WO2025072679A1

WO2025072679A1 - Pdsch layer aggregation for radar coexistence

Info

Publication number: WO2025072679A1
Application number: PCT/US2024/048862
Authority: WO
Inventors: Joe Huang; Sudhir Pattar; Daniel Steinbach; Phillip LEITHEAD
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2023-09-27
Filing date: 2024-09-27
Publication date: 2025-04-03
Anticipated expiration: 2026-03-27

Abstract

Methods and triggering mechanisms for transmitting multiple redundancy versions of PDSCH transmissions simultaneously over MIMO layers (referred to as PDSCH layer aggregation/sub-aggregation) are described to improve HARQ efficiency in a rich scattering environment (and/or dual polarization). A base station receives/determines information characterizing operation of a radar, such as AOA, frequency, BW, power, etc. The base station determines the rank of a PDSCH transmission based on CSI-RS report(s) provided by a WTRU and if the rank > 1, the base station may determine and dynamically activate PDSCH layer aggregation/sub-aggregation to provide enhanced reliability and reduced latency to mitigate high-power interferers. The base station indicates the use of PDSCH layer aggregation/sub-aggregation to the WTRU in the DCI signaling and transmits multiple redundancy versions of a PDSCH codeword across multiple MIMO layers and multiple TRPs if applicable. Additional embodiments are disclosed.

Description

PDSCH LAYER AGGREGATION FOR RADAR COEXISTENCE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/585,777, filed September 27, 2023, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] Recent trends are driving researchers to create solutions for cellular network deployments in the presence of high-power interferers (e.g., radio detection and ranging (RADAR) systems, referred to hereinafter as radar(s)). Although the baseline functionality provided by 5G could be used to provide some level of coexistence with interferers such as radars, enhancements will be required to realize the full 5G potential.

[0003] When a high power interferer such as a radar operates in a band that overlaps with the resource blocks (RBs) allocated to a user equipment (UE) for a physical downlink shared channel (PDSCH), the UE would not be able to reliably receive data radio bearer (DRB) and signaling radio bearer (SRB) traffic, as well as hybrid automatic repeat request (HARQ) retransmissions, particularly when downlink multiple input multiple output (MIMO) and/or multi-transmit receive point (TRP) transmission is applied. Therefore, there is a need for improvements to ensure robust PDSCH MIMO and multi-TRP transmission and reception can occur when coexisting with high-power interferers such as radars.

SUMMARY

[0004] Various aspects are disclosed to ensure robust PDSCH MIMO and multi-TRP transmission and reception when coexisting with high-power interferers such as radars. According to one aspect, methods and dynamic triggering mechanisms of single TRP PDSCH layer aggregation are disclosed with or without repetition for UEs, also referred to herein as a wireless transmit receive unit (WTRU), that will incur interference from radars.

[0005] In one aspect of the embodiments, a base station/method implemented by a base station, e.g., a gNB, may include determining or receiving information characterizing an operation of a high-power interferer such as a radar. Based on the information, e.g., compared with one or more interference thresholds, the base station may determine a WTRU may incur interference in receiving one or more physical downlink shared channel (PDSCH) codewords. The base station may determine to use PDSCH layer aggregation/sub- aggregation and send downlink control information (DCI) to the WTRU indicating PDSCH layer aggregation/sub-aggregation will be used. Next, the base station may send to the WTRU, multiple redundancy versions of the one or more PDSCH codewords across two or more layers of a multiple-input multiple-output (MIMO) transmission. In one example, for each redundancy version of the multiple redundancy versions, each code block of the one or more PDSCH codewords is distributed evenly across the two or more layers of the MIMO transmission. In another example, code blocks for different redundancy versions of the one or more PDSCH codewords are mapped to different layers of the MIMO transmission. In one aspect, the multiple redundancy versions of the PDSCH codeword(s) of the MIMO transmission is sent across multiple transmit receive points (TRPs) to the WTRU.

[0006] In another aspect, prior to sending the DCI, the base station may determine to use PDSCH layer aggregation/sub-aggregation based on a channel state information reference signal (CSI-RS) report from the WTRU indicating a PDSCH MIMO rank is greater than 1, i.e., at least two layers, which may further relate to at least one transmit receive point (TRP) having a rank greater than 1, in the case of multi-TRP transmission. As additional potential options, the DCI may further indicates one or more of a time domain repetition and/or a frequency domain repetition of the one or more PDSCH codewords.

[0007] According to another aspect, methods and dynamic triggering mechanisms of multi-TRP PDSCH layer aggregation/sub-aggregation are disclosed, with or without repetition, for cell edge WTRUs that will incur interference from high-power interferes such as radars.

[0008] In another aspect of the embodiments, a WTRU/a method implemented in a WTRU may include receiving, from a network, DCI indicating use of layer aggregation/sub-aggregation in a multiple-input multipleoutput (MIMO) transmission of one or more physical downlink shared channel (PDSCH) codewords. The WTRU next receives the PDSCH MIMO transmission and extracts multiple redundancy versions of each code block of the codeword(s) from each layer of the received MIMO transmission The WTRU performs hybrid automatic repeat request (HARO) combining from the extracted multiple redundancy versions of each block code, and based on the HARO combining, the WTRU reports an acknowledgement (ACK) or negative ACK (NACK) for transport blocks or code block groups (CBGs) to the network. In one example, the layer (sub)aggregated PDSCH MIMO transmission is received from a base station. In another example, the MIMO transmission is received from multiple TRPs. Additional aspects, features and/or advantages will become apparent from the example embodiments that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

[0010] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0011] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0012] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment; [0013] FIG. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0014] FIG. 2A shows example information elements used for physical downlink shared channel (PDSCH) configuration;

[0015] FIG. 2B shows additional example information elements used for the PDSCH configuration;

[0016] FIG. 2C shows additional example information elements used for the PDSCH configuration;

[0017] FIG. 3A illustrates an of serial mapping for PDSCH layer aggregation for a rank 2 multiple-input multiple-output (MIMO) transmission according to one embodiment;

[0018] FIG. 3B illustrates an example of serial mapping for PDSCH layer aggregation for a rank 3 MIMO transmission;

[0019] FIG. 3C illustrates an example of serial mapping for PDSCH layer aggregation for a rank 4 MIMO transmission;

[0020] FIG. 3D illustrates an example of serial mapping for PDSCH layer aggregation for a rank 5 MIMO transmission;

[0021] FIG. 3E illustrates an example of serial mapping for PDSCH layer aggregation for a rank 6 MIMO transmission;

[0022] FIG. 3F illustrates an example of serial mapping for PDSCH layer aggregation for a rank 7 MIMO transmission;

[0023] FIG. 3G illustrates an example of serial mapping for PDSCH layer aggregation for a rank 8 MIMO transmission;

[0024] FIG. 4A illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 2 MIMO transmission according to another embodiment;

[0025] FIG. 4B illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 3 MIMO transmission;

[0026] FIG. 4C illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 4 MIMO transmission;

[0027] FIG. 4D illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 5 MIMO transmission;

[0028] FIG. 4E illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 6 MIMO transmission;

[0029] FIG. 4F illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 7 MIMO transmission;

[0030] FIG. 4G illustrates an example of parallel layer mapping for PDSCH layer aggregation for a rank 8 MIMO transmission; [0031] FIG. 5 is a flow diagram illustrating an example method for a radio access network (RAN) node, e.g., a base station/gNB, utilizing dynamic triggering of PDSCH layer aggregation according to one embodiment;

[0032] FIG. 6 is a flow diagram illustrating an example method for a wireless transmit receive unit (WTRU) utilizing dynamic triggering of PDSCH layer aggregation according to one embodiment; and

[0033] FIG. 7 is a flow diagram detailing an example method for a RAN node, e.g., a base station/gNB, utilizing dynamic triggering of PDSCH layer aggregation according to another embodiment.

DETAILED DESCRIPTION

[0034] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), singlecarrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-S- OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0035] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though itwill be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station (STA), 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 telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0036] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0037] The base station 114a may be part of the RAN 104, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, 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, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0038] 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).

[0039] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High-Speed Uplink (UL) Packet Access (HSUPA).

[0040] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0041] In an 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 NR. [0042] In an 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 implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by 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 , an eNB and a gNB).

[0043] 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 (i.e, Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0044] The base station 114b in FIG 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0045] The RAN 104 may be in communication with the CN 106, 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 of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc, and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0046] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), 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 communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0047] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1 A may be configured to communicate with the base station 114a, which may employ a cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0048] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0049] 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 in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0050] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals. [0051] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0052] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0053] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0054] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the 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 (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li- ion), etc.), solar cells, fuel cells, and the like.

[0055] 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) regarding 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 over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment

[0056] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor and the like.

[0057] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e g., associated with particular subframes for both the UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e g., for transmission) or the DL (e g., for reception)).

[0058] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the ON 106.

[0059] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0060] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0061] The ON 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are depicted as part of the ON 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0062] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c 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, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may 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

[0063] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0064] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0065] The ON 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 may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves 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 the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. [0066] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0067] In representative embodiments, the other network 112 may be a WLAN.

[0068] A WLAN in Infrastructure 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 have access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer-to- peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad-hoc” mode of communication.

[0069] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0070] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0071] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0072] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g , only support for) certain and/or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0073] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0074] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0075] FIG. 1 D is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0076] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating 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, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0077] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and/or lasting varying lengths of absolute time). [0078] 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 the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0079] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0080] The CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0081] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For 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, services for MTC access, and the like The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi. [0082] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0083] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, 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. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.

[0084] The CN 106 may facilitate communications with other networks For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves 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 the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0085] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0086] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network The emulation device may be directly coupled to another device for purposes of testing and/or performing testing using over-the-air wireless communications. [0087] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0088] In new radio (NR), the downlink MIMO scheme is non-codebook based. Every downlink channel transmission that is to be decoded by the WTRU includes demodulation reference signals (DM-RS) for channel estimation, which are precoded the same way as the PDSCH. The manner in which it is precoded is not specified and the precoding itself is transparent to the WTRU. The WTRU is only informed about the transmission rank and the DM-RS port-to-layer mapping. Only one transmission scheme (i e., transmission scheme 1) is defined for the PDSCH and is used for all PDSCH transmissions. For transmission scheme 1, the WTRU may assume that a gNB transmission on the PDSCH would be performed with up to 8-transmission layers on antenna ports 1000-1011, subject to defined DM-RS reception procedures.

[0089] The MIMO layers, sometimes referred to as streams or data streams, in the case of spatial multiplexing with up to four layers, are mapped to a single codeword, which means that channel bits from a code block are distributed evenly across the layers. The modulation order and code rate on all layers is the same for rank up to 4. The signal-to-noise ratio (SNR) on each layer can be different, but the single-codeword arrangement ensures that the code blocks distributed across the layers will experience the same average SNR and, therefore, using the same code rate is appropriate. In the case of significant per layer SNR variation, layer dependent modulation order selection can provide benefits, but thus far, this scheme has not been adopted by the Third Generation Partnership Program (3GPP). On the other hand, the benefits of the single-codeword mapping include less channel state information (CSI) variation and feedback overhead reduction for both hybrid automatic repeat request (HARO) and CSI.

[0090] When the MIMO rank is greater than four, then the MIMO layers are mapped to two codewords, and codewords are encoded and decoded independently and they go through an independent modulation and coding scheme (MCS) selection and HARQ retransmission process. Two codewords were selected because simulations showed that this solution gave adequate performance Because of the independent MCS selection for the case of rank greater than four, the modulation order can be different in different layers. The mapping of layers to codewords is fixed. In the case of even rank, the layers are distributed equally. In the case of odd rank, one more layer is mapped to the second codeword than to the first codeword.

[0091] In addition, NR adopts the concept of physical resource block (PRB) bundling in the downlink. PRB bundling means that the WTRU can assume that the gNB uses the same MIMO precoder across a number of contiguous RBs. This increases the available channel estimation processing gain, which in turn improves the channel estimation quality. The bundling size is p_{pwp t} RBs, where p_{pwp t} can be 2, 4, or ‘wideband’. The wideband bundling option means that the WTRU can assume that the gNB uses the same precoding across all allocated PDSCH RBs Wideband bundling only applies to contiguous resource allocation in the frequency domain.

[0092] Multi-TRP Transmission. In order to improve the performance of the cell edge users and provide a more balanced quality of service in the coverage area, a multi-transmit receive point (TRP) cooperative transmission scheme is introduced in NR Multi-TRP cooperative transmission can improve the performance of the cell edge users through noncoherent joint transmission (NC-JT) or diversity transmission among multiple TRPs, thereby better supporting the enhanced mobile broadband (eMBB) services and ultra-reliable low latency communications (URLLC) services. In particular, the multi-TRP-based diversity transmission scheme is mainly used to improve the transmission reliability of URLLC services, in which multiple TRPs repeatedly transmit the same data in order to improve the transmission reliability, thereby better supporting the URLLC service. In an example, for NR R16, the cooperative transmission is limited to two TRPs.

[0093] PDSCH Time Domain Resource Allocation (TDRA) When the WTRU is scheduled to receive the PDSCH by a downlink control information (DCI), the Time domain resource assignment field value m of the DCI provides a row index m + 1 to an allocation table. The determination of the used resource allocation table is pre-defined and the indexed row defines the slot offset Ko, the start and length indicator (SLIV), or directly the start symbol S and the allocation length L, and the PDSCH mapping type to be assumed in the PDSCH reception.

[0094] Given the parameter values of the indexed row:

[0095] The reference point SO for starting symbol S is defined as:

[0096] (i) if configured with referenceOfSLIVDCI-1-2, and when receiving PDSCH scheduled by

DCI format 1_2 with cyclic redundancy check (CRC) scrambled by radio network temporary identifiers C-RNTI, MCS-C-RNTI, CS-RNTI with Ko=O, and PDSCH mapping Type B, the starting symbol S is relative to the starting symbol So of the PDCCH monitoring occasion where the DCI format 1_2 is detected;

[0097] (ii) otherwise, the starting symbol S is relative to the start of the slot using So=O.

[0098] The number of consecutive symbols L counting from the starting symbol S allocated for the PDSCH are determined from the start and length indicator SLIV using the following equations: if ^(L ’¹⁾ - ⁷ then

SLIT = 14 - (L - l) +5 . q -J else

SLIV = 14 -(14 - A + 1) + (14 - 1 -S) Eq 2 where 0 < <14-S [0099] The PDSCH mapping type may be set to Type A or Type B.

[0100] The WTRU shall consider the S and L combinations defined in TABLE 1 below, satisfying 5₀ + s + L < 14 for normal cyclic prefix and _o + 5 + L < 12 for extended cyclic prefix as valid PDSCH allocations:

Note 1 : S = 3 is applicable only if dmrs-TypeA-Position - 3

TABLE 1 : Valid S and L combinations

[0101] PDSCH Aggregation. Referring to FIGs. 2A-2C, PDSCH configuration information elements (lEs) and related parameters are shown in respective configurations 200, 230 and 260. If a WTRU is configured with higher layer parameter repetitionNumber or if the WTRU is configured by repetitionScheme set to one of ' fdmSchemeA', ' fdmSchemeB' and 'tdmSchemeA', the WTRU does not expect to be configured with pdsch- AggregationFactor. A WTRU does not expect to be configured with repetitionScheme, if the WTRU is configured with higher layer parameter repetitionNumber. The parameter repetitionNumber indicates the number of PDSCH transmission occasions for the slot-based repetition scheme in the IE RepetitionSchemeConfig.

[0102] The parameter fdm-TDM configures the WTRU with a repetition scheme among fdmSchemeA, fdmSchemeB and tdmSchemeA as specified in clause 5.1 of 3GPP Technical Specification TS 38 214. The network does not set this field to release. Upon reception of this field 260 in FIG. 2C RepetitionSchemeConfig- r16, the WTRU shall release slotBased if previously configured in the same instance of RepetitionSchemeConfig-r16.

[0103] The parameter sequenceOffsetForRV is for slot-based repetition scheme, selected redundancy version (RV) sequence is applied to transmission occasions associated to the first transmission control indicator (TCI) state. The RV sequence associated to the second TCI state is determined by a RV offset from that selected RV sequence.

[0104] The parameter slotBased configures the WTRU with slot-based repetition scheme. The Network always configures this field when the parameter repetitionNumber is present in the IE PDSCH- TimeDomainResourceAllocation List. The network does not set this field to release. Upon reception of this field in RepetitionSchemeConfig-r16, the WTRU shall release fdm-TDM if previously configured in the same instance of RepetitionSchemeConfig-r16.

[0105] The parameter startingSymbolOffsetK identifies the starting symbol of the second transmission occasion has a K symbol offset relative to the last symbol of the first transmission occasion. When the WTRU is configured with tdmSchemeA, the parameter startingSymbolOffsetK is present, otherwise it is absent. [0106] The parameter tciMapping enables the TCI state mapping method to PDSCH transmission occasions.

[0107] PDSCH Aggregation configured via pdschAggregationFactor. When receiving a PDSCH scheduled by DCI format 1_1 or 1_2 in PDCCH with CRC scrambled by C-RNTI, MCS-C-RNTI, orCS-RNTI with new data indicator (NDI)=1 , if the WTRU is configured with pdsch-AggregationFactor in the pdsch-config, the same symbol allocation is applied across the pdsch-AggregationFactor consecutive slots. When receiving a PDSCH scheduled by DCI format 1_1 or 1_2 in PDCCH with CRC scrambled by CS-RNTI with NDI=0, or PDSCH scheduled without corresponding physical downlink control channel (PDCCH) transmission using sps-Config and activated by DCI format 1_1 or 1_2, the same symbol allocation is applied across the pdsch- AggregationFactor, in sps-Config if configured or in pdsch-config otherwise, consecutive slots. The WTRU may expect that the transport block (TB) is repeated within each symbol allocation among each of the pdsch- AggregationFactor consecutive slots and the PDSCH is limited to a single transmission layer. The redundancy version (rv) to be applied on the n^th transmission occasion of the TB, where n = 0, 1 , ...pdsch- AggregationFactor-t , is determined according to TABLE 2 below and "rvid indicated by the DCI scheduling the PDSCH" in TABLE 2 is assumed to be 0 for PDSCH scheduled without corresponding PDCCH transmission using sps-Config and activated by DCI format 1_1 or 1_2.

TABLE 2: Applied redundancy version when pdsch-AggregationFactor is present

[0108] PDSCH Aggregation Configured via repetitionNumber. When a WTRU is configured by the higher layer parameter repetitionNumber in PDSCH-TimeDomainResourceAllocation, the WTRU may expect to be indicated with one or two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' together with the DCI field 'Time domain resource assignment' indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResource Allocation and DM-RS port(s) within one code division multiplexing (CDM) group in the DCI field 'Antenna Port(s)¹.

[0109] When two TCI states are indicated in a DCI with 'Transmission Configuration Indication' field, the WTRU may expect to receive multiple slot level PDSCH transmission occasions of the same TB with two TCI states used across multiple PDSCH transmission occasions in the repetitionNumber consecutive slots. [0110] When one TCI state is indicated in a DCI with 'Transmission Configuration Indication' field, the WTRU may expect to receive multiple slot level PDSCH transmission occasions of the same TB with one TCI state used across multiple PDSCH transmission occasions in the repetitionNumber consecutive slots.

[0111] When a WTRU is not indicated with a DCI that DCI field 'Time domain resource assignment indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and it is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration indication' and DM- RS port(s) within two CDM groups in the DCI field 'Antenna Port(s)', the WTRU may expect to receive a single PDSCH where the association between the DM-RS ports and the TCI states are pre-defined.

[0112] When a WTRU is not indicated with a DCI that DCI field 'Time domain resource assignment indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and it is indicated with one TCI states in a codepoint of the DCI field 'Transmission Configuration Indication', the WTRU procedure for receiving the PDSCH upon detection of a PDCCH follows Clause 5.1 of TS 38.214.

[0113] When a WTRU configured by the higher layer parameter PDSCH-config that indicates at least one entry contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, the following options (1)- (3) are possible:

[0114] (1) If two TCI states are indicated by the DCI field 'Transmission Configuration Indication' together with the DCI field 'Time domain resource assignment indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAllocation and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', the same SLIV is applied for all PDSCH transmission occasions across the repetitionNumber consecutive slots, the first TCI state is applied to the first PDSCH transmission occasion and resource allocation in time domain for the first PDSCH transmission occasion follows Clause 5.1.2.1 of TS 38.214.

[0115] When the value indicated by repetitionNumber in PDSCH-TimeDomainResourceAllocation equals two, the second TCI state is applied to the second PDSCH transmission occasion. When the value indicated by repetitionNumber in PDSCH-TimeDomainResourceAllocation is larger than two, the WTRU may be further configured to enable cyclicMapping or sequenticalMapping in tciMapping.

[0116] When cyclicMapping is enabled, the first and second TCI states are applied to the first and second PDSCH transmission occasions, respectively, and the same TCI mapping pattern continues to the remaining PDSCH transmission occasions.

[0117] When sequenticalMapping is enabled, the first TCI state is applied to the first and second PDSCH transmission occasions, and the second TCI state is applied to the third and fourth PDSCH transmission occasions, and the same TCI mapping pattern continues to the remaining PDSCH transmission occasions.

[0118] The WTRU may expect that each PDSCH transmission occasion is limited to two transmission layers. For all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied is derived according to TABLE 2 above, where n is counted only considering PDSCH transmission occasions associated with the first TCI state. The redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 3 below, where additional shifting operation for each redundancy version rv_s is configured by higher layer parameter sequenceOffsetforRV and n is counted only considering PDSCH transmission occasions associated with the second TCI state

TABLE 3: Applied redundancy version for the second TCI state when sequenceOffsetforRV is present

[0119] (2) If one TCI state is indicated by the DCI field 'Transmission Configuration Indication' together with the DCI field 'Time domain resource assignment' indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAliocation and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', the same SLIV is applied for all PDSCH transmission occasions across the repetitionNumber consecutive slots, the first PDSCH transmission occasion follows Clause 5.1.2 1 of TS 38.214, the same TCI state is applied to all PDSCH transmission occasions. The WTRU may expect that each PDSCH transmission occasion is limited to two transmission layers. For all PDSCH transmission occasions, the redundancy version to be applied is derived according to TABLE 2, where n is counted considering PDSCH transmission occasions.

[0120] (3) Otherwise, the WTRU is expected to receive a single PDSCH transmission occasion, and the resource allocation in the time domain follows Clause 5.1.2.1 of TS 38.214.

[0121] PDSCH Aggregation configured via repetition Scheme. When a WTRU is configured by higher layer parameter repetitionScheme set to one of 'fdmSchemeA', 'fdmSchemeB', 'tdmSchemeA', if the WTRU is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' and DM- RS port(s) within one CDM group in the DCI field 'Antenna Portfs)'.'

[0122] -When two TCI states are indicated in a DCI and the WTRU is set to 'fdmSchemeA', the WTRU shall receive a single PDSCH transmission occasion of the TB with each TCI state associated to a non-overlapping frequency domain resource allocation.

[0123] -When two TCI states are indicated in a DCI and the WTRU is set to 'fdmSchemeB', the WTRU shall receive two PDSCH transmission occasions of the same TB with each TCI state associated to a PDSCH transmission occasion which has non-overlapping frequency domain resource allocation with respect to the other PDSCH transmission occasion.

[0124] -When two TCI states are indicated in a DCI and the WTRU is set to 'tdmSchemeA', the WTRU shall receive two PDSCH transmission occasions of the same TB with each TCI state associated to a PDSCH transmission occasion which has non-overlapping time domain resource allocation with respect to the other PDSCH transmission occasion and both PDSCH transmission occasions shall be received within a given slot. [0125] For a WTRU configured by the higher layer parameter repetitionScheme set to 'fdmSchemeA' or 'fdmSchemeB' and when the WTRU is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration indication' and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)'

[0126] -If Pg_{WP t} is determined as "wideband", the first

PRBs are assigned to the firstTCI state and the remaining

PRBs are assigned to the second TCI state, where n_PRB is the total number of allocated PRBs for the WTRU.

[0127] -If P^p i is determined as one of the values among {2, 4}, even PRGs within the allocated frequency domain resources are assigned to the first TCI state and odd PRGs within the allocated frequency domain resources are assigned to the second TCI state, wherein the PRGs are numbered continuously in increasing order with the first PRG index equal to 0

[0128] -The WTRU is not expected to receive more than two PDSCH transmission layers for each PDSCH transmission occasion.

[0129] For a WTRU configured by the higher layer parameter repetitionScheme set to 'fdmSchemeB', and when the WTRU is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' and DM-RS port(s) within one CDM group in the DCI field ‘Antenna Port(s)', each PDSCH transmission occasion shall follow the Clause 7.3.1 of TS 38.211 with the mapping to resource elements determined by the assigned PRBs for corresponding TCI state of the PDSCH transmission occasion, and the WTRU shall only expect at most two code blocks per PDSCH transmission occasion when a single transmission layer is scheduled and a single code block per PDSCH transmission occasion when two transmission layers are scheduled. For two PDSCH transmission occasions, the redundancy version to be applied is derived according to TABLE 2, where n = 0, 1 are applied to the first and second TCI state, respectively.

[0130] To determine the modulation order, target code rate, and transport block size(s) in the physical downlink shared channel, the WTRU shall first:

[0131] -read the 5-bit modulation and coding scheme field (/_MCs) in the DCI to determine the modulation order (Q_ra) and target code rate (R) based on the procedure defined in Clause 5.1.3.1 of TS 38.214, and [0132] -read 'redundancy vers/on'field (rv) in the DCI to determine the redundancy version. [0133] And secondly:

[0134] -the WTRU shall use the number of layers (u), the total number of allocated PRBs before rate matching (JIPRB) to determine to the transport block size based on the procedure defined in Clause 5.1.3.2 of TS 38.214.

[0135] For a WTRU configured with the higher layer parameter repetitionScheme set to 'fdmSchemeB', and when the WTRU is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', the determined modulation order of PDSCH transmission occasion associated with the first TCI state is applied to the PDSCH transmission occasion associated with the second TCI state.

[0136] When a WTRU is configured by the higher layer parameter repetitionScheme set to 'tdmSchemeA' and indicated DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)’, the number of PDSCH transmission occasions is derived by the number of TCI states indicated by the DCI field 'Transmission Configuration Indication' of the scheduling DCI:

[0137] -If two TCI states are indicated by the DCI field 'Transmission Configuration Indication', the WTRU is expected to receive two PDSCH transmission occasions, where the first TCI state is applied to the first PDSCH transmission occasion and resource allocation in time domain for the first PDSCH transmission occasion follows Clause 5 1.2.1 of TS 38 214. The second TCI state is applied to the second PDSCH transmission occasion, and the second PDSCH transmission occasion shall have the same number of symbols as the first PDSCH transmission occasion. If the WTRU is configured by the higher layers with a value K in StartingSymbolOffsetK, it shall determine that the first symbol of the second PDSCH transmission occasion starts after K symbols from the last symbol of the first PDSCH transmission occasion. If the value K is not configured via the higher layer parameter StartingSymbolOffsetK, K = 0 shall be assumed by the WTRU. The WTRU is not expected to receive more than two PDSCH transmission layers for each PDSCH transmission occasion. For two PDSCH transmission occasions, the redundancy version to be applied is derived according to TABLE 2, where n = 0, 1 applied respectively to the first and second TCI state. The WTRU expects the PDSCH mapping type indicated by DCI field 'Time domain resource assignment' to be mapping type B, and the indicated PDSCH mapping type is applied to both PDSCH transmission occasions

[0138] -Otherwise, the WTRU is expected to receive a single PDSCH transmission occasion, and the resource allocation in the time domain follows Clause 5.1.2.1 of TS 38.214.

[0139] As mentioned previously, recent trends are driving researchers to create solutions for cellular network deployments in the presence of high-power narrowband interferes (e.g., radars). Although the baseline functionality provided by 5G could be used to provide some level of coexistence with radars, enhancements will be required to realize the full 5G potential.

[0140] When a high-power interferer such as radar operates in a band that overlaps with the RBs allocated to the WTRU for receiving PDSCH transmissions, the WTRU may not be able to reliably receive data radio bearer (DRB) and/or signaling radio bearer (SRB) traffic, as well as HARQ retransmissions, particularly when downlink MIMO and/or multi-TRP transmission is applied. Therefore, there is a need for improved mechanisms to ensure robust PDSCH MIMO and multi-TRP transmission and reception can occur when coexisting with high-power interferers such as radars.

[0141] According to example embodiments disclosed herein, improved robustness of PDSCH MIMO and sin gle/multi-T RP transmission and reception may be provided when coexisting with high-power interferers such as radars. According to a first example solution of the embodiments, dynamic triggering for single TRP PDSCH layer aggregation, with or without repetition, may be used for WTRUs that will incur interference from radars or the like. According to a second example solution of the embodiments, dynamic triggering of multi-TRP PDSCH layer aggregation, with or without repetition, may be used for cell edge WTRUs that will incur interference from radars and the like.

[0142] Single TRP PDSCH Layer Aggregation. PDSCH aggregation of multiple redundancy versions in the time domain for a single TRP transmission is currently supported in 3GPP. In the following solutions, methods and triggering mechanisms of multiple redundancy versions transmitting simultaneously over multiple MIMO layers (referred to as PDSCH layer aggregation/sub-aggregation) are described to further improve HARQ efficiency in a rich scattering environment (and/or dual polarization) with rank greater than 1 .

[0143] To coexist with a high-power interferer such as radar, a gNB may configure PDSCH layer aggregation for WTRUs that may likely incur interference from the radar or other high-power interferers. It should be recognized that while the term “radar” is used in the examples that follows, the embodiments are not limited to radar interference and may equally be applied for other interferers or conditions for which PDSCH layer aggregation/sub-aggregation may be beneficial.

[0144] In various embodiments, the configuration of PDSCH layer aggregation may be triggered for a WTRU when the radar interference exceeds a threshold. The threshold may be preconfigured, determined dynamically or provided by an external entity. Different thresholds may be defined and selected by the gNB. For example, a set of thresholds may be defined based on the MCS or modulation order. The gNB then selects the appropriate threshold based on the MCS or modulation order used for the PDSCH. In other examples, the threshold may be selected based on characteristics of the data, characteristics of the service and/or characteristics of the device, e.g., the QoS of the data being transmitted on the PDSCH, the service being provided to the device, and/or the device type.

[0145] The gNB may use information characterizing the operation of the radar to determine the interference level pertinent to one or more WTRUs. In one example, radar angle of arrival (AOA) information is used by the gNB to determine the spatial direction of the radar interference in the cell. The gNB then configures PDSCH layer aggregation for WTRUs located in areas of the cell that may incur radar interference exceeding the threshold. The gNB may determine a WTRU’s location based on the spatial direction of a synchronization signal block (SSB) or channel state information reference signal (CSI-RS) that is quasi-collocated (QCL-ed) with the antenna port(s) used for transmission of the PDSCH. Alternatively, the WTRU’s location may be determined by the gNB using positioning algorithms, may be (pre)configured in the gNB via an operations, administration and maintenance (OAM) interface, or may be reported to the gNB by the WTRU. In addition, the load in a cell, e.g., number of Connected Mode WTRUs, may also be used when determining whether or not PDSCH layer aggregation should be configured. In certain examples, a number of discontinuous

[0146] Referring to FIGs. 3A-3G, illustrations of example serial layer mappings 300, 320, 350, 360, 370, 380 and 390 for PDSCH layer aggregation are shown for respective ranks 2-8 (i.e., using respective layers 0- 7) In one embodiment of PDSCH layer aggregation, the channel bits from each code block (CB) of the multiple redundancy versions of a codeword are distributed evenly across the MIMO layers (e.g., up to 4 layers per codeword), as illustrated in FIGs 3A-3G mappings 300, 320, 350, 350, 360, 370, 380 and 390 (the CB groups (CBGs) in the figures indicate code block groups). In these embodiments, while the SNR on each layer can be different, the code blocks distributed across the respective layers may experience the same average SNR.

[0147] In a second example embodiment, referring to FIGs. 4A-4G, illustrations of example parallel layer mappings 400, 420, 430, 440, 450, 460 and 470 for PDSCH layer aggregation are shown for respective ranks 2-8 (i.e., using respective layers 0-7). The codewords associated with different redundancy versions are mapped to different MIMO layers as illustrated in FIGs 4A-4G example mappings 400, 420, 430, 440, 450, 460 and 470. In these embodiments, the codewords associated with different redundancy versions may experience different SN Rs.

[0148] Single TRP PDSCH layer aggregation without repetition. In the case of single TRP MIMO transmission without repetition, a WTRU is neither configured with pdsch-AggregationFactornor indicated with a DCI that DCI field 'Time domain resource assignment' indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and it is indicated with one TCI state in a codepoint of the DCI field 'Transmission Configuration Indication', the WTRU procedure for receiving the PDSCH without layer aggregation may follow Clause 5.1 of TS 38.214.

[0149] The network can trigger PDSCH layer aggregation via the scheduling grant. For example, a 'layer aggregation’ bit can be defined in DCI format 1_1 and format 1_2. If the number of PDSCH transmission layers is equal to one or if the layer aggregation bit is set to 0, redundancy versions are determined by TABLE 2 above, with n = 0 for all layers, as per the current 3GPP specifications. On the other hand, if the number of PDSCH transmission layers is larger than or equal to two and if the layer aggregation bit is set to 1, redundancy versions can be determined by TABLES 4-10 below, if the downlink MIMO rank is equal to 2, 3, 4, 5, 6, 7 or 8, respectively.

TABLE 4: Applied redundancy version for rank=2 PDSCH layer aggregation

TABLE 5: Applied redundancy version for rank=3 PDSCH layer aggregation

TABLE 6: Applied redundancy version for rank=4 PDSCH layer aggregation

TABLE 7: Applied redundancy version for rank=5 PDSCH layer aggregation

TABLE 8: Applied redundancy version for rank=6 PDSCH layer aggregation

TABLE 9: Applied redundancy version for rank=7 PDSCH layer aggregation

TABLE 10: Applied redundancy version for rank=8 PDSCH layer aggregation

[0150] In addition, in certain embodiments, a 'layer sub-aggregation bit¹ may be further defined per codeword to facilitate tradeoff between reliability and capacity. In one embodiment, the channel bits from each redundancy version of a codeword may be distributed evenly across a subset of the available MIMO layers. Note that the 'layer sub-aggregation bit’ is sent only when 'layer aggregation bit’ is set to 1. For example, assuming a rank-4 MIMO, without layer aggregation, the MIMO can transmit 4 data streams (i.e., 4 codewords, sequentially or in parallel) over 4 MIMO layers leading to 4 x single stream throughput; with full layer aggregation, the MIMO can transmit 1 data stream with 4 repetitions (e.g., 4 different redundancy versions of a codeword, sequentially or in parallel) over 4 MIMO layers, leading to much strongererror recovery capabilities with single stream throughput; with layer sub-aggregation, the MIMO may transmit 2 data streams with 2 repetitions per data stream (e.g., two codewords, each with 2 different redundancy versions, sequentially or in parallel) over 4 MIMO layers, leading to 2 x single stream throughput with improved error recovery capabilities. [0151] If the ‘layer sub-aggregation bit’ for codeword 0 is set=1 , redundancy versions can be defined by TABLES 11 and 12 below.

TABLE 11 : Applied redundancy version for rank=3, 6 or 7 PDSCH layer sub-aggregation

TABLE 12: Applied redundancy version for rank=4 or 8 PDSCH layer sub-aggregation

[0152] If the 'layer sub-aggregation bit’ for codeword 1 is set=1, redundancy versions can be defined by TABLES 13 and 14 below.

TABLE 13: Applied redundancy version for rank=5 or 6 PDSCH layer sub-aggregation

TABLE 14: Applied redundancy version for rank=7 or8 PDSCH layer sub-aggregation

[0153] Single TRP PDSCH Layer Aggregation with Repetition. In the case of single TRP MIMO transmission with inter-slot time domain repetition, a WTRU configured by the higher layer parameter PDSCH- config that indicates at least one entry contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and if one TCI state is indicated by the DCI field 'Transmission Configuration indication' together with the DCI field 'Time domain resource assignment' indicating an entry which contains repetitionNumber in PDSCH- TimeDomainResourceAllocation and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', the WTRU may expect to receive multiple slot level PDSCH transmission occasions of the same TB with one TCI state used across multiple PDSCH transmission occasions in the repetitionNumber consecutive slots and the same SLIV is applied for all PDSCH transmission occasions across the repetitionNumber consecutive slots. [0154] In this case, the WTRU may expect that each PDSCH transmission occasion is limited to two transmission layers, as per the current 3GPP specifications If the number of PDSCH transmission layers is equal to one or if the layer aggregation bit is set to 0, redundancy versions are determined by TABLE 2 above, where n is counted considering PDSCH transmission occasions. If the number of PDSCH transmission layers is equal to two and the layer aggregation bit is set to 1 , redundancy versions can be determined by TABLE 15 below.

TABLE 15: Applied redundancy version for rank=2 PDSCH layer aggregation with repetition

[0155] In addition, if the number of PDSCH transmission layers can be set to be larger than two (e.g., up to four) and the layer aggregation bit is set to 1, redundancy versions can be determined by TABLES 16 and 17 below, if the downlink MIMO rank is equal to 3 or 4, respectively.

TABLE 16: Applied redundancy version for rank=3 PDSCH layer aggregation with repetition

TABLE 17: Applied redundancy version for rank=4 PDSCH layer aggregation with repetition

[0156] It is also possible to define layer sub-aggregation with repetition if the number of PDSCH transmission layers is larger than two, as exemplified by TABLES 18 and 19 below, for the cases of rank = 3 and 4, respectively.

TABLE 18: Applied redundancy version for rank=3 PDSCH layer sub-aggregation with repetition

TABLE 19: Applied redundancy version for rank=4 PDSCH layer sub-aggregation with repetition

[0157] In addition to bundled transmission, PDSCH layer aggregation may also be applied in the regular HARQ process. For example, the network sends redundancy version 0 during initial transmission and retransmitted multiple redundancy versions of the erroneous CBGs using layer aggregation (assuming rank > 1 is available during retransmission) to enhance reliability and reduce latency. In principle, the network can also send multiple redundancy versions of the erroneous CBGs using both layer aggregation and repetition, if deemed beneficial

[0158] When the WTRU receives the DCI signaling indicating the use of layer aggregation/sub-aggregation in PDSCH, the WTRU extracts multiple redundancy versions of each code block from different MIMO layers and performs HARQ combining from the multiple redundancy versions of each code block. Based on the decoding results, the WTRU then reports Ack/Nack feedback of the received transport blocks or code block groups (CBGs) to the network, as configured.

[0159] In various embodiments, the WTRU should inform the network of its capability to support PDSCH layer aggregation, as exemplified by the following information message in TABLE 20 below.

TABLE 20: Capabilities Message

[0160] In a second solution of the disclosed embodiments, multi-TRP PDSCH layer aggregation may be utilized. 3GPP R16 extended NR with support for downlink multi-TRP transmission, that is, the possibility to transmit PDSCH simultaneously from two geographically separated transmission points (TRPs). The two transmission points may, for example, correspond to different physical cell sites. Note that from the WTRU point of view, the multi-point transmission will still originate from a single logical cell. To this end, examples of the second solution will be exemplified in the context of multi-TRP transmission.

[0161] To coexist with a high-power interferer such as radar, a gNB may configure PDSCH layer aggregation for multi-TRP transmission to (physical) cell edge WTRUs that may incur interference from the radar. The configuration of PDSCH layer aggregation for multi-TRP transmission may be triggered for a cell edge WTRU when the radar interference exceeds a threshold. As in earlier embodiments, the threshold may be preconfigured, determined dynamically or provided by an external entity. Different thresholds may be defined and selected by the gNB. For example, a set of thresholds may be defined based on the MCS or modulation order. The gNB then selects the appropriate threshold based on the MCS or modulation order used for the PDSCH. In other examples, the threshold may be selected based on characteristics of the data, characteristics of the service and/or characteristics of the device (e.g., the QoS of the data being transmitted on the PDSCH, the service being provided to the device, and/or the device type).

[0162] The gNB may use information characterizing the operation of the radar to determine the interference level. In one example, radar AOA information is used by the gNB to determine the spatial direction of the radar interference in the cell. The gNB would then configure PDSCH layer aggregation for multi-TRP transmission to cell edge WTRUs located in areas of the cell that would incur radar interference exceeding a threshold. The gNB may determine a WTRU’s location based on the spatial direction of an SSB or CSI-RS that is QCL-ed with the antenna port(s) used for transmission of the PDSCH. Alternatively, the WTRU’s location may be determined by the gNB using positioning algorithms, may be (pre)configured in the gNB via an OAM interface, or may be reported to the gNB by the WTRU.

[0163] Multi-TRP PDSCH Layer Aggregation without Repetition.

[0164] In the case of multi-TRP non-coherent joint transmission (NC-JT) with a single DCI, a WTRU is not indicated with a DCI that DCI field 'Time domain resource assignment' indicating an entry which contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and it is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' and DM-RS port(s) within two CDM groups in the DCI field 'Antenna Port(s)', the WTRU may expect to receive a single PDSCH. In the single DCI based NC-JT, different layers of a PDSCH are transmitted in parallel from multiple transmission points on the same time frequency resources

[0165] The network can trigger PDSCH layer aggregation via the scheduling grant. For example, a 'layer aggregation’ bit can be defined in DCI format 1_1 and format 1_2. When the layer aggregation bit is set to 0, redundancy versions are determined by TABLE 2 above, with n = 0 for all layers. On the other hand, when the layer aggregation bit is set to 1 , redundancy versions will be determined as follows:

[0166] If the number of PDSCH transmission layers is equal to one for the first TCI state and one for the second TCI state, the redundancy versions to be applied is derived according to TABLE 21.

[0167] If the number of PDSCH transmission layers is equal to two for the first TCI state and one for the second TCI state, the redundancy versions to be applied is derived according to TABLE 22.

[0168] If the number of PDSCH transmission layers is equal to one for the first TCI state and two for the second TCI state, the redundancy versions to be applied is derived according to TABLE 23.

[0169] If the number of PDSCH transmission layers is equal to two for the first TCI state and two for the second TCI state, the redundancy versions to be applied is derived according to TABLE 24.

TABLE 21 : Applied redundancy version for multi-TRP rank 1 + 1 PDSCH layer aggregation

TABLE 22: Applied redundancy version for multi-TRP rank 2 + 1 PDSCH layer aggregation

TABLE 23: Applied redundancy version for multi-TRP rank 1 + 2 PDSCH layer aggregation

TABLE 24: Applied redundancy version for multi-TRP rank 2 + 2 PDSCH layer aggregation

[0170] In addition, if a ‘layer sub-aggregation bit’ is also defined and set= 1 to facilitate the tradeoff between capacity and redundancy, redundancy versions can be determined as follows: [0171] If the number of PDSCH transmission layers is equal to one for the first TCI state and one for the second TCI state, the redundancy versions are determined by TABLE 2 above, with n = 0 for all layers

[0172] If the number of PDSCH transmission layers is equal to two for the first TCI state and one for the second TCI state, the redundancy versions to be applied is derived according to TABLE 25.

[0173] If the number of PDSCH transmission layers is equal to one for the first TCI state and two for the second TCI state, the redundancy versions to be applied is derived according to TABLE 26.

[0174] If the number of PDSCH transmission layers is equal to two for the first TCI state and two for the second TCI state, the redundancy versions to be applied is derived according to TABLE 27.

TABLE 25: Applied redundancy version for multi-TRP rank 2 + 1 PDSCH layer sub-aggregation

TABLE 26: Applied redundancy version for multi-TRP rank 1 + 2 PDSCH layer sub-aggregation

TABLE 27: Applied redundancy version for multi-TRP rank 2 + 2 PDSCH layer sub-aggregation

[0175] Multi-TRP PDSCH Layer Aggregation with Repetition. In the case of multi-TRP transmission with inter-slot time domain repetition, a WTRU configured by the higher layer parameter PDSCH-config that indicates at least one entry contains repetitionNumber in PDSCH-TimeDomainResourceAllocation, and if two TCI states are indicated by the DCI field 'Transmission Configuration Indication' together with the DCI field 'Time domain resource assignment indicating an entry which contains repetitionNumber in PDSCH- TimeDomainResourceAllocation and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)¹, the WTRU may expect to receive multiple slot level PDSCH transmission occasions of the same TB with two TCI states used across multiple PDSCH transmission occasions in the repetitionNumber consecutive slots and the same SLIV is applied for all PDSCH transmission occasions across the repetitionNumber consecutive slots. The WTRU may expect that each PDSCH transmission occasion is limited to two transmission layers.

[0176] The first TCI state is applied to the first PDSCH transmission occasion and resource allocation in time domain for the first PDSCH transmission occasion. When the value indicated by repetitionNumber in PDSCH-TimeDomainResourceAllocation equals to two, the second TCI state is applied to the second PDSCH transmission occasion When the value indicated by repetitionNumber in PDSCH- TimeDomainResourceAllocation is larger than two, the WTRU may be further configured to enable cyclicMapping or sequenticalMapping in tciMapping.

[0177] If the number of PDSCH transmission layers is equal to one for the first TCI state or if the layer aggregation bit is set to 0, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied may be derived according to TABLE 2 above, where n is counted only considering PDSCH transmission occasions associated with the first TCI state.

[0178] If the number of PDSCH transmission layers is equal to one for the second TCI state or if the layer aggregation bit is set to 0, the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 3 above, where additional shifting operation for each redundancy version rv_s is configured by higher layer parameter sequenceOffsetforRV and n is counted only considering PDSCH transmission occasions associated with the second TCI state.

[0179] If the number of PDSCH transmission layers is equal to two for the first TCI state and if the layer aggregation bit is set to 1, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied is derived according to TABLE 28, where n is counted only considering PDSCH transmission occasions associated with the first TCI state.

TABLE 28: Applied redundancy version for multi-TRP rank 2 PDSCH layer aggregation with repetitionNumber for the first TCI state

[0180] If the number of PDSCH transmission layers is equal to two for the second TCI state and if the layer aggregation bit is set to 1 , the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 29, where additional shifting operation for each redundancy version rv_s is configured by higher layer parameter sequenceOffsetforRV and n is counted only considering PDSCH transmission occasions associated with the second TCI state

TABLE 29: Applied redundancy version for multi-TRP rank 2 PDSCH layer aggregation with repetitionNumber for the second TCI state when sequenceOffsetforRV is present

[0181] In the case of multi-TRP transmission with intra-slot time domain repetition, a WTRU is configured by the higher layer parameter repetitionscheme set to 'tdmSchemeA' and indicated DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', and when two TCI states are indicated by the DCI field ‘Transmission Configuration indication' for multi-TRP operation, the WTRU is expected to receive two PDSCH transmission occasions of the same TB with non-overlapping time domain resource allocation, where the first TCI state is applied to the first PDSCH transmission occasion. The second TCI state is applied to the second PDSCH transmission occasion, and the second PDSCH transmission occasion shall have the same number of symbols as the first PDSCH transmission occasion Both PDSCH transmission occasions shall be received within a given slot. In addition, the WTRU is not expected to receive more than two PDSCH transmission layers for each PDSCH transmission occasion. [0182] If the number of PDSCH transmission layers is equal to one for the first TCI state or if the layer aggregation bit is set to 0, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied may be derived according to TABLE 2 above, where n — 0 is applied to the first TCI state If the number of PDSCH transmission layers is equal to one for the second TCI state or if the layer aggregation bit is set to 0, the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 2, where n = 1 is applied to the second TCI state.

[0183] If the number of PDSCH transmission layers is equal to two for the first TCI state and if the layer aggregation bit is set to 1, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied is derived according to TABLE 30 below, where n = 0 is applied to the first TCI state. If the number of PDSCH transmission layers is equal to two for the second TCI state and if the layer aggregation bit is set to 1 , the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 30 below, where n = 1 is applied to the second TCI state

TABLE 30: Applied redundancy version for multi-TRP rank 2 PDSCH layer aggregation for tdmSchemeA

[0184] In the case of multi-TRP transmission with frequency domain repetition, a WTRU configured by the higher layer parameter repetition Scheme set to 'tdmSchemeA' or 'fdmSchemeB', and the WTRU is indicated with two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' and DM-RS port(s) within one CDM group in the DCI field 'Antenna Port(s)', the WTRU is not expected to receive more than two PDSCH transmission layers for each PDSCH transmission occasion.

[0185] When two TCI states are indicated in a DCI and the WTRU is set to 'fdmSchemeA', the WTRU shall receive a single PDSCH transmission occasion of the TB with each TCI state associated to a non-overlapping frequency domain resource allocation.

[0186] If the number of PDSCH transmission layers is equal to one or if the layer aggregation bit is set to 0, the redundancy version to be applied is derived according to TABLE 2, with n = 0 applied for the first and second TCI state. On the other hand, if the number of PDSCH transmission layers is equal to two and if the layer aggregation bit is set to 1 , the redundancy versions to be applied for the first and second TCI state is exemplified in TABLE 31 below.

TABLE 31 : Applied redundancy version for multi-TRP rank 2 PDSCH layer aggregation for fdmSchemeA

[0187] When two TCI states are indicated in a DCI and the WTRU is set to 'fdmSchemeB', the WTRU shall receive two PDSCH transmission occasions of the same TB with each TCI state associated to a PDSCH transmission occasion which has non-overlapping frequency domain resource allocation with respect to the other PDSCH transmission occasion. The WTRU is not expected to receive more than two PDSCH transmission layers for each PDSCH transmission occasion. In addition, the WTRU shall only expect at most two code blocks per PDSCH transmission occasion when a single transmission layer is scheduled and a single code block per PDSCH transmission occasion when two transmission layers are scheduled.

[0188] If the number of PDSCH transmission layers is equal to one for the first TCI state or if the layer aggregation bit is set to 0, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied is derived according to TABLE 2, where n = 0 is applied to the first TCI state. If the number of PDSCH transmission layers is equal to one for the second TCI state or if the layer aggregation bit is set to 0, the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 2, where n = 1 is applied to the second TCI state.

[0189] If the number of PDSCH transmission layers is equal to two for the first TCI state and if the layer aggregation bit is set to 1, and for all PDSCH transmission occasions associated with the first TCI state, the redundancy version to be applied is derived according to TABLE 32 below, where n — 0 is applied to the first TCI state. If the number of PDSCH transmission layers is equal to two for the second TCI state and if the layer aggregation bit is set to 1 , the redundancy version for PDSCH transmission occasions associated with the second TCI state is derived according to TABLE 32, where n = 1 is applied to the second TCI state.

TABLE 32: Applied redundancy version for multi-TRP rank 2 PDSCH layer aggregation for fdmSchemeB

[0190] When the WTRU receives the DCI signaling indicating the use of layer aggregation/sub-aggregation in PDSCH, the WTRU extracts multiple redundancy versions of each code block from different MIMO layers and multiple TRPs and performs HARQ combing from the multiple redundancy versions of each code block. Based on the decoding results, the WTRU then reports Ack/Nack feedback of the received transport blocks or code block groups (CBGs) to the network, as configured.

[0191] Referring to FIG. 5, according to a one embodiment, dynamic triggering of PDSCH layer aggregation is used to facilitate enhanced spatial diversity during single-TRP transmission for coexistence with high-power interferes such as radar.

[0192] As shown in FIG. 5, an example method 500 is shown for a radio access network (RAN) node, e.g., a base station/gNB, utilizing dynamic triggering of PDSCH layer aggregation according to one embodiment. The gNB determines or receives 505 information characterizing the operation of a high-power interferer such as radar. The information characterizing the operation of a radar may include, for example, AOA, frequency, bandwidth (BW), etc. of the radar emissions. In one example, the gNB identifies if 510, one or more WTRUs the gNB is serving, may encounter interference with radar transmissions based on one or more thresholds. As one example, the location of a WTRU may be considered with respect to the radar characteristics impact at the WTRU’s location, where the impact is based on comparing the radar likely characteristics at that location to one or more interference thresholds being exceeded. Next, the gNB determines 515 the rank of the PDSCH transmission(s) to the identified WTRU(s), e.g., based on a channel state information (CSI)-reference signal (RS) report provided by the WTRU. If 520, the rank of PDSCH transmission for the WTRU(s) is greater than 1, the gNB may determine to dynamically activate PDSCH layer aggregation/sub-aggregation (along with possible time domain repetition) to provide enhanced reliability and reduced latency for radar coexistence.

[0193] The gNB indicates 525 the use of PDSCH layer aggregation/sub-aggregation (along with possible time domain repetition) in the DCI signaling to the WTRU(s) identified in step 510. Multiple options of PDSCH repetition and number of repetitions can be configured via higher layer signaling and dynamically selected/disabled via DCI. [0194] Next the gNB transmits 530 multiple redundancy versions of a PDSCH codeword across multiple MIMO layers. In one embodiment, for each redundancy version, every code block of the codeword may be distributed evenly across multiple MIMO layers. In a second embodiment, the code blocks for different redundancy versions of the codeword may be mapped to different MIMO layers. In the case the radar may not likely cause any WTRU being served by the gNB interference to exceed the relevant threshold at step 510, or the rank of the PDSCH transmission at step 520 is not greater than 1 at step 520, the gNB may determine 535 not to use PDSCH layer aggregation/sub-aggregation. It should be recognized that a similar, but related inverse process may be used by the gNB to disable or stop using PDSCH layer aggregation/sub-aggregation after it was dynamically initiated, e.g., if a rank changes to less than 1 , characteristics of the radar change, the WTRU mobility changes, etc. As with any of the embodiments disclosed herein, the steps of method 500 may be modified, performed in a different order, omitted or combined with other embodiments.

[0195] Referring to FIG. 6, an example method 600 for a WTRU utilizing dynamic triggering of PDSCH layer aggregation is shown according to an embodiment, from an example perspective of a mobile device. The WTRU receives 605 the DCI signaling from the gNB indicating the use of layer aggregation/sub-aggregation for PDSCH codewords sent in a MIMO transmission. The WTRU receives 610 the MIMO transmission and extracts 615 multiple redundancy versions of each code block of a PDSCH codeword from the layers of the MIMO transmission. Next, the WTRU performs 620 HARQ combining from the multiple redundancy versions of each code block and the WTRU reports 625 ACK/NACK(s) for the transport blocks or code block groups (CBGs) to the network, as configured. In some embodiments, prior to receiving the DCI, the WTRU sends a channel state information reference signal (CSI-RS) report indicating to the base station the PDSCH MIMO rank being greater than 1. The steps of method 600 may be modified, performed in a different order, omitted or combined with other embodiments

[0196] Turning to FIG 7, an example method 700 is shown for a radio access network (RAN) node, e g., a base station/gNB, utilizing dynamic triggering of PDSCH layer aggregation according to a second solution of the embodiments. In this solution, dynamic triggering of PDSCH layer aggregation is used to facilitate enhanced spatial diversity during multi-TRP transmission for coexistence with high-power interferes such as radar. The gNB receives or determines 705 information characterizing the operation of a proximate high-power interferer such as radar. The information characterizing the operation of a radar may include, for example, AOA, frequency, BW, power level, etc. of the radar emissions.

[0197] In one example the gNB identifies if 710, one or more WTRUs the gNB is serving, may encounter interference with radar transmissions based on comparing the radar information to one or more thresholds. As one example, the location of a WTRU or TRPs may be considered with respect to the radar characteristics impact at the WTRU’s and/or TRP’s location, where the impact is based on comparing the radar characteristics at that location to one or more interference thresholds being exceeded. If any WTRU is identified in step 710, the gNB determines 715 the rank of the PDSCH transmission based on CSI-RS reporting provided by the WTRU for each TRP in the case of multi-TRP transmission. If 720, the rank is greater than 1 in any of the TRPs, the gNB may determine whether to include layer aggregation/sub-aggregation (along with possible time or frequency domain repetition) to provide enhanced reliability and reduced latency for radar coexistence

[0198] Next, the gNB may indicate 725, to a relevant WTRU identified in step 710, the use of PDSCH layer aggregation/sub-aggregation (along with possible time or frequency domain repetition) in the DCI signaling. As previously discussed, there are multiple options for the PDSCH multi-TRP repetition scheme and the number of repetitions can be configured via higher layer signaling and dynamically selected/disabled via DCI.

[0199] Next, the gNB transmits 730 multiple redundancy versions of a PDSCH codeword across multiple MIMO layers and multiple TRPs. In one embodiment, for each redundancy version, every code block of the codeword is distributed evenly across multiple MIMO layers. In a second embodiment, the code blocks for different redundancy versions of the codeword are mapped to different MIMO layers In the case the radar may not likely cause any WTRU being served by the gNB to experience interference above the threshold at step 710, or the rank of the PDSCH transmission from any TRP at step 720 is not greater than 1 , the gNB may determine 735 not to use PDSCH layer aggregation/sub-aggregation. It should be recognized that a similar, but inverse process may be used by the gNB to disable or stop using PDSCH layer aggregation/sub- aggregation after it was dynamically initiated, e.g , if a rank changes to less than 1, characteristics of the radar change, the WTRU mobility changes, etc. The steps of method 700 may be modified, performed in a different order, omitted or combined with other embodiments.

[0200] In this embodiment, similar to FIG. 6 method 600, the WTRU receives the DCI signaling indicating the use of layer aggregation/sub-aggregation in the PDSCH. The WTRU extracts multiple redundancy versions of each code block from one or more MIMO layers and multiple TRPs. The WTRU performs HARQ combining from the extracted multiple redundancy versions of each code block and reports the ACK/NACK for the transport blocks or code block groups (CBGs) to the network, as configured. Again, prior to receiving the DCI, the WTRU may send a CSI-RS report indicating a rank greater than one for any TRP in case of multi-TRP transmission.

[0201] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magnetooptical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is Claimed:

1. A method for use in a base station, the method comprising: receiving information characterizing an operation of a high-power interferer; based on the information characterizing the operation, determining that a wireless transmit receive unit (WTRU) will incur interference when receiving one or more physical downlink shared channel (PDSCH) codewords; sending, to the WTRU, a downlink control information (DCI) indicating PDSCH layer aggregation/sub-aggregation; and sending, to the WTRU, multiple redundancy versions of the one or more PDSCH codewords across two or more layers of a multiple-input multiple-output (MIMO) transmission.

2. The method of claim 1 , wherein different code blocks of each redundancy version of the one or more PDSCH codewords are distributed evenly across the two or more layers of the MIMO transmission.

3. The method of claim 1, wherein each redundancy version of the one or more PDSCH codewords is mapped to a different layer of the MIMO transmission

4. The method of claim 1 , wherein the sending of multiple redundancy versions of the one or more PDSCH codewords across two or more layers of the MIMO transmission is performed in cooperation with multiple transmit receive points (TRPs).

5. The method of claim 1, wherein prior to sending the DCI, the method further comprises: determining to use PDSCH layer aggregation/sub-aggregation based on a channel state information reference signal (CSI-RS) report from the WTRU indicating a PDSCH MIMO rank greater than 1.

6. The method of claim 5, wherein the CSI-RS report indicates the PDSCH MIMO rank is greater than 1 for at least one transmit receive point (TRP).

7. The method of claim 1 , wherein the DCI further indicates one or more of a time domain repetition or a frequency domain repetition of the one or more PDSCH codewords.

8. The method of claim 1, wherein determining the WTRU will incur interference from the high-power interferer comprises comparing the information characterizing the operation of the high-power interferer against one or more interference thresholds.

9. The method of any one of claims 1-8 wherein the high-power interferer comprises a radar.

10. A base station comprising: a transceiver; and a processor in communication with the transceiver, wherein the transceiver and the processor are configured to: receive information characterizing an operation of a high-power interferer; based on the information characterizing the operation, determine a wireless transmit receive unit (WTRU) will incur interference from the high-power interferer in receiving one or more physical downlink shared channel (PDSCH) codewords; send, to the WTRU, a downlink control information (DCI) indicating PDSCH layer aggregation/sub- aggregation; and send, to the WTRU, multiple redundancy versions of the one or more PDSCH codewords across two or more layers of a multiple-input multiple-output (Ml MO) transmission.

11. The base station of claim 10, wherein different code blocks of each redundancy version of the one or more PDSCH codewords are distributed evenly across the two or more layers of the MIMO transmission.

12. The base station of claim 10, wherein each redundancy version of the one or more PDSCH codewords is mapped to a different layer of the MIMO transmission

13. The base station of claim 10, wherein the sending of multiple redundancy versions of the one or more PDSCH codewords across two or more layers of the MIMO transmission is performed in cooperation with multiple transmit receive points (TRPs).

14. The base station of claim 10, wherein prior to sending the DCI, the transceiver and the processor are further configured to: determine to use PDSCH layer aggregation/sub-aggregation based on a channel state information reference signal (CSI-RS) report from the WTRU indicating a PDSCH MIMO rank greater than 1.

15. The base station of claim 14, wherein the CSI-RS report indicates the PDSCH MIMO rank is greater than 1 for at least one transmit receive point (TRP).

16. A method for use by a wireless transmit receive unit (WTRU), the method comprising: receiving, from a network, downlink control information (DCI) indicating use of layer aggregation/sub-aggregation in a multiple-input multiple-output (MIMO) transmission of one or more physical downlink shared channel (PDSCH) codewords; receiving, from the network, the MIMO transmission; extracting code blocks of multiple redundancy versions of the one or more PDSCH codewords from each layer of the received MIMO transmission; performing hybrid automatic repeat request (HARQ) combining of the extracted code blocks of the multiple redundancy versions of the one or more PDSCH codewords; and based on the HARQ combining, reporting, to the network, an acknowledgement (ACK) or negative ACK (NACK) for transport blocks or code block groups (CBGs)

17. The method of claim 16, wherein the MIMO transmission is received from multiple transmit receive points (TRPs).

18. The method of claim 16, wherein the MIMO transmission is received from a base station.

19. The method of claim 16, wherein prior to receiving the DCI, the method further comprises: sending, to the network, a channel state information reference signal (CSI-RSI) report indicating a PDSCH MIMO rank greater than 1 for at least one transmit receive point (TRP).

20. The method of claim 16, wherein the MIMO transmission has between 2 to 8 layers.