, the subset index may be defined by a modulo operation of the cell-ID (e.g., index-i, where i may be defined as cell-ID mod 4).

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

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

[0326] Additionally, according to one example embodiment, when an ePDCCH common search space may be monitored in a subframe together with an 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 starting symbol of the WTRU- or UE-specific search space may be the same as the starting symbol for the ePDCCH common search space. Furthermore, the starting symbol of the ePDCCH WTRU- or UE-specific search space may be configured as a function of the CFI value at the starting symbol of the PCFICH and ePDCCH common search space. The starting symbol of the ePDCCH WTRU- or UE-specific search space may be configured independently via higher layer signaling, regardless of the starting symbol of the ePDCCH common search space. Additionally, in one embodiment, the starting symbol of 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, the WTRU or UE may assume the same starting symbol of the ePDCCH common search space or may follow or use a starting symbol value configured by higher layer signaling. In particular, according to one embodiment, if the WTRU or UE may be configured in a legacy transmission mode (e.g., TM1-9), the starting symbol of the WTRU- or UE-specific search space may be the same as the starting symbol of the ePDCCH common search space in a subframe, and if the WTRU or UE may be configured in another transmission mode (e.g., TM10 (CoMP transmission mode)), the WTRU or UE may follow or use a starting symbol value configured via higher layer signaling.

[0327] The starting symbol of the ePDCCH common search space may be further configured or defined based on at least one of the following: According to one example embodiment, the WTRU or UE may implicitly detect the starting symbol of the ePDCCH common search space by decoding the PCFICH in the respective subframe. In addition, the fixed starting symbol may be N pdcchThe starting symbol of the ePDCCH common search space may be predefined by assuming that N OFDM symbols may be occupied for the legacy PDCCH. As such, the starting symbol of the ePDCCH common search space may be N pdcch +1. The number of OFDM symbols for the PDCCH may be N pdcch For certain carrier types (e.g., new carrier types where CRS may not be transmitted in one or more subframes, e.g., in subframes other than the subframe containing the PSS / SSS), the WTRU or UE may determine whether the number of OFDM symbols for the PDCCH is N pdcch = 0. In one such embodiment, the common search space starting symbol may be broadcast on the PBCH or SIB-x such that the starting symbol indicated on the broadcasting channel is used for demodulating ePDCCH candidates within the ePDCCH common search space.

[0328] Enhanced Control Channel Elements (eCCEs) may be described herein. For a given subframe i, an eCCE containing a number of eREGs may be N eREGs (i), and 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] Assume that:

[0331] The first category is considered, in which the number of available REs for the jth eREG (e.g., K REs(i,j)) may vary with some REs for other purposes, such as reference signals, PDCCH, PSS / SSS, and the like, 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 may be fixed per eCCE (e.g., N eREGs = 4), so the starting points of the eCCEs can be easily determined (e.g., the starting points of the eCCEs may be the same). eREGs The available RE may change since a fixed N per eCCE may be used. eREGs To increase the coverage in number, one or more of the following may be used and / or applied: For example, the transmit power per eCCE may be defined as a function of the available number of REs, and the reference number of REs per eCCE may be N eCCE For example, N eCCE = 36, and the number of REs available for a particular eCCE is K REs = 18, the additional transmit power added from the original transmit power is

[0333]

number

[0334] From the predefined power boosting rule, 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 N may be defined differently according to the ePDCCH transmission type and / or search space type. For example, for a concentrated transmission, N eREGs = 3 is used, and for distributed transmission, N eREGs = 4 can be used. For concentrated transmission, a smaller N eREGsmay be used because beamforming gain and / or frequency selective scheduling may be performed for centralized transmission. Distributed transmission may rely on frequency diversity gain through channel coding. eREGs Different values ​​of N may be used for the common search space and the WTRU or UE specific search space. For example, for the common search space, eREGs = 6 is used, and N eREGs = 4 may be used. The eCCE aggregation level within the ePDCCH search space varies depending on the subframe, and the aggregation level may be implicitly derived from the reference signal configuration for a particular subframe. The aggregation level is a positive integer number N AL For example, the search space for a WTRU or UE may be defined as a function of N AL {1, 2, 4, 8}. N AL = 2, the WTRU or UE may need to monitor the ePDCCH at aggregation level 2, e.g., {1, 2, 4, 8} = {2, 4, 8, 16}. AL N may be configured by higher layers according to the subframe, or may be implicitly defined according to the configuration of the subframe containing the reference signal, broadcast channel, and / or synchronization signal. AL may be signaled in unused DCI bits carried on the legacy PDCCH (eg, if it may be configured) or on the ePDCCH.

[0335] Variable number N per eCCE eREGs may be used to maintain a similar effective coding rate. Since the ePDCCH decoding candidates may be based on the eCCE level, the available number of REs for an eCCE may vary depending on the different numbers of N eREGs can be mapped. eREGs can be mapped to each eCCE, the effective coding rate can be lowered so that the channel coding gain increases as a result. eREGsmay be mapped when the puncturing of ePDCCH REs reduces the available number of REs per eCCE in a particular subframe. eREGs The variable number of may be defined as described herein. For example, N eREGs may be configured by the eNB and signaled to the WTRU or UE via a broadcast channel and / or higher layer signaling. eREGs can be configured independently for each subframe with a duty cycle. For example, duty cycles of 10 ms and 40 ms can also be used. eREGs are defined, and one of them may be selected according to the CSI-RS and ZP-CSI-RS configuration.

[0336]

number

[0337] and

[0338]

number

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

[0340]

number

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

[0342]

number

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

[0344] Since the number of REs for an eREG may be variable, the number of REs for an eCCE may also be variable. The eCCE may be defined differently according to 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 In one embodiment, N = 2 may be used. eREGs may be configurable by the eNB via broadcasting (MIB or SIB-x) and / or higher layer signaling.

[0345] In another embodiment, N eREGs may vary from subframe to subframe as described herein. eREGs The value may be changed if the subframe contains CSI-RS and / or zero-power CSI-RS. For example, N eREGs = 4 is used in subframes that do not contain CSI-RS and / or zero-power CSI-RS, and N eREGs N = 6 may be used in subframes containing CSI-RS and / or zero-power CSI-RS. eREGs The value is N when the reference signal overhead is higher. eREGs For example, if the reference signal overhead can be less than 15% of the PDSCH region in a subframe, then N eREGs = 4, where the reference signal overhead can be between 15% and 20% of the PDSCH region within a subframe. eREGs = 5, where the reference signal overhead can be between 20% and 30% of the PDSCH region within a subframe. eREGs = 6, when the reference signal overhead can exceed 30% of the PDSCH region in a subframe, when the reference signal overhead can be defined as "number of PDSCH REs / number of reference signals", and similar cases. eREGs= 5. In one embodiment, eREG and eCCE may be the same in a particular ePDCCH transmission mode, such as centralized transmission of ePDCCH.

[0346] N eREGs Another category can be considered where the number of (i) may be fixed for each eCCE, e.g., 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 on these REs for other purposes such as reference signals, PDCCH, and / or PSS / SSS, and applying special precoding or mutually orthogonal patterns to both ePDCCH and non-ePDCCH. At the receiver side, after de-precoding by the WTRU or UE, the ePDCCHs are separated and a similar effective coding rate for a given DCI payload can be maintained.

[0347] N eREGs Assuming that the number of (i) varies per eCCE, the jth eREG (e.g., K RES Instead of fixing the number of available REs for (i,j)) at the receiver side, e.g., for a portion of the eREGs as described above (e.g., after de-precoding by the WTRU or UE), the ePDCCH may be separated and a similar effective code rate for the DCI payload may be maintained.

[0348]

number

[0349] can be adapted so that can be maintained for each CCE.

[0350] Additionally, the eCCE definition may differ depending on the ePDCCH search space. In such an embodiment, eCCEs may be defined for the WTRU- or UE-specific search space and the common search space, respectively, in the following manner. For example, the eCCE definition for the WTRU- or UE-specific search space may satisfy one or more of the following characteristics: 16 eREGs may be defined per PRB pair, regardless of CP length and subframe type. 4 or 8 eREGs may be grouped to form an eCCE depending on the CP length and subframe type. 4 eREGs may be grouped to form an eCCE for a normal CP with normal subframes and / or a normal CP with special subframe configuration {3, 4, 8}. In one embodiment, 8 eREGs may be grouped to form an eCCE for a normal CP with special subframe configuration {2, 6, 7, 9}, an extended CP with normal subframes, and / or an extended CP with special subframe configuration {1, 2, 3, 5, 6}. Furthermore, four or eight 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 the WTRU or UE can monitor the PDCCH common search space in a subframe, the number of eREGs per eCCE for a WTRU- or UE-specific search space may be eight, but if the ePDCCH common search space may be monitored together with the ePDCCH WTRU- or UE-specific search space, the number of eREGs per eCCE for a WTRU- or UE-specific search space may be four.

[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 per PRB pair, regardless of CP length and subframe type. Four or eight eREGs may also be grouped together as a WTRU or UE-specific search space. Furthermore, the four or eight eREGs may be grouped together depending on the number of available REs (e.g., n ePDCCH) to form eCCEs. In such an embodiment, the number of available REs may be counted in each subframe in a PRB pair that does not include a PSS / SSS and / or PBCH. In addition, n ePDCCH If is less than a predefined threshold (e.g., 104), the eight eREGs may be grouped to form an eCCE; otherwise, four eREGs may be used and / or grouped together.

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

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

[0354] For the eCCE-eREG mapping in the shared PRB, at least one of the following methods may be used (e.g., contiguous allocation (mapping-1), interleaved allocation (mapping-2), hybrid allocation (mapping-3), and / or the like). In contiguous allocation (mapping-1), N eREGs Consecutive eREGs are aggregated for an eCCE definition, and therefore the eCCE number is eCCE#n=eREGs#{n·N eREGs ,...,(n+1)·N eREGs -1). For example, N eREGs = 4 and n = 0, then eCCE#0 = eREGs#{0, 1, 2, 3}. In one such embodiment, the total number of eCCEs (M eCCE )teeth,

[0355]

number

[0356] Figure 21 illustrates such an example (eg, Figure 21 illustrates an example embodiment of eCCE-eREG mapping with contiguous allocation).

[0357] In interleaved allocation (e.g., mapping-2), N eREGs The interleaved eREGs are aggregated for the eCCE definition, and the eCCE number is therefore eCCE#n=eREGs#{π(n·NeREGs) ,...,π((n+1)·N eREGs -1)}, and π(·) ranges from 0 to M eCCE The interleaved sequence π(·) can represent an interleaved sequence up to N eREGs can be generated by N MeCCE block interleavers. eREGs =4 and M eCCE = 9, a 4x9 block interleaver may be defined as shown in Figure 22 (e.g., Figure 22 shows an example of a block interleaver). In a block interleaver, an interleaved sequence may be generated by writing the sequence row first and reading it 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] The interleaved sequence π(·) can be expressed as tot The permutation sequence may be generated by a random sequence of , which may be predefined and known by both the WTRU or UE and the eNB. Column permutation may be used, for example, to further randomize the permutation sequence.

[0360] In hybrid allocation (mapping-3), a subset of consecutive sequences is reserved for centralized transmission, and 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 (e.g., Figure 23 shows hybrid allocation by using a block interleaver), and eCCEs #{4, 5, 6, 7} can be used for centralized transmission, and other eCCEs can be used for distributed allocation. To generate centralized eCCEs, N eREGs From this operation, N consecutive eCCEs can be used. eREGs N consecutive distributed allocation-based eCCEs are eREGs To generate both centralized and distributed eCCEs, the eNB eCCE Define distributed eCCEs and N for centralized eCCEs. eREGs Contiguous or closed eCCEs can be reserved. Column 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 illustrates an example embodiment of the coexistence of centralized and distributed eCCEs.

[0361] For eCCE-eREG mapping in another PRB, eREG may be defined independently for centralized transmission 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 contiguous allocation (e.g., mapping-1) being used for LeREG and / or interleaved allocation (e.g., mapping-2) being 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: eCCE allocation (e.g., mapping-1, mapping-2, or mapping-3) is predefined, the mapping method may vary by subframe index and / or SFN, the mapping method may be configurable by higher layer signaling, the mapping method may vary by ePDCCH PRB pair and / or the like. According to one exemplary embodiment, N eRB may be available for ePDCCH transmission, N eRB A subset of N may use mapping-1, and other ePDCCH PRB pairs (e.g., the rest of the ePDCCH PRB pairs) may use mapping-2. eRB can be defined separately for each mapping method.

[0363] If 16 eREGs are available per PRB pair and one eCCE can be defined by grouping four eREGs, four eCCEs can be defined per 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 among the 16 eREGs can be grouped to form a centralized eCCE. The eCCE-eREG mapping rule can be the same for each PRB pair configured as an ePDCCH resource. Four consecutive eREGs in a PRB pair with the same starting point can be used regardless of the cell. For example, the eREG-eCCE mapping rule can be, for each cell, 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 in a PRB pair with different starting points can be used. The starting point of eREG may be configured via higher layer signaling or defined as a function of at least one of system parameters such as physical cell ID and subframe / SFN number. In the following example, the offset may be configured via higher layer signaling or defined as a function of at least one of system parameters. In one example, eCCE(n) = {eREG((k+i+offset) mod 16), i = 0, 1, 2, 3}, eCCE(n+1) = {eREG((k+4+i+offset) mod 16), i = 0, 1, 2, 3}, eCCE(n+2) = {eREG((k+8+i+offset) mod 16), i = 0, 1, 2, 3}, and / or eCCE(n+3) = {eREG((k+12+i+offset) mod 16), i = 0, 1, 2, 3}.

[0364] Additionally, in one embodiment, among the 16 eREGs, four mutually exclusive eREGs may be grouped to form an eCCE, where four eCCEs are defined for each PRB pair, and each eCCE may include four mutually exclusive eREGs. The four mutually exclusive eREGs may be selected by using one or more embodiments described herein to form an eCCE. For example, interleaved mapping may 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 mapping 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 mapping may be used for eREG-eCCE mapping based on a random interleaver. The interleaved sequence may be predefined or configured via higher layer signaling. If the interleaved sequences for each eCCE in a 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}, where 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))}. The interleaved sequence may be defined as a function of at least one of the system parameters, including the physical cell ID, the subframe, and / or the SFN number.

[0365] Antenna port mapping may also be implemented and / or used. For example, antenna ports {107, 108, 109, 110} may be used interchangeably with antenna ports {7, 8, 9, 10} because antenna ports {7, 8, 9, 10} or a subset thereof may be used for ePDCCH transmission and may be at 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 illustrates an example embodiment of antenna port mapping for eREG / eCCE. As shown in Figure 25, eREG / eCCE may be mapped onto antenna ports. Figure 25 also illustrates that the number of available antenna ports may vary depending on the configuration.

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

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

[0368] A WTRU or UE may assume that eREGs / eCCEs associated with the WTRU or UE in a "precoding resource granularity (PRG)" may be transmitted on the same antenna port. For example, if the 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 antenna ports within the PRG. The PRG size may vary depending on the system bandwidth. Table 12 shows an example embodiment of PRG sizes for ePDCCH.

[0369] [Table 14]

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

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

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

[0373] In one embodiment, the WTRU or UE may assume that a single antenna port configured via higher layer signaling may be associated with each eREG / eCCE in centralized transmission. A predefined one-to-one mapping between eREG / eCCEs and antenna ports may 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, modulation symbols of DCI after channel coding may be mapped onto ePDCCH REs. Because ePDCCH REs may be located within RE locations, a mapping rule may be defined in terms of a coding chain. In a coding chain aspect, the RE mapping rule may include puncturing and / or rate matching as disclosed herein. The puncturing 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 the DCI payload as input, where the channel encoder may be a channel code such as a turbo code, a convolutional code, or a Reed-Muller code. The coded bits may include a CRC attachment, e.g., 16 bits masked with the RNTI. The modulation symbols (x1, .., x M ) may be the output of the mapper. The coded bits may be modulated into modulation schemes such as BPSK, QPSK, 16QAM, 64QAM, and the like. According to the modulation scheme, the modulation symbol sequence M may be less than or equal to N. In the RE mapping, the modulation symbol x 1、 ..., x M are mapped to ePDCCH REs, e.g., frequency first or time first, where puncturing may imply or stipulate that if an RE in the ePDCCH may be occupied for another signal, no modulation symbols for that RE are transmitted. For example, x k (k≦M) are mapped onto a specific ePDCCH RE according to a mapping rule, and if the ePDCCH RE can be occupied for another purpose, then x k is not sent, and the next mapping is k+1The rate matching can start from x in the same situation. k As an example, if there are 6 modulation symbols {x1, x2, x3, x4, x5, x6} to transmit and the ePDCCH REs for x2 and x4 may be occupied for other purposes, then {x1, x3, x5, x6} may be transmitted if a puncturing scheme may be used, and {x1, x2, x3, x4} may be transmitted if rate matching may be used.

[0376] Because the puncturing scheme may lose systematic bits when convolutional and / or turbo codes may be used, the decoding performance may be worse than the rate matching scheme in one embodiment when the coding rate may be high. Puncturing can be robust when the occupied RE information cannot be synchronized between the eNB and the WTRU or UE. Channel decoding may fail when the occupied RE information for the rate matching scheme is not synchronized between the eNB and the WTRU or UE. Puncturing and rate matching rules based on the purpose of the occupied RE may be implemented and / or used.

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

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

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

[0380] Rate matching and puncturing rules may also be defined by semi-static and dynamic signals. In an example of rate matching, an RE may be occupied by fixed, cell-specific signals including CRS, PSS / SSS, and / or PBCH. In puncturing, an RE may be occupied by semi-static or dynamic configurations including PDCCH, CSI-RS, DM-RS, and / or PRS. In an example of rate matching, an RE may be occupied by semi-static or dynamic configurations including PDCCH, CSI-RS, DM-RS, and / or PRS. In puncturing, an 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, the rate mapping and puncturing rules may be defined differently when the search space can be a WTRU- or UE-specific search space or a common search space (e.g., different rate-matching and / or puncturing rules may apply for a WTRU- or UE-specific search space than 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 collide 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 may be applicable: By way of example (e.g., with respect to REs configured as ePDCCH common search space resources), REs located in CRS positions may be rate-matched here and there. In one such embodiment, the number of CRS ports may be fixed to 4 regardless of the number of CRS ports detected on the PBCH. As such, the WTRU or UE may assume that REs located in CRS ports 0-3 may be rate-matched here and there when decoding the ePDCCH common search space. Additionally, in such an embodiment, the WTRU or UE may follow and / or use the number of CRS ports detected on the PBCH for rate-matching of REs located in CRS ports.

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

[0384] In one example embodiment, for 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 rate-match here and there for the REs located at the location of the PDCCH, otherwise the WTRU or UE can rate-match here and there for the REs located in the OFDM symbols below the ePDCCH common search space starting 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 such that multiple blind decoding attempts are used per subframe. Candidates for blind decoding attempts from the perspective of a WTRU or UE may hereinafter be referred to as a 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 may carry DCI related to a group of UEs and / or UEs in a cell, such as broadcasting / multicasting, paging, group power control, etc. The WTRU- or UE-specific search space may carry DCI for uplink and / or downlink unicast traffic.

[0386] From the perspective of a WTRU or UE, there may be at least two search spaces, and locations for the search spaces may be defined using at least one of the following configurations: In one configuration (e.g., configuration 1), the USS and CSS are both provided or used in the legacy PDCCH, and the WTRU or UE may monitor the USS and CSS. In such a configuration, the WTRU or UE may monitor the 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), the USS and CSS are both provided or used in the ePDCCH, and the WTRU or UE may monitor the USS and CSS (e.g., the WTRU or UE may monitor the USS and / or CSS in the ePDCCH region). In yet another configuration (e.g., configuration 3), a USS in the legacy PDCCH may be provided or used, and a CSS in the PDCCH may be provided or used (e.g., a WTRU or UE may monitor a CSS in the legacy PDCCH region and / or a USS in the ePDCCH region). Additionally, in one configuration (e.g., configuration 4), a USS in the ePDCCH may be provided or used, and a CSS in the legacy PDCCH may be provided or used; for example, a WTRU or UE may monitor a CSS in the legacy PDCCH region and a USS in the ePDCCH region. Additionally (e.g., in configuration 4), the CSS may be shared with legacy UEs. In this case, CCEs 0 to 15 may be used as the CSS in the legacy PDCCH region. In configuration 4, the CSS may be defined differently. For example, CCEs 16 to 31 in the legacy PDCCH may be used as the CSS for a WTRU or UE configured with the ePDCCH for USS. In another example configuration (eg, configuration 5), a USS in the ePDCCH is provided or used, and the CSS may be split between the legacy PDCCH and the ePDCCH.According to an additional configuration (e.g., configuration 6), the USS is split into a legacy PDCCH and an ePDCCH, and a CSS in the ePDCCH may be provided or used. Also, in one configuration (e.g., configuration 7), both the USS and the CSS may be split into a legacy PDCCH and an ePDCCH. In configuration 8, the USS is split into a legacy PDCCH and an ePDCCH, and a CSS in the legacy PDCCH may be provided or used.

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

[0388] The eCCE aggregation level is defined as the same as the 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 eCCEs may be variable, unlike CCEs in the legacy PDCCH, and the coding rate for ePDCCH with aggregation levels may vary, 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 provide finer ePDCCH link adaptation as shown in Table 13. For WTRU or UE specific search spaces, aggregation levels {3, 5, 6, 7} may be added, and {6} may be added, for example, for a common search space.

[0390] [Table 15]

[0391] Although the number of aggregation levels can be increased, the number of blind decoding attempts can be kept as before to avoid increasing the complexity of the WTRU or UE receiver. To preserve the number of blind decoding attempts, a subset of the aggregation levels can be monitored in a subframe.

[0392] [Table 16]

[0393] Additionally, the WTRU or UE may monitor a subset of aggregation levels according to the subset of ePDCCH candidates shown in Table 14. The subset for ePDCCH monitoring may be configured based on or according to at least one of the following: the subset of ePDCCH aggregation levels may be configured by broadcasting and / or higher layer signaling, the reference signal overhead in the ePDCCH resources may implicitly configure the subset, the subset may be configured differently according to the ePDCCH transmission mode (e.g., mode-1 and mode-2), the subset may be configured differently depending on the ePDCCH PRB number, and / or similar configuration may occur.

[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 may be used more frequently for DCI formats 0 / 1A, a larger number of ePDCCH candidates may be used for aggregation level 1 compared to aggregation level 2. A larger number of ePDCCH candidates may be used for DCI format 2C compared to aggregation level 1.

[0395] Table 14-1 shows an example of an ePDCCH candidate set depending on the DCI format, which may differ when different DCI formats may be used, in which the number of ePDCCH candidates according to the aggregation level may differ.

[0396] [Table 17]

[0397] A WTRU or UE may attempt to decode 8 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 may attempt to decode 4 ePDCCH candidates.

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

[0399] The number of ePDCCH candidates according to aggregation level {1, 2, 4, 8} may be configured via broadcasting and / or higher layer signaling. In one cell, the ePDCCH candidates may be configured as {6, 6, 2, 2} (e.g., the same as for legacy PDCCH), while in another cell, for example, {2, 10, 2, 2} may be configured as ePDCCH candidates. The ePDCCH candidates for an aggregation level may 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 may be defined by indication bits, for example, as shown in Table 14-2.

[0400] [Table 18]

[0401] In some embodiments, one or more of the sets for ePDCCH candidates may have the same number of ePDCCH candidates as the legacy PDCCH, e.g., {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 have no ePDCCH candidates for the common search space. In this case, the WTRU or UE may monitor the PDCCH candidates as the common search space. One or more of these sets may include a subset of aggregation levels that may have no candidates. For example, {8, 8, 0, 0} may be used such 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 the ePDCCH in a common search space and / or a WTRU- or UE-specific search space. In one embodiment, the ePDCCH candidates that a WTRU or UE can monitor in a subframe may be defined according to the ePDCCH transmission type.

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

[0404]

number

[0405] teeth,

[0406]

number

[0407] where i=0,...,L-1,

[0408]

number

[0409] and

[0410]

number

[0411] is.

[0412]

number

[0413] may represent the number of ePDCCH candidates for aggregation level L in ePDCCH resource set p. Y may be a hash function for ePDCCH resource set p. p,k is Y p,k =(A Y k-1 ) mod D, where Y p,-1 =n RNTI ≠0, A=39827, D=65537, and

[0414]

number

[0415] is.

[0416] In addition, the ePDCCH candidates for the centralized ePDCCH resource set are adjusted by an offset value (K offset ) The same WTRU- or UE-specific search space formula may be used for both centralized and distributed ePDCCH. In this embodiment, for example, the WTRU- or UE-specific search space for the ePDCCH resource set p configured in the centralized ePDCCH

[0417]

number

[0418] teeth,

[0419]

number

[0420] K for ePDCCH resource set p can be defined as offset,pK may be configured via higher layer signaling in a WTRU or UE specific manner. offset,p is 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 may be defined as a function of at least one parameter of

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

[0422]

number

[0423] where the offset (K offset,p ) can be defined as a function of the number of ePDCCH candidates (m'). offset,p An example embodiment of the definition of may be as follows: In such example embodiments (eg, example formulas), m' and m may be used interchangeably.

[0424] According to one exemplary embodiment:

[0425]

number

[0426] may 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] where N eCCE,k,p and

[0429]

number

[0430] may be ePDCCH resource specific.

[0431] In another example embodiment,

[0432]

number

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

[0434] In another example, the offset (e.g., according to the ePDCCH candidate number and aggregation level) may be calculated as: offset,p ) can be defined as a function of the ePDCCH candidate number.

[0435]

number

[0436] In this embodiment, the offset can be expressed as:

[0437]

number

[0438] In addition, an ePDCCH resource set specific offset value Δ offset,p is the Δ offset,p=0 =0 and Δ for the second ePDCCH resource set offset,p=1 =λ, where λ is a predefined positive integer number (e.g., λ=3), and Δ offset,p is configured via higher layer signaling, and Δ offset,p 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 may be configured as a function of the subframe number and / or the aggregation level.

[0439] According to additional examples,

[0440]

number

[0441] can be used (e.g., can be defined in terms of offsets), where Φ offset is the offset value for cross-carrier scheduling, and n CI may be the carrier indicator field value. offset may have different numbers according to the ePDCCH resource set, in which case Φ offset is Φ offset,p Furthermore,

[0442]

number

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

[0444]

number

[0445] can be defined as, where:

[0446]

number

[0447] may be the number of ePDCCH candidates for aggregation level L in ePDCCH resource set p.

[0448] In another example,

[0449]

number

[0450] can be used, where Φ offset is the offset value for cross-carrier scheduling, and Δoffset,p is the offset for EPDCCH resource set p, and n CI can be the carrier indicator field value, or

[0451]

number

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

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

[0454] [Table 19]

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

[0456]

number

[0457] teeth,

[0458]

number

[0459] where i=0,...,L-1, m'=m+M (L) n CI , and m=0,...,M (L) −1, and τ may be defined as a fixed value in a predefined manner or may be configured via higher layer signaling in a WTRU or UE specific manner, and / or τ may be defined as a function of the WTRU or UE ID. For example, τ= nRNTI is.

[0460] The search space may include multiple ePDCCH resource sets. The multiple ePDCCH resource sets may have a number of PRB pairs that can be used, and / or this number may be fixed regardless of the system bandwidth, cell ID, and / or subframe number, or may be variable depending on the system bandwidth, cell ID, and / or subframe number. The same number of eCCEs may be available on the ePDCCH resource sets. The number of eCCEs available on the ePDCCH resource sets may be fixed regardless of the system bandwidth, cell ID, and / or subframe number. The number of eCCEs available on the ePDCCH resource sets may be variable depending on the system bandwidth, cell ID, and / or subframe number. The number of eCCEs available on the ePDCCH resource sets 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 (e.g., 2 or 4 eCCEs per PRB pair may be used with twice the number of PRB pairs). Additionally, the number of eCCEs available in an ePDCCH resource set may vary depending on the configuration.

[0461] In another embodiment, the available number of 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 system configuration including CP length, subframe type, duplex mode (TDD or FDD), and / or carrier type (e.g., legacy carrier or other carrier type). est Given that the number and CP length may be used for the ePDCCH resource set, a larger number of available eCCEs may be defined in a non-legacy carrier type compared to that of a legacy carrier, and the non-legacy carrier type may implicitly indicate that the carrier does not have legacy downlink control channels and CRSs in the downlink subframe (e.g., PDCCH, PHICH, and PCFICH).

[0462] A subset of ePDCCH resource sets among multiple ePDCCH resource sets or configured ePDCCH resource sets may be used for a WTRU or UE specific search space. set If = 3 ePDCCH resource sets may be defined, then two ePDCCH resource sets (e.g., sets 1 and 2) may be used as ePDCCH resources for a particular WTRU or UE. The multiple PDCCH resource sets may have at least one of the following characteristics:

[0463] According to one exemplary embodiment, K setePDCCH resource sets are defined, and each ePDCCH resource set may include the same number of eCCEs (e.g., 16 eCCEs). The number of eCCEs may be fixed or variable depending on system parameters. The eCCE index may 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), and each ePDCCH resource set may include 16 eCCEs, the eCCE indexes may be defined as (eCCE#0, ..., eCCE#15) for the first ePDCCH resource set, and (eCCE#16, ..., eCCE#31) and (eCCE#32, ..., eCCE#47) for the second and third ePDCCH resource sets, respectively. eCCE is K set ·K eCCE and K eCCE represents the number of eCCEs in the ePDCCH resource set, and N eCCE =K set ·K eCCE The total number of eCCEs in subframe k can be expressed as N eCCE,k In one embodiment, a WTRU or UE specific search space

[0464]

number

[0465] teeth,

[0466]

number

[0467] 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 ) mod D, where Y -1 =n RNTI ≠0, A=39827, D=65537, and

[0468]

number

[0469] It can be said that:

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

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

[0472] [Table 20]

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

[0474]

number

[0475] teeth,

[0476]

number

[0477] or

[0478]

number

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

[0480]

number

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

[0482] In addition, Y p,k is Y p,k =(A Y p,k-1 +Δ offset,p ) mod D, where Δ offset,p may be an offset to the ePDCCH resource set p. In one such embodiment, Δ offset,p can be defined as at least one of the following: a value configured by higher layers, a predefined number that can be used for ePDCCH resource set specific offset, e.g., DELTA offset,p=0 =0 and DELTA offset,p=1 = λ, where λ is an offset, which can be a predefined number (e.g., 3) and / or can be randomly generated (e.g., Δ offset,p=0 =0 and / or Δ offset,p=1 =λ, where λ is an offset that may be defined as a function of one or more of the 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 exemplary embodiment, Y p,k is Y p,k =(A p Y p,k-1 +Δ offset,p ) mod D, where Δ offset,pmay be an ePDCCH resource set specific offset.

[0484] A WTRU or UE specific search space may be defined over multiple ePDCCH resource sets, and the location of the ePDCCH candidates for blind detection may be defined as a function of the ePDCCH resource set number and the eCCE number.

[0485] In addition, an eCCE index may be defined for one or more ePDCCH resource sets, and the associated ePDCCH resource sets may differ depending on the ePDCCH transmission type and / or the eCCE aggregation level. In this case, one or more of the following may apply: 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, may be used and / or the ePDCCH resource set may be configured for 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, for example, 8 or more, may be used and / or the ePDCCH resource set may be configured for centralized transmission; One or more subsets of the ePDCCH resource sets may be indicated from an indication channel (e.g., enhanced PCFICH) in each subframe.

[0486] For multiple ePDCCH resource sets, each ePDCCH resource set may be independently configured for either centralized or distributed ePDCCH transmission. When multiple ePDCCH resource sets may 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 may be defined differently for centralized and distributed ePDCCH resource sets, different hash functions may be used for centralized and distributed ePDCCH resource sets, and / or K set ePDCCH resource sets are defined, each of which may have a different number of eCCEs (eg, 16 eCCEs in the primary set and 32 eCCEs in the secondary set).

[0487] If the ePDCCH candidates may be defined differently for centralized and distributed ePDCCH resource sets, one or more of the following may be applied and / or used: k) is used for the distributed ePDCCH resource set, and the offset value K offset may be used for the centralized ePDCCH resource set, and an ePDCCH resource set-dependent hash function may be used for the distributed ePDCCH resource set. If different hash functions may be used for the centralized and distributed ePDCCH resource sets, a legacy hash function may be used for the distributed ePDCCH resource set, but a separate hash function may be defined for the centralized ePDCCH resource set.

[0488] Embodiments of antenna port mapping based on a search space may also be provided and / or used as described herein. For example, the same or similar ePDCCH candidates in a WTRU- or UE-specific search space may have different antenna ports and / or scrambling IDs, while a common search space may have the same antenna port and / or scrambling ID. In such embodiments, if a WTRU- or UE-specific search space may be defined as {eCCE#n,...,eCCE#n+k}, the operation of a WTRU or UE monitoring the ePDCCH may include one or more of the following: The antenna ports for the eCCEs in the WTRU- or UE-specific search space may be configured in a WTRU- or UE-specific manner. For example, a WTRU or UE may demodulate eCCE#n on antenna port 7, while another WTRU or UE may demodulate eCCE#n on antenna port 8. The antenna configuration may be signaled to the WTRU or UE via higher layer signaling or may be implicitly derived from the RNTI. The antenna ports for eCCEs in a WTRU- or UE-specific search space may be blindly decoded within the WTRU- or UE-specific search space. For example, the WTRU- or UE-specific search space may include eCCE#n via antenna port 7 and eCCE#n via antenna port 9. The WTRU or UE may also demodulate (e.g., iteratively demodulate) the same resource (eCCE#n) via antenna port 7 and antenna port 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 equivalently {107, 108, 109, 110} may be used. In this case, the DM-RS sequences for the antenna ports may be

[0490]

number

[0491] where the sequence initialization c init teeth,

[0492]

number

[0493] can be defined as, where:

[0494]

number

[0495] and (X ID ,n SCID ) can be used interchangeably. init With regard to the definition of , one or more of the following may be applicable: 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 may be used for the same ePDCCH resource (e.g., PRB pair) according to a WTRU or UE and / or blind decoding attempt, thereby, for example, increasing multi-user multiplexing gain. As an example, a WTRU or UE may demodulate eCCE#n with a scrambling sequence, and another WTRU or UE may demodulate eCCE#n with another scrambling sequence, where the scrambling sequence may be associated with a demodulation reference signal (e.g., antenna port). As another example, a WTRU or UE may demodulate eCCE#n with scrambling sequences A and B. Scrambling sequence candidates may be defined as follows: A scrambling sequence candidate is n SCID and / or X ID The scrambling sequence candidates are defined by {n SCID =0, n SCID= 1}, and / or the scrambling sequence candidates are defined as {(X1, n SCID =0), (X2, n SCID =0), (X1, n SCID =1), (X2, n SCID =1)}, where X1 and X2 may be different numbers defined within the range of 0 to the cell ID number.

[0497] A single scrambling sequence is used with cell-specific parameters X ID is used for a fixed number n SCID X ID n may be defined as a physical cell ID or configured by higher layer signaling. SCID can be fixed as 0 or 1.

[0498] When multiple ePDCCH resource sets are defined, a scrambling sequence may be used for each ePDCCH resource set or across ePDCCH resource sets. For example, a scrambling sequence may be defined for each ePDCCH resource set. In addition, X ID may be defined for each ePDCCH resource set so that multiple scrambling sequences are used without dynamic indication. In such an embodiment, if the ePDCCH resource sets are configurable, then for each ePDCCH resource set, an associated X ID In this case, n SCID can be fixed as 0 or 1. Two X ID is configured via higher layer signaling, and each ePDCCH resource set is assigned to X according to the configuration. ID You can use one of the fixed predefined X ID may be used for ePDCCH candidates in the common search space such that the WTRU or UE demodulates the ePDCCH candidates in the common search space. ID is used for ePDCCH candidates within a WTRU or UE specific search space, and XID may vary depending on the ePDCCH resource set or may be the same for the ePDCCH resource set. ID may 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: The WTRU or UE may use the same X as used in the associated ePDCCH for PDSCH demodulation. ID and / or X used in the associated ePDCCH ID Regardless of the DCI associated with the WTRU or UE, SCID X indicated by ID n SCID = 0, then X1 may be used. Otherwise, X2 may be used. The WTRU or UE may use the same X as used in the associated ePDCCH for PDSCH demodulation. ID If the PDSCH can be used, the scrambling sequence may be aligned between the PDSCH and the associated ePDCCH so that coordinated multipoint transmission (CoMP) operation is applied to the ePDCCH.

[0499] X ID The use of X may depend on the configured transmission mode for the PDSCH. For example, if the WTRU or UE may be configured for non-CoMP operation, a single X ID is used for the ePDCCH resource set, and X ID However, if the WTRU or UE can be configured for CoMP operation, X may be greater than or equal to 2. ID are used, and each of the ePDCCH resource sets is ID As such, X ID may or may not be the same for the ePDCCH resource set.

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

[0501]

number

[0502] is defined as n EPDCCH ID is configured via higher layers per ePDCCH resource set,

[0503]

number

[0504] may be a fixed number (e.g., 0, 1, or 2). For the ePDCCH common search space,

[0505]

number

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

[0507]

number

[0508] may be a fixed number (e.g., 0, 1, or 2). For example,

[0509]

number

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

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

[0512] Additionally, in one embodiment, if multiple (e.g., two) ePDCCH resource sets are configured for ePDCCH WTRU- or UE-specific search spaces and (e.g., one) ePDCCH resource set may be used for the ePDCCH common search space, one or more of the following may apply and / or be used and / or provided, e.g., sequence initialization c for the WTRU- or UE-specific search space init may be defined in a WTRU- or UE-specific manner for each ePDCCH resource set, where the ePDCCH WTRU- or UE-specific resources may not overlap with the ePDCCH common search space resources. In one such embodiment, the sequence initialization c init teeth,

[0513]

number

[0514] is defined as n EPDCCH ID is configured via higher layers per ePDCCH resource set,

[0515]

number

[0516] may be a fixed number (e.g., 0, 1, or 2).

[0517] For WTRU- or UE-specific search space resources of the ePDCCH that may fully and / or partially overlap with the ePDCCH common search space resources, sequence initialization c for the WTRU- or UE-specific search space. init may be defined the same as the ePDCCH common search space DM-RS sequence initialization. In one such embodiment, if the ePDCCH common search can use a cell-specific DM-RS sequence, then the WTRU or UE-specific DM-RS sequence for the ePDCCH resource set that overlaps the common search space can use the cell-specific DM-RS sequence. Additionally, in such an embodiment, the sequence initialization c for the WTRU or UE-specific search space init where the WTRU or UE specific search space cannot overlap with the ePDCCH common search space.

[0518]

number

[0519] is defined as, where

[0520]

number

[0521] is configured via higher layers per ePDCCH resource set,

[0522]

number

[0523] may be a fixed number (e.g., 0, 1, or 2).

[0524] Additionally, in one example embodiment, sequence initialization c for a WTRU or UE specific search space init where the WTRU or UE specific search space may overlap with the ePDCCH common search space:

[0525]

number

[0526] is defined as, where

[0527]

number

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

[0529]

number

[0530] may be a fixed number (e.g., 0, 1, or 2). For example,

[0531]

number

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

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

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

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

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

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

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

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

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

[0541]

number

[0542] and

[0543]

number

[0544] 1 illustrates an example where multiple ePDCCH candidates may be indicated for ePDCCH mode-1 and mode-2, respectively. A WTRU or UE may monitor one ePDCCH mode configured by the eNB via higher layer signaling.

[0545] [Table 21]

[0546] When cross-carrier scheduling may be activated, the PDCCH may be restricted to transmission within the PCell such that the WTRU or UE monitors the PCell when it is restricted to receiving the PDCCH. As the ePDCCH is defined, the behavior of the WTRU or UE when cross-carrier scheduling may be activated may be defined in one or more of the following ways: The legacy PDCCH and / or ePDCCH may be restricted to being transmitted on the PCell according to the PDCCH configuration. If the eNB can configure a legacy PDCCH for the WTRU or UE, the WTRU or UE may be restricted to monitoring the legacy PDCCH on the PCell. Otherwise, the WTRU or UE may monitor the ePDCCH in the PCell. The WTRU or UE may assume that the respective PDCCH may be transmitted on the PCell.

[0547] Additionally, PCells are defined independently for the legacy PDCCH and ePDCCH, such as PCell_pdcch and PCell_epdcch, where PCell_pdcch and PCell_epdcch represent the PCells for the legacy PDCCH and ePDCCH, respectively. A WTRU or UE can monitor PCell_epdcch for a set of component carriers configured for ePDCCH and PCell_pdcch for other component carriers configured for legacy PDCCH. PCell_pdcch and PCell_ePDCCH may be the same component carrier.

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

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

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

[0551] In an example manner, TBS constraints may be used as follows (e.g., according to one or more of the following):

[0552]

number

[0553] and

[0554]

number

[0555] teeth,

[0556]

number

[0557] can be defined if

[0558]

number

[0559] and

[0560]

number

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

[0562]

number

[0563] It may be assumed that a larger TBS cannot be transmitted to the WTRU or UE.

[0564]

number

[0565] and

[0566]

number

[0567] is a WTRU or UE specific time advance value (T TA ) can be defined as a function of the maximum TBS

[0568]

number

[0569] too,

[0570]

number

[0571] where Δ can be a TBS table.

[0572] In addition,

[0573]

number

[0574] is the expression

[0575]

number

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

[0577]

number

[0578] (where δ is a weighting coefficient) may be defined as a function of the time advance value in at least one of

[0579] moreover

[0580]

number

[0581] is the expression

[0582]

number

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

[0584]

number

[0585] (where δ is a weighting coefficient) may be defined as a function of the time advance value in at least one of

[0586] In an embodiment,

[0587]

number

[0588] is the expression

[0589]

number

[0590] or

[0591]

number

[0592] (However, N TBS represents the maximum TBS size without restrictions, and ε is a weighting factor) and / or

[0593]

number

[0594] or

[0595]

number

[0596] may be defined as a function of the time advance value in at least one of

[0597] The weighting factors γ, δ, ε that may be used as shown above may have the following properties: The weighting factors may be changed according to the class / category of the WTRU or UE and / or the weighting factors may be different depending on the transmission mode. In addition, the maximum TBS

[0598]

number

[0599] is T TAand may be defined as a function of the class / category of the WTRU or UE, e.g., for a WTRU or UE category-1, no TBS restriction may be used regardless of the time advance value.

[0600] In another example method, H-ARQ timing may be implemented (e.g., to allow for additional decoding processing time). In H-ARQ operation, a WTRU or UE may be required to transmit 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 may be 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. Additionally, in such an embodiment, the WTRU or UE's behavior may be defined as follows (e.g., if the WTRU or UE may have received an ePDCCH and corresponding PDSCH in subframe n): The WTRU or UE may transmit 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. Additionally, the variable l may be set to a positive integer greater than 4 if multiple component carriers may be activated. The variable l may also be configured via higher layer signaling to a number in a set of candidates, e.g., {4, 6, 8, 10}, if multiple component carriers may be activated, or set to k if a single component carrier may be activated.

[0601] In a further example method, the ePDCCH and corresponding PDSCH may be transmitted in different subframes such that the WTRU or UE monitors the ePDCCH in subframe n i and expects to receive the corresponding PDSCH in subframe n In this case, the WTRU or UE behavior in response to a HARQ-ACK transmission may include one or more of the following:

[0602] For example, the variable i may be either '0' or a positive integer and may be configured by higher layer signaling. In one embodiment, the variable i may be set to '1' in an FDD system. The WTRU or UE may transmit the 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] The ePDCCH is a time advance (T TA ) can be greater than the threshold (α), it can be transmitted in subframe ni. TA >α, the WTRU or UE may expect to receive the corresponding PDSCH in subframe n if the WTRU or UE can receive the ePDCCH in subframe n i. TA For ≦α, the WTRU or UE may receive (eg, may expect to receive) the ePDCCH and the corresponding PDSCH in the same subframe (eg, α=0.17 ms).

[0604] In addition, the ePDCCH is configured such that the number of available downlink PRBs (e.g., associated with the system bandwidth) is N PRB If it is acceptable to have a larger number of subframes, N i can be transmitted in the subframe. PRB is a threshold value, and in one exemplary embodiment, N PRB = 50. The ePDCCH may further be transmitted in subframes n i for Category 5 UEs.

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

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

[0607] [Table 22]

[0608] In one embodiment, the TBS restriction may apply to subframes with k, which may be less than or equal to a value K, which may be predefined by higher layer signaling or configurable. As an example, if K may be equal to 4, the TBS restriction may apply to subframes 0 and 5 in UL-DL configuration 0 of Table 16, which may apply to subframe 4 in UL-DL configuration 1. In another example, if K may be equal to 5, the TBS restriction may apply to one or more of the following subframes: subframe {0, 5} in configuration 0, subframe {4, 9} in configuration 1, subframe {3, 8} in configuration 2, subframe {0} in configuration 3, subframe {8, 9} in configuration 4, subframe {7, 8} in configuration 5, and / or subframe {9} in configuration 6.

[0609] According to an additional embodiment, the TBS restriction is such that the HARQ-ACK timing is greater than K and T TA>α. Furthermore, from the perspective of the WTRU or UE's PDSCH decoding procedure, the WTRU or UE may assume that the maximum TBS restriction cannot be applied if HARQ-ACK timing k may be greater than K (e.g., 4) in a subframe. As such, different WTRU or UE behaviors may be defined. For example, if the WTRU or UE is able to receive a TBS within the restricted TBS in a subframe where HARQ-ACK timing k may be less than or equal to K, the WTRU or UE may assume that such reception is in error and may report a DTX or NACK in subframe n+k. If the WTRU or UE is able to receive a TBS within the restricted TBS in a subframe where HARQ-ACK timing k may be greater than K, the WTRU or UE may start decoding the PDSCH and report a HARQ-ACK in subframe n+k. For TDD and FDD, the TBS restriction may be applied in a downlink subframe where the WTRU or UE may report a HARQ-ACK 4 ms after receiving the PDSCH in that subframe.

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

[0611] The 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 dropping condition may be further restricted by at least one of the following: TBS for the PDSCH in subframe n is greater than a predefined threshold, using subband CQI and / or rank in aperiodic CSI feedback mode, time advance T TA is greater than a predefined threshold, the CSI-RS associated with the aperiodic CSI feedback is transmitted in the same subframe, and the system bandwidth N PRB is greater than a predefined threshold (e.g., 50), and / or similar conditions.

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

[0613] Additionally, if the CSI request field in DCI formats 0 and 4 can trigger aperiodic CSI reporting in subframe n, the WTRU or UE can feed back CSI in subframe n+4 in an FDD system. In one embodiment, the WTRU or UE can operate if the WTRU or UE is capable of receiving a legacy PDCCH.

[0614] According to an example embodiment, if a WTRU or UE can receive ePDCCH for aperiodic CSI reporting in a multi-carrier system, the WTRU or UE's operations may include one or more of the following: The WTRU or UE may report CSI feedback in subframe n+j, where j is set to 4 if a single component carrier may be activated, j is set to 5 regardless of the number of configured component carriers (cells), j is configured by higher layers and j is used if multiple component carriers may be configured, j is set to 4 for the PCell and j is set to 5 for the SCell, and the reporting times for the PCell and SCell may be separated in the time domain, and / or j is a time advance (T TA ), aperiodic reporting triggering a bit that can indicate reporting CSI for multiple component carriers, and / or when the configured PUSCH reporting mode can be based on subband precoding matrix indicator (PMI) reporting.

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

[0616] Uplink control channel allocation via ePDCCH may be further described herein. For example, PUCCH resource mapping to a single DL carrier may be performed. In one such embodiment, PUCCH resources corresponding to DL assignment messages received on ePDCCH may be configured as a function of RRC signaling, which may be indicated to one or more WTRUs or UEs.

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

[0618] In another embodiment, the assigned ePDCCH resources may correspond to a predetermined or configured set of PUCCH resources. A WTRU or UE that receives an assignment of ePDCCH resources for decoding DL control information may obtain the corresponding PUCCH resource or a set of allowable PUCCH resources as a function of a predetermined mapping relationship or table. For example, the WTRU or UE may transmit the PUCCH resource on the assigned single PUCCH resource, or if multiple PUCCH resources may be configured, assigned, or indicated, it may transmit the PUCCH on a resource selected from the set, and the determination of the specific PUCCH resource may be subject to at least one second decision parameter, such as one or more values ​​(e.g., a value associated with the antenna port number of the DMRS for MU-MIMO) that may be derived as a function of a transmission configuration, such as a signaled value portion of the DCI (e.g., an ARI in the TPC field in Release 10) or a DL assignment message mapping to ePDCCH resources. For a small or moderately large number of WTRUs or UEs decoding the ePDCCH, explicit configuration of the corresponding PUCCH resources is under network control and may provide the flexibility to pool PUCCH resources while avoiding the introduction of protocol processing associated with legacy WTRUs decoding the PDCCH.

[0619] In addition, the PUCCH resource corresponding to the DL assignment message received on the ePDCCH may be derived through a dynamic resource allocation mechanism technique as a function of one or more transmission configurations of at least one DL signal received over the ePDCCH. CCEThe PUCCH resources that may be derived using the WTRUs or UEs may be extended by the definition of the number of CCEs for ePDCCH transmission. In such an embodiment, PUCCH resource collisions between legacy PDCCH and ePDCCH may be avoided while reusing similar PUCCH resource allocation principles, such as when legacy WTRUs or UEs and ePDCCH WTRUs or UEs may be supported on a serving cell.

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

[0621]

number

[0622] and the PUCCH resource for antenna port p1 is defined or derived as

[0623]

number

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

[0625]

number

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

[0627]

number

[0628] may be configured by a higher layer, in which case one or more of the following may apply:

[0629]

number

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

[0631]

number

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

[0633]

number

[0634] This is combined with

[0635]

number

[0636] can be configured at higher layers.

[0637]

number

[0638] resource allocation is

[0639]

number

[0640] and

[0641]

number

[0642] In this case, at least one of the following is applicable:

[0643]

number

[0644] may be configured by higher layers and / or may be used in general for PDCCH and ePDCCH (e.g., in this case

[0645]

number

[0646] may be configured by higher layers), and / or

[0647]

number

[0648] teeth,

[0649]

number

[0650] can be configured by higher layer signaling without any separate indication.

[0651] Additionally, in one embodiment, the PUCCH resources are:

[0652]

number

[0653] and

[0654]

number

[0655] n so that is configurable by higher layers eCCE For a transmission mode that can support one or multiple (e.g., up to two) antenna ports, the PUCCH resource

[0656]

number

[0657] teeth,

[0658]

number

[0659] If the WTRU or UE can be configured for MU-MIMO transmission, another decision parameter n MU For example, for antenna port p0,

[0660]

number

[0661] and for antenna port p1

[0662]

number

[0663] Like, n eCCE In one such embodiment, n MU may be determined as at least one of a parameter that may be associated with an antenna port for a UE-specific DMRS, a parameter similar to an ARI (ACK / NACK Resource Indicator) configured by higher layer signaling, and / or a pre-determined parameter.

[0664] In another example, the PUCCH resource corresponding to the DL allocation that may be received on the ePDCCH may be derived as a function of the number of CCEs, e.g., the first or predetermined CCE in an ordered sequence or an equivalent mapping unit may be obtained from decoding the DL allocation message, which may be mapped in a time and / or frequency resource grid.

[0665] Additionally, the sequence of mapping units, such as eCCEs or eREGs, that a WTRU or UE may select to dynamically derive or determine a PUCCH resource selection when decoding an ePDCCH may or may not bear a relationship to the CCE sequence and starting 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 PUCCH resources may both calculate an UL transmission configuration from a first dynamically calculated transmission configuration, such as a starting (e)CCE or equivalent, as described herein and one or more pre-configured or signaled parameters.

[0666] According to one example embodiment, PUCCH resources that may be used in connection with the PDCCH (e.g., if present) and ePDCCH may be segmented or aggregated for a WTRU assigned by the network to decode one of them. During setup, PUCCH resources may be pooled, e.g., UL RBs for decoding of the PDCCH by a legacy WTRU or UE and decoding of the ePDCCH by a WTRU or UE. In some additional embodiments (e.g., when attempting to obtain spatial multiplexing gains), separated UL resources may be selected for decoding by the WTRU of the legacy PDCCH and for those capable of ePDCCH decoding.

[0667] In the above example, when introducing an (e)CCE and / or (e)REG unit, it is not possible to imply or know that a group or unit of REs may be the same as a CCE containing nine REGs or a REG containing four REs used on a PDCCH. Additionally, the ordered sequence of mapping units corresponding to time and / or frequency resource allocations for one or more ePDCCHs may be equivalent in the described embodiments. In one embodiment, PUCCH resources, which may be configured to accommodate 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 are also described herein for PUCCH resource allocation with multiple ePDCCH resource sets. For example, if either the eCCE or eREG units in an ePDCCH set can be defined similarly to a legacy PDCCH, the corresponding PUCCH resource for the UE is

[0669]

number

[0670] and / or the PUCCH resource for antenna port p1 is derived as

[0671]

number

[0672] can be derived by, where n eCCE is the number of the first eCCE that can be used for transmitting the corresponding PDCCH within the region of the ePDCCH set configured 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] may be configured by an upper layer. In this embodiment, one or more of the following may be applicable:

[0677]

number

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

[0679]

number

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

[0681]

number

[0682] This is combined with

[0683]

number

[0684] is configured by a higher layer, and / or

[0685]

number

[0686] is configured by higher layer signaling, and the resulting resource allocation is

[0687]

number

[0688] In this last embodiment, at least one of the following is applicable:

[0689]

number

[0690] may be configured by higher layers and / or used for PDCCH and ePDCCH (e.g., in this case

[0691]

number

[0692] can be configured by higher layers),

[0693]

number

[0694] teeth,

[0695]

number

[0696] configured by higher layer signaling without further indication of

[0697]

number

[0698] is constructed independently for each set, which is

[0699]

number

[0700] It can be defined as:

[0701] Multiple

[0702]

number

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

[0704]

number

[0705] k may be defined as k = 1 k ⁢ ⁢ ⁢ nSCID ⁢ ⁢ ⁢ ⁢ k ⁢ ...

[0706] In alternative or additional embodiments,

[0707]

number

[0708] teeth,

[0709]

number

[0710] Combined with

[0711]

number

[0712] may be dynamically signaled and / or semi-statically or configured by higher layers. If the WTRU or UE may be configured for 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 can be used for the corresponding PUCCH resource in addition to n MU may be determined as at least one of a parameter associated with an antenna port for a UE-specific DMRS, a parameter similar to an ARI configured by higher layer signaling, and / or a predetermined parameter.

[0717] PUCCH resource mapping 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, the PUCCH resources corresponding to a first DL assignment message received on a first ePDCCH may be derived by the WTRU or UE as a function of a second DL assignment message received on a second DL control channel.

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

[0719] The WTRU or UE may also decode the ePDCCH in both the primary and secondary serving cells. In such an embodiment, the PUCCH resources to be used may be 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 / N, corresponding to one or more received DL assignments of these ePDCCHs. In the case of two DL serving cells, the derived PUCCH format 1 with the channel selection resource may be obtained from the DL assignment message on the primary cell.

[0720] Embodiments are also described herein for PUCCH resource allocation with a single ePDCCH resource set. For example, if the eCCE and / or eREG units in the ePDCCH may be defined similarly to the legacy PDCCH, the corresponding PUCCH resources may be:

[0721]

number

[0722] and for transmission modes supporting up to two transport blocks, the PUCCH resource

[0723]

number

[0724] teeth,

[0725]

number

[0726] is defined or derived by, where n eCCE is the number of the first CCE used to transmit the corresponding PDCCH within the ePDCCH region (e.g., the lowest eCCE index used to construct the PDCCH),

[0727]

number

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

[0729]

number

[0730] can be configured by higher layers.

[0731]

number

[0732] ξ may be dynamically calculated based on PCFICH detection (eg, detection of the number of OFDM symbols) and the system bandwidth.

[0733]

number

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

[0735]

number

[0736] This is combined with

[0737]

number

[0738] can be configured by higher layers.

[0739] In an embodiment, the PUCCH resource is

[0740]

number

[0741] and

[0742]

number

[0743] n so that is configurable by higher layers eCCE For transmission modes that support up to two transport blocks, the PUCCH resource

[0744]

number

[0745] teeth,

[0746]

number

[0747] can be given by

[0748] In addition, if the WTRU or UE may be configured for MU-MIMO transmission, the corresponding PUCCH resources may be

[0749]

number

[0750] and for a transmission mode that supports multiple (e.g., up to two) transport blocks, the PUCCH resource

[0751]

number

[0752] teeth,

[0753]

number

[0754] where n MU may be determined as at least one of a parameter that may be associated with an antenna port for a UE-specific DMRS, a parameter similar to an ARI configured by higher layer signaling, a parameter that may be similar to an ARI carried in the TPC field of a DL assignment message of the (e)PDCCH of the secondary serving cell (e.g., Rel-10-like), and / or a pre-determined parameter.

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

[0756]

number

[0757] and for transmission modes supporting up to two transport blocks, the PUCCH resource

[0758]

number

[0759] teeth,

[0760]

number

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

[0762]

number

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

[0764]

number

[0765] can be configured by higher layers.

[0766]

number

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

[0768]

number

[0769] teeth,

[0770]

number

[0771] In other words

[0772]

number

[0773] Can be combined with

[0774]

number

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

[0776]

number

[0777] and for transmission modes supporting up to two transport blocks, the PUCCH resource

[0778]

number

[0779] teeth,

[0780]

number

[0781] where nMU may be determined as at least one of a parameter associated with an antenna port for a UE-specific DMRS, a parameter similar to an ARI configured by higher layer signaling, a parameter similar to an ARI carried in the TPC field of a DL assignment message of the (e)PDCCH of the secondary serving cell (e.g., Rel-10-like), and / or a pre-determined parameter.

[0782] For PUCCH format 3, the WTRU or UE may select the PUCCH resource from a set of parameters signaled in a pre-configured RRC through the use of a signaled resource selector, e.g., an ARI carried in a DL assignment message on the (e)PDCCH via the secondary serving cell.

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

[0784] A PDSCH transmission mode associated with the ePDCCH may further be provided and / or used as described herein. For example, for PDSCH transmission, several transmission modes may be available in 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. The transmission mode may be configured, for example, via higher layer signaling, to enable the eNB scheduler to select an appropriate transmission mode for PDSCH transmission. Table 3 shows the transmission modes supported in LTE / LTE-A. The ePDCCH may be used in transmission modes that use antenna ports 7-10 for PDSCH demodulation. If the WTRU or UE is configured in a particular transmission mode, such as transmission mode 2, which allows the WTRU or UE to use CRS for PDSCH demodulation, the WTRU or UE may monitor the legacy PDCCH for PDSCH reception. If a WTRU or UE may be configured to monitor the ePDCCH while the configured transmission mode for the PDSCH is 2 (e.g., transmit diversity mode), the WTRU or UE may monitor the legacy PDCCH to receive DCI associated with the PDSCH in the subframe. If a WTRU or UE may be configured to monitor the ePDCCH while the configured transmission mode for the PDSCH is 9, the WTRU or UE may monitor the ePDCCH to receive DCI in a WTRU- or UE-specific search space in the subframe where it is configured for ePDCCH reception.

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

[0786] Systems and / or methods for ePDCCH reception may be provided herein. For example, a WTRU or UE is configured with an ePDCCH or a legacy PDCCH, and the operation of the WTRU or UE receiving the 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 the ePDCCH configuration so that the WTRU or UE knows the ePDCCH resources before the RACH procedure. To receive broadcast information such as an SIB, the WTRU or UE may decode the SI-RNTI in the legacy PDCCH. The WTRU or UE may be configured to receive the legacy PDCCH and / or ePDCCH in the RACH procedure. In a contention-based RACH procedure, the WTRU or UE may receive the PDCCH configuration information in either msg2 or msg4, which may be sent from the eNB. In a non-contention-based RACH procedure, the WTRU or UE may receive PDCCH configuration information in handover / mobility information or msg2, which may be sent from the eNB. If the WTRU or UE may be configured for a particular PDCCH type, the WTRU or UE may blind decode DCI in the configured PDCCH region (e.g., legacy PDCCH or ePDCCH). If the WTRU or UE may be configured for a particular PDCCH type, the WTRU or UE may blind decode a common search space in the legacy PDCCH region and a 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 the PDCCH resources may be configured by higher layer signaling, there may be an ambiguity period during which the eNB cannot know whether the WTRU or UE is monitoring a legacy PDCCH or ePDCCH. In order for the WTRU or UE to receive the PDCCH regardless of the PDCCH configuration, at least one of the following may be used:

[0788] The eNB may transmit both the legacy PDCCH and the ePDCCH in the same subframe during the ambiguity period and may detect which PDCCH resource the WTRU or UE is monitoring from the DTX of the HARQ-ACK. The PUCCH resources for the legacy PDCCH and the ePDCCH may be defined independently.

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

[0790] Additionally, the PDCCH type may be configured by a legacy PDCCH or an ePDCCH with an activation timer. If the WTRU or UE monitors a legacy PDCCH, it may use a trigger PDCCH based on the legacy PDCCH and inform the WTRU or UE to monitor the ePDCCH from subframe n+x when a trigger PDCCH, which may be predefined or configured for x, may be received in subframe n. If the WTRU or UE monitors an ePDCCH, it may use a trigger ePDCCH based on the ePDCCH and inform the WTRU or UE to monitor the legacy PDCCH from subframe n+x when a trigger ePDCCH, which may be predefined or configured for x, may be received in subframe n.

[0791] A MAC CE using activation and / or deactivation commands may be used to configure the PDCCH type according to one embodiment. For example, the activation and / or deactivation commands may be sent using a timer such as x, such that if a WTRU or UE receives a 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] According to an example embodiment, when multiple component carriers may be configured, at least one of the following may be used to handle the ambiguity period: For example, a common search space may be defined in the legacy PDCCH of the PCell and cross-carrier scheduling may be activated. In addition, cross-carrier scheduling may be activated for the common search space and available in the legacy PDCCH region. WTRU- or UE-specific search spaces 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 where the ePDCCH candidates are located. Although described in the case of collisions between the ePDCCH and PRS, the described embodiments may be applied in other cases, for example, when the ePDCCH resources may collide with other signals, including other reference signals, or broadcasting channels. Although described for handling or avoiding collisions with other signals, the described embodiments may be applied in other cases, for example, to restrict or otherwise limit the ePDCCH to or from certain resource elements (REs), RBs, or subframes for some reason.

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

[0795] In an example embodiment, the information that a WTRU or UE may receive for a given cell may include one or more of: subframes that may be used for PRS transmission, a PRS configuration index, the number of DL subframes, the BW for PRS transmission, PRS muting information, a PRS period, a PRS offset, a PRS muting period, a PRS muting sequence (e.g., which PRS opportunities may be muted in each PRS muting period), and / or an indication as to whether the cell transmits a PRS. For PRS muting sequences that may be included as part of the PRS muting information, if a p-bit field may be used to represent a muting sequence of period p, the first bit of the field may correspond to the first PRS positioning occasion that may start after the beginning of SFN=0 of the cell in which the PRS muting sequence may be received by the WTRU or UE.

[0796] eNB scheduling may be used or performed in one embodiment. For example, the eNB may schedule and / or transmit the ePDCCH in a manner that avoids collisions between ePDCCH RBs and PRS RBs or reduces the impact of collisions. In a subframe in which the eNB can transmit a PRS in a given cell, the eNB may not schedule or transmit the ePDCCH in any RBs in that cell. In a subframe in which the eNB can transmit a PRS in a given cell, the eNB may not schedule or transmit the ePDCCH in RBs that overlap with the PRS BW in that cell, e.g., in RBs that may collide with PRS RBs in that cell. The eNB may configure the ePDCCH in a given cell so that it cannot collide with the PRS in a subframe in which the eNB can transmit the PRS in that cell. This may be applicable, for example, when the PRS BW cannot be the complete DL BW of the cell.

[0797] Whether an eNB schedules or transmits ePDCCH in some subframes or some RBs may be based on whether or to what extent ePDCCH DM-RS REs collide with PRS REs. For example, if one or more ePDCCH RBs may collide with PRS RBs in a given subframe in which the eNB may transmit PRS, one or more of the following may apply: The eNB may transmit the ePDCCH in a subframe or in a colliding RB if no ePDCCH DM-RS RE may collide with a PRS RE in the colliding RB; the eNB may not transmit the ePDCCH in a subframe or in a colliding RB if at least one ePDCCH DM-RS RE may collide with a PRS RE in the colliding RB; the eNB may not transmit the ePDCCH in a subframe or in a colliding RB if a particular ePDCCH DM-RS RE collides with a PRS RE in the colliding RB; the eNB may not transmit the ePDCCH in a subframe or in a colliding RB if at least a certain number of ePDCCH DM-RS REs collide with PRS REs in the colliding RB; the eNB may not transmit the ePDCCH in a subframe or in a colliding RB if collisions of ePDCCH REs and PRS REs in the colliding RB cause some or at least a certain number of antenna ports to become unusable in those RBs due to collisions of one or more ePDCCH REs and PRS REs; and / or the like.

[0798] For example, for collision handling, embodiments may be described herein that relate to a WTRU or UE receiving an ePDCCH. The WTRU may determine whether to monitor or attempt to decode ePDCCH candidates in certain subframes or RBs of a cell based on at least one or more PRS parameters or transmission characteristics for the cell. The WTRU or UE may consider subframes in which a PRS may be transmitted. For example, in subframes in which a PRS may be transmitted, the WTRU or UE may monitor or attempt to decode PDCCH candidates in those subframes, but may not (or may be allowed 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 the ePDCCH and / or PRS may be transmitted. For example, in subframes in which a PRS may be transmitted, the WTRU or UE may not (or may be allowed not to) attempt to monitor or decode ePDCCH candidate(s) in those subframes if the ePDCCH candidate(s) may be located in RBs that may collide with the PRS RBs. In subframes in which a PRS may be transmitted, the WTRU or UE may not (or may be allowed not to) do one or more of the following: monitoring or attempting to decode ePDCCH candidates in subframes if at least one of the ePDCCH candidates may be located in an RB that may collide with a PRS RB; monitoring or attempting to decode ePDCCH candidates in subframes if more than a certain number of ePDCCH candidates may be located in RBs that may collide with a PRS RB; monitoring or attempting to decode ePDCCH candidates in subframes if (e.g., each or all of) the ePDCCH candidates in those subframes may be located in RBs that may collide with a PRS RB; monitoring or attempting to decode ePDCCH candidates located in RBs that may collide with a PRS RB; and / or the like. In a subframe in which a PRS may be transmitted, the WTRU may (or may need to) attempt to monitor or decode one or more ePDCCH candidates located in RBs that may not collide with PRS RBs in its cell and / or some (e.g., each or all) ePDCCH candidates if there are no ePDCCH candidates that may be located in RBs that may collide with PRS RBs (e.g., if there is no overlap between the RBs in which the ePDCCH candidate(s) may be located and the PRS RBs).

[0800] Additionally, the WTRU or UE may consider the subframes and REs in which the PRS may be transmitted, and may also consider, for example, whether or to what extent the PRS REs may collide with ePDCCH DM-RS REs. In a subframe in which a PRS may be transmitted, the WTRU or UE may (or may need to) attempt to monitor or decode ePDCCH candidates located in RBs that may collide with PRS RBs if none of the ePDCCH DM-RS REs in the colliding RBs may collide with the PRS REs, and / or may not (or may be allowed not to) attempt to monitor or decode ePDCCH candidates located in RBs that may collide with PRS RBs if at least one ePDCCH DM-RS RE in the colliding RB may collide with the PRS REs, and / or may not (or may be allowed not to) attempt to monitor or decode ePDCCH candidates located in RBs that may collide with PRS RBs if some ePDCCH DM-RS REs in the colliding RB may collide with the PRS REs, and / or may not (or may be allowed not to) monitor or decode ePDCCH candidates located in RBs that may collide with PRS RBs if at least a certain number of ePDCCH DM-RS REs in the colliding RB may collide with the PRS REs. It may not be possible (or may be allowed not to) monitor or attempt to decode ePDCCH candidates located in RBs that may collide with the PRS RBs, and / or it may not be possible (or may be allowed not to) monitor or attempt to decode ePDCCH candidates located in RBs that may collide with the PRS RBs in cases where some, or at least a certain number, of antenna ports in the colliding RBs may become unavailable in those RBs due to collisions between one or more ePDCCH REs and the PRS REs, and / or the like.

[0801] In a subframe in which a PRS may be transmitted in a given cell, the WTRU or UE may receive the physical layer cell ID,

[0802]

number

[0803] is defined as, where

[0804]

number

[0805] where PRS v may be the physical layer cell identifier. shift The WTRU may determine which ePDCCH candidates it may (or may be required to) or may not (or may be allowed not to) monitor or attempt to decode based on at least one of the values ​​of the values ​​or the cyclic prefix (CP length) of the subframe or cell, which may be normal or extended, for example. One or more of these parameters may be used by the WTRU to determine the locations of PRS REs that the WTRU or UE may use to determine ePDCCH DM-RS REs that may collide with PRS REs.

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

[0807] In another embodiment, a search space fallback may be implemented or used. For example, for a WTRU configured for 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 the WTRU or UE configured for ePDCCH. If in a subframe a WTRU or UE configured for ePDCCH cannot (or may be allowed not to) attempt to monitor or decode ePDCCH candidates, e.g., according to one of the solutions 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 ePDCCH may fall 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. The fallback may occur or be used in a subframe in which a PRS is transmitted in the cell and / or may be based on at least one of PRS information (e.g., one or more of the information items described herein), PRS transmission parameters, physical layer cell ID, CP length (e.g., normal or extended) within the cell or subframe, the number of antenna ports configured for ePDCCH transmission, antenna port restrictions, and / or the like.

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

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

[0811] Additionally, the configuration of ePDCCH subframes or ePDCCH monitoring subframes is equivalent to the configuration of fallback subframes, and ePDCCH subframes or ePDCCH monitoring subframes may be treated in the opposite manner to fallback subframes. For example, the WTRU or UE and / or eNB may handle subframes that may not be configured as ePDCCH subframes or ePDCCH monitoring subframes in the manner described herein for subframes that may be configured as fallback subframes. The WTRU or UE and / or eNB may handle subframes that may be configured as ePDCCH subframes or ePDCCH monitoring subframes in the manner described herein for subframes that may not be configured as fallback subframes.

[0812] Embodiments for processing PRS REs may be described herein. For ePDCCH candidates that may be located in RBs that a WTRU or UE may attempt to decode in a subframe in which a PRS may be transmitted, the WTRU or UE may assume that for REs that may contain data (e.g., REs that may not contain CRS or DM-RS or CSI-RS), the ePDCCH may not be transmitted in REs that may collide with PRS REs. The WTRU or UE may assume that ePDCCH REs are rate-matched here and there for these REs and / or punctured in these REs accordingly.

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

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

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

[0816]

number

[0817] One or more of the following can be used:

[0818] Additionally, location or antenna port mapping may be used for DM-RS REs according to an example embodiment, e.g., for collision handling. The eNB may reposition DM-RSs in RBs where ePDCCH candidates may be located within subframes of a cell in which PRSs may be transmitted. In subframes in which the eNB may transmit PRSs in a given cell, the eNB may reposition DM-RS REs, such as ePDCCH DM-RS REs, to avoid collisions with PRS REs. The eNB may reposition DM-RS REs, such as ePDCCH DM-RS REs, if at least one DM-RS RE would otherwise collide with a PRS RE. The eNB may reposition DM-RS REs, such as ePDCCH DM-RS REs, that would otherwise collide with a PRS RE.

[0819] Some DM-RS REs whose locations may be moved may include one or more (e.g., which may include all) DM-RS REs that may collide with a PRS RE if not moved, one or more (e.g., which may include all) DM-RS REs that have the same carrier frequency as a DM-RS RE that may collide with a PRS RE if not moved, and / or one or more (e.g., which may include all) DM-RS REs at adjacent carrier frequencies to a DM-RS RE that may collide with a PRS RE if not moved (e.g., if a DM-RS RE at frequency X collides with a PRS RE, the DM-RS RE at an adjacent frequency to X may be moved).

[0820] In subframes where PRS may be transmitted, the interpretation of antenna ports by the eNB for DM-RS, such as ePDCCH DM-RS, may be modified. This interpretation may depend on the physical cell ID of the cell, the PRS V of the cell, shift , CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission.

[0821] The change in allocation may be frequency-related, for example, increasing or decreasing the frequency. The change in allocation may or may not involve a change in symbol. The change in allocation may involve the physical cell ID of the cell, the PRS v of the cell, shift , 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 in which an eNB can transmit a PRS, the eNB may change the placement of DM-RS REs, such as ePDCCH DM-RS REs, in some subframes to avoid or reduce collisions with PRS REs in subframes in which the eNB can transmit the PRS. These some subframes may include subframes in which the eNB can transmit the PRS and / or cannot transmit the PRS, e.g., some subframes may include all subframes. The eNB may change the placement as described above. In this cell (e.g., a cell in which the eNB can transmit the PRS), the eNB's interpretation of antenna ports for DM-RS, such as ePDCCH DM-RS, may be modified in some subframes to align with desired modifications in subframes in which the eNB can transmit the PRS. These some subframes may include subframes in which the eNB can transmit the PRS and / or cannot transmit the PRS, e.g., 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 REs, in a subframe based on where the PRS would be placed if the cell were to transmit the PRS. The eNB may modify the placement as described herein. In this cell (e.g., a cell where the eNB may or may not transmit a PRS), the eNB's interpretation of antenna ports for a DM-RS, such as ePDCCH DM-RS, may be modified in a subframe to match what would be the desired modification if the cell were to transmit the PRS.

[0824] The eNB may move the DM-RS REs or modify the antenna port interpretation in one or more of the manners described for the ePDCCH DM-RS REs in a given subframe. The eNB may, for example, move the DM-RS REs or modify the antenna port interpretation for the PDSCHs allowed by the ePDCCH in that subframe in the same or similar manner.

[0825] In subframes in which a PRS may be transmitted, the WTRU or UE may attempt to monitor or decode ePDCCH candidates using a modified DM-RS pattern (e.g., which may be different from the DM-RS pattern that may be used for the ePDCCH in subframes in which a PRS may not be transmitted). In these subframes (e.g., subframes in which a PRS may be transmitted), the WTRU or UE's interpretation of the antenna port for a DM-RS, such as an ePDCCH DM-RS, may be modified. This interpretation may include the physical cell ID of the cell, the PRS v of the cell, and the DM-RS pattern of the ePDCCH candidates. shift , 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 (which may include, for example, all subframes) of a cell that may transmit a PRS, the WTRU or UE may attempt to monitor or decode ePDCCH candidates using a modified DM-RS pattern (which may be different from the DM-RS pattern that may be used for ePDCCH in a cell that may not transmit a PRS). In these subframes (e.g., one or more subframes, which may include all subframes of a cell that may transmit a PRS), the WTRU or UE's interpretation of the antenna port for a DM-RS, such as an ePDCCH DM-RS, may be modified. This interpretation may include the physical cell ID of the cell, the PRS v of the cell, and the DM-RS pattern of the cell. shift , and / or the number of antenna ports configured for ePDCCH transmission.

[0827] The interpretation of the modified DM-RS pattern and / or antenna port depends on the PRS RB location, the PRS RE location, the physical layer cell ID of the cell, the PRS v shift , 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 may use a modified DM-RS pattern or antenna port interpretation to decode a PDSCH, such as a PDSCH allowed by an ePDCCH, that may use a modified DM-RS pattern or antenna interpretation. For example, the WTRU may use a modified DM-RS pattern, such as the same or similar pattern used for the ePDCCH DM-RS, to decode a PDSCH allowed by an ePDCCH in a subframe in which the ePDCCH uses the modified DM-RS pattern. In another example, the WTRU may use a modified antenna port interpretation, such as the same or similar interpretation used for the ePDCCH DM-RS, for a PDSCH allowed by an ePDCCH in a subframe in which the ePDCCH uses the modified antenna port interpretation.

[0829] Additionally, embodiments for antenna port restriction for DM-RS REs may be described, e.g., to handle collisions. For example, an eNB may impose antenna port restrictions on RBs in which ePDCCH candidates may be located within subframes of a cell in which PRSs may be transmitted. In subframes in which an eNB may transmit PRSs in a given cell, the eNB may restrict the use of some antenna ports for ePDCCH and / or PDSCH. Such restrictions may be based on the physical layer cell ID of the cell, the PRS v of the cell, and the like. shift , CP length (e.g., for a cell, subframe, or normal subframe), and / or the number of antenna ports configured for ePDCCH transmission. As an example, if antenna ports 7, 8, 9, and 10 can be configured for ePDCCH transmission, a restriction limiting ports 7 and 8 or ports 9 and 10 can be imposed in subframes in which PRSs can be transmitted, and this restriction can be based on the physical layer cell ID of the cell, the PRS v shift, and / or CP length (e.g., for a cell, subframe, or regular subframe).

[0830] In subframes in which the PRS may be transmitted, the WTRU or UE may monitor or attempt to decode ePDCCH candidates 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 restricted set of antenna ports used for the ePDCCH DM-RS, for PDSCHs allowed by the ePDCCH in subframes in which the ePDCCH uses a restricted set of antenna ports. If a restricted set of antenna ports may be used, the restricted set may replace a configured or other antenna port set in, for example, any of the solutions or embodiments described herein.

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

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

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

[0834] If an RE, such as an ePDCCH RE or an ePDCCH DM-RS RE, can override a PRS RE, collision between the RE and the PRS RE can be removed or avoided (e.g., the PRS RE or signal in the PRS RE cannot be transmitted). If collision between an RE and a PRS RE can be removed or avoided, e.g., by overriding, the WTRU can determine that there is no collision between the RE and the PRS RE. Based on this determination, the WTRU can make various decisions, such as whether to monitor or attempt to decode ePDCCH candidates that may be located in RBs or REs in subframes in which PRSs may be transmitted in the cell.

[0835] Blind decoding (e.g., optimization thereof) may be performed (e.g., for collision handling). For example, based on the configured ePDCCH resources, the WTRU or UE may perform multiple 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 in which PRS may be transmitted in the cell, the WTRU or UE may monitor or attempt to decode a subset of the configured RBs in which 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 on a subset of RBs (e.g., to recover the entire decoding for a subframe) and / or perform a set of blind decodings on a subset of RBs that is greater than or equal to the set for these RBs as part of the complete configuration, and may be less than or equal to the complete set for the complete configuration. For example, if the complete set of RBs corresponds to N blind decodings and the subset corresponds to M of these N, then when attempting to decode the subset (or only the subset), the WTRU or UE may use W blind decodings, where W may be N or M≦W≦N.

[0836] Additionally, in embodiments (e.g., for collision handling), the eNB may have or obtain knowledge regarding the positioning capabilities of WTRUs or UEs and / or which WTRUs or UEs 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 WTRUs or UEs and / or which WTRUs or UEs 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 via, for example, an LPPa interface or protocol. For a given or particular WTRU or UE (or WTRU or UE), this information may include one or more of: whether the WTRU or UE may have the capability to support 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 for a particular cell or cells (e.g., cells 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 PRS information may have been successfully received by the WTRU or UE, and / or the like. The PRS information may include one or more of the PRS transmission subframe, BW, RB, RE, muting information, and / or any other information related to the PRS (e.g., parameters used to determine the PRS information or enumerated information described herein).

[0837] The E-SMLC and / or another network entity may know whether the PRS information was successfully received by the WTRU or UE based on receiving an acknowledgement (ACK) or other indication from the WTRU or UE in response to successfully receiving this information, which may have been provided by the E-SMLC or other network entity. In the absence of an ACK or other indication 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] The WTRU or UE may also process PRS information from one or more sources (e.g., for collision handling). For example, the WTRU or UE may receive PRS information for a cell from at least one source, such as an E-SMLC, an eNB that controls the cell's transmission of PRS, another cell, or another network entity. The WTRU or UE may process the PRS information it receives as described herein.

[0839] A WTRU's or UE's knowledge of a cell's PRS transmission information may be stale or unreliable, for example, if the information may have been received from an E-SMLC or a network entity other than an eNB that may have control or knowledge of the PRS information. For example, an eNB may notify an E-SMLC or other network entity of changes when PRS transmission parameters for one or more cells change, but if the WTRU or UE receives PRS information for the cell and PRS information changes after, for example, some time, the PRS information known to the WTRU or UE may be inaccurate. This information may be 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 can (or can only) use PRS information it may receive from an eNB to determine, for example, how to process an ePDCCH in a cell or in a PRS subframe of a cell in which the PRS may be transmitted. The eNB may be the eNB responsible for PRS transmission in the cell or another eNB that may provide the WTRU or UE with configuration for that cell (e.g., as part of information provided in handover-related signaling). The WTRU or UE may not (or may not be allowed to) use PRS information it may receive from another source, such as an E-SMLC or another network entity, to determine, for example, how to process an ePDCCH in a cell or in a PRS subframe of a cell in which the PRS may be transmitted. This may be provided (or may be beneficial) when the eNB is not aware of which WTRUs or UEs may have obtained PRS information from another source, such as an E-SMLC or other network entity. The behavior of the WTRU or UE may be unknown to or unpredictable by the eNB if the WTRU or UE were to use information received from another source. The eNB may send different PRS information to the WTRU or UE than the information that may be sent to the WTRU or UE by the E-SMLC or other network entity to perform a particular action.

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

[0842] Furthermore (e.g., to handle collisions), embodiments may be described for handling collisions between ePHICH and PRS. In a subframe in which a PRS may be transmitted, one or more of the following may apply: if the ePHICH may collide with a PRS, the ePHICH may override the PRS; if the DM-RS REs for the ePHICH may collide with the PRS REs, the DM-RS REs for the ePHICH may override the PRS REs; and / or if the ePHICH REs may collide with the PRS REs, the ePHICH REs may be rate-matched around the PRS REs. The WTRU or UE may take this into consideration when attempting to monitor or decode the ePHICH.

[0843] One or more of the embodiments described herein for processing the ePDCCH or ePDCCH and a PRS may be applied to processing the ePHICH or ePHICH and a PRS. For example, a WTRU configured for ePDCCH and / or ePHICH may fall back to attempting to monitor or decode the PHICH and / or may not attempt to monitor or decode the ePHICH in subframes for which fallback may be configured, in subframes for which ePDCCH or ePDCCH monitoring or ePHICH or ePHICH monitoring may not be configured, in subframes in which a PRS may be transmitted, or in which collision or potential collision with a PRS in these subframes warrants such operation according to one or more embodiments described herein.

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

[0845] In one embodiment, such a procedure may typically be facilitated by the assumption that another reference signal that may be periodically measured, such as a cell-specific reference signal, may 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 may be physically transmitted from the same set of antennas. On the other hand, in embodiments with geographically distributed 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 a different location than the cell-specific reference signal. As such, the WTRU or UE may be informed via a reference signal (e.g., CSI-RS) that may share the same timing and / or other characteristics as the reference signal used for demodulation. Corresponding antenna ports (e.g., two antenna ports) may then be “pseudo-matched” so that the WTRU or UE can infer large-scale characteristics of a signal received from a first antenna port from a signal received from another antenna port. The “large-scale characteristics” may include one or more of delay spread, Doppler spread, frequency shift, average received power, receive timing, and the like. As described herein, the ePDCCH may be demodulated using these reference signals, which may be transmitted on antenna ports, such as antenna ports 7 through 10. To take advantage of the potential capacity of the ePDCCH and further take advantage of area division, the ePDCCH may also be transmitted from a cell's transmission point. To transmit the ePDCCH from a cell's transmission point, the user equipment (UE) may need to use and / or know one or more reference signals, such as CSI-RS, that may be pseudo-matched to the antenna ports used to demodulate the ePDCCH. Unfortunately, using and knowing such reference signals that may be pseudo-matched to the antenna ports used to demodulate the ePDCCH may be difficult because potentially signaled downlink control information tends to be available after the ePDCCH has been decoded.

[0846] As such, systems and / or methods for providing a demodulation reference timing indication may be disclosed herein. For example, a single demodulation reference timing may be provided and / or used. In such an embodiment (e.g., a first embodiment), the WTRU or UE may assume, identify, or determine that at least one pseudo-reference 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 higher layers (e.g., at least one of ports 15-23 of one configuration of CSI-RS reference signals). The network may transmit the ePDCCH to the WTRU or UE on the same transmission point corresponding to the predefined or preconfigured pseudo-reference antenna port. The network may also transmit the ePDCCH on a different transmission point if it knows that the large-scale characteristics of the reference signal transmitted from this point are similar enough so as not to affect demodulation performance. For example, in one embodiment, if antenna port 0 (CRS) may be defined to be a pseudo-reference antenna port, and if the CRS may be transmitted from nodes (including high power nodes and low power nodes), the network may transmit ePDCCH from a particular low power node if it knows that the received timing of the reference signal transmitted from that low power node is likely to be sufficiently close to the timing of the CRS.

[0847] To enable such an embodiment, the WTRU or UE may estimate at least one characteristic of at least one reference signal, such as a CSI-RS, known by the network to be transmitted from a given transmission point. Characteristics that may be measured may include at least one of received timing, average received power, frequency shift, Doppler spread, delay spread, and the like.

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

[0849] In one embodiment, to compute this estimate, the WTRU or UE may average over multiple antenna ports from which the reference signal may be transmitted. The WTRU or UE may also average over multiple subframes and multiple resource blocks (e.g., in the frequency domain). New measurement types may also be defined for each of the above characteristics.

[0850] The 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 element or physical layer signaling). Using these results, the network may determine whether transmission from a particular point is feasible based on or taking into account the antenna port (or reference signal) that the WTRU or UE assumes, identifies, or determines to 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 to be pseudo-matched may be too large, the network may transmit using the same transmission point as used for the CRS (at the expense of loss or splitting gain).

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

[0852] The network can also estimate whether some large-scale characteristics are similar (e.g., if the reception timing may be similar) by measuring uplink transmissions from the WTRU or UE, such as SRS, PUCCH, PUSCH, or PRACH, and the like, at different reception points that occupy the same space as the transmission points potentially used for the downlink transmissions.

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

[0854] If the WTRU or UE is provided with or may be informed about a demodulation reference timing with 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-RS configured for the WTRU or UE, such as CSI-RS1 and CSI-RS2, and the WTRU or UE may report CSI for both CSI-RS configurations, the FFT timing and fine time and / or frequency synchronization for PDSCH demodulation may follow one of the two CSI-RS configurations according to the demodulation reference timing indication.

[0855] Alternatively, if the WTRU or UE is informed of information regarding demodulation reference timing with respect to a 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 the CSI may be used for reference timing, the FFT timing and channel estimation filter coefficients for the CSI-RS may be used for PDSCH demodulation. For example, the WTRU or UE may assume, identify, or determine that the PDSCH and / or WTRU- or UE-specific demodulation RS (e.g., antenna ports 7-14) may be transmitted from the same quasi-matched antenna port. As such, if the WTRU or UE may be configured to monitor the ePDCCH (e.g., for each PRB set), the WTRU or UE may assume, identify, or determine that a first set of antenna ports (e.g., 15-22) are associated with or correspond to CSI-RS information and / or identify a mapping for the PDSCH, and that other antenna ports (e.g., 7-14 or other ports) may be quasi-co-located with respect to parameters such as Doppler shift, Doppler spread, mean delay, delay spread, and the like, as described above.

[0857] If the CRS may be used for the reference timing, then the FFT timing and channel estimation filter coefficients for the CRS may be used for PDSCH demodulation. Alternatively, a time and / or frequency offset for the CRS may be provided for PDSCH demodulation. If the WTRU or UE may be informed about the offset, then the WTRU or UE may apply the offset from the CRS. In an example embodiment, at least one of an FFT timing offset (ΔFFT), a time offset (ΔT), a frequency offset (ΔF), and the like may be provided.

[0858] If the PRS may be used for reference timing, similar WTRU or UE behavior as with either the CSI-RS or CRS may apply in such an embodiment.

[0859] In one embodiment, the demodulation reference timing may be signaled to the WTRU or UE in an implicit or explicit manner, and a single demodulation reference for a given time window (e.g., subframe or radio frame) may be applied, or multiple demodulation references may be used.

[0860] An implicit demodulation reference timing indication may be provided and / or used. In such an embodiment (e.g., the first solution), the demodulation reference timing may be tied to ePDCCH and / or PDCCH resources and implicitly signaled to the WTRU or UE. Since the DCI is received to demodulate the PDSCH, the demodulation timing reference may be inferred from the location of the ePDCCH and / or PDCCH resources on which the WTRU or UE can receive the DCI. At least one of the following methods may be used to implement the ePDCCH and / or PDCCH resource-based indication:

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

[0862] Additionally, as described herein, within an ePDCCH WTRU- or UE-specific search space, the search space subset may be tied to a demodulation timing reference. Thus, if the WTRU or UE is capable of performing blind decoding on the ePDCCH, the WTRU or UE may 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 is capable of receiving DCI via the ePDCCH, the WTRU or UE may assume, identify, or determine that the corresponding PDSCH may be transmitted from the same transmission point as the ePDCCH. Furthermore, for an ePDCCH common search space (e.g., as described herein), the WTRU or UE may assume, identify, or determine that the ePDCCH may be transmitted from the same transmission point as the CRS.

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

[0864] According to another embodiment (e.g., a second solution), the demodulation antenna port may be associated with a demodulation timing reference. If antenna ports 7-10 are available for ePDCCH and / or PDSCH demodulation, multiple pairs of quasi-co-located ports may be predefined. For example, the WTRU or UE may assume, identify, or determine that antenna ports {7, 8} and {9, 10} may be quasi-located, and the quasi-located pairs {7, 8} and {9, 10} may be associated with CSI-RS1 and CSI-RS2, respectively. In one such embodiment, the WTRU or UE may also assume, identify, or determine that the decoding timing reference for antenna port 7 may be the same as that for antenna port 8. Alternatively, the scrambling ID (n SCID ) also allows multiple n SCID n can be used and linked to the demodulation timing reference. SCID = 0 and n SCID If n = 1 may be used, the WTRU or UE may use, for example, SCID =0 is associated with CSI-RS1, and n SCID It may be assumed, identified or determined that n = 1 may be associated with CSI-RS2. SCID can be associated with an antenna port. For example, n SCID = 0 is used for antenna ports {7, 8}, n SCID = 1 may be used for antenna ports {9, 10}. As such, the WTRU or UE may SCID= 0 is used when the WTRU or UE can demodulate the signal based on antenna ports {7, 8}, and n SCID It may be assumed, identified, or determined that n = 1 may be used when the WTRU or UE can demodulate a signal based on antenna ports {9, 10}. SCID The mapping of antenna ports to n may consist of at least one of the following: SCID The mapping of antenna ports to n is predefined, and in one such embodiment, the quasi-collocated antenna ports are all the same n SCID n SCID The mapping of antenna ports to rx_rx_encoder_map_map_map can be configured by a broadcasting channel or higher layer signaling, and similar configurations can be performed.

[0865] The scrambling sequence is

[0866]

number

[0867] It is initialized by, where c init In N X ID can be a higher layer configurable value or a predefined value as the physical cell ID.

[0868] In another embodiment (e.g., a third solution), the downlink resource may be tied to a demodulation timing reference. In one such embodiment, depending on the location of the downlink resource relative to the E-PDSCH and / or PDSCH, the WTRU or UE can infer the demodulation reference timing. The downlink location may include a subset of downlink subframes and / or at least one PRB that may be configured to use a specific demodulation reference time. Optionally, the reference time may be used for demodulating antenna ports 7-14. Otherwise, the CRS may be used as the reference timing.

[0869] In yet another embodiment (e.g., a fourth solution), the demodulation reference timing may be defined by a time relationship between the CSI-RS and the CSI feedback. In such an embodiment, the WTRU or UE operation may be defined by at least one of the following: The WTRU or UE uses the latest CSI-RS received; ... k When PDSCH is CSI-RS k In one such embodiment, a subframe offset may be additionally defined such that the WTRU or UE may assume, identify, or determine that the demodulation reference timing may be changed according to the number of offset subframes.

[0870] In addition, the WTRU or UE may report the latest CSI feedback as CSI-RS k When PDSCH can be based on CSI-RS k where the latest CSI feedback may be at least one of aperiodic CSI reporting, periodic CSI reporting with PMI / CQI in which the demodulation reference timing may be kept unchanged if the latest CSI report type is RI, periodic CSI reporting with PMI / CQI / RI, offset subframes in which the demodulation reference timing may be changed according to the number of offset subframes, and the like.

[0871] An implicit indication of PDSCH demodulation information may also be provided and / or used as described herein. For example, as described herein, a method or procedure may be used to determine PDSCH demodulation information that may be used by a WTRU or UE after decoding a PDSCH in a subframe, for example. The PDSCH demodulation information may include one or more of the following: For example, the PDSCH demodulation information may include a reference signal (e.g., or antenna port) that may be assumed to be quasi-colocated with a reference signal (e.g., or antenna port) that may be used for PDSCH demodulation (e.g., including an index to a non-zero power CSI-RS resource). The PDSCH demodulation information may also include at least one parameter that may be used to determine the location of a resource element (RE) on which the PDSCH may be transmitted or on which the PDSCH may not be transmitted (e.g., due to rate matching), such as at least one parameter indicating the location of a CRS port on which the PDSCH may not be transmitted (e.g., the number of CRS ports, the CRS frequency shift), at least one parameter indicating the location of a zero-power CSI-RS on which the PDSCH may not be transmitted, such as an MBSFN configuration, a zero-power CSI-RS configuration, an indication of a PDSCH start symbol, at least one parameter indicating the location of a non-zero-power CSI-RS on which the PDSCH may not be transmitted, at least one parameter indicating the location of a resource element that may be used for an interference measuremen...

Claims

1. 1. A method implemented in a wireless transmit / receive unit (WTRU), comprising: receiving one or more radio resource control transmissions including information associated with a physical downlink control channel communication, the information comprising: (i) information indicating time and frequency resources for each of one or more sets of resources; and (ii) including information indicative of an association between a set of search spaces of the set of one or more search spaces and a set of resources of the one or more sets of resources; receiving one or more transmissions including one or more physical downlink control channel candidates of the set of search spaces in the time and frequency resources of the set of resources based on information indicating an association between the set of search spaces and the set of resources, the set of search spaces including, for each aggregation level of a plurality of aggregation levels, a corresponding number of physical downlink control channel candidates; Including, The method of claim 1, wherein the time and frequency resources of the set of resources include a plurality of extended resource element groups.

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

3. 2. The method of claim 1 , wherein a plurality of the extended resource element groups comprises contiguous extended resource element groups within the time and frequency resources of the set of resources, the contiguous extended resource element groups being mapped to the one or more extended control channel elements for centralized physical downlink control channel transmission.

4. 2. The method of claim 1 , wherein a plurality of the extended resource element groups comprises extended resource element groups interleaved within the time and frequency resources of the set of resources, the interleaved extended resource element groups being mapped to the one or more extended control channel elements for distributed physical downlink control channel transmission.

5. The method of claim 1 , wherein the plurality of extended resource element groups excludes time resources in the set of resources used for demodulation reference signals.

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

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

8. 2. The method of claim 1 , wherein each of the one or more sets of resources includes information indicating an index for a 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 of claim 1 , wherein one or more of the plurality of extended resource element groups comprises a fixed number of resource elements.

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

11. A wireless transmit / receive unit (WTRU) comprising circuitry including a receiver, a transmitter, and a processor, receiving one or more radio resource control transmissions including information associated with physical downlink control channel communications, said information comprising: (i) information indicating time and frequency resources for each of one or more sets of resources; and (ii) comprising information indicating an association between a set of search spaces of the set of one or more search spaces and a set of resources of the one or more sets of resources; receiving one or more transmissions including one or more physical downlink control channel candidates of the set of search spaces in the time and frequency resources of the set of resources based on information indicating an association between the set of search spaces and the set of resources, the set of search spaces including a corresponding number of aggregation levels and a corresponding number of physical downlink control channel candidates for each aggregation level of a corresponding number of aggregation levels; It is configured as follows: The time and frequency resources of the set of resources include a plurality of extended resource element groups.

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

13. 12. The WTRU of claim 11, wherein a plurality of the extended resource element groups include contiguous extended resource element groups within the time and frequency resources of the set of resources, the contiguous extended resource element groups being mapped to the one or more extended control channel elements for a centralized physical downlink control channel transmission.

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

15. The WTRU of claim 11 , wherein the plurality of extended resource element groups excludes time resources in the set of resources used for demodulation reference signals.

16. The WTRU of 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 of claim 11 , wherein the time and frequency resources of the set of resources define a subset of an available band in a frequency domain.

18. 12. The WTRU of claim 11, wherein each of the one or more sets of resources includes information indicating an index for a 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 of claim 11 , wherein one or more of the plurality of extended resource element groups includes a fixed number of resource elements.

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

21. 1. A method implemented in a network node, comprising: Transmitting one or more radio resource control transmissions including information associated with a physical downlink control channel communication, the information comprising: (i) information indicating time and frequency resources for each of one or more sets of resources; and (ii) including information indicative of an association between a set of search spaces of the set of one or more search spaces and a set of resources of the one or more sets of resources; transmitting one or more transmissions including one or more physical downlink control channel candidates of the set of search spaces in the time and frequency resources of the set of resources based on information indicating an association between the set of search spaces and the set of resources, the set of search spaces including, for each aggregation level of a plurality of aggregation levels, a corresponding number of physical downlink control channel candidates; Including, The method of claim 1, wherein the time 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, Transmitting one or more radio resource control transmissions including information associated with physical downlink control channel communications, the information comprising: (i) information indicating time and frequency resources for each of one or more sets of resources; and (ii) comprising information indicating an association between a set of search spaces of the set of one or more search spaces and a set of resources of the one or more sets of resources; transmit one or more transmissions including one or more physical downlink control channel candidates of the set of search spaces in the time and frequency resources of the set of resources based on information indicating an association between the set of search spaces and the set of resources, the set of search spaces including a corresponding number of aggregation levels and a corresponding number of physical downlink control channel candidates for each aggregation level of a corresponding number of aggregation levels; It is configured as follows: The time and frequency resources of the set of resources include a plurality of extended resource element groups.

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