Method and apparatus for multi-TRP transmission in HST scenarios

Abstract

The method and apparatus may include receiving zone configuration information associated with one or more zones having one or more zone ids. For each zone id of the zone ids, the configuration information may indicate one or more of a BRS, a set of TCI states for receiving PDSCH transmissions, a search space, a CORESET configuration, or uplink resources. The method may 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 may be transmitted to the base station using uplink resources associated with the zone id.

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 on February 13, 2020; U.S. Provisional Patent Application No. 63 / 061,293, filed on August 5, 2020; and U.S. Provisional Patent Application No. 63 / 094,745, filed on October 21, 2020, the contents of each of which are incorporated herein by reference.

Background Art

[0002] In New Radio (NR), the operation of Multi - Transmit / Receive Point (M - TRP) is initially focused on supporting downlink transmission. Thus, an NR WTRU can receive and process multiple NR Physical Downlink Control Channels (PDCCH) and NR Physical Downlink Shared Channels (PDSCH).

[0003] In NR Release 16, M - TRP transmission was developed to support M - TRP transmission of downlink shared data channels 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 PDSCH were agreed upon. The supported mechanisms are based on the use of additional resources in the spatial domain, frequency domain, and time domain. Depending on the scheme utilized, additional resources can be used to enable a lower code rate for transmission or support the repetition of the original transmission.

[0004] NR Release 17 may support enhancements for both the operation in Frequency Range 1 (FR1) and the operation in Frequency Range 2 (FR2). As one of the goals of NR Release 17, the enhancements in reliability and robustness developed for PDSCH in Release 16 may be extended to other physical channels such as PDCCH, PUSCH, and PUCCH. Such enhancements may utilize the use of M-TRP or multi-panel capabilities. Further, quasi co-location (QCL) and transmission configuration indicator (TCI) related enhancements for enabling inter-cell M-TRP with multiple DCI-based multi-PDSCH may be targeted. Also, beam management modes not studied in Release 16 may be developed.

SUMMARY OF THE INVENTION

[0005] A method and apparatus capable of receiving zone configuration information related to one or more zones having one or more zone identifiers (zone IDs). For each zone ID of the zone IDs, the configuration information may indicate one or more of a beam reference signal (BRS), a set of transmission configuration indicator (TCI) states for receiving physical downlink shared channel (PDSCH) transmissions, a search space, a control resource set (CORESET) configuration, or uplink resources. The method may further include determining a certain zone ID among the one or more zone IDs based on measurement values of one or more BRSs indicated via the configuration information. An indicator of the determined zone ID may be transmitted to a base station using uplink resources associated with the zone ID.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A more detailed understanding can be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals in the figures indicate like elements.

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[0007] FIG. 1A is a diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 can be a plurality of access systems that provide content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 can enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 can 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 filter type OFDM, filter bank multicarrier (FBMC).

[0008] As shown in Figure 1A, communication 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 is understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d can 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, each of which may be referred to interchangeably as a station (STA), can be configured to transmit and / or receive wireless signals and can include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscriber-based units, pager, cellular phone, personal digital assistant (PDA), smartphone, laptop, netbook, personal computer, wireless sensor, hotspot or Mi-Fi device, Internet of Things (IoT) device, watch or other wearable, head-mounted display (HMD), vehicle, drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d can be referred to interchangeably as a WTRU.

[0009] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN 106, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), NodeB, eNode B (eNode B, eNB), home NodeB, home eNode B, next generation NodeB (gNode B, gNB) such as gNode B, new radio (NR) NodeB, site controller, access point (AP), wireless router, etc. Although base stations 114a, 114b are each shown as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0010] Base station 114a can be part of RAN104, which can also include other base stations such as a base station controller (BSC), a radio network controller (RNC), a relay node, and / or network elements (not shown). Base station 114a and / or base station 114b can be configured to transmit and / or receive radio signals at one or more carrier frequencies that can be referred to as a cell (not shown). These frequencies can be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell can provide wireless service coverage to a specific geographic area that can be relatively fixed or can change over time. A cell can further be divided into cell sectors. For example, the cell associated with base station 114a can be divided into three sectors. Thus, in one embodiment, base station 114a can include three transceivers, i.e., one for each sector of the cell. In one embodiment, base station 114a can use multiple-input multiple output (MIMO) technology and can utilize multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0011] Base stations 114a, 114b can communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0012] More specifically, as described above, the communication system 100 can be a plurality of access systems and can use one or more channel access methods 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 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) that can establish an air interface 116 using wideband CDMA (WCDMA). WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed Uplink (UL) Packet Access (HSUPA).

[0013] In one embodiment, the base stations 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can establish an 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 stations 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can establish an air interface 116 using NR.

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

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

[0017] The base station 114b in Fig. 1A may be, for example, a wireless router, a Home NodeB, a Home eNode B, or an access point, and can utilize any suitable RAT to facilitate wireless connection in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for use by drones, for example), a road, or other locations. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless 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 can implement a wireless 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 can utilize a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. 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 via the CN 106 in some cases.

[0018] RAN 104 can communicate with CN 106, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of 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. CN 106 can provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video delivery, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A, it will be understood that RAN 104 and / or CN 106 can communicate directly or indirectly with other RANs using the same RAT or a different RAT as RAN 104. For example, in addition to being connected to RAN 104, which may utilize NR radio technology, CN 106 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] CN106 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN 108 may include a public switched telephone network that provides 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 network 112 may include wired and / or wireless communication networks that are owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs that can use the same or a different RAT as the RAN 104.

[0020] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include multimode capabilities (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 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 IEEE802 wireless technology.

[0021] Figure 1B is a system diagram showing an exemplary WTRU 102. As shown in Figure 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, a non-removable memory 130, a removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU 102 may include any partial combination of the foregoing elements while remaining consistent with one embodiment.

[0022] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. The processor 118 can perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120 that can be coupled to a transmit / receive element 122. Although Figure 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 can 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) via 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, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical 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] Although the transmit / receive element 122 is depicted in FIG. 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 via 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 noted 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 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) and can receive user input data therefrom. The processor 118 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Further, the processor 118 can access information from and store data in any suitable type of memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 can include a random-access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 can include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 can access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

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

[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) via the air interface 116 and / or may determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with one embodiment.

[0029] The processor 118 may further be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 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 peripheral devices 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor, etc.

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

[0031] FIG. 1C is a system diagram showing the RAN 104 and the CN 106 according to one embodiment. As described above, the RAN 104 can communicate with the WTRU 102a, 102b, 102c via the air interface 116 using the E-UTRA radio technology. The RAN 104 can also communicate with the CN 106.

[0032] The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with one embodiment. Each of the eNode-Bs 160a, 160b, 160c may include one or more transceivers for communicating with the WTRU 102a, 102b, 102c via the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, can transmit a wireless signal to the WTRU 102a and / or receive a wireless signal from the WTRU 102a using multiple antennas.

[0033] Each of eNode-Bs 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling, etc. in UL and / or DL. As shown in FIG. 1C, eNode-Bs 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0034] CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing elements are shown as part of 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] MME 162 can be connected to each of eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can function as a control node. For example, MME 162 can authenticate WTRUs 102a, 102b, 102c, users with bearer activation / deactivation, and can play a role in selecting a specific serving gateway during the initial attach of WTRUs 102a, 102b, 102c. MME 162 can provide control plane functions for switching between RAN 104 and other RANs (not shown) using other radio technologies such as GSM and / or WCDMA.

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

[0037] The SGW 164 can be connected to the PGW 166, and the PGW 166 can provide the WTRUs 102a, 102b, and 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, and 102c and IP - enabled devices.

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

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

[0040] In an exemplary 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 an access or interface to a distribution system (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic to an STA originating from outside the BSS may reach and be delivered to the STA through the AP. Traffic originating from an STA to a destination outside the BSS may be sent to the AP and then sent to each destination. Traffic between STAs within the BSS may be sent, for example, via the AP, where the source STA may send the traffic to the AP and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be regarded as and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent in a direct link setup (DLS) between the source STA and the destination STA (e.g., directly between them). In certain exemplary embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using 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 the "ad hoc" communication mode.

[0042] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may transmit beacons on a fixed channel such as the primary channel. The primary channel may have a fixed width (e.g., a 20 MHz bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STA 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. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) may sense the primary channel. If the primary channel is sensed / detected as busy by a particular STA and / or determined to be so, the particular STA may back off. Only one STA (e.g., only one station) may transmit at any given time in a given BSS.

[0043] A High Throughput (HT) STA may form a 40 MHz wide channel for communication, for example, through a combination of the primary 20 MHz channel and adjacent or non - adjacent 20 MHz channels.

[0044] A Very High Throughput (VHT) STA may support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz may be formed by combining consecutive 20 MHz channels. A 160 MHz channel may be formed by combining eight consecutive 20 MHz channels or by combining two non - consecutive 80 MHz channels, which may be referred to as an 80 + 80 configuration. In the case of 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] The sub-1 GHz operating mode is supported by 802.11af and 802.11ah. The channel operating bandwidth and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to an exemplary embodiment, 802.11ah may support meter type control / machine-type communications (MTC), such as MTC devices in a macro coverage area. The MTC device may have limited capabilities, including support (e.g., only support therefor) for a specific and / or limited bandwidth. The MTC device may include a battery having a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0046] A WLAN system that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes channels that can be designated as primary channels. The primary channel may 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 set and / or restricted by the STA among all STAs operating in a BSS that supports the minimum bandwidth operation mode. In the example of 802.11ah, the primary channel is 1 MHz wide for an STA (e.g., an MTC type device) that supports the 1 MHz mode (e.g., supports only that) even when the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or Network Allocation Vector (NAV) setting may depend on the state of the primary channel. For example, when the primary channel is busy, even if most of the available frequency band becomes idle by an STA transmitting to the AP (supporting only the 1 MHz operation mode), all of the available frequency band may be considered busy.

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

[0048] FIG. 1D is a system diagram showing RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, 102c via air interface 116 using NR radio technology. RAN 104 can also communicate with CN 106.

[0049] RAN 104 may include gNBs 180a, 180b, and 180c, although it will be understood that RAN 104 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 108b may utilize beamforming to transmit and / or receive signals to / from gNBs 180a, 180b, and 180c. Thus, gNB 180a, for example, may transmit a radio signal to WTRU 102a and / or receive a radio signal from WTRU 102a using multiple antennas. In one embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, and the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0050] WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using transmissions associated with an extensible numerology. For example, the OFDM symbol interval and / or the OFDM sub-carrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or extensible lengths (e.g., including various numbers of OFDM symbols and / or continuously varying times of various absolute lengths).

[0051] gNBs 180a, 180b, and 180c may be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c, etc.). In a stand-alone configuration, WTRUs 102a, 102b, and 102c may utilize one or more of gNBs 180a, 180b, and 180c as a mobility anchor point. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with and connecting to another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c may implement a DC principle for communicating with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c substantially simultaneously. In a non-stand-alone configuration, eNode-Bs 160a, 160b, and 160c may function as a mobility anchor for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, and 102c.

[0052] Each of gNBs 180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slices, DC, interaction 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, gNBs 180a, 180b, and 180c may communicate with each other via the Xn interface.

[0053] CN 106 shown in FIG. 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 optionally data networks (DNs) 185a, 185b. Although the foregoing elements are shown as part of CN 106, it will be understood that any of these elements may be owned and / or operated by entities other than the CN operator.

[0054] AMF182a and 182b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N2 interface and can function as control nodes. For example, AMF182a and 182b can perform roles such as user authentication of WTRU102a, 102b, and 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selection of the registered SMF183a and 183b, management of the registration area, termination of non-access stratum (NAS) signaling, and mobility management. Network slicing can be used by AMF182a and 182b to customize the CN support for WTRU102a, 102b, and 102c based on the type of services utilized by WTRU102a, 102b, and 102c. For example, different network slices can be established for different use cases such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, and services for MTC access. AMF182a and 182b can provide control plane functions for switching between RAN104 and other RANs (not shown) that use other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0055] SMF183a and 183b can be connected to AMF182a and 182b in CN106 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN106 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic passing through UPF184a and 184b. SMF183a and 183b can perform other functions such as the function of managing and allocating WTRU IP addresses, the function of managing PDU sessions, the function of implementing policies and controlling QoS, and the function of providing DL data notifications. The PDU session type can be IP-based, non-IP-based, Ethernet-based, etc.

[0056] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N3 interface, which can provide access to a packet-switched network such as the Internet 110 to WTRU102a, 102b, and 102c to facilitate communication between WTRU102a, 102b, and 102c and IP-corresponding devices. UPF184 and 184b can perform other functions such as packet routing and forwarding, implementation of user plane policies, support for multi-home PDU sessions, processing of user plane QoS, buffering of DL packets, and mobility anchoring.

[0057] CN106 may facilitate communication with other networks. For example, CN106 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN106 and the PSTN108. Further, CN106 may provide access to other network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers, to the WTRU102a, 102b, 102c. In one embodiment, the WTRU102a, 102b, 102c may be connected to the local DN185a, 185b through the UPF184a, 184b via an N3 interface to the UPF184a, 184b and an N6 interface between the UPF184a, 184b and the DN185a, 185b.

[0058] In view of FIGS. 1A-1D and the corresponding descriptions of FIGS. 1A-1D, one or more or all of the functions described herein with respect to one or more of the WTRU102a-d, base stations 114a-b, eNode-B160a-c, MME162, SGW164, PGW166, gNB180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN185a-b, and / or any other device described herein may be performed by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functionality.

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

[0060] One or more emulation devices can execute one or more functions including all while not being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device can be utilized in a test scenario in a test laboratory and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing) to implement tests of one or more components. One or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which can include one or more antennas) can be used by an emulation device to transmit and / or receive data.

[0061] In Release 15NR, one or more control resource sets (CORESETs) can be configured for each bandwidth part (BWP), and each CORESET can be composed of one or more beam reference signals via radio resource control (RRC) signaling. The beam reference signal can be either a non-zero power channel state information reference signal (NZP-CSI-RS) that may include an NZP-CSI-RS resource ID, or a synchronization signal block (SSB) signal that may include an SSB index. The beam reference signal can be indicated within 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 index of the beam reference signal can be signaled via a transmission configuration indicator (TCI) state.

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

[0063] One or more PDCCH search spaces can be associated with the CORESET, and the WTRU can 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) can be indicated as a reference signal index having a QCL type D. The BRS can 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 can be used by a WTRU to report CSI can be controlled by a 5G NodeB or a next-generation NodeB. CSI can consist of, or be composed of, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), an 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 can operate based on three main configuration objects, which are one or more lists of CSI-ReportConfig, CSI-ResourceConfig, and trigger states. CSI-ReportConfig can include a report setting of N ≧ 1, in which details related to the measurement reporting mechanism are incorporated. CSI-ResourceConfig can include M ≧ 1 different resource settings that can be combined with at least one of the N report settings.

[0067] The list of trigger states may include two options, namely, CSI-AperiodicTriggerStateList and CSI-SemiPersistentOnPUSCH-TriggerStateList, each of which may include at least one trigger state associated with a defined CSI-ReportConfigs configuration.

[0068] Figure 2 shows two exemplary scenarios 200, 220 for the operation of a downlink M-TRP. 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 in which separate layers 210, 212 are transmitted from separate TRPs 202a, 202b.

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

[0070] Figure 3 shows an HST-SFN scenario 300 in which M-TRP deployment can spread along the orbital path 302 to provide services to the train 304. The first cluster of TRPs may include TRPs 306-310 connected to a baseband unit (BBU) 312. The second cluster of TRPs may include TWPs 314-318 connected to the BBU 320. The BBU may refer to a unit that processes the baseband of a communication system. A typical radio communication station is composed of a BBU and one or more remote radio units. These remote radio units are shown as TRPs in Figure 3. The baseband unit may be connected to the TRP via an optical fiber and may play a role in communication via a physical interface.

[0071] Embodiments directed to determining TCI states based on zones are described herein. One or more zones may be defined, configured, or used in an HST-SFN network. The zones may be configured or determined based on the geographical coordinates (e.g., longitude and latitude) of the WTRU, and the zones 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 can determine the associated zone (or zone id) based on the geographical coordinates of the WTRU (e.g., the geographical coordinates of the WTRU being within the corresponding range).

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

[0074] In some embodiments, the zone can be configured based on the wireless coverage of the cell. For example, the WTRU can determine the zone based on the downlink measurement values of one or more beam reference signals from one or more TRPs or cells. Hereinafter, the zone can be used interchangeably with area, position, and positioning.

[0075] In some embodiments, the WTRU can receive a configuration of the association between a TCI state (or TCI state group) and a zone. For example, one or more TCI states can be associated with a zone (or zone id), and the association information can be configured via upper layer signaling. In such a scenario, one or more of the following procedures can be implemented. For example, the WTRU can determine a TCI state for downlink reception and / or uplink transmission based on the determined zone id. For example, the WTRU can first determine the zone id based on the geographical coordinates of the WTRU, and the WTRU can 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. The corresponding beam reference signal of the TCI state (e.g., SSB index, CSI-RS index, SRS resource index) can be determined based on the zone id. For example, the WTRU can receive the TCI state of the DCI for downlink or uplink transmission, and the WTRU can interpret the TCI state differently based on the determined zone id. When the first zone id is determined, the first beam reference signal can be used for the TCI state, and when the second zone id is used, the second beam reference signal can be used for the TCI state. One or more N-bit TCI state fields can be used in DCI scheduling for downlink or uplink transmission, 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 the first zone id is determined, the first set of TCI states can be used for the N-bit TCI state field, and when the second zone id is determined, the 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 the determined zone id of the WTRU to a NodeB (e.g., gNB). For example, the WTRU may send or report the determined zone id when the zone id is changed. For example, the WTRU may report the updated zone id when the WTRU detects a change in the associated zone id. In some cases, the updated zone id report may be indicated in PUSCH, PUCCH, MAC-CE, or RRC. In some cases, each zone id may be associated with an uplink channel (e.g., PRACH, PRACH sequence, PUCCH resource, PUSCH resource, SRS resource), and the WTRU may send the associated uplink channel based on the determined zone id.

[0077] In some embodiments, the CORESET may be configured with one or more TCI states, and one of the TCI states may be determined or used at a time for monitoring the associated PDCCH search space. The WTRU may determine one of the TCI states of the CORESET based on the determined zone ID. In some embodiments, the TCI state associated with the 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 corresponding to the determined zone id. For example, the WTRU may be composed of one or more CORESETs, each CORESET may be associated with one or more zone ids, and thus, the subset of the CORESET may be determined based on the determined zone id.

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

[0080] Figure 4A shows an HST-SFN scenario 400 in which the cluster deployment of M-TRPs, including TRP404 - 408 and TRP412 - 416, can be spread along the track path of train 402. To increase robustness and also reduce signaling associated with handover, the HST-SFN scenario 400 can use an architecture based on the cluster deployment of M-TRPs. Thus, embodiments and enhancements related to the QCL assumption, TCI framework, control channel design, and CSI framework can be advantageous to support the HST-SFN deployment scenario.

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

[0082] For example, if the WTRU is located on train 402 and is served by one or more of TRP404 - 408, the WTRU can determine a zone id 410 of n. If the WTRU is served by one or more of TRP412 - 416, the WTRU can determine a zone id 418 of m. For the zone id of n, the WTRU can be configured with one or more first beam RSs, a set of TCI states, an SS / CORESET configuration, and uplink resources. For the zone id of m, the WTRU can be configured with a second set of configuration parameters including one or more second beam RSs, a set of TCI states, a second SS / CORESET, and a second UL resource. The zone id can be determined from among the configured zone ids based on measurements of one or more BRSs from among at least one BRS configured for each zone id and the geographical coordinates of the WTRU.

[0083] Figure 4B is a flowchart 420 showing a procedure for determining a TCI state using a zone configuration. The procedure can be summarized as follows. A WTRU can receive one or more zone configurations (e.g., defined by geographical coordinates), each identified by an ID, e.g., a zone id (422). For each zone id, the WTRU can 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 can determine a zone id from among the configured zone ids based on measurements of one or more BRSs from among at least one BRS configured for each zone id and the geographical coordinates of the WTRU (426).

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

[0085] In one embodiment, one enhancement may involve an efficient update of TCI / QCL information. In NR, a quasi-collocation (QCL) relationship may refer to the spatial quasi-collocation of reference signals. The QCL relationship can be expressed with respect to delay spread, average delay, Doppler spread, Doppler shift, or spatial Rx parameters. TCI can carry information regarding the reference signal antenna ports with which a particular PDCCH or PDSCH (DMRS) antenna port is quasi-located (``QCLed'').

[0086] In some embodiments, the 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 within the corresponding CORESET. A particular TCI state may be dynamically signaled by the WTRU through MAC signaling. A TCI state may be composed of at least one combination of a serving cell, bandwidth part identification information, and at least one reference signal. The at least one reference signal may be a CSI-RS or an SSB. The WTRU may assist in receiving PDCCH or PDSCH transmissions by assuming a quasi-collocation relationship that exists between a port of such a reference signal and a DM-RS port. This may be, for example, for setting or selecting a spatial filter and for estimating timing and Doppler spread and / or shift. The configuration of multiple reference signals of a TCI state may enable the WTRU to select the most appropriate spatial filter in a scenario where a channel (e.g., PDCCH or PDSCH) is received from multiple TRPs or beams in an SFN-like manner. Such a TCI state may be referred to as a "multi-beam" TCI state.

[0087] Alternatively, a group of TCI states may be provided to the WTRU for the purpose of PDCCH or PDSCH reception instead of a single TCI state, and the WTRU may assume that the same information is transmitted on all DM-RS ports that are quasi-collocated with ports of the reference signals 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 herein as a "TCI information vector" as described herein.

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

[0089] The channels can be partitioned and TCI information vectors can 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 regarding the downlink reference signal, such as the beam and DMRS ports, from the configured TCI vectors configured for its zone. In some embodiments, the WTRU can be configured with different types of TCI configurations for each zone.

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

[0092] In one embodiment, the WTRU can be composed of two or more TCI information vectors, and each vector can have a different length from the other vectors. The WTRU can identify each TCI information vector using an index.

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

[0094] In the dynamic mode, the WTRU may receive an information element and determine the TCI information vector of a zone having DCI or MAC CE. The WTRU may decode the received information element and determine the index of the TCI information vector. The metric may determine the TCI information vector of the neighboring zone. The neighboring 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 composed of a sequence of indexes representing the index of the TCI vector for each zone. The WTRU may receive a single-bit DCI or MAC-CE and indicate an increment within the configured sequence so as to indicate the next zone. The neighboring 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 the semi-static mode, in addition to a set of TCI information vectors, the WTRU may be composed of other information to assist in determining the TCI information vector of each zone. In some embodiments, the WTRU may be composed of a geolocation table that associates some or all zones with an index whose index represents the TCI information vector. The WTRU may determine the TCI information of the zone by comparing the geolocation with the index configured in the table. Alternatively, the WTRU may be composed of a sequence of indexes whose each index represents the index of the TCI information vector. The WTRU may determine the TCI information vector of the zone by referring to 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] Embodiments directed to conditional reconstruction of a set of TCI information vectors or a set of TCI states are disclosed herein. In some embodiments, to facilitate fast and large-scale reconstruction, a WTRU can apply conditional reconstruction 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 can 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 can be configured with at least one measurement configuration for each target set of TCI states or information vectors. When a measurement report is triggered based on such a configuration, the WTRU can reconstruct the current set of TCI states or TCI information vectors as the corresponding target set. The WTRU can apply a default or initial TCI state or TCI information vector from among the reconstructed set of TCI states or TCI information vectors for decoding of PDCCH and PDSCH immediately after reconstruction. The WTRU can also be signaled a target SRS configuration for each target set of TCI states or information vectors and can reconstruct SRS according to the corresponding target set.

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

[0098] At the time of NR Release 16, at least four different QCL types, namely, types A, B, C, and D, can be defined. The QCL information can define which properties of the channels observed by one set of antenna ports can be accurately maintained for another set of antenna ports. For example, QCL type C can indicate that only the values of the average delay and Doppler shift observed by one set of antenna ports can be assumed for the corresponding QCLed counterparts (and vice versa). However, if two sets of antenna ports are QCLed with type A, it can be assumed that, in addition to the average delay and Doppler shift, both channels experience similar values of Doppler spread and delay spread.

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

[0100] In some embodiments, a fast WTRU can receive such an indication for transmission ports of different panels of the same TRP. For example, when the WTRU passes through the TRP, it can know how to efficiently adapt from a positive Doppler shift to a negative Doppler shift.

[0101] The WTRU can receive new QCL configuration information that includes information regarding the transmit port that results in a Doppler shift opposite to that of the high-speed WTRU. For example, one or more QCL configurations of the high-speed WTRU in a multi-TRP system can be considered. Such configurations can include QCL-Type A_n that can specify the opposite Doppler shift, Doppler spread, average delay, and delay spread, QCL-Type B_n that can specify the opposite Doppler shift and Doppler spread, QCL-Type C_n that can specify the opposite Doppler shift and average delay, QCL-Type E_n that can specify the opposite Doppler shift and delay spread, and QCL-Type F_n that can specify the opposite Doppler shift, among others.

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

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

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

[0105] The beam used for one or more CORESETs can be determined in the HST scenario. In some embodiments, one or more Beam Reference Signals (BRS) can be used or configured, and each Beam Reference Signal (BRS) can be configured with a BRS index. The gNB can configure a set of BRS indexes that can be associated with the CORESET. For example, the CORESET can have a plurality of associated BRS indexes, and one of the BRS indexes can be determined based on a time index. For example, the time index can 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 can determine the BRS of the CORESET, and the determined BRS can be valid within a specific time window. The time window can be a set of consecutive OFDM symbols, slots, subframes, radio frames, or hyperframes. For example, if N time windows are configured, defined, or in use, each time window can be composed of the BRS of the CORESET. The WTRU can determine the BRS index within the configured BRS index 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 can be configured for the CORESET, and a set of BRSs can be indexed in ascending order. For example, if N BRSs are configured, the set can be represented as BRS 1 , BRS 2 ,..., BRS N . The first BRS can be determined for the time window based on the measurement value of the BRS. For example, the WTRU can determine the first BRS index of the first time slot based on the RSRP measurement of the configured BRS. The BRS with the highest RSRP can be determined as the first BRS index. If the first BRS index is x, the next BRS index for the next time window can be determined based on a predetermined order. For example, (x + 1) modulo N can be used as the BRS index of the CORESET in the next time window. The BRS index k of time window m can 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 upon receiving confirmation from the gNB, the reported BRS index and subsequent BRS indices can be used.

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

[0109] The beam can be determined for one or more CORESETs using a zone-based beam approach. In some embodiments, one or more BRS can be used or configured for the CORESET. For a CORESET within a slot for monitoring one or more associated search spaces, one or more of the beam reference signals can be determined, and the WTRU can determine the BRS based on the geographical location of the WTRU.

[0110] In one example, one or more zones can be defined, configured, or used, and each zone can be configured with a range of longitude and latitude on the map. The WTRU can determine the corresponding zone based on the current geographical location of the WTRU, for example, via global positioning satellite signaling. The configured zones may not overlap at the longitude and latitude points within the map, and thus there may be no ambiguity in determining the zone for a given geographical location. One or more zones can be configured based on one or more characteristics.

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

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

[0113] For example, a WTRU can 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 signals such as MIB or SIB, or dynamic signaling such as DCI.

[0114] A WTRU can determine a zone id for monitoring one or more search spaces or for receiving a scheduled PDSCH transmission within a slot associated with a CORESET. The CORESET may initially be configured with a TCI state for determining a beam reference signal, and when the zone id is determined or used, the configured TCI state may be overridden by the beam reference signal determined by the zone id.

[0115] A WTRU can first determine a zone before receiving a downlink signal such as a PDCCH or PDSCH transmission or a reference signal of a slot, and then the WTRU can determine a beam for receiving the downlink signal. The WTRU can receive one or more downlink signals using the determined beam. In some embodiments, a WTRU or group of WTRUs may report the currently associated zone id of the WTRU or group of WTRUs. From the reported zone id, the gNB may be notified of the geographical location and direction of movement 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 when the associated zone id of the WTRU changes, when the WTRU receives a reporting trigger message, e.g., via DCI or MAC-CE, when the currently assigned or determined beam quality is below a threshold, where the beam quality may be based on at least one of RSRP, assumed BLER, or signal to interference plus noise ratio (SINR) of a beam reference signal, or when 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 example, a set of PUCCH resources may be configured and one of the PUCCH resources may be determined as a function of the zone id, WTRU id, or cell id. Hereinafter, the term zone may be used interchangeably with zone, cluster, or region.

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

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

[0118] In one embodiment, the WTRU can be configured with two or more search spaces having the same or different CORESETs, and each search space can be assigned to a different zone. In an exemplary embodiment, the WTRU can be configured with two search spaces that can alternate between odd - numbered and even - numbered zone ids.

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

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

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

[0122] In some cases, the WTRU that determines the group id can perform group-based beam management operation modes and can stop performing WTRU-specific beam management operations. The WTRU can notify the gNB and its associated quality regarding the reception of the proximity reference signal, for example, by providing an RSRP level. Alternatively, the WTRU can notify the gNB of the determined group id. The gNB can confirm that the WTRU can use group-based beam management operation modes.

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

[0124] Embodiments directed to inter-cell HST and beam selection are described herein. When a WTRU is moving at high speed within a train along a track, one problem involved can be handing over the WTRU between cells, for example, in an inter-cell M-TRP scenario. Performing a handover at high speed with low latency can pose challenges regarding measurements, configurations, and PDCCH monitoring from different cells with very different Doppler shifts. Another problem can be the volume of almost simultaneous handovers from WTRUs in the same location within a train / cargo. Therefore, it is important to reduce the overhead of this type of signaling.

[0125] In some embodiments, the WTRU can support monitoring of multi-TCI states. In this way, the WTRU can handle PDCCH from different cells almost immediately. When the WTRU moves from one TRP cluster to the next, the following cell PCIs can be configured for mobility measurements such that the next one is associated with a different cell with a different physical cell ID (PCI). In some cases, a high Doppler difference gap may be required for intra-frequency measurements. In some embodiments, when a gap is configured, SMTC can align with an SSB or CSI-RS burst, and thus the latency for cell and beam detection can be optimized.

[0126] While the WTRU is performing these measurements, in some embodiments, the gap can align with a specific PCI-SSB index of the detected beam, so that the WTRU can measure and sweep faster through the beam index and have sufficient samples to make a sound decision to activate the specific TCI state and CORESET associated with the cell.

[0127] In some embodiments, the WTRU may be semi-statically configured in a TCI state between both PCI-related cells belonging to both clusters, and based on a measurement threshold, may configure a conditional handover that will monitor a specific target CORESET / PDCCH group.

[0128] In some embodiments, when the SSB index can be evenly spread across the TRP clusters, the WTRU can start 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. Detection of the detected PCI / SSB index of the target over a specific threshold may automatically indicate the activation of an already configured TCI belonging to the target inter-cell TRP.

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

[0130] When the network is fully synchronized with slot and frame boundaries, enabling common WTRU processing at the symbol / slot level, overlapping PDCCH problems can be completely avoided within the time domain. In some embodiments, when the WTRU correctly receives / decodes the target cell PDCCH and subsequently the PDSCH transmission, it can signal the network of handover completion or simply start to approve the PDSCH transmission from the target cell. Upon receiving the ACK or CSI feedback of the target cell, the network can consider the handover completion. The subsequent configuration for the next cell can then be sent to the WTRU along with the 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, which means that a specific number of cells / SSBs can be configured in sequence. The WTRU can cycle through such a configuration and perform all handovers conditionally. This can be done by the WTRU with only the cell sequence, along with the attached thresholds, SSB index, and PCI, without other single-cell-based semi-static configurations. In embodiments, conditional handovers 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 the measurements related to the next target cell, reducing power consumption and cell / beam index detection time, both of which can be important in the HST scenario.

[0132] In some embodiments, an improved CSI framework can be applied in the context of an HST. In NR, the CSI framework can operate based on the following three main constituent objects: CSI-ReportConfig, CSI-ResourceConfig, and a list of trigger states. The HST WTRU can be configured such that one or more CSI constituent objects are dependent on the HST zone or TRP. Further, one or more detailed configurations of each object can be dependent on the zone or TRP.

[0133] In some embodiments, the WTRU can be configured with a CSI-ResourceConfig that includes multiple resource settings, where each setting can be linked to a zone or TRP. The WTRU can be configured to perform CSI measurements on the configured resources when the WTRU detects the corresponding zone or TRP beam.

[0134] In some embodiments, the WTRU can be configured with a CSI-ReportConfig that includes multiple reporting settings, where each setting can be linked to a zone or TRP. The WTRU can be configured to report CSI according to the configured reporting settings when the WTRU detects the corresponding zone or TRP beam.

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

[0136] The CSI-RS configuration can use the same set of RS for all segments. The CSI-RS configuration can have two or more CSI-RS sets, such 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 constituent object and the zone or TRP can be indicated in an implicit or explicit manner. In the case of an implicit indicator, the WTRU can determine that the CSI configuration corresponds to a zone or TRP according to a broadcast indicator or a common control indicator. In one such embodiment, the WTRU can be configured with a common CORSET dedicated to all HST WTRUs. For example, the HST CORESET can be used to receive all relevant information of all WTRUs within a zone. If the HST CORESET is not configured, the WTRU can use CORESET0 to obtain HST zone and TRP information. In some cases, the HST CORESET can indicate some additional relevant information, such as the identification information of the current zone or TRP, and the number of TRPs within the zone.

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

[0139] The CSI-RS report can be implemented in an efficient manner. In the HST scenario, many WTRUs can be grouped under the same mobility conditions, and thus all of the WTRUs can experience and share a very similar high Doppler or short coherence time for the corresponding radio channels of the WTRUs. In the HST scenario with many WTRUs, it may not be feasible to report CSI at high speed for each WTRU due to excessive feedback overhead and excessive use of system resources.

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

[0141] The WTRU can be configured to report the CSI information of the WTRU, such as Doppler information, on behalf of other WTRUs within the HST vehicle. The WTRU can report the CSI of the WTRU using one or more of the following mechanisms. For example, in some cases, the WTRU can be configured with a set of CSI-RS resources and can report the CSI report of the WTRU based on a random function. Since the number of WTRUs within the HST vehicle can change, the WTRU can be configured with additional parameters to bias the random function according to the stationary time of the channel and maintain a reasonable collision rate with reports from other WTRUs. In some cases, the WTRU can be configured to report the CSI information of the WTRU, such as Doppler information, only in a specific zone pre-configured by a list. This configuration may also include CSI resource configuration for each zone. In other cases, the WTRU or a group of WTRUs can be triggered to report the CSI information of the WTRU or the group of WTRUs, such as Doppler information, only when indicated by a common DCI or MAC-CE. In the case of a group call, the WTRU can use the same or different CSI resources for measurement purposes.

[0142] The CSI-RS configurations of multiple TRPs can be reused. The CSI-RS resources can be used in beam management procedures where the CSI-RS is beamformed in different directions, or can be used for codebook or non-codebook based precoding. To avoid excessive RRC reconfiguration overhead when the WTRU rapidly moves from one TRP to another, a common CSI-RS configuration can be configured collectively for a group of TRPs. For example, the TRPs can be arranged along a train track such that the same beam direction can be reused at each TRP. The beam direction can be preconfigured based on the geographical installation of the TRPs with respect to the movement of the train. The WTRU can assume that a set of the same beam directions is available for all TRPs having the same CSI-RS configuration.

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

[0144] The set of active TRPs can be indicated by a zone index representing a zone of the track. The zone index can be linked to a set of TRPs belonging to the same geographical area. The zone index can be included as part of the CSI-RS configuration, and the WTRU can determine the effective CSI-RS configuration based on the geographical location of the WTRU, determined, for example, via GPS signaling, and can link it to the TRPs belonging to the geographical area.

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

[0146] The 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 can limit its monitoring to only the set of active CSI-RS, and each TRP may not need to signal to the WTRU if the set is active when the WTRU is pre-configured with the pattern. The pattern may consist of, or be configured from, a sequence of TRPs for which each set is active, a sequence of geographical areas indicating which set is active in which area, or a timer associated with each set that determines the period during which the set is active.

[0147] Figure 5 shows the movement 502 of the WTRU along the trajectory 504. In the illustrated embodiment, the odd-numbered TRPs, including TRP1 506 and TRP3 508, may be located north of the trajectory 504. TRP1 506 and TRP3 508 may have beams pointing south. The even-numbered TRPs, including TRP2 510, may be located south of the trajectory, and the beams point north. The pattern can be configured in the WTRU512 such that one set of CSI-RS can be active for the odd-numbered TRPs while the other set of CSI-RS can be active for the even-numbered TRPs. The WTRU can adjust its receive / transmit beam according to the TRP index detected when the WTRU moves. For example, the WTRU can face the side with the odd TRPs, and the WTRU can determine to activate only the panel of the WTRU that faces the odd TRPs. Alternatively or in combination, TRP1 506 and TRP3 508 can be configured in the same geographical area, and TRP2 510 can be configured in a different area. When the WTRU enters the geographical area of TRP2 510, the WTRU can determine to change the spatial transmit / receive filter of the WTRU to match the active CSI-RS configuration within the geographical area of TRP2 510.

[0148] The CSI-RS resource can be triggered on a TRP different from where the trigger signal is sent. When the WTRU moves at high speed, one TRP may send a control signal to trigger the aperiodic CSI-RS, and there may not be enough time for the WTRU to send the CSI-RS before the WTRU moves. Further, the WTRU may require 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 resource can be triggered by a control signal on one TRP, the aperiodic CSI-RS resource can be sent on another TRP. The trigger control signaling may include a TRP index indicating the TRP that can send the AP-CSI-RS, an offset index n indicating the TRP having an index offset by n from the trigger 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 can determine from the trigger message, and thereby 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. The aperiodic trigger may be performed by DCI or MAC CE. For example, in FIG. 5, TRP1 506 may send DCI to the WTRU that triggers aperiodic CSI-RS transmission, and the DCI may include the index of TRP3 508. The CSI-RS may be triggered to be sent on TRP3 508. The WTRU may decide to activate the WTRU's panel and receive set 1 of CSI-RS when approaching TRP3 508. The WTRU may also be configured with a set of TRPs from which the TRP may send aperiodic CSI-RS. The trigger message may include a list of TRPs that may be activated. The WTRU may decide that it can receive multiple aperiodic CSI-RS without the need for individual trigger messages from each TRP when moving through various TRPs.

[0150] The WTRU may be triggered to send CSI reports on a TRP different from the TRP that is the source of the CSI-RS resource. The WTRU may determine the TRP on which to send the CSI report 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 on which the WTRU can send reports. If the WTRU decides that it should be served by a TRP not within the valid set, the WTRU may omit sending the CSI report. Similarly, the WTRU may be triggered to send SRS resources to a TRP different from the TRP sending the trigger signal. The TRP index may be included with the trigger signal. The WTRU may determine which panel and which SRS resources to send and when based on the TRP index included in the trigger signal.

[0151] In embodiments, efficient reference signal transmission can be used. In NR, to assist the WTRU in tracking the frequency and timing of the gNB, the WTRU can be configured to receive tracking reference signals. Optionally, the RRC-connected WTRU can receive a higher layer WTRU-specific configuration of the NZP-CSI-RS ResourceSet configured by the higher layer parameter trs-Info. Depending on the location of the WTRU relative to the transmission point, the WTRU can experience different levels of Doppler shift. A fast WTRU can experience the fastest rate of change of Doppler shift when the WTRU is relatively close to the transmission point. Since higher Doppler shifts may require higher speed TRS transmissions, the WTRU can be configured to receive and process TRS at variable transmission speeds.

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

[0153] The WTRU can always be configured to operate with either a lower or higher TRS transmission periodicity and then optionally be signaled to operate in other modes.

[0154] In some embodiments, the TRS pattern may be dynamically indicated. The WTRU may be composed of two or more TRS configurations, each configuration having a temporally preconfigured TRS density. The WTRU may dynamically indicate, for example, DCI or MAC CE to alternate between 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 that used for 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, the WTRU may be composed of two or more TRS configurations, each of which may have a similar TRS density over time but each of which may have a different time offset. Optionally, the WTRU can be indicated to expect one or more TRS transmissions.

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

[0157] In some embodiments, the WTRU may be configured with a TRS pattern having a higher density in the middle of the pattern. In some embodiments, the WTRU may anticipate resetting or resuming a TRS frame when a measurement on the serving TRP, e.g., RSRP, reaches a threshold. Alternatively or additionally, the WTRU may anticipate resetting or resuming a TRS frame after a measurement on the serving TRP falls within a preconfigured range relative to a second TRP, e.g., when RSRP1 is within x dB of RSRP2 and x is a configurable value. In some embodiments, the WTRU may be able to reset or resume a TRS frame based on the geographical location of the WTRU.

[0158] In some embodiments, a TRS triggering mechanism may be used. For example, triggering TRS transmission or TRS transmission with a higher density may be based on a decision by the WTRU or gNB. In WTRU-based embodiments, the WTRU may be able to request the start of TRS transmission or request TRS transmission with a higher density based on several criteria. For example, the WTRU may perform downlink measurements such as RSRP, CQI, Doppler, etc. Alternatively or additionally, the WTRU may be able to proceed with such a request based on the determined location of the WTRU.

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

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

[0161] In some embodiments, a WTRU can receive specific identification and configuration to be the designated WTRU and can represent other WTRUs in the train. The WTRU can receive a configuration to become semi-static or dynamic as the designated WTRU. The WTRU can be configured to act as the designated WTRU only in specific slots, radio frames, etc. The designated WTRU can be assigned a specific RNTI and other dedicated configurations, such as SRS, PUCCH, PUSCH, and SR configurations. The eNB can indicate the designated WTRU based on whether the designated WTRU is transmitting data beyond its priority, whether the WTRU has a high battery power, etc.

[0162] In some embodiments, assuming the existence of sidelink operation similar to operation in V2V communication, the designated WTRU can help the network update the positioning information of other WTRUs near the WTRU.

[0163] In some embodiments, a WTRU may support an aperiodic TRS and / or a semi-persistent TRS that may be associated with a 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 including trs-Info, CSI-RS resource for tracking, and / or CSI-RS for tracking. In some embodiments, the association between an aperiodic TRS and a periodic TRS may be based on one or more of RRC signaling, one or more MAC CE, one or more DCI, and / or any logical equivalent of the foregoing signaling.

[0164] In some embodiments, a WTRU may be composed of an aperiodic TRS, a periodic TRS, and an association between the aperiodic TRS and the periodic TRS via RRC signaling. The association may be based on a TRS resource set ID and / or a QCL type. For example, the periodic TRS resource set configuration may include an associated aperiodic TRS resource set ID. One or more QCL types of the aperiodic TRS, such as 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 composed of an aperiodic TRS and a periodic TRS (e.g., via RRC). Based on the configuration, the WTRU may receive an association between the aperiodic TRS and the periodic TRS (e.g., via MAC CE). 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 indicator, 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, via MAC CE, a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated SSB ID. Based on the indicated SSB ID, the WTRU may determine the associated TRS resource set (e.g., the periodic TRS resource set associated with the indicated SSB).

[0166] In some embodiments, the WTRU may be composed of an aperiodic TRS and a periodic TRS (e.g., via RRC). Based on the configuration, the WTRU may receive an association between the aperiodic TRS and the periodic TRS (e.g., via DCI). 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, the aperiodic TRS trigger configuration may include (e.g., via RRC) one or more pairs of an aperiodic TRS resource set to be triggered and an associated periodic TRS resource set. When the WTRU receives an aperiodic TRS trigger with an aperiodic TRS trigger configuration, the WTRU may receive the associated periodic TRS resource set and the associated aperiodic TRS resource set. In some embodiments, for example, the WTRU may receive, via DCI, 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 indicator, the WTRU may determine the association between the periodic TRS resource set and the associated aperiodic TRS resource set. In some embodiments, for example, the WTRU may receive, via DCI, 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 embodiments, for example, the WTRU may receive, via DCI, a target TRS resource set ID (e.g., an aperiodic TRS resource set ID) and an associated SSB ID. Based on the indicated SSB ID, the WTRU may determine the associated TRS resource set (e.g., the 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 can be provided by RRC signaling, MAC - CE, or the logical equivalent of DCI.

[0168] In some embodiments, the WTRU can request one or more preferred parameters for an aperiodic TRS resource set and / or aperiodic TRS transmission to the gNB. The request (e.g., via one or more of PUCCH, PUSCH, and MAC CE) can be based on one or more of an explicit value indicator or a value indicator based on a configured / pre - defined candidate.

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

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

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

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

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

[0174] In embodiments where the WTRU requests aperiodic TRS transmissions based on Doppler measurements, the WTRU can 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 can receive an aperiodic TRS resource set. For example, if one or more of the reported values are greater than a threshold, the WTRU can receive an aperiodic TRS resource set (the gNB can transmit an aperiodic TRS resource set). In some cases, if one or more of the reported values are less than (or equal to) the threshold, the WTRU may not be able to receive an aperiodic TRS resource set (the gNB may not be able to transmit an aperiodic TRS resource set). The WTRU can indicate a resource set index (e.g., a TRS resource set ID) for measurement to the gNB.

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

[0176] TRS and SRS can be estimated, measured, determined, and / or reported aperiodically. In some embodiments, the WTRU can 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, the Doppler frequency can be used interchangeably with the frequency offset. One or more of the following situations can apply. For example, the Doppler frequency related information can be at least one of a Doppler frequency value (e.g., a frequency offset value), a Doppler frequency rate of change (Δ DF ), or a sign of the Doppler frequency (e.g., positive or negative). The Doppler frequency rate of change can be determined based on one or more of the following parameters. For example, the Doppler frequency rate can be represented as Δ DF =(Δ F1 -Δ F2 ) / Δ T . In the formula, Δ F1 can be the first Doppler frequency at T 1 , Δ F2 can be the second Doppler frequency at T 2 , Δ T can be the time gap between T 1 and T 2 (e.g., Δ T =T 2 -T 1) may also be.

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

[0178] The WTRU may be configured, arranged, or determined to periodically estimate the Doppler frequency change rate, and the periodicity of the estimation of the Doppler frequency change rate may be determined based on one or more of the configuration, the location of the WTRU, or the speed of the WTRU. For example, a WTRU in a first geographical location (e.g., a first zone) can estimate the Doppler frequency change rate with a first periodicity, and a WTRU in a second geographical location (e.g., a second zone) can estimate the Doppler frequency change rate with a second periodicity. The periodicity may be shorter for a WTRU in a geographical location close to the boundary of two TRPs. In another embodiment, a WTRU with a first speed can estimate the Doppler frequency change rate with a first periodicity, and a WTRU with a second speed can estimate the Doppler frequency change rate with a second periodicity.

[0179] The 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 can send Doppler frequency change related information within the configured uplink resources when one or more of the predefined conditions are met. In another way, 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 requests 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 of 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 SRS within 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 is changing, or the Doppler frequency value is higher than a threshold.

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

[0183] Figure 6 depicts an example of a TRP-based frequency offset pre-compensation method 600. Figure 6 shows a WTRU 602, and two TRPs including a first TRP 604 and a second TRP 606. The WTRU 602 can 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 can determine a TRP for transmission and report that determination based on the transmission of an uplink signal (e.g., SRS, PRACH, etc.) and / or an uplink channel (e.g., PUCCH) within 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 can transmit an uplink signal and / or an uplink channel 612 within a 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 can transmit an uplink signal and / or an uplink channel 614 within a second uplink resource associated with the second TRP 606. Based on the transmission, the WTRU and the gNB can determine a frequency offset for pre-compensation and send / receive PDCCH and / or PDSCH 616 - 618 between the determined TRP selected from the first TRP 604 or the second TRP 606.

[0184] The determination of the TRP can be based on, for example, WTRU measurements. For example, the WTRU can measure one or more values of parameters based on a TRS resource set. Based on the measurements, the WTRU can determine a TRS resource set for the TRP determination. One or more of the following rules may apply. In some embodiments, if one or more measured values of the TRS resource set are greater than a threshold, the WTRU can determine the TRS resource set. If one or more measured values are less than (or equal to) the threshold, the WTRU cannot determine the TRS resource set. In some embodiments, the WTRU can compare one or more measured values from multiple TRS resource sets. Based on the measurements, the WTRU can determine the TRS resource set that provides the maximum (or minimum) 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 with a shorter distance from the WTRU or a lower path loss can be determined. With respect to zone, for example, a TRS resource set associated with the zone in which the WTRU is located can be determined. With respect to BRS, for example, the TRS resource set can be determined based on the measurement of the associated BRS resource / resource set. The BRS may be one or more of a CSI-RS resource / resource set, or CSI-RS and SSB for a beam management resource / resource set.

[0186] The association between the TRS resource set and the uplink signal and / or uplink channel may be based on one or more of the gNB configuration, metrics, or predefined relationships. In some embodiments, the WTRU may be able to receive the configuration and / or metrics for the association. The association may be configured or indicated based on one or more of the following: TRS resource set ID, SRS resource / resource set ID, CORESET / SS group, upper layer (e.g., MAC, RLC, PDCP, or SDAP layer) index, TRP ID, PUCCH resource ID, PRACH resource ID, or associated TCI state ID or TCI state group ID. The configuration / metrics may be sent or received using one or more of the following: RRC message, MAC CE, DCI (WTRU-specific DCI and / or group DCI), or 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: cell ID associated with the TRS resource set, TRS resource set ID associated with the TRS resource set, SSB ID associated with the TRS resource set, TRP ID associated with the TRS resource set, or configured parameters of the TRS resource set (e.g., periodicity, density, burst, time offset, or frequency offset).

[0188] Figure 7 is an example of M-TRP SFN transmission 700 with Doppler compensation. In this example, for cell n702, four TRPs 706 - 712 are arranged along track 714 on which train 716 can run. In M-TRP SFN deployment where M TRPs jointly transmit to a WTRU, the WTRU may experience different Doppler shifts from each TRP. These Doppler shifts are shown as Δf1 704a from TRP2 708 and Δf1 704b from TRP3 710. When Doppler compensation is performed by the TRPs, for proper operation of the M-TRP SFN, at least M - 1 TRPs can perform Doppler shift pre-compensation so that the received carrier frequencies match at the WTRU. An indication of whether a TRP can or cannot perform Doppler pre-compensation can be provided dynamically.

[0189] In some embodiments, the TRPs for performing Doppler pre-compensation can be selected based on the geographical location or area of the WTRU. For this purpose, the network can configure the WTRU having a particular SRS resource set based on the geographical location of the WTRU or the area to which the WTRU belongs. The selection of SRS by the WTRU may indicate the geographical location / area of the WTRU to the network.

[0190] In some embodiments, the TRP for performing Doppler pre - compensation can 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 can be used. For example, the RSRP or RSRQ from each TRP can be tested against or compared to a specific threshold. The selection of the TRP for performing Doppler pre - compensation can be done by the network based on the reported RSRP, CQI, or RSRQ measurements sent from the WTRU to the network. In some embodiments, the selection of the TRP is done at the WTRU and can be indicated to the network by transmitting an SRS selected from a pre - configured set of SRSs. The selection of the SRS / SRS resource set by the WTRU can indicate the TRP for performing Doppler pre - compensation.

[0191] In some embodiments, to indicate which TRP should perform Doppler pre - compensation, the network can use downlink signaling to request an aperiodic or semi - persistent SRS transmission from the WTRU. For example, if two or more TRPs implement an SFN, the TRP for performing or not performing Doppler pre - compensation can be indicated by the WTRU transmitting an SRS from a pre - configured set of SRSs to a specific TRP. In this way, the WTRU can be composed of two different sets of SRS resources, with an association between each SRS resource and a TRP. For example, the WTRU can be composed of a first set and a second set of SRS resources associated with a first TRP and a second TRP, respectively. When the WTRU uses the first SRS resource, the WTRU indicates a preference for pre - compensation by the first TRP. When the WTRU uses the second SRS resource, the WTRU indicates a preference for pre - compensation by 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 spacings. The WTRU may determine an SRS resource within the set based on measurement results obtained from at least one measurement resource. For example, the measurement results may consist of, or may be composed of, an estimate of the time variation (or Doppler spread) of a channel from a reference signal such as a TRS or PT-RS. Alternatively or additionally, the WTRU may determine the SRS resource based on an estimate of the WTRU speed from positioning information. For example, the WTRU may select a first SRS resource if the Doppler estimate (or WTRU speed) is below a threshold and may select a second SRS resource if the Doppler estimate (or WTRU speed) is above the threshold. The threshold and the measurement resource may be configured by a higher layer for the set of possible SRS resources. The WTRU may report, for example, the estimated Doppler, WTRU speed, or the selected SRS resource in a measurement report. Such embodiments may help the network receive resources adapted to estimate the necessary Doppler pre-compensation.

[0193] The SSB configuration can be used for two-way transmission. The SSB can generally be considered as the basis for the WTRU to perform cell / beam detection and measurement. Thus, the periodicity of the SSB can be linked to the reading of the cell's MIB. For example, for mobility as CSI-RS, there may be other RS signals configured for each WTRU or for a set of WTRUs. These RS may not necessarily be linked to cell detection.

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

[0195] In some cases, the WTRU may always have an anchor TRP, and the Doppler effect is effectively evaluated and corrected. The WTRU can be indicated via a specific SRS, for example, where the TRP is the anchor. Thus, the TRPs providing other services can pre-compensate or adjust the PDSCH and related DM-RS. Some RS signals may need to be pre-compensated, while other RS signals may not need to be pre-compensated from non-anchor TRPs.

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

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

[0198] The SRS resources are divided per SSB range and can be configured accordingly by the gNB, so that the gNB can accurately identify which TRP the WTRU uses as the anchor TRP reference and which TRPs are non-anchor TRPs.

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

[0200] Under these embodiments, dynamic reservation may enable load balancing and WTRU measurement optimization. Similarly, the TCI state, which includes information regarding the SSB of the beam, may indicate the same assumptions for the entire defined range of the SSB index.

[0201] Some embodiments may involve signaling the beam direction opposite to the SSB. An auxiliary indicator / split of the SSB index range (formed in any of the above cases, SIB, semi-statically or dynamically configured RRC) may be done by indicating the opposite beam direction via a direction bit. This signaled direction bit may serve to subgroup the WTRU beam range under certain similar QCL assumptions where different direction bits are QCL discriminators. This beam direction discriminator may be extended to subgrouping of the SRS index to enable the WTRU to be correctly used to serve the TRP under a specific beam range and / or direction.

[0202] The reduced step acquisition mode may be input by the WTRU. Since the HST WTRU may camp on the same cell over a long period of time, there may be no change in the cell ID, and it may not be necessary to continuously perform all steps related to PSS / SSS and PBCH detection. Therefore, the WTRU may enter a reduced step acquisition (RSA) mode in which at least some of the functions related to SSB detection and decoding processing may be omitted.

[0203] In some embodiments, the WTRU may be able to operate in the RSA mode based on one or more of the following conditions. For example, the WTRU may be configured by an RRC configuration, or another logically equivalent signal, to operate in the RSA mode. The WTRU may enter the RSA mode based on an implicit or explicit indicator within the received IE by an L1 / L2 command. The WTRU may enter the RSA mode based on an implicit indicator via a determination of the usage of downlink resources, such as detection of the usage of a specific CSI-RS configuration or TRS. The WTRU may enter the RSA mode based on measurement values, such as Doppler shift, Doppler spread, RSRP, SINR, positioning, etc. The WTRU may enter the RSA mode based on a determination that pre-compensation is not applied to the SSB.

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

[0205] The WTRU can be composed of 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 can receive RSA-PDSCH transmissions periodically or, alternatively, the WTRU can expect to receive RSA-PDSCH transmissions when triggered by the WTRU. The configured RSA-PDSCH resources can also include some resources for carrying some reference signals for timing / frequency tracking.

[0206] A downlink transmission scheme for supporting PDCCH transmissions can be used in the SFN expansion.

[0207] Some embodiments may enable multi-port PDCCH DM-RS. In order 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, the current design of PDCCH DM-RS can only enable one DM-RS port. One or a combination of the following approaches can be used to enable multiple DM-RS ports, as a result of which the WTRU can perform accurate channel estimation considering 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 over one or two PRBs in the frequency domain and one slot in the time domain. When time-frequency resources for non-zero power DM-RS are configured for a TRP, the WTRU can receive a scaled version of the PDCCH DM-RS from the TRP. When 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 indicator can be based on, for example, RRC signaling (or another logically equivalent signal), on which TRS is used for carrier frequency estimation, on the TRP ID, or on any combination thereof.

[0210] The WTRU can perform DM-RS estimation considering the orthogonal cover code (OCC) used by each TRP when the PDCCH duration is two OFDM symbols as shown in FIG. 11. When the PDCCH duration is three OFDM symbols, the WTRU can use a virtual orthogonal OCC to distinguish between radio signals received from two TRPs. Alternatively, the WTRU can receive DM-RS having different OCCs applicable to the two-symbol duration from both TRPs. Further, the WTRU can receive one additional DM-RS on a third OFDM symbol transmitted by one particular TRP.

[0211] The WTRU can perform DM-RS estimation based on the orthogonal / virtual orthogonal DM-RS signal sequences received from each TRP. For this purpose, for each TRP, a virtual random sequence generator can be uniquely initialized. For example, in an implementation example of the SFN, when two TRPs transmit PDCCH, the PN sequence generation can be initialized as follows.

Number

Number

[0212] FIG. 8 shows zero-power and non-zero-power demodulation reference signal (DM-RS) configurations 800, 820 for physical downlink control channel (PDCCH) transmission having a single orthogonal frequency division multiplexing (OFDM) symbol duration. In an exemplary configuration 800 of a first TRP, the zero-power DM-RS symbols 802-806 and the non-zero-power symbols 808-812 can be alternating in the frequency domain 814 and occupy only the first symbol in the time domain 816.

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

[0214] FIG. 9 shows first zero power and non-zero power DM-RS configurations 900, 920 for PDCCH transmission having a 2 OFDM symbol duration. In an exemplary configuration 900 of the first TRP, non-zero power DM-RS symbols 902 to 906 may precede zero power DM-RS symbols 908 to 912 within a time domain 916, while occupying the same resources within a frequency domain 914.

[0215] In an exemplary configuration 920 of the second TRP, zero power DM-RS symbols 922 to 926 may precede non-zero power DM-RS symbols 928 to 932 within a time domain 936, while occupying the same resources within a frequency domain 934.

[0216] FIG. 10 shows second zero power and non-zero power DM-RS configurations 1000, 1020 for PDCCH transmission having a 2 OFDM symbol duration. In an exemplary configuration 1000 of the first TRP, non-zero power DM-RS symbols 1002 to 1006 alternate with zero power DM-RS symbols 1008 to 1012 within a time domain 1016 and may occupy the same frequency resources within a frequency domain 1014.

[0217] In an exemplary configuration 1020 of the second TRP, zero power DM-RS symbols 1022 to 1026 may alternate with non-zero power DM-RS symbols 1028 to 1032 within a time domain 1036, while occupying the same resources within a frequency domain 1034.

[0218] Figure 11 shows the first zero-power and non-zero-power DM-RS configurations 1110 and 1130 for PDCCH transmission with a 3 OFDM symbol duration. In the first TRP example 1110, the non-zero-power DM-RS 1102 to 1112 are placed before and after the zero-power DM-RS symbols 1114 to 1118 within time 1122. The non-zero-power DM-RS may or may not be placed at the same location in the frequency domain 1120 as the zero-power DM-RS.

[0219] For the configuration 1130 of the second TRP, the zero-power DM-RS 1132 to 1142 can be used together with the non-zero-power DM-RS symbols 1146 to 1148 located between the zero-power DM-RS symbols 1132 to 1142 within time 1152. The non-zero-power DM-RS symbols 1146 to 1148 may or may not be placed at the same location in the frequency domain 1150 as the zero-power DM-RS 1132 to 1142.

[0220] Figure 12 is an explanation of the second zero-power and non-zero-power DM-RS configurations 1200 and 1250 for PDCCH transmission having a 3 OFDM symbol duration configuration. In the exemplary configuration 1200, the zero-power DM-RS symbols 1202 to 1218 and the non-zero-power DM-RS 1220 to 1236 can be alternating within the time domain 1240 and within the frequency domain 1238. In the exemplary configuration 1250, the non-zero-power DM-RS 1250 - 1268 and the zero-power DM-RS symbols 1270 to 1286 can be alternating within the time domain 1290 and within the frequency domain 1288.

[0221] FIG. 13 illustrates orthogonal cover code (OCC)-based DM-RS configurations 1300 and 1320 for PDCCH transmission having a 2 OFDM symbol duration. In configuration 1300, DM-RS 1302 to 1312 having an OCC k spreading over two OFDM symbols in time domain 1316 are shown. The DM-RS may be located within the same resource in frequency domain 1314. In configuration 1320, DM-RS 1322 to 1332 having an OCC j spreading over two OFDM symbols in time domain 1336 are shown. The DM-RS may be located within the same resource in frequency domain 1334.

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

[0223] Multiple TCI states may be activated for PDCCH reception. For receiving PDCCH transmission in an example implementation of SFN, two TCI states can be activated for a CORESET. For this purpose, the indicator of the TCI state can be extended to define two TCI states (one TCI state for each TRP) for the same code point. The WTRU can determine the QCL relationship between the RS and the PDCCH DM-RS from each TRP based on the activated TCI state.

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

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

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

[0227] In some approaches, the WTRU can determine the HST-SFN transmission mode based on the TCI / QCL relationship between the PDSCH DM-RS and the TRS. For example, if each TRS is used as the source RS of the TCI state and the PDSCH DM-RS is QCLed with the TRS in types A and D, the WTRU can determine that the HST-SFN downlink transmission mode 2 is enabled.

[0228] The features and elements are described above in specific combinations, but one of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Further, the methods described herein can be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, magnetic media such as read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer can be implemented using a processor associated with software.

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), the configuration information indicating, for each respective zone id of the one or more zone ids, a beam reference signal (BRS) and uplink resources, and indicating, for each respective zone id of the one or more zone ids, one or more of a set of transmission configuration indicator (TCI) states, a search space, or a control resource set (CORESET) configuration; and transmitting to a base station, using uplink resources associated with a zone id, an indication of a zone id determined from the one or more zone ids based on measurements of one or more BRSs indicated via the configuration information.

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), the configuration information indicating, for each respective zone id of the one or more zone ids, a beam reference signal (BRS), a search space, and uplink resources, and indicating, for each respective zone id of the one or more zone ids, one or more of a set of transmission configuration indicator (TCI) states or a control resource set (CORESET) configuration; determining a zone id of the one or more zone ids based on measurements of one or more BRSs indicated via the configuration information; monitoring a search space for a physical downlink control channel (PDCCH) transmission according to a search space configuration for the determined zone id; 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 a zone id to a base station using uplink resources configured for said 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 associated with one or more zones having one or more zone identifiers (zone ids), the configuration information indicating, for each respective zone id of the one or more zone ids, a beam reference signal (BRS) and uplink resources, and indicating, for each respective zone id of the one or more zone ids, one or more of a set of transmission configuration indicator (TCI) states, a search space, or a control resource set (CORESET) configuration; and circuitry configured to indicate to a base station a zone id determined from the one or more zone ids based on measurements of one or more BRSs indicated via the configuration information 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 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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