TW202033011A - Methods and procedures for iab and v2x - Google Patents

Abstract

Methods and apparatus for integrated access and backhaul (IAB) and vehicle-to-everything (V2X) systems are disclosed herein. A first wireless transmit/receive unit (WTRU) may monitor, in a first time slot, a first frequency resource comprising a first plurality of resource blocks (RBs) and having a first frequency range, for signals from a second WTRU. The first frequency resource may be associated with a physical sidelink shared channel (PSSCH) of the second WTRU. The WTRU may determine a feedback frequency resource based on at least one of the first frequency range, a number of RBs in the first plurality of RBs, or an identity of the first WTRU. The WTRU may transmit, in a second time slot, to the second WTRU, feedback information using the feedback frequency resource.

Description

IAB and V2X methods and procedures

Cross references to related applications

This application claims the rights and interests of U.S. Provisional Patent Application No. 62/767,291 filed on November 14, 2018 and U.S. Provisional Patent Application No. 62/790,303 filed on January 9, 2019, the contents of which are incorporated by reference Be incorporated into this article.

The recent 3rd Generation Partnership Project (3GPP) standards discussion defined several deployment scenarios, such as indoor hotspots, dense cities, rural areas, urban macros, and high speeds. Based on the general requirements of the International Telecommunication Union Radio Communications Department (ITU-R), Next Generation Mobile Network (NGMN) and 3GPP, the use cases of emerging 5G systems can be broadly classified as enhanced mobile broadband (eMBB) and large-scale machines Type communication (mMTC) and ultra-reliable and low-latency communication (URLLC). These use cases focus on meeting different performance requirements, such as higher data rates, higher spectral efficiency, low power and higher energy efficiency, and/or lower latency and higher reliability. In addition, for various deployment scenarios, consider a wide range of spectral bands ranging from 700 MHz to 80 GHz. For various reasons (including mmW spectrum usage and local deployment of massive MIMO or multi-beam systems), new radio (NR) systems are expected to have a larger available bandwidth compared to Long Term Evolution (LTE) systems.

This article discloses methods and devices for integrated access and backhaul (IAB) and Internet of Vehicles (V2X) systems. The first wireless transmission/reception unit (WTRU) may monitor a first frequency resource including a first plurality of resource blocks (RB) and having a first frequency range in a first time slot for a signal from a second WTRU. The first frequency resource may be associated with the physical side link shared channel (PSSCH) of the second WTRU. The WTRU may determine the feedback frequency resource based on at least one of the first frequency range, the number of RBs in the first plurality of RBs, or the identification code of the first WTRU. The WTRU may use the feedback frequency resource in the second time slot to transmit feedback information to the second WTRU.

Figure 1A is a diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments can be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, message transmission, and broadcast for multiple wireless users. The communication system 100 can enable multiple wireless users to access such content by sharing system resources including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA) ), single carrier FDMA (SC-FDMA), zero-tail unique word discrete Fourier transform extended OFDM (ZT-UW-DTS-S-OFDM), unique word OFDM (UW-OFDM), resource block filtering OFDM, and multiple filter banks Carrier (FBMC) and so on.

As shown in FIG. 1A, the communication system 100 may include wireless transmission/reception units (WTRU) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, and a public switched telephone network. (PSTN) 108, Internet 110, and other networks 112. However, it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. For example, the WTRU 102a, 102b, 102c, 102d (any of which may be referred to as a station (STA)) may be configured to transmit and/or receive wireless signals, and may include user equipment (UE), mobile Stations, fixed or mobile subscriber units, subscription-based units, pagers, mobile phones, personal digital assistants (PDAs), smart phones, laptop computers, small laptops, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMD), vehicles, drones, medical devices and applications (such as remote surgery), industrial devices and applications (such as robots and /Or other wireless devices operating in an industrial and/or automatic processing chain environment), consumer electronic devices, and devices operating on commercial and/or industrial wireless networks, etc. Any one of the WTRU 102a, 102b, 102c, 102d may be referred to interchangeably as a UE.

The communication system 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks (e.g., CN 106, Internet Any type of device on the network 110, and/or other networks 112). For example, the base stations 114a and 114b may be base transceiver stations (BTS), Node B, eNodeB (eNB), local Node B, local eNodeB, next-generation Node B such as gNodeB (gNB), new radio (NR) Node B, website controller, access point (AP), and wireless router, etc. Although each of the base stations 114a, 114b is described as a single element, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

The base station 114a may be part of the RAN 104, and the RAN may also include other base stations and/or network elements (not shown), such as base station controller (BSC), radio network controller (RNC), relay Nodes and so on. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies called cells (not shown). These frequencies can be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. Cells can provide wireless service coverage for specific geographic areas that are relatively fixed or that may change over time. Cells can be further divided into cell sectors. For example, the cell associated with the base station 114a can be divided into three sectors. Therefore, in an embodiment, the base station 114a may include three transceivers, that is, each transceiver corresponds to a sector of the cell. In an embodiment, the base station 114a may use multiple input multiple output (MIMO) technology, and may use a complex transceiver for each sector of the cell. For example, beamforming can be used to transmit and/or receive signals in a desired spatial direction.

The base stations 114a, 114b can communicate with one or more of the WTRUs 102a, 102b, 102c, 102d via the air interface 116, where the air interface can be any suitable wireless communication link (such as radio frequency (RF), Microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 can be established using any suitable radio access technology (RAT).

More specifically, as described above, the communication system 100 may be a multiple access system, and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and so on. For example, the base station 114a and the WTRU 102a, 102b, 102c in the RAN 104 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use wideband CDMA (WCDMA) To create an air interface 116. WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include high-speed downlink (DL) packet access (HSDPA) and/or high-speed uplink (UL) packet access (HSUPA).

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), where the technologies may use Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced (LTE-A Pro) are used to establish the air interface 116.

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies that can use NR to establish the air interface 116, such as NR radio access.

In an embodiment, the base station 114a and the WTRU 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, and 102c may implement LTE radio access and NR radio access together (for example, using dual connectivity (DC) principles). Therefore, the air interface used by the WTRU 102a, 102b, 102c can be characterized by multiple types of radio access technologies, and/or transmissions sent to/from multiple types of base stations (e.g., eNB and gNB).

In other embodiments, the base station 114a and the WTRUs 102a, 102b, and 102c may implement the following radio technologies, such as IEEE 802.11 (i.e., wireless high-fidelity (WiFi)), IEEE 802.16 (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), for GSM evolution Enhanced data rate (EDGE), and GSM EDGE (GERAN), etc.

The base station 114b in FIG. 1A can be, for example, a wireless router, a local node B, a local eNode B, or an access point, and can use any appropriate RAT to facilitate, for example, business premises, residences, vehicles, campuses, industrial facilities, air corridors (For example for drones) and wireless connections in local areas such as roads. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may use a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or Femtocells. As shown in FIG. 1A, the base station 114b can be directly connected to the Internet 110. Therefore, the base station 114b does not need to access the Internet 110 via the CN 106.

The RAN 104 may communicate with the CN 106, which may be configured to provide voice, data, applications, and/or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d Any type of network. The data may have different quality of service (QoS) requirements, such as different circulation requirements, delay requirements, fault tolerance requirements, reliability requirements, data circulation requirements, and mobility requirements. CN 106 can provide call control, billing services, mobile location-based services, prepaid calling, Internet connection, video distribution, etc., and/or can perform high-level security functions such as user authentication. Although not shown in FIG. 1A, it should be understood that the RAN 104 and/or CN 106 can directly or indirectly communicate with other RANs that use the same RAT or different RATs as the RAN 104. For example, in addition to connecting with the RAN 104 using NR radio technology, the CN 106 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or other networks 112. PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global communication protocol that uses public communication protocols (such as TCP, User Datagram Protocol (UDP) and/or IP in the Transmission Control Protocol/Internet Protocol (TCP/IP) Internet Protocol Family). Connect the computer network device system. The network 112 may include a wired or wireless communication network owned and/or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, where the one or more RANs may use the same RAT as the RAN 104, or a different RAT.

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

FIG. 1B is a system diagram showing an exemplary WTRU 102. As shown in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmission/reception element 122, a speaker/microphone 124, a keypad 126, a display/touch pad 128, a non-removable memory 130, and a removable memory Body 132, power supply 134, global positioning system (GPS) chipset 136 and/or other peripheral devices 138. It should be understood that, while maintaining compliance with the embodiments, the WTRU 102 may also include any sub-combination of the foregoing elements.

The processor 118 may 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 the DSP core, a controller, a microcontroller, Dedicated integrated circuit (ASIC), field programmable gate array (FPGA), any other type of integrated circuit (IC), state machine, etc. The processor 118 may perform signal encoding, data processing, power control, input/output processing, and/or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, and the transceiver 120 may be coupled to the transmission/reception element 122. Although FIG. 1B describes the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may also be integrated in an electronic component or chip together.

The transmission/reception element 122 may be configured to transmit signals to or receive signals from a base station (such as base station 114a) via the air interface 116. For example, in one embodiment, the transmission/reception element 122 may be an antenna configured to transmit and/or receive RF signals. For example, in another embodiment, the transmission/reception element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals. In an embodiment, the transmission/reception element 122 may be configured to transmit and/or receive RF and optical signals. It should be understood that the transmission/reception element 122 may be configured to transmit and/or receive any combination of wireless signals.

Although the transmission/reception element 122 is described as a single element in FIG. 1B, the WTRU 102 may include any number of transmission/reception elements 122. More specifically, the WTRU 102 may use MIMO technology. Therefore, in an embodiment, the WTRU 102 may include two or multiple transmission/reception elements 122 (such as multiple antennas) that transmit and receive wireless signals via the air interface 116.

The transceiver 120 may be configured to modulate the signal to be transmitted by the transmission/reception element 122 and demodulate the signal received by the transmission/reception element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Therefore, the transceiver 120 may include a plurality of transceivers that allow the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

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

The processor 118 may receive power from the power source 134 and may be configured to distribute and/or control power for other elements in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry battery packs (such as nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc. .

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) related to the current location of the WTRU 102. As a supplement or alternative to the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and/or based on information received from two or more nearby base stations. Signal timing to determine its location. It should be understood that, while maintaining compliance with the embodiments, the WTRU 102 may use any appropriate positioning method to obtain location information.

The processor 118 may also be coupled to other peripheral devices 138, where the peripheral devices may include one or more software and/or hardware modules that provide additional features, functions, and/or wired or wireless connections. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and/or video), universal serial bus (USB) ports, vibration devices, TV transceivers, hands-free headsets, Bluetooth ®Modules, FM radio units, digital music players, media players, video game console modules, Internet browsers, virtual reality and/or augmented reality (VR/AR) devices, and activity tracking And so on. The peripheral device 138 may include one or more sensors. The sensor can be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor , Geographical position sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, humidity sensor, etc.

The WTRU 102 may include a full-duplex radio for which some or all of the signals (e.g., associated with specific subframes for UL (e.g. for transmission) and DL (e.g. for reception)) The reception or transmission can be parallel and/or simultaneous. The full-duplex radio device may include signal processing via hardware (e.g. choke coil) or via a processor (e.g. a separate processor (not shown) or via processor 118) to reduce and/or substantially eliminate self The interference management unit for interference. In an embodiment, the WTRU 102 may include half-duplex for transmitting and receiving some or all of the signals (e.g., associated with specific subframes used for UL (e.g., for transmission) or DL (e.g., for reception)) Radio device.

FIG. 1C is a system diagram showing the RAN 104 and the CN 106 according to the embodiment. As described above, the RAN 104 may use E-UTRA radio technology on the air interface 116 to communicate with the WTRUs 102a, 102b, 102c. The RAN 104 can also communicate with the CN 106.

The RAN 104 may include eNodeBs 160a, 160b, 160c, however, it should be understood that the RAN 104 may include any number of eNodeBs while maintaining compliance with the embodiments. Each of the eNodeBs 160a, 160b, 160c may include one or more transceivers that communicate with the WTRU 102a, 102b, 102c via the air interface 116. In one embodiment, the eNodeB 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNodeB 160a may use multiple antennas to transmit wireless signals to and/or receive wireless signals from the WTRU 102a.

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

The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a service gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the aforementioned elements are all described as being part of the CN 106, it should be understood that any of these elements may be owned and/or operated by entities other than the CN operator.

The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface, and may act as a control node. For example, the MME 162 may be responsible for authenticating users of WTRUs 102a, 102b, 102c, performing bearer activation/deactivation, and selecting a specific service gateway during the initial connection of WTRUs 102a, 102b, 102c, and so on. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that use other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each of the eNodeBs 160a, 160b, and 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route user data packets to the WTRU 102a, 102b, 102c and forward user data packets from the WTRU 102a, 102b, 102c. In addition, the SGW 164 can also perform other functions, such as anchoring the user plane during the handover between eNodeBs, triggering paging when DL data is available for WTRUs 102a, 102b, 102c, and managing and storing WTRUs 102a, 102b, 102c context and so on.

The SGW 164 can be connected to the PGW 166. The PGW 166 can provide the WTRU 102a, 102b, 102c with access to a packet switching network (such as the Internet 110) to facilitate communication between the WTRU 102a, 102b, 102c and IP-enabled devices Communication.

CN 106 can facilitate communication with other networks. For example, the CN 106 may 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 may include or communicate with an IP gateway (such as an IP Multimedia Subsystem (IMS) server), and the IP gateway may serve as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, and 102c with access to the other network 112, where the network 112 may include other wired and/or wireless networks owned and/or operated by other service providers.

Although the WTRU is described as a wireless terminal in FIGS. 1A to 1D, it should be conceived that in some typical embodiments, such a terminal and the communication network may use (for example, temporary or permanent) wired communication interfaces.

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

A WLAN adopting an infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP can access or interface to a distributed system (DS), or carry traffic into and/or out of another type of wired/wireless network of the BSS. Traffic from outside the BSS to the STA can arrive via the AP and be delivered to the STA. Traffic originating from the STA and to destinations outside the BSS can be sent to the AP for delivery to their respective destinations. The traffic between the STAs in the BSS can be sent via the AP, for example, when the source STA can send the traffic to the AP, and the AP can deliver the traffic to the destination STA. The traffic between STAs in the BSS can be considered and/or referred to as point-to-point traffic. The point-to-point traffic can be sent between the source and destination STAs (for example, directly in between) using direct link establishment (DLS). In some typical embodiments, DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). For example, a WLAN that uses an independent BSS (IBSS) mode does not have an AP, and STAs (for example, all STAs) within the IBSS or using the IBSS can directly communicate with each other. Here, the IBSS communication mode may sometimes be referred to as an "Ad-hoc" communication mode.

When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel (such as the main channel). The main channel can have a fixed width (for example, a bandwidth of 20 MHz) or a dynamically set width. The main channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some typical embodiments, (for example, in an 802.11 system), Carrier Sense Multiple Access (CSMA/CA) with collision avoidance can be implemented. For CSMA/CA, STAs including APs (for example, each STA) can sense the main channel. If a specific STA senses/detects and/or determines that the main channel is busy, then the specific STA can fall back. In a designated BSS, one STA (for example, only one station) can transmit at any designated time.

High throughput (HT) STAs can use 40 MHz wide channels to communicate (for example, by combining 20 MHz wide main channels with 20 MHz wide adjacent or non-adjacent channels to form 40 MHz wide channels) .

Very high throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz and/or 160 MHz wide channels. 40 MHz and/or 80 MHz channels can be formed by combining consecutive 20 MHz channels. The 160 MHz channel can be formed by combining 8 continuous 20 MHz channels or by combining two discontinuous 80 MHz channels (this combination can be called an 80+80 configuration). For the 80+80 configuration, after channel encoding, the data can be passed and passed through a segmented parser, which can split the data into two streams. On each stream, inverse fast Fourier transform (IFFT) processing and time domain processing can be performed separately. The stream can be mapped on two 80 MHz channels, and the data can be transmitted by a transmitting STA. On the receiver of a receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the media access control (MAC).

802.11af and 802.11ah support operation modes below 1 GHz. Compared with the channel operating bandwidth and carrier in 802.11n and 802.11ac, the channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to typical embodiments, 802.11ah can support meter type control/machine type communication (MTC) (for example, MTC devices in the macro coverage area). The MTC device may have certain capabilities, for example, including a limited ability to support (e.g., only support) certain and/or limited bandwidth. The MTC device may include a battery, and the battery life of the battery is higher than a critical value (for example, to maintain a long battery life).

WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The bandwidth of the main channel may be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the main channel may be set and/or restricted by all STAs operating in the BSS supporting the minimum bandwidth operation mode. In the 802.11ah example, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operation modes, for STAs that support (for example, only support) 1 MHz mode (For example, MTC type device), the main channel can be 1 MHz wide. Carrier sensing and/or network allocation vector (NAV) settings may depend on the status of the main channel. If the main channel is busy (for example, because the STA (which only supports 1 MHz operation mode) is transmitting to the AP), then even if most of the available frequency bands remain free and available for use, all available frequency bands can be considered busy.

In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. According to the country code, the total bandwidth available for 802.11ah is from 6 MHz to 26 MHz.

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

The RAN 104 may include gNB 180a, 180b, 180c, but it should be understood that the RAN 104 may include any number of gNBs while maintaining compliance with the embodiments. Each of the gNB 180a, 180b, 180c may include one or more transceivers to communicate with the WTRU 102a, 102b, 102c via the air interface 116. In one embodiment, gNB 180a, 180b, 180c can implement MIMO technology. For example, gNB 180a, 180b may use beamforming to transmit and/or receive signals to and/or from gNB 180a, 180b, 180c. Thus, for example, gNB 180a may use multiple antennas to transmit wireless signals to and receive wireless signals from WTRU 102a. In the embodiment, the gNB 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit complex component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on the unlicensed spectrum, while the remaining component carriers can be on the licensed spectrum. In an embodiment, the gNB 180a, 180b, and 180c may implement coordinated multipoint (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

The WTRU 102a, 102b, 102c may use transmissions associated with a scalable parameter set (numweology) to communicate with gNB 180a, 180b, 180c. For example, for different transmissions, different cells and/or different parts of the wireless transmission spectrum, the OFDM symbol spacing and/or OFDM subcarrier spacing may be different. The WTRU 102a, 102b, 102c may use sub-frames or transmission time intervals (TTIs) with different or scalable lengths (e.g., containing a different number of OFDM symbols and/or lasting different absolute time lengths) to compare with the gNB 180a, 180b , 180c to communicate.

The gNB 180a, 180b, 180c may be configured to communicate with WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In a standalone configuration, the WTRU 102a, 102b, 102c can communicate with the gNB 180a, 180b, 180c without accessing other RANs (e.g., eNodeB 160a, 160b, 160c). In a standalone configuration, the WTRU 102a, 102b, 102c may use one or more of the gNB 180a, 180b, 180c as the action anchor. In a standalone configuration, the WTRU 102a, 102b, 102c may use signals in the unlicensed frequency band to communicate with the gNB 180a, 180b, 180c. In a non-standalone configuration, the WTRU 102a, 102b, 102c may communicate/connect with the gNB 180a, 180b, 180c while communicating/connecting with another RAN (e.g., eNodeB 160a, 160b, 160c). For example, the WTRU 102a, 102b, 102c may implement the DC principle while communicating with one or more gNB 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-independent configuration, the eNodeB 160a, 160b, 160c can act as the anchor point of the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c can provide additional coverage and/or liquidity to serve the WTRU 102a, 102b, 102c.

Each of gNB 180a, 180b, and 180c can be associated with a specific cell (not shown), and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and/or DL, and support networks Cut, DC, implement intercommunication between NR and E-UTRA, route user plane data to user plane functions (UPF) 184a, 184b, and route control plane information to access and mobility management function (AMF) 182a , 182b and so on. As shown in FIG. 1D, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

The 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 possibly data network (DN) 185a, 185b. Although the aforementioned elements are all described as part of the CN 106, it should be understood that any of these elements can be owned and/or operated by entities other than the CN operator.

The AMF 182a, 182b may be connected to one or more of the gNB 180a, 180b, 180c in the RAN 104 via the N2 interface, and may act as a control node. For example, AMF 182a, 182b may be responsible for authenticating users of WTRU 102a, 102b, 102c, supporting network interception (for example, processing different protocol data unit (PDU) conversations with different requirements), selecting specific SMF 183a, 183b, and managing Registration area, termination of non-access stratum (NAS) messaging, and mobility management, etc. The AMF 182a, 182b may use network slicing to customize the CN support provided to the WTRU 102a, 102b, 102c based on the type of service used by the WTRU 102a, 102b, 102c. For example, different network interceptions can be established for different use cases, such as services that rely on ultra-reliable low-latency (URLLC) access, services that rely on enhanced large-scale mobile broadband (eMBB) access, and/ Or services for MTC access and so on. AMF 182a, 182b can be provided for use in RAN 104 and other RANs (not shown) that use other radio technologies (for example, LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi) Control plane function for switching between.

SMF 183a, 183b can be connected to AMF 182a, 182b in CN 106 via N11 interface. The SMF 183a, 183b can also be connected to the UPF 184a, 184b in the CN 106 via the N4 interface. SMF 183a, 183b can select and control UPF 184a, 184b, and can configure traffic routing via UPF 184a, 184b. SMF 183a, 183b can perform other functions, such as management and allocation of UE IP address, management of PDU dialogue, control strategy implementation and QoS, and provision of DL data notification, etc. The PDU dialog type can be IP-based, non-IP-based, Ethernet-based, and so on.

UPF 184a, 184b can be connected to one or more of gNB 180a, 180b, 180c in RAN 104 via N3 interface, which can provide packet-switching network for WTRU 102a, 102b, 102c (such as Internet 110) To facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices, UPF 184, 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU dialogue, Handle user plane QoS, cache DL packets, and provide mobility anchoring, etc.

CN 106 can facilitate communication with other networks. For example, CN 106 may include an IP gateway (such as an IP Multimedia Subsystem (IMS) server) serving as an interface between CN 106 and PSTN 108, or may communicate with the IP gateway. In addition, the CN 106 may provide the WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and/or wireless networks owned and/or operated by other service providers. In one embodiment, the WTRU 102a, 102b, 102c can be connected via the N3 interface with UPF 184a, 184b, and the N6 interface between UPF 184a, 184b and DN 185a, 185b and connected via UPF 184a, 184b To the local data network (DN) 185a, 185b.

In view of the corresponding descriptions of FIGS. 1A to 1D and FIGS. 1A to 1D, one or more or all of the functions described herein with reference to one or more of the following can be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN185 ab and/ Or one or more of any other devices described here. These simulation devices may be one or more devices configured to simulate one or more or all of the functions described herein. For example, these simulation devices can be used to test other devices and/or to simulate network and/or WTRU functions.

The simulation device can be designed to perform one or more tests of other devices in a laboratory environment and/or an operator's network environment. For example, the one or more simulation devices can perform one or more or all functions while being fully or partially implemented and/or deployed as a part of a wired and/or wireless communication network to test other devices in the communication network. The one or more simulation devices can perform one or more or all functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The simulation device can be directly coupled to another device to perform testing, and/or can use over-the-air wireless communication to perform testing.

One or more simulation devices may perform one or more functions including all functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the simulation device can be used in a test laboratory and/or a test scenario of a wired and/or wireless communication network that has not been deployed (eg, tested) to perform testing of one or more components. The one or more simulation devices may be test devices. The simulation device may use direct RF coupling and/or wireless communication via an RF circuit (for example, the circuit may include one or more antennas) to transmit and/or receive data.

The broad classification of use cases for emerging 5G systems includes enhanced mobile broadband (eMBB), large-scale machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC). Different use cases can focus on different requirements, such as higher data rates, higher spectral efficiency, low power and higher energy efficiency, lower latency, and higher reliability. For various deployment scenarios, consider a wide range of spectral bands ranging from 700 MHz to 80 GHz.

As the carrier frequency increases, path loss becomes a limit that may hinder the guarantee of adequate coverage. Transmission in millimeter wave (mmW) systems may suffer from non-line-of-sight losses (eg, diffraction loss, penetration loss, oxygen absorption loss, leaf loss). During the initial access, the base station and the WTRU can overcome this path loss to discover each other. Some embodiments use a complex number of antenna elements (e.g., tens or hundreds) to generate beamforming signals (e.g., to compensate for such path loss by increasing the beamforming gain). Examples of beamforming techniques may include digital beamforming, analog beamforming, and/or hybrid beamforming.

Integrated access and backhaul (IAB) can be used in NR. For example, cellular network deployment scenarios and applications may include support for wireless backhaul and relay links, so that NR cells can be deployed flexibly and/or densely without proportionally denser transmission networks. Compared to LTE, the expected larger bandwidth available for NR (for example, due to mmW spectrum usage) and the local deployment of massive MIMO or multi-beam systems in NR can create opportunities to deploy IAB links. This allows for easier deployment of dense networks of self-backhauling NR cells in a more integrated manner by establishing many control and data channels and procedures defined for the access provided by the WTRU. FIG. 2 shows an exemplary NR network deployment 200 with IAB links 204 and 210. In an exemplary NR network deployment 200, the relay nodes (eg, relay transmission reception point, rTRP) 206 _A- 206 _C can be multiplexed in time, frequency, and/or space (eg, beam-based operation) take the backhaul link 210 and link 204, to provide network access to the WTRU 212 _A -212 _C. In this example, the relay node 206A also has an optical fiber transmission backhaul link 208.

Different links can operate on the same or different frequencies. Relay nodes operating in this way may be referred to as in-band relay and out-of-band relay, respectively. Effective support for out-of-band relay may be important for certain NR deployment scenarios. Because the access links may operate on the same frequency, the requirement for in-band relay operation may imply tighter interaction to accommodate duplex constraints and avoid or mitigate interference. There may be challenges in operating NR systems in mmW spectrum, such as severe short-term congestion, which may not be easily mitigated by current radio resource control (RRC)-based handover mechanisms. This may be due to the fact that the completion of the RRC-based procedure requires a larger time scale than short-term blockade. Techniques for overcoming short-term congestion in mmW systems may include RAN-based (e.g., fast RAN-based) mechanisms for switching between rTRP. These technologies may or may not involve the core network. An integration framework that allows fast switching of access links and backhaul links can be used to alleviate short-term congestion of NR operations in mmW spectrum and/or to facilitate the deployment of self-backhauled NR cells. Some embodiments may use over-the-air (OTA) coordination between rTRPs to mitigate interference and support end-to-end routing and optimization. IAB may be beneficial during rollout and initial network growth phases. In order to take advantage of these benefits, IAB can become available when NR is promoted.

Several use cases can be applied to 3GPP Internet of Vehicles (V2X), such as vehicle formation, extended sensors, advanced driving, and remote driving. Each exemplary use case group can have different latency, reliability, and data rate requirements. Table 1 shows the exemplary requirements of these exemplary use case groups. Here, the user, UE, WTRU, and vehicle WTRU may equally and interchangeably refer to the vehicle. Use case group End-to-end dive time (ms) reliability(%) Data rate (Mbps) Vehicle formation 10 99.99 65 Advanced driving 3 99.999 53 Extended sensor 3 99.999 1000 Remote driving 5 99.999 UL: 25, DL: 1 Table 1: Exemplary requirements for V2X use cases

The use cases in each use case group can have different ranges of latency, reliability, and data rate requirements. For example, the lower degree of automation in the video sharing scenario of the extended sensor use case group may have a latency requirement of 50 ms, a reliability requirement of 90%, and a data rate of 10 Mbps, while the sensing between WTRUs supporting V2X applications The higher degree of automation in the information sharing of the detector can have a latency requirement of 3 ms, a reliability requirement of 99.999%, and a data rate of 25 Mbps.

Different transmission modes can be defined in 3GPP V2X. For example, the vehicle may be in transmission mode 3 (i.e., mode 3 user) or may be in transmission mode 4 (i.e., mode 4 user). Mode 3 The WTRU can directly use the resources allocated by the base station for side link (SL) communication between vehicles (or between vehicles and pedestrians). Mode 4 The WTRU may obtain a list of candidate resources allocated by the base station, and may select resources from the candidate resources for the WTRU to use for SL communication. The terms user, WTRU or UE can also refer to vehicles here.

FIG. 3 is an exemplary side link WTRU information exchange procedure for the communication between the (vehicle) WTRU 302 and the base station (gNB/eNB) 304 for V2X side link transmission, for example, according to 5G NR V2X and/or LTE V2X 300's communication map. Once the WTRU 302 is camped on the cell associated with the gNB/base station (eNB) 304, the WTRU 302 may receive System Block (SIB) Type 21 (SIB21) 306, which may include the V2X side link communication configuration. For example, SIB21 306 may include SL-V2X-ConfigCommon Information Element (IE), which may include but is not limited to including components: v2x-CommRxPool , v2x-CommTxPoolNormalCommon , v2-CommTxPoolExceptional and/or v2x-InterFreqInfoList . v2x-InterFreqInfoList may be a list of adjacent frequencies (for example, up to seven adjacent frequencies) of V2X side link communication. The WTRU 302 may send the side link WTRU information 308 to the gNB/base station (eNB) 304 in one or more messages. For example, as part of the side link WTRU information 308, the vehicle WTRU 302 may send a message (one or more) to the gNB/base station (eNB) 304 to indicate to the gNB/base station (eNB) 304 that the WTRU 302 is interested (Or not interested) in receiving V2X side link communication and/or requesting the assignment and/or release of transmission resources for V2X side link communication. The WTRU 302 and the gNB/base station (eNB) 304 may exchange one or more RRCConnectionReconfiguration messages 310, which may include the SL-V2X-ConfigDedicated IE. For example, the SL-V2X-ConfigDedicated IE may include but is not limited to commTxResources and/or v2x-InterFreqInfoList .

The research project on NR V2X considers Uu-based side link resource allocation/reconfiguration to identify the LTE Uu interface and the enhancement of the NR Uu interface to control the NR side link from the cellular network and identify the enhancement of the NR Uu interface To control the LTE side link communication from the cellular network. In the context of LTE V2X synchronization, when the WTRU connects to the eNB, the WTRU may already have cell timing. If the WTRU is not within the coverage of the eNB, the WTRU may use the Global Navigation Satellite System (GNSS) for timing synchronization. When the WTRU cannot find the timing from the eNB or GNSS, the WTRU may rely on the side link WTRU to obtain timing information. GNSS satellites have atomic oscillators that provide a stable and accurate time reference. The GNSS receiver can track signals from a plurality of satellites and retrieve a local time reference with an absolute error of less than 1 μs for the global positioning system (GPS) receiver. For coordinated multipoint transmission, the residual using GPS can be about 10 ns. GNSS can be used for frequency synchronization by phase-locking the local oscillator to the incoming signal and stabilizing the carrier frequency. For modern vehicles equipped with GNSS receivers, GNSS solutions for synchronization can be used for V2X.

For example, for synchronization in V2X, the WTRU may receive side link synchronization signals (SLSS) from other WTRUs on the side link. The SLSS may include a primary side link synchronization signal (PSSS), a secondary side link synchronization signal (SSSS), and/or a physical side link broadcast channel (PSBCH) signal, which may further include synchronization information. The WTRU can use the information carried in the SLSS to obtain timing information. The threshold for synchronization measurement (for example, synchronization threshold) can be received in RRC messaging (for example, v2x-SyncConfig and/or SL-V2X-Preconfiguration IE).

The SLSS may include, but is not limited to, any one or more of the following exemplary signals: PSSS, SSSS, PSBCH, and/or demodulation reference signal (DMRS) for demodulating the PSBCH. For example, PSSS and SSSS can be transmitted in adjacent time slots in the same subframe. Side link-ID (SID) can be divided into two groups. For example, SIDs in the range {0, 1, ..., 167} may be reserved for WTRUs within coverage (ie, WTRUs that can receive a signal strong enough to connect with cells associated with the eNB), and SIDs in the range {168,169,..., 335} can be used for WTRUs outside the coverage area. The sub-frames used as radio resources to transmit SLSS and PSBCH can be configured by higher layers.

V2X can include unlicensed band operation. In the unlicensed frequency band, the gNB or WTRU may need to perform the first listen and wait (LBT) procedure before accessing the unlicensed wireless channel. The details of the LBT program may vary depending on the management requirements of the unlicensed channel. The LBT procedure may include fixed and/or random duration intervals during which a wireless node (such as a gNB or WTRU) monitors the wireless medium (such as detecting the energy level of the wireless medium), and if it detects from the wireless medium If the measured energy level is greater than a critical value (for example, it is specified by the administrator), the gNB or WTRU can avoid transmitting any wireless signals; otherwise, the wireless node can transmit signals after the LBT procedure is completed. In some management systems, the LBT program may be mandatory for unlicensed channel use (used by unlicensed users). Therefore, various LBT categories are adopted in 3GPP License Assisted Access (LAA) (version 13), enhanced LAA (eLAA) (version 14), and further enhanced LAA (feLAA) (version 15). Some implementations use the LBT category 4 (CAT4) scheme for some or all use cases, as used in LAA/eLAA.

In one example, the LBT CAT4 procedure can be started when the base station (or WTRU) attempts to transmit control or data in an unlicensed channel. The base station (or WTRU) may perform an initial clear channel assessment (CCA) to determine whether the channel is idle for a period of time (for example, the sum of a fixed period and a pseudo-random duration). The availability of the channel can be determined by comparing the energy (ED) level detected on the bandwidth of the unlicensed channel with the energy threshold (for example, set by the administrator). If it is determined that the channel is idle, the base station (or WTRU) can continue to transmit on the channel. If it is determined that the channel is in use, the base station (or WTRU) may perform a time-slotted random backoff procedure. In an exemplary time slotted random backoff procedure, random numbers are selected from a specified interval that can be called a contention window. The backoff countdown can be obtained, and it can be verified whether the channel is idle, and when the backoff counter becomes zero, the transmission can be started. After the base station has gained access to the channel, the base station is only allowed to transmit for a limited duration, which may be referred to as the maximum channel occupation time (MCOT). The CAT4 LBT program with random backoff and variable contention window size can facilitate fair channel access and coexistence with other radio access technologies (RATs) such as Wi-Fi and other LAA networks.

In the IAB system, in some cases, the random access channel (RACH) can be accessed by the WTRU in the access link and the IAB node in the backhaul link. The IAB node may be gNB, TRP, rTRP, or BS, and is used interchangeably with gNB, TRP, rTRP, and BS in this document. The IAB node can provide integrated access link and backhaul link functions. The access distance of the IAB node may be greater than the access distance of the WTRU. Therefore, the RACH configuration and procedures can be designed to meet the RACH requirements of both the IAB node and the WTRU. In the example of supporting the RACH transmission of the IAB node and the WTRU, the physical random access channel (PRACH) configuration, PRACH preamble format, preamble configuration and/or RACH procedure can support RACH transmission from the WTRU and RACH transmission from the IAB node Multitasking.

In the IAB system, resources can be allocated between the backhaul link and the access link. For example, time division multiplexing (TDM), frequency division multiplexing (FDM), and/or space division multiplexing (SDM) techniques can be used in the IAB system to allocate resources, and resources can be allocated dynamically or semi-statically. In implementations where FDM and/or SDM are used for multiplexed backhaul links and access links, cross-link interference may occur.

In the IAB system, the periodicity of the PRACH configuration of the IAB node may be longer than the periodicity of the PRACH configuration of the WTRU. For example, a long PRACH configuration period may be configured for the IAB node, because in some cases, the IAB node may not transmit PRACH as frequently as the WTRU. However, in the case where the IAB node needs to perform random access or transmit a preamble, a long PRACH configuration period may introduce a long access delay. Therefore, a complex number procedure can be used to reduce the RACH delay of the IAB node corresponding to the long PRACH configuration period.

In the IAB system using unlicensed spectrum, after receiving one or more preambles, the gNB or IAB node can determine the random access response (RAR) window and transmit the RAR. The RAR window may be determined by the WTRU. The RAR window determined by the WTRU may be different from the RAR window determined by the gNB or IAB node, for example, if the gNB or IAB node misses the preamble. After receiving several preambles, the gNB or IAB node can transmit RAR. The plural program can determine how many RARs can be sent by the gNB/IAB node and how many RACH messages the gNB/IAB node can configure with the plural RAR 3 (Msg3, for example (RRC connection request message) UL authorization.

When the WTRU is operating in V2X mode, the resources used for feedback (e.g., ACK/NACK) may be known to the WTRU that can transmit data (e.g., in terms of time and frequency). The complex number procedure can facilitate avoiding conflicts between transmissions of WTRUs that use the ACK/NACK feedback resource, and/or resolve conflicts between resources used for data transmission and feedback.

An exemplary method of PRACH configuration conflict avoidance in the IAB system can be used. In one example, the IAB system can support network flexibility to configure backhaul RACH resources. Figure 4 shows an exemplary PRACH configuration 400 in an exemplary NR IAB network deployment. The exemplary PRACH configuration having a different hop backhaul IAB WTRU comprising step (hop order) 402 ₁ -402 ₄ is. Network can be configured to offset PRACH opportunity in order to move the terminal (MT) IAB nodes ₄₀₆₁ and ₄₀₆₄ carried out across the adjacent TDM backhaul RACH resources jump. The offset can be defined according to K durations, where the duration can be, for example, a radio frame, a sub-frame, a time slot, a micro time slot, a non-time slot, and/or an OFDM symbol.

In the exemplary PRACH configuration 400, WTRU 402 ₁ -402 ₄ may be configured with the same PRACH configuration used for initial access, i.e., PRACH configuration _4041. In an example, with an even hop node IAB order ₄₀₆₂ and ₄₀₆₄ are arranged with the same initial access for PRACH configuration ₄₀₄₂ that may be used WTRU PRACH 402 ₁ -402 ₄ disposed _4,041 different; with odd jump order IAB node ₄₀₆₃ may be configured with the same initial access for PRACH configuration _4043, which may be configured 404 ₁ IAB having a node and a different order and for even-hop WTRU PRACH 402 ₁ -402 ₄ of The PRACH configuration 404 _{2 of} 406 ₂ and 406 ₄ are different. In an example, the PRACH configuration 404 ₁ may be the same as the R15 PRACH configuration. In an example, the PRACH configuration 404 ₂ and/or 404 ₃ may have a longer periodic period 412 than the periodic period 410 of the PRACH configuration 404 ₁ . In an example, PRACH configuration ₄₀₄₂ and / or ₄₀₄₃ may have a longer PRACH format and / or may have other differences in configuration of the R15 PRACH. The PRACH configurations 404 ₁ , 401 ₂ and 404 ₃ can use TDM to multiplex with each other, as shown in the exemplary schedule 430.

As shown in the exemplary PRACH configuration 400, the IAB node's PRACH configuration periodicity may be longer than the WTRU's PRACH configuration periodicity. If the IAB node does not transmit PRACH as frequently as the WTRU, the relatively long PRACH configuration period of the IAB node may be appropriate. However, if the IAB node needs to perform random access or transmit a preamble, a relatively long PRACH configuration period may introduce a long delay. A complex number procedure can be used to reduce or avoid the RACH delay of the IAB node caused by the long PRACH configuration period.

The exemplary procedure for solving the RACH delay of the IAB node due to the long PRACH configuration period may consider that the IAB node is not mobile, and the position from an IAB node to its parent node may be relatively fixed. In this case, the synchronization signal block (SSB) received from a specific IAB parent node may be a relatively fixed subset of all transmitted SSBs. In order to reduce the RACH access delay of the IAB node, the IAB node can associate PRACH with a subset of SSBs instead of all SSBs (that is, the IAB node can only report one SSB from one SSB subset, instead of reporting from all SSBs SSB). FIG. 5 shows an exemplary SSB configuration 500 provided by the IAB node 502, and specifically shows the SSB subset information SSB1-SSB8 broadcast as part of the PRACH configuration in each corresponding sector B1-B8.

In the exemplary SSB configuration 500, the IAB donor 502 can transmit eight SSBs: SSB1-SSB8. If all SSBs (SSB1-SSB8) are mapped to RACH occasions (RO) one-to-one, the delay of SSB can be as long as eight ROs. However, if SSB subset information is used or configured, the WTRU (not shown) can only be associated with (one or more) SSBs in the corresponding SSB subset, and the delay can be reduced. Different (one or plural) preamble subsets, (one or plural) preamble roots, and/or different FDM multiplexed ROs can be used to indicate the SSB subsets (and the SSB subsets can therefore be distinguished from each other) . In one example, some SSB subsets may be isolated geometrically (ie, spatially).

Figure 6 shows an SSB subset assignment procedure 600 for latency reduction. Each SSB subset can have one or more SSBs. For example, the SSB subset may include two SSBs (eg, SSB subsets {SSB1, SSB2}, {SSB3, SSB4}, {SSB5, SSB6}, and/or {SSB7, SSB8}). If the IAB node detects SSB3, based on the SSB subset, the IAB node can select SSB3 and SSB4 to associate with the RO. The subset {SSB1, SSB2} and the subset {SSB5, SSB6} can use the same PRACH resources, for example, when the subset {SSB1, SSB2} and the subset {SSB5, SSB6} are naturally isolated due to non-overlapping beams /Preamble resource. In one example, the SSB subset method for SSB configuration can reduce the RACH delay of the access node, IAB node and/or gNB in the unlicensed band.

Any of the following procedures can be used for unlicensed operations of IAB. In one example, for example, in the case of LBT failure, the preamble power ramp may not be performed, and the preamble transmission counter may not be incremented. When the UL LBT is successful but the RAR is not received from the gNB within the RAR window, the power ramp procedure can be used. In an exemplary process, the LBT can be executed at each RO slot. The indicator (for example, one-bit indicator) can be used to indicate that the channel (for example, cell public PDCCH, group public PDCCH, broadcast DL channel, or other PHY transmission) is in the previous RO slot Free or busy. This exemplary procedure may facilitate the WTRU to determine whether the reason why the WTRU did not receive the RAR is due to the hidden node interference of the gNB.

In one example, a complex PRACH transmission can be performed before the RACH Msg2 (eg, RAR) reception in the RAR window for initial access. The number of allowed transmissions can be predefined or can be indicated (for example, indicated in the remaining minimum system information (RMSI)). In some cases, multiple RARs may be sent to the same WTRU. In the case where the WTRU transmits a complex preamble, the same complex preamble across different ROs may be used, and/or the complex preamble may be different but may have a pre-configured or indicated order in different ROs.

In another example, the RAR may be defined in a specific way for the WTRU transmitting the complex preamble. If the WTRU transmits a complex preamble, the RAR window may be associated with the first preamble transmission. The gNB that missed the first preamble may have an incorrect RAR window. In one example, as long as the (RACH) Msg2 is not received before the end of the RAR window associated with the previous preamble transmission, the WTRU may transmit one or more preambles during any RO period until the number of preamble transmissions or reception is reached To RAR. Each time the gNB receives a preamble from the WTRU, the gNB may send the RAR within the RAR window.

In one example, if the WTRU transmits a complex preamble, the gNB may not receive any preambles, some preambles, or all preambles. In one example, the gNB can determine the RAR window and send the RAR after receiving one or more preambles. In one example, the RAR window may be derived by the WTRU, which may be different from the RAR window derived by gNB (for example, because the gNB may have missed one or more preambles). In one example, the gNB may not know which preambles are from the same WTRU (or from different WTRUs). In one example, the gNB can independently process the received preamble. For example, the gNB may use independent RAR and RAR windows for each received preamble, regardless of whether the preamble comes from the same WTRU or a different WTRU.

After receiving several preambles, the gNB can send the corresponding RAR. The gNB can use a complex number program to determine the number of RARs that the gNB can send, and the number of Msg3 UL grants that the gNB can configure with the complex number of RARs.

In one example, the gNB can distinguish preambles from the same WTRU or different WTRUs. In one example, gNB may use plural RARs with different UL grants. In the example, multiple UL authorizations can be reserved. In one example, the WTRU may try to send a plurality of Msg3 using a plurality of UL resources. The use of multiple UL grant reservations can lead to multiple UL/DL switching and resources.

In an example, plural RAR may be used for plural (for example, one or plural) UL grants, where the plural UL grants may be the same. The configuration method of the UL grant in the RAR can make the UL grants in the plural RAR the same. The Msg3 UL grant in the time domain may have an offset from the end of the RAR window. In one example, gNB can retain the same UL grant, which results in fewer DL/UL switching. In this case, the same RAR window can be used for WTRU and gNB.

In an example, one RAR may be used for one UL grant for a given WTRU. The gNB can respond to the first received preamble and ignore the subsequent preamble; this method may not alleviate the RACH delay caused by LBT. In one example, a RAR may be used for multiple UL grants for a given WTRU.

In one example, after receiving the plural RAR from the gNB, there may be plural Msg3 UL grants. In one example, the WTRU responds to those Msg3 UL grants by sending Msg3 in all UL grants. In this case, the chance of Msg3 transmission failing due to LBT failure may decrease. In another example, the WTRU may transmit only one Msg3 in response to multiple Msg3 UL grants, which can reduce interference and overhead. If multiple Msg3 are transmitted, the gNB may not receive any transmitted Msg3. In this case, the gNB may assign Msg3 retransmissions for each Msg3, and/or the WTRU may have multiple Msg3 UL grants.

In an example, the gNB may have received some but not all of the plural Msg3. Figure 7 shows a signaling diagram of an exemplary RACH message exchange 700 between WTRU 702 and gNB 704, which can be used for unlicensed operation in an IAB system. In the exemplary RACH message exchange 700, the gNB did not successfully receive Msg1 706 and Msg3 718 from the WTRU 702, while the gNB successfully received Msg1 708, Msg1 710, and Msg3 716 from the WTRU 702. In this case, the gNB may send Msg4 720 (after sending RAR 712 and 714) to the WTRU 702 in response to the received Msg3 716, and/or may use it for Msg3 replay for the unreceived Msg3 718. The 722 assignment is sent to the WTRU 702. In one example, because at least some Msg3 (Msg3 716) has been received by the WTRU 702, the gNB may not assign Msg3 retransmission.

In one example, the gNB may receive all Msg3 from the WTRU. The gNB may send Msg4 to the WTRU for all received Msg3. In one example, the gNB may notify the WTRU that all Msg3s are from the same WTRU because they have the same WTRU ID. In one example, the gNB may need to know whether it has received Msg3 from the same WTRU. In some examples, for each Msg3, the gNB may include auxiliary information to indicate how to present or use the Msg3 UL authorization and what Msg3 UL authorization to present or use. For example, for each Msg3, gNB may indicate all Msg3 UL grants that a particular WTRU is using. In one example, each Msg3 may indicate all RARs that the WTRU has received. The auxiliary information may include, for example, a random access wireless network temporary identifier (RA-RNTI), a preamble ID, a preamble index, a RACH resource index, and/or any other ID or index.

The complex number procedure for preamble LBT congestion reduction can be used for FDM UL transmission. Figure 8A shows an exemplary IAB network deployment 800. FIG. 8B shows a signaling diagram of an exemplary RACH message exchange 801B according to an exemplary transmission timing of an exemplary IAB network deployment 800. FIG. 8C shows a signaling diagram of another exemplary RACH message exchange 801C according to another exemplary transmission sequence using the exemplary IAB network deployment 800.

In one example, the WTRU 802 may perform RACH, and the WTRU 804 may be in RRC connected mode. The WTRU 802 may have a time delay of T1 (ie, the transmission delay between gNB 806 and WTRU 802), and the WTRU 804 may have a time delay of T2 (ie, the transmission delay between gNB 806 and WTRU 804). When the WTRU 802 is transmitting the preamble 816, the WTRU 804 may also be scheduled to transmit UL data 812 in the same or overlapping time slots, as shown in FIG. 8B. For example, the WTRU 804 may use a timing advance (TA) T3 to transmit the UL data 812, and the WTRU 802 may not know the TA T3 (e.g., T3<T1+T2). The WTRU 802 and/or 804 may perform LBT 813/811 based on the timing of the SSB reception 810 from the gNB 806. In this case, the UL data transmission 812 of the WTRU 804 may interfere with the LBT 813 of the WTRU 802 and block the preamble transmission 816 of the WTRU 802.

In order to avoid blocking the preamble transmission 816, the UL transmission 820 in the same time slot as the RO can use the guard period 823 at the beginning (and after LBT821) of the UL transmission 820 scheduled in the same time slot as the RO ( Gap or duration), as shown in the exemplary RACH message exchange 801C.

FIG. 9A shows an exemplary IAB network deployment 900 in which WTRUs 902 and 904 are close to each other and located at the boundary of the same cell of gNB 906. FIG. 9B shows a transmission diagram of an exemplary RACH message exchange 901 according to an exemplary transmission timing of the exemplary IAB network deployment 900. The time delay from the cell boundary to gNB 906 is denoted as T _cell . The WTRU 902 and/or 904 may perform LBT 913/911 based on the timing of the SSB reception 910 from the gNB 906. In order to avoid blocking the preamble transmission 916 of the WTRU 902, a guard period 915 (duration) with a duration of 2T _cell may be used at the beginning of the UL transmission 912 of the WTRU 904. For example, the guard period 915 may be several OFDM symbols in the duration.

In one example, the periodicity of the SS/PBCH block can be long in the IAB system (for example, longer than 20ms). The long periodicity of the SS/PBCH block may allow the IAB node (for example, the IAB donor node) to transmit the SS/PBCH block with a longer periodicity (for example, when the IAB donor node is operating in non-standalone mode (NSA)) . For example, the IAB node can transmit synchronization signals for the physical broadcast channel (SS/PBCH) block with a periodicity of 80 ms or 160 ms or longer. In one example, the IAB node also transmits RMSI in a long period. For example, the IAB node can transmit RMSI with a longer period than the SS/PBCH block. RMSI may only be needed for the initial access performed by the IAB. Therefore, frequent transmission of RMSI may not be used. For example, the IAB node may transmit the SS/PBCH block with a periodicity of 160 ms or 320 ms or longer. For IAB nodes, RMSI can be used to obtain minimum system information for initial access. For example, the RACH configuration can be part of the RMSI for IAB. Some information in RMSI may not be used.

The SS/PBCH block and RMSI can be transmitted using the same or different periodicity. If the SS/PBCH block and RMSI are transmitted with the same periodicity, additional information may not be needed in the RMSI. However, if different periodicities are used to transmit SS/PBCH blocks and RMSI, additional information may be required (for example, in SS/PBCH or RMSI, to indicate the presence or absence of SS/PBCH or RMSI). If the SS/PBCH block is transmitted less frequently than RMSI, additional information may be required (for example, in RMSI, to indicate the presence or absence of SS/PBCH). In another example, if SS/PBCH blocks are transmitted more frequently than RMSI, additional information may be required (for example, in PBCH, to indicate the presence or absence of RMSI). In one example, there may be an association between SS/PBCH and RMSI. For example, if SS/PBCH blocks are transmitted less frequently than RMSI, additional information may be required (for example, in RMSI, to indicate that SS/PBCH does not exist and the association is not maintained). However, if SS/PBCH blocks are transmitted more frequently than RMSI, additional information may be required (for example, in PBCH, to indicate that RMSI does not exist and the association is not maintained).

In an example, the SS/PBCH and RMSI may have the same periodicity. For example, the same periodicity (for example, 160 ms longer than the preset 20 ms) can be used to transmit SS/PBCH and RMSI. It is possible (for example, by gNB or network or transmitter) to indicate the same or different periodicity for SS/PBCH and RMSI transmission. In addition, when there are different periodicities for SS/PBCH and RMSI transmission, it is also possible (for example, by gNB or network or transmitter) to indicate whether the periodicity of SS/PBCH is shorter or longer than RMSI. The presence/absence of SS/PBCH or RMSI can also be indicated to the WTRU accordingly.

The complex program for V2X feedback signals can be used with or without IAB. In one example, the physical side link feedback channel (PSFCH) can be used for V2X communication. The PSFCH can be used to carry any feedback information, including but not limited to any hybrid automatic repeat request (HARQ) feedback information, ACK/NACK information and/or channel status information (CSI).

In an exemplary scenario, a first WTRU that has transmitted data to a second WTRU may try to receive a type of feedback (e.g., ACK and/or NACK feedback) from the second WTRU. In this example, in order to successfully receive the feedback information, the first WTRU may need to know the side link resources used to carry the feedback information. The side link resources used for the feedback from the second WTRU may include, but are not limited to, time (e.g., time slot index), frequency (e.g., subcarrier index), and/or code (e.g., spread sequence index). The complex procedures used for V2X feedback signals should ensure that the feedback from multiple WTRUs (e.g., where the expected receivers of the feedback may be the same or different) does not conflict, or that the collision probability is maintained at an acceptable low level throughout the network operation ( For example, below the threshold level).

According to an exemplary procedure for V2X feedback signals, the resources used for feedback (e.g., ACK/NACK) are known in time and frequency to the WTRU that has transmitted data (ie, the intended recipient of the feedback), so that Other WTRUs do not conflict with the feedback transmission (for example, ACK/NACK) in the V2X feedback resource. The (for example, ACK/NACK) feedback resource may be determined by the resource used to transmit the data corresponding to the feedback. FIG. 10 shows a resource diagram of an exemplary time slot format 1000, in which a feedback resource 1022 is derived from a resource 1020 for data transmission. In time slot n , the WTRU 1001 uses the physical side link shared channel (PSSCH) 1010 located in the frequency resource 1020 and in the frequency range F=[F1 to F2] to transmit data to the WTRU 1002. In a later time slot (time slot n+1 ), the WTRU 1002, for example, uses PSFCH 1014 to transmit feedback to the WTRU 1001 (eg, ACK or NACK for the transmission in time slot n ). In one example, it may be predetermined (eg, configured) when to transmit the data and when to transmit the time slot index (eg, n, n+1) of the feedback corresponding to the data transmission. In some examples, this timing relationship can be indicated in the scheduling assignment corresponding to the data transmission. The index of the OFDM symbol used to carry the feedback in the time slot may also be predetermined or signaled.

In one example, the frequency resource 1022 used by the WTRU 1002 to send feedback to the WTRU 1001 may be within the same frequency resource range F=[F1 to F2] used for data transmission from the WTRU 1001 to the WTRU 1002. By selecting resources from the range F = [F1 to F2], the feedback frequency resource 1022 may not overlap with other resources in the same time slot n+1, where the other resources are, for example, the WTRU 1002 using PSSCH 1012 to transmit data to Resources used by another WTRU 1024.

FIG. 11 shows a resource diagram of another exemplary time slot format 1100, in which the feedback resource 1122 is derived from the resource 1120 for data transmission. In time slot n , the WTRU 1101 uses the PSSCH 1110 in the frequency resource 1120 and is located in the frequency range F=[F1 to F2] to transmit data to the WTRU 1102. In the same time slot n , the WTRU 1102, for example, uses PSFCH 1112 to transmit feedback to the WTRU 1101 (e.g., ACK or NACK for the transmission in time slot n ). The frequency resource 1122 used by the WTRU 1102 to transmit the feedback to the WTRU 1101 may be within the same frequency resource range F=[F1 to F2] used for data transmission from the WTRU 1101 to the WTRU 1102.

When the feedback is sent in a different time slot than the data (for example, as shown in Figure 10), it is possible that another WTRU is in the same time slot as when the feedback is scheduled for transmission (for example, time slot n+ 1) The resources in the frequency range F1 to F2 have been reserved. In one example, the third WTRU may not be in frequency range F and/or transmit on the OFDM symbol where the feedback is scheduled to be transmitted (ie, those resources may be excluded from transmissions by other WTRUs). FIG. 12 shows a resource diagram of another exemplary time slot format 1200, in which the feedback resource 1222 is derived from the resource 1220 for data transmission. In time slot n , the WTRU 1201 uses the PSSCH 1210 located in the frequency resource 1220 and the frequency range F=[F1 to F2] to transmit data to the WTRU 1202. In a later time slot (time slot n + 1), the WTRU 1202, for example, uses PSFCH 1014 to transmit a feedback to the WTRU 1201 (eg, ACK or NACK for the transmission in time slot n ). The frequency resource 1222 used by the WTRU 1202 to transmit the feedback to the WTRU 1201 may be in the same frequency resource range F=[F1 to F2]. In this example, the WTRU 1203 may use the PSSCH 1212 which is also located in the frequency resource 1220 to transmit data (to another WTRU). In this case, the WTRU 1203 may perform puncturing or rate matching on the transmission block of its data transmission, so that it and the feedback resource 1222 are suitable for the frequency resource 1220. In this case, the WTRU 1203 (and any other WTRUs attempting to reserve resources) may know the time/frequency resources 1222 allocated for PSFCH transmission 1214. For example, the WTRU may transmit a reservation signal to reserve resources for scheduled assignment (SA)/data transmission. Due to the predetermined timing relationship between the data transmission (for example, PSSCH 1210) and the corresponding feedback (PSFCH 1213), the WTRU receiving the reserved signal can know the time and/or frequency resources within which the feedback will be sent. For example, in the exemplary time slot format 1200 of FIG. 12, the WTRU 1201 may reserve resources 1220 in time slot n and frequency range F by sending (one or more) reservation signals (not shown). Other WTRUs (for example, WTRU 1203) receiving the reserved signal(s) may also determine that certain OFDM symbols in time slot n+1 and frequency range F are also reserved for feedback to WTRU 1201. The time slot index of the PSFCH 1214 can be indicated in the reserved signal.

Some data transmissions in the IAB system may not require feedback. For example, when the WTRU reserves resources, the reservation signal may include information about whether the reservation will require feedback. For example, a one-bit flag can indicate whether PSFCH should be used. In another example, another parameter in the signal can implicitly indicate whether feedback is required. For example, the reserved signal may indicate the type of service (for example, unicast with feedback, group broadcast with feedback, group broadcast without feedback, broadcast), and the use of feedback may be implied from the service type.

FIG. 13 shows a resource diagram of an exemplary time slot format 1300 including two SA phases (SA phase-1 and SA phase-2). In time slot n , the WTRU 1301 uses the PSSCH 1310 located in the frequency resource 1320 and in the frequency range F=[F1 to F2] to transmit data to the WTRU 1302. In a later time slot (time slot n +1), the WTRU 1302 uses PSFCH 1312 to transmit feedback to the WTRU 1301 (eg, ACK or NACK for the transmission in time slot n ), for example. The frequency resource 1322 used by the WTRU 1302 to send feedback to the WTRU 1301 may be within the same frequency resource range F=[F1 to F2] used for data transmission from the WTRU 1301 to the WTRU 1302. The SA and the physical side link control channel (PSCCH) may refer to the same channel. At least one of the complex SA phases can be decoded by all or a subset of WTRUs in the vicinity that can receive the first phase SA. The first stage SA and the position of the corresponding PSFCH 1312 may be associated (for example, the first stage SA may directly or indirectly indicate the position of the PSFCH 1312). Any one or more of the following can be applied (note that these methods can also be similarly applied to SA phase-2): The position of SA phase-1 can implicitly indicate the position of PSFCH 1322; used to carry the SA phase The control resource set (CORESET) of -1 can implicitly indicate the location of PSFCH 1322; SA stage-1 can indicate whether the receiving WTRU needs to send feedback (for example, the WTRU can be used by gNB, base station, or such as a fleet manager WTRU) Other transmission WTRU configurations to provide feedback); the location of PSFCH 1312 (for example, frequency and time resources 1322) and whether PSFCH 1312 feedback is required can be indicated by a combination of SA phase I and/or SA phase II; and/or PSFCH 1312 The location (for example, frequency and time resources 1322) and whether PSFCH 1312 feedback is required can be indicated by a combination of SA phase-2 and a reserved signal (for example, the reserved signal may be the same as or different from the SA phase-1).

In some examples, in the case where the PSFCH and the stage-1 SA are mapped to the same subcarrier (for example, in the same time slot or different time slots), the position of the stage-1 SA may be implicitly indicated The time and frequency resources of the PSFCH. In some examples, the PSFCH may be mapped to a subset of subcarriers used by the phase-1 SA. For example, a specific subset can be configured by the central controller.

In the example in which the CORESET used to carry the SA-I can implicitly indicate the location of the PSFCH, the CORESET can consist of time/frequency resource units, and one or more of these time/frequency resource units can be associated with the PSFCH Associated with the frequency and/or time/frequency location. In the example where SA-I can also indicate whether the receiving WTRU needs to send feedback, this information can include at least one bit and can be encoded as part of the SA-I message. In an example where the demodulation reference signal (DM-RS) of SA-I or some other type of reference signal (RS) associated with SA-I can be used to indicate whether feedback is required, the RS can include two parts, And these parts can be scrambled with [1 1] or [1 -1] to show one-bit information. In one example, the cyclic shift and/or sequence index of the RS can be used to indicate the bit information.

In the case that a combination of phase-1 SA and phase-2 SA can be used to indicate the location (time/frequency resource) of the PSFCH and whether PSFCH feedback is required, phase-1 SA can indicate whether there will be PSFCH transmission, and phase- 2 SA can indicate the location (time/frequency resource) of the PSFCH, so that the PSFCH need not be located in the same frequency range F used for SA (or PSSCH). For example, the stage-2 SA may include coded bits indicating the time and/or frequency position of the PSFCH. The WTRU that is listening for the transmission may decode the Phase-1 SA and receive information about the reservation of the transmitting WTRU. If any other WTRU (e.g., UE 1203 in Figure 12) tries to access the same resource pool, the WTRU may also decode the Phase-2 SA to determine the time/frequency resources (location) of the PSFCH. The WTRU may determine to use or not to use the same resource allocated to the PSFCH (for example, choose to use the resource, or allow or prohibit the use of this resource).

In the example where the time/frequency resource (location) of the PSFCH and whether PSFCH feedback is required can be indicated by the combination of stage-1 SA and reserved signal (for example, if the reserved signal is different from SA-I), the parameters (for example, signal The service type information) may be associated with the existence of the PSFCH or may indicate the existence of the PSFCH, and the time/frequency resource (location) of the PSFCH may be indicated by the coded bits in the stage-1 SA. In one example, the stage-1 SA may have one of multiple possible formats, and at least one of these formats may include PSFCH information, and at least one of these formats may not include PSFCH information. In one example, the m-bit phase-1 SA format may include at least one bit field for the PSFCH, and the n-bit phase-1 SA format may be known (eg, known by other WTRUs) without PSFCH Information (for example, meaning that the upcoming transmission will not require feedback).

In one example, another parameter in Downlink Control Information (DCI) can implicitly indicate whether the transmitter (eg, gNB, other transmitting WTRU, etc.) needs feedback. For example, the DCI may indicate the type of traffic (for example, unicast with feedback, group broadcast with feedback, group broadcast without feedback, broadcast). In an example, the plural stages of the SA may be transmitted in different time slots, and the DCI may be part of the stage-1 SA and/or the stage-2 SA. For example, the phase-1 SA can carry the traffic type information.

If a WTRU excludes PSFCH resources from its transmission (e.g., the example WTRU 1203 in FIG. 12), the WTRU may indicate the exclusion of PSFCH resources to its intended receiver so that the receiver can perform appropriate reception operations. In one example, the DCI in the SA transmitted by the WTRU may indicate whether any resources have been excluded from the transmission. For example, a one-bit flag can indicate whether the frequency range F on m OFDM symbols has been excluded. Referring to FIG. 13, if the frequency range used by the WTRU 1203 is greater than the frequency range 1222 of the PSFCH 1214, the WTRU 1203 may exclude all OFDM symbols carrying the PSFCH 1214.

In one example, a subset F of frequency resources may be allocated for PSFCH transmission. The WTRU that receives and decodes the PSCCH and/or the discovery channel or some other channel can know the time/frequency resources (location) of the PSFCH. For example, the WTRU and its intended receiver may have received information about the time/frequency resources (location) of the PSFCH. Based on this, the WTRU may skip PSFCH resources in its transmission (for example, by rate matching or puncturing), and the intended receiver will not expect any information bits from the WTRU on these resources.

FIG. 14 shows a resource diagram of an exemplary time slot format 1400 in which the feedback resource is derived from the resource used for data transmission. In time slot n , the WTRU 1401 uses the PSSCH 1410 to transmit data to the WTRU 1402 in the frequency resource 1420 in the frequency range ΔF. The WTRU 1402 monitors the signal rate range ΔF for the signal from the WTRU 1401 on the PSSCH 1410 (for example, a message carrying data) in the time slot n, where the frequency range ΔF may include corresponding plural resource blocks (RB). The WTRU 1402 determines the feedback frequency resource 1422 based on any or more of the following information: the frequency range ΔF; the number of RBs in the first complex number of RBs; and/or the identification code of the WTRU 1401. For example, the feedback frequency resource 1422 may be determined as a subset of the complex number of RBs in the frequency resource 1420. The WTRU 1402 uses the feedback frequency resource 1422 to send feedback information to the WTRU 1401 in time slot n+k (for example, ACK/NAK to confirm/negatively confirm the data sent by the WTRU 1401 on the PSSCH 1410 in time slot n). For example, the WTRU 1402 may use the feedback frequency resource 1422 to transmit HARQ feedback information to the WTRU 1401 on the PSFCH 1412. In time slot n+k, another WTRU 1403 may use a different frequency resource 1424 to transmit data to another WTRU 1404 on the PSSCH 1414, where the different frequency resource 1424 may not be the same as the frequency resource 1422 and/or frequency resource 1420 overlap.

FIG. 15 shows a resource diagram of an exemplary time slot format 1500 in which the feedback resource is derived from the resource used for data transmission. In time slot n , the WTRU 1501 transmits control information (for example, broadcast information on the side link) on the PSCCH 1508 in the frequency resource 1523 in the frequency range ΔFc. The frequency range ΔFc may be a subset of the frequency range ΔF, and the frequency resource 1523 may be a subset of the frequency resource 1520 used by the WTRU 1501 to transmit data to the WTRU 1502 using the PSSCH 1510 (for example, a subset of a plurality of RBs). The WTRU 1502 monitors the signal rate range ΔFc for the signal from the WTRU 1501 on the PSCCH 1508 (for example, a message carrying control information) in time slot n. The WTRU 1502 monitors the signal rate range ΔF in the time slot n to find the signal from the WTRU 1501 on the PSSCH 1510 (for example, a message carrying data). The WTRU 1502 determines the feedback frequency resource 1522 based on any one or more of the following information: the frequency range ΔF; the number of RBs in the plurality of RBs associated with the frequency resource 1520; the frequency range ΔFc; associated with the frequency resource 1523 The number of RBs in the plural RBs; and/or the identification code of the WTRU 1501. For example, the feedback frequency resource 1522 may be determined as a subset of the complex number of RBs in the frequency resource 1523. The WTRU 1502 uses the feedback frequency resource 1522 in time slot n+k to send feedback information (for example, ACK/NAK) to the WTRU 1501 to confirm/negate the data sent by WTRU 1501 on PSSCH 1510 in time slot n confirm). For example, the WTRU 1502 may use the feedback frequency resource 1522 to transmit HARQ feedback information to the WTRU 1501 on the PSFCH 1512. In time slot n+k, another WTRU 1503 may use a different frequency resource 1524 that does not overlap with frequency resource 1522 and/or frequency resource 1520 to transmit data to another WTRU 1504 on PSSCH 1514.

The exemplary procedure for the V2X feedback signal described here is applicable to the case where the PSFCH covers the entire frequency range F, and is also applicable to the PSFCH covering a subset of the frequency range F used for original data transmission (for example, the frequency range F In the case of a subset of RB).

In one example, ACK/NACK feedback can be transmitted using a sequence. For example, sequence 1 transmission can indicate ACK, while sequence 2 transmission can indicate NACK. The sequence may include, for example, Lm coefficients, where m is the number of subcarriers in the RB. In this case, the sequence can be mapped to the entire frequency range F=[F1 to F2], or to a subset of the frequency range F. In an example, the position of the PSFCH in the frequency resource F may be fixed. For example, the feedback may always be transmitted in the first RB of the allocation F. In an example, the position of the PSFCH in the frequency resource may be based on other transmissions such as UE ID (for example, mod (UE2 ID, the number of RBs in the frequency resource) may indicate the index of the first RB of the PSFCH). parameter.

In one example, the ACK/NACK bits can be encoded and modulated to create a feedback transport block that can be mapped to subcarriers in the available frequency resource range F. The index of the RB used to transmit the feedback block may be predetermined or may be a function of other transmission parameters such as UE ID. In one example, ACK/NACK feedback can be mapped to a subset of the available frequency range F, and the remaining subcarriers in F can be used to transmit other control information, such as CSI. For example, if F includes N RBs, UE 2 may use m RBs to transmit ACK/NACK to UE 1, and UE 2 may use the remaining Nm RBs to transmit CSI to UE 1. In this case, ACK/NACK and CSI can be coded separately. CSI transmission may be requested within DCI (for example, aperiodic CSI) or may be configured for transmission using predetermined time and/or frequency resources. In one example, if the WTRU is not scheduled to transmit CSI but has ACK/NACK to transmit, it can use the remaining resources in frequency range F to transmit data.

In one example, if the traffic type is multicast and feedback is required, the multiple receiving WTRUs can return ACK/NACK in the same PSFCH. In one example, these WTRUs implement time division and/or frequency division and/or code division multiplexing to multiplex their ACK/NACK bits. At least one resource used for feedback (for example, the index of the OFDM symbol and the subcarrier, the index of the cyclic shift of the sequence, the index of the spreading sequence) may be a function of the UE ID to prevent collisions. In an example, the PSFCH may include complex OFDM symbols. FIG. 16 shows a resource diagram of another exemplary time slot format 1600, where the PSFCH 1610 (transmitted from WTRU 1602 to WTRU 1601) in the frequency range [F1, F2] includes complex OFDM symbols. In one example, at least a part of an OFDM symbol may be used for automatic gain control (AGC) purposes at the receiver.

In an example, the same complex symbols are repeated in all OFDM symbols of the PSFCH, for example, to reduce or avoid performance loss. The complex symbols can be sequence and/or coded and modulated data bits and/or DMRS symbols. In one example, the first OFDM symbol is used to transmit a known sequence, such as a DMRS sequence, to reduce or avoid performance loss. In one example, the complex data bits are encoded, rate matched, and modulated, so that all subcarriers on all OFDM symbols are used to map the modulated symbols, for example, to reduce or avoid performance loss.

In one example, the reservation and preemption of V2X can be performed with or without IAB. In one example, the WTRU may transmit a reservation signal to reserve transmission resources. The reserved signal may include coded bits and may be used to notify the listening WTRU of the resources that the transmitting WTRU plans to reserve for its own transmission at a later time. In an example, the reservation signal can be used to reserve resources for the SA and data transmission. For example, the reserved signal may be transmitted on a subset of the frequency resources expected to be used for the planned SA transmission. FIG. 17 shows a resource diagram of another exemplary time slot format 1700, in which two samples are taken for the frequency resources 1710, 1714 in which the reserved signals 1706, 1708 can be transmitted. The WTRU may transmit the reservation signal 1706, 1708 on a set of frequency resources 1710, 1714 in time slot n . In one example, the reserved signals 1706, 1708 can be transmitted on one or more OFDM symbols in time slot n . This reserved signal is used to reserve frequency resources in time slots [ n+k ] to [ n+k+L ]. Note that L can be non-zero or zero. The resource relationship between the reserved signals 1706, 1708 and the SA 1712, 1716 may cause the reserved signals 1706, 1708 to be transmitted in one of the PDCCH candidates of the CORESET configured for the SA 1712, 1716. In this case, a single CORESET configuration for SA 1712, 1716 and reserved signals 1706, 1708 can be used. In an example, a separate CORESET can be configured for the reserved signal, where the reserved signal CORESET can be a subset of the SA CORESET. Note that k can be zero, so that the reserved signal and the associated SA/data transmission can occur in the same time slot. In this case, the reserved signal, the SA, and the data transmission can share the reserved frequency resources.

In one example, the CORESET of the reserved signal can be separated from the CORESET of the SA. In this case, the control information transmitted in the reservation signal may include the frequency and/or time resources to be reserved. In the example, the time resource to be reserved can be determined from the time resource of the reserved signal. For example, the difference between the first time slot index of the reserved resource and the time slot index of the reserved signal may be fixed, for example, k time slots. The cyclic redundancy check (CRC) of the reserved signal can be scrambled with a specific RNTI (for example, reserved RNTI). The WTRU that intends to initiate the transmission can detect and decode the reserved signal and create a mapping of the reserved resources.

In one example, the preempt signal can be used to overwrite the previously transmitted reserved signal. For example, the first WTRU may transmit a reservation signal to allocate resources. The second WTRU may rewrite the allocation by transmitting a preempt signal. The second WTRU may have a higher priority than the first WTRU. In an example, the preempt signal and the overwritten reservation signal may be associated with each other. The preemption signal can be transmitted on the same control channel frequency resource as the reserved signal. There may be a fixed timing relationship between the time slot for transmitting the preempt signal and the time slot for which the resource has been scheduled.

In one example, the preempt signal may be transmitted in different PDCCH candidates within the same CORESET of the reserved signal or in different CORESETs. The preemption signal may carry time/frequency resources of the preempted resource. The preemptive signal may be CRC scrambled using a separate RNTI (for example, preemptive RNTI). In one example, both the reserved signal and the preempt signal can use the same format and RNTI. In one example, the DCI content can (for example, use bits/flags) to indicate whether it is a reserved signal or a preemptive signal. FIG. 18 shows a resource diagram of another exemplary time slot format 1800 including reserved signals 1806 and 1808 and preempt signals 1810 and 1812. In this example, the first WTRU transmits reservation signals 1806, 1808 in time slot n to reserve resources for SA 1816, 1820, and data transmission starting from time slot n+k. The second WTRU transmits preemption signals 1810, 1812 in time slot n+m to overwrite the reservation of the first WTRU. The first WTRU may exclude previously reserved resources from availability after receiving the preemption signals 1810, 1812. In an example, the subset of available resources can include preemptable attributes, and can preempt those resources. In one example, a WTRU that reserves those resources may need to decode all possible preempt signals.

In one example, the preemptable resource can be preempted in the same time slot when the SA and data transfer are planned. FIG. 19 shows a resource map of another exemplary time slot format 1900 including a low-latency time preemptive scene. In this example, the first WTRU receives at least the first OFDM symbol in the current time slot. The first WTRU searches for a preempt signal 1906 in at least the first OFDM symbol. If the first WTRU detects a preempt signal 1906 that reserves the current time slot for another WTRU, the first WTRU aborts and does not use the current time slot for transmission. If the first WTRU does not detect the preempt signal, it stops receiving and turns on its transmitter. The Rx/Tx turnaround time 1910 may take less than one OFDM symbol, one OFDM symbol, or more than one OFDM symbol. When the transmitter is turned on and ready, the first WTRU starts transmitting its own SA and/or data in the remainder of the time slot. From the perspective of the first WTRU, since the initial part of the time slot cannot be used for transmission, the first WTRU may accordingly puncture the prepared transmission block (TB) to compensate for unavailable resources.

In one example, when the time slot includes possible ACK/NACK transmissions from the first WTRU, the preemption may only affect a part of the time slot. If the preemptive WTRU is aware of the ACK/NACK transmission, the resources allocated by the first WTRU for the ACK/NACK transmission may be skipped by another WTRU. The information about whether reserved resources will be used for ACK/NACK transmission may be part of the reserved signal. For example, the flag in the reserved signal may indicate that the reserved resources may (e.g., partially) be used for ACK/NACK feedback. In an example, the reserved signal may indicate the OFDM symbol allocated for the ACK/NACK feedback. In this case, the WTRU that preempts the reservation may allow the reserved WTRU to transmit the feedback information.

Although the features and elements of the present invention are described in specific combinations in the preferred embodiments, each feature or element can be used alone without the other features and elements of the preferred embodiment, or with or without the present invention. The other features and elements of the invention are used in various combinations.

Although the solution described herein considers LTE, LTE-A, New Radio (NR), or 5G specific agreements, it should be understood that the solution described herein is not limited to this situation and can also be applied to other wireless systems.

Although the features and elements are described above in specific combinations, those 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. In addition, the methods described herein can be implemented in a computer program, software or firmware incorporated in a computer-readable medium to be executed by a computer or a processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted through wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, buffer memory, semiconductor memory devices, magnetic media (for example, internal hard drives and removable Magnetic disk), magneto-optical media, and optical media (for example, CD-ROM discs and digital versatile discs (DVD)). The processor associated with the software can be used to implement the radio frequency transceiver for the WTRU, UE, terminal, base station, RNC, and any host computer.

100: Communication system 102, 102a, 102b, 102c, 102d, 212 _A -212 _C , 302, 402 ₁ -402 ₄ , 702, 802, 804, 902, 904: wireless transmission/reception unit (WTRU) 104: radio storage Access Network (RAN) 106: Core Network (CN) 108: Public Switched Telephone Network (PSTN) 110: Internet 112: Other Networks 114a, 114b, 304: Base Station 116: Air Interface 118: Processor 120: Transceiver 122: Transmit/receive element 124: Speaker/Microphone 126: Keypad 128: Display/Touchpad 130: Non-removable memory 132: Removable memory 134: Power supply 136: Global Positioning System (GPS) Chipset 138: Peripherals 160a, 160b, 160c: eNodeB 162: Mobility Management Entity (MME) 164: Service Gateway 166: Packet Data Network (PDN) Gateway 180a, 180b, 180c, 704, 806, 906: gNB 182a, 182b: Access and Mobility Management Function (AMF) 183a, 183b: Session Management Function (SMF) 184a, 184b: User Plane Function (UPF) 185a, 185b: Data Network (DN) 200: New radio (NR) network deployment 204: Backhaul link 206 _A- 206 _C : Relay transmission receiving point 208: Optical fiber transmission backhaul link 210: Multiple access link 300: Side link WTRU information exchange program 306 : The system block (SIB) type 21 (SIB21) 308: side link information WTRU 310: RRC connection reconfiguration message 400: PRACH configuration _4061-4064, 502: integration access and backhaul (IAB) nodes 410, 412: Periodic period 430: Exemplary schedule 500: Synchronization signal block (SSB) configuration 600: SSB subset assignment procedure for latency reduction 700: RACH message exchange 706, 708, 710: Msg 1 712, 714: Random storage Get response (RAR) 716, 718: Msg 3 720: Msg 4 722: Msg3 retransmission 800, 900: IAB network deployment 801, 901: RACH message exchange 812, 820, 822, 912: High-speed uplink (UL) data 813, 811, 821, 825, 911, 913: first listen and wait (LBT) 816, 916: preamble transmission 823, 915: protection period 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 : Time slot format 1420, 1424: Frequency resource 1508, 1710, 1714, 18 14, 1818: physical side link shared channel (PSSCH) 1706, 1708, 1806, 1808: reserved signal 1712, 1716, 1816, 1820: scheduled assignment (SA) 1810, 1812, 1906: preempt signal HARQ: hybrid automatic repeat Request Msg: Message PRACH: Physical Random Access Channel PSFCH: Physical Side Link Feedback Channel RACH: Not Received Before the End of the RAR Window RO: RACH Timing RRC: Radio Resource Control WTRU: Wireless Transmission/Receiving Unit

In addition, the same element symbols in the drawings represent the same elements, and among them: FIG. 1A is a system diagram showing an exemplary communication system in which one or more disclosed embodiments can be implemented; FIG. 1B is a system diagram showing an exemplary wireless transmission/reception unit (WTRU) that can be used in the communication system shown in FIG. 1A according to an embodiment; 1C is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that can be used in the communication system shown in FIG. 1A according to an embodiment; FIG. 1D is a system diagram showing another exemplary RAN and another exemplary CN that can be used in the communication system shown in FIG. 1A according to an embodiment; Figure 2 shows an exemplary new radio (NR) network deployment with integrated access and backhaul (IAB) links; Figure 3 is a signaling diagram of an exemplary side-link WTRU information exchange procedure for communication between a (vehicle) WTRU and a base station for vehicle-to-everything (V2X) side-link transmission; Figure 4 shows an exemplary physical random access channel (PRACH) configuration in an exemplary NR IAB network deployment; Figure 5 shows a subset of the synchronization signal block (SSB) broadcast within the PRACH configuration; Figure 6 shows the SSB subset method for latent time reduction; Figure 7 shows an exemplary RACH message exchange between a WTRU and a gNB, which can be used for unauthorized operations in the IAB system; Figure 8A shows an exemplary IAB network deployment; FIG. 8B shows a transmission diagram of an exemplary RACH message exchange according to the exemplary transmission timing of the exemplary IAB network deployment in FIG. 8A; FIG. 8C shows a signaling diagram of another exemplary RACH message exchange according to another exemplary transmission timing of the exemplary IAB network deployment in FIG. 8A; Figure 9A shows an exemplary IAB network deployment, in which two WTRUs are positioned close to each other and at the boundary of the same cell; FIG. 9B shows a transmission diagram of an exemplary RACH message exchange according to the exemplary transmission timing of the exemplary IAB network deployment in FIG. 9A; FIG. 10 shows a resource diagram in an exemplary time slot format, in which feedback resources are derived from resources used for data transmission; Figure 11 shows another exemplary resource diagram in a time slot format, in which feedback resources are derived from resources used for data transmission; FIG. 12 shows a resource diagram of another exemplary time slot format 1200, in which the feedback resource 1222 is derived from the resource 1220 used for data transmission; FIG. 13 shows a resource diagram of an exemplary time slot format including two scheduled assignment (SA) phases (SA phase-1 and SA phase-2); Figure 14 shows a resource diagram in an exemplary time slot format, in which feedback resources are derived from resources used for data transmission; Figure 15 shows a resource diagram in an exemplary time slot format, in which feedback resources are derived from resources used for data transmission; FIG. 16 shows a resource diagram of another exemplary time slot format, where the physical side link feedback channel (PSFCH) includes a complex number of OFDM symbols; FIG. 17 shows a resource diagram of another exemplary time slot format, in which two samples are taken for the frequency resources in which reserved signals can be transmitted; FIG. 18 shows a resource diagram of another exemplary time slot format including a reserved signal and a preempt signal; and FIG. 19 shows a resource diagram in another exemplary time slot format including a low-latency time preemption scenario.

1400: Time slot format

1420, 1424: frequency resources

HARQ: Hybrid automatic repeat request

PSSCH: physical side link shared channel

WTRU: wireless transmission/reception unit

Claims (20)

A first wireless transmission/reception unit (WTRU), including: A receiver A transmitter; and A processor, where The receiver is configured to: for a signal from a second WTRU, monitor a first frequency resource including a first complex resource block (RB) and having a first frequency range in a first time slot, wherein the The first frequency resource is associated with a physical side link shared channel (PSSCH) of the second WTRU; The processor is configured to determine a feedback frequency resource based on at least one of the first frequency range, a number of RBs in the first plurality of RBs, or an identification code of the first WTRU; and The transmitter is configured to use the feedback frequency resource to transmit feedback information to the second WTRU in a second time slot. The first WTRU according to claim 1, wherein the feedback frequency resource is a hybrid automatic repeat request (HARQ) frequency resource, and the feedback transmitted using the feedback frequency resource is a HARQ feedback. The first WTRU according to claim 1, wherein the feedback frequency resource includes at least a subset of the first complex RB. The first WTRU according to claim 1, wherein the feedback frequency resource is in the first frequency range. The first WTRU according to claim 1, wherein a second frequency range is within the first frequency range and is associated with a physical side link control channel (PSCCH) of the second WTRU, and the feedback frequency resource Is in this second frequency range. The first WTRU according to claim 1, wherein the feedback frequency resource is associated with a physical side link feedback channel (PSFCH) of the first WTRU. The first WTRU according to claim 1, wherein the feedback information is one of the following: a hybrid automatic repeat request (HARQ) feedback information; an ACK/NACK information; or a channel status information (CSI). The first WTRU according to claim 1, wherein the first frequency range includes the complex number of subcarriers in the first time slot and the complex number of subcarriers in the second time slot. The first WTRU of claim 1, wherein the first frequency range includes a complex number of OFDM symbols in the first time slot and the complex number of OFDM symbols in the second time slot. The first WTRU described in claim 1, which is configured for a vehicle-to-vehicle (V2X) communication. A method executed by a first wireless transmission/reception unit (WTRU), the method includes: For a signal from a second WTRU, a first frequency resource including a first complex resource block (RB) and having a first frequency range is monitored in a first time slot, wherein the first frequency resource and the second frequency resource are Two WTRUs are associated with a physical side link shared channel (PSSCH); Determining a feedback frequency resource based on at least one of the first frequency range, a number of RBs in the first complex number of RBs, or an identification code of the first WTRU; and The feedback frequency resource is used in a second time slot to send feedback information to the second WTRU. The method according to claim 11, wherein the feedback frequency resource is a hybrid automatic repeat request (HARQ) frequency resource, and the feedback transmitted using the feedback frequency resource is a HARQ feedback. The method according to claim 11, wherein the feedback frequency resource includes at least a subset of the first complex number RB. The method according to claim 11, wherein the feedback frequency resource is in the first frequency range. The method according to claim 11, wherein a second frequency range is within the first frequency range and is associated with a physical side link control channel (PSCCH) of the second WTRU, and the feedback frequency resource is in In the second frequency range. The method of claim 11, wherein the feedback frequency resource is associated with a physical side link feedback channel (PSFCH) of the first WTRU. The method according to claim 11, wherein the feedback information is one of the following: a hybrid automatic repeat request (HARQ) feedback information; an ACK/NACK information; or a channel status information (CSI). The method according to claim 11, wherein the first frequency range includes a complex number of subcarriers in the first time slot and the complex number of subcarriers in the second time slot. The method according to claim 11, wherein the first frequency range includes a complex number of OFDM symbols in the first time slot and the complex number of OFDM symbols in the second time slot. The method of claim 11, wherein the first WTRU is configured for a vehicle-to-vehicle (V2X) communication.

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