Methods and apparatuses for multi-TRP transmission in hst scenarios

Abstract

To provide a method and a wireless transmit / receive unit (WTRU) for efficiently transmitting reference signals in a high-speed train scenario.SOLUTION: In a communication system, a WTRU receives first configuration information indicating a first temporal TRS density of a tracking reference signal (TRS) from a Transmit / Receive Point (TRP), receives second configuration information indicating a second temporal TRS density of the TRS, receives signaling information from a base station indicating whether to use the first configuration information or the second configuration information, and selects the first configuration information or the second configuration information for receiving the TRS based on the signaling information.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 976,158, filed February 13, 2020, U.S. Provisional Patent Application No. 63 / 061,293, filed August 5, 2020, and U.S. Provisional Patent Application No. 63 / 094,745, filed October 21, 2020, the contents of each of which are incorporated herein by reference. [Background technology]

[0002] In New Radio (NR), Multi-Transmit / Receive Point (M-TRP) operation is supported with a downlink transmission-first focus, and therefore an NR WTRU can receive and process multiple NR Physical Downlink Control Channels (PDCCHs) and NR Physical Downlink Shared Channels (PDSCHs).

[0003] In NR Release 16, M-TRP transmission was developed to support M-TRP transmission of the downlink shared data channel for Enhanced Mobile Broadband (eMBB) and Ultra Reliable Low Latency Communication (URLLC) scenarios. To enhance the reliability and robustness of downlink data transmission for URLLC, four different transmission schemes for the PDSCH have been agreed upon. The supported mechanisms are based on the use of additional resources in the spatial, frequency, and time domains. Depending on the scheme employed, the additional resources can be used to enable a lower code rate for the transmission or to support repetition of the original transmission.

[0004] NR Release 17 may support enhancements to both Frequency Range 1 (FR1) and Frequency Range 2 (FR2) operation. As one goal of NR Release 17, the reliability and robustness enhancements developed for the PDSCH in Release 16 may be extended to other physical channels, such as the PDCCH, PUSCH, and PUCCH. Such enhancements may leverage the use of M-TRP or multi-panel capabilities. Furthermore, Quasi Co-Location (QCL) and Transmission Configuration Indicator (TCI) related enhancements may be targeted to enable inter-cell M-TRP with multiple DCI-based multi-PDSCHs. Also, beam management aspects not studied in Release 16 may be developed. Summary of the Invention

[0005] A method and apparatus can receive zone configuration information associated with one or more zones having one or more zone identifiers (zone ids). For each zone id of the zone ids, the configuration information can indicate one or more of a beam reference signal (BRS), a set of transmission configuration indicator (TCI) states for receiving a physical downlink shared channel (PDSCH) transmission, a search space, a control resource set (CORESET) configuration, or uplink resources. The method can further include determining a zone id of the one or more zone ids based on measurements of the one or more BRSs indicated via the configuration information. An indication of the determined zone id can be transmitted to the base station using uplink resources associated with the zone id. [Brief explanation of the drawings]

[0006] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate similar elements and in which: [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 2] 1 illustrates two options for downlink M-TRP operation in which a Primary TRP (P-TRP) and a Secondary TRP (S-TRP) communicate with the WTRU. [Figure 3] We present a High Speed Train Single Frequency Network (HST-SFN) scenario in which cluster deployments of M-TRPs can be spread along the track path. [Figure 4A] 1 illustrates an exemplary M-TRP configuration for a High Speed Train (HST) scenario. [Figure 4B] 1 illustrates a procedure for determining the transmission configuration indicator (TCI) state using zone configuration. [Figure 5] An exemplary scenario is shown in which odd-numbered TRPs are located in the north of the orbit with beams pointing south, and even-numbered TRPs are located in the south of the orbit with beams pointing north. [Figure 6] 1 illustrates an embodiment of a TRP-based frequency offset pre-compensation scheme. [Figure 7] 1 is an example of M-TRP SFN transmission with Doppler compensation. [Figure 8]1 is a diagram of zero-power and non-zero-power demodulation reference signal (DM-RS) configurations for a physical downlink control channel (PDCCH) transmission having an orthogonal frequency division multiplexing (OFDM) symbol duration. [Figure 9] 1 is a diagram of a first zero-power and non-zero-power DM-RS configuration for PDCCH transmission with two OFDM symbol durations. [Figure 10] FIG. 10 is a diagram of a second zero-power and non-zero-power DM-RS configuration for PDCCH transmission with two OFDM symbol durations. [Figure 11] 1 is a diagram of a first zero-power and non-zero-power DM-RS configuration for a PDCCH transmission having a 3 OFDM symbol duration. [Figure 12] 10 is a diagram of a second zero-power and non-zero-power DM-RS configuration for PDCCH transmission with a three OFDM symbol duration configuration. FIG. [Figure 13] 1 is a diagram of an orthogonal cover code (OCC)-based DM-RS configuration for PDCCH transmission with 2 OFDM symbol duration. DETAILED DESCRIPTION OF THE INVENTION

[0007] 1A illustrates an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0008] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of 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 user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a mobile phone, 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 (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), a consumer electronic device, a device operating in a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a WTRU.

[0009] The communications system 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 communications networks, such as the CN 106, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNodeB (eNode B, eNB), a home NodeB, a home eNodeB, a next generation NodeB (gNB) such as a gNode B (gNode B, gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each shown 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.

[0010] 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, etc. The base station 114a and / or 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 licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In one 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, using beamforming to transmit and / or receive signals in desired spatial directions.

[0011] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the 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).

[0012] 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, etc. For example, the base stations 114a of 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).

[0013] In one 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-APro).

[0014] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0015] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access, e.g., using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0016] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), GSM Evolution (Enhanced Data rates for GSM Evolution, EDGE), GSM EDGE (GERAN), or the like.

[0017] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a location such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. 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 one 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 establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-APro, NR, etc.). 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 need to access the Internet 110 through the CN 106.

[0018] The RAN 104 may communicate with the CN 106, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 and / or CN 106 may communicate directly or indirectly with other RANs that use the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] 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 other networks 112. The PSTN 108 may include a public switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs that may use the same RAT as the RAN 104 or a different RAT.

[0020] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that can use cellular-based wireless technology and a base station 114b that can use IEEE 802 wireless technology.

[0021] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, 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. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0022] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0023] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one 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 understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0024] 1B 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.

[0025] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0026] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. 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 home computer (not shown).

[0027] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0028] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may obtain location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0029] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), 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, etc. The peripherals 138 may include one or more sensors. The sensor 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.

[0030] The WTRU 102 may include a full-duplex radio for transmitting and receiving some or all of the signals (e.g., associated with a particular subframe on both the UL (e.g., for transmission) and DL (e.g., for reception)) simultaneously and / or together. The full-duplex radio may include an interference management unit for reducing and or substantially eliminating self-interference through hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmitting and receiving some or all of the signals (e.g., associated with a particular subframe on either the UL (e.g., for transmission) or DL (e.g., for reception)).

[0031] 1C is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 may also communicate with the CN 106.

[0032] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, and 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.

[0033] 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, user scheduling, etc. in the UL and / or DL. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0034] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing elements are shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0035] 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 function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c. 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.

[0036] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during inter-eNode B handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0037] The SGW 164 may be connected to a 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.

[0038] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Furthermore, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may use a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0040] In a representative embodiment, the other network 112 may be a WLAN.

[0041] A WLAN in infrastructure Basic Service Set (BSS) mode may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP and transmitted to the respective destination. Traffic between STAs within a BSS may be transmitted, for example, through the AP, where the source STA may send traffic to the AP, which may deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted between (e.g., directly between) a source STA and a destination STA via a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad hoc" communication mode.

[0042] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a dynamically configured width. The primary channel may be the operating channel of the BSS and may be used by 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 an 802.11 system. With CSMA / CA, STAs (e.g., all STAs), 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.

[0043] High Throughput (HT) STAs may, for example, use 40 MHz wide channels for communication via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0044] A Very High Throughput (VHT) STA may support channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. 40 MHz and / or 80 MHz may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to the Medium Access Control (MAC).

[0045] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter-type control / machine-type communications (MTC), such as MTC devices in macro coverage areas. MTC devices may have limited capabilities, including, for example, support for (e.g., only support for) specific and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0046] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be configured and / or limited by the STA among all STAs operating in the BSS that support the minimum bandwidth operating mode. In an 802.11ah example, the primary channel can be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) the 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) configuration can depend on the conditions of the primary channel. For example, if the primary channel is busy, a STA (that only supports 1 MHz mode of operation) transmitting to the AP may cause all of the available frequency bands to be considered busy, even if most of the available frequency bands are idle.

[0047] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz depending on the country code.

[0048] 1D is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using NR radio technology. The RAN 104 may also communicate with the CN 106.

[0049] The RAN 104 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to transmit and / or receive signals to the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may, for example, transmit wireless signals to and / or receive wireless signals from the WTRU 102a using multiple antennas. In one embodiment, the gNBs 180a, 180b, and 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 an unlicensed spectrum, and the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0050] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with 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 the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including varying numbers of OFDM symbols and / or varying lengths of absolute time).

[0051] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. The non-standalone configured WTRUs 102a, 102b, 102c may communicate with and connect to gNBs 180a, 180b, 180c while also communicating with and connecting to another RAN, such as eNode-Bs 160a, 160b, 160c. For example, the 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 a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0052] 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 for network slicing, DC, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0053] 1D 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 shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] 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 function as a control node. For example, the AMF 182a, 182b may be responsible for user authentication of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of the SMF 183a, 183b for registration, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the 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, etc. The AMFs 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.

[0055] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 106 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 106 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions, such as managing and assigning WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0056] The UPFs 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 UPFs 184, 184b may perform other functions such as packet routing and forwarding, user plane policy enforcement, support for multi-homed PDU sessions, handling user plane QoS, DL packet buffering, mobility anchoring, etc.

[0057] The CN 106 may facilitate communication with other networks. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the local DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0058] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices 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 simulate network and / or WTRU functions.

[0059] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation devices may be directly coupled to another device for the purpose of testing and / or performing tests using over-the-air wireless communication.

[0060] One or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, e.g., one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0061] In Release 15NR, one or more control resource sets (CORESETs) may be configured per bandwidth part (BWP), and each CORESET may be configured with one or more beam reference signals via Radio Resource Control (RRC) signaling. A beam reference signal may be either a Non-Zero Power Channel State Information Reference Signal (NZP-CSI-RS) that may include a NZP-CSI-RS resource ID, or a Synchronization Signal Block (SSB) signal that may include an SSB index. The beam reference signal may be indicated in the configured beam reference signal via a Medium Access Control (MAC) Control Element (CE) for monitoring the PDCCH search space associated with the CORESET, and the beam reference signal index may be signaled via a Transmission Configuration Indicator (TCI) status.

[0062] One or more TCI states may be configured for a CORESET, and each TCI state may include quasi-co-location (QCL) information. The QCL information may include beam reference signal information. The TCI state may be indicated for the CORESET via the MAC-CE in the configured TCI state to indicate a beam reference signal for monitoring the PDCCH search space associated with the CORESET.

[0063] One or more PDCCH search spaces may be associated with a CORESET, and the WTRU may determine a beam, such as a spatial Rx beam, for monitoring the PDCCH search space based on the determined beam of the associated CORESET for the PDCCH search space.

[0064] The associated beam reference signal (BRS) may be denoted as a reference signal index with QCL type D. BRS may be used interchangeably with the terms beam RS, CSI-RS, SSB, SSB / PBCH block, tracking reference signal (TRS), and sounding reference signal (SRS).

[0065] In NR, the time and frequency resources that may be used by the WTRU to report CSI may be controlled by a 5G NodeB or next generation NodeB. The CSI may consist of or consist of a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), a SS / PBCH block resource indicator (SSBRI), a layer indicator (LI), a rank indicator (RI), or a Layer 1 reference signal receive power (L1-RSRP).

[0066] The framework may operate based on three main configuration objects: CSI-ReportConfig, CSI-ResourceConfig, and one or more lists of trigger conditions. CSI-ReportConfig may contain N≧1 reporting configurations that capture details related to the measurement reporting mechanism. CSI-ResourceConfig may contain M≧1 different resource configurations that may be combined with at least one of the N reporting configurations.

[0067] There may be two options for the list of trigger states: CSI-AperiodicTriggerStateList and CSI-SemiPersistentOnPUSCH-TriggerStateList, each of which may contain at least one trigger state associated with a defined CSI-ReportConfigs configuration.

[0068] 2 shows two example scenarios 200, 220 for downlink M-TRP operation. In the first scenario 200, a primary TRP (P-TRP) 202 and a secondary TRP (S-TRP) 204 communicate with a WTRU 206. A single NR-PDCCH transmission 208 received from the P-TRP 202 schedules a single NR-PDSCH transmission, with separate layers 210, 212 transmitted from separate TRPs 202a, 202b.

[0069] In a second scenario, the P-TRP 222 and S-TRP 224 are used to schedule transmissions to the WTRU 226. In this scenario, multiple NR-PDCCH transmissions 228, 230 can each schedule a respective NR-PDSCH transmission 232, 234, with each NR-PDSCH transmission being transmitted from a separate TRP 232, 234. The NR specification can support, for example, two NR-PDSCHs and two NR-PDCCHs. An aspect of NR R-17 MIMO may be to apply the M-TRP concept to support, for example, a high-speed train (HST) scenario in a single-frequency network (HST-SFN).

[0070] FIG. 3 illustrates an HST-SFN scenario 300 in which an M-TRP deployment can be spread along a track path 302 to provide service to a train 304. A first cluster of TRPs can include TRPs 306-310 connected to a baseband unit (BBU) 312. A second cluster of TRPs can include TWPs 314-318 connected to a BBU 320. A BBU can refer to a unit that handles the baseband of a communication system. A typical wireless communication station consists of a BBU and one or more remote radio units. These remote radio units are shown as TRPs in FIG. 3. The baseband units can be connected to the TRPs via optical fibers and can be responsible for communication over the physical interface.

[0071] Embodiments directed to determining TCI status based on zones are described herein. One or more zones may be defined, configured, or used in an HST-SFN network. A zone may be configured or determined based on the geographic coordinates (e.g., longitude and latitude) of a WTRU, and the zone may be associated with zone identification information (e.g., zone id). In such embodiments, one or more procedures may be implemented.

[0072] In some embodiments, for example, the WTRU may determine an associated zone (or zone id) based on the geographic coordinates of the WTRU (e.g., the geographic coordinates of the WTRU are within a corresponding range).

[0073] In some embodiments, a WTRU may determine an associated zone (or zone id) based on an associated cell identity (or TRP identity). The zone may be configured based on a zone size (e.g., x meters of longitude and y meters of latitude). The zone size may be configured or indicated in higher layer signaling (e.g., master information block (MIB), SIB, RRC, or MAC-CE). The zone size may be determined based on one or more WTRU-specific parameters (e.g., WTRU speed, direction of movement, WTRU identity) and / or system parameters (e.g., cell identity, numerology).

[0074] In some embodiments, the zones may be configured based on the radio coverage of the cells. For example, the WTRU may determine the zones based on downlink measurements of one or more TRPs or one or more beam reference signals from the cells. Hereinafter, zones may be used interchangeably with area, location, and positioning.

[0075] In some embodiments, the WTRU may receive a configuration of an association between a TCI state (or TCI state group) and a zone. For example, one or more TCI states may be associated with a zone (or zone id), and the association information may be configured via higher layer signaling. In such a scenario, one or more of the following procedures may be performed. For example, the WTRU may determine a TCI state for downlink reception and / or uplink transmission based on a determined zone id. For example, the WTRU may first determine a zone id based on the WTRU's geographical coordinates, and the WTRU may determine a TCI state for downlink reception (e.g., PDCCH and / or PDSCH) and / or uplink transmission (e.g., PUCCH, PUSCH, SRS, PRACH) based on the determined zone id. A corresponding beam reference signal (e.g., SSB index, CSI-RS index, SRS resource index) of the TCI state may be determined based on the zone id. For example, the WTRU may receive a TCI state of a DCI for downlink or uplink transmission, and the WTRU may interpret the TCI state differently based on the determined zone id. When a first zone ID is determined, a first beam reference signal can be used for the TCI state, and when a second zone ID is used, a second beam reference signal can be used for the TCI state. One or more N-bit TCI state fields can be used in downlink or uplink transmission of DCI scheduling, and the N-bit TCI state field can be associated with a set of TCI states, and the set of TCI states can be determined based on the determined zone ID. For example, when a first zone ID is determined, a first set of TCI states can be used for the N-bit TCI state field, and when a second zone ID is determined, a second set of TCI states can be used for the N-bit TCI state field.

[0076] In some embodiments, the WTRU may indicate or report its determined zone id to a NodeB (e.g., gNB). For example, the WTRU may send or report the determined zone id when the zone id changes. For example, the WTRU may report an updated zone id when the WTRU detects a change in the associated zone id. In some cases, the zone id update report may be indicated in the PUSCH, PUCCH, MAC-CE, or RRC. In some cases, each zone id may be associated with an uplink channel (e.g., a PRACH, a PRACH sequence, a PUCCH resource, a PUSCH resource, an SRS resource), and the WTRU sends the associated uplink channel based on the determined zone id.

[0077] In some embodiments, a CORESET may be configured with one or more TCI states, one of which may be determined or used at time to monitor an associated PDCCH search space. The WTRU may determine one of the TCI states of the CORESET based on a determined zone ID. In some embodiments, the TCI state associated with a zone ID may be configured via higher layer signaling.

[0078] In some embodiments, the WTRU may monitor a subset of the PDCCH search space that may be associated with one or more CORESETs that correspond to the determined zone id. For example, the WTRU may be configured with one or more CORESETs, and each CORESET may be associated with one or more zone ids, and thus the subset of CORESETs may be determined based on the determined zone id.

[0079] Hereinafter, the terms TCI state may be used interchangeably with spatial association, QCL association, QCL type D, and / or beam.

[0080] 4A illustrates an HST-SFN scenario 400 in which a cluster deployment of M-TRPs, including TRPs 404-408 and TRPs 412-416, may be spread along the track path of a train 402. To increase robustness and also reduce signaling associated with handovers, the HST-SFN scenario 400 may employ an architecture based on a cluster deployment of M-TRPs. Accordingly, embodiments and enhancements related to the QCL assumption, the TCI framework, the control channel design, and the CSI framework may be advantageous to support the HST-SFN deployment scenario.

[0081] In this example of an M-TRP configuration for an HST scenario, the WTRU can determine the zone in which it is located and can determine associated zone-based spatial parameters associated with the received TCI state. This can be performed to receive data within the zone. The zone identification and zone-based parameters can be used to reduce signaling overhead in the HST scenario.

[0082] For example, if the WTRU is located on a train 402 and is served by one or more of the TRPs 404-408, the WTRU may determine a zone id of n 410. If the WTRU is served by one or more of the TRPs 412-416, the WTRU may determine a zone id of m 418. The WTRU may be configured with one or more first beam RSs, a set of TCI conditions, an SS / CORESET configuration, and uplink resources for the n zone id 410. For the m zone id, the WTRU may be configured with a second set of configuration parameters including one or more second beam RSs, a set of TCI conditions, a second SS / CORESET, and second UL resources. The zone id may be determined from among the configured zone ids based on one or more BRS measurements from at least one BRS configured for each zone id and the geographic coordinates of the WTRU.

[0083] 4B is a flowchart 420 illustrating a procedure for determining TCI states using zone configurations. The procedure can be summarized as follows: A WTRU may receive one or more zone configurations (e.g., defined by geographic coordinates), each identified by an ID, e.g., a zone id (422). For each zone id, the WTRU may receive at least one beam reference signal (BRS), a set of TCI states for PDSCH reception, a search space / CORESET configuration, and / or uplink resources (424). The WTRU may determine a zone id from among the configured zone ids based on measurements of one or more BRSs from among the at least one BRS configured for each zone id and the WTRU's geographic coordinates (426).

[0084] The WTRU may monitor the search space or CORESET according to the search space or CORESET configuration of the determined zone id for the PDCCH and receive and / or decode DCI on the PDCCH (428). The PDCCH may include an indication of the TCI state for PDSCH reception. The WTRU may determine (430) a reference signal (RS) associated with the received TCI state based on the zone id. The WTRU may receive (432) a transmission using the PDSCH, e.g., by using an associated PDSCH DMRS that is QCL'd with the determined RS, and may indicate (434) the determined zone id to the gNB using uplink resources configured for the zone id.

[0085] In one embodiment, one enhancement may involve efficient updating of TCI / QCL information. In NR, the quasi-co-location (QCL) relationship may refer to the spatial quasi-co-location of reference signals. The QCL relationship may be expressed in terms of delay spread, mean delay, Doppler spread, Doppler shift, or spatial Rx parameters. The TCI may carry information regarding the reference signal antenna port to which a particular PDCCH or PDSCH (DMRS) antenna port is quasi-located ("QCLed").

[0086] In some embodiments, a WTRU may be configured with up to 64 TCI states. A subset of the TCI states assigned to the WTRU may be signaled to the WTRU through RRC signaling in the corresponding CORESET. A particular TCI state may be dynamically signaled by the WTRU through MAC signaling. A TCI state may consist of at least one combination of a serving cell, a bandwidth portion identity, and at least one reference signal. The at least one reference signal may be a CSI-RS or SSB. The WTRU may assist in receiving PDCCH or PDSCH transmissions assuming a quasi-co-location relationship exists between ports of such reference signals and DM-RS ports. This may be, for example, to set or select spatial filters and to estimate timing and Doppler spread and / or shift. Configuring multiple reference signals for TCI states may enable the WTRU to select the most appropriate spatial filter in scenarios where a channel (e.g., PDCCH or PDSCH) is received from multiple TRPs or beams in an SFN manner. Such a TCI state may be referred to as a “multi-beam” TCI state.

[0087] Alternatively, the WTRU may be provided with a group of TCI states instead of a single TCI state for purposes of PDCCH or PDSCH reception, and the WTRU may assume that the same information is transmitted on all DM-RS ports that are quasi-co-located with the reference signal port of each TCI state of the group. Without loss of generality, a multi-beam TCI state or a group of TCI states may be referred to as a "TCI information vector" as described herein.

[0088] In an HST-SFN network, a WTRU may be served by more than one TRP at any given time, substantially as shown and described above with respect to Figure 2. Due to the high mobility of HST trains, TCI information may require continuous updates as the train progresses through a cluster of TRPs.

[0089] The path may be partitioned and a TCI information vector may be defined. In some embodiments, the WTRU may assume that the entire orbital path is partitioned into several zones, each zone hosting at least one SFN M-TRP deployment, and each M-TRP deployment having two or more TRPs connected to a single baseband unit (BBU).

[0090] In some embodiments, the WTRU can determine information about the downlink reference signal, e.g., beam and DMRS port, from the configured TCI vector that is configured for that zone. In some embodiments, the WTRU may be configured with different types of TCI configurations for each zone.

[0091] In some embodiments, the WTRU can determine the TCI information for each TRP of a zone from a TCI information vector defined per TRP and per bandwidth portion. The length of the TCI information vector can be equal to the number of TRPs per zone. Each entry in the information vector can have multiple values corresponding to different configurations or operating modes of the TRP. In an example embodiment, multiple values can exist, and the WTRU can determine the TCI information for different beams of the TRP from different configured values of the entry. For example, the WTRU can determine the TCI information for opposite directions of the TRP, such as downlink versus uplink beams for an HST train, from different configured values of the entry indexed to the TRP. In some cases, instead of having multiple values per entry, the WTRU can assume that different classes or types of TCI information vectors can exist.

[0092] In one embodiment, the WTRU may be configured with two or more TCI information vectors, each of which may have a different length than the other vectors. The WTRU may identify each TCI information vector using an index.

[0093] Disclosed herein are embodiments directed to an index of the TCI information vector. In some embodiments, the WTRU may determine the TCI information vector of a zone in a dynamic or semi-static manner.

[0094] In dynamic mode, the WTRU may receive an information element to determine the TCI information vector of a zone having a DCI or MAC CE. The WTRU may decode the received information element to determine the index of the TCI information vector. The index may determine the TCI information vector of the proximity zone. The access zone may start immediately after the current TRP or at the nth TRP after the current TRP, where n may be a configured value. In another embodiment, in addition to a set of TCI information vectors, the WTRU may be configured with a sequence of indices representing the index of the TCI vector for each zone. The WTRU may receive a single-bit DCI or MAC-CE to indicate an increment in the configured sequence to point to the next zone. The access zone may start immediately after the current TRP or at the nth TRP after the current TRP, where n may be a configured value.

[0095] In semi-static mode, in addition to the set of TCI information vectors, the WTRU may be configured with other information to aid in determining the TCI information vector for each zone. In some embodiments, the WTRU may be configured with a geolocation table that associates some or all zones with an index, where the index represents a TCI information vector. The WTRU can determine the TCI information for a zone by comparing the geolocation with the configured index in the table. Alternatively, the WTRU may be configured with a sequence of indexes, where each index represents a TCI information vector. The WTRU can determine the TCI information vector for a zone by looking up the configured sequence of indexes and following the sequence. In another embodiment, the WTRU may periodically use one or more of the configured TCI information vectors across all zones.

[0096] Disclosed herein are embodiments directed to conditional reconfiguration of a set of TCI information vectors or a set of TCI states. In some embodiments, to facilitate fast large-scale reconfiguration, a WTRU may apply conditional reconfiguration of a set of TCI states or a set of TCI information vectors based on the results of at least one measurement. For example, a WTRU may be configured with a current set of TCI states or TCI information vectors and at least one target set of TCI states or TCI information vectors. Only the current set of TCI states or TCI information vectors may be applicable for PDCCH and PDSCH reception at any given time. A WTRU may be configured with at least one measurement configuration for each target set of TCI states or information vectors. Upon triggering a measurement report based on such configuration, the WTRU may reconfigure the current set of TCI states or TCI information vectors as the corresponding target set. The WTRU may apply a default or initial TCI state or TCI information vector from among the reconfigured set of TCI states or TCI information vectors for decoding the PDCCH and PDSCH immediately after the reconfiguration. The WTRU may also be signaled an SRS configuration of interest for each set of interests in the TCI state or information vector, and may reconfigure the SRS according to the corresponding set of interests.

[0097] In some embodiments, the WTRU may report a subset of at least one TCI information vector from the set of TCI information vectors so that performance may be maximized. The WTRU may report this information at the physical layer, such as via a new type of CSI or by the MAC CE. The WTRU may trigger a report when there is a change in the best TCI information vector.

[0098] As of NR Release 16, at least four different QCL types may be defined: Type A, B, C, and D. The QCL information may define which properties of a channel observed by one set of antenna ports may hold accurately for another set of antenna ports. For example, QCL Type C may indicate that only the mean delay and Doppler shift values observed by one set of antenna ports may be assumed for its QCLed counterpart (and vice versa). However, if two sets of antenna ports are QCLed with Type A, then besides the mean delay and Doppler shift, both channels may be assumed to experience similar Doppler spread and delay spread values.

[0099] In a multi-TRP transmission scenario, when a WTRU traveling at high speed receives transmissions from multiple TRPs from opposite directions of the WTRU's path of travel, the Doppler shift experienced for each transmission may be different. For example, when a high-speed WTRU is between two TRPs, it may experience positive Doppler from one TRP and negative Doppler from another TRP. In some cases, a high-speed WTRU traveling in one direction from one TRP to another may receive an indication that the transmit ports from the involved TRPs may impose opposite Doppler shifts.

[0100] In some embodiments, a fast WTRU may receive such indications for transmit ports in different panels of the same TRP, for example, so that as the WTRU passes through the TRP it knows how to efficiently adapt from a positive to a negative Doppler shift.

[0101] The WTRU may receive new QCL configuration information, including information about a transmit port that provides an opposite Doppler shift for the high-speed WTRU. For example, one or more QCL configurations for the high-speed WTRU in a multi-TRP system may be considered. Such configurations may include QCL-Type A_n, which may specify an opposite Doppler shift, Doppler spread, mean delay, and delay spread; QCL-Type B_n, which may specify an opposite Doppler shift and Doppler spread; QCL-Type C_n, which may specify an opposite Doppler shift and mean delay; QCL-Type E_n, which may specify an opposite Doppler shift and delay spread; and QCL-Type F_n, which may specify an opposite Doppler shift.

[0102] In some embodiments, the WTRU may not receive a new set of QCL information as shown above. Instead, the WTRU may receive a new implicit or explicit information element (IE) to assist the WTRU in determining the Doppler relationship between the two sets of transmit ports and interpreting this QCL information. In some embodiments, other than receiving the existing Rel-16 QCL information, the WTRU may receive an IE, for example, a single-bit configuration, indicating the value of the opposite Doppler shift imposed by the indicated QCL-bearing transmit port. In some embodiments, the indicated IE may be part of an RRC configuration and may be done per zone or cluster of the TRP. In some embodiments, the IE may be dynamically indicated by the MAC CE or DCI.

[0103] The control channel may be improved to support HST. In a high-speed train (HST) scenario, a group of WTRUs may have very high mobility. Therefore, CORESET's existing RRC-plus-MAC-CE based beam decision may not provide sufficient robustness for control channel coverage due to the resulting slow beam switching. Considering that a network component such as a gNB may know the speed and direction of movement of a group of WTRUs, one or more of the following mechanisms may be used by the network to improve the reliability of the control channel in the HST scenario.

[0104] For example, one mechanism can anticipate beam directions for a group of WTRUs, which can improve Tx-Rx beam pairing accuracy since the gNB does not need to wait for beam measurement reports from the WTRUs. Another mechanism can apply common beam control for a group of WTRUs, which can reduce beam switching control signaling overhead and latency. Another mechanism can involve, for example, determining whether a WTRU belongs to a group for group-based beam management.

[0105] The beams used for one or more CORESETs may be determined in an HST scenario. In some embodiments, one or more beam reference signals (BRS) may be used or configured, and each beam reference signal (BRS) may be configured with a BRS index. The gNB may configure a set of BRS indices that may be associated with a CORESET. For example, a CORESET may have multiple associated BRS indices, and one of the BRS indices may be determined based on a time index. For example, the time index may include at least one of a subframe number, a slot number, an SFN number, a time window number, or a symbol number.

[0106] In some cases, the WTRU may determine a BRS for the CORESET, and the determined BRS may be valid within a particular time window. A time window may be a set of consecutive OFDM symbols, slots, subframes, radio frames, or hyperframes. For example, if N time windows are configured, defined, or used, each time window may be configured with a BRS for the CORESET. The WTRU may determine a BRS index within the configured BRS indexes for monitoring one or more search spaces associated with the CORESET based on the time window or time window index.

[0107] A set of BRS indices may be configured for the CORESET, and the set of BRSs may be indexed in increasing order. For example, if N BRSs are configured, the set may be BRS1, BRS2, ..., BRS N The first BRS index k may be expressed as: k = (x, m) / (x, m). The first BRS index may be determined for a time window based on BRS measurements. For example, the WTRU may determine a first BRS index for a first time slot based on RSRP measurements of configured BRSs. The BRS with the highest RSRP may be determined as the first BRS index. If the first BRS index is x, the next BRS index for the next time window may be determined based on a predetermined order. For example, (x+1) modulo N may be used as the BRS index of the CORESET in the next time window. The BRS index k for time window m may be determined as a function of the first BRS index x selected for the first time window and time window index m. The WTRU reports the first BRS index to the gNB, and may use the reported BRS index and subsequent BRS indices once the WTRU receives confirmation from the gNB.

[0108] In the embodiments described throughout, the term beam reference signal (BRS) may be used interchangeably with TCI state, TCI state id, QCL information, NZP-CSI-RS-resource id, and SSB index.

[0109] Beams may be determined for one or more CORESETs using a zone-based beam approach. In some embodiments, one or more BRSs may be used or configured for a CORESET. One or more of the beam reference signals may be determined for a CORESET in a slot for monitoring one or more associated search spaces, and the WTRU may determine the BRS based on the WTRU's geographic location.

[0110] In one embodiment, one or more zones may be defined, configured, or used, and each zone may consist of a range of longitude and latitude in a map. The WTRU may determine the corresponding zone based on its current geographic location, for example, via global positioning satellite signaling. The configured zones may not overlap in terms of longitude and latitude in the map, and therefore there may be no ambiguity in determining the zone for a given geographic location. One or more zones may be configured based on one or more characteristics.

[0111] For example, a zone size may be composed of a longitude range x and a latitude range y, where x and y may be expressed in meters. Thus, the zone size may be a longitude of x [m] and a latitude of y [m]. Each zone may have an associated zone ID. For example, a zone ID may be assigned longitude first and then latitude in increasing order (or vice versa). A zone size may be configured using parameters x, y, and z, where z may be the size of the zone in altitude. Thus, a zone size may be represented by a longitude of x [m], a latitude of y [m], and an altitude of z [m]. Each zone may have an associated zone ID and may be assigned longitude first, then latitude, and then altitude in increasing order, or may be assigned in another order, for example, latitude → longitude → altitude. Zones may be configured via higher layer signaling, such as RRC, MAC-CE, or broadcast signaling, such as MIB or SIB.

[0112] In some embodiments, the WTRU may be configured with one or more zones, and each zone may be associated with a beam or BRS. The determined beam may be at least one of an Rx beam (or spatial Rx parameters) for receiving downlink signals, such as PDCCH or PDSCH transmissions, a Tx beam (or spatial Tx parameters) for transmitting uplink signals, such as PUSCH or PUCCH transmissions, and sidelink signals, such as PSSCH, PSCCH, or PSFCH transmissions. One or more scenarios may apply.

[0113] For example, the WTRU may receive an association between a zone id and a beam reference signal. The association information may be configured via one or more of higher layer signaling, such as MAC-CE or RRC, broadcast signaling, such as MIB or SIB, or dynamic signaling, such as via DCI.

[0114] The WTRU may determine a zone id for monitoring one or more search spaces or for receiving scheduled PDSCH transmissions within slots associated with the CORESET. The CORESET may initially be configured with TCI states for determining beam reference signals, and once a zone id is determined or used, the configured TCI states may be overridden by the beam reference signals determined by the zone id.

[0115] Before receiving a downlink signal, such as a PDCCH or PDSCH transmission, or a reference signal for a slot, the WTRU may first determine a zone, and then the WTRU may determine a beam for receiving the downlink signal. The WTRU may receive one or more downlink signals using the determined beam. In some embodiments, a WTRU or a group of WTRUs may report their current associated zone id. From the reported zone id, the gNB may be informed about the geographic location and movement direction of the group of WTRUs. One or more of the following scenarios may apply. In one scenario, the WTRU may be triggered to report the zone id if: the WTRU's associated zone id changes; the WTRU receives a report trigger message, e.g., via DCI or MAC-CE; the currently assigned or determined beam quality is below a threshold, where the beam quality may be based on at least one of RSRP, hypothetical BLER, or signal to interference plus noise ratio (SINR) of the beam reference signal; or the WTRU is at the boundary of two zones. In another scenario, one or more uplink resources may be reserved for zone id reporting. Dedicated PUCCH, PUSCH, or PRACH resources may be configured for zone id reporting. In one embodiment, a set of PUCCH resources may be configured, and one of the PUCCH resources may be determined as a function of a zone id, a WTRU id, or a cell id. Hereinafter, the term zone may be used interchangeably with zone, cluster, or region.

[0116] Zone-based PHY configurations may be used and / or configured by the WTRU. In some embodiments, the WTRU may be configured with one or more physical layer parameter configurations, such as a BWP, CORESET, search space, or PDCCH, PDSCH, PUSCH, or PUCCH configuration. One or more of the physical layer parameter configurations may be used based on the determined zone id. For example, one or more BWPs may be used, and an active BWP may be determined based on the zone id associated with the WTRU. The WTRU may start monitoring the PDCCH in a first BWP if the WTRU is associated with a first zone id, and the WTRU may start monitoring the PDCCH in a second BWP if the WTRU is associated with a second zone id.

[0117] Alternatively, a WTRU may be configured with one or more sets of CORESETs, and the WTRU may monitor the PDCCH using a first set of CORESETs if the WTRU is associated with a first zone id, and the WTRU may monitor the PDCCH using a second set of CORESETs if the WTRU is associated with a second zone id.

[0118] In one embodiment, a WTRU may be configured with two or more search spaces with the same or different CORESETs, and each search space may be assigned to a different zone. In an example embodiment, a WTRU may be configured with two search spaces, which may alternate between odd and even zone ids.

[0119] Beam management, in the context of HST, may be group-based. In some embodiments, one or more beam management operation modes (BMOM) may be used. A first beam management operation mode (BMOM) may be based on a WTRU-specific beam management mode, and a second BMOM may be based on a group-based beam management mode. For example, the first BMOM may determine the beams for the CORESET using RRC and MAC-CE signaling to indicate the beams, while the second BMOM may determine the beams for the CORESET based on one or more received or determined indicators. For example, such indicators may include an explicit indicator of a DCI or broadcast signal, where the DCI may be a group-common DCI monitored by a group of WTRUs, information about the geographic location of the WTRU, such as a zone id, or an implicit determination based on information about a time window, such as a set of slots, subframes, or radio frames.

[0120] The WTRU may determine the BMOM type, e.g., the first type or the second type, based on at least one of the following: higher layer configuration, absolute WTRU speed, or zone configuration for beam determination. In another embodiment, the WTRU may be configured or indicated to operate in a group-based beam management operation mode, such as group-based BMOM, and the group-based beam management operation mode may be based on the determined and / or indicated information. For example, the TCI state index of the CORESET may be indicated via a group DCI, which may be monitored in a common search space. The associated RNTI may be a group RNTI. The group RNTI may be determined based on a zone id selected by the WTRU in a slot. The group RNTI may be configured by the gNB. In another example, a CORESET may be configured for a group of WTRUs. For example, the CORESET configuration may be provided via a broadcast signal, such as a SIB.

[0121] The beam switching indicator for CORESET may be group-based. In some embodiments, WTRUs located in similar geographic locations and moving in the same or similar directions may be formed as a group. For example, a WTRU may receive an indicator for performing grouping, and the WTRU may perform a proximity check to find neighboring WTRUs. The proximity check may be based on the measurement quality of a proximity reference signal. For example, a WTRU may send a proximity reference signal, and WTRUs receiving the proximity reference signal and with a measurement quality above a threshold may be part of the same group. In some cases, a group id may also be indicated along with the proximity reference signal. In some cases, a WTRU may be instructed or configured to send a proximity reference signal along with the group id.

[0122] In some cases, the WTRU that determined the group id may implement a group-based beam management mode of operation and may stop implementing WTRU-specific beam management operations. The WTRU may inform the gNB of proximity reference signal reception and its associated quality, for example, by providing an RSRP level. Alternatively, the WTRU may inform the gNB of the determined group id. The gNB may confirm that the WTRU may use the group-based beam management mode of operation.

[0123] In one embodiment, group-based beam switching based on associated SSBs or CSI-RSs can be used. For example, a WTRU can be configured to monitor or measure SSBs for specific periods, and the WTRU can determine an associated SSB for each period. The determined SSB can be used as a beam for one or more configured CORESETs during the period. The PBCH of the determined SSB can include beam reference signal information, such as the TCI state of the CORESET during the period. Hereinafter, the terms SSB, SS / PBCH block, SS block, and beam measurement reference signal can be used interchangeably.

[0124] Embodiments directed to inter-cell HST and beam selection are described herein. One problem involved may be handing over a WTRU between cells, for example, in an inter-cell M-TRP scenario, when the WTRU moves at high speed in a train along a track. Performing handovers at high speed with low latency may pose challenges with measurements, configuration, and PDCCH monitoring from different cells with very different Doppler shifts. Another problem may be the volume of near-simultaneous handovers from WTRUs located in the same place in a train / car. Therefore, it is important to reduce the overhead of this type of signaling.

[0125] In some embodiments, the WTRU may support monitoring of multiple TCI conditions. In this way, the WTRU can address PDCCHs from different cells almost instantly. As the WTRU moves from one TRP cluster to the next, the following cell physical cell ID (PCI) may be configured for mobility measurements so that the next one relates to a different cell with a different PCI. In some cases, a gap with a high Doppler difference may be required for intra-frequency measurements. In some embodiments, when a gap is configured, the SMTC may be aligned with an SSB or CSI-RS burst, and therefore cell and beam detection latency may be optimal.

[0126] While the WTRU performs these measurements, in some embodiments, the gap may align with the particular PCI-SSB index of the detected beam so that the WTRU can measure and sweep through the beam index more quickly and have enough samples to make a sound decision to activate the particular TCI state and CORESET associated with the cell.

[0127] In some embodiments, the WTRU may be semi-statically configured with both PCI-related inter-cell TCI states belonging to both clusters, and may also be configured with a conditional handover that is performed based on measurement thresholds and will monitor a specific CORESET / PDCCH group of interest.

[0128] In some embodiments, if the SSB index can be spread evenly through the TRP cluster, the WTRU may initiate measuring the target PCI-related SSB based on the measurement threshold of the currently serving TRP and one or more of its detected SSB index or associated CSI-RS. A target detected PCI / SSB index detection across a certain threshold may automatically manifest as activation of an already configured TCI belonging to the target inter-cell TRP.

[0129] In some embodiments, due to high Doppler differences between opposite direction cells, the target handover cell may have its PDCCH-specific symbols time-multiplexed so that they do not overlap in the time domain, and thus the WTRU can simultaneously receive PDCCHs from both the serving cell and the target cell for a certain period of time while applying the correct Doppler for each PDCCH. In some cases, one or more symbols may be left between these two control channels to allow for the time required by the WTRU to apply automatic frequency control (AFC) Doppler correction and automatic gain control (AGC) adaptation.

[0130] If the networks are fully synchronized with respect to slot and frame boundaries, allowing common WTRU processing at the symbol / slot level, the overlapping PDCCH problem can be completely avoided in the time domain. In some embodiments, the WTRU can signal handover completion to the network upon correctly receiving / decoding the target cell PDCCH and subsequently the PDSCH transmission, or simply begin acknowledging the PDSCH transmission from the target cell. Upon receiving an ACK or CSI feedback for the target cell, the network can consider handover complete. Subsequent configurations for the next cell can be sent to the WTRU along with the next-subsequent target cell.

[0131] In some embodiments, the WTRU can receive multiple target cells in a single RRC message with a set of conditional handovers, meaning that a certain number of cells / SSBs can be configured in sequence. The WTRU can cycle through such configurations and perform all handovers conditionally. The WTRU can do this without any other single cell-based semi-static configuration, just the sequence of cells and the accompanying thresholds, SSB index, and PCI. In embodiments, conditional handover can dramatically reduce the amount of Layer 2 / 3 signaling. Similarly, the required WTRU measurement objects can be organized in a sequence, so that the WTRU can optimally perform only measurements related to the next target cell, reducing power consumption and cell / beam index detection time, both of which can be important in HST scenarios.

[0132] In some embodiments, an improved CSI framework can be applied in the context of HST. In NR, the CSI framework may operate based on three main configuration objects: CSI-ReportConfig, CSI-ResourceConfig, and a list of trigger states. An HST WTRU may be configured with one or more CSI configuration objects dependent on the HST zone or TRP. Furthermore, one or more detailed configurations of each object may depend on the zone or TRP.

[0133] In some embodiments, a WTRU may be configured with a CSI-ResourceConfig that contains multiple resource configurations, each of which may be linked to a zone or TRP. The WTRU may be configured to perform CSI measurements on the configured resources when the WTRU detects the corresponding zone or TRP beam.

[0134] In some embodiments, a WTRU may be configured with a CSI-ReportConfig that contains multiple reporting configurations, each of which may be linked to a zone or TRP. The WTRU may be configured to report CSI according to the configured reporting configuration when the WTRU detects the corresponding zone or TRP beam.

[0135] In some embodiments, a WTRU may be configured with a list of triggered states, where each state may be linked to a zone or TRP. The WTRU may be configured to use the configured trigger state when the WTRU detects the corresponding zone or TRP beam.

[0136] A CSI-RS configuration may use the same set of RSs for all segments. A CSI-RS configuration may have two or more CSI-RS sets so that each set can be used by the TRP based on a predefined or configurable pattern, such as an alternating pattern.

[0137] The linkage between the configuration object and the zone or TRP may be indicated in an implicit or explicit manner. In an implicit indication, the WTRU may determine that the CSI configuration corresponds to a zone or TRP according to a broadcast indication or a common control indication. In one such embodiment, the WTRU may be configured with a common CORSET dedicated to all HST WTRUs. For example, the HST CORESET may be used to receive all relevant information of all WTRUs in a zone. If the HST CORESET is not configured, the WTRU may use CORESET0 to obtain HST zone and TRP information. In some cases, the HST CORESET may indicate some additional relevant information, such as the identity of the current zone or TRP and the number of TRPs in the zone.

[0138] In some embodiments, the WTRU may be configured with a list that associates the configuration of the CSI configuration object as an index to a zone, which may be combined with the TCI information vector.

[0139] CSI-RS reporting can be performed in an efficient manner. In an HST scenario, many WTRUs may be grouped under the same movement conditions, and thus all of the WTRUs may experience and share very similar high Doppler or short coherency times for their corresponding radio channels. In an HST scenario with many WTRUs, reporting CSI at a high rate for each WTRU may not be feasible due to excessive feedback overhead and system resource usage.

[0140] It may be advantageous for CSI feedback to be limited to reporting components of Doppler information, such as Doppler spread and Doppler frequency, that will be valid for a duration of channel quiescence that is longer than the coherence time. Therefore, the rate of CSI reporting may be significantly reduced. However, in an HST scenario with hundreds of WTRUs per vehicle, CSI reporting even at a lower rate corresponding to channel quiescence may consume a significant percentage of resources. Because the Doppler information for all WTRUs in the HST may experience the same Doppler effect, it may not be necessary for all WTRUs to report their Doppler CSI; Doppler CSI reporting from only a selected number of WTRUs may be sufficient.

[0141] A WTRU may be configured to report its CSI information, e.g., Doppler information, on behalf of other WTRUs in the HST vehicle. The WTRU may report its CSI using one or more of the following mechanisms. For example, in some cases, the WTRU may be configured with a set of CSI-RS resources and may report its CSI report based on a random function. Because the number of WTRUs in the HST vehicle may vary, the WTRU may be configured with additional parameters to bias the random function according to the channel quiescence time and maintain a reasonable collision rate with reports from other WTRUs. In some cases, the WTRU may be configured to report its CSI information, e.g., Doppler information, only in specific zones preconfigured by a list. This configuration may also include per-zone CSI resource configuration. In other cases, a WTRU or group of WTRUs may be triggered to report their CSI information, e.g., Doppler information, only when indicated by a common DCI or MAC-CE. For group calls, WTRUs may use the same or different CSI resources for measurement purposes.

[0142] The CSI-RS configurations of multiple TRPs can be reused. CSI-RS resources can be used for beam management procedures in which CSI-RS are beamformed in different directions, or for codebook or non-codebook-based precoding. To avoid excessive RRC reconfiguration overhead when a WTRU moves rapidly from one TRP to another, a common CSI-RS configuration can be jointly configured for a group of TRPs. For example, TRPs can be located along a train track so that the same beam direction can be reused at each TRP. The beam direction can be pre-configured based on the geographical placement of the TRPs relative to the train's movement. The WTRU can assume that the same set of beam directions is available for all TRPs with the same CSI-RS configuration.

[0143] The same CSI-RS configuration may be reused for all TRPs, with a parameter as part of the CSI-RS configuration indicating the set of valid TRPs. The set of valid TRPs may be indicated according to one or a combination of factors. For example, the set of valid TRPs may be indicated by a list of TRP indices. When a WTRU moves and detects a TRP, the WTRU may determine whether the TRP index belongs to the set of valid TRPs for which the CSI-RS configuration is configured.

[0144] The set of valid TRPs may be indicated by a zone index representing a zone of the orbit. The zone index may be linked to a set of TRPs belonging to the same geographic area. The zone index may be included as part of the CSI-RS configuration, and the WTRU may determine the valid CSI-RS configuration based on its geographic location, e.g., determined via GPS signaling, and link it to the TRPs belonging to the geographic area.

[0145] The valid TRP set may be indicated by a validity period. The WTRU may detect TRPs using a CSI-RS configuration and an associated timer, and the WTRU may determine after detecting a TRP that it can apply the same CSI-RS configuration to all subsequent TRPs detected within the validity period, which may be the duration of a trip. After expiration of the timer, a different CSI-RS configuration may be linked to be applied to the next set of TRPs. The WTRU may be configured with multiple CSI-RS configurations, which may each be linked with its own timer, so that the WTRU can determine one configuration that is valid after expiration of another configuration's timer.

[0146] A CSI-RS configuration may be associated with two or more CSI-RS sets, and each set may be active according to a pattern. The WTRU may limit its monitoring to only the set of CSI-RSs that are active, and each TRP may not need to be signaled to the WTRU for which set is active if the WTRU is pre-configured with a pattern. The pattern may consist of or be configured as a sequence of TRPs for which each set is active, a sequence of geographical areas indicating which sets are active in which areas, or a timer associated with each set that determines the period during which the set is active.

[0147] FIG. 5 illustrates a WTRU moving 502 along a trajectory 504. In the illustrated example, odd-numbered TRPs, including TRP1 506 and TRP3 508, may be located in the north of the trajectory 504. TRP1 506 and TRP3 508 may have beams pointing south. Even-numbered TRPs, including TRP2 510, may be located in the south of the trajectory with beams pointing north. A pattern may be configured at the WTRU 512 to indicate that one set of CSI-RS may be active for the odd-numbered TRPs, while the other set of CSI-RS may be active for the even-numbered TRPs. The WTRU may adjust its receive / transmit beams according to the TRP index detected as the WTRU moves. For example, the WTRU may face a side with odd-numbered TRPs, and the WTRU may decide to activate only the WTRU's panels facing the odd-numbered TRPs. Alternatively, or in combination, TRP1 506 and TRP3 508 may be configured in the same geographic area, and TRP2 510 may be configured in a different area. When a WTRU enters the geographic area of TRP2 510, the WTRU may decide to change its spatial transmit / receive filters to match the CSI-RS configuration active in the geographic area of TRP2 510.

[0148] The CSI-RS resources may be triggered on a TRP different from where the trigger signal is sent. When a WTRU moves at high speed, one TRP may send a control signal that triggers the aperiodic CSI-RS, and the WTRU may not have enough time to send the CSI-RS before the WTRU moves. Furthermore, the WTRU may need some time after receiving the trigger message to adjust its transmission configuration, for example, by activating or deactivating a panel or changing a beam. While the aperiodic CSI-RS resources may be triggered by a control signal on one TRP, the aperiodic CSI-RS resources may be sent on another TRP. The trigger control signal may include a TRP index indicating the TRP that can send the AP-CSI-RS, an offset index n indicating the TRP with n indexes offset from the triggering TRP that can send the CSI-RS, or the TCI state of the TRP sending the AP-CSI-RS. The TCI state may be different from the TCI state of the trigger message. The WTRU may determine from the trigger message, and may adjust its transmit / receive filters according to the TCI of the TRP sending the AP-CSI-RS.

[0149] The WTRU may assume that the triggering TRP and the TRP sending the CSI-RS use the same CSI-RS configuration, e.g., the same number of ports, CSI-RS, etc. Aperiodic triggering may be done by DCI or MAC CE. For example, in FIG. 5, TRP1 506 may send a DCI to the WTRU triggering aperiodic CSI-RS transmission, and the DCI may include an index of TRP3 508. The CSI-RS may be triggered to be sent on TRP3 508. The WTRU may activate its panel to determine to receive set 1 of CSI-RS when approaching TRP3 508. The WTRU may also be configured with a set of TRPs on which TRPs may send aperiodic CSI-RS. The trigger message may include a list of TRPs that may be activated. As the WTRU moves through various TRPs, it may determine that it can receive multiple aperiodic CSI-RS without requiring an individual trigger message from each TRP.

[0150] The WTRU may be triggered to send a CSI report on a TRP different from the TRP from which the CSI-RS resource was sent. The WTRU may determine the TRP to send the CSI report on based on an index included in the trigger message, such as a TRP index, or an offset index indicating the offset between the TRP sending the trigger and the TRP receiving the report. The WTRU may also be configured with a set of TRPs to which the WTRU can send a report. If the WTRU determines that it should be served by a TRP that is not in the valid set, the WTRU may omit sending the CSI report. Similarly, the WTRU may be triggered to send SRS resources on a TRP different from the TRP sending the trigger signal. The TRP index may be included with the trigger signal. The WTRU can determine which panel and which SRS resource to send at what time based on the TRP index included in the trigger signal.

[0151] In embodiments, efficient reference signal transmission can be used. In NR, a WTRU may be configured to receive tracking reference signals to assist the WTRU in tracking the frequency and timing of a gNB. If necessary, a WTRU in RRC connected mode may receive a higher layer WTRU-specific configuration of the NZP-CSI-RS Resource Set configured in the higher layer parameter trs-Info. Depending on the WTRU's location relative to the transmission point, the WTRU may experience different levels of Doppler shift. A high-speed WTRU may experience the fastest rate of change in Doppler shift when the WTRU is relatively close to the transmission point. Because a higher Doppler shift may require a higher rate of TRS transmission, the WTRU may be configured to receive and process the TRS at variable transmission rates.

[0152] In some embodiments, the TRS pattern may be location-based. In one embodiment, for example, a multi-TRP transmission deployment in a high-speed train scenario may be divided into multiple zones. The WTRU may receive a configuration to expect TRS transmissions with different periodicities in each zone. In an exemplary embodiment, the zones between every third TRP may be divided into two or more zones, e.g., two, three, or more zones, where a first zone and a third zone may represent an area near the first TRP and a second TRP, and the second TRP may represent an area relatively far from either TRP. In this case, the WTRU may be configured to receive a TRS with one set of transmission properties, e.g., higher periodicity in the first zone and the third zone, and another set of transmission properties, e.g., lower periodicity in the second zone. In one embodiment, the WTRU may indicate the presence of a WTRU in a zone based on using different SRS transmission resources.

[0153] The WTRU may always be configured to operate at either the lower or higher TRS transmission periodicity and then be instructed to operate in the other mode as needed.

[0154] In some embodiments, the TRS pattern may be dynamically indicated. A WTRU may be configured with two or more TRS configurations, each configuration having a TRS density preconfigured in time. The WTRU may, for example, dynamically indicate a DCI or MAC CE to alternate between the two configurations. For example, the WTRU may receive a single bit in the DCI to indicate a preferred TRS pattern. In some cases, the WTRU may be implicitly indicated to use a TRS configuration other than the one used for the scheduled transmission. For example, the WTRU may use one configuration for a lower MCS while using another configuration for a higher MCS.

[0155] In some embodiments, a WTRU may be configured with two or more TRS configurations, each of which may have a similar TRS density in time, but each of which may have a different time offset. If desired, the WTRU may be indicated to expect one or more TRS transmissions.

[0156] In some embodiments, a non-uniform TRS pattern may be used. The WTRU may be configured with a TRS configuration in which the resource allocation is not spread evenly over time. In one embodiment, the WTRU may be configured with a TRS resource allocation pattern that may be defined over several slots, which may be referred to as a TRS frame. The number of slots per TRS frame may be configured according to the WTRU speed. In a TRS frame, the TRS density over time is not uniform, with certain slots being higher than others. TRS transmissions with a non-uniform pattern may be activated / triggered aperiodically. The WTRU may expect to start receiving TRS at a higher density based on measurements or criteria. For example, the TRS frame may be restarted each time the measurements or criteria are met.

[0157] In some embodiments, the WTRU may be configured with a TRS pattern that has a higher density in the middle of the pattern. In some embodiments, the WTRU may expect a reset or restart of the TRS frame when a measurement on the serving TRP, e.g., RSRP, reaches a threshold. Alternatively or additionally, the WTRU may expect a reset or restart of the TRS frame after a measurement on the serving TRP falls within a preconfigured range for a second TRP, e.g., when RSRP1 falls within x dB of RSRP2, where x is a configurable value. In some embodiments, the WTRU may reset or restart the TRS frame based on the WTRU's geographic location.

[0158] In some embodiments, a TRS triggering mechanism may be used. For example, triggering TRS transmissions or TRS transmissions with higher density may be based on a WTRU or gNB decision. In a WTRU-based embodiment, the WTRU may request the initiation of TRS transmissions or request TRS transmissions with higher density based on some criteria. For example, the WTRU may perform downlink measurements, e.g., RSRP, CQI, Doppler, etc. Alternatively or additionally, the WTRU may make such a request based on the WTRU's determined location.

[0159] In a gNB-driven embodiment, the gNB may use different TRS configurations based on uplink measurements. In one embodiment, the WTRU may be configured with multiple SRS configurations, each of which may be associated with a TRS configuration. Association may be implemented via RRC, MAC CE, DCI, or a combination thereof. The WTRU may be configured to perform SRS transmissions using a default SRI, which may be associated with a default TRS configuration. Based on the WTRU's SRS transmission, the gNB may determine a required TRS configuration and may indicate a preferred TRS mode via the SRI. The WTRU may determine a new TRS configuration via the received SRI.

[0160] In some embodiments, such as a high-speed train scenario where there are many WTRUs experiencing the same Doppler, once the TRP successfully receives one request from a WTRU, the TRP may change the TRS periodicity for all WTRUs. Thus, the WTRUs may not expect to receive a dedicated response to their own request. For this purpose, or other similar situations involving all WTRUs in a train, the WTRUs may expect the DCI to be received within a common search space, where the DCI may be scrambled with a unique RNTI intended for all WTRUs in the train. Alternatively or additionally, once the WTRU decides to change its TRS configuration, it may not expect any response.

[0161] In some embodiments, a WTRU may receive a specific identification and configuration to be a designated WTRU and represent other WTRUs in a train. A WTRU may receive configuration to become a designated WTRU semi-statically or dynamically. A WTRU may be configured to act as a designated WTRU only in certain slots, radio frames, etc. A designated WTRU may be assigned a specific RNTI and other dedicated configurations, e.g., SRS, PUCCH, PUSCH, and SR configurations. The eNB may indicate a designated WTRU based on whether the designating WTRU is transmitting data above priority, whether the WTRU has high battery power, etc.

[0162] In some embodiments, assuming the presence of sidelink operation as well as operation in V2V communications, a designated WTRU may help the network update the positioning information of other WTRUs in its vicinity.

[0163] In some embodiments, the WTRU may support aperiodic TRS and / or semi-persistent TRS, which may be associated with periodic TRS. Hereinafter, the term aperiodic TRS may be used interchangeably with the terms semi-persistent TRS and multi-shot TRS. Hereinafter, the term TRS resource set may be used interchangeably with the terms TRS resource, CSI-RS resource set, CSI-RS resource, CSI-RS resource set with trs-Info, CSI-RS resource for tracking, and / or CSI-RS for tracking. In some embodiments, the association between aperiodic TRS and periodic TRS may be based on one or more of RRC signaling, one or more MAC CEs, one or more DCIs, and / or any logical equivalents of the foregoing signaling.

[0164] In some embodiments, a WTRU may be configured with aperiodic TRSs, periodic TRSs, and an association between the aperiodic TRSs and periodic TRSs via RRC signaling. The association may be based on a TRS resource set ID and / or QCL type. For example, a periodic TRS resource set configuration may include an associated aperiodic TRS resource set ID. One or more QCL types of aperiodic TRSs, e.g., one or more of QCL type A, QCL type B, QCL type C, QCL type D, etc., may include an associated periodic TRS resource set ID.

[0165] In some embodiments, the WTRU may be configured with aperiodic TRS and periodic TRS (e.g., via RRC). Based on the configuration, the WTRU may receive (e.g., via MAC CE) an association between the aperiodic TRS and the periodic TRS. The association may be based on one or more of the following: a TRS resource set ID, a TCI state ID, or an SSB ID. For example, the WTRU may receive via MAC CE a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated TRS resource set ID (e.g., a periodic TRS resource set ID). Based on the indication, the WTRU may determine an association between the periodic TRS resource set and the associated aperiodic TRS resource set. In some cases, the WTRU may receive via MAC CE a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated TCI state ID. Based on the indicated TCI state, the WTRU may determine the associated TRS resource set (e.g., the periodic TRS resource set associated with the indicated TCI state). In some cases, the WTRU may receive a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated SSB ID via the MAC CE. Based on the indicated SSB ID, the WTRU may determine the associated TRS resource set (e.g., a periodic TRS resource set associated with the indicated SSB).

[0166] In some embodiments, a WTRU may be configured with aperiodic TRS and periodic TRS (e.g., via RRC). Based on the configuration, the WTRU may receive (e.g., via DCI) an association between the aperiodic TRS and the periodic TRS. The association may be based on one or more of the following: an aperiodic TRS trigger, a TRS resource set ID, a TCI state ID, or an SSB ID. In some embodiments, for example, an aperiodic TRS trigger configuration may include (e.g., via RRC) one or more pairs of a triggered aperiodic TRS resource set and an associated periodic TRS resource set. When the WTRU receives an aperiodic TRS trigger in an aperiodic TRS trigger configuration, the WTRU may receive the aperiodic TRS resource set associated with the associated periodic TRS resource set. In some embodiments, for example, the WTRU may receive a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated TRS resource set ID (e.g., a periodic TRS resource set ID) via DCI. Based on the indication, the WTRU may determine an association between the periodic TRS resource set and the associated aperiodic TRS resource set. In some embodiments, for example, the WTRU may receive a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated TCI state ID via the DCI. Based on the indicated TCI state, the WTRU may determine an associated TRS resource set (e.g., a periodic TRS resource set associated with the indicated TCI state). In some embodiments, for example, the WTRU may receive a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated SSB ID via the DCI. Based on the indicated SSB ID, the WTRU may determine an associated TRS resource set (e.g., a periodic TRS resource set associated with the indicated SSB). The DCI may be based on one or more of the following:WTRU-specific DCI, uplink DCI, downlink DCI, sidelink DCI, and / or group DCI.

[0167] It should be understood that the signaling of aperiodic TRS and / or periodic TRS, and the association between aperiodic TRS and periodic TRS, may be provided by RRC signaling, MAC-CE, or the logical equivalent of DCI.

[0168] In some embodiments, the WTRU may request an aperiodic TRS resource set and / or one or more preferred parameters for aperiodic TRS transmissions from the gNB. The request (e.g., via one or more of the PUCCH, PUSCH, and MAC CE) may be based on one or more of an explicit value indicator or a value indicator based on configured / predefined candidates.

[0169] The WTRU and gNB may determine the application of the reported parameters based on one or more factors. Such factors may include a processing time X, which may be provided from the WTRU via a request. For example, the WTRU may apply one or more parameters for aperiodic TRS transmissions after processing time X. Another factor may be the period for receiving a gNB confirmation. For example, the WTRU may receive a confirmation from the gNB about the WTRU report. Based on the confirmation, the WTRU may apply one or more parameters for aperiodic TRS transmissions. In some embodiments, the confirmation may be a PDCCH transmission within a CORESET, and / or the CORESET may be a dedicated CORESET for aperiodic TRS parameter change confirmation.

[0170] Parameters for aperiodic TRS may include one or more of the following: periodicity, offset, consecutive slots, CSI-RS density, frequency band, power control offset, or number of transmissions (e.g., number of TRS transmissions with consecutive slots).

[0171] In one embodiment, the WTRU may receive a trigger for aperiodic TRS activation or deactivation based on the DCI and / or MAC CE. The DCI may include an aperiodic TRS trigger field. For example, the WTRU may receive the trigger based on the aperiodic TRS trigger field. The DCI may include a TRS resource set ID. For example, the WTRU may receive the TRS resource set ID via the DCI. Based on the indication, the WTRU may trigger, activate, or deactivate the aperiodic TRS resource set. The DCI may include a TCI state ID. For example, the WTRU may receive the TCI state ID via the DCI. Based on the indicated TCI state, the WTRU may determine an associated TRS resource set (e.g., the aperiodic TRS resource set associated with the indicated TCI state). The DCI may also include an SSB ID. For example, the WTRU may receive the SSB ID via the DCI. Based on the indicated SSB ID, the WTRU may determine an associated TRS resource set (e.g., an aperiodic TRS resource set associated with the indicated SSB). The DCI may include an activation / deactivation field. For example, the WTRU may receive an activation and / or deactivation indication via the DCI. Based on the indication, the WTRU may activate and / or deactivate one or more indicated TRS resource sets. The DCI may be one or more of the following: a WTRU-specific DCI, a downlink DCI, an uplink DCI, a sidelink DCI, and / or a group DCI. The PDCCH containing the DCI field may be scrambled with a specific RNTI for aperiodic TRS triggering.

[0172] The MAC CE that triggers activation or deactivation of the aperiodic TRS may include one or more of several identifiers. For example, the WTRU may receive a TRS resource set ID via the MAC CE. Based on the indication, the WTRU may trigger, activate, or deactivate the aperiodic TRS resource set. In some embodiments, the WTRU may receive a TCI state ID via the MAC CE. Based on the indicated TCI state, the WTRU may determine an associated TRS resource set (e.g., an aperiodic TRS resource set associated with the indicated TCI state). In some embodiments, the WTRU may receive an SSB ID via the MAC CE. Based on the indicated SSB ID, the WTRU may determine an associated TRS resource set (e.g., an aperiodic TRS resource set associated with the indicated SSB). In some embodiments, the WTRU may receive an activation and / or deactivation indication via the MAC CE. Based on the indication, the WTRU may activate and / or deactivate the indicated one or more TRS resource sets. In some embodiments, the MAC CE message may be identified based on a particular logical channel ID. In some embodiments, the WTRU may request an aperiodic TRS transmission based on one or more of a TRS resource set index and / or a WTRU measurement of Doppler shift. The TRS resource set index may be based on one or more identifiers. For example, the WTRU may receive a TRS resource set ID via the MAC CE. Based on the index, the WTRU may trigger / activate / deactivate an aperiodic TRS resource set. In some embodiments, the WTRU may receive a TCI state ID via the MAC CE. Based on the indicated TCI state, the WTRU may determine an associated TRS resource set (e.g., an aperiodic TRS resource set associated with the indicated TCI state). In some embodiments, the WTRU may receive an SSB ID via the MAC CE.Based on the indicated SSB ID, the WTRU may determine an associated TRS resource set (eg, a non-periodic TRS resource set associated with the indicated SSB).

[0173] It should be appreciated that the signaling TRS resource set, TRS resource set index, TRS configuration, and / or configuration information may be provided via RRC signaling, MAC-CE, or the logical equivalent of a DCI.

[0174] In embodiments in which the WTRU requests aperiodic TRS transmission based on Doppler measurements, the WTRU may report one or more values of parameters (e.g., Doppler shift, Doppler spread, average delay, delay spread, etc.) to the gNB. Based on the report, the WTRU may receive the aperiodic TRS resource set. For example, if the reported one or more values are greater than a threshold, the WTRU may receive the aperiodic TRS resource set (the gNB may transmit the aperiodic TRS resource set). In some cases, if the reported one or more values are less than (or equal to) a threshold, the WTRU may not receive the aperiodic TRS resource set (the gNB may not transmit the aperiodic TRS resource set). The WTRU may indicate a resource set index (e.g., a TRS resource set ID) for the measurement to the gNB.

[0175] In some embodiments, the WTRU and gNB may determine the requested aperiodic TRS transmission based on a time offset X from the WTRU request and / or based on receiving a confirmation from the gNB. For example, in some cases, the WTRU may receive an aperiodic TRS transmission after a time X (e.g., ms, slots, symbols, etc.) from the request. In some cases, the WTRU may receive a gNB confirmation for the WTRU request. Based on the confirmation, the WTRU may receive the aperiodic TRS transmission. The confirmation may be, for example, a PDCCH transmission within a CORESET. The CORESET may be a dedicated CORESET for the aperiodic TRS request from the WTRU.

[0176] The TRS and SRS may be estimated, measured, determined, and / or reported aperiodically. In some embodiments, the WTRU may estimate, measure, and / or determine Doppler frequency-related information and report the Doppler frequency-related information when one or more predefined conditions are met. Hereinafter, Doppler frequency may be used interchangeably with frequency offset. One or more of the following situations may apply. For example, the Doppler frequency-related information may include a Doppler frequency value (e.g., a frequency offset value), a Doppler frequency rate of change (Δ DF ), or the sign (e.g., positive or negative) of the Doppler frequency. The Doppler frequency rate of change may be determined based on one or more of the following parameters: For example, the Doppler frequency rate may be Δ DF =(Δ F1 -Δ F2 ) / Δ T where Δ F1 may be the first Doppler frequency at T1, and Δ F2 may be the second Doppler frequency at T2, and Δ T is the time gap between T1 and T2 (e.g., Δ T =T2-T1).

[0177] The predefined condition may be at least one of the following: the Doppler frequency rate of change is higher than a threshold, the Doppler frequency sign is changing, or the Doppler frequency value is higher than a threshold.

[0178] A WTRU may be indicated, configured, or determined to periodically estimate the Doppler frequency rate, and the periodicity of the Doppler frequency rate estimation may be determined based on one or more of the configuration, the location of the WTRU, or the velocity of the WTRU. For example, a WTRU at a first geographic location (e.g., a first zone) may estimate the Doppler frequency rate with a first periodicity, and a WTRU at a second geographic location (e.g., a second zone) may estimate the Doppler frequency rate with a second periodicity. The periodicity may be shorter for a WTRU at a geographic location closer to the boundary of two TRPs. In another example, a WTRU at a first velocity may estimate the Doppler frequency rate with a first periodicity, and a WTRU at a second velocity may estimate the Doppler frequency rate with a second periodicity.

[0179] A set of uplink resources may be configured to report Doppler frequency-related information when one or more predefined conditions are met. The set of uplink resources may be periodic PUCCH resources. The WTRU may send the Doppler frequency change-related information in the configured uplink resources when one or more of the predefined conditions are met. Alternatively, the configured uplink resources may not be used.

[0180] The Doppler frequency related information may be at least one of the following: aperiodic TRS and / or SRS request for frequency offset pre-compensation, a high Doppler frequency change indicator, Doppler frequency change rate related information (e.g., Δ DF ), proximity to the boundary between two TRPs, or proximity to a specific zone (or TRP).

[0181] In some embodiments, one or more SRS resources may be configured, and the WTRU may transmit an SRS in the one or more configured SRS resources when at least one of the following conditions is met: the Doppler frequency change rate is higher than a threshold, the sign of the Doppler frequency has changed, or the Doppler frequency value is higher than a threshold.

[0182] In some embodiments, there may be an association between TRS and SRS operations. In some embodiments, the WTRU may support a TRP-based frequency offset pre-compensation scheme.

[0183] FIG. 6 illustrates an example of a TRP-based frequency offset pre-compensation method 600. Shown in FIG. 6 are a WTRU 602 and two TRPs, including a first TRP 604 and a second TRP 606. The WTRU 602 may receive and measure a first TRS resource set 608 from the first TRP 604 and a second TRS resource set 610 from the second TRP 606. Based on the reception and measurement, the WTRU 610 may determine a TRP for transmission and report the determination based on transmitting an uplink signal (e.g., SRS, PRACH, etc.) and / or an uplink channel (e.g., PUCCH) in one or more dedicated uplink resources. For example, if the first TRP 604 is determined based on the first TRS resource set 608, the WTRU may transmit an uplink signal and / or an uplink channel 612 in the first uplink resource associated with the first TRS reference set 608. If the second TRP 606 is determined based on the second TRS resource set 610, the WTRU may transmit an uplink signal and / or an uplink channel 614 in a second uplink resource associated with the second TRP 606. Based on the transmission, the WTRU and the gNB may determine a frequency offset for pre-compensation and transmit / receive a PDCCH and / or a PDSCH 616-618 to / from the TRP determined from the first TRP 604 or the second TRP 606.

[0184] The TRP determination may be based, for example, on WTRU measurements. For example, the WTRU may measure one or more values of a parameter based on a TRS resource set. Based on the measurements, the WTRU may determine a TRS resource set for TRP determination. One or more of the following rules may apply: In some embodiments, if one or more measured values of a TRS resource set are greater than a threshold, the WTRU may determine a TRS resource set. If one or more measured values are less than (or equal to) a threshold, the WTRU may not determine a TRS resource set. In some embodiments, the WTRU may compare one or more measured values from multiple TRS resource sets. Based on the measurements, the WTRU may determine a TRS resource set that provides the largest (or smallest) value of the multiple TRS resource sets.

[0185] The parameters measured by the WTRU may be one or more Doppler-related parameters (e.g., Doppler shift, Doppler spread, average delay, or delay spread), SINR, distance and / or path loss, zone, or BRS. With respect to distance, for example, a TRS resource set having a shorter distance or lower path loss from the WTRU may be determined. With respect to zone, for example, a TRS resource set associated with the zone in which the WTRU is located may be determined. With respect to BRS, for example, a TRS resource set may be determined based on measurements of associated BRS resources / resource sets. The BRS may be one or more of CSI-RS and SSB for CSI-RS resources / resource sets, or beam management resources / resource sets.

[0186] The association between the TRS resource set and the uplink signal and / or uplink channel may be based on one or more of a gNB configuration, an indicator, or a predefined relationship. In some embodiments, the WTRU may receive the configuration and / or indicator for the association. The association may be configured or indicated based on one or more of the following: a TRS resource set ID, an SRS resource / resource set ID, a CORESET / SS group, a higher layer (e.g., MAC, RLC, PDCP, or SDAP layer) index, a TRP ID, a PUCCH resource ID, a PRACH resource ID, or an associated TCI state ID or TCI state group ID. The configuration / indication may be sent or received using one or more of the following: an RRC message, a MAC CE, a DCI (WTRU-specific DCI and / or group DCI), or a system information block (SIB).

[0187] In embodiments where the association is based on a predefined relationship, one or more of the following parameters may be used to determine the association: a cell ID associated with the TRS resource set, a TRS resource set ID associated with the TRS resource set, an SSB ID associated with the TRS resource set, a TRP ID associated with the TRS resource set, or a configured parameter of the TRS resource set (e.g., periodicity, density, burst, time offset, or frequency offset).

[0188] FIG. 7 illustrates an example of an M-TRP SFN transmission 700 with Doppler compensation. In this example, for cell n 702, four TRPs 706-712 are located along a track 714 on which a train 716 can run. In an M-TRP SFN deployment in which M TRPs jointly transmit to a WTRU, the WTRU may experience a different Doppler shift from each TRP. These Doppler shifts are shown as Δf1 704a from TRP2 708 and Δf1 704b from TRP3 710. If Doppler compensation is performed by the TRPs, for proper operation of the M-TRP SFN, at least M-1 TRPs may perform Doppler shift pre-compensation so that the received carrier frequency matches at the WTRU. An indication of whether a TRP can or cannot perform Doppler pre-compensation may be dynamically provided.

[0189] In some embodiments, the TRP for performing Doppler pre-compensation may be selected based on the geographic location or region of the WTRU. To this end, the network may configure the WTRU with a particular SRS resource set to be used based on the WTRU's geographic location or the region to which the WTRU belongs. The WTRU's selection of an SRS may indicate the WTRU's geographic location / region to the network.

[0190] In some embodiments, the TRP for performing Doppler pre-compensation may be selected based on channel state information (CSI) measurements at the WTRU. For this purpose, the reference-signal received power (RSRP), channel quality indicator (CQI), or reference signal received quality (RSRQ) from each TRP may be used. For example, the RSRP or RSRQ from each TRP may be tested or compared against a particular threshold. The selection of the TRP for performing Doppler pre-compensation may be made by the network based on reported RSRP, CQI, or RSRQ measurements sent from the WTRU to the network. In some embodiments, the selection of the TRP may be made at the WTRU and indicated to the network by transmitting an SRS selected from a pre-configured SRS set. The WTRU's selection of an SRS / SRS resource set may indicate the TRP for performing Doppler pre-compensation.

[0191] In some embodiments, the network can use downlink signaling to request aperiodic or semi-persistent SRS transmissions from the WTRU to indicate which TRPs should perform Doppler pre-compensation. For example, if more than one TRP implements SFN, the TRP to perform or not perform Doppler pre-compensation can be indicated by the WTRU transmitting an SRS from a pre-configured SRS set to a particular TRP. In this manner, a WTRU can be configured with two different sets of SRS resources, with an association between each SRS resource and a TRP. For example, a WTRU can be configured with a first set and a second set of SRS resources associated with a first TRP and a second TRP. If the WTRU uses the first SRS resource, the WTRU indicates a preference for pre-compensation with the first TRP. If the WTRU uses the second SRS resource, the WTRU indicates a preference for pre-compensation with the second TRP.

[0192] In some embodiments, upon receiving an aperiodic trigger for SRS, the WTRU may determine one of a set of possible SRS resources. Each SRS resource from this set may have different characteristics, such as different subcarrier spacing. The WTRU may determine the SRS resource in the set based on measurement results obtained from at least one measurement resource. For example, the measurement results may consist of or comprise an estimate of the time variation (or Doppler spread) of the channel from a reference signal such as TRS or PT-RS. Alternatively or additionally, the WTRU may determine the SRS resource based on an estimate of the WTRU velocity from positioning information. For example, the WTRU may select a first SRS resource if the Doppler estimate (or WTRU velocity) is below a threshold, and may select a second SRS resource if the Doppler estimate (or WTRU velocity) is above the threshold. The threshold and measurement resources may be configured by higher layers for the set of possible SRS resources. The WTRU may report the estimated Doppler, the WTRU velocity, or the selected SRS resource, for example, in a measurement report. Such an embodiment may help the network to receive resources adapted to estimate the required Doppler pre-compensation.

[0193] The SSB configuration may be used for bidirectional transmission. The SSB may generally be considered as the basis on which the WTRU performs cell / beam detection and measurements. Therefore, the periodicity of the SSB may be linked to the reading of the cell's MIB. There may be other RS signals that may be configured per WTRU or for a set of WTRUs, for example for mobility purposes such as CSI-RS. These RS may not necessarily be linked to cell detection.

[0194] Generally, SSB can also be used for AFC and AGC. In the context of HST use cases, the WTRU's assumptions regarding these RSs can be important as they directly impact demodulation and mobility.

[0195] In some cases, a WTRU may always have an anchor TRP, so that Doppler effects can be effectively assessed and compensated for. The WTRU may, for example, be indicated via a particular SRS that the TRP is the anchor. Thus, other serving TRPs can precompensate or adjust the PDSCH and associated DM-RS. Some RS signals may need to be precompensated, while other RS signals may not need to be precompensated from non-anchor TRPs.

[0196] Some embodiments may not implement pre-compensation of SSBs. In some embodiments, a non-anchor TRP may not perform Doppler compensation on any of its SSBs because these SSBs may serve global mobility for all trains in any direction. Under these embodiments, the non-anchor TRP may perform pre-compensation in conjunction with the PDSCH using one or more CSI-RS. The non-anchor TRP may be configured per WTRU or group of WTRUs to have CSI-RS-related measurements and may provide feedback based on the compensated channel. Furthermore, local train-car beam mobility under the same non-anchor TRP may be managed under the pre-compensated CSI-RS signal. For local beam-based mobility, the gNB may configure a specific beam with CSI-RS restricted to a specific WTRU or group of WTRUs. The CSI-RS may be configured via an RRC message or any other logically equivalent message in a measurement object associated with the serving or neighboring cell. Additionally or alternatively, the WTRU can derive the allowed beams and their linked CSI-RS or RS via the configured TCI state. The TCI state, when activated, may contain an indication of which beams can be measured under the assumption of the same CSI-RS (e.g., QCL). In this way, the WTRU can distinguish between local mobility beams and non-precompensated beams, and therefore, local mobility is not allowed. Under this embodiment, the WTRU may use SSBs for global mobility and Doppler estimation, while precompensated CSI-RS is used for local mobility and channel feedback. Thus, the WTRU may configure a set of SRSs associated with precompensated CSI-RS and separately configure a set of SRSs associated with SSBs.These SRS sets can be separately triggered periodically or aperiodically on different dedicated timelines via specific DCI commands, where a specific SSB index or CSI-RS index or SRS resource type that can be associated with a range or index is indicated. In this way, the gNB can correctly measure and act on the pre-compensation adjustments.

[0197] Some embodiments may implement pre-compensation of SSBs. Some embodiments may involve static grouping of SSBs using SIBs. A non-anchor TRP may compensate for a specific number of beams and their associated SSBs based on specific conditions. For example, a cell may indicate in one or more SIBs a specific number of ranges of SSB indices that may belong to different TRPs under the same cell ID. Thus, each TRP belonging to a cell may have a defined range or ranges of reserved SSBs. Under this type of configuration, different ranges under different TRPs of a cell may be linked. For example, if a WTRU selects range 1 for TRP1 based on its SSB measurements, the WTRU may prioritize SSBs under range 2 for TRP2. SSB range linking may also indicate the QCL assumptions for SSBs under each TRP and whether the SSBs are compensated. Under this SSB linking method, the WTRU may use the SSB ranges of local train vehicle mobility for measurement priority. Furthermore, for example, if the TCI configuration state indicates an SSB index from a particular range, the WTRU may consider all SSB indices belonging to the signaled range that have the same QCL assumption.

[0198] The SRS resources may be divided per SSB range and configured by the gNB accordingly, so that the gNB knows exactly which TRPs the WTRU uses as anchor TRP references and which TRPs are non-anchor TRPs.

[0199] Some embodiments may involve semi-static grouping based on SSB index ranges. SSB range grouping may serve different directions to users on different trains. Pre-compensation of a specific range of SSB (beam) may begin after WTRU connection and may consequently be configured by RRC signaling or another logically equivalent signal. Thus, a dynamic manner in which SSB ranges are formed and reserved for specific directions of a WTRU or group of WTRUs may be envisioned. As a result, the signaled state of the TCI will follow the new SSB index grouping or reservation. The WTRU may assume that an SSB index has the same QCL properties as all beams belonging to the same configured range.

[0200] Under these embodiments, dynamic reservations may enable load balancing and WTRU measurement optimization. Similarly, the TCI state, which contains information about the SSBs of a beam, may indicate the same assumptions for the entire defined range of SSB indices.

[0201] Some embodiments may involve signaling opposite beam directions for the SSB. A secondary index / division of the SSB index range formed in any of the above cases (SIB, RRC semi-statically or dynamically configured) may be done by indicating opposite beam directions via a direction bit. This signaled direction bit may serve a subgrouping of WTRU beam ranges under certain similar QCL assumptions where the different direction bits are QCL discriminators. This beam direction discriminator may be extended to a subgrouping of SRS indices that the WTRU can correctly use to serve TRPs under a particular beam range and / or direction.

[0202] A reduced step acquisition mode may be entered by the WTRU. Because an HST WTRU may be camped on the same cell for an extended period of time, the cell ID may not change and continuous performance of all steps related to PSS / SSS and PBCH detection may not be required. Therefore, the WTRU may enter a reduced step acquisition (RSA) mode in which at least some of the functionality related to SSB detection and decoding may be omitted.

[0203] In some embodiments, the WTRU may operate in RSA mode based on one or more of the following conditions: For example, the WTRU may be configured by RRC configuration or another logically equivalent signal to operate in RSA mode; The WTRU may enter RSA mode based on an implicit or explicit indication in an IE received in an L1 / L2 command; The WTRU may enter RSA mode based on a determination of downlink resource usage, e.g., an implicit indication via a specific CSI-RS configuration or detection of TRS usage; The WTRU may enter RSA mode based on measurements, e.g., Doppler shift, Doppler spread, RSRP, SINR, positioning, etc.; The WTRU may enter RSA mode based on a determination that pre-compensation has not been applied to the SSB.

[0204] Once in RSA mode, the WTRU may perform one or more of the following procedures until it exits RSA mode. The WTRU may store and continue to use the last determined cell identity, MIB, SIB1 PDCCH bandwidth, common CORESET, common SS, etc., decoded before entering RSA mode. The WTRU may start performing measurements on a specific CSI-RS configuration, e.g., RSA-CSI-RS, that may be configured for RSA mode. The WTRU may receive RSA-CSI transmissions periodically, or the WTRU may expect to receive RSA-CSI transmissions within a preconfigured window upon triggering by the WTRU. The WTRU may continue to perform timing / frequency measurements and tracking using the configured RSA-CSI-RS configuration. The WTRU may continue to perform beam tracking for beam management using the configured RSA-CSI-RS configuration.

[0205] The WTRU may be configured with a set of PDSCH resources, i.e., RSA-PDSCH, to carry some or all of the MIB information and / or other system information. The WTRU may receive the RSA-PDSCH transmissions periodically, or alternatively, the WTRU may expect to receive an RSA-PDSCH transmission upon a trigger by the WTRU. The configured RSA-PDSCH resources may also include some resources for carrying some reference signals for timing / frequency tracking.

[0206] The downlink transmission scheme to support PDCCH transmission may be used in SFN deployments.

[0207] Some embodiments may enable multi-port PDCCH DM-RS. For a WTRU to properly receive PDCCH transmissions in an SFN deployment with multiple TRPs, the WTRU may need to perform channel estimation separately from multiple TRPs. However, current designs of PDCCH DM-RS may enable only one DM-RS port. Multiple DM-RS ports can be enabled using one or a combination of the following approaches, so that the WTRU can perform accurate channel estimation taking into account the PDCCH DM-RS transmitted from each TRP.

[0208] The WTRU can receive a combination of non-zero power DM-RS and zero power DM-RS from each TRP. In each figure, the DM-RS configuration is shown across one or two PRBs in the frequency domain and one slot in the time domain. If time-frequency resources for non-zero power DM-RS are configured for a TRP, the WTRU can receive a power-scaled version of the PDCCH DM-RS from the TRP. If time-frequency resources for zero power DM-RS are configured, the WTRU cannot receive any DM-RS from a particular TRP.

[0209] In order for the WTRU to process a combination of non-zero power DM-RS and zero power DM-RS from each TRP, the gNB can explicitly or implicitly indicate the DM-RS configuration. The indication can be based, for example, on RRC signaling (or another logically equivalent signal), on which TRS is used for carrier frequency estimation, on the TRP ID, or any combination thereof.

[0210] The WTRU may perform DM-RS estimation by considering the orthogonal cover code (OCC) used by each TRP when the duration of the PDCCH is two OFDM symbols as shown in FIG. 11. If the duration of the PDCCH is three OFDM symbols, the WTRU may use the assumed orthogonal OCCs to distinguish between the wireless signals received from the two TRPs. Alternatively, the WTRU may receive DM-RSs with different OCCs applicable to the two symbol durations from both TRPs. Furthermore, the WTRU may receive one additional DM-RS on the third OFDM symbol transmitted by one particular TRP.

[0211] The WTRU may perform DM-RS estimation based on the orthogonal / hypothetical orthogonal DM-RS signal sequences received from each TRP. To this end, a hypothetical random sequence generator may be uniquely initialized for each TRP. For example, if two TRPs transmit PDCCH in an SFN implementation, the PN sequence generation may be initialized by:

number

number

[0212] 8 illustrates zero-power and non-zero-power demodulation reference signal (DM-RS) configurations 800, 820 for a physical downlink control channel (PDCCH) transmission having one orthogonal frequency division multiplexing (OFDM) symbol duration. In the example configuration 800 for the first TRP, zero-power DM-RS symbols 802-806 and non-zero-power symbols 808-812 may alternate in the frequency domain 814 and occupy only the first symbol in the time domain 816.

[0213] In the exemplary configuration 820 of the second TRP, the non-zero power DM-RS symbols 822-826 may alternate with the zero power DM-RSs 828-832 in the frequency domain 834, while occupying only the first symbol in the time domain 836.

[0214] 9 shows first zero-power and non-zero-power DM-RS configurations 900, 920 for a PDCCH transmission having a two-OFDM symbol duration. In the first TRP example configuration 900, the non-zero-power DM-RS symbols 902-906 may precede the zero-power DM-RS symbols 908-912 in the time domain 916 but may occupy the same resources in the frequency domain 914.

[0215] In the exemplary configuration 920 of the second TRP, the zero-power DM-RS symbols 922-926 may precede the non-zero-power DM-RS symbols 928-932 in the time domain 936 but may occupy the same resources in the frequency domain 934.

[0216] 10 shows second zero-power and non-zero-power DM-RS configurations 1000, 1020 for PDCCH transmissions with a two-OFDM symbol duration. In the first TRP example configuration 1000, non-zero-power DM-RS symbols 1002-1006 may alternate with zero-power DM-RS symbols 1008-1012 in the time domain 1016 and occupy the same frequency resources in the frequency domain 1014.

[0217] In the second TRP exemplary configuration 1020, zero-power DM-RS symbols 1022-1026 may alternate with non-zero-power DM-RS symbols 1028-1032 in the time domain 1036 but may occupy the same resources in the frequency domain 1034.

[0218] 11 shows first zero-power and non-zero-power DM-RS configurations 1110, 1130 for a PDCCH transmission having a three-OFDM symbol duration. In the first TRP embodiment 1110, the non-zero-power DM-RSs 1102-1112 are placed before and after the zero-power DM-RS symbols 1114-1118 within a time period 1122. The non-zero-power DM-RSs may or may not be placed in the same frequency domain 1120 as the zero-power DM-RSs.

[0219] The second TRP configuration 1130 may use zero-power DM-RSs 1132-1142 along with non-zero-power DM-RS symbols 1146-1148 located between the zero-power DM-RS symbols 1132-1142 within a time period 1152. The non-zero-power DM-RS symbols 1146-1148 may or may not be located in the same frequency domain 1150 as the zero-power DM-RSs 1132-1142.

[0220] 12 is an illustration of second zero-power and non-zero-power DM-RS configurations 1200, 1250 for PDCCH transmissions having a three-OFDM symbol duration configuration. In the example configuration 1200, the zero-power DM-RS symbols 1202-1218 and the non-zero-power DM-RSs 1220-1236 may alternate in the time domain 1240 and the frequency domain 1238. In the example configuration 1250, the non-zero-power DM-RSs 1250-1268 and the zero-power DM-RS symbols 1270-1286 may alternate in the time domain 1290 and the frequency domain 1288.

[0221] 13 is an illustration of orthogonal cover code (OCC)-based DM-RS configurations 1300, 1320 for PDCCH transmission with a two-OFDM symbol duration. In configuration 1300, DM-RSs 1302-1312 are shown with OCC k spanning two OFDM symbols in the time domain 1316. The DM-RSs may be located within the same resource in the frequency domain 1314. In configuration 1320, DM-RSs 1322-1332 are shown with OCC j spanning two OFDM symbols in the time domain 1336. The DM-RSs may be located within the same resource in the frequency domain 1334.

[0222] Each of the configuration examples shown in FIGS. 8-13 is for illustrative purposes and is not intended to limit the embodiments.

[0223] Multiple TCI states may be activated for PDCCH reception. To receive PDCCH transmissions in an SFN implementation, two TCI states may be activated for CORESET. For this purpose, the TCI state indicator may be extended to define two TCI states for the same codepoint (one TCI state for each TRP). Based on the activated TCI state, the WTRU may determine the QCL relationship between the RS and the PDCCH DM-RS from each TRP.

[0224] In this case, the TCI state is not indicated to the WTRU, and the WTRU may assume that the antenna port associated with the PDCCH DM-RS is quasi-co-located with the corresponding SSB received from the respective TRP.

[0225] Dynamic switching between HST-SFN transmission schemes may be enabled. Switching between HST-SFN transmission schemes may be initiated by the WTRU or the network. If the WTRU wants to switch transmission schemes, it may indicate a switch request by transmitting a specific SRS from an SRS resource set preconfigured by the network. When the network switches transmission schemes, the WTRU may determine the transmission scheme based on one or more of the following approaches. In some approaches, the WTRU may determine the transmission scheme based on receiving two DM-RSs (HST-SFN downlink transmission scheme 2) or only one DM-RS (HST-SFN downlink transmission scheme 1). The WTRU may always attempt to estimate both DM-RSs and determine the presence of two or one DM-RS.

[0226] In some approaches, the WTRU may determine the HST-SFN downlink transmission scheme based on the configuration of the DM-RS of the CDM group. For example, if the DM-RS is configured from two CDM groups, the WTRU may determine that HST-SFN downlink transmission scheme 2 is enabled. If the DM-RS from two TRPs are configured from the same CDM group, the WTRU may determine that HST-SFN transmission scheme 1 is enabled.

[0227] In some approaches, the WTRU may determine the HST-SFN transmission scheme based on the TCI / QCL relationship between the PDSCH DM-RS and the TRS. For example, if each TRS is used as a source RS for TCI conditions and the PDSCH DM-RS is QCL'd with the TRS with Type A and Type D, the WTRU may determine that HST-SFN downlink transmission scheme 2 is enabled.

[0228] Although features and elements are described above in particular combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical 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

1. 1. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: receiving zone configuration information associated with one or more zones, each zone of the one or more zones having one or more zone identifiers (zone ids), and for each zone id of the zone ids, the configuration information indicates one or more of a beam reference signal (BRS), a set of transmission configuration indicator (TCI) states, a search space, or a control resource set (CORESET) configuration for receiving a physical downlink shared channel (PDSCH) transmission, or uplink resources; determining a zone id of the one or more zone ids based on one or more BRS measurements indicated via the configuration information; transmitting an indication of the determined zone id to a base station using uplink resources associated with the zone id.

2. The method of claim 1 , wherein the zone configurations of the zone configuration information are defined by geographic coordinates.

3. The method of claim 1 , wherein the determination of the zone id from among the one or more zone ids is further based on geographic coordinates of the WTRU.

4. The method of claim 1 , wherein each zone id is associated with a BRS.

5. 2. The method of claim 1, wherein each zone id is associated with a set of transmission configuration indicator (TCI) states for receiving physical downlink shared channel (PDSCH) transmissions.

6. The method of claim 1 , wherein each zone id is associated with a search space.

7. The method of claim 1 , wherein each zone id is associated with a control resource set (CORESET) configuration.

8. The method of claim 1 , wherein each zone id is associated with an uplink resource.

9. 1. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: receiving zone configuration information associated with one or more zones, each zone of the one or more zones having one or more zone identifiers (zone ids), and for each zone id of the zone ids, the configuration information indicates one or more of a beam reference signal (BRS), a set of transmit configuration indicator (TCI) states for receiving a physical downlink shared channel (PDSCH) transmission, a search space, a control resource set (CORESET) configuration, or uplink resources; determining a zone id of the one or more zone ids based on one or more BRS measurements indicated via the configuration information; monitoring a search space for a physical downlink control channel (PDCCH) transmission according to the determined zone-id search space configuration; receiving downlink control information (DCI) for the PDCCH transmission, the DCI indicating a TCI state for receiving a PDSCH transmission; determining a Reference Signal (RS) associated with the TCI state indicated by the DCI based on the determined zone id; receiving a PDSCH transmission using an associated PDSCH demodulation reference signal (DMRS) that is quasi-co-located with the determined RS; transmitting an indication of the determined zone id to a base station using uplink resources configured for the zone id.

10. The method of claim 9 , wherein the zone configurations of the zone configuration information are defined by geographic coordinates.

11. The method of claim 9 , wherein the determination of the zone id from among the one or more zone ids is further based on geographic coordinates of the WTRU.

12. The method of claim 9 , wherein each zone id is associated with a BRS.

13. 10. The method of claim 9, wherein each zone id is associated with a set of transmission configuration indicator (TCI) states for receiving physical downlink shared channel (PDSCH) transmissions.

14. The method of claim 9 , wherein each zone id is associated with a search space.

15. The method of claim 9 , wherein each zone id is associated with a control resource set (CORESET) configuration.

16. The method of claim 9 , wherein each zone id is associated with an uplink resource.

17. 1. A wireless transmit / receive unit (WTRU), comprising: a receiver configured to receive zone configuration information relating to one or more zones having one or more zone identifiers (zone ids), wherein for each zone id, the configuration information indicates one or more of a beam reference signal (BRS), a set of transmit configuration indicator (TCI) states for receiving a physical downlink shared channel (PDSCH) transmission, a search space, a control resource set (CORESET) configuration, or uplink resources; a circuit configured to determine a zone id of the one or more zone ids based on one or more BRS measurements indicated via the configuration information; and circuitry configured to indicate the determined zone id to a base station using uplink resources configured for the zone id.

18. 20. The WTRU of claim 17, further comprising: circuitry configured to monitor a search space or CORESET in accordance with a search space or CORESET configuration for the determined zone id for a physical downlink control channel (PDCCH) transmission.

19. 20. The WTRU of claim 18, further comprising the receiver configured to receive downlink control information (DCI) for the PDCCH transmission, the DCI indicating a TCI state for receiving a PDSCH transmission.

20. and further comprising a circuit configured to determine a Reference Signal (RS) associated with the TCI state indicated by the DCI based on the determined zone id; 20. The WTRU of claim 19, wherein the receiver is further configured to receive a PDSCH transmission using an associated PDSCH demodulation reference signal (DMRS) that is quasi-co-located with the determined RS.

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