DOWNLINK CONTROL CHANNEL IN A WIRELESS SYSTEM - Patent application

Abstract

To provide a wireless communication system that may enable flexible spectrum usage, deployment strategies, and an operation.SOLUTION: There are disclosed systems, methods, and means for implementing a flexible radio access communication system. The flexible radio access communication system may be supported using a spectrum of varying size, including aggregation of non-adjacent carriers in same and / or in different frequency bands. A wireless transmit / receive unit (WTRU) may receive first transmission via a common downlink control channel. The first transmission may include first control information. The first control information may include information regarding a configuration of a first dedicated downlink control channel of one or more dedicated control channels. The WTRU may receive second transmission via the first dedicated downlink control channel of the dedicated control channels. The second transmission may include second control information.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a downlink control channel in a wireless system. [Background technology]

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 209,797, filed Aug. 25, 2015, which is incorporated by reference herein as if fully set forth.

[0003] Orthogonal Frequency Division Multiplexing (OFDM) can be a signal format used for data transmission in Long Term Evolution (LTE) and IEEE 802.11 communication systems. OFDM can divide the spectrum into multiple parallel orthogonal subbands. The subcarriers can be shaped using rectangular windows in the time domain, resulting in sinc-shaped subcarriers in the frequency domain. OFDMA can benefit from tight control of frequency synchronization and uplink timing alignment within the duration of the cyclic prefix to maintain orthogonality between signals and reduce inter-carrier interference. Summary of the Invention [Problem to be solved by the invention]

[0004] Such synchronization may be less suitable in systems where a wireless transmit / receive unit (WTRU) is simultaneously connected to multiple access points. For example, when there is aggregation of fragmented spectrum for WTRU transmissions, additional power reduction may be applied to uplink transmissions in order to comply with spectral emission guidelines for adjacent bands. [Means for solving the problem]

[0005] The wireless communication system may enable flexible spectrum usage, deployment strategies, and operations. A wireless transmit / receive unit (WTRU) and / or one or more base station devices / access points may be configured to utilize spectrum of varying size, including, for example, aggregation of non-contiguous carriers in the same and / or different frequency bands (e.g., licensed or unlicensed), to implement the flexible wireless access communication system. The WTRU and / or base station device may utilize one or more (e.g., different) duplex methods to implement the flexible wireless access communication system. In the case of time division duplex (TDD), the WTRU and / or base station device may utilize dynamically changeable DL / UL allocation to implement the flexible wireless access communication system. The WTRU and / or base station device may utilize variable TTI lengths to implement the flexible wireless access communication system. The WTRU and / or base station device may utilize scheduled and unscheduled transmissions to implement the flexible wireless access communication system. The WTRU and / or base station device may utilize synchronous and asynchronous transmission to implement the flexible radio access communication system. The user plane may be separated from the control plane. The WTRU and / or base station device may utilize multi-node connectivity to implement the flexible radio access communication system.

[0006] The WTRU and / or base station device may utilize resource elements to implement a flexible radio access communication system. Different types of resource elements may be defined, determined, and / or used. For example, resource elements (REs) may be defined, determined, and / or used. Different types of REs may be defined, determined, and / or used for different types of transmissions. Different types of REs may be defined, determined, and / or used based on one or more of a frequency space and / or a time length. Resource blocks (RBs) may be defined, determined, and / or used. For example, an RB may include one or more resource elements. For example, one or more (e.g., different) types of RBs may be defined, determined, and / or used for different types of transmissions. For example, one or more (e.g., different) types of RBs may be defined, determined, and / or used depending on which type of one or more REs are included in the RB. The information regarding the determined RB type may be transmitted to a wireless transmit / receive unit (WTRU). For example, the WTRU may receive the information regarding the determined RB type from a base station device.

[0007] The WTRU and / or base station device may utilize flexible physical resource definition information to implement a flexible radio access communication system. For example, the WTRU may receive flexible physical resource definition information from the base station device. The WTRU may receive RE and / or RB definitions (e.g., RE and / or RB definitions having a flexible structure) from the base station device. The WTRU may receive control channel resource unit definition information. For example, the WTRU may receive control resource element (CRE) and / or control resource element group (CREG) definition information to configure and / or implement a flexible radio access communication system. By using flexible resource definitions (e.g., CRE, CREG, etc.), the WTRU may be configured to dynamically and / or semi-statically utilize different resource types, e.g., for different types of transmissions and / or transmissions for different purposes / names / use cases. Different types of transmissions, using different waveform types and / or different RF processing chains, etc., may be used depending on the resource type.

[0008] The WTRU and / or the base station device may utilize the control channel resource configuration information to implement a flexible radio access communication system. For example, the WTRU may receive the control channel resource configuration information from the base station device. The control channel resource configuration information may be based on a service type. For example, the control channel resource configuration information may be based on a hierarchical control channel structure, a flexible control resource configuration, and / or a search space configuration. The search space configuration may be provided according to the service type and / or a collision handling when more than one search space is used.

[0009] The WTRU and / or base station device may utilize the control information to configure and / or implement the flexible radio access communication system. For example, the WTRU may receive cyclic redundancy check (CRC) attachment information from the base station device based on a service type and / or based on a payload size. The WTRU may receive, for example, a start and / or stop indication (e.g., for repeated transmissions) from the base station device.

[0010] The WTRU and / or base station device may utilize the WTRU report information. For example, the WTRU and / or base station device may utilize the WTRU report information to configure and / or implement a flexible radio access communications system. For example, the WTRU and / or base station device may utilize the WTRU report information for link adaptation of the control channel. The WTRU and / or base station device may utilize the control channel processing time report information to configure and / or implement a flexible radio access communications system. The WTRU and / or base station device may utilize the preferred search space and / or CC candidate report information to configure and / or implement a flexible radio access communications system.

[0011] The WTRU and / or base station device may use a transmission scheme to implement a flexible radio access communication system. For example, the WTRU and / or base station device may use a CP-based OFDM transmission scheme that may utilize a downlink physical layer. The downlink physical layer may vary in pilot signal density and / or location. The WTRU and / or base station device may use a downlink transmission scheme that may be based on a multi-carrier waveform.

[0012] The WTRU and / or base station device may use spectrum flexibility. Spectral flexibility may enable the WTRU and / or base station device to be deployed in different frequency bands having different characteristics. For example, a high degree of spectrum flexibility may enable deployment in different frequency bands having different duplex configurations. The WTRU and / or base station device may achieve bandwidth flexibility in a flexible radio access wireless communication system. Bandwidth flexibility may be achieved because RF requirements for an operating bandwidth in a band (e.g., a given maximum operating bandwidth) may be met without introducing additional allowed channel bandwidth for that operating band.

[0013] The WTRU and / or base station device may utilize a flexible deployment strategy and / or flexible operation. The flexible deployment strategy and / or flexible operation may include flexible spectrum allocation. The flexible deployment strategy and / or flexible operation may enable deployment in different and / or variable sized available spectrum, including contiguous and non-contiguous spectrum allocation in the same or different bands. The WTRU and / or base station device may support narrowband and / or wideband. The WTRU and / or base station device may support one or more (e.g., different) duplexing methods.

[0014] The WTRU and / or base station device may organize downlink and / or uplink transmissions into radio frames. A radio frame may be characterized by one or more fixed aspects (e.g., location of a downlink control channel) and / or one or more varying aspects (e.g., transmission timing, type of transmission supported). A basic time interval (BTI) may be represented by an integer number of one or more symbols. The symbol duration may be a function of the subcarrier spacing applicable to the time-frequency resource. In case of FDD, the subcarrier spacing may differ between the uplink carrier frequency fUL and the downlink carrier frequency fDL for a given frame. A transmission time interval (TTI) may be the minimum time supported by the system between transmissions (e.g., between successive transmissions).

[0015] The WTRU and / or base station device may support a scheduling function at the MAC layer. Scheduling modes that may be supported may include network-based scheduling and / or WTRU-based scheduling. For network-based scheduling and / or WTRU-based scheduling, the scheduling information may be valid for one or more TTIs. Network-based scheduling may enable the network to manage radio resources (e.g., available radio resources assigned to different WTRUs). For example, network-based scheduling may enable the network to manage available radio resources assigned to different WTRUs to optimize sharing of such resources. WTRU-based scheduling may enable the WTRU to access (e.g., opportunistically access) uplink resources when needed and with minimal latency. WTRU-based scheduling may enable the WTRU to access uplink resources in a set of shared and / or dedicated uplink resources (e.g., dynamic or fixed uplink resources) assigned by the network.

[0016] The WTRU and / or base station device may use a resource element (RE) as a resource unit (e.g., a smallest resource unit) in a physical resource grid. One or more (one or more) REs may be defined in the physical resource grid. An RE may include one or more (one or more) of the following: subcarriers of a multicarrier waveform in a time symbol, a time symbol, a sequence of modulated symbols where multiple sequences may be used to carry data symbols, and / or resource units that may carry data symbols.

[0017] A WTRU and / or base station device may use one or more (one or more) downlink control channels (and / or downlink control channel types). For example, the one or more (one or more) downlink control channels (and / or downlink control channel types) may be used based on one or more (one or more) of a traffic type for a data channel, an information type carried in the control channel, a reference signal, an RB type used for downlink control channel transmission, a SOM, and / or a WTRU type (or category) that can receive or monitor the control channel. Downlink control channel may be used interchangeably with downlink control channel type, control channel, and control channel type.

[0018] The WTRU and / or base station device may use the downlink control channel based on a traffic type of a data channel scheduled by the downlink control channel. A first type of downlink control channel may be used for a first traffic type, and a second type of downlink control channel may be used for a second traffic type. The traffic type may be data traffic that may use a low latency connection. The traffic type may be data traffic that may use a narrowband transmission. The traffic type may be data traffic that may use a transmission with high reliability. The traffic type may be control traffic that may carry a broadcast or multicast transmission. The traffic type may be control and / or data traffic that may be transmitted and / or received between WTRUs.

[0019] The WTRU and / or base station device may use a downlink control channel based on the WTRU capabilities. A first downlink control channel type may be used for a WTRU with limited WTRU capabilities. A second downlink control channel type may be used for a WTRU with full WTRU capabilities. The WTRU capabilities may include a supportable bandwidth, a number of receive antennas, a number of transmit antennas, a receiver beamforming capability, and / or a multi-antenna receiver type. The downlink control channel may be defined, determined, and / or used based on a reference signal. For example, the first downlink control channel may be associated with a first type of reference signal and / or the second downlink control channel may be associated with a second type of reference signal (e.g., WTRU-specific).

[0020] The WTRU and / or base station device may define a control resource element (CRE) with one or more (one or more) REs. CRE may be used interchangeably with resource element group (REG) and extended REG (EREG). CRE may be defined and / or determined with a certain number of REs. The REs available for CRE may be referred to as REs, which may be used for control channels. The WTRU may know the configuration of higher priority signals.

[0021] A CRE may be defined with a variable number of REs. For example, the number of REs per CRE may be determined based on the RE type for the RE in the associated CRE. A CRE that may include a first type of RE may be defined with a first number of REs. A CRE that may include a second type of RE may be defined with a second number of REs. The number of REs per CRE may be determined based on the RB type (e.g., based on the RB type of the RB in which the CRE may be placed). A CRE in a first type of RB may be defined with a first number of REs. A CRE in a second type of RB may be defined with a second number of REs. One or more (one or more) CREs may be defined for a time cycle. The number of REs per CRE may be determined based on the number of available REs in the RB.

[0022] The WTRU and / or base station device may use one or more (one or more) CRE types. The CRE type may be determined based on the control channel type and / or based on the RE type. The CRE type for the first control channel may be defined and / or configured with REs located in the same time symbol. The CRE type for the second control channel may be defined and / or configured with REs located in the same subcarrier. The CRE type may be determined based on the RB type (e.g., based on the RB type of the configured RB for the control channel). One or more (one or more) RBs may be configured for the control channel. The CRE type may be determined based on the RE type of the REs that may be grouped to form the CRE. For example, if the CRE is defined or configured with REs that may be of a defined RE type, the CRE type may be determined based on the RE type of the RE associated with the CRE. The CRE type may be determined based on the configuration, WTRU capability and / or category, traffic type, CP length used for the waveform, and / or subframe type.

[0023] The WTRU and / or base station device may define and / or configure a control resource element group (CREG). For example, a control resource element group (CREG) may be defined and / or configured with a group of one or more (one or more) CREs. CREG may be used interchangeably with control channel element (CCE) and / or enhanced CCE (ECCE). CREs having the same type may be grouped to form a CREG. The CREG type may be determined based on the CRE type. CREs may be grouped to form a CREG.

[0024] The WTRU and / or base station device may define and / or use one or more (one or more) CREG types. The CREG type for a downlink control information (DCI) transmission and / or a downlink control channel may be determined based on a channel type (e.g., an associated channel type). The WTRU and / or base station device may use a reference signal to demodulate the CRE and / or CREG. One or more (one or more) reference signal structures may be used for the downlink control channel. A first reference signal structure may be a cell-specific reference signal. The cell-specific reference signal may be used for one or more (one or more) downlink channels. A second reference signal structure may be a dedicated reference signal. The dedicated reference signal may be used for a particular downlink channel. The dedicated reference signal may be used for a data channel. The dedicated reference signal may be transmitted in a localized resource. The dedicated reference signal may be located within a resource that may be allocated, received, and / or decoded by the WTRU.

[0025] The WTRU and / or base station device may use a hierarchical downlink control channel structure. A common downlink control channel and / or one or more dedicated downlink control channels may be used. A common downlink control channel may be transmitted to and / or received by one or more WTRUs regardless of service type, traffic type, transmission type, WTRU category, and / or WTRU capabilities. A dedicated DL control channel may be transmitted to and / or received by a WTRU with a defined service type, traffic type, transmission type, WTRU category, and / or WTRU capabilities.

[0026] A nominal system bandwidth may be defined using a subset of the total system bandwidth. Frequency bands other than the nominal system bandwidth may be used based on an indicated or received configuration from the nominal system bandwidth. A common DL control channel may be transmitted from a base station device (e.g., eNB) and / or received by a WTRU in the nominal system bandwidth. A dedicated DL control channel may be configured in a frequency band within the total system bandwidth. For example, a dedicated DL control channel for a control channel type may be located in a frequency band used and / or configured for a traffic type associated with the control channel type. A dedicated DL control channel for a traffic type may be located in a frequency band assigned and / or used for the traffic type. One or more (one or more) dedicated DL control channels may be located in different frequency bands that may be associated with a traffic type. The time / frequency location of the dedicated DL control channel may be predefined within a frequency band that may be configured for a traffic type and / or service type.

[0027] The nominal system bandwidth may be located in different frequency regions based on one or more of the service type, traffic type, WTRU category, and / or WTRU capabilities. For example, the nominal system bandwidth for a wideband service may be located in a different frequency region than the frequency region for a massive MTC (mMTC) service (e.g., mMTC1212). The WTRU may find the nominal system bandwidth using a defined synchronization signal. The synchronization signal type may be determined based on one or more of the service type, traffic type, WTRU category, and / or WTRU capabilities.

[0028] The WTRU and / or base station device may use a search space. For example, a search space may be used in which one or more control channel (CC) candidates may be placed. The number of CC candidates in the search space may be determined based on one or more service types and / or traffic types. The number of CC candidates in the search space may be determined based on WTRU capabilities and / or categories. The WTRU capabilities and / or categories may include one or more of a supportable uplink and / or downlink bandwidth, a number of carriers, a number of transmit and / or receive antennas, and / or a receive processing time. The number of CC candidates in the search space may be determined based on time and / or frequency resources, and / or the number of CC candidates in the search space may be determined based on an associated reference signal type. The reference signal type may be replaced by a CRE type, a CREG type, or an RB type. A search space associated with a defined service type may include a smaller number of CC candidates. A search space associated with another service type may include a larger number of CC candidates. The search space associated with a defined service type may include CC candidates that can use the same type of CRE and / or CREG.

[0029] The WTRU and / or base station device may use downlink control information (DCI) to implement a flexible radio access communication system. The DCI may be used to schedule downlink data and / or uplink data. The DCI may include one or more (one or more) of a resource allocation, a modulation and coding scheme, a start BTI, an end BTI, a transport block size, a HARQ process number, a new data indicator, a carrier indicator, a number of spatial layers, and / or an uplink power control field for an associated data channel.

[0030] To implement a flexible radio access communication system, one or more (one or more) search spaces may be configured for a WTRU. The WTRU may report associated channel status information for the configured search spaces. The WTRU may report received signal power levels of (e.g., each) configured search space. The WTRU may report the search space that may have the highest received signal power level. The WTRU may report an index of a preferred CC candidate within the search space. The WTRU may report its capability for downlink control channel processing time.

[0031] Systems, methods, and means for implementing a flexible radio access communication system may be disclosed. The flexible radio access communication system may be supported using spectrum of varying size, including aggregation of non-contiguous carriers in the same and / or different frequency bands. A wireless transmit / receive unit (WTRU) may receive a first transmission via a common downlink control channel. The first transmission may include first control information. The first control information may include information regarding a configuration of a first dedicated downlink control channel of the one or more (one or more) dedicated control channels. The WTRU may receive a second transmission via the first dedicated downlink control channel of the dedicated control channels. The second transmission may include second control information. The second control information may be associated with a transmission of a first transmission type. The dedicated downlink control channel may be used to provide control information associated with a different type of transmission. Effect of the Invention

[0032] A system, method and means are provided for implementing a flexible wireless access communication system. [Brief description of the drawings]

[0033] [Figure 1A]FIG. 1 illustrates an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a diagram of an example wireless transmit / receive unit (WTRU) that may be used within the communications system of FIG. 1A. [Figure 1C] 1B is a system diagram of an example radio access network and core network that can be used within the communication system of FIG. 1A. [Figure 1D] 1B is a system diagram of another example radio access network and core network that can be used within the communication system of FIG. 1A. [Figure 1E] 1B is a system diagram of another example radio access network and core network that can be used within the communication system of FIG. 1A. [Diagram 2] FIG. 2 illustrates an example of a transmission bandwidth that can be used by a wireless transmit / receive unit (WTRU). [Diagram 3] FIG. 2 illustrates an example of spectrum allocation. [Figure 4] FIG. 2 illustrates timing relationships in an exemplary time division duplex (TDD) frame structure. [Diagram 5] FIG. 2 illustrates timing relationships in an exemplary frequency division duplex (FDD) frame structure. [Figure 6] FIG. 13 is a diagram illustrating an example of a physical resource definition having a flexible system configuration. [Figure 7] FIG. 2 illustrates an example of multiplexing of multiple resource block (RB) types within a subframe. [Figure 8] A diagram showing examples of control resource element (CRE) types defined or configured based on RB type. [Figure 9] FIG. 1 illustrates an example control resource element group (CREG) type. [Figure 10] FIG. 2 illustrates an example hierarchical downlink control channel. [Figure 11] FIG. 2 illustrates an example mapping between downlink (DL) transport channels and DL control channels. [Figure 12] FIG. 2 illustrates an example of flexible spectrum allocation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] A detailed description of illustrative embodiments will now be given with reference to various figures. While this description provides detailed examples of possible implementations, it should be noted that the details are intended to be illustrative and in no way limit the scope of the present application.

[0035] 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 utilize one or more (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), and Single Carrier FDMA (SC-FDMA).

[0036] 1A, the 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, a core network 106 / 107 / 109, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of 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, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, and home appliances.

[0037] The communication 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 one or more of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, and / or the network 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each shown 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.

[0038] 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 the base station 114b may be configured to transmit and / or receive wireless signals within a particular geographical area, sometimes referred to as a cell (not shown). The 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, e.g., one for each sector of the cell. In another embodiment, the base station 114a may utilize multiple-input multiple-output (MIMO) technology and thus may utilize multiple transceivers for each sector of the cell.

[0039] The base stations 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 communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 115 / 116 / 117 may be established using any suitable radio access technology (RAT).

[0040] More specifically, as mentioned above, the communication system 100 may be a multiple access system and may utilize one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a in the RAN 103 / 104 / 105 and the WTRUs 102a, 102b, 102c 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 include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0041] 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).

[0042] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, 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), and GSM EDGE (GERAN).

[0043] The base station 114b of FIG. 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a workplace, a home, a vehicle, and a campus. 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 may not need to access the Internet 110 via the core network 106 / 107 / 109.

[0044] The RAN 103 / 104 / 105 may communicate 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, 102d. For example, the core network 106 / 107 / 109 may provide call control, billing services, mobile location-based 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, it will be appreciated that the RAN 103 / 104 / 105 and / or the core network 106 / 107 / 109 may communicate directly or indirectly with other RANs that utilize the same RAT as the RAN 103 / 104 / 105 or a different RAT. For example, in addition to connecting to the RANs 103 / 104 / 105 that may utilize E-UTRA radio technology, the core networks 106 / 107 / 109 may also communicate with another RAN (not shown) that utilizes GSM radio technology.

[0045] The core network 106 / 107 / 109 may also act 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) in 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 (one or more) RANs that may utilize the same RAT as the RAN 103 / 104 / 105 or a different RAT.

[0046] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities, e.g., 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 a base station 114a that may utilize a cellular-based wireless technology and with a base station 114b that may utilize an IEEE 802 wireless technology.

[0047] 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 subcombination of the above elements while remaining consistent with an embodiment. Also, embodiments contemplate that the base stations 114a, 114b and / or the nodes that the base stations 114a, 114b 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 or He NodeB), 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.

[0048] 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 conjunction 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, etc. 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. Although FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip. A processor such as the processor 118 may include integrated memory (e.g., the WTRU 102 may include a chipset that includes a processor and associated memory). The memory may refer to memory integrated with a processor (e.g., the processor 118) or otherwise associated with a device (e.g., the WTRU 102). The memory may be non-transitory. The memory may include (e.g., store) instructions (e.g., software and / or firmware instructions) that can be executed by a processor. For example, the memory may include instructions that, when executed, cause the processor to perform one or more of the implementations described herein.

[0049] 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 receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0050] 1B , the transmit / receive element 122 is shown as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, 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.

[0051] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, UTRA and IEEE 802.11.

[0052] The processor 118 of the WTRU 102 may be 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. In addition, the processor 118 may obtain information from and store data in any type of suitable memory, such as a non-removable memory 130, a removable memory 132, and / or a memory integrated with the processor 118. The non-removable memory 130 may include a random access memory (RAM), a 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 from, and store data in, memory that is not physically located on the WTRU 102, such as located on a server or home computer (not shown).

[0053] The processor 118 may receive power from the power source 134 and may be configured to 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), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0054] 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 a 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 may determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information using any suitable location determination implementation while remaining consistent with an embodiment.

[0055] 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 e-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.

[0056] 1C is a system diagram of the RAN 103 and the core network 106, according to an embodiment. As mentioned above, the RAN 103 may communicate with the WTRUs 102a, 102b, 102c over the air interface 115 utilizing UTRA radio technology. 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, 140c, each of which may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 115. The Node Bs 140a, 140b, 140c may each be associated with a particular cell (not shown) within the RAN 103. The RAN 103 may also include RNCs 142a, 142b. It will be appreciated that the RAN 103 may include any number of Node Bs and RNCs while remaining consistent with an embodiment.

[0057] As shown in FIG. 1C, Node Bs 140a, 140b can communicate with RNC 142a. Additionally, Node Bs 140c can communicate with RNC 142b. Node Bs 140a, 140b, 140c can communicate with their respective RNCs 142a, 142b via an Iub interface. The RNCs 142a, 142b can communicate with each other via an Iur interface. Each of the RNCs 142a, 142b can be configured to control the respective Node Bs 140a, 140b, 140c to which it is connected. Additionally, each of the RNCs 142a, 142b can be configured to implement or support other functionalities, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, and data encryption.

[0058] 1C may include 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. Although each of the above elements is 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 different from the core network operator.

[0059] 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 the MGW 144. The MSC 146 and MGW 144 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 traditional land-line communications devices.

[0060] 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 with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0061] As mentioned above, the core network 106 may also connect to the networks 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0062] 1D is a system diagram of the RAN 104 and the core network 107, according to an embodiment. As mentioned above, the RAN 104 may utilize E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the core network 107.

[0063] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0064] 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, etc. As shown in FIG 1D, the eNodeBs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0065] The core network 107 shown in Figure 1D may include a mobility management gateway (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. Although each of the above elements is 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 different from the core network operator.

[0066] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authentication of users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selection of a particular serving gateway during initial attachment of the WTRUs 102a, 102b, 102c, etc. 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.

[0067] The serving gateway 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally route and forward user data packets to / 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 is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0068] The serving gateway 164 may also be connected to a PDN gateway 166, which 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.

[0069] 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 traditional land-line communications devices. 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. In addition, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to the network 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0070] 1E is a system diagram of the RAN 105 and the core network 109, according to an embodiment. The RAN 105 may be an Access Service Network (ASN) that communicates with the WTRUs 102a, 102b, 102c over an air interface 117 using IEEE 802.16 wireless technology. As described further below, 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.

[0071] 1E, the RAN 105 may include base stations 180a, 180b, 180c and an ASN gateway 182, although it will be understood 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, 180c may each be associated with a particular cell (not shown) in the RAN 105 and each may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 117. In one embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. Thus, the base station 180a, for example, may 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, and quality of service (QoS) policy enforcement. The ASN gateway 182 may act as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network 109, etc.

[0072] The air interface 117 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an R1 reference point, which 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, which may be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0073] The communication link between each of the base stations 180a, 180b, 180c may be defined as an R8 reference point, which includes 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, which may include protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

[0074] 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, which includes protocols for facilitating, for example, data forwarding and mobility management functions. The core network 109 may include a Mobile IP Home Agent (MIP-HA) 184, an Authentication, Authorization, and Accounting (AAA) server 186, and a gateway 188. Although each of the above elements is shown as part of the core network 109, it will be understood that any one of these elements may be owned and / or operated by an entity different from the core network operator.

[0075] The MIP-HA may be responsible for IP address management and may enable 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 support of user services. The gateway 188 may facilitate interworking with other networks. For example, the gateway 188 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 traditional land-line communications devices. In addition, the gateway 188 may provide access to the network 112 for the WTRUs 102a, 102b, 102c, which may include other wired or wireless networks owned and / or operated by other service providers.

[0076] Although not shown in FIG. 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 interworking between a home core network and a visited core network.

[0077] For emerging next generation wireless communication systems (e.g., 5G systems), the air interface (e.g., a radio interface between a WTRU and one or more base stations and / or one or more other WTRUs) may be designed to attempt to enable improved Inter-bandwidth (IBB) performance, support industrial control and communications (ICC) applications, support vehicular applications (V2X), and / or support massive machine-type communications (mMTC). To support these diverse application types, flexible wireless communication architectures for transmissions between different devices in the network may be used.

[0078] To support flexible operation, baseband filtering of frequency domain waveforms may be utilized by the WTRU and / or base station device. Baseband filtering of frequency domain waveforms may enable aggregation of spectrum within a given RF transceiver path. For example, baseband filtering of frequency domain waveforms may enable effective aggregation of up to 150-200 MHz of total spectrum within a given RF transceiver path. Aggregation of spectrum across an operating band (e.g., across widely separated operating bands such as 900 MHz and / or 3.5 GHz) may use multiple RF transceiver chains. For example, aggregation of spectrum across widely separated operating bands may use multiple RF transceiver chains due to antenna size constraints and / or amplifier optimization design constraints. A WTRU implementation may include one or multiple (e.g., three) RF transceiver paths. For example, a WTRU implementation may include an RF transceiver path for a first frequency domain (e.g., an RF transceiver path below 1 GHz), an RF transceiver path for a second frequency domain (e.g., an RF transceiver path for a 1.8-3.5 GHz frequency range), and an RF transceiver path for a third frequency domain (e.g., an RF transceiver path for a 4-6 GHz frequency range). To support flexible operation, a massive MIMO antenna configuration may be utilized by the WTRU and / or base station device. The massive MIMO antenna configuration may be natively supported. Multiple frequency bands using spectrum of one or more sizes (e.g., varying sizes) may be aggregated. For example, a base station device may aggregate multiple frequency bands using spectrum of one or more sizes (e.g., varying sizes). A base station device may aggregate multiple frequency bands using spectrum of one or more sizes to achieve data rates on the order of tens of Mbps at the cell edge to peak data rates of several Gbps.Typical data rates can be on the order of several hundred Mbps.

[0079] For one or more (one or more) types of transmission, the WTRU and / or base station device may utilize ultra-low transmission latency to implement a flexible radio access communication system. For example, air interface latency (e.g., as low as 1 ms round trip time (RTT)) may be utilized by the WTRU and / or base station device to implement a flexible radio access communication system. Air interface latency (e.g., as low as 1 ms round trip time (RTT)) may be supported by a TTI in the range of 100-250 μs. Ultra-low access latency (e.g., time from initial system access to completion of transmission of the first user data plane unit) may be utilized by the WTRU and / or base station device to implement a flexible radio access communication system. Mobility for speeds in the range of 0-500 km / h may be utilized by the WTRU and / or base station device. IC and / or V2X may be implemented using 10e -6 It can support a packet loss rate of less than

[0080] The WTRU and / or base station device may utilize machine type communication (MTC) operation (such as narrowband operation) to implement a flexible radio access communication system. The WTRU and / or base station device may utilize an air interface that can support narrowband operation (e.g., using less than 200 KHz), extended battery life (e.g., up to 15 years of autonomy), and / or minimal communication overhead for small and / or infrequent data transmissions. For example, the WTRU and / or base station device may utilize an air interface that can support low data rates in the range of 1-100 kbps with access latencies of seconds to hours.

[0081] The WTRU and / or base station device may utilize narrowband operation to support massive MTC (mMTC) operation. The link budget may be comparable to that of LTE extended coverage and / or the link budget may be smaller than that of MTC devices (e.g., up to 200k / km 2 A large number of MTC devices (e.g., multiple MTC devices, such as LTE-LTE, LTE- ...

[0082] The WTRU and / or base station device may utilize a flexible radio access wireless communication system that may enable flexible spectrum usage, flexible deployment strategies, and / or flexible operation. The WTRU and / or base station device may utilize flexible operation to support the use of a spectrum of varying sizes. For example, the WTRU and / or base station device may utilize flexible operation that may support the use of a spectrum of varying sizes including aggregation of non-contiguous carriers in the same and / or different frequency bands (e.g., licensed or unlicensed). The WTRU and / or base station device may utilize narrowband and / or wideband to implement the flexible radio access communication system. The WTRU and / or base station device may utilize one or more (e.g., different) duplexing methods. In the case of time division duplex (TDD), the WTRU and / or base station device may utilize dynamically changeable DL / UL allocation. The WTRU and / or base station device may utilize variable TTI lengths. The WTRU and / or base station device may utilize scheduled and unscheduled transmissions. The WTRU and / or base station device may utilize synchronous and / or asynchronous transmissions. The user plane may be separated from the control plane. The WTRU and / or base station device may utilize multi-node connectivity.

[0083] The wireless communication system described herein (e.g., flexible radio access communication system) may be integrated with and / or operate with a legacy interface (or an evolution thereof). For example, the wireless communication system described herein may be integrated with and / or operate with at least a legacy interface (e.g., S1 interface, NAS) toward a legacy core network (CN) and a legacy interface (e.g., X2 interface including dual connectivity with LTE) toward an eNB. The wireless communication system described herein may enable legacy aspects. For example, the wireless communication system described herein may enable support for existing quality of service (QoS) and / or security mechanisms. The WTRU and / or base station device may utilize D2D / sidelink operation. The WTRU and / or base station device may utilize Licensed Assisted Access (LAA) using LBT to implement the flexible radio access communication system. The WTRU and / or base station device may utilize relaying.

[0084] The WTRU and / or base station device may utilize Orthogonal Frequency Division Multiplexing (OFDM). OFDM may be a signal format used for data transmission in Long Term Evolution (LTE) and / or IEEE 802.11 communication systems. The WTRU and / or base station device may utilize OFDM to divide the spectrum into multiple parallel orthogonal sub-bands. The WTRU and / or base station device may use a rectangular window in the time domain to shape the sub-carriers resulting in sinc-shaped sub-carriers in the frequency domain. Orthogonal Frequency Division Multiple Access (OFDMA) may benefit from tight control of frequency synchronization and / or uplink timing alignment within the duration of the cyclic prefix. For example, OFDMA may benefit from tight control of frequency synchronization and / or uplink timing alignment within the duration of the cyclic prefix to maintain orthogonality between signals and / or reduce inter-carrier interference. Such synchronization may be less suitable in systems where a wireless transmit / receive unit (WTRU) is simultaneously connected to multiple access points. A power reduction (e.g., additional power reduction) may be applied to the uplink transmission to comply with spectral emission guidelines for adjacent bands (e.g., when there is aggregation of fragmented spectrum for WTRU transmissions).

[0085] Stricter RF guidelines for the implementation of OFDM (e.g., CP-OFDM) can address some of the shortcomings of OFDM (e.g., CP-OFDM). For example, when operating using large amounts of contiguous spectrum that cannot require aggregation, some of the shortcomings of OFDM (e.g., CP-OFDM) can be addressed by stricter RF guidelines for implementation. CP-based OFDM transmission schemes can utilize a downlink physical layer that can be varied in pilot signal density and / or location.

[0086] The WTRU and / or base station device may utilize a downlink transmission scheme (e.g., a scheme that may be based on a multi-carrier waveform) to implement a flexible radio access communication system. The multi-carrier waveform may be characterized by high spectral suppression (e.g., lower side lobes and / or lower out-of-band (OOB) emissions). Waveform candidates may include OFDM-OQAM and / or UFMC (UF-OFDM).

[0087] The WTRU and / or base station device may utilize a multi-carrier modulation waveform to implement a flexible radio access communication system. The multi-carrier modulation waveform may divide a channel into sub-channels. The multi-carrier modulation waveform may modulate data symbols on sub-carriers within the sub-channels.

[0088] The WTRU and / or base station device may apply a filter to the OFDM signal per subcarrier in the time domain. The OFDM signal may be applied to a filter per subcarrier in the time domain to reduce OOB. For example, with OFDM-OQAM, the OFDM signal may be applied to a filter per subcarrier in the time domain to reduce OOB. OFDM-OQAM may cause low interference to adjacent bands, may not require large guard bands, and / or may not require cyclic prefixes. OFDM-OQAM may be a popular FBMC technique.

[0089] The WTRU and / or base station device may apply a filter to the OFDM signal in the time domain to reduce OOB emissions. For example, when using UFMC (UF-OFDM), the WTRU and / or base station device may apply a filter to the OFDM signal in the time domain to reduce OOB emissions. Filtering may be applied per subband. For example, filtering may be applied per subband to use spectrum fragments. Complexity may be reduced. UF-OFDM may be practical to implement. UF-OFDM may be better than OFDM. For example, UF-OFDM may be better than OFDM at the edges of the filtered spectrum.

[0090] Although the methods disclosed herein may be described with respect to OFDM-OQAM and / or UFMC (UF-OFDM) waveforms, the methods described herein may also be applied to other types of waveforms in flexible radio access wireless communication systems. For example, the disclosed subject matter may be disclosed with respect to OFDM-OQAM and / or UFMC (UF-OFDM) waveforms for purposes of illustration and without limitation.

[0091] The WTRU and / or base station device may utilize multiple waveforms and / or different types of waveforms. By utilizing multiple waveforms and / or different types of waveforms, the WTRU and / or base station device may be able to perform multiplexing in frequency of signals having non-orthogonal characteristics. The non-orthogonal characteristics may include different subcarrier spacing and / or coexistence of asynchronous signals without the use of complex interference cancellation receivers. Aggregation of fragmented pieces of spectrum in baseband processing may be facilitated as a lower cost alternative to aggregation as part of RF processing.

[0092] The WTRU and / or base station device may utilize different waveforms that may coexist within one or more (one or more) bands to implement a flexible radio access communication system. The different waveforms may coexist within the same band. The WTRU and / or base station device may utilize mMTC narrowband (e.g., using SCMA). The WTRU and / or base station device may combine different waveforms (e.g., CP-OFDM, OFDM-OQAM, and / or UF-OFDM) within the same band for one or more (e.g., all) aspects for downlink transmissions and / or for uplink transmissions.

[0093] The WTRU and / or base station device may utilize an uplink transmission scheme that may use a waveform. For example, the WTRU and / or base station device may utilize an uplink transmission scheme that may use the same or a different waveform as used for downlink transmission. Multiplexing of transmissions to and / or from WTRUs in the same cell may be based on FDMA and / or TDMA.

[0094] The WTRU and / or base station device may utilize spectrum flexibility (e.g., a high degree of spectrum flexibility). Spectral flexibility (e.g., a high degree of spectrum flexibility) may enable deployment in different frequency bands with different characteristics. For example, spectrum flexibility (e.g., a high degree of spectrum flexibility) may enable deployment in different frequency bands with different duplex configurations. Spectral flexibility (e.g., a high degree of spectrum flexibility) may enable deployment in different and / or variable sizes of available spectrum, including contiguous and non-contiguous spectrum allocations in the same or different bands. The WTRU and / or base station device may utilize variable timing aspects. For example, the WTRU and / or base station device may utilize variable timing aspects for multiple TTI lengths and / or asynchronous transmission.

[0095] The WTRU and / or base station device may utilize TDD and / or FDD duplexing. For FDD operation, the WTRU and / or base station device may utilize supplemental downlink operation using spectrum aggregation. FDD operation may support full-duplex FDD and / or half-duplex FDD operation. For TDD operation, the DL / UL allocation may be dynamic. For example, for TDD operation, the length of the downlink (DL) and / or uplink (UL) transmission interval may be set for each transmission opportunity, rather than for a fixed DL / UL frame configuration.

[0096] The WTRU and / or base station device may utilize different transmission bandwidths on the uplink and downlink. For example, FIG. 2 illustrates an example spectrum deployment for supporting a flexible radio access wireless communication system. As illustrated in FIG. 2, the transmission bandwidth may range from a nominal system bandwidth 202 (e.g., 5 MHz) to a maximum value. The maximum value may correspond to a system bandwidth 204 (e.g., 20 MHz). For single carrier operation, example supported system bandwidths may include 5 MHz, 10 MHz, 20 MHz, 40 MHz, and / or 80 MHz. The WTRU and / or base station device may utilize narrowband transmissions (e.g., up to 200 KHz) within the operating bandwidth for the MTC device.

[0097] The WTRU and / or base station device may utilize a system bandwidth to implement a flexible radio access communication system. The system bandwidth may refer to the maximum portion of spectrum that may be managed by the network for a given carrier. For a carrier, the portion that the WTRU supports (e.g., minimally supports) for cell acquisition, measurements, and / or initial access to the network may correspond to a nominal system bandwidth. The WTRU may be configured to use a channel bandwidth that may be within the system bandwidth (e.g., the entire system bandwidth). The configured channel bandwidth of the WTRU may include a nominal portion of the system bandwidth as shown in FIG. 2. For example, the configured channel bandwidth of the WTRU may include the UEx channel bandwidth 206 (e.g., 10 MHz), the UEy channel bandwidth 208 (e.g., 20 MHz), and / or the UEz channel bandwidth 210 (5 MHz).

[0098] A WTRU and / or base station device in a flexible radio access wireless communication system can be configured to utilize bandwidth in a flexible and / or dynamic manner. For example, a WTRU and / or base station device can achieve bandwidth flexibility because the RF requirements for an operating bandwidth in a band (e.g., a given maximum operating bandwidth) can be met without introducing additional allowed channel bandwidth for that operating band. Due to efficient support of baseband filtering of frequency domain waveforms, the RF requirements for a given maximum operating bandwidth in a band can be met without introducing additional allowed channel bandwidth for that operating band.

[0099] A WTRU and / or a base station device in a flexible radio access wireless communication system may utilize a physical layer. The physical layer may be band independent and / or may support operation in licensed bands. For example, the physical layer may be band independent and / or may support operation in licensed bands below 5 GHz and / or operation in unlicensed bands in the range of 5-6 GHz. For operation in unlicensed bands, the WTRU and / or a base station device may utilize an LBT Cat 4 based channel access framework (e.g., similar to LTE LAA).

[0100] A WTRU and / or a base station device in a flexible radio access wireless communication system may utilize frequency division multiplexing (FDM) operation. Downlink control channels and / or signals may support frequency division multiplexing (FDM) operation. For example, a WTRU may acquire a downlink carrier by receiving a transmission using a nominal portion of the system bandwidth. The WTRU may not be required to receive (e.g., not initially be required to receive) a transmission over the entire bandwidth managed by the network for the concerned carrier.

[0101] WTRUs and / or base station devices in a flexible radio access wireless communication system may utilize downlink data channels. The downlink data channels may be allocated on a bandwidth that may correspond to a nominal system bandwidth. For example, the downlink data channels may be allocated on a bandwidth that may correspond to a nominal system bandwidth, without any restrictions other than being within the WTRU's configured channel bandwidth. The network may operate a carrier having a system bandwidth (e.g., a 12 MHz system bandwidth) using a nominal bandwidth (e.g., a 5 MHz nominal bandwidth). Operating a carrier having a 12 MHz system bandwidth using a 5 MHz nominal bandwidth may allow devices supporting a maximum RF bandwidth of at most 5 MHz to acquire and / or access the system, while allocating +10 to -10 MHz of the carrier frequency to other WTRUs supporting up to 20 MHz worth of channel bandwidth.

[0102] FIG. 3 illustrates an example of spectrum allocation. For example, FIG. 3 illustrates an example of spectrum allocation utilized by a WTRU and / or a base station device on a nominal system bandwidth 302 (e.g., 5 MHz) and / or a system bandwidth 304 (e.g., 20 MHz). One or more modes of operation (e.g., SOM) may be conceptually assigned one or more subcarriers. For example, one or more modes of operation (e.g., spectrum operation modes (SOM)) may be conceptually assigned subcarriers 306 and / or subcarriers 308.

[0103] One or more spectrum operating modes (SOMs) may be used to meet one or more requirements for one or more transmissions. For example, a SOM may refer to a particular type of transmission scheme and / or a transmission scheme used to perform a type of communication (e.g., low latency communication, high reliability communication, etc.). A SOM may be defined according to one or more of a subcarrier spacing, a transmission time interval (TTI) length, and / or one or more reliability aspects (e.g., HARQ processing aspects). A SOM may include a secondary control channel. A SOM may be used to refer to a particular waveform and / or may be related to processing aspects (e.g., supporting coexistence of different waveforms in the same carrier using FDM and / or TDM). A SOM may be used when coexistence of FDD operations in a TDD band is supported (e.g., in a TDM or similar manner). A first type of SOM may be used to access a first network slice, and a second type of SOM may be used to access a second network slice. Multiple SOMs can be used simultaneously.

[0104] For single carrier operation, the WTRU and / or base station device may utilize spectrum aggregation to implement a flexible radio access communication system. The WTRU and / or base station device may support transmission and / or reception of one or more (one or more) transport blocks on a contiguous or non-contiguous set of physical resource blocks (PRBs) within an operating band (e.g., the same operating band). The transport blocks may be mapped to one or more (one or more) sets (e.g., separate sets) of PRBs.

[0105] The WTRU and / or base station device may utilize multi-carrier operation. For example, the WTRU and / or base station device may utilize multi-carrier operation using contiguous or non-contiguous spectrum blocks within an operating band (e.g., the same operating band) and / or across two or more operating bands. The WTRU and / or base station device may utilize aggregation of spectrum blocks using modes (e.g., different modes such as FDD and TDD) and using channel access methods below 6 GHz (e.g., different channel access methods such as licensed and / or unlicensed band operation).

[0106] The WTRU and / or base station device may utilize high flexibility for spectrum aggregation, which may not include the use of additional channels and / or band combinations. For example, the high flexibility for spectrum aggregation may not include the use of additional channels and / or band combinations, subject to the use of efficient baseband filtering in the frequency domain.

[0107] The WTRU and / or base station device may organize downlink and / or uplink transmissions into radio frames, which may be characterized by one or more fixed aspects (e.g., location of downlink control information) and / or one or more varying aspects (e.g., transmission timing, types of transmissions supported).

[0108] The WTRU and / or base station device may utilize a Basic Time Interval (BTI). The BTI may be defined as a time unit for defining or utilizing a SOM or transmission scheme. For example, the BTI may correspond to a symbol length, such as an OFDM symbol length. The BTI may be represented by an integer number of one or more (one or more) symbols. The symbol duration may be a function of a subcarrier spacing applicable to the time-frequency resource. In the case of FDD, the subcarrier spacing is the time interval (T) between the uplink carrier frequency f for a given frame. UL and the downlink carrier frequency f DL can vary between

[0109] The WTRU and / or base station device may utilize a transmission time interval (TTI). The TTI may be a minimum transmission time and / or a minimum time supported by the system between transmissions (e.g., successive transmissions). One or more (e.g., each) of the transmissions may be a downlink (TTI excluding a preamble (if applicable) and / or including control information (e.g., DCI for the downlink and / or UCI for the uplink). DL A TTI may be associated with one or more (e.g., different) Transport Blocks (TBs) for the uplink (UL TRx) and / or the uplink (UL TRx). A TTI may be represented by an integer number of one or more (e.g., different) BTIs. For example, as shown in FIG. 4, a TTI may be represented by a TTI n (x*BTI) 420, and / or the TTI can be expressed as TTI n+1 (y*BTI) 422. As shown in FIG. DL(n) (x*BTI) 420, and / or the TTI can be expressed as TTI DL(n+1) It can be expressed as (y*BTI)422.

[0110] Supported frame durations in a flexible radio access wireless communication system may enable alignment with legacy LTE timing structures. For example, supported frame durations may include 100 μs, 125 μs (1 / 8 ms), 142.85 μs (1 / 7 ms is two nCP LTE OFDM symbols), and / or 1 ms.

[0111] FIG. 4 illustrates timing relationships in an example TDD frame structure 400 of a flexible radio access wireless communication system. FIG. 5 illustrates timing relationships in an example FDD frame structure 500 of a flexible radio access wireless communication system. A WTRU and / or a base station device may utilize a frame. A frame may start with downlink control information (DCI) (such as 402 in FIG. 4 and / or 502 in FIG. 5). The DCI may be a fixed time duration t (such as 404 in FIG. 4 and / or 504 in FIG. 5). dci The time duration of the DCI may precede the downlink data transmission on a concerned carrier frequency (e.g., DL TRx, such as DL TRx 406 and / or 506). The concerned carrier frequency may be f UL+DL 408, and / or f in the case of FDD DL508. For TDD duplex, the frame may include a downlink portion (e.g., DCI and / or DL ​​TRx) and the frame may include an uplink portion (e.g., UL TRx, such as UL TRx 410 and / or 510). A switching gap (swg, such as swg 412), if present, may precede the uplink portion of the frame. For FDD duplex, the frame may include a downlink reference TTI and / or the frame may include one or more TTIs for the uplink. The start of the uplink TTI is determined by an offset (t offset 512 and other t offset ) may be used to derive the D2D / V2x / sidelink operation. For TDD, the WTRU and / or base station device may utilize D2D / V2x / sidelink operation in the frame. For example, for TDD, the D2D / V2x / sidelink operation in the frame may be supported by including the respective downlink control and / or forward transmissions in the DCI+DL TRx portion (if semi-static allocation of the respective resources is used) or in the DL TRx portion (for dynamic allocation) and the respective reverse transmissions in the UL TRx portion. For FDD, the WTRU and / or base station device may utilize D2D / V2x / sidelink operation in the UL TRx portion of the frame. For example, for FDD, the D2D / V2x / sidelink operation in the UL TRx portion of the frame may be supported by including the respective downlink control, forward, and reverse transmissions in the UL TRx portion (if dynamic allocation of the respective resources can be used).

[0112] The WTRU and / or base station device may utilize a scheduling function at the MAC layer. Scheduling modes that may be supported may include network-based scheduling for strict scheduling (e.g., strict scheduling with respect to resources, timing, and / or transmission parameters of downlink and / or uplink transmissions). Scheduling modes that may be supported may include WTRU-based scheduling for flexibility with respect to timing and / or transmission parameters. For network-based and / or WTRU-based scheduling, the scheduling information may be valid for one or more (one or more) TTIs. Network-based scheduling may enable the network to manage radio resources (e.g., available radio resources assigned to different WTRUs). For example, network-based scheduling may enable the network to manage available radio resources assigned to different WTRUs to optimize sharing of such resources. The WTRU and / or base station device may utilize dynamic scheduling. WTRU-based scheduling may enable the WTRU to access (e.g., opportunistically access) uplink resources when needed and with minimal latency. WTRU-based scheduling may enable a WTRU to access uplink resources within a set of shared and / or dedicated uplink resources (e.g., dynamic or fixed uplink resources) allocated by the network.

[0113] The WTRU and / or base station device may utilize synchronous and / or asynchronous opportunistic transmission. The WTRU and / or base station device may utilize contention-based and / or contention-free transmission. Association of data available for transmission and / or resources available for uplink transmission may be supported. The WTRU and / or base station device may utilize multiplexing of data having one or more (e.g., different) QoS requirements within a transport block (e.g., the same transport block). For example, the WTRU and / or base station device may utilize multiplexing of data having one or more (one or more) QoS requirements within a transport block as long as such multiplexing does not introduce adverse effects for services with the most stringent QoS requirements and / or does not introduce unnecessary waste of system resources.

[0114] The WTRU and / or base station device may utilize resource elements (REs). The REs may be used by the WTRU and / or base station device as resource units (e.g., smallest resource units) in a physical resource grid. The WTRU and / or base station device may define one or more (one or more) of the REs in the physical resource grid. The REs may be and / or include one or more of the following: The REs may be and / or include subcarriers of a multicarrier waveform in a time symbol (e.g., OFDM, Filtered OFDM, Filter Bank Multicarrier, or FBMC). For example, the REs may be and / or include a time symbol if the waveform is based on a single carrier. The REs may be and / or include a sequence of modulated symbols, where multiple sequences may be used to carry data symbols. For example, the modulated symbols may carry one or more sequences. Each sequence may be used to transmit a data symbol (e.g., QPSK, 16QAM, 64QAM). An RE may be and / or may contain a resource unit capable of carrying data symbols.

[0115] The terms waveform, multiplexing scheme, and modulation scheme may be used interchangeably. The terms waveform time symbol, modulated symbol, OFDM symbol, filtered OFDM symbol, FBMC symbol, and time symbol may be used interchangeably. The terms data symbol, constellation, QPSK, QAM, and offset QAM may be used interchangeably.

[0116] The WTRU and / or base station device may utilize one or more RE types. The WTRU and / or base station device may determine the RE type based on the frequency space (e.g., subcarrier spacing) and / or time length (e.g., symbol length). The WTRU and / or base station device may determine the frequency space and / or time length of the RE based on the frequency location. As shown in FIG. 6, the REs in the first frequency resource are classified into the following types: delta F1606 and / or Time Length delta The RE in the second frequency resource can be defined using the frequency space T1610. delta F2608 and / or Time Length delta It can be defined using T2612.

[0117] A resource block (RB) may be a set of REs. The WTRU and / or base station device may use one or more RB types. For example, a resource block may be one or more REs (e.g., a combination of one or more REs) in frequency (N RE,f ), and / or a number of REs in time (N RE,t ) The WTRU and / or base station device may determine the number of REs in time and / or frequency based on the RB type.

[0118] The WTRU and / or base station device may use one or more RB types. The WTRU and / or base station device may associate (e.g., each) RB type with a transmission mode (or scheme, SOM). The WTRU and / or base station device may configure the transmission mode (or scheme, SOM) via higher layer signaling and / or broadcast signaling. The WTRU and / or base station device may determine the transmission mode (or scheme, SOM) based on the WTRU capabilities. The transmission mode (or scheme, SOM) may be indicated from an associated downlink control channel. The WTRU and / or base station device may determine the transmission mode (or scheme, SOM) based on a time / frequency location of the associated downlink control channel. The WTRU and / or base station device may determine the transmission mode (or scheme, SOM) based on a downlink control candidate index (e.g., search space location).

[0119] The WTRU and / or base station device may determine the time and frequency location. For example, the WTRU and / or base station device may determine the time and frequency location based on a determined RB type that the WTRU may receive and / or that the WTRU may need to receive (and / or monitor, decode, measure, etc.). For example, the WTRU and / or base station device may determine the RB type based on the time and / or frequency location. The WTRU may be informed of the time and / or frequency location of the RB type that the WTRU may need to receive. An RB may include one or more REs (e.g., a set of REs). The REs within an RB (and / or RB type) may be REs of the same type (e.g., the same frequency interval and / or time length). The RB (and / or RB pair) may be used as a resource unit. For example, an RB (and / or RB pair) may be used as a minimum resource unit for scheduling data transmission.

[0120] Transmission mode, transmission scheme, and SOM may be used interchangeably.

[0121] The WTRU and / or base station device may determine the RB type. For example, the WTRU and / or base station device may determine the RB type based on one or more of the number of REs in frequency, the number of REs in time, and / or the RE type. The WTRU and / or base station device may associate the RE type with the RB type. If the network (and / or eNB, system, etc.) uses a certain type of RE, the WTRU and / or base station device may determine the RB type based on the number of REs in frequency and / or the number of REs in time. Table 1.0 shows examples of RB types. The RB type may be determined based on the number of REs in time and / or frequency, the subcarrier spacing of the REs, and / or the time symbol length of the REs.

[0122] One or more RB types may be defined. For example, one or more RB types may be defined with a time symbol (e.g., a single time symbol) having one or more subcarriers that may be used for a traffic type (e.g., a defined traffic type) that may use a low latency connection. One or more RB types may be defined with a subcarrier (e.g., a single subcarrier) having one or more time symbols that may be used for a defined traffic type that may use narrowband transmission. One or more RB types may be defined with one or more time symbols and one or more subcarriers that may be used for a traffic type (e.g., a defined traffic type) that may be characterized by high throughput performance.

[0123] [Table 1]

[0124] A WTRU and / or base station device may multiplex one or more RB types. For example, one or more RB types may be multiplexed within a subframe. A subframe may be a predefined time period and / or frequency bandwidth. A subframe may be defined as a set of RBs. FIG. 7 illustrates an example of multiplexing one or more RB types within a subframe. For example, FIG. 7 illustrates an example of multiplexing RB type-A 702, RB type-B 706, and / or RB type-C 704.

[0125] The WTRU and / or base station device may determine an RB type in a subframe based on a frequency location of the RB. The RB type in a subframe may be determined based on a time / frequency location of the RB. The RB type in a subframe may be determined based on a WTRU scheduled in the RB. For example, the WTRU may be configured to use an RB type (e.g., a determined RB type) for data transmission / reception. The scheduled RB may be determined as the configured RB type for the WTRU.

[0126] The WTRU and / or base station device may define an RB as a chunk of time and / or as a frequency resource. The WTRU and / or base station device may determine the number of REs for an RB based on a subcarrier number and / or a number of modulated symbols within the chunk of time and / or the frequency resource. The number of REs in an RB may be determined based on a type of modulation (e.g., OFDM, FBMC, etc.).

[0127] A WTRU and / or base station device may use one or more downlink control channels (and / or downlink control channel types). For example, the one or more downlink control channels (and / or downlink control channel types) may be used based on one or more of the traffic type for the data channel, the information type carried in the control channel, the reference signal, the RB type used for downlink control channel transmission, the SOM, and / or the WTRU type (or category) that can receive or monitor the control channel. Downlink control channel may be used interchangeably with downlink control channel type, control channel, and control channel type.

[0128] The WTRU and / or base station device may define (and / or, for example, determine and / or use) a downlink control channel. For example, the downlink control channel may be defined, determined, and / or used based on a traffic type of a data channel scheduled by the downlink control channel. The WTRU and / or base station device may use a first type of downlink control channel for a first traffic type (e.g., delay tolerant traffic). The WTRU and / or base station device may use a second type of downlink control channel for a second traffic type (e.g., low latency traffic). The traffic type may be data traffic that may use a low latency connection. The low latency connection may be referred to as a HARQ timing (or HARQ round trip time) that may be less than a predefined threshold. The round trip delay may be less than a predefined threshold. The traffic type may be data traffic that may use narrowband transmission. The traffic type may be data traffic that may use transmission with high reliability. The traffic type may be control traffic that may carry broadcast or multicast information. The traffic type may be control and / or data traffic that may be transmitted and / or received between WTRUs.

[0129] The WTRU and / or base station device may define (and / or, e.g., determine and / or use) a downlink control channel based on the WTRU capabilities. A first downlink control channel type may be used for a WTRU with limited WTRU capabilities. A second downlink control channel type may be used for a WTRU with full WTRU capabilities. The WTRU capabilities may include a supportable bandwidth (e.g., RF and / or baseband bandwidth supported by the WTRU). The WTRU capabilities may include a number of receive antennas (e.g., number of RF chains or antennas at a WTRU receiver). The WTRU capabilities may include a number of transmit antennas (e.g., number of RF chains or antennas at a WTRU transmitter). The WTRU capabilities may include receiver beamforming capabilities. The WTRU capabilities may include a multiple antenna receiver type.

[0130] The WTRU and / or base station device may define downlink control channels based on the reference signals. For example, a first downlink control channel may be associated with a first type of reference signal (e.g., cell-specific). A second downlink control channel may be associated with a second type of reference signal (e.g., WTRU-specific).

[0131] The WTRU and / or base station device may define a control resource element (CRE). A CRE may be defined using a group of one or more REs. CRE may be used interchangeably with resource element group (REG) and enhanced REG (EREG).

[0132] The WTRU and / or base station device may define (and / or determine) a CRE with a certain number of REs. For example, the CRE may be N RE,C It may contain N REs. RE,C N can be the nominal number, or the number of available REs.RE,C can be a nominal number, and the number of REs available for the CRE is N RE,C For example, if one or more REs or CREs are reserved for higher priority channels (e.g., reference signals, synchronization signals, broadcasting signals), the number of REs available for the CREs may be N RE,C The RE available for the CRE may be referred to as RE, which may be used for the control channel. The configuration of the higher priority signals may be known to the WTRU.

[0133] The WTRU and / or base station device may define a CRE with a variable number of REs. For example, the WTRU and / or base station device may determine the number of REs for each CRE based on the RE type for the REs in the associated CRE. A CRE that includes a first type of RE may include a first number of REs (e.g., N RE,C1 A CRE that includes a second type of RE can be defined using a second number of REs (e.g., N RE,C2 ) can be defined using N RE,C1 and N RE,C2 The value of can be different and can be pre-configured and / or pre-defined. The number of REs per CRE can be determined based on the RB type. For example, the number of REs per CRE can be determined based on the RB type of the RB in which the CRE can be placed. A CRE in a first type of RB can be defined with a first number of REs. A CRE in a second type of RB can be defined with a second number of REs. The number of REs per CRE can be determined based on an index of the CRE. One or more CREs can be defined for a time cycle (e.g., TTI, subframe, radio frame). The number of REs for a CRE can be defined as a function of a CRE index. The number of REs per CRE can be determined based on the number of available REs in the RB.

[0134] A WTRU and / or a base station device may use one or more CREs. (E.g., each) CRE used by a WTRU and / or a base station device may include a set of REs that are orthogonal to each other.

[0135] The WTRU and / or base station device may use one or more CRE types. The CRE type may be determined based on the control channel type. The CRE type for a first control channel using a low latency connection may be defined and / or configured with REs located within a time symbol (e.g., within the same time symbol). The CRE type for a second control channel using narrowband transmission may be defined and / or configured with REs located within a subcarrier (e.g., within the same subcarrier).

[0136] The WTRU and / or base station device may determine the CRE type based on the RB type. For example, the CRE type may be determined based on the RB type of the configured RB for the control channel. One or more RBs may be configured for the control channel. The configured RBs may be determined as a defined RB type. The WTRU and / or base station device may determine the CRE type based on the RB type determined for the configured RB for the control channel.

[0137] The WTRU and / or base station device may determine the CRE type based on the RE type. For example, the CRE type may be determined based on the RE type of the REs that may be grouped to form a CRE. If the CRE may be defined and / or configured with REs that may be of a defined RE type, the CRE type may be determined based on the RE type of the RE associated with the CRE.

[0138] The WTRU and / or base station device may determine the CRE type based on a configuration, which may be configured via higher layer signaling and / or a broadcast channel.

[0139] The WTRU and / or base station device may determine the CRE type based on the WTRU capabilities and / or category. For example, if a WTRU (e.g., with defined WTRU capabilities and / or WTRU category) is configured to receive and / or is intended to monitor a downlink control channel, the CRE type for the downlink control channel may be determined based on the WTRU capabilities or category.

[0140] The WTRU and / or base station device may determine the CRE type based on the traffic type, which may include one or more of a service type, a higher layer signaling type, and / or a transport block type.

[0141] The WTRU and / or base station device may determine the CRE type based on the CP length used for the waveform.

[0142] The WTRU and / or base station device may determine the CRE type based on the subframe type. The subframe type may be defined and / or configured based on a traffic type provided in the subframe. For example, if a subframe is used to carry a first traffic type (e.g., low latency traffic), the subframe type may be referred to as a first subframe type (e.g., a low latency traffic subframe). Parameters for the first subframe type may be determined based on a configuration (e.g., a configuration associated with the first subframe). Parameters for each subframe type may be configured with a configuration associated with the subframe. The parameters may include one or more of a subcarrier spacing, a time symbol length, a number of subcarriers, a number of time symbols, and / or whether the subframe includes a defined broadcast signal.

[0143] Figure 8 shows examples of CRE types that are defined or configured based on RB types. For example, Figure 8 shows examples of CRE Type-A 802, CRE Type-B 804, and / or CRE Type-C 806. CRE Type-A 802, CRE Type-B 804, and / or CRE Type-C 806 can be defined or configured based on RB types.

[0144] The WTRU and / or base station device may use a single CRE type. The WTRU and / or base station device may define or predefine the CRE. For example, a certain nominal number of REs may be used for the CRE. A certain nominal number of REs may be used for the CRE regardless of RE type, control channel type, and / or WTRU capabilities (or WTRU category). The CRE may be defined and / or configured as an RE.

[0145] The WTRU and / or base station device may define and / or configure a control resource element group (CREG). For example, a control resource element group (CREG) may be defined and / or configured with a group of one or more CREs. CREG may be used interchangeably with control resource element (CCE) and / or enhanced CCE (ECCE). CREs having the same type may be grouped to form a CREG. The CREG type may be determined based on the CRE type. CREs may be grouped to form a CREG. For example, CREs may be grouped to form a CREG based on the CREG type.

[0146] The WTRU and / or base station device may define and / or use one or more CREG types. The CREG type for a downlink control information (DCI) transmission and / or a downlink control channel may be determined based on the channel type (e.g., associated channel type). For example, the CREG type used for a first channel type may be different from the CREG type used for a second channel type. The first CREG type (e.g., CREG type-A 902) may be used to carry, transmit, receive, and / or monitor DCI associated with the first channel type (e.g., a low latency channel). The second CREG type (e.g., CREG type-B 904) may be used to carry, transmit, receive, and / or monitor DCI associated with the second channel type (e.g., a narrowband transmission). A third CREG type (e.g., CREG Type-C 906) may be used to carry, transmit, receive, and / or monitor DCI associated with a third channel type (e.g., a wideband high throughput channel).

[0147] The WTRU and / or the base station device may determine a CREG type for the downlink control channel based on the transmission mode. For example, the CREG type for the downlink control channel may be determined based on a transmission mode configured for the WTRU.

[0148] The WTRU and / or base station device may define, determine, and / or configure the CREG type based on time and frequency location. For example, the CREG type may be defined, determined, and / or configured based on time and frequency location of the CREs grouped to form the CREG. FIG. 9 illustrates exemplary CREG types. The CREG types may be defined and / or configured with CREs that may be located in the same time symbol and / or may be defined in adjacent time symbols. For example, a CREG type (e.g., CREG type-A) may use low latency transmission. Downlink control channel transmission in one or more CREGs transmitted within a smaller number of time symbols may reduce transmission delay.

[0149] The WTRU and / or base station device may define and / or configure a CREG type with CREs that may be located within the same set of frequencies (e.g., the same set of subcarriers). For example, a CREG type (e.g., CREG type-B) may use downlink control channel transmission within a narrow bandwidth. Downlink control channel transmission in one or more CREGs transmitted within a smaller number of subcarriers may support narrowband transmission.

[0150] The WTRU and / or base station device may define, determine, and / or configure a CREG based on a set of REs. For example, the WTRU and / or base station device may use a pre-determined set of REs in one or more RBs. The set of REs for the CREG may be defined and / or determined based on a CREG index. The set of REs for the CREG that can be used for a first type of control channel may be located in the same time symbol and / or in adjacent time symbols. The set of REs for the CREG that can be used for a second type of control channel may be located in the same frequency. The set of REs for the CREG that can be used for a second type of control channel may be located in the same set of subcarriers and / or in adjacent subcarriers. The set of REs for the CREG that can be used for a third type of control channel may be located in multiple RBs. The multiple RBs may be of the same type of RBs.

[0151] The WTRU and / or base station device may use the reference signal to demodulate the CRE and / or the CREG. One or more reference signal structures may be used for the downlink control channel. The first reference signal structure may be a cell-specific reference signal. The cell-specific reference signal may be used for one or more downlink channels. For example, the reference signal may be used for the downlink control channel and / or the broadcast channel. The cell-specific reference signal may be transmitted over the system bandwidth. The cell-specific reference signal may be used for downlink measurements (e.g., reference signal received power). The second reference signal structure may be a dedicated reference signal. The dedicated reference signal may be used for a particular downlink channel. For example, the dedicated reference signal may be used for the downlink control channel. The dedicated reference signal may be used for a data channel. The dedicated reference signal may be transmitted within a localized resource. The dedicated reference signal may be located within a resource that may be allocated, received, and / or decoded by the WTRU.

[0152] The WTRU and / or base station device may use, define, and / or determine one or more reference signal types. For example, the reference signal type may be used, defined, and / or determined based on the time and / or frequency location of the reference signal (e.g., the reference signal pattern within a time and frequency resource grid), the scrambling sequence, the number of antenna ports, and / or the antenna port number.

[0153] The WTRU and / or base station device may determine a reference signal type for demodulating the CRE and / or CREG (and / or associated therewith). For example, the reference signal type for demodulating the CRE and / or CREG (and / or associated therewith) may be determined as a function of the CRE and / or CREG index. T A reference signal type may be used. The reference signal type may be determined as a function of the CRE index and / or the CREG index. A modulo operation may be used to determine the reference signal type. A predefined mapping rule may be used to determine the reference signal type.

[0154] The WTRU and / or base station device may determine a reference signal type associated with the CRE and / or CREG based on the CRE type and / or CREG type. For example, a first reference signal type may be used for the first CRE type (and / or CREG type). A second reference signal type may be used for the second CRE type (and / or CREG type).

[0155] The WTRU and / or base station device may use a hierarchical downlink control channel structure. The WTRU and / or base station device may use a common downlink control channel and / or one or more dedicated downlink control channels. A common DL control channel may be transmitted to and / or received by one or more WTRUs (e.g., all WTRUs) regardless of service type, traffic type, transmission type, WTRU category, and / or WTRU capabilities. A dedicated DL control channel may be transmitted to and / or received by a WTRU with a defined service type, traffic type, transmission type, WTRU category, and / or WTRU capabilities. A common DL control channel may be used interchangeably with a root DL control channel and a cell-specific control channel. A dedicated DL control channel may be used interchangeably with a service type-specific DL control channel, a transmission type-specific DL control channel, and a WTRU-specific control channel.

[0156] As shown in Figure 10, two or more layers may be used by the WTRU and / or base station device to define a hierarchical DL control channel structure. For example, a physical common downlink control channel (PCDCCH) may be used as a common DL control channel. A physical dedicated downlink control channel (PDDCCH) may be used as a dedicated DL control channel.

[0157] The WTRU may receive and / or monitor one or more DL control channels at each layer. For example, if multiple layers are used in a hierarchical DL control channel structure, the WTRU may need to receive and / or monitor one or more DL control channels at each layer. As shown in FIG. 10, the WTRU may receive and / or monitor a PCDCCH 1008 at a first layer. The first layer may be a common DL control channel, such as a physical common DL control channel 1002. The WTRU may receive and / or monitor a PDDCCH type (e.g., PDDCCH type-B 1012) at a second layer. The second layer may be a dedicated DL control channel, such as a physical dedicated DL control channel 1004. The WTRU may receive and / or monitor a PDDCCH Cat (e.g., PDDCCH Cat-A 1022) at a third layer. The third layer may be a profile, such as the L1 profile 1006. The L1 profile 1006 may include a service type and / or a PHY-QoS.

[0158] The WTRU and / or base station device can configure a dedicated DL control channel (e.g., a physical dedicated DL control channel 1004) via a broadcast channel that can be scheduled from a common DL control channel (e.g., a physical common DL control channel 1002). The PCDCCH 1008 can be used to schedule a data channel that can carry broadcasting information. The broadcasting information can include the configuration of the dedicated DL control channel. The dedicated DL control channel can be configured via WTRU-specific higher layer signaling.

[0159] The WTRU and / or base station device may define a dedicated DL control channel (e.g., each dedicated DL control channel, such as the physical dedicated DL control channel 1004) with one or more properties. The one or more properties for a dedicated DL control channel may differ according to the dedicated DL control type. These properties may include waveform, numerologies (e.g., subcarrier spacing, time symbol length, and / or guard time or cyclic prefix length), RE type (and / or RB type), CRE type (and / or CREG type), number of RBs used, duty cycle, associated reference signal, and / or control channel type.

[0160] The WTRU and / or base station device may use a common DL control channel (e.g., a physical common DL control channel 1002) to configure one or more dedicated control channels. The dedicated control channels that the WTRU receives and / or monitors may be determined based on WTRU capabilities and / or categories. The dedicated control channels that the WTRU receives and / or monitors may be determined based on service type and / or traffic type. The dedicated control channels that the WTRU receives and / or monitors may be determined based on higher layer configuration (e.g., WTRU-specific higher layer signaling). The dedicated control channels that the WTRU receives and / or monitors may be determined based on an indication. The dedicated control channels that the WTRU receives and / or monitors may be determined based on an indication from the common DL control. The WTRU and / or base station device may use the group downlink control information to indicate which dedicated control channels should be received and / or monitored (e.g., need to be received and / or monitored) for a WTRU receiving and / or monitoring the group downlink control information. The WTRU and / or base station device may determine the dedicated control channels the WTRU receives and / or monitors based on the downlink transport channel type. For example, as shown in FIG. 11, one or more downlink transport channel types (e.g., DL-SCH type-1 1006, DL-SCH type-2 1008, and / or DL-SCH type-x 1010) may be defined. The downlink transport channel types may be defined within a layer (such as the layer of the downlink transport channel 1102).One or more of the downlink transport channel types may be associated with one or more dedicated DL control channel types (e.g., PDDCCH Type-A 1112, PDDCCH Type-B 1114, and / or PDDCCH Type-X 1116). The dedicated DL control channel types may be defined within a layer (such as the layer of the downlink physical channel 1104).

[0161] The WTRU and / or base station device may use a single common downlink control channel to support all service types, WTRU categories, WTRU capabilities, and / or L1 profiles.

[0162] A nominal system bandwidth (such as nominal system bandwidth 1202 as shown in FIG. 12) may be smaller or narrower than a total system bandwidth (such as total system bandwidth 1204). For example, the nominal system bandwidth may have a bandwidth of 5 MHz and / or the total system bandwidth may have a bandwidth of 20 MHz. The nominal system bandwidth, which may be smaller or narrower than the total system bandwidth, may be defined or used as a cell for cell selection or reselection in the network. One or more cells may be used. The WTRU may determine one of the cells. The nominal system bandwidth may be defined or used for initial cell access. For example, if the WTRU has determined a cell, the WTRU may receive one or more downlink signals in the nominal system bandwidth. The one or more downlink signals may include broadcast information that may be used to access a cell, higher layer signaling for an RRC connection (e.g., WTRU-specific), one or more reference signals for measurement and / or synchronization, and / or synchronization signals for time and / or frequency synchronization. The WTRU and / or base station device may define and / or use a nominal system bandwidth for receiving or monitoring the common DL control channel.

[0163] The WTRU and / or base station device may define a nominal system bandwidth using a subset of the total system bandwidth. The WTRU and / or base station device may use frequency bands other than the nominal system bandwidth based on an indicated or received configuration from the nominal system bandwidth. A common DL control channel may be transmitted from a base station device (e.g., an eNB) and / or received by a WTRU in the nominal system bandwidth (e.g., nominal system bandwidth 1202). The WTRU and / or base station device may configure dedicated DL control channels in frequency bands within the total system bandwidth (e.g., total system bandwidth 1204). For example, a dedicated DL control channel for a control channel type (e.g., a Type-A control channel) may be placed in a frequency band (e.g., an RB) that is used and / or configured for a traffic type associated with the control channel type. A dedicated DL control channel for a traffic type (e.g., ultra-low latency) may be placed in a frequency band allocated and / or used for the traffic type. One or more dedicated DL control channels may be placed in different frequency bands that may be associated with the traffic type. The time / frequency location of the dedicated DL control channel may be predefined within a frequency band that may be configured for a traffic type and / or service type. For example, when a WTRU receives a resource configuration for a traffic type and / or service type that the WTRU may need to receive, the WTRU may know the time / frequency location of a dedicated DL control channel that may be associated with the traffic type and / or service type.

[0164] The WTRU and / or base station device may arrange the nominal system bandwidth in different frequency regions (e.g., a set of RBs, or a set of contiguous RBs). The WTRU and / or base station device may arrange the nominal system bandwidth in different frequency regions based on one or more of a service type, a traffic type, a WTRU category, and / or a WTRU capability. For example, the nominal system bandwidth for a wideband service may be arranged in a different frequency region than a frequency region for a massive MTC (mMTC) service (e.g., mMTC1212). The WTRU may find the nominal system bandwidth using a defined synchronization signal. For example, the WTRU and / or base station device may use one or more synchronization signal types. The synchronization signal type to receive may be determined based on one or more of a service type, a traffic type, a WTRU category, and / or a WTRU capability. The nominal system bandwidth (e.g., the number of RBs) may be different. For example, the nominal system bandwidth (e.g., the number of RBs) may be different based on one or more of a service type, a traffic type, a WTRU category, and / or a WTRU capability.

[0165] The WTRU and / or base station device may use an indication of the dedicated DL control channel configuration. For example, the WTRU and / or base station device may use an explicit or implicit indication of the dedicated DL control channel configuration. The explicit or implicit indication of the dedicated DL control channel configuration may be dynamic. For example, at a nominal system bandwidth, a DCI transmitted in a common DL control channel may indicate the presence of a defined dedicated DL control channel in the same time period (and / or in the same subframe, adjacent time, and / or adjacent subframe). Based on the indication, a WTRU receiving and / or monitoring a traffic type associated with the defined dedicated DL control channel may monitor and / or receive the indicated dedicated DL control channel from the DCI.

[0166] The WTRU and / or base station device may use a DCI that may use a group RNTI and / or a dedicated RNTI, for example, to indicate the presence of a defined dedicated DL control channel.

[0167] The DCI may include an identifier for the WTRU. For example, the DCI may include an identifier for the WTRU, which may be different (e.g., shorter) than the RNTI that may be used for decoding on the common DL control channel. The identifier may be included in the DCI payload of the dedicated DL control channel and / or may be used to mask a cyclic redundancy check (CRC) of the dedicated DL control channel, if present. The identifier may be or include an index to a particular resource for the dedicated DL control channel.

[0168] A WTRU and / or base station device may use a DCI for one or more dedicated DL control channels. For example, if multiple dedicated DL control channels are used, the WTRU and / or base station device may use a separate DCI for each dedicated DL control channel. The (e.g., each) dedicated DL control channel may be indicated from a group RNTI (e.g., a different group RNTI). A DCI (e.g., the same DCI) may be used for one or more (e.g., all) dedicated DL control channels. For example, a bit field in the DCI may indicate which dedicated DL control channel is indicated as having a presence. One or more WTRUs (e.g., all WTRUs) may monitor a DCI (e.g., the same DCI) in a common DL control channel. For example, one or more WTRUs may monitor the same DCI in a common DL control channel to receive an indication of a dedicated DL control channel.

[0169] The WTRU and / or base station device may use a reference signal type (and / or structure or sequence) to indicate the presence of a dedicated DL control channel. The WTRU and / or base station device may transmit the reference signal and / or sequence at a predefined (e.g., known) location. For example, if a defined dedicated DL control channel is transmitted, the reference signal and / or sequence may be transmitted at a predefined location. Otherwise, the WTRU and / or base station device may use a predefined or known location for the reference signal and / or sequence for other downlink signal transmissions.

[0170] The WTRU and / or base station device may use the subframe number, radio frame number, and / or other parameters to determine the presence of a defined dedicated DL channel. The presence of a defined dedicated DL control channel may imply that the WTRU may attempt to decode, monitor, or receive the dedicated DL control channel. For example, the presence of a defined dedicated DL control channel may imply that a WTRU associated with the dedicated DL control channel may attempt to decode, monitor, or receive the dedicated DL control channel.

[0171] The WTRU and / or base station device may use DL control channel candidates. DL control channel candidates may be used interchangeably with control channel (CC) candidates, CC decoding candidates, CC monitor candidates, and CC candidates. CC candidates may be defined and / or configured as one or more CREGs. CC candidates may carry DCI. CC candidate types may be defined or configured based on the CRE type and / or CREG type used.

[0172] The WTRU and / or base station device may use a search space. For example, a search space may be used in which one or more CC candidates may be placed. The number of CC candidates in the search space may be determined based on one or more of a service type and / or a traffic type. The service type and / or the traffic type may include ultra-low latency 1208, ultra-reliable 1210, narrowband, and wideband 1206 high throughput services. The number of CC candidates in the search space may be determined based on a WTRU capability and / or a category. The WTRU capability and / or a category may include one or more of a supportable uplink and / or downlink bandwidth, a number of carriers, a number of transmit and / or receive antennas, and / or a receive processing time. The number of CC candidates in the search space may be determined based on a time and / or a frequency resource. The time and / or a frequency resource may be configured for a control channel in which the search space is placed. For example, a configuration with larger frequency resources (e.g., RBs) may have more CC candidates compared to that of a configuration with smaller frequency resources. The WTRU and / or base station device may determine the number of CC candidates in a search space based on the associated reference signal type. For example, a search space associated with a first reference signal type may have fewer CC candidates compared to a search space associated with a second reference signal type. Reference signal type in this specification may be replaced by CRE type, CREG type, or RB type.

[0173] A search space associated with a defined service type (e.g., ultra-low latency) may include a smaller number of CC candidates (e.g., a single CC candidate). A search space associated with another service type (e.g., narrowband service) may include a larger number of CC candidates (e.g., 50 CC candidates). A search space associated with a defined service type may include CC candidates that can use the same type of CRE and / or CREG.

[0174] A WTRU may attempt to decode, monitor, and / or receive one or more (e.g., all) CC candidates in a search space. For example, a WTRU may attempt to decode, monitor, and / or receive one or more (e.g., all) CC candidates in a search space that may be associated with and / or configured for the WTRU. A WTRU may attempt to decode, monitor, and / or receive a subset of CC candidates in a search space that may be associated with and / or configured for the WTRU based on one or more of a service type (and / or traffic type), WTRU capabilities (and / or WTRU category), and / or an associated reference signal type.

[0175] A search space may be defined and / or used for a subset of downlink control channels and / or dedicated DL control channels. For example, a search space may be configured and / or used for a subset of channel types. A search space may be configured and / or used for a subset of CRE and / or CREG types. For example, a search space may be used for CREG Type-B and Type-C. A search space may be used for CREG Type-B and Type-C, while a search space may not be used for CREG Type-A.

[0176] One or more search spaces may be configured and / or used for the WTRU. The (e.g., each) search space may be associated with a defined service type and / or traffic type. Search spaces for a common DL control channel and one or more dedicated DL control channels may be configured and / or used for the WTRU. The search space for the common DL control channel (e.g., a common search space) may be located within a nominal system bandwidth. The search space for the one or more dedicated DL control channels (e.g., a dedicated search space) may be located within a frequency band. For example, the search space for the one or more dedicated DL control channels (e.g., a dedicated search space) may be located within an associated frequency band of the (e.g., each) dedicated DL control channel. The WTRU may monitor and / or attempt to decode the common search space within a subset of subframes (and / or radio frames, time frames, etc.). The WTRU may monitor and / or attempt to decode the dedicated search space within a subset of subframes (and / or radio frames, time frames, etc.). A dedicated search space may be constructed, e.g., the dedicated search space may be dynamically constructed, and an indication of the existence of the dedicated search space may be used.

[0177] A search space for a common DL control channel may be used. For example, a search space for a common DL control channel may be used for a particular service type, traffic type, WTRU category, and / or WTRU capabilities. One or more search spaces for a dedicated DL control channel may be used. For example, one or more search spaces for a dedicated DL control channel may be used for a particular service type, traffic type, WTRU category, and / or WTRU capabilities.

[0178] The WTRU and / or base station device may configure one or more search spaces. The WTRU may monitor and / or attempt to decode the configured search space. A (e.g., each) search space may include one or more CC candidates. The number of search spaces may change over time. For example, the number of search spaces may be determined based on a subframe number and / or a radio frame number. The number of search spaces may be configured via higher layer signaling.

[0179] The WTRU and / or base station device may determine the number of CC candidates for a search space based on the number of search spaces. For example, the number of CC candidates for a search space may be determined based on the number of search spaces that the WTRU may attempt to monitor and / or decode in the same subframe and / or the same time period. The number of CC candidates may be the same for the configured search spaces. For example, N S,1 When search spaces are constructed and / or used, within (e.g., each) search space, there are N CC,1 There can be N CC candidates. S,2 When search spaces are constructed and / or used, within (e.g., each) search space, there are N CC,2 There can be N CC candidates. CC,1 The number is N CC,2 can be larger than N S,1 is N S,2The number of CC candidates may be greater than 1. The number of CC candidates may be determined (e.g., independently) for each search space. The WTRU and / or base station device may vary the number of CC candidates for a search space as a function of the number of search spaces that the WTRU may attempt to monitor and / or decode in the same time period. The number of CC candidates for a common search space may be the same regardless of the number of search spaces. The number of CC candidates for a dedicated search space may be determined based on the number of search spaces in a time period.

[0180] A WTRU and / or base station device may configure a maximum number of search spaces. A WTRU and / or base station device may configure a maximum number of search spaces simultaneously and / or within the same time period. For example, the maximum number of search spaces that may be configured (e.g., simultaneously and / or within the same time period) may be determined based on one or more of a WTRU category, a WTRU capability, a service type, a traffic type, a transmission type, and / or a subframe type. For example, one or more (e.g., two) search spaces may be the maximum number of search spaces for an MTC WTRU category. A WTRU and / or base station device may use a single search space for narrowband services. A WTRU that can enable narrowband operation may support a single search space within a time period. Different search spaces may be multiplexed in time.

[0181] The WTRU and / or base station device may configure one or more search spaces. The WTRU may attempt to monitor and / or decode a subset of the configured search space. The subset of the search space that the WTRU may attempt to monitor and / or decode may be determined based on one or more of a WTRU category, a WTRU capability, a service type, a traffic type, a transmission type, and / or a subframe type. The subset may be determined based on a predefined priority rule of the search space type. A search space type may be referred to as a search space in which information related to a defined channel type may be transmitted.

[0182] The WTRU may receive one or more DCIs. For example, the WTRU may receive one or more DCIs associated with downlink transmissions in one or more search spaces. The WTRU may receive one DCI for a service type and another DCI for another service type.

[0183] The control information may be carried in the time / frequency resources used for data transmission. One or more search spaces may be configured for the WTRU. The WTRU may attempt to monitor and / or decode a selected (and / or determined) subset of the search space. The control information that may be transmitted in the non-selected (and / or non-determined) search space may be transmitted (and / or piggybacked) in a data channel associated with the control channel transmitted in the selected (and / or determined) search space. The DCI transmitted in the selected (and / or determined) search space may indicate the presence of piggybacked control information. The DCI transmitted in the selected (and / or determined) search space may indicate the time / frequency location of a data channel that may carry the piggybacked control information. The piggybacked control information may be transmitted as a DCI in the selected (and / or determined) search space. Different RNTIs may be used for the DCI in the selected search space and for the DCI carrying the piggybacked control information. If the WTRU monitors a DCI carrying piggybacked control information, the number of CC candidates may be increased. Control information associated with the selected (and / or determined) search space and the piggybacked control information may be coded (e.g., jointly coded) and / or transmitted within the DCI.

[0184] The WTRU and / or base station device may concatenate the DCI to one or more code blocks. For example, the DCI may be concatenated to one or more code blocks at the beginning or end of the code block. The DCI may be concatenated to one or more code blocks at the beginning or end of the code block of a transmission and / or may be concatenated to one or more transport blocks. The indication may be encoded together with (e.g., jointly encoded) and / or separately from the data within (e.g., each) code block and / or transport block. The indication may be used to mask a cyclic redundancy check that is added to the end of (e.g., each) code block and / or transport block.

[0185] The WTRU and / or base station device may use one or more code blocks with one or more associated DCIs. A first DCI may be associated with a first code block. The first DCI may be transmitted in a control region (e.g., DL control region). A second DCI may be associated with a second code block. The second DCI may be transmitted in a data channel (or code block) that may be scheduled by the first DCI. The (e.g., each) code block may carry data information and / or a transport block. Each code block may carry a portion of a transport block. A single HARQ-ACK may be transmitted for a transport block. One or more code blocks may be associated with a transport block. The (e.g., each) code block may include a CRC value. The first DCI that may be transmitted in the control region may include a DCI field that may be a superset of the DCI field of a subsequent DCI.

[0186] The one or more DCIs may include a WTRU identity. For example, a first DCI may include a WTRU identity. The one or more DCIs may not include a WTRU identity. For example, a subsequent DCI may not include a WTRU identity. The frequency resources of the code block may be determined and / or scheduled by the first DCI. The subsequent DCI may include and / or indicate one or more of the presence of a subsequent code block, the payload size of the subsequent code block, and / or the time resources of the subsequent code block.

[0187] The WTRU and / or base station device may use the downlink control information to schedule downlink and / or uplink data. The DCI may include one or more of a resource allocation for an associated data channel, a modulation and coding scheme, a start BTI, an end BTI, a transport block size, a HARQ process number, a new data indicator, a carrier indicator, a number of spatial layers, and / or an uplink power control field.

[0188] The WTRU and / or base station device may use a CRC for the DCI. The CRC size may be determined based on the payload size of the DCI. For example, if the DCI payload size is smaller than a predefined threshold, a first CRC size (e.g., 8 bits) may be used. If the DCI payload size is larger than a predefined threshold, a second CRC size (e.g., 16 bits) may be used. If the DCI payload size is larger than a predefined threshold, a CRC may be used for the DCI.

[0189] The size of the CRC may be determined based on one or more of a WTRU category, a WTRU capability, a service type, a traffic type, a transmission type, and / or a subframe type. The CRC size may include a value of 0, which may be considered as no CRC. A CRC size of 0 may be used for a defined service type that may use a low-latency connection (e.g., an ultra-low latency service). A CRC size of 0 may be used for a DCI within a defined search space that may include a single CC candidate. A large CRC size may be used for a defined search space that may be characterized by high reliability (e.g., an ultra-reliable transmission).

[0190] The WTRU and / or base station device may use an indication (e.g., a start indication, a stop indication, etc.) to start and / or stop repeated transmission of a data channel. For example, a transmission mode and / or scheme may use transmission (e.g., repeated transmission) of an uplink and / or downlink data transmission. The associated DCI may include an indication of start and / or stop of repeated transmission. When the WTRU receives an indication of start and / or stop of repeated transmission, the WTRU may start and / or stop transmitting and / or receiving repetitive signal transmissions. For example, when the WTRU receives a start indication, the WTRU may start transmitting and / or receiving repetitive signal transmissions until the WTRU receives a stop indication. The start and stop indications may be used for DCIs associated with a defined service type (e.g., ultra-reliable service).

[0191] To implement a flexible radio access communication system, one or more search spaces may be configured for a WTRU. The WTRU may report associated channel status information for the configured search spaces. The WTRU may report received signal power levels of (e.g., each) configured search space. The WTRU may report a search space that may have the highest received signal power level. For example, the WTRU may report a preferred search space that may have the highest received signal power level. The WTRU may report a preferred CC candidate index within the search space.

[0192] The WTRU may report its capability for downlink control channel processing time to implement a flexible radio access communication system. For example, the WTRU may report the processing time of (e.g., each) downlink control channel type. Based on the reported processing time, a timing relationship between the control channel and the data channel may be determined. A timing relationship between the control channel and the HARQ-ACK may be determined.

[0193] The processes and / or methods described herein may be applied in any combination and may be applied to other wireless technologies and for other services.

[0194] The WTRU may refer to a user's identity, such as a physical device identity or a subscription-related identity (e.g., MSISDN, SIP URI, etc.). The WTRU may refer to an application-based identity. For example, the WTRU may refer to a username that can be used per application.

[0195] The processes described above may be implemented in computer programs, software, and / or firmware embodied in computer-readable media executed by a computer and / or processor. Examples of computer-readable media include, without limitation, electronic signals (transmitted over wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, without limitation, magnetic media, magneto-optical media, such as, but not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks and removable disks, and / or optical media, such as CD-ROM disks and / or digital versatile disks (DVDs). A processor in conjunction with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, and / or any host computer. [Industrial Applicability]

[0196] The present invention can be used in wireless systems.

Claims

1. A network element associated with a base station, comprising: transmitting a first downlink control channel transmission associated with a first bandwidth region, the first bandwidth region being (1) a subset of a system bandwidth and (2) used by a wireless transmit / receive unit (WTRU) when initially accessing the network element; (1) a second downlink control channel transmission associated with a second bandwidth region of the system bandwidth; and (2) transmitting configuration information related to a set of search spaces associated with the second bandwidth region, the configuration information indicating either: a first subcarrier spacing associated with the first bandwidth region is different from a second subcarrier spacing associated with the second bandwidth region; a first set of search spaces associated with the first bandwidth region is different from a second set of search spaces associated with the second bandwidth region; or a first cyclic prefix associated with the first bandwidth region is different from a second cyclic prefix associated with the second bandwidth region; Transmitting the second downlink control channel transmission within the second bandwidth region. A transmitter configured as follows: A network element comprising:

2. The network element of claim 1 , wherein the configuration information related to the second downlink control channel transmission is associated with one of a waveform, a value, a resource element type, a resource block type, or a control channel type.

3. The network element of claim 2 , wherein the value includes any of a subcarrier spacing, a time symbol length, or a cyclic prefix.

4. The network element of claim 1 , further configured to transmit an indication in the first downlink control channel transmission.

5. 2. The network element of claim 1, wherein each of the first and second bandwidth regions is associated with a respective set of contiguous physical resource blocks.

6. 2. The network element of claim 1, wherein the first downlink control channel transmission is a common control channel transmission and the second downlink control channel transmission is a dedicated control channel transmission.

7. The network element of claim 1 , wherein the configuration information indicates a time and frequency location of the second downlink control channel transmission associated with the second bandwidth region.

8. 2. The network element of claim 1, wherein the first bandwidth region and the second bandwidth region are each associated with a different numerical value.

9. The network element of claim 1 , wherein the configuration information is transmitted using radio resource control signaling.

10. 1. A method implemented by a network element associated with a base station, comprising: transmitting a first downlink control channel transmission associated with a first bandwidth region, the first bandwidth region (1) being a subset of a system bandwidth and (2) being used by a wireless transmit / receive unit (WTRU) when initially accessing the network element; (1) transmitting a second downlink control channel transmission associated with a second bandwidth region of the system bandwidth; and (2) transmitting configuration information related to a set of search spaces associated with the second bandwidth region, the configuration information indicating either: a first subcarrier spacing associated with the first bandwidth region is different from a second subcarrier spacing associated with the second bandwidth region; a first set of search spaces associated with the first bandwidth region is different from a second set of search spaces associated with the second bandwidth region; or a first cyclic prefix associated with the first bandwidth region is different from a second cyclic prefix associated with the second bandwidth region; transmitting the second downlink control channel transmission within the second bandwidth region; A method for providing the above.

11. The method of claim 10 , wherein the configuration information related to the second downlink control channel transmission is associated with one of a waveform, a value, a resource element type, a resource block type, or a control channel type.

12. The method of claim 11 , wherein the value includes one of a subcarrier spacing, a time symbol length, or a cyclic prefix.

13. The method of claim 10 , wherein each of the first bandwidth region and the second bandwidth region is associated with a respective set of contiguous physical resource blocks.

14. 11. The method of claim 10, wherein the first downlink control channel transmission is a common control channel transmission and the second downlink control channel transmission is a dedicated control channel transmission.

15. The method of claim 10 , wherein the configuration information indicates a time and frequency location of the second downlink control channel transmission associated with the second bandwidth region.

16. The method of claim 10 , wherein the first bandwidth region and the second bandwidth region are each associated with a different numerical value.

17. The method of claim 10, wherein the configuration information is transmitted using radio resource control signaling.

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