Transmission and reception of physical downlink control channels

Abstract

A Wireless Transmit / Receive Unit (WTRU) can receive PDCCH transmissions containing CCEs mapped to one or more REGs based on a CCE-to-REG mapping. The WTRU can receive CCE-to-REG mappings indicating REG bundles corresponding to the CCEs, and can use these mappings to identify REGs for that WTRU. Depending on whether the CCE-to-REG mapping is interleaved or non-interleaved, it can be based on different parameters. If the CCE-to-REG mapping is interleaved, it can be based on the index associated with the CCE and the number of REGs in the REG bundle. If the CCE-to-REG mapping is non-interleaved, it can be based on the index of the CCE.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880009823.7, entitled “Transmission and Reception of Physical Downlink Control Channel”, filed on February 2, 2018, the contents of which are incorporated herein by reference.

[0002] Cross-references

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 454,635, filed February 3, 2017; U.S. Provisional Application No. 62 / 474,924, filed March 22, 2017; U.S. Provisional Application No. 62 / 501,001, filed May 3, 2017; U.S. Provisional Application No. 62 / 519,262, filed June 14, 2017; U.S. Provisional Application No. 62 / 543,100, filed August 9, 2017; U.S. Provisional Application No. 62 / 555,742, filed September 8, 2017; and U.S. Provisional Application No. 62 / 565,646, filed September 29, 2017, the contents of which are hereby incorporated by reference in their entirety. Background Art

[0004] In Long Term Evolution (LTE), the Physical Downlink Control Channel (PDCCH) is for the downlink control channel. To address some of the deficiencies of the PDCCH, the downlink control channel of LTE-Advanced uses the Enhanced PDCCH (E-DPCCH). The E-DPCCH divides resources between data and control by using frequency division multiplexing (FDM). In the frequency tone assigned to the control channel, the E-DPCCH can cover the entire subframe (not just the first three or four orthogonal frequency division multiplexing (OFDM) symbols). Summary of the invention

[0005] A wireless transmit / receive unit (WTRU) may receive a PDCCH transmission comprising control channel elements (CCEs) mapped to one or more resource element groups (REGs) based on a CCE to REG mapping. The WTRU may receive a CCE to REG mapping indicating a REG bundle corresponding to a CCE and may use the CCE to REG mapping to identify a REG for the WTRU. The CCE to REG mapping may be based on different parameters depending on whether the CCE to REG mapping is interleaved or non-interleaved. If the CCE to REG mapping is interleaved, the CCE to REG mapping may be based on an index associated with the CCE and the number of REGs in the REG bundle. If the CCE to REG mapping is non-interleaved, the CCE to REG mapping may be based on an index of the CCE.

[0006] A network node may determine the CCE to REG mapping. The network node may identify a control resource set. The control resource set may include one or more REGs. These REGs may be bundled in one or more REG bundles. The network node may determine which nodes and how many REGs will be included in one or more REG bundles based on the number of REGs in the REG bundle and the number of REGs in the control resource set. The network node may assemble the REG bundle based on the determination. Using the REG bundle, the network node may determine the CCE to REG mapping. Depending on whether the CCE to REG mapping is interleaved or non-interleaved, the network node may use different parameters to determine the CCE to REG mapping. If the CCE to REG mapping is interleaved, the CCE to REG mapping may be based on an index associated with the CCE and the number of REGs in the REG bundle. The CCE to REG mapping may also be based on the number of OFDM symbols in the control resource set. A high layer may configure whether the CCE to REG mapping is interleaved or non-interleaved. The interleaving may use a modular interleaver including a multiplier. The multiplier may depend on the size of the control resource set. The network node may determine CCE to PDCCH mapping using consecutive CCEs. A control resource set may include one or more OFDM symbols. The same interleaver may be used for one or more OFDM symbols, or different OFDM symbols may use different interleavers. The network node may use CCE to REG mapping to send PDCCH transmissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0008] Figure 1B is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system is shown.

[0009] Figure 1C is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system is shown.

[0010] Figure 1D is a diagram showing that according to one embodiment, Figure 1A A system diagram of another exemplary RAN and another exemplary CN used within a communication system is shown.

[0011] Figure 2An example mapping of resource element groups (REGs) to orthogonal frequency division multiplexing (OFDM) symbols of resource blocks (RBs) is shown.

[0012] Figure 3 Examples of two scenarios regarding the Demodulation Reference Signal (DMRS) location inside REGs are shown. DMRS can be located inside all REGs or a subset of REGs.

[0013] Figure 4 An example of mapping of control channel elements (CCEs) to REGs is shown.

[0014] Figure 5 Examples of mapping of frequency-first REGs to CCEs and time-first CCEs to candidates are shown.

[0015] Figure 6 An example of time-first REG-to-CCE mapping for localized and hybrid CCEs is shown.

[0016] Figure 7 An exemplary reference signal (RS) arrangement depending on the physical resource block (PRB) number is shown.

[0017] Fig. 8A and 8B An exemplary REG bundling is shown.

[0018] Fig. 9 An example hierarchy of physical downlink control channel (PDCCH) candidates with different aggregation levels corresponding to a particular WTRU is shown.

[0019] Fig.10 An example interleaver design based on sub-block interleaving is shown.

[0020] Fig.11A An example of overlapping control resource sets (CORESETs) is shown.

[0021] Fig. 11B An example of a two-stage search space using virtual indexes for lower aggregation levels is shown.

[0022] Fig. 11C An example of a two-stage search space performing the first stage for the two highest aggregation levels is shown.

[0023] Fig.12 Illustrative locations of sets of control resources or control regions in time and frequency are shown.

[0024] Fig.13 Example sizes of the control region in terms of the number of OFDM symbols are shown.

[0025] Fig.14 An example set of control resources having different durations is shown.

[0026] Fig.15 An exemplary cross-frequency scheduling process is shown.

[0027] Fig.16 An example hybrid New Radio (NR) Physical Downlink Control Channel (NR-PDCCH) resource mapping is shown.

[0028] Fig.17 An example organized NR-PDCCH resource mapping is shown. DETAILED DESCRIPTION

[0029] Detailed implementations of illustrative embodiments will now be described with reference to the various drawings. Although this description provides detailed examples of possible implementations, it should be noted that these details are intended to be illustrative and not to limit the scope of the present application.

[0030] Figure 1A 1 is a diagram showing an exemplary 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 multiple wireless users to access such content by sharing system resources including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-sOFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC), etc.

[0031] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, although it should be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network components. Each WTRU 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, any of the WTRUs 102a, 102b, 102c, 102d may be referred to as a “station” and / or “STA”, which may be configured to transmit and / or receive wireless signals, and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices working in an industrial and / or automated process chain environment), consumer electronic devices, and devices working on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a UE.

[0032] The communication system 100 may also include a base station 114a and / or a base station 114b. Each base station 114a, 114b may be any type of device configured to facilitate access to one or more communication networks (e.g., CN 106 / 115, Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of the WTRUs 102a, 102b, 102c, 102d. For example, the base stations 114a, 114b may be base transceiver stations (BTS), node Bs, e-node Bs, home node Bs, home e-node Bs, gNBs, NR node Bs, site controllers, access points (APs), and wireless routers, among others. Although each base station 114a, 114b is described as a single component, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network components.

[0033] The base station 114a may be part of the RAN 104 / 113, and the RAN may also include other base stations and / or network components (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies called cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a specific geographic area that is relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, a 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, that is, each transceiver corresponds to a sector of the cell. In one embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, by using beamforming, signals may be transmitted and / or received in a desired spatial direction.

[0034] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0035] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA, among others. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0036] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may utilize a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may utilize Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro) to establish the air interface 116.

[0037] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using new radio (NR).

[0038] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access (e.g., using dual connectivity (DC) principles). Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0039] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, 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), among others.

[0040] Figure 1AThe base station 114b in the example may be a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may use any appropriate RAT to facilitate wireless connectivity in a local area, such as a business location, a residence, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may establish a wireless local area network (WLAN) by implementing a radio technology such as IEEE 802.11. In one embodiment, the base station 114b and the WTRUs 102c, 102d may establish a wireless personal area network (WPAN) by implementing a radio technology such as IEEE 802.15. In another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell by using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, and the like). Figure 1A As shown, the base station 114b may be directly connected to the Internet 110. Thus, the base station 114b does not need to access the Internet 110 via the CN 106 / 115.

[0041] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calls, Internet connectivity, video distribution, etc., and / or may perform advanced security functions such as user authentication. Although in Figure 1A Although not shown, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT or a different RAT as the RAN 104 / 113. For example, in addition to being connected to the RAN 104 / 113 employing NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0042] The CN 106 / 115 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 that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer network devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet Protocol Suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, wherein the one or more RANs may use the same RAT or a different RAT as the RAN 104 / 113.

[0043] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication 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). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0044] Figure 1B is a system diagram showing an example WTRU 102. Figure 1B As shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a numeric keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It should be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0045] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 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 Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, however it should be appreciated that the processor 118 and the transceiver 120 may also be integrated into one electronic component or chip.

[0046] The transmit / receive component 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive component 122 may be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, the transmit / receive component 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive component 122 may be configured to transmit and / or receive RF and light signals. It should be appreciated that the transmit / receive component 122 may be configured to transmit and / or receive any combination of wireless signals.

[0047] Although in Figure 1B 102 as a single component, but the WTRU 102 may include any number of transmit / receive components 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive components 122 (e.g., multiple antennas) for transmitting and receiving radio signals over the air interface 116.

[0048] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive component 122 and to demodulate signals received by the transmit / receive component 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers that allow the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0049] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a numeric keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may receive user input data from these components. The processor 118 may also output user data to the speaker / microphone 124, the numeric keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store information in any suitable memory such as a non-removable memory 130 and / or a removable memory 132. 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, for example, on a server or a home computer (not shown).

[0050] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power for use by other components in 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 cell batteries (e.g., nickel-cadmium (Ni-Cd), nickel-zinc (Ni-Zn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0051] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) related to the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be appreciated that the WTRU 102 may acquire location information via any suitable positioning method while remaining consistent with an embodiment.

[0052] The processor 118 may also be coupled to other peripheral devices 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 peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Modules, frequency modulation (FM) radio units, digital music players, media players, video game console modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, and activity trackers, etc. The peripherals 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors, geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0053] The WTRU 102 may include a full-duplex radio for which transmission or reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 that reduces and / or substantially eliminates self-interference by means of hardware (e.g., chokes) or by signal processing by a processor (e.g., a separate processor (not shown) or by the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0054] Figure 1C 1 is a system diagram showing the RAN 104 and the CN 106 according to one embodiment. As described above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c using an E-UTRA radio technology over the air interface 116. In addition, the RAN 104 may also communicate with the CN 106.

[0055] The RAN 104 may include eNode-Bs 160a, 160b, 160c, however it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. Each of the eNode-Bs 160a, 160b, 160c may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 140a may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a.

[0056] Each eNodeB 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0057] Figure 1C The illustrated CN 106 may include a mobility management gateway (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing components is described as being part of the CN 106, it should be appreciated that any of these components may be owned and / or operated by an entity other than the CN operator.

[0058] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, performing bearer activation / deactivation processing, selecting a particular serving gateway during an initial attach 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 and / or WCDMA.

[0059] The SGW 164 may be connected to each eNode-B 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may also perform other functions, such as anchoring the user plane during inter-eNB handovers, triggering paging processing when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the contexts of the WTRUs 102a, 102b, 102c, and the like.

[0060] The SGW 164 may be connected to the PGW 146, 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.

[0061] The CN 106 may facilitate communications with other networks. For example, the CN 106 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 CN 106 may include or be in communication with an IP gateway, such as an IP Multimedia Subsystem (IMS) server, and the IP gateway may serve as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0062] Although in Figures 1A-1D Although the WTRU is described as a wireless terminal, it should be appreciated that in certain typical embodiments, such a terminal may use a (eg, temporary or permanent) wired communication interface with a communication network.

[0063] In a typical embodiment, the other network 112 may be a WLAN.

[0064] A WLAN using an architecture-based basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may access or be connected to a distributed system (DS) or other types of wired / wireless networks that send traffic into and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may arrive through the AP and be delivered to the STA. Traffic originating from the STA and destined for a destination outside the BSS may be sent to the AP for delivery to the corresponding destination. Traffic between STAs within the BSS may be sent through the AP, for example, the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. The point-to-point traffic may be sent using a direct link establishment (DLS) between the source and destination STAs (e.g., directly between them). In certain typical embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS)). For example, a WLAN using an independent BSS (IBSS) mode does not have an AP, and STAs (eg, all STAs) within or using the IBSS can communicate directly with each other. Here, the IBSS communication mode may sometimes be referred to as an "ad hoc" communication mode.

[0065] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit a beacon on a fixed channel (e.g., a primary channel). The primary channel may have a fixed width (e.g., a bandwidth of 20 MHz) or a width that is dynamically set with the aid of signaling. The primary channel may be a working channel of the BSS and may be used by STAs to establish a connection with the AP. In certain typical embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) (e.g., in an 802.11 system) may be implemented. For CSMA / CA, STAs (e.g., each STA) including the AP may sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, the particular STA may back off. In a given BSS, one STA (e.g., only one station) may transmit at any given time.

[0066] A high throughput (HT) STA may communicate using a 40 MHz wide channel (eg, by combining a 20 MHz wide primary channel with a 20 MHz wide adjacent or non-adjacent channel to form a 40 MHz wide channel).

[0067] Very high throughput (VHT) STA can support channels with widths of 20MHz, 40MHz, 80MHz and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels or by combining two discontinuous 80MHz channels (this combination can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data can be transmitted and passed through a segment parser, which can separate the data into two streams. Inverse fast Fourier transform (IFFT) processing and time domain processing can be performed separately on each stream. The stream can be mapped on two 80MHz channels, and the data can be transmitted by the STA performing the transmission. At the receiver of the STA performing the reception, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the medium access control (MAC).

[0068] 802.11af and 802.11ah support sub-1 GHz operating modes. Compared with 802.11n and 802.11ac, the channel operating bandwidth and carrier used in 802.11af and 802.11ah are reduced. 802.11af supports 5MHz, 10MHz and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz and 16MHz bandwidths using non-TVWS spectrum. According to typical embodiments, 802.11ah can support instrument type control / machine type communication (e.g., MTC devices in macro coverage areas). MTC devices can have certain capabilities, such as limited capabilities including support (e.g., only support) certain and / or limited bandwidths. MTC devices can include a battery, and the battery life of the battery is above a threshold (as an example, thereby maintaining a very long battery life).

[0069] For a WLAN system that can support multiple channels and channel bandwidths (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah), the WLAN system includes a channel that can be designated as a primary channel. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by a certain STA, where the STA originates from all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes, for STAs (e.g., MTC-type devices) that support (e.g., only support) 1MHz mode, the width of the primary channel can be 1MHz. Carrier sensing and / or network allocation vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy (e.g., because a STA (which only supports the 1MHz operating mode) transmits to the AP), then even if most of the frequency band remains space and is available for use, the entire available frequency band can be considered busy.

[0070] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. Depending on the country code, the total bandwidth available for 802.11ah is 6MHz to 26MHz.

[0071] Figure 1D 1 is a system diagram showing the RAN 113 and the CN 115 according to one embodiment. As described above, the RAN 113 may communicate with the WTRUs 102a, 102b, 102c using NR radio technology over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0072] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. Each of the gNBs 180a, 180b, 180c may include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may use beamforming processing to transmit and / or receive signals to and / or from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 160a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit a plurality of component carriers (not shown) to the WTRU 102a. A subset of these component carriers may be on an unlicensed spectrum while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and gNB 180b (and / or gNB 180c).

[0073] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with the scalable parameter configurations. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may be different for different transmissions, different cells, and / or different portions of the radio transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., containing different numbers of OFDM symbols and / or lasting different absolute time lengths).

[0074] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRU 102a, 102b, 102c may communicate / connect to the gNB 180a, 180b, 180c while communicating / connecting to another RAN (e.g., the eNode-B 160a, 160b, 160c). For example, the WTRU 102a, 102b, 102c may communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c in a substantially simultaneous manner by implementing the DC principle. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput to serve the WTRU 102a, 102b, 102c.

[0075] Each gNB 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, implement dual connectivity, implement interworking between NR and E-UTRA, route user plane data to user plane functions (UPFs) 184a, 184b, and route control plane information to access and mobility management functions (AMFs) 182a, 182b, and the like. Figure 1D As shown, gNBs 180a, 180b, and 180c can communicate with each other through the Xn interface.

[0076] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and may include a data network (DN) 185a, 185b. Although each of the aforementioned components is described as part of the CN 115, it should be understood that any of these components may be owned and / or operated by entities other than the CN operator.

[0077] The AMF 182a, 182b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, terminating NAS signaling, and mobility management, etc. The AMF 182a, 1823b may use network slicing processing to customize the CN support provided to the WTRU 102a, 102b, 102c based on the type of service being used by the WTRU 102a, 102b, 102c. As an example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) using other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0078] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and may configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0079] The UPF 184a, 184b can be connected to one or more gNBs 180a, 180b, 180c in the CN 113 via the N3 interface, which can provide the WTRU 102a, 102b, 102c with a packet-switched network (e.g., the Internet 110) to facilitate communication between the WTRU 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-host PDU sessions, processing user plane QoS, buffering downlink packets, and providing mobility anchor processing, etc.

[0080] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the CN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local data network (DN) 185a, 185b via an N3 interface connected to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b and through the UPF 184a, 184b.

[0081] In view of Figures 1A-1D and about Figures 1A-1D In accordance with the corresponding description of the present invention, one or more or all functions described herein in comparison with one or more of the following may be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a-b, DN185ab and / or any other one or more devices described herein. These simulation devices may be one or more devices configured to simulate one or more or all functions herein. For example, these simulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0082] The simulation device can be designed to implement one or more tests on other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices can perform one or more or all functions while being implemented and / or deployed as part of a wired and / or wireless communication network in whole or in part to test other devices within the communication network. The one or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to other devices to perform the test, and / or can use over-the-air wireless communication to perform the test.

[0083] The one or more simulation devices can perform one or more functions, including all functions, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test lab and / or a test scenario of a wired and / or wireless communication network that is not deployed (e.g., tested) to implement tests on one or more components. The one or more simulation devices can be test devices. The simulation device can transmit and / or receive data using direct RF coupling and / or wireless communication with the aid of RF circuits (which can include one or more antennas, for example).

[0084] A wireless transmit / receive unit (WTRU) may receive a PDCCH transmission comprising control channel elements (CCEs) mapped to one or more resource element groups (REGs) based on a CCE to REG mapping. The WTRU may receive a CCE to REG mapping indicating a REG bundle corresponding to the CCE and may use the CCE to REG mapping to identify the REG for the WTRU. The CCE to REG mapping may be based on different parameters depending on whether the CCE to REG mapping is interleaved or non-interleaved. If the CCE to REG mapping is interleaved, the CCE to REG mapping may be based on an index associated with the CCE and the number of REGs in the REG bundle. If the CCE to REG mapping is non-interleaved, the CCE to REG mapping may be based on an index of the CCE.

[0085] A network node may determine a CCE to REG mapping. The network node may identify a control resource set. The control resource set may include one or more REGs. These REGs may be bundled in one or more REG bundles. The network node may determine which REGs and how many REGs are to be included in one or more REG bundles based on the number of REGs in the REG bundle and the number of REGs in the control resource set. The network node may assemble the REG bundle based on the determination. By using the REG bundle, the network node may determine the CCE to REG mapping. Depending on whether the CCE to REG mapping is interleaved or non-interleaved, the network node may use different parameters to determine the CCE to REG mapping. If the CCE to REG mapping is interleaved, the CCE to REG mapping may be based on an index associated with the CCE and the number of REGs in the REG bundle. The CCE to REG mapping may also be based on the number of OFDM symbols in the control resource set. A high level may configure whether the CCE to REG mapping is interleaved or non-interleaved. The interleaving may use a modulo interleaver including a multiplier. The multiplier may depend on the size of the control resource set. The network node may determine CCE to PDCCH mapping using consecutive CCEs. A control resource set may include one or more OFDM symbols. The same interleaver may be used for one or more OFDM symbols, or different OFDM symbols may use different interleavers. The network node may use CCE to REG mapping to send PDCCH transmissions.

[0086] Reference symbols may include symbols that are fixed, known, and used as pilots, such as complex numbers. One or more reference signals may be used to represent a time domain signal generated after processing one or more reference symbols. For example, in orthogonal frequency division multiplexing (OFDM), a reference symbol may be a complex number fed to an inverse discrete Fourier transform (IDFT) block. One or more reference signals may be the output of an IDFT block. One or more resource elements (REs) may include OFDM symbols on a subcarrier, and a resource element group (REG) may include a RE group, which may be used as a building block for assigning resource elements to a control channel element (CCE) of a user. NR-REG, NR-CCE, and NR-PDCCH may refer to REGs, CCEs, and physical downlink control channels (PDCCHs) of a new radio (NR). NR may include radio technologies deployed in 5G and / or higher versions. However, the techniques described herein may also be applied to radio technologies deployed before 5G. Moreover, WTRU and user may be used interchangeably here.

[0087] Downlink control information (DCI) may be sent via a set of communication resources (e.g., a PDCCH). A WTRU may be associated with a set of one or more NR-PDCCH candidates. A PDCCH candidate may be a PDCCH that can be scheduled to a WTRU by a gNodeB. The WTRU may or may be configured to monitor PDCCH candidates for possible PDCCH transmissions. The set of NR-PDCCH candidates assigned to the WTRU may be associated with a search space. The search space corresponding to the WTRU may be determined by a radio network temporary identifier (RNTI) or by other mechanisms that may identify a WTRU within a cell or distinguish the WTRU from other WTRUs. The process of selecting a candidate from the candidates in the search space may be performed by an eNodeB / gNodeB. PDCCH candidates may include CCEs. CCEs may include multiple REGs. The PDCCH used here may refer to NR-PDCCH.

[0088] Figure 2 An example mapping of REGs to OFDM symbols of a resource block (RB) is shown. An NR-REG may include a set of REs. As an example, a REG may be or may include a set of corresponding OFDM symbols at a frequency tone of an RB. Figure 2 As shown, REG may be a set of the first OFDM symbol of RB. REG may be a set of the second symbol of RB.

[0089] A REG may or may not contain a reference signal (RS) or a demodulation reference signal (DMRS). If a REG does not contain resources for DMRS and contains only control information, then the DMRS in other REGs of the PDCCH may be used as a reference signal or a demodulation reference signal. Figure 3 2 shows two examples of DMRS positions within REGs. The positions of DMRS within corresponding REGs may be the same or different between different REGs. For example, the DMRS position may depend on the OFDM symbol corresponding to the REG (e.g., Figure 3 ). The DMRS location may depend on the RNTI or cell ID of the WTRU.

[0090] Figure 3An example of two cases regarding the location of DMRS within a REG is shown. The DMRS may be located within all REGs or within a subset of REGs. If multiple antenna ports are used for transmission of the PDCCH, then the DMRS corresponding to the WTRU may be divided into subsets, where each subset corresponds to an antenna port of the gNodeB. For example, if two antenna ports are used for PDCCH transmission on the gNodeB, then the resource elements reserved for DMRS may be divided into two subsets. As an example, Figure 3 As shown, DMRS symbols (e.g., consecutive DMRS symbols) may alternate between antenna ports. Figure 3 In the embodiment, every other DMRS resource element may be included in one of the two subsets corresponding to the two antenna ports.

[0091] For multiple (eg, two) REGs that are adjacent in time, RS aggregation may be used. RS aggregation may use one or more (eg, all) DMRSs in two REGs together, for example, to improve channel estimation quality.

[0092] NR-CCE can be mapped to REG. Figure 4 An example of mapping CCE to REG is shown. As shown, a CCE may include multiple REGs. As an example, Figure 4 As shown, these CCEs can have a fixed number of REGs (e.g., 4). The REGs of a CCE can be either locally allocated (e.g., adjacent in time or frequency) or distributed. The REGs of a CCE can be on the same OFDM symbol or on different OFDM symbols. Figure 4 An example is shown in FIG. 1 , where the REG of CCE1 is on the first OFDM symbol of the slot and the REG of CCE2 is on the second OFDM symbol.

[0093] Each PDCCH candidate may include one or more CCEs. The processing of mapping REGs to CCEs and mapping CCEs to PDCCH candidates may include various options. For example, the processing of mapping REGs to CCEs may be local, distributed, or a mixture of local and distributed. Following the time-first REG to CCE mapping may be time-first CCE to PDCCH candidate mapping or frequency-first CCE to PDCCH candidate mapping. Following the frequency-first REG to CCE mapping may be time-first CCE to PDCCH candidate mapping or frequency-first CCE to PDCCH candidate mapping. Various options for REG to CCE and CCE to candidate mapping processing may include one or more of the following illustrative options shown in Table 1.

[0094] Table 1: Example options for REG to CCE and CCE to candidate mapping

[0095]

[0096] Time-first REG to CCE mapping and time-first CCE to candidate mapping may include first assigning REG to one or more CCE in time. REG may be assigned to one or more CCE located in different OFDM symbols and the same frequency modulation. These CCEs may be assigned to one or more PDCCH candidates in time. For example, these CCEs may be assigned to one or more PDCCH candidates located in different OFDM symbols and the same frequency modulation. These CCEs may be assigned to different frequency modulations (e.g., after the available OFDM symbols are exhausted). Time-first REG to CCE mapping and time-first CCE to candidate mapping may not be feasible in practice. For example, after REG is assigned to CCE, the available symbols in the control region will be filled.

[0097] Time-first REG to CCE mapping and frequency-first CCE to candidate mapping may include first assigning REGs to one or more CCEs in time. These REGs may be assigned to one or more CCEs located on different OFDM symbols and the same frequency modulation. One or more REGs may be assigned to different frequency modulations (e.g., after running out of available OFDM symbols). These CCEs may be assigned to one or more PDCCH candidates on different frequency modulations. Time-first REG to CCE mapping and frequency-first CCE to candidate mapping may have two options: only local mapping of REG to CCE, or both local and non-local (e.g., distributed or mixed) REG to CCE mapping. For example, mixed REG to CCE mapping may include local REG pairing with distribution or local mapping for CCE. REGs adjacent in time and / or frequency may be assigned to one CCE for use in local and / or distributed candidates. REGs with or without RS may be in CCE.

[0098] The frequency-first REG to CCE mapping and the time-first CCE to candidate mapping may include first assigning the REG to one or more CCEs in frequency. The REG may be assigned to one or more CCEs in the same OFDM symbol and different frequency modulations. The one or more CCEs may be assigned to one or more PDCCH candidates in different OFDM symbols and the same frequency modulation. The frequency-first REG to CCE mapping and the time-first CCE to candidate mapping may have different variations. For example, the frequency-first REG to CCE mapping and the time-first CCE to candidate mapping may only include local mapping of REG to CCE. As another example, the frequency-first REG to CCE mapping and the time-first CCE to candidate mapping may include both local and distributed mapping of REG to CCE, and local and mixed mapping of REG to CCE. In the frequency-first REG to CCE mapping and the time-first CCE to candidate mapping, the CCE may be located on a symbol spanning one or more PRBs. RS aggregation processing can be performed on different CCEs of the same PDCCH candidate in the time domain. CCEs belonging to the same candidate and adjacent in time can assist RS aggregation.

[0099] The frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may include first assigning the REG to one or more CCEs in frequency. The REG may be assigned to one or more CCEs in the same OFDM symbol and different frequency modulations. The one or more CCEs may be assigned to one or more PDCCH candidates in the same OFDM symbol and different frequency modulations. The frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may have different variations. For example, the frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may include local mapping of REG to CCE. As another example, the frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may include local and distributed mapping or local and mixed mapping of REG to CCE. The frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may not include RS aggregation. The frequency-first REG to CCE mapping and the frequency-first CCE to candidate mapping may be used with beam switching.

[0100] In frequency-first REG to CCE and frequency-first CCE to candidate mapping, REGs on the same corresponding symbol of different PRBs may be mapped to (e.g., one) CCE. In frequency-first REG to CCE and frequency-first CCE to candidate mapping, one or more CCEs on the same corresponding symbol (e.g., all CCEs on the first symbol in a time slot or all CCEs on the second symbol in a time slot) may be grouped to form a PDCCH candidate. In frequency-first REG to CCE and frequency-first CCE to candidate mapping, RS aggregation may not be implemented in time. In frequency-first REG to CCE and frequency-first CCE to candidate mapping, beam switching is possible.

[0101] Figure 5 An example of mapping frequency-first REG to CCE and time-first CCE to candidate is shown. Figure 5 As shown, {CCE1, CCE2} or {CCE3, CCE4} can be a PDCCH candidate with aggregation level 2. {CCE1, CCE2, CCE3, CCE4} can be a PDCCH candidate with aggregation level 4. In the frequency-first REG to CCE and time-first CCE to candidate mapping, REGs on the same OFDM symbol (and different PRBs) can be mapped to CCEs (related examples are as follows Figure 5 In the frequency-first REG-to-CCE and time-first CCE-to-candidate mapping, RS aggregation (eg, for improving the quality of channel estimation) may be performed together with CCE aggregation.

[0102] In time-first REG-to-CCE and frequency-first CCE-to-candidate mapping, temporally adjacent REGs may be assigned to CCEs (e.g., for localized and distributed candidates). Distributed PDCCH candidates may have a distributed mapping of CCEs to one or more PDCCH candidates using localized REG-to-CCE mapping or mixed REG-to-CCE mapping (e.g., localized in time and distributed in frequency).

[0103] Figure 6 An example of time-first REG-to-CCE mapping for localized and hybrid CCEs is shown. Figure 6In the example shown, each CCE can contain two REG pairs, each of which is adjacent in time. In the REG to CCE mapping based on REG pairing and hybrid local-distributed mapping, each CCE can be divided into REG pairs that are adjacent in time. Channel estimation for each REG pairing can be performed together (e.g., to improve the quality of channel estimation). REG pairings can be a mixture of REGs with and without RS. REG pairings can have REGs with different RS densities.

[0104] Figure 7 An exemplary RS arrangement depending on the PRB number is shown. The location of the REG with RS (or DMRS) may depend on the PRB number. The location of the REG without RS (or DMRS) may depend on the PRB number. For example, if the PRB number is odd, the RS may be located on the first REG of the REG pairing. If the PRB number is even, the RS may be located on the second REG of the REG pairing. The RS arrangement may depend on the PRB number for localized and distributed PDCCH candidates.

[0105] One or more REGs may be assembled (eg, bound) into a REG bundle. Fig. 8A and 8B An exemplary REG bundling is shown. Fig. 8A An exemplary bundling of REGs over time is shown. Figure 8B An example bundling of REGs over frequency is shown. Fig. 8A and 8B As shown, the illustrated REG bundling process may be performed for one or more distributed CCEs of size 6 in time or frequency. As an example, the size of a CCE may include the number of REGs in the CCE. Fig. 8A As shown, REG0, REG1, REG8, REG9, REG16, and REG17 may be included in the distributed CCE. Figure 8B As shown, REG0, REG1, REG4, REG5, REG8 and REG9 may be included in the distributed CCE.

[0106] A REG bundle may include multiple REGs (e.g., the size of the REG bundle). Two or more REGs that are adjacent in time and / or frequency may be bundled together. Fig. 8A and 8B As shown, two REGs that are adjacent in time and / or frequency can be bundled together. Fig. 8A In , REG16 and REG17, which are adjacent in time, are bundled together. Figure 8B In the example, REG8 and REG9, which are adjacent in frequency, are bundled together.

[0107] When two or more REGs (e.g., adjacent REGs) are bundled together, the corresponding channel estimation of the two or more REGs can be performed together. For the REGs in the REG bundle, it is assumed that the precoders are the same. For example, the precoders for REG0 and REG1 can be the same (for example, Fig. 8A and 8B As shown). One or more (e.g., some or all) REGs in a REG bundle may include DMRS. In an example, REGs with DMRS (e.g., all REGs with DMRS) may have the same DMRS density. As an example, REGs with DMRS (e.g., all REGs with DMRS) may have a DMRS density of 1 / 3 or 1 / 4. For a DMRS density of 1 / 3, DMRS may be used for 1 / 3 of the resource elements (REs) in the REG. In an example, if each REG has 12 REs, then 1 / 3 of the 12 REs (i.e., 4 REs in each REG) may use DMRS.

[0108] The REG bundling in a control resource set (CORESET) may be similar. For example, the REG bundling in a CORESET may have the same number of REGs and / or similar REG bundling mappings. The REG bundling mappings for the REG bundling in a CORESET may be (e.g., all) time-first or frequency-first.

[0109] The mapping of REGs to CCEs may be the same for a CORESET (eg, the entire CORESET).

[0110] The size of a REG bundle or the REG bundle size may describe the number of REGs in the REG bundle. For example, the size of a REG bundle may be 2, 3, or 6, corresponding to a REG bundle having 2, 3, or 6 REGs. A REG bundle (e.g., a REG bundle size and type) may be configured to control a resource set. For example, a REG bundle size of 6 may be used for a localized PDCCH (e.g., non-interleaved REG to CCE mapping). A REG bundle size of 2 or 3 may be used for a distributed PDCCH (e.g., interleaved REG to CCE mapping). The REG bundle size may be configured per CORESET (e.g., the REG bundle size for a particular CORESET may be based on the size of the particular CORESET).

[0111] The REG bundling mapping for REG bundling in a CORESET may be based on the configuration of the CORESET (e.g., the size of the CORESET). The size of the CORESET may include the number of OFDM symbols in the CORESET. When the CORESET covers one (e.g., only one) OFDM symbol, the REG bundling in the CORESET may be frequency-bound (e.g., frequency-first). For example, REGs that are adjacent in frequency may be bundled together. When the CORESET spans multiple OFDM symbols (e.g., 2 or 3), the REG bundling in the CORESET may be time-first REG bundling or frequency-first REG bundling. By using frequency-first REG bundling processing (e.g., for a CORESET spanning multiple symbols), PDCCH candidates may be present across multiple beams. For REG bundling whose bundling size is equal to the CORESET size (e.g., the length of the CORESET in time) or a multiple thereof, the time-first REG bundling processing may be used (e.g., preferred). With time-first REG bundling, placing the DMRS in one or more REGs on the first OFDM symbol in the bundle may allow channel estimation to be performed (eg, by a receiver entity) for the entire REG bundle.

[0112] REG bundling may be of one of the following types. REG bundlings in a CORESET may be of the same type. For example, each REG bundling in a CORESET may be of the same type. For a REG bundling of size 2 and bundled in time, the first REG may have one or more DMRS, and the second REG may or may not have one or more DMRS. For a REG bundling of size 3 bundled in time, the first REG may have one or more DMRS, and the second and / or third REG may or may not have one or more DMRS. For a REG bundling of size 2 bundled in frequency, (e.g., all) REGs in the REG bundling may have one or more DMRS. For a REG bundling of size 3 bundled in frequency, (e.g., all) REGs in the REG bundling may have one or more DMRS. For a REG bundling of size 6 bundled in frequency, (e.g., all) REGs in the REG bundling may have one or more DMRS. For a REG bundle of size 6 and bundled in a rectangular arrangement of 2 REGs bundled in frequency and 3 REGs bundled in time, the 2 REGs on the first OFDM symbol may have one or more DMRS, and the other REGs in the REG bundle may or may not have one or more DMRS. For a REG bundle of size 6 and bundled in a rectangular arrangement of 3 REGs bundled in frequency and 2 REGs bundled in time, the 3 REGs on the first OFDM symbol may have one or more DMRS, and the other REGs in the REG bundle may or may not have one or more DMRS.

[0113] One or more of REG, REG bundle and CCE may be mapped. In one example, REG, REG bundle and CCE may be mapped, where each CCE includes 6 REGs and each REG bundle includes 2 REGs. The number of REGs within the control resource set may be N. REG or Here we use It can represent a floor function. If N CCE is the number of CCEs in the control resource set, and N bundle To control the number of REG bundles in a resource collection, you can use the function Determine the number N of CCEs in the control resource set CCE (The relevant example is shown in Equation 1), and controls the number N of REG bundles in the resource set bundle You can use the function To determine (a related example is shown in Equation 2). As an example, the following equation may be used.

[0114]

[0115]

[0116] The number of CCEs in a control resource set may be based on the number of REGs N within the control resource set. REG and the number N of REGs in a CCE CCE,REG is determined (the relevant example is shown in Equation 3). The number N of REG bundles in the control resource set bundle The number N of REGs within the control resource set can be based on REG and the number N of REGs in the REG bundle bundle,REG The number N of REG bundles in a CCE is determined (the relevant example is shown in Equation 4). CCE,bundle It can be based on the number N of REGs in a CCE CCE,REG and the number N of REGs in the REG bundle bundle,REG to determine (a related example is shown in Equation 5).

[0117]

[0118]

[0119]

[0120] The number of REGs (e.g., REGs in a REG bundle) within a control resource set may be based on N REG to number (for example, from 0 to N REG -1). As an example, when the control resource set covers multiple OFDM symbols, the REGs may be numbered first in time (e.g., in a continuous manner) and then in frequency (e.g., in a continuous manner). When the control resource set covers one (e.g., only one) OFDM symbol, then the REGs may be numbered from 0 to N. REG -1 numbers the REGs (eg, consecutively in frequency).

[0121] REG bundling can be based on the number N of REG bundles in the control resource set. bundle to number (for example, from 0 to N bundle -1). CCE can be based on the number N of CCEs in the control resource set CCE to number (for example, from 0 to N CCE -1).

[0122] REGs can be based on the index and the number N of REGs in the REG bundle. bundle,REG For example, the number is N bundle,REGk、N bundle,REG k+1, ..., N bundle,REG k+N bundle,REG The REGs numbered -1 may form a REG bundle with index k. In one example, the REGs numbered 2k and 2k+1 may form a REG bundle with index k.

[0123] The PDCCH may use different transmission modes, such as local or distributed transmission. Local transmission and distributed transmission may be associated with different mappings of CCE to REG and / or CCE to REG bundling. Local transmission may correspond to non-interleaved mapping of CCE to REG and / or CCE to REG bundling. Distributed transmission may correspond to interleaved mapping of CCE to REG and / or CCE to REG bundling. For example, the PDCCH controls resource set X. m One or more PDCCH candidates (eg, all PDCCH candidates) in the PDCCH may use only local transmission or only distributed transmission. m It can represent the mth CORESET. The transmission mode used by PDCCH can be configured by the higher layer.

[0124] Within a control resource set, the mapping of CCEs to REGs may be based on one or more REG bundles in the control resource set and / or the size of the CORESET. The size of the CORESET may include the number N of REG bundles in the control resource set. bundle REG bundling can be based on the number N of REG bundles in a CCE CCE,bundle Come numbered.

[0125] For example, for local mapping (eg, non-interleaved REG to CCE mapping), a CCE numbered n may correspond to a CCE numbered nN within a control resource set. CCE,bundle +j REG bundle, where j = 0, 1, ..., N CCE,bundle For distributed mapping (e.g., interleaved REG to CCE mapping), a CCE numbered n may correspond to a CCE numbered (nN) within a control resource set. CCE,bundle +j)d mod N bundle REG bundle, where j = 0, 1, ..., N CCE,bundle -1, and d may be an integer used for interleaving and / or permutation in the distribution mapping. Although the function xd mod N is used in the above example bundle , but other functions f(x) can also be used for the interleaving process.

[0126] NR-PDCCH candidates may be mapped to CCEs. PDCCH candidates may include one or more CCEs. The number of CCEs in a PDCCH candidate may be referred to as an aggregation level. The number of CCEs in a PDCCH candidate may be a number in a set of positive integers (e.g., {1, 2, 4, 8, 16}). PDCCH candidates in a search space (e.g., corresponding to a WTRU) may have different or similar aggregation levels. The PDCCH may be selected based on the required SNR of the WTRU (e.g., between candidates within the search space) and may avoid being consistent with one or more PDCCHs selected for other WTRUs. The PDCCH may be selected by a gNodeB and / or another entity.

[0127] Fig. 9 An example hierarchical structure for PDCCH candidates with different aggregation levels corresponding to a particular WTRU is shown. The PDCCH candidates corresponding to a particular WTRU may have a hierarchical or semi-hierarchical structure, whereby a PDCCH candidate with a larger aggregation level may include all or some CCEs corresponding to a PDCCH candidate with a smaller aggregation level (e.g., Fig. 9 As shown in Fig. 9 As shown, 902 may be a CCE group including CCEs 910, 912, 914, 916, 918, 920, 922, 924 and other CCEs. CCEs 910, 912, 914, 916, 918, 920, 922, 924 may be in positions or sequences 4, 8, 5, 9, 10, 11, 6, and 7. In CCE group 902, a PDCCH candidate with an aggregation level of 1 may include CCE 910. Another PDCCH candidate with an aggregation level of 1 may include CCE 912. A PDCCH candidate with an aggregation level of 2 may include CCEs 910 and 914. Another PDCCH candidate with an aggregation level of 2 may include CCEs 912 and 916. A PDCCH candidate with an aggregation level of 4 may include CCEs 912, 916, 918, and 920. PDCCH candidates 908 with aggregation level 8 may include CCEs 910 , 914 , 922 , 924 , 912 , 916 , 918 , and 920 .

[0128] PDCCH candidates may be mapped to CCEs and / or REGs so that the REGs included in the PDCCH candidates may be associated with the same OFDM symbol. For example, a PDCCH candidate may only include REGs that are on the same OFDM symbol. The WTRU may receive information about an OFDM symbol corresponding to a PDCCH associated with the WTRU and may search for the PDCCH based on the received information. If the WTRU receives information about an OFDM symbol corresponding to a PDCCH associated with the WTRU, the WTRU may reduce the effective search space for the WTRU (as an example, by performing this process, the WTRU may reduce the blind detection complexity of the PDCCH). This information may be transmitted using a common physical control channel (e.g., a common PDCCH) and / or other mechanisms.

[0129] For both interleaved and non-interleaved scenarios, PDCCH candidates may be mapped to CCEs. For localized PDCCHs (e.g., corresponding to non-interleaved scenarios), adjacent CCEs may be assigned to the PDCCHs. For distributed PDCCHs (e.g., corresponding to interleaved scenarios), CCEs may be dispersed in the CORESETs.

[0130] The mapping of local and distributed CCEs to PDCCH candidates can be based on REG bundling. According to the mapping of REG bundling to CCE (for example, for the case of interleaved and non-interleaved REG bundling), local and distributed CCEs can be mapped to PDCCH candidates. For example, CCEs with consecutive numbers can be assigned to PDCCH. If the mapping of REG bundling to CCE is non-interleaved, adjacent REG bundles with consecutive numbers can be mapped to CCE. CCEs with consecutive indexes (for example, CCEs with indexes j and j+1) can become adjacent to each other. By assigning CCEs with consecutive numbers, local (for example, non-interleaved) PDCCH candidates can be generated. If the mapping of REG bundling to CCE is interleaved, then consecutive CCEs (for example, CCEs with consecutive indexes) will not be adjacent to each other and / or far away from each other. If there are 6 REGs on each CCE, the mapping of CCE to PDCCH candidates described here can be based on the following content.

[0131] In an example where a CCE has 6 REGs (e.g., as described herein), the process of mapping REGs to CCEs may include one or more of the following. REG bundling may be defined based on an index and / or REG bundling size. A CCE may include a REG bundling determined based on the number of REGs in the corresponding REG bundle and the CCE index. For example, CCEj may include a REG bundle {f(i), (f(i+1)), …, f(i+6 / N bundle,REG-1)}. For the process of mapping REGs to CCEs in a non-interleaved manner, f{x}=x. x can be the index of the REG bundle (e.g., REG bundle i). f{.} is the interleaver, where, as an example, for the process of mapping REGs to CCEs in an interleaved manner, i=6j / N bundle,REG . N bundle,REG It can be the number of REGs in a REG bundle, and similar to L, it can be the REG bundle size.

[0132] As an example, based on whether interleaved processing or non-interleaved processing is used, CCEs with numbers (e.g., indexed or identified) can be adjacent to each other or non-adjacent to each other. For example, if non-interleaved mapping (e.g., non-interleaved mapping of REG to CCE) is used, then the last REG bundle of CCE1 and the first REG bundle of CCE2 will be adjacent. If interleaved mapping of REG to CCE is used, then the last REG bundle of CCE1 and the first REG bundle of CCE2 will be far away from each other. The "CCE to REG mapping" and "REG to CCE mapping" used here can be used interchangeably, and the mapping can be constructed using a combination of "REG to bundle mapping" (as an example, it can be called "bundle to REG mapping") and "bundle to CCE mapping" (as an example, it can be called "CCE to bundle mapping").

[0133] One or more distributed PDCCHs may include and / or use a combination of multiple interleavers. For example, one or more distributed PDCCHs may include and / or use two different interleavers, such as f(x) and g(x), where f(x) may permute the index of the REG bundle (e.g., for mapping to CCE), and g(x) may permute the index of the CCE (e.g., for mapping to PDCCH candidates).

[0134] The interleaver for REG bundling can be a (e.g., any) general function f(x) that maps an index of a REG bundle to another index. As an example, the function f(x) can map a logical REG bundle index to a physical REG bundle index. The interleaver can include one or more of the following properties (e.g., to support a well-distributed PDCCH design). For one or more (e.g., all) aggregation levels, the interleaving function can spread the REG bundles of PDCCH candidates across the CORESETs. As an example, for one or more non-contiguous CORESETs, the interleaving function can ensure that the REG bundles of PDCCH candidates are properly (e.g., well) distributed across the frequency components of the CORSETs.

[0135] The interleaver function may be designed based on a modulo operation (e.g., a modulo interleaver). For example, the interleaving function f(x) may map an index x to f(x)=d,x mod N, where d and N are natural numbers associated with the CORESET. N may be a modulo base, and d may be a multiplier. As an example, the modulo base N may be Nbundle, which may be the number of REG bundles in the CORESET. The multiplier d may be selected such that the overall modulo operation promotes (e.g., ensures) good dispersion. As an example, good dispersion may include REG bundles of PDCCH candidates that are evenly distributed in different parts of the CORESET, and / or having the maximum possible distance between REG bundles of PDCCH candidates. One or more of the following may promote good dispersion. The multiplier d may be coprime with the modulo base Nbundle. As an example, the multiplier d and the modulo base Nbundle may not have any common divisor greater than 1. As an example, consecutive indices are not mapped to indices that are close to each other, thereby ensuring good dispersion even at very low aggregation levels. The multiplier d may be associated with a lower limit and / or an upper limit. For example, the multiplier d may not be too small or too large so that the multiplier d reaches the modulo base N (eg, is similar or close thereto).

[0136] The multiplier d may be specified or configured. For example, the multiplier d may be specified according to the CORESET size in units of REG bundles (e.g., the number of REG bundles Nbundle in the control resource set). The multiplier d may be indicated by a table. The multiplier d may be included (e.g., explicitly included) in the CORESET configuration.

[0137] REG bundling can be interleaved using a sub-block interleaving method. Fig.10An exemplary interleaver design based on sub-block interleaving is shown. Sub-block interleaving can be an iterative method, which includes one or more of the following (e.g., 1, 2, and 3), as examples. Sub-block interleaving can start with a row with Nbundle REG bundles (as an example, Nbundle can be the number of REG bundles in the control resource set). The k×Bl matrix can be transformed (e.g., for each iteration) into a Bk×l matrix. B can be the sub-block size. K can be the number of rows, and Bl can be the number of blocks of the matrix before one iteration. As an example, the transformation can be achieved by arranging kxl sub-matrices of the Bkxl matrix in a column (as an example, instead of a row). The conversion can be performed in an iterative manner. If this type of iteration is no longer possible (e.g., when the final matrix has only one column), the result can include a column of size Nbundle. This column of size Nbundle can include a mapping of logical REG bundles to physical REG bundles (e.g., a final mapping). The logical index of the REG bundle can be based on the mapping of the REG bundle to the CCE. The physical index of the REG bundle can be based on one or more physical locations of the REG bundle in the CORESET. In each iteration, B can change or remain unchanged. For example, B can be different for each iteration of sub-block interleaving. For sub-block interleaving, B can be constant (e.g., remain the same for all iterations). Fig.10 As shown in the example of , for mapping of PDCCH candidates with AL={1,2,4,8} to a CORESET containing 32 REG bundles, when B=2, the interleaver may be based on sub-block interleaving. REG bundling may be associated with a REG bundling size of three REGs.

[0138] like Fig.10As shown, logical REG bundles (e.g., an initial 32 REG bundles) can be mapped to physical (e.g., 32 physical) REG bundles (e.g., located at 4). After 4, regardless of the aggregation level of PDCCH candidates, each PDCCH candidate is well distributed over the frequency components of the CORESET (e.g., evenly distributed over different frequency parts of the CORESET and / or having the maximum possible distance between the REG bundles of the PDCCH candidates). In this example, assume that one PDCCH candidate has an AL of size 2, one PDCCH candidate has an AL of size 4, one PDCCH candidate has an AL of size 8, and two PDCCH candidates have an AL of size 1. For the PDCCH candidate with AL = 8, the REG bundle can include {1, 9, 5, 13, 3, 11, 7, 15, 2, 10, 6, 14, 4, 12, 8, 16}. For the PDCCH candidate with AL = 4, the REG bundle can include {17, 21, 19, 23, 18, 22, 20, 24}. For the PDCCH candidate with AL = 2, the REG bundle can include {25, 27, 26, 28}. For the PDCCH candidate with AL = 1, REG bundles 29 and 30 can belong to one PDCCH candidate, and REG bundles 31 and 32 can belong to another PDCCH candidate.

[0139] If the REG bundle index is from 0 to 2 n , then sub-block interleaving can be performed by reversing n binary digits of the REG bundle index (e.g., mapping the logical REG bundle with index to the physical REG bundle with index ). Sub-block interleaving can spread (e.g., in a robust manner) the REG bundles of PDCCH candidates over the CORESET, and / or work well for multiple (e.g., all) aggregation levels. The basic sub-block interleaving design can support (e.g., only support) certain CORESET sizes, such as CORESET sizes that are powers of 2. The size of the CORESET can be measured by the number of REG bundles. The interleaving design based on sub-block interleaving can include different sub-block partition values B. The interleaving design based on sub-block interleaving can use a combination and / or cascade of sub-block interleaving and modulo operation interleaving (e.g., to make sub-block interleaving more general). A method for combining and / or cascading sub-block interleaving and modulo operation interleaving can include one or more of the following. The method can include envisioning N bundle = N2 n , where N is odd. N can be any number. The method can include mapping (e.g., each) logical REG bundle index x2 n + y (where x < N and y < 2 n ) to z2n + t, where z = d. x mod N and t can be determined by flipping the binary digits of y. x, y, n and t can be chosen arbitrarily or randomly.

[0140] The WTRU may assume that a common interleaver is used for a CORESET spanning multiple OFDM symbols over multiple (e.g., all) OFDM symbols. The common interleaver for a CORESET may be implicitly signaled. For example, when the WTRU is configured with a multi-symbol CORESET with time-first REG-to-REG bundling mapping, the WTRU may assume that a common interleaver function is used for the OFDM symbols (e.g., all OFDM symbols) included in the CORESET.

[0141] The WTRU may assume that for a CORESET spanning multiple OFDM symbols, different interleavers are used for some OFDM symbols (e.g., OFDM symbol by OFDM symbol). By using a different interleaver for each OFDM symbol, time domain precoder cycling may be enabled for PDCCH candidates. By using a different interleaver for each OFDM symbol, multi-beam operation may be enabled for PDCCH candidates in higher frequency bands. (E.g., each) OFDM symbol may be transmitted on multiple beams. The interleaving function f_i(x) for OFDM symbol i may map the index x to f_i(x) = d_i.xmodN, where d_i and N are natural numbers associated with the CORESET. N may be a modulo basis. Examples of modulo basis N may be based on N = N bundle / N ofdm_CORESET to determine, and / or may represent the number of REG bundles within an OFDM symbol of a CORESET, where N ofdm_CORESET ∈{1,2,3} may represent the number of OFDM symbols included in the CORESET. The multiplier d_i may be selected so that the total modulo operation on each OFDM symbol ensures a good distribution in frequency for the PDCCH candidates. For example, by interleaving the REG bundles included in the PDCCH candidates spanning multiple OFDM symbols, these REG bundles may be made non-adjacent in frequency.

[0142] The use of different interleavers for a CORESET may be signaled implicitly or explicitly. For example, when the WTRU is configured with a multi-symbol CORESET with frequency-first REG to REG bundling mapping, the WTRU may implicitly assume that a different interleaver function is used for each OFDM symbol contained in the CORESET. When the WTRU is configured with a multi-symbol CORESET with time-first REG to REG bundling mapping, the WTRU may implicitly assume that the same interleaver function is used for (e.g., all) OFDM symbols contained in the CORESET. The WTRU may receive an indication indicating whether the same interleaver is used on multiple OFDM symbols within a CORESET or whether different interleavers are used for different OFDM symbols contained in the CORESET. The WTRU may receive the indication explicitly in a DCI or through radio resource control (RRC) signaling (e.g., as part of the CORESET configuration).

[0143] The CORESET may be configured via a Master Information Block (MIB), a Physical Broadcast Channel (PBCH), and / or higher layer signaling (e.g., RRC). The configuration of the CORESET performed via higher layer signaling may include one or more frequency resources of the CORESET, a first OFDM symbol, a duration (e.g., in terms of the number of symbols), a mapping of CCEs to REGs (e.g., interleaved or non-interleaved), a REG bundling size (which may be signaled only for the interleaved case, as an example), one or more quasi-co-location (QCL) assumptions about antenna ports, and / or a monitoring period of the CORESET (a default period may be every slot, as an example).

[0144] One or more frequency resources may be indicated by a CORESET configuration. For example, a CORESET configuration may indicate which resource blocks (RBs) are allocated to a CORESET configuration or CORESET. A CORESET may be contiguous or non-contiguous in frequency.

[0145] Consecutive CORESETs may be within a bandwidth part. A CORESET configuration for contiguous CORESETs within a bandwidth part may indicate (e.g., specify) the first and last RBs (or PRBs, for example) of the CORESET. A CORESET configuration for contiguous CORESETs within a bandwidth part may indicate a starting RB and the length of the CORESET (e.g., in frequency). The granularity (e.g., granularity of frequency) indicated by the CORESET configuration may be in terms of RBs, resource block groups (RBGs), and / or a portion of a bandwidth part (e.g., a granularity of 1 / n the size of the bandwidth part containing the CORESET).

[0146] A discontinuous CORESET may include one or more contiguous sections. For example, each contiguous section of a discontinuous CORESET may correspond to a corresponding bandwidth section. As an example, a frequency configuration of a CORESET may include a combination of frequency configurations for each contiguous section of the CORESET (e.g., in each bandwidth section and / or as described herein).

[0147] A discontinuous CORESET may include a finite number of contiguous parts (e.g., up to 2). The finite number of contiguous parts may or may not be in different bandwidth parts. For example, the frequency configuration of a discontinuous CORESET may include (e.g., the frequency resources of a discontinuous CORESET may be indicated by) the first and last RB of the CORESET and the first and last RB of the gap between (e.g., two) contiguous parts of the CORESET.

[0148] The number of RBs within a CORESET can be configured such that the total number of REGs is a multiple of the number of REGs in a CCE (e.g., to avoid wasting control resources). For example, if each CCE has 6 REGs and the time length of the CORESET is two symbols, then the number of RBs in the CORESET can be a multiple of 6 / 2=3. If each CCE has 6 REGs and the length of the CORESET is a single symbol, then the number of RBs in the CORESET can be a multiple of 6.

[0149] Fig.11A An example of overlapping CORESETs is shown. Two or more different CORESETs may overlap on some resource elements. As shown in FIG. 11A , CORESET 1104 and CORESET 1106 may overlap on overlapping portion 1108. Depending on the number of OFDM symbols, the number of resource elements, and / or the type of REG to CCE mapping, the overlapping CORESETs may have similar or different lengths. Fig.11A As shown, two CORESETs with lengths of 1 and 2 OFDM symbols (eg, CORESET 1104 with a length of 1 OFDM symbol and CORESET 1106 with a length of 2 OFDM symbols) may overlap each other.

[0150] Different REG to CCE mappings may be defined for overlapping resources shared between different CORESETs. Each different REG to CCE mapping may correspond to each corresponding CORESET. For example, in Fig.11A, the overlapping portion 1108 may be defined with different REG to CCE mappings, where the first REG to CCE mapping corresponds to CORESET 1104 and the second REG to CCE mapping corresponds to CORESET 1106. If there are two different REG to CCE mappings for overlapping CORESETs, then multiple (e.g., two) REG bundles from different CORESETs may partially overlap in one or more REGs. Multiple REG bundles from different CORESETS may partially overlap and / or may be inconsistent with each other. Multiple (e.g., two) CCs from two different CORESETs may partially overlap and / or may be inconsistent with each other in one or more REGs. For example, if a 1-symbol CORESET with a localized frequency-first REG to CCE mapping overlaps with a 2-symbol CORESET with a distributed time-first REG to CCE mapping, then two CCEs from the two CORESETs may partially overlap on one REG.

[0151] As an example, the network may take into account the overlapping pattern of CCEs from two overlapping CORESETs to avoid assigning two overlapping PDCCH candidates at the same time (eg, to avoid collision of two overlapping PDCCH candidates). The pattern may imply how the two CCEs overlap.

[0152] For example, for the design of one or more search spaces, it is desirable to minimize the chance of partial overlap between PDCCH candidates of two overlapping CORESETs. The aggregation levels and / or positions of the PDCCH candidates of two overlapping CORESETs may be considered to minimize the number of overlapping PDCCH candidates (e.g., candidate pairs) from the two CORESETs. If there are overlapping PDCCH candidates (e.g., each overlapping pair), the overlap may be maximized for the overlapping PDCCH candidates. For example, for a 3-symbol CORESET, aggregation levels 3, 6, and 9 may be added to better match aggregation levels 1, 2, 4, and 8 for 1-symbol and 2-symbol CORESETs.

[0153] In the process of assigning PDCCH candidates and designing search space, multiple (e.g., two) PDCCH candidates from two different CORESETs are allowed to partially overlap. In this case, for example, the WTRU can use one or more overlapping known patterns in the PDCCH candidates to improve the performance of blind detection and / or PDCCH decoding.

[0154] A WTRU (e.g., each WTRU) may be assigned multiple possible PDCCH candidates, where the PDCCH candidates should be monitored to perform blind detection. The set of PDCCH candidates monitored by the UE may be referred to as a search space. The search space may be common between WTRUs (e.g., all WTRUs) in a cell. The search space may be group-common. For example, a group-common search space is common to a WTRU group. The search space may be WTRU-specific. One or more common search spaces may be used for initial access and / or for PDCCHs that carry downlink control information (DCI) (e.g., system information and / or paging). Different common search spaces may correspond to different RNTIs and / or be scrambled by different RNTIs (e.g., SI-RNTI for system information and / or pre-occupancy indication (PI)-RNTI for pre-occupancy indication). The position of a PDCCH candidate that carries certain group-common DCI (e.g., slot format indication (SFI)) within the search space may be fixed and / or may be known to the WTRU. For example, the WTRU may detect and / or decode a group-common DCI without performing (e.g., any) blind detection between PDCCH candidates contained in the search space. In one example, as an example, a search space carrying PDCCH candidates containing SFIs may have one candidate (e.g., only one candidate) as opposed to a common or WTRU-specific search space. A common or WTRU-specific search space may contain multiple PDCCH candidates.

[0155] A WTRU-specific search space (e.g., for each WTRU) may be configured by higher layer signaling (e.g., at least in the case of non-initial access). A WTRU-specific search space (e.g., configured by higher layer signaling) may indicate (e.g., specify) a set of PDCCH candidates for a DCI format size and / or aggregation level (e.g., specifying each DCI format size and each aggregation level in a CORESET). For some combinations of one or more DCI format sizes and / or one or more aggregation levels, the PDCCH candidate set may be empty. The total number of PDCCH candidates that should be monitored by the WTRU may be limited by a fixed number corresponding to the WTRU. The fixed number corresponding to the WTRU may indicate the blind decoding capability of the WTRU. WTRU-specific search spaces of multiple (e.g., two) different WTRUs may overlap (e.g., overlap on one or more PDCCH candidates). A WTRU-specific search space may overlap with a common (e.g., group-common) search space. The search space may be completely within (e.g., inside) a CORESET. A common search space may be in a CORESET configured with an interleaved REG to CCE mapping. The WTRU-specific search space may be inside a CORESET with interleaved REG to CCE mapping and / or non-interleaved REG to CCE mapping.

[0156] The WTRU-specific hierarchical and semi-hierarchical search space may be performed in multiple (e.g., two) stages. For example, a hash function may be used to indicate one or more starting positions of the PDCCH candidates for the WTRU, based on the WTRU's RNTI and the aggregation level (or levels) of the PDCCH candidates. As an example, in NR, channel estimates may be reused for PDCCH blind detection of multiple PDCCH candidates. For example, reuse of channel estimates may be facilitated by using a hierarchical (e.g., "nested") or semi-hierarchical WTRU-specific search space. One or more of the following methods, including hash functions and / or mapping methods, may be used to design a hierarchical or semi-hierarchical WTRU-specific search space: CCE mapping for a hierarchical search space in two stages or a configurable semi-hierarchical search space.

[0157] CCEs may be mapped for a two-stage hierarchical search space. PDCCH candidates with one or more highest aggregation levels may be located, and PDCCH candidates with one or more lower aggregation levels may be located within the region spanned by the PDCCH candidates with one or more highest aggregation levels. As an example, PDCCH candidates with one or more highest aggregation levels may be located before locating PDCCH candidates with one or more lower aggregation levels. A hash function (e.g., hash function #1) may indicate the index of the first CCE of a PDCCH candidate with one or more highest aggregation levels that may be assigned to the search space of the WTRU. The CCEs of a PDCCH candidate may have consecutive indices starting from a starting index. The CCEs covered by a PDCCH candidate may be enumerated with consecutive indices (e.g., virtual indices). For other aggregation levels, a second hash function (e.g., hash function #2) may be used to locate the virtual index of the first CCE of a PDCCH candidate. Fig. 11B An exemplary two-stage hierarchical search space with virtual indexes is shown. The two-stage hierarchical search space may use virtual indexes for lower aggregation levels. As shown, CORESET 1110 may include 32 CCEs, and the search space may include two candidates 1112 and 1114 with one or more highest aggregation levels (as an example, 8 in this example). 0-31 may be the initial index. The initial index of the CCE may be consecutive. The starting index of the candidate with the highest aggregation level may be selected based on a corresponding hash function. Candidate 1112 may be associated with initial indexes 8-15, and candidate 1114 may be associated with initial indexes 24-31. The starting index of candidate 1116 with the highest aggregation level may be selected based on a corresponding hash function. Candidate 1116 may be associated with indexes 0-7. Candidate 1118 may be associated with indexes 8-15.

[0158] The hash function may indicate a starting index for the candidate for the WTRU. The hash function may take as input(s) some or all of the following parameters: one or more valid corresponding control region sizes, one or more RNTIs of the WTRU, one or more aggregation levels, and / or one or more cell IDs. The hash function may depend on other additional parameters. The one or more valid corresponding control region sizes may include the number of CCEs and / or CORESET size for hash function #1 used in phase 1. Phase 1 may be used to locate PDCCH candidates with one or more highest aggregation levels.

[0159] Hash function #1 may be applied to a CORESET (e.g., the entire CORESET). Hash function #2 may be applied to a region of a CORESET (e.g., a smaller sub-region covered by PDCCH candidates with one or more highest aggregation levels). The effective CORESET size of hash function #2 may be the number of CCEs in the corresponding sub-region. For example, Fig. 11B In the example shown, the effective CORESET size for hash function #2 may be 16.

[0160] A configurable semi-hierarchical search space may also be used. A hierarchical search space may be used to reduce channel estimation overhead. One or more methods may be used to reduce the impact of blocking probability. For example, in a two-stage search space, the first stage may be performed for the k highest aggregation levels. Fig. 11C An example of a configurable semi-hierarchical search space when k=2 and the two highest aggregation levels are 8 and 4 is shown. The first stage may be for the two highest aggregation levels (8 and 4 in this example as an example). The sub-area used to locate a candidate with a lower aggregation level may be an area covered by the candidates with the two highest aggregation levels. For example, the sub-area may include a set of CCEs that may be included in at least one candidate with the two highest aggregation levels. Fig. 11C As shown, the sub-region available for candidates with lower aggregation levels (e.g., the union of 1136 and 1138) can be defined as the footprint of the five PDCCH candidates with the two highest aggregation levels, including PDCCH candidates 1126, 1128, 1130, 1132, and 1134. PDCCH candidate 1126 can include or cover CCE 8-15. PDCCH candidate 1128 can include or cover CCE 24-31. PDCCH candidate 1130 can include or cover CCE 8-11. PDCCH candidate 1132 can include or cover CCE 16-19. PDCCH candidate 1134 can include or cover CCE 28-31.

[0161] like Fig. 11CAs shown, a PDCCH candidate with a lower aggregation level can be selected by a hash function pointing to a virtual CCE index in a sub-area that can be covered by a candidate with the two highest aggregation levels. There is a trade-off between reducing the blocking probability and reducing the channel estimation overhead. For example, a smaller k can indicate more layers, and / or can result in a higher blocking probability and lower channel estimation overhead. The value K can be configurable. For example, the value of k can be selected based on the desired blocking probability and channel estimation overhead. The value of k can be selected from a set of possible values ​​(e.g., {1,2}), and the selection can be included in the CORESET configuration. For example, the highest aggregation level indication (e.g., a bit in the CORESET configuration) can indicate whether one or more corresponding search spaces are constructed by k=1 or k=2.

[0162] An indication of the end of the control region (e.g., in time) may be determined. The number of OFDM symbols used in the control region may be variable, such as 2, 3, or other positive integers. The control region may cover one or more search spaces for a group of WTRUs, and / or may be referred to as a control resource set. The end of the control region in time (e.g., the number of OFDM symbols in the control region) may be set semi-statically by a mechanism such as radio resource control (RRC), and / or may be dynamically configured and signaled to the WTRU via a common PDCCH.

[0163] Fig.12 12 shows an example location of a control resource set or control region in time and frequency. The size of the control region may be different in different parts of the system spectrum (e.g., 1208). For example, the number of OFDM symbols in the control region may be different in different RBs. In some parts of the spectrum (e.g., RBs), the number of OFDM symbols for the control channel may be zero. Fig.12 As shown, control region 1202 and control region 1204 may be located in different parts of the system spectrum and may have different sizes. RBs (e.g., 1206) may convey data (e.g., without Fig.12RBs may be grouped to convey information about the end of the control region (e.g., in time) in order to reduce the size of the information required. For example, RBs may be divided into one or more of frequency subbands, frequency blocks, or RB blocks (BRBs). For BRBs (e.g., BRBs containing 8, 16, ..., or other integer number of RBs), the size of the corresponding control portion (e.g., in terms of the number of OFDM symbols) may be indicated separately. For example, if the number of OFDM symbols in the control region is at most 3, then the information (e.g., the number of OFDM symbols in the control region, including the possibility of zero OFDM symbols for control (e.g., only data is sent)) may be sent via 2 bits. As an example, if there are a total of N RB blocks, then 2N bits may be transmitted to (e.g., may need to be transmitted to) the WTRU to indicate the location of the control region in the entire available system bandwidth. For semi-static configuration, these 2N bits may be sent via a mechanism such as RRC, and / or for dynamic configuration, these bits may be included in common downlink control information (DCI) and sent via common PDCCH.

[0164] The control region and data in DL may be frequency-domain multiplexed. Fig.13 An example location of a control resource set or control region in time and frequency is shown. A control resource set 1304 carrying a DL control channel (e.g., NR-PDCCH) may be partially mapped on one or more subbands used for control and / or data channel transmissions. One or more unused resource elements / resource element groups / control channel elements / control resource sets 1306 located at the first OFDM symbol at the beginning of a time slot may be used for data transmission. Fig.13 As shown, the PDCCH and the PDSCH may be multiplexed using FDM in the first few OFDM symbols (eg, OFDM symbol 1308), and the remaining OFDM symbols within the time slot may be multiplexed using TDM.

[0165] The WTRU may determine the starting position of downlink data in a timeslot for a specified RB or group of RBs. The determination may be based on an explicit indication as part of a WTRU-specific DL assignment (e.g., DCI) or a group-common DCI. The starting position of downlink data in a timeslot for a specified RB or group of RBs may be configured in a semi-static manner (e.g., by higher layer signaling). The WTRU may determine the starting position of DL data by assuming (e.g., implicitly) that a set (one or more) of unused control resources within the subband are used for data transmission in the timeslot. Fig.14 An example set of control resources with different durations is shown. Fig.14For the example shown, the starting position of the downlink data for the upper part of the subband may be symbol #1 (e.g., assuming that the first symbol in the time slot is symbol #0), and for the lower part of the subband, the starting position of the DL data may be symbol #0. The starting position of the downlink data for one or more designated control resource sets within the time slot may be associated with the duration of the control resource set. Fig.14 As shown, the starting position of the downlink data for control resource set #0 may be a symbol after symbol #1 (e.g., symbol #2), and the starting position of the DL data for control resource set #1 may be symbol #1. The starting position of the DL data in a timeslot may vary on the subband where the WTRU is scheduled.

[0166] Fig.15 1504. An exemplary cross-frequency scheduling is shown. The WTRU may receive multiple DL assignments within a timeslot. The DL assignments may convey scheduling information related to data transmission on OFDM symbols following one or more control resource sets. For example, a DL control resource set (e.g., PDCCH 1504) may be mapped or mapped primarily on the first few OFDM symbols in a timeslot. The PDSCH transmitted to the WTRU in the remaining OFDM symbols in the timeslot may have a longer duration (e.g., Fig.15 The unused set of control resources may be used for data transmission in an FDM manner in conjunction with the control channel and / or may (e.g., primarily) span the first few OFDM symbols in the slot. The WTRU may receive a second DL assignment within the slot, where the assignment may convey scheduling information related to data transmission on the unused set of control resources at the beginning of the slot (e.g., short PDSCH 1506).

[0167] A short PDSCH (e.g., short PDSCH 1506) may have a different channel coder, rate matching process, modulation, or precoder than a long PDSCH. For coverage-limited scenarios or where higher reliability is desired for the control channel, the REs contained in the PDCCH may be sent in a power-boosted manner (e.g., by borrowing power from REs forming the PDSCH on the same OFDM symbol). By performing transmissions in a power-boosted manner, the link budget of the PDSCH may be increased at the expense of PDSCH performance. A short PDSCH may use a lower coding rate or a more robust modulation scheme than a long PDSCH.

[0168] The granularity of one or more unused control resource sets for short PDSCH transmission may be one or more RBs in the frequency domain and / or multiple OFDM symbols at the beginning of a timeslot in the time domain. From the perspective of the gNB, multiple control resource sets may be defined to span the entire subband. From the perspective of the WTRU, the WTRU-specific and group-common search spaces may be mapped to subsets of control resource sets within the subband in the timeslot. The control resource sets in the timeslot that are not used by the gNB for DL ​​control signaling may be dynamically indicated to the WTRU as unused control resource sets. This indication may be provided using a bit mapping technique. For example, 4 control resource sets may be mapped to 4 bits so that '0' indicates an unused control resource set(s). If there is no indication from the gNodeB, then the WTRU does not assume that the resource control sets that are not used by one or more WTRU search spaces are unused resource control sets, given that control signaling for other WTRUs in the system may use a subset of the resource control sets.

[0169] If beamforming is present (e.g. for higher frequency bands), the WTRU may use channel estimates derived from reference symbols or a subset of reference symbols within the control resource set to equalize data in the 'short PDSCH' region. Reference symbols mapped to a subset of REs for a given OFDM symbol may be used by the WTRU for control and data monitoring on the same OFDM symbol.

[0170] A transmission scheme and DMRS design for NR-PDCCH can be provided. Aspects associated with NR-PDCCH may include one or more of the following: CRC attachment, coding, rate matching and symbol generation, pure frequency interleaving / scrambling, or NR-PDCCH resource element mapping. CRC attachment processing may be performed. The CRC may be calculated by considering the WTRU's identity (e.g., C-RNTI or a combination of the WTRU identity and the beam identification metric). By performing coding, rate matching and / or symbol generation, a set of REGs and CCEs may be created. Pure frequency interleaving / scrambling processing may be performed by interleaving / scrambling implemented over the full length of a set of CCEs, and / or may be performed by interleaving / scrambling implemented over the length of a single CCE or REG. For example, the interleaver / scrambler may be initialized by a combination of cell or beam identification parameters.

[0171] The overall mapping structure of the NR-PDCCH block may be associated with one or more transmission schemes (e.g., depending on the adopted transmission scheme). The gNB may transmit the NR-PDCCH in multiple ways. The gNB may transmit the NR-PDCCH block by using different transmission schemes (e.g., space-frequency block coding (SFBC) and / or precoder cycles) simultaneously. The gNB may use one or more of the same transmission schemes over the entire NR-PDCCH region. The gNB may employ the same transmission scheme with different parameter assumptions.

[0172] In an example scenario with different transmission schemes, the gNB may use SFBC transmission for one set of WTRUs (e.g., a subset thereof) and use precoder cycling for another set of WTRUs in the cell. The gNB may use SFBC transmission for one analog beam and use precoder cycling for another analog beam.

[0173] In an example scenario with the same transmission scheme, the gNB may apply a precoder cycle to the WTRUs. The precoding codebook used for one set of WTRUs (e.g., a subset thereof) may be different from another set of WTRUs in the cell. The gNB may use different codebooks for the precoder cycle used for different simulated beams.

[0174] The NR-PDCCH resource mapping may be divided into several regions (e.g., to allow efficient use of reference signals). A region may be characterized by a span associated with the region in terms of time and frequency resources. A (e.g., each) region may contain a different number of NR-PDCCH blocks, and / or a (e.g., each) NR-PDCCH block may include a different number of CCEs. A region may indicate a time-frequency span in which available reference signals may be used to perform channel estimation and demodulate the NR-PDCCH blocks mapped to the region.

[0175] Fig.16 An example hybrid NR-PDCCH resource mapping is shown. Fig.16 In the NR-PDCCH mapping, z1, z2 and z3 can represent three different regions for NR-PDCCH mapping. NR-PDCCH resources can be divided into three segments in an organized manner. Fig.17 2 shows an example of organized resource mapping for NR-PDCCH. Fig.17 As shown, three sections (eg, regions) may be defined in the order of z1, z2, and z3.

[0176] A zone may represent a span of a region that may be considered by the WTRU to extract reference signals for channel estimation and / or demodulation. For example, a zone represented by z1 may (e.g., may only) provide reference signals available in symbols over a specified frequency span. A zone represented by z3 may represent a region in which potentially available reference signals (e.g., all potentially available reference signals) across three symbols may be used to demodulate an NR-PDCCH block (e.g., all NR-PDCCH blocks mapped to the segment or zone).

[0177] One or more definitions of regions may be fixed and / or configured. For example, a region (e.g., each region) may be defined by the span size of the region in the frequency domain and / or time domain and the location of an anchor resource element. An example of an anchor resource element may be one or more first resource elements of a region. A mapping process (e.g., a hybrid or organized mapping process) may be configured in a semi-static manner or dynamically configured via L1 signaling. Hybrid resource mapping may be used in conjunction with (e.g., primarily with) dynamic configuration. Organized mapping may be used in conjunction with (e.g., primarily with) semi-static configuration.

[0178] In a fixed definition, the definition of partitions may be characterized based on the system bandwidth. Additional parameters may be provided via RRC signaling or L1 control. For example, for organized resource mapping, the order and general structure of the segments or regions may depend on the system bandwidth. The number of regions per segment may be indicated by higher layer signaling.

[0179] Information about the span and location of the area may be determined by a combination of RRC signaling and L1 control.

[0180] The common region may be defined according to system parameters (eg, permanently defined) or may be signaled to WTRUs (eg, all WTRUs) or groups of WTRUs through RRC signaling. The common region may indicate information related to the definition of a region for all or different groups of WTRUs.

[0181] In a control channel, channel estimates may be reused in multiple blind decodings. For a common or group control channel, a single estimate is common to the WTRUs in the group. DMRS may be used across resource sets. One or more of the following may be used. The RS may include a non-precoded DMRS that supports an open-loop transmission scheme, such as spatial transmit diversity (e.g., STBC or SFBC) or a precoder cycle for reliability. The RS may be a non-precoded DMRS that supports a closed-loop transmission scheme, such as closed-loop precoding. The precoding matrix indicator (PMI) to be used may be signaled. In a group common control channel, the PMI may be the same for some (e.g., all) WTRUs in the group. For example, a group may be created from WTRUs that support similar PMIs. The RS may be a precoded DMRS that supports a closed-loop transmission scheme, such as closed-loop precoding. The closed-loop transmission scheme may be used with a single WTRU assigned to a control resource or a group of WTRUs assigned the same PMI. For one or more transmissions above 6 GHz, beam pairing may be used for control channel transmissions, such as to facilitate sufficient link margin for control channel transmissions. The beam reference signal may be used by the control channel for the WTRUs within the beam (e.g., all WTRUs). An open loop or semi-open loop transmission scheme may be used for control information transmission. Hybrid precoded RS (e.g., as in sub-6 GHz transmission) may also be used, where both the BRS and the control information are modified through a combination of analog and digital beams.

[0182] NR-PDCCH search space restrictions can be dynamically configured. Here, DL control channel search space, NR-PDCCH search space, NR-PDCCH WTRU dedicated search space, NR-PDCCH common search space, NR-PDCCH group common search space, composite search space and search space can be used interchangeably.

[0183] The WTRU may monitor, receive and / or attempt to decode NR-PDCCH candidates in the search space. The NR-PDCCH candidates may carry downlink control information (DCI).

[0184] The WTRU may monitor or attempt to decode all NR-PDCCH candidates or a subset thereof in a WTRU-specific search space. In one example, if the WTRU monitors a subset of NR-PDCCH candidates in a WTRU-specific search space, the subset of NR-PDCCH candidates may be determined, selected, and / or configured with the aid of a WTRU-specific configuration based on the WTRU-ID and / or WTRU-specific parameters. The WTRU-ID may include one (e.g., at least one) or more of a C-RNTI or IMSI. The WTRU-specific parameters may include one (e.g., at least one) or more of a beam ID, a beam pairing link ID, a transmit beam ID, a configured transmission mode, or a WTRU capability. In one example, if the WTRU monitors a subset of NR-PDCCH candidates in a WTRU-specific search space, the subset of NR-PDCCH candidates may be dynamically indicated. The WTRU may be instructed to monitor all NR-PDCCH candidates or a subset thereof. For example, the WTRU may be configured to monitor (e.g., all) NR-PDCCH candidates in a WTRU-specific search space. The WTRU may be configured to monitor a subset of NR-PDCCH candidates.

[0185] The set or subset of NR-PDCCH candidates for the group common search space may be determined based on the group ID and / or group-specific parameters, and / or configured with the aid of a group-specific configuration. The group ID may be a group-specific RNTI that may be configured via higher layer signaling. The group ID may be determined based on the service type of the WTRU. For example, a first group ID may be associated with a first service type (e.g., eMBB), and a second group ID may be associated with a second service type (e.g., URLLC). One or more group-specific parameters may include one (e.g., at least one) or more of a WTRU category, a WTRU capability, a service type, a transmission mode, a coverage level, or an operating mode.

[0186] In the search space, the WTRU may monitor one or more NR-PDCCH candidates. One or more NR-PDCCH candidates may carry downlink control information (DCI). The search space may be configured, determined and / or transmitted in (e.g., each) time slot or time slot subset. In the following, time slots may be used interchangeably with mini-time slots, subframes, radio frames, and TTIs. One or more of the following may apply. One (e.g., at least one) or more search spaces may be configured for the WTRU in a scheduling time interval (STI). The scheduling time interval may include one (e.g., at least one) or more of a TTI, time slot, subframe, radio frame, or mini-time slot. One or more search space types may be configured in the STI. The search space type may include one (e.g., at least one) or more of a WTRU-specific search space, a group common search space, or a common search space. The WTRU may monitor or may be configured to monitor one or more search space types within the STI. One or more search space types may be located in the same control channel resource, or in different control channel resources (one or more). The WTRU may receive an indication of one or more types of search spaces monitored in the STI. The number of NR-PDCCH candidates in the search space is determined based on one (e.g., at least one) or more of a TTI index, a slot index, a subframe index, and / or a micro-slot index. The number of NR-PDCCH candidates in the search space may be determined based on the number of OFDM symbols used, configured, and / or determined for the search space. For example, if the number of OFDM symbols used for the first search space is greater than the number of OFDM symbols used for the second search space, then the number of NR-PDCCH candidates used for the first search space may be greater than the number of NR-PDCCH candidates used for the second search space. The number of NR-PDCCH candidates (one or more) in the search space monitored in a slot may be greater than the number of candidates in a micro-slot.

[0187] For NR-PDCCH, a component search space may be used, determined and / or defined for it. One or more NR-PDCCH candidates may be monitored within the component search space. The NR-PDCCH candidates in the component search space may include a subset of NR-PDCCH candidates located in a search space (e.g., a composite search space), wherein the search space may be associated with one or more component search spaces. One or more of the following may apply. The component search space may be located in N (e.g., N≥1) consecutive OFDM symbols within a control channel resource. The control resource may be a time and / or frequency resource used or configured for NR-PDCCH. The control channel resources for the WTRU-specific search space may be configured in a WTRU-specific manner, and the control channel resources for the group-common search space may be configured in a group-specific manner. One or more NR-PDCCH candidates in the component search space may be located in the same N consecutive OFDM symbols. The composite search space may include one or more component search spaces. The WTRU may monitor one (e.g., at least one) or more component search spaces in the composite search space. The WTRU may be instructed, configured and / or determined to monitor one or more component search spaces within the composite search space. The one or more component search spaces may be multiplexed in non-overlapping or partially overlapping time resources (e.g., OFDM symbols) within the control channel resources. At least one component search space may be determined based on one or more of: WTRU-specific parameters including a WTRU-ID, a DCI type that can be monitored by the WTRU, a time slot or subframe number in which the component search space is located, and / or a cell ID (e.g., a virtual cell ID). One or more time resources (e.g., OFDM symbols) may be associated with one or more component search spaces. The WTRU may be determined to monitor the NR-PDCCH at least one time resource. The one or more time resources may be determined based on one or more of the WTRU-specific parameters, the DCI type, the time slot or subframe number, and / or the cell ID. The composite search space may be configured with the aid of higher layer signaling. The set of component search spaces that the WTRU monitors within the composite search space may be indicated in a dynamic manner. An indication may be signaled in (e.g., each) STI to indicate the component search space that the WTRU is to monitor. The number of component search spaces for the composite search space in the STI may be determined based on the number of OFDM symbols used for the composite search space in the STI. For example, if K OFDM symbols are used for a composite search space in an STI, then K component search spaces may be used, determined and / or configured in the STI. The number of OFDM symbols used for the composite search space may also be dynamically determined and / or indicated in (e.g., each) STI.

[0188] The mapping of CCEs to REGs may be determined based on the number of component search spaces that the WTRU monitors. For example, if the WTRU is configured or determined to monitor (e.g., all) component search spaces in a search space, then the set of REGs that form a CCE may be located in one or more different OFDM symbols. If the WTRU is configured or determined to monitor a subset of the component search spaces, then the set of REGs that form a CCE may be located in the same OFDM symbol. One or more of the following may apply.

[0189] A REG may be a set of consecutive resource elements (REs) located in the same OFDM symbol. The number of these consecutive REs may be predetermined, fixed and / or configured.

[0190] A CCE may include a set of REGs that are within a control channel resource, and the mapping of CCEs to REGs may be considered as which set of REGs is used to form the CCE. One or more CCE types may be used. A first CCE type may be based on a set of REGs that are located in the same OFDM symbol, and a second CCE type may be based on a set of REGs that are located in multiple OFDM symbols. When the WTRU is configured to monitor all component search spaces or all NR-PDCCH candidates in the search space, the first CCE type may be used. When the WTRU is configured to monitor a subset of component search spaces or a subset of NR-PDCCH candidates in the search space, the second CCE type may be used.

[0191] Whether to monitor all NR-PDCCH candidates or a subset of NR-PDCCH candidates in the search space can be determined based on one or more of: a time slot index, a subframe index, a radio frame index and / or a micro-time slot index, system parameters including a cell ID or a virtual cell ID, WTRU-specific parameters including a WTRU-ID and / or at least one of the configured transmission modes, the type of time slot, subframe, radio frame and / or micro-time slot, and / or service type (e.g., eMBB, URLLC, mMTC).

[0192] The PDDCH may be shared between (e.g., all) WTRUs in a cell or in a group of WTRUs. Downlink control information (e.g., group-common DCI) may be shared in a group. The content of the group-common DCI may include a slot format. The slot format may indicate whether the slot is for DL ​​heavy, UL heavy, all DL, all UL, or "other". The "other" may include blank slots or future scenarios that will be defined later (e.g., currently reserved for forward compatibility purposes).

[0193] A group-common DCI (which may also be referred to as a common DCI) may allow for signaling to narrow the search space of a WTRU. For example, the signaling may indicate the OFDM symbol(s) that may be used by the corresponding WTRU-specific PDCCH. As an example, as described herein, a group-common DCI may signal the end of a control region in time.

[0194] WTRU groups may be formed in one or more of the following ways. WTRUs may be grouped according to WTRU categories or capabilities. WTRUs may be grouped according to geography. As an example, WTRUs with limited coverage and which may require uplink transmissions using a DFT-S-OFDM-based waveform may be assigned to one group. WTRUs with unrestricted coverage and which may use a CP-OFDM waveform to perform UL transmissions may be assigned to another group. WTRUs may be grouped according to beam access. For example, WTRUs that request access using a specific beam pairing (e.g., a specific beam pairing set) may be grouped together. WTRUs may be grouped according to one or more transmission schemes. For example, WTRUs that use (e.g., require) a multi-layer transmit diversity scheme or WTRUs that are in multiple total radiated power (TRP) transmissions and connected to a specific TRP set may be grouped together. WTRUs that can be served in MU-MIMO (e.g., UL / DL) transmissions at the same time may be set into a group.

[0195] A WTRU may belong to more than one group.

[0196] These groups may be established statically at initial access, semi-statically via RRC signaling, and / or dynamically via L1 / L2 signaling. For example, an L1 group DCI signal may be used to send a group identifier and / or add or remove a WTRU from a group.

[0197] Based on the composition of the group, a specific RS may be allocated for the group common PDCCH. In a group with WTRUs widely distributed across cells, the RS may be a non-precoded DMRS in combination with a transmit diversity based transmission scheme (e.g., space or frequency based diversity) for reliability purposes. In a group with WTRUs located within a certain spatial region (e.g., a beam or a specific PMI), a precoded DMRS may be used in combination with a precoder selected in such a way that the precoder provides sufficient performance for all member WTRUs. A closed loop transmission scheme may then be used. Non-precoded DMRS with additional PMI signaling may be used with a closed loop transmission scheme.

[0198] The search space for the group common PDCCH may be monitored by (e.g., all) WTRUs in the group. A portion (one or more portions) of the group common search space may overlap with a WTRU specific search space (one or more). The search space may be located within (e.g., completely within) a control resource set (CoReSet). Multiple control resource sets may overlap in time and / or frequency. A CoReSet with a common search space may be determined (e.g., obtained) from the MIB and / or system information. A CoReSet with a common search space may be determined (e.g., implicitly derived) using initial access information. A CoReSet with additional group common and / or WTRU specific search space may be configured using RRC.

[0199] The search space and / or each control resource set may assume a REG to CCE mapping (e.g., for use within it). The same REG to CCE mapping may be used. Localized and / or distributed DCCH candidates may be located in different search spaces. When the same REG to CCE mapping is assumed within each control resource set, localized and / or distributed PDCCH candidates may be located in different control resource sets. Multiple (e.g., two) overlapping control resource sets may be either distributed or localized (as an example, whether they contain a common search space or a WTRU-specific search space).

[0200] The resulting DCI structure may be a hierarchical or multi-level structure (e.g., allowing for streamlined design and minimization of control channel overhead by sending the minimum amount of information that enables the WTRU to obtain the WTRU control information). In an example of a multi-layer structure, a 3-layer structure (with additional sublayers) may be used. Level 1 may include system information. The system information may be obtained from a broadcast channel and may be obtained from a two-phase broadcast channel. In a two-phase broadcast channel, the first phase may send minimum system information and the second phase may send additional information as needed. Level 2 may include one or more group-common DCIs. Level 2 may be optional. For example, WTRU group-common information may be transmitted in a single-slot transmission. As an example, by using group-common DCI, resources that can be detected by the WTRU during control channel decoding may be specified (e.g., implicitly) and / or the number of blind decodes required may be reduced. Level 3 may include user-specific DCI. User-specific DCI may include information specific to the transmitting / receiving WTRU and may include one or more of the following: PMI, channel quality indicator (CQI), requested transmit power, transmission scheme, or resources, etc. This type of information can be multi-stage. For example, long-term information can be separated from rapidly changing information to further reduce overhead. Level 3 can contain one or more sub-levels. For example, level 3.1 can include user-specific DCI stage 1. Level 3.2 can include user-specific DCI stage 2.

[0201] The DCI layer may be determined by the gNB and / or may be requested by the WTRU on demand. In a group-common DCI, a request from a WTRU that is a member of a group may trigger the sending of all or part of the group information. The request may be a modified service request for general or specific information.

[0202] The processes and approaches described herein may be applied in any combination, may be applied to other wireless technologies, and may be applied to other services.

[0203] The above processing may be implemented in a computer program, software and / or firmware that introduces a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electrical signals (transmitted via a wired or wireless connection) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, buffer memory, semiconductor storage devices, magnetic media such as internal hard disk boxes and removable disks, magneto-optical media, and / or optical media such as CD-ROM disks and / or digital versatile disks (DVDs). A processor associated with the software may be used to implement a radio frequency transceiver used in a WTRU, a terminal, a base station, an RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: processor; as well as a memory configured to communicate with the processor and to store instructions that, when executed by the processor, cause the WTRU to: Receive control resource set (CORESET) configuration information; determining, based on the CORESET configuration information, a control channel element (CCE) to resource element group (REG) mapping for a CORESET, wherein the CCE to REG mapping indicates a REG bundle associated with the CCE, wherein the REG bundle includes a plurality of REGs, wherein mapping of the plurality of REGs to the REG bundle is determined based on a number of REGs included in the REG bundle and a number of REGs in the CORESET, and wherein the CCE to REG mapping is determined based on an index associated with the CCE and the number of REGs included in the REG bundle; and A physical downlink control channel (PDCCH) transmission associated with the CORESET is decoded based on the determined CCE-to-REG mapping.

2. The WTRU of claim 1 , wherein the plurality of REGs in the CORESET are numbered in ascending order in a time-first manner.

3. The WTRU of claim 1 , wherein the plurality of REGs in the CORESET are numbered in increasing order in frequency.

4. The WTRU of claim 1 , wherein: The processor is further configured to determine whether the CCE to REG mapping is interleaved or non-interleaved based on the CORESET configuration information.

5. The WTRU of claim 4, wherein: In case the CORESET configuration information indicates that the CCE-to-REG mapping is interleaved, the CCE-to-REG mapping is determined based on a modulo operation using a modulo base, wherein the modulo base is the number of REG bundles in the CORESET.

6. The WTRU of claim 5, wherein: The modular operation has a multiplication factor that is a function of the number of REG bundles in the CORESET.

7. The WTRU of claim 4, wherein the processor is further configured by radio resource control signaling to determine whether the CCE to REG mapping is interleaved or non-interleaved.

8. The WTRU of claim 1 , wherein: The CORESET includes a plurality of REGs, and when the CORESET covers one Orthogonal Frequency Division Multiplexing (OFDM) symbol, the plurality of REGs are numbered in increasing order in frequency.

9. The WTRU of claim 1 , wherein the CORESET comprises a plurality of REGs in the CORESET, the plurality of REGs being numbered based on a number of orthogonal frequency division multiplexing (OFDM) symbols in the CORESET.

10. A method performed by a wireless transmit / receive unit (WTRU), comprising: Receive control resource set CORESET configuration information; Based on the CORESET configuration information, determining a control channel element (CCE) to resource element group (REG) mapping for a CORESET, wherein the CCE to REG mapping indicates a REG bundling associated with the CCE, wherein: The REG bundle includes a plurality of REGs, wherein mapping of the plurality of REGs to the REG bundle is determined based on the number of REGs included in the REG bundle and the number of REGs in the CORESET, and wherein the CCE to REG mapping is determined based on an index associated with the CCE and the number of REGs included in the REG bundle; and A physical downlink control channel (PDCCH) transmission associated with the CORESET is decoded based on the determined CCE-to-REG mapping.

11. The method of claim 10, wherein the plurality of REGs in the CORESET are numbered in increasing order in a time-first manner.

12. The method of claim 10, wherein the plurality of REGs in the CORESET are numbered in increasing order in frequency.

13. The method according to claim 10, further comprising: Based on the CORESET configuration information, it is determined whether the CCE to REG mapping is interleaved or non-interleaved.

14. The method according to claim 13, wherein: In case the CORESET configuration information indicates that the CCE-to-REG mapping is interleaved, the CCE-to-REG mapping is determined based on a modulo operation using a modulo base, wherein the modulo base is the number of REG bundles in the CORESET.

15. The method according to claim 14, wherein: The modular operation has a multiplication factor that is a function of the number of REG bundles in the CORESET.

16. The method according to claim 13, further comprising: The radio resource control signaling is configured to determine whether the CCE to REG mapping is interleaved or non-interleaved.

17. The method according to claim 10, wherein: The CORESET includes a plurality of REGs, and when the CORESET covers one Orthogonal Frequency Division Multiplexing (OFDM) symbol, the plurality of REGs are numbered in increasing order in frequency.

18. The method according to claim 10, wherein: The CORESET includes a plurality of REGs in the CORESET, the plurality of REGs being numbered based on the number of orthogonal frequency division multiplexing (OFDM) symbols in the CORESET.

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