System and method for device-to-device communication

Abstract

The present disclosure relates to systems, apparatus, methods, and non-transitory computer readable media for performing, by a first wireless communication device, a channel access procedure for at least one channel and communicating, by the first wireless communication device, an SL positioning related transmission with a second wireless communication device using the at least one channel, the SL positioning related transmission includes at least one of an SL positioning reference signal (SL-PRS) or a physical shared control channel (PSCCH) corresponding to the SL-PRS.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to wireless communications, and more specifically to device-to-device communications. BACKGROUND

[0002] Sidelink (SL) communication refers to radio communication between two or more user equipments (UEs). In this type of communication, two or more UEs that are geographically close to each other can communicate without being routed to a network (e.g., a base station (BS)) or a core network. Thus, data transmission in SL communication is different from typical cellular network communication that includes transmission of data to and reception of data from a BS. In SL communication, data is transmitted directly from a source UE to a target UE through, for example, a unified air interface (e.g., a PC5 interface) without passing through a BS.

[0003] In a conventional SL positioning mechanism, a target requirement of sub-meter accuracy (Group B) cannot be achieved. SL positioning reference signal (PRS) bandwidth is critical for positioning accuracy. For example, for SL positioning in frequency range 1 (FR1), a maximum of 100 MHz is recommended. However, currently only intelligent transport system (ITS) bands and licensed spectrum in FR1 support Rel-18 SL positioning. The available bandwidth resource of ITS and FR1 is less than 40 MHz. SUMMARY

[0004] The example embodiments disclosed herein are intended to address problems related to one or more of the problems set forth in the prior art, and additional features that will be apparent to those of ordinary skill in the art in view of the following detailed description, when taken in conjunction with the drawings. In accordance with various embodiments, example systems, methods, apparatus and computer program products are disclosed herein. It should be understood, however, that these embodiments are given by way of example only and that various modifications can be made by those skilled in the art to the disclosed embodiments, e.g., incorporating features from various disclosed examples, embodiments and / or implementations, while still falling within the scope of the present disclosure.

[0005] Some embodiments of the disclosure relate to systems, methods, apparatuses, and non-transitory computer-readable media, a first wireless communication device performs a channel access procedure of at least one channel and the first wireless communication device transmits SL positioning related transmissions with a second wireless communication device using the at least one channel, where the SL positioning related transmissions include at least one of a SL positioning reference signal (SL-PRS) or a physical shared control channel (PSCCH) corresponding to the SL-PRS.

[0006] The above and other aspects and implementations thereof are described in more detail in the accompanying drawings, description, and claims. BRIEF DESCRIPTION OF DRAWINGS

[0007] Various example embodiments of the present solution are described in detail below with reference to the following drawings. The provided drawings or diagrams are for illustration only and only depict example embodiments of the present solution to facilitate understanding of the present solution by those skilled in the art. Thus, the drawings should not be considered to be limiting of the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

[0008] Figure 1A is a schematic diagram of an exemplary wireless communication system shown in accordance with various embodiments.

[0009] Figure 1A is a block diagram of an exemplary wireless communication system shown in accordance with various embodiments that transmits and receives downlink, uplink, and / or SL communication signals.

[0010] Figure 2 is an exemplary scenario of SL communication shown in accordance with various embodiments.

[0011] Figure 3 is a schematic diagram of candidate resource selection for transmitting SL-PRS shown in accordance with various embodiments.

[0012] Figure 4 is a flow diagram of an exemplary method of transmitting SL positioning related transmissions shown in accordance with various embodiments.

[0013] Figure 5 is a CAPC table shown in accordance with various embodiments.

[0014] Figure 6 is a signaling diagram of an exemplary method of determining SL pathloss based on power control shown in accordance with various embodiments.

[0015] Figure 7 is a signaling diagram of an exemplary method of adjusting a CW based on measurement result feedback shown in accordance with various embodiments.

[0016] Figure 8 is a diagram of an exemplary Type 2 channel access procedure for SL positioning transmissions used in COT sharing scenarios according to various embodiments.

[0017] Figure 9 is a diagram of one COT shared by different responding UEs according to various embodiments.

[0018] Figure 10 is a signaling diagram of an exemplary method of COT sharing in SL-RTT positioning according to various embodiments.

[0019] Figure 11 is a diagram of exemplary COT sharing within a group according to various embodiments.

[0020] Figure 12 is a diagram of exemplary gNB-to-UE COT sharing in an NRU according to various embodiments.

[0021] Figure 13 is a diagram of an exemplary gNB-to-UE COT sharing in SL-U positioning according to various embodiments.

[0022] Figure 14 is a diagram of an example of a gNB scheduling SL-PRS transmissions of different UEs within one COT according to various embodiments.

[0023] Figure 15 is a diagram of an example of UE-to-gNB COT sharing in SL-U positioning according to various embodiments.

[0024] Figure 16 is a diagram of a relationship between a bandwidth and a set of RBs of a dedicated resource pool according to various embodiments.

[0025] Figure 17 is an exemplary ServingCellConfig according to various embodiments.

[0026] Figure 18 is a diagram of semi-static channel access according to various embodiments.

[0027] Figure 19 is a diagram of semi-static channel access for two UEs according to various embodiments. DETAILED DESCRIPTION

[0028] Various example implementations of the present solution are described below with reference to the accompanying drawings, so as to enable ordinary skilled in the art to make and use the present solution. As will be apparent to those of ordinary skill in the art after reading this disclosure, various changes or modifications to the example described herein can be made without departing from the scope of the present solution. Thus, the present solution is not limited to the example implementations and applications described and illustrated herein. Additionally, the particular order or hierarchy of steps in the methods disclosed herein are merely examples. The specific order or hierarchy of steps disclosed can be re-arranged, and the particular order or hierarchy of steps can be re-implemented, without departing from the scope of the present solution. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein are presented for sample orders and hierarchies of steps, and that the present solution is not limited to the specific order or hierarchy presented. The steps or actions in the methods presented can be re-ordered or re-arranged without departing from the scope of the present solution. It is understood that each feature provided in the example described herein can be replaced by alternative features serving the same, equivalent or a similar purpose without departing from the scope of the present solution. Therefore, the foregoing description and drawings are by way of example only, and the present solution is not limited to the example implementations described and illustrated herein.

[0029] With the emergence of wireless multimedia services, users' demand for high data rates and user experience is increasing, which puts higher requirements on the system capacity and coverage of traditional cellular networks. In addition, public safety, social networks, close-range data sharing and local advertising gradually expand the demand for proximity services, which allow users to learn about and communicate with nearby users or objects. Traditional network-centric cellular networks have limitations in terms of high data rates and supporting proximity services. In this context, Device-to-Device (D2D) communication has emerged to address the shortcomings of the network-centric model. The application of D2D technology can alleviate the burden of the cellular network, reduce the battery power consumption of the UE, improve the data rate, and improve the robustness of the network infrastructure, thereby meeting the above-mentioned demand for high data rate services and proximity services. D2D technology is also known as Proximity Services (ProSe), one-way / side link / SL communication, etc.

[0030] In some implementations, wireless communication can be conducted over carriers, bands, and / or spectrums. Some carriers are licensed carriers because a government or another authority entity licenses these carriers to be used exclusively by a service provider. Some carriers are unlicensed carriers that do not have exclusive licenses from any government or authority entity. Two or more service providers can operate in unlicensed carriers. Currently, UEs can directly communicate with each other over licensed carriers (e.g., without using a base station to do so). There is no solution for UEs to communicate with each other over unlicensed carriers.

[0031] In some implementations, a licensed carrier refers to a carrier, band, or spectrum that is licensed by a government or authority (e.g., the Federal Communications Commission (FCC) in the United States and the European Telecommunications Standards Institute (ETSI) in Europe) to a service provider exclusively. An unlicensed carrier (or shared spectrum) refers to a carrier, band, or spectrum that is not licensed by a government or other authority. Two or more service providers can operate in an unlicensed carrier.

[0032] Embodiments disclosed in this example relate to SL positioning in unlicensed bands (shared spectrum), including channel access procedures and channel design. This example describes signaling procedures for sidelink positioning.

[0033] Reference Figure 1A An example wireless communication system 100 is shown in FIG. 1. The wireless communication system 100 enables group communication within a cellular network. In the wireless communication system, network-side communication nodes or networks can include a Generation Node B (gNB), an E-UTRAN Node B (also referred to as an evolved Node B, eNodeB, or eNB), a pico station, a femto station, a Transmission / Reception Point (TRP), an Access Point (AP), and the like. Terminal-side nodes or UEs can include devices such as mobile devices, smartphones, cellular phones, Personal Digital Assistants (PDAs), tablet computers, laptop computers, wearable devices, vehicles with onboard communication systems, and the like. In some examples, a UE can be a vehicle UE, a pedestrian UE, a Road-Side UE (RSU), a Positioning Reference Unit (PRU), and the like. The UEs described in this example can implement the methods described in this example with or without a known location. In some examples, the UEs described in this example can be implemented as a network-side communication node or a terminal-side communication node. Figure 1A In FIG. 1, network-side and terminal-side communication nodes are represented by the network 102 and the UEs 104a and 104b, respectively. In some implementations, the network and the UEs 104a / 104b are sometimes referred to as “wireless communication nodes” and “wireless communication devices,” respectively. Such communication nodes / devices can perform wireless communication.

[0034] In Figure 1AIn the illustrated implementation, the network 102 can define a cell 101 in which the UEs 104a and 104b are located. The UEs 104a and / or 104b can move within the coverage of the cell 101 or remain stationary. The UE 104a can communicate with the network 102 via a communication channel 103a. Similarly, the UE 104b can communicate with the network 102 via a communication channel 103b. In addition, the UEs 104a and 104b can communicate with each other via a communication channel 105. The communication channels 103a and 104b between the respective UEs and the BS can be implemented using an interface such as a Uu interface, which is also referred to as a Universal Mobile Telecommunication System (UMTS) air interface. The communication channel 105 between the UEs is a SL communication channel and can be implemented using a PC5 interface, which is introduced to address high mobility speed and high density applications such as D2D communication, Vehicle-to-Vehicle (V2V) communication, Vehicle-to-Pedestrian (V2P) communication, Vehicle-to-Infrastructure (V2I) communication, Vehicle-to-Network (V2N) communication, and the like. In some cases, the vehicle network communication modes can be collectively referred to as Vehicle-to-Everything (V2X) communication. The network 102 is connected to a Core Network (CN) 108 through an external interface 107 (e.g., an Iu interface).

[0035] In some examples, a remote UE (e.g., UE 104b) that does not directly communicate with the network 102 or the CN 108 (e.g., communication channel link 103b is not established) indirectly communicates with the network 102 and the CN 108 via a relay UE (e.g., UE 104a) using the SL communication channel 105, which can directly communicate with the network 102 and the CN 108 or indirectly communicate with the network 102 and the CN 108 via another relay UE that can directly communicate with the network 102 and the CN 108.

[0036] Figure 1B A block diagram of an exemplary wireless communication system for transmitting and receiving downlink, uplink, and SL communication signals is shown in accordance with various implementations. In some implementations, the system can transmit and receive data in a wireless communication environment (e.g., a wireless communication system 100) as described above. Figure 1A

[0037] As Figure 1A ​The system, as shown, generally includes a network 102 and UEs 104a and 104b. The network 102 includes a network transceiver module 110, a network antenna 112, a network memory module 116, a network processor module 114, and a network communication module 118, each coupled and interconnected to each other via a data communication bus 120 as necessary. The UE 104a includes a UE transceiver module 130a, a UE antenna 132a, a UE memory module 134a, and a UE processor module 136a, each coupled and interconnected to each other via a data communication bus 140a as necessary. Similarly, the UE 104b includes a UE transceiver module 130b, a UE antenna 132b, a UE memory module 134b, and a UE processor module 136b, each coupled and interconnected to each other via a data communication bus 140b as necessary. The network 102 communicates with the UEs 104a and 104b via one or more communication channels 150, which can be any wireless channel or other medium known in the art suitable for data transmission as described in the present example.

[0038] In addition to the modules shown, the system can include any number of modules. Those of skill in the art will appreciate that the various illustrative blocks, modules, circuits, and processing logic described in connection with the implementations disclosed herein can be implemented in hardware, computer readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality, where the Figure 1B In addition to the modules shown, the system can include any number of modules. Those of skill in the art will appreciate that the various illustrative blocks, modules, circuits, and processing logic described in connection with the implementations disclosed herein can be implemented in hardware, computer readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality, where the

[0039] Wireless transmissions from an antenna of one of the UEs 104a and 104b to an antenna of the network 102 are referred to as uplink transmissions, and wireless transmissions from an antenna of the network 102 to an antenna of one of the UEs 104a and 104b are referred to as downlink transmissions. According to some embodiments, each of the UE transceiver modules 130a and 130b can be referred to as an uplink transceiver or UE transceiver in this example. The uplink transceiver can include transmitter and receiver circuitry, both coupled to respective antennas 132a and 132b. Alternatively, a duplex switch can couple the uplink transmitter or receiver to the uplink antenna in a time-division duplex manner. Similarly, the network transceiver module 110 can be referred to as a downlink transceiver or network transceiver in this example. The downlink transceiver can include RF transmitter and receiver circuitry, both coupled to the antenna 112. A downlink duplex switch can couple the downlink transmitter or receiver to the antenna 112 in a time-division duplex manner. The operations of the transceivers 110 and 130a and 130b are coordinated in time such that the uplink receiver is coupled to the antennas 132a and 132b for receiving transmissions on the wireless communication channel 150 at the same time that the downlink transmitter is coupled to the antenna 112. In some embodiments, the UEs 104a and 104b can communicate with the network 102 via the wireless communication channel 150 using the UE transceivers 130a and 130b through the respective antennas 132a and 132b. The wireless communication channel 150 can be any wireless channel or other medium suitable for downlink and / or uplink data transmission as described in this example, as known in the art. The UEs 104a and 104b can communicate with each other via the wireless communication channel 170. The wireless communication channel 170 can be any wireless channel or other medium suitable for SL transmission of data as described in this example.

[0040] Each of the UE transceivers 130a and 130b and the network transceiver 110 are configured to communicate via the wireless data communication channel 150 and cooperate with appropriately configured antenna arrangements capable of supporting a particular wireless communication protocol and modulation scheme. In some embodiments, the UE transceivers 130a and 130b and the network transceiver 110 are configured to support industry standards, for example, Long Term Evolution (LTE) and emerging 5G and 6G standards, etc. However, it should be understood that the present disclosure need not be limited in its application to a particular standard and related protocols. Rather, the UE transceivers 130a and 130b and the network transceiver 110 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0041] The processor modules 136a and 136b and 114 can each be implemented or realized with a general purpose processor, a content addressable memory, a digital signal processor, a application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. In this manner, the processor can be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. The processor can also be implemented as a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.

[0042] Furthermore, the methods and algorithms described in connection with the embodiments disclosed herein can be embodied directly in hardware, firmware, software modules executed by processor modules 114 and 136a and 136b, respectively, or any actual combination thereof. The memory modules 116 and 134a and 134b can be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 116 and 134a and 134b can be coupled to the processor modules 114 and 136a and 136b, respectively, such that the processor modules 114 and 136a and 136b can read information from, and write information to, the memory modules 116 and 116. The memory modules 116, 134a and 134b can also be integrated into their respective processor modules 114, 136a and 136b. In some embodiments, the memory modules 116, 134a and 134b can each include a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor modules 116, 134a and 136b, respectively. The memory modules 116, 134a and 134b can also each include non-volatile memory for storing instructions to be executed by the processor modules 114 and 136a and 136b, respectively.

[0043] Network interface 118 typically represents hardware, software, firmware, processing logic, and / or other components of network 102 that enable bidirectional communication between network transceiver 110 and other network components and communication nodes configured to communicate with network 102. For example, network interface 118 may be configured to support Internet or WiMAX traffic. In a non-limiting typical deployment, network interface 118 provides an 802.3 Ethernet interface, allowing network transceiver 110 to communicate with traditional Ethernet-based computer networks. In this way, network interface 118 may include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). The terms "configured for" or "configured to" used in this example for a particular operation or function refer to devices, components, circuits, structures, machines, signals, etc., that are physically constructed, programmed, formatted, and / or implemented to perform the specified operation or function. Network interface 118 may allow network 102 to communicate with other networks or core networks via wired or wireless connections.

[0044] In some implementations, each of UEs 104a and 104b can operate in a hybrid communication network in which the UE communicates with network 102 and with other UEs, for example, between 104a and 104b. As described in further detail below, UEs 104a and 104b support SSL communication with other UEs as well as downlink / uplink communication between network 102 and UEs 104a and 104b. Typically, SSL communication allows UEs 104a and 104b to establish direct communication links with each other or with other UEs from different cells without requiring network 102 to relay data between UEs.

[0045] Figure 2 This is a schematic diagram of an exemplary SL communication system according to various embodiments. For example... Figure 2 As shown, network 210 (e.g., Figure 1A Network 102) broadcasts signals received by the first UE 220, the second UE 230 and the third UE 240. Figure 2 UEs 220 and 230 are shown as vehicles with a vehicle communication network, while UE 240 is shown as a mobile device. As shown in SL, UEs 220-240 are able to communicate with each other via an air interface (e.g., direct transmission and reception) without being forwarded by base station 210 or core network 250. This type of V2X communication is referred to as PC5-based V2X communication or V2X SL communication.

[0046] As used in this example, when two UEs 104a or 104b communicate with each other via a communication channel 105 / 170, the UE transmitting data to the other UE is referred to as the transmitting (TX or Tx) UE, and the UE receiving the data is referred to as the receiving (RX or Rx) UE.

[0047] In some examples, for licensed band or in-band SL positioning / ranging, both scheme 1 resource allocation and scheme 2 resource allocation are supported. Scheme 1 resource allocation can also be considered as network-centric operation and SL-PRS resource allocation, where a BS (e.g., gNB) configures / schedules the SL-PRS resources to be transmitted via dynamic grant, configured grant type 1, or configured grant type 2. Scheme 2 is a UE autonomous SL-PRS resource allocation mode, where the SL-PRS resources to be transmitted are based on any one / two of sensing results, Inter-UE Coordination (IUC) information, or / and random resource selection.

[0048] In 5G New Radio-Unlicensed (NR-U) or SL-Unlicensed (SL-U), the main restriction for using shared or unlicensed spectrum is that a device, including a BS, a UE, or other non-3GPP users (e.g., WIFI devices), can only access the channel after a Listen Before Talk (LBT) succeeds or a Clear Channel Assessment (CCA) result shows that the channel is idle. In some cases, the channel access procedure is a sensing-based procedure that assesses the availability of the channel for performing a transmission.

[0049] FR1 NR-U includes two CCA modes. The first CCA mode includes a Load-Based Equipment (LBE) or dynamic channel access mode. Type 1 includes a CCA time before a transmission is random, and Type 2 includes a CCA time before a transmission is deterministic. Type 2 further includes Type 2A, Type 2B, and Type 2C. There is a difference between DL channel access and UL channel access, for example, the Channel Access Priority Class (CAPC) table for DL Type 1 channel access and Type 1 UL channel access is different.

[0050] The second CCA mode includes a Frame-Based Equipment (FBE) or semi-static channel access mode, in which the time domain resources for FBE mode are periodic. One fixed frame period (FFP) includes a channel occupancy time (COT) and an idle period. The idle period is located at the end of the FFP.

[0051] In some embodiments, the UE performs a channel access scheme, referred to as LBT, before performing data transmission on the unlicensed carrier. In the LBT procedure, the UE monitors the channel in the unlicensed carrier for a time interval. In response to determining that the LBT procedure is successful, the UE can occupy the channel in the unlicensed carrier for a time interval referred to as COT. The LBT procedure includes an initial LBT procedure and a non-initial LBT procedure. The non-initial LBT procedure is conducted within the COT.

[0052] In some embodiments, the CAPC table described in this embodiment is used for Type 1 channel access. For example, the CAPC table defines the association between CAPC (p) and {m p , CW min,p , CW max,p , T mcot,p , allowed CW p size}. In some examples, m p refers to the deferral duration T d , which includes the duration T f = 16 μs immediately after the m p consecutive sensing slot duration T sl . T f includes the idle sensing slot duration T f at the beginning of T sl . For CW min,p , CW max,p , allowed CW p size, CW p is the size of the contention window (CW), where CW min,p ≤ CW p ≤ CW max,p . Based on the allowed CW p size associated with the CAPC p, the CW p adjustment for DL / UL channel access and SL channel access for communication is supported. Regarding T mcot,p , the UE or BS (e.g., eNB or gNB) does not transmit on the channel beyond the COT of T mcot,p , where the channel access procedure is performed based on the CAPC p associated with the transmission of the UE or BS.

[0053] A channel in NR-U or SL-U refers to a carrier or a portion of a carrier that includes a contiguous set of frequency domain resources (e.g., Resource Blocks (RBs)) on which a channel access procedure is performed in a shared spectrum. In some examples, one channel is associated with one RB set. In examples where a wide bandwidth is requested for service (e.g., including two or more RB sets), a multi-channel access procedure is applied by the device. DL Type A and Type B multi-channel access procedures as well as UL multi-channel access procedures can be implemented.

[0054] In some implementations, the RB set is configured in the parameter ServingCellConfig for DL / UL channel access by defining the length and location of the guard band (also allowing a zero size guard band).

[0055] For SL-U positioning, a UE can transmit a Physical Shared Control Channel (PSCCH) and its corresponding SL-PRS in a shared spectrum. An initiating UE refers to a UE that initiates a channel access procedure and occupies a COT. The initiating UE is expected to transmit SL positioning related data in this COT. From the perspective of the initiating UE, the initiating UE performs a channel access procedure based on sensing / LBT, which evaluates the availability of the channel for SL positioning related transmissions. The COT occupied by the initiating UE can be shared by other UEs for SL positioning transmission purposes.

[0056] For SL positioning in a shared spectrum, dynamic channel access and semi-static channel access can be supported. From the perspective of the initiating UE, a dynamic channel access procedure is performed by the UE, where the duration spanned by the sensing slots that are sensed as idle prior to SL transmission is random or fixed based on dynamic SL positioning transmission needs. For semi-persistent channel access, the opportunity of the COT is periodic.

[0057] For SL positioning / ranging in an unlicensed band, without an LBT procedure, a UE cannot directly transmit SL-PRS resources based on network’s configuration / scheduling or UE’s autonomous resource selection (sensing, IUC, random resource selection). Figure 3 A diagram of candidate resource selection for transmitting SL-PRS is shown in accordance with various implementations. In Scheme 2, a UE first selects a candidate resource within a selection window 320 based on the sensing results performed within a sensing window 310. The UE can only transmit the selected SL-PRS resource 330 within the COT. In other words, the selected or configured SL-PRS resource cannot be transmitted in the case that the LBT procedure 340 is not successful. The UE initiates the COT or shares the COT with other UEs or BSs.

[0058] The basic unit for sensing is a sensing slot with a duration T sl = 9 ps. If the UE senses the channel during the sensing slot duration and determines that the detected power is less than the energy detection threshold X for at least 4 ps of the sensing slot duration Thresh , the sensing slot duration T sl is considered to be idle. Otherwise, the sensing slot duration T sl is considered to be busy. The example disclosed embodiments use the LBT duration or CCA time to represent the duration spanned by a sensing slot that is sensed to be idle prior to a SL transmission.

[0059] COT refers to the total time during which a UE and any UE / BS sharing the channel performs transmissions on the channel after the UE performs a corresponding channel access procedure. To determine the COT, if a transmission gap is less than or equal to 2525 ps, the gap duration is counted in the COT.

[0060] A SL transmission burst for SL positioning is defined as a set of SL transmissions (e.g., SL-PRS transmissions) from a UE for SL positioning without any gap larger than 16 ps. Transmissions from a UE separated by a gap larger than 16 ps are considered to be separate SL transmission bursts. A UE can transmit a SL transmission after a gap of up to 16 ps within a SL transmission burst without sensing the availability of the corresponding channel.

[0061] Figure 4 is a flowchart of an example method of transmitting SL positioning related transmissions, shown in accordance with various embodiments. The method 400 can be performed using the system 100.

[0062] 410, a first UE (e.g., UE 104a) performs a channel access procedure for at least one channel. In some examples, the first UE performs the channel access procedure (e.g., 420) prior to its transmission. A second UE (e.g., UE 104b) can or can not perform a channel access procedure.

[0063] The first UE can transmit, after the channel access procedure, a SL positioning related transmission intended to be transmitted to the second UE or a plurality of UEs (including the second UE) based on a cast type. For example, 420, the first UE communicates (e.g., sends or transmits to) the second UE a SL positioning related transmission using the at least one channel. The SL positioning related transmission includes at least one of a SL-PRS or a PSCCH corresponding to a SL-PRS. 430, the second UE communicates (e.g., receives from) the first UE the SL positioning related transmission using the at least one channel.

[0064] In some implementations, for SL positioning in a shared or unlicensed spectrum, a UE can perform a Type 1 channel access procedure in which the duration (spanned by the sensing slots that are sensed as idle before a SL transmission) is random. The UE can transmit a SL positioning related transmission after first sensing the channel to be idle during a sensing slot duration of a delay duration T d The counter N is adjusted by sensing the channel for an additional sensing slot duration. For example, the UE can 1) set N = N init , where N init is a random number uniformly distributed between 0 and CW p , and go to step 4; 2) if N > 0 and the UE chooses to decrement the counter, set N = N - 1; 3) sense the channel for an additional sensing slot duration, and if the additional sensing slot duration is idle, go to step 4; otherwise, go to step 5; 4) if N = 0, stop; otherwise, go to step 2; 5) sense the channel until a busy sensing slot is detected within an additional delay duration T d , or all sensing slot durations of the additional delay duration T d are detected to be idle; 6) if the channel is sensed to be idle during all sensing slot durations of the additional delay duration T d , go to step 4; otherwise, go to step 5.

[0065] In some implementations, in response to determining that the UE does not transmit after step 4 in the above procedure, if the channel is sensed to be idle for at least a sensing slot duration T sl when the UE is ready to transmit, and if the channel is sensed to be idle during all sensing slot durations of a delay duration T d immediately preceding that transmission, the UE can transmit on the channel. If the channel is not sensed to be idle for a sensing slot duration T sl when the UE first senses the channel after being ready to transmit, or if the channel is sensed not to be idle during any sensing slot duration of a delay duration T d immediately preceding that intended transmission, the UE goes to step 1 after sensing the channel to be idle during a sensing slot duration of the delay duration T d .

[0066] In some implementations, the UE does not transmit on a channel more than a maximum COT (T mcot,pCAPCtransmission on the channel of the COT of the first wireless communication device. The LBT duration and the maximum COT are associated with a CAPC according to a CAPC table for SL-U positioning. In some implementations, the CAPC table for SL-U positioning reuses the CAPC table for DL. In some implementations, the CAPC table for SL-U positioning reuses the CAPC table for UL. In some implementations, the CAPC table for SL-U positioning reuses the CAPC table for SL communication.

[0067] In some implementations, the CAPC table can be updated based on the CAPC table for DL, the CAPC table for UL, or the CAPC table for SL communication based on the SL-PRS configuration. In some implementations, one or more additional rows for SL positioning can be introduced in the CAPC table. For example, at least one additional candidate maximum COT can be introduced in addition to the candidate maximum COT range from 2ms to 10ms in legacy NR-U in FR2. To increase the probability of successful channel access, a lower maximum COT (e.g., T mcot,pCAPC = 1ms) can be introduced so that the UE can use a smaller LBT duration to access one or more channels. In some examples, the maximum COT is less than 2ms in SL-U positioning. In some examples, the maximum COT can be in the range of Xms - 2ms, where X is the slot length or determined based on the slot length. For example, X is 1ms at 15kHz and 0.5ms at 30kHz. In some implementations, the configuration of the CW of the SL positioning CAPC table can change based on the CAPC table for DL, the CAPC table for UL, or the CAPC table for SL communication.

[0068] In some implementations, the CAPC for SL positioning can be determined by the UE. The way of determining the CAPC applies to the dedicated resource pool or the shared resource pool for SL positioning.

[0069] In some implementations, the CAPC for SL-U positioning is associated with the SL-PRS configuration / feature. In some implementations, the channel access procedure includes a Type 1 channel access for determining the first UE’s SL positioning in an unlicensed band. The CAPC used in the Type 1 channel access for the first wireless communication device’s SL positioning corresponds to the LBT duration and the maximum COT. The CAPC corresponds to the configuration or feature of the SL-PRS.

[0070] In some implementations, the CAPC value or CAPC index is explicitly indicated, configured, or pre-configured. Thus, the CAPC value or CAPC index can be explicitly indicated, configured, or pre-configured as one of the configurations / features of the SL-PRS. In some implementations, the method 400 further includes receiving, by the first UE, an indication, configuration, or pre-configuration of the CAPC value or CAPC index corresponding to the CAPC as a configuration or feature of the SL-PRS.

[0071] In some implementations, the CAPC value can be configured or pre-configured per resource pool, per SL-PRS resource set, or per SL-PRS resource. For example, the BS can transmit / configure the CAPC information to the UE. In Radio Resource Control (RRC) signaling, the CAPC value can be configured or pre-configured per resource pool, per SL-PRS resource set, or per SL-PRS resource. In some examples, in a scheme 1 resource allocation, the BS can include the CAPC information in the downlink control information (DCI) or via a configured grant SL-PRS transmission or via a medium access control (MAC) control element (CE). In some implementations, at least one CAPC value is configured or pre-configured for each resource pool, or for each SL-PRS resource set, or for each SL-PRS resource.

[0072] In some examples where the CAPC value is configured per SL-PRS resource pool, the UE transmitting the SL-PRS in that slot would follow the type 1 channel access rule according to the unique CAPC. In some examples where the CAPC value is configured per SL-PRS resource set, different SL-PRS resource sets can have the same or different CAPC values. In some examples where the CAPC value is configured per SL-PRS resource, different SL-PRS resources can have the same or different CAPC values.

[0073] In some implementations, the UE 104a can receive the CAPC information from another UE. The Sidelink Positioning Protocol (SLPP) or PC5-RRC or SL MAC CE or Sidelink Control Information (SCI) can be used as a container for the CAPC information. The CAPC value can be configured or pre-configured per resource pool, per SL-PRS resource set, or per SL-PRS resource.

[0074] In some implementations, the LMF can transmit or configure or recommend the CAPC information to the UE 104a via Long Term Evolution Positioning Protocol (LPP) signaling. The CAPC value can be configured or preconfigured per resource pool, per SL-PRS resource set, or per SL-PRS resource. In some examples, the UE receives its CAPC value from the LMF using a procedure that includes the following steps: (1) the BS 102 first sends the CAPC and associated SL-PRS configuration to the LMF via NRPPa; (2) the LMF collects information from multiple BSs; (3) based on the service type and requirement, the LMF can request the BS to adjust the CAPC value of certain SL-PRS resources via NRPPa; (4) the BS 102 adjusts the CAPC value and sends the updated configuration to the LMF via NRPPa; (5) the LMF distributes the collected information to the UE via LPP, or the LMF adjusts the CAPC value of certain SL-PRS resources and distributes the collected information to the UE 104a. The higher layer of the UE 104a determines the CAPC value or CAPC index.

[0075] In some implementations, the first UE (e.g., the UE 104a) receives the CAPC from the BS 102 via at least one of RRC signaling, DCI, or MAC CE. In some implementations, the first UE receives the CAPC from the second UE (e.g., the UE 104b) or the third UE via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI. The third UE can be any UE different from the first and second UEs, and can be referred to as a server UE. In resource allocation scheme 2, the server UE can be used for positioning method determination, anchor UE selection, assistance distribution, and / or position calculation. The server UE can be used to transmit the CAPC configuration to the Tx UE. In some examples, the anchor UE or the target UE or any UE can be the server UE. In some implementations, the first UE receives the CAPC from the LMF via LPP.

[0076] In some implementations, the CAPC value or CAPC index is not explicitly represented as part of the SL-PRS configuration / feature. In other words, each CAPC is associated with one or more SL-PRS configurations / features. Based on the SL-PRS configuration / feature, the corresponding CAPC is known, thus saving signaling overhead. In some implementations, the method 400 further includes determining, by the first UE, the CAPC value or CAPC index using a mapping between the CAPC value or CAPC index and the configuration or feature of the SL-PRS.

[0077] In some implementations, the configuration or characteristics of the SL-PRS includes SL-PRS priority associated with the CAPC information. For example, the CW size (e.g., minimum, maximum, allowed) and the maximum COT duration of the SL-PRS CAPC table are related to or mapped to the SL-PRS priority. In one example with 8 SL-PRS priorities: {0, 1, 2, 3, 4, 5, 6, 7} and 4 CAPC values for SL positioning, there is a mapping relationship between the SL-PRS priority and the 4 CAPC values. For example, SL-PRS priority {0, 1} is related to CAPC {1}, SL-PRS priority {2, 3} is related to CAPC {2}, SL-PRS priority {4, 5} is related to CAPC {3}, and SL-PRS priority {6, 7} is related to CAPC {4}.

[0078] The implicit indication of the CAPC value saves the signaling overhead, assuming all devices in SL-U can use the same association relationship between the CAPC and the SL-PRS priority.

[0079] In some examples, the time-domain resource duration of the SL-PRS is associated with the COT value in the CAPC table. Based on the time-domain configuration of the SL-PRS (e.g., periodicity, repetition factor, time gap, number of symbols per slot, number of consecutive slots / symbols intended to be transmitted by the UE), one or more COT candidate values are known to be feasible. In an example where the consecutive SL-PRS transmission by the UE is 3ms, the required COT value is at least 3ms. The maximum COT of the SL-PRS CAPC table is related to or mapped to the duration of the SL-PRS transmission. Therefore, in some implementations, the configuration or characteristics of the SL-PRS includes the time-domain resource duration corresponding to the COT value in the CAPC table. The configuration of the time-domain resource duration includes at least one of periodicity, number of symbols per slot, repetition factor, time gap, number of consecutive slots / symbols intended to be transmitted by the first UE.

[0080] In some implementations, the CAPC for SL positioning and the SL-PRS configuration / characteristics are independent.

[0081] In some implementations, the CAPC information (e.g., CAPC value or CAPC index) for SL positioning is explicitly indicated / configured or pre-configured, depending on the higher layer configuration.

[0082] In some examples, the BS 102 can transmit or configure the CAPC information to the UE 104a. For example, the CAPC value can be configured or preconfigured for each resource pool. In some examples, in scheme 1 resource allocation, the BS 102 can include the CAPC information in the DCI or send to the UE 104a via configured grant SL-PRS transmission. In examples where the CAPC value is configured for each SL-PRS resource pool, the UE 104a transmits the SL-PRS in that time slot using Type 1 channel access rules according to the unique CAPC. In some examples, the UE 104a can receive the CAPC information from another UE. SLPP or PC5-RRC or SL MAC CE or SCI can be used as the container for the CAPC information. In some implementations, the method 400 further includes receiving, by the first UE, a CAPC for SL positioning of the first wireless communication device. In some examples, the first UE receives the CAPC from the BS 102 via at least one of RRC signaling, DCI, or MAC CE. In some examples, the first UE receives the CAPC from a UE or a third UE via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI. In some examples, the first UE receives the CAPC from the LMF via LPP.

[0083] In some examples, the LMF can transmit or configure the CAPC information to the UE via LPP signaling. The UE receives its CAPC value from the LMF using a procedure including the following steps: (1) the BS 102 first sends the CAPC and associated SL-PRS configuration to the LMF via NRPPa; (2) the LMF collects information from multiple BSs; (3) the LMF can request the BS to adjust the CAPC value via NRPPa according to the traffic type and demand; (4) the BS 102 adjusts the CAPC value and sends the updated configuration to the LMF via NRPPa; (5) the LMF distributes the collected information to the UE 104a via LPP, or the LMF adjusts the CAPC value for certain SL-PRS resources and distributes the collected information to the UE 104a.

[0084] In some implementations, the first UE receives the CAPC from the LMF. In some examples, the BS sends the CAPC and SL-PRS configuration corresponding to the CAPC to the LMF via first NRPPa signaling. The LMF receives information from multiple BSs and requests the multiple BSs to adjust the CAPC value via second NRPPa signaling. The multiple BSs adjust the CAPC value and send the adjusted configuration corresponding to the adjusted CAPC value to the LMF via third NRPPa signaling. The LMF distributes the adjusted configuration to the UE via LPP signaling.

[0085] In some implementations, the UE determines the CAPC information for SL positioning by itself, where there is no configuration / indication from the network, e.g., UE 104a does not receive the DCI.

[0086] In some examples, the method 400 further includes determining, by the first UE, the CAPC value for the SL positioning related transmission using a CAPC value included in at least one of a MAC CE, a common control channel (CCCH) service data unit (SDU), a dedicated control channel (DCCH) SDU, a MAC SDU, or a SL shared channel (SL-SCH) subheader. In examples where CAPC is not configured / indicated, the UE 104a selects the CAPC based on not only the priority CAPC of these MAC CEs, CCCH SDUs, DCCH SDUs, MAC SDUs, but also the priority CAPC of the SL-SCH subheader (the SL-SCH subheader includes L2 source / destination ID). In some examples, the highest priority CAPC is used in response to determining that only a MAC subheader and a SL-SCH subheader are included in the TB. For example, in a shared resource pool, the SL-PRS, the related PSCCH, and the PSSCH scheduled by the PSCCH are included in the same slot. The PSSCH can be used for the second stage SCI and the SL-SCH. The UE 104a can have no data available for transmission, the MAC PDU (SL-SCH) includes one SL-SCH subheader and one or more MAC subPDUs. Each MAC subPDU can include only a MAC subheader or a MAC subheader and padding.

[0087] In examples where only a MAC subheader and a SL-SCH subheader are included in the TB, the lowest priority CAPC is used. In examples where only a MAC subheader and a SL-SCH subheader are included in the TB, the highest priority CAPC is used. In examples where only a MAC subheader and a SL-SCH subheader are included in the TB, the lowest priority CAPC is used. In examples where only a SL-SCH subheader and MAC CEs are included in the TB, the highest priority CAPC of these MAC CEs is used. In examples where only a SL-SCH subheader and MAC CEs are included in the TB, the highest priority CAPC of these MAC CEs and the SL-SCH subheader is used. In examples where only a SL-SCH subheader and MAC SDUs are included in the TB, the lowest priority CAPC is used.

[0088] Some implementations relate to determining an appropriate CAPC value when multiple SL-PRS resources intended for transmission are associated with different priority values. Some implementations relate to determining an appropriate CAPC value when a UE intends to transmit SL-PRS and SL-data associated with different priority values. Some implementations relate to performing LBT in a potential COT associated with different priority values for multiple consecutive SL transmissions. Some implementations relate to determining a final priority. Some implementations relate to determining a COT in an example where multiple services are requested.

[0089] The UE 104a can initiate channel occupancy using the SL-PRS CAPC value and transmit SL-PRS accordingly. In an example where the SL-PRS CAPC value corresponding to the SL-PRS transmission is greater than or equal to the CAPC value corresponding to the SL data transmission, the UE 104a can continue transmitting SL data directly from the start of the SL data transmission. The total transmission duration of the SL-PRS transmission and the SL data transmission does not exceed the maximum COT corresponding to the SL-PRS CAPC value. In an example where the SL-PRS CPAC value corresponding to the SL-PRS transmission is less than the CAPC value corresponding to the SL data transmission, the UE 104a can terminate the SL-PRS transmission by dropping the transmission and attempt to transmit SL data according to the corresponding CAPC. In some examples, the UE 104a can also continue the SL-PRS transmission and ignore the SL data transmission.

[0090] In some examples, the UE 104a can initiate channel occupancy using the SL data CAPC value and transmit SL data accordingly. In an example where the SL data CAPC value corresponding to the SL data transmission is greater than or equal to the CAPC value corresponding to the SL-PRS transmission, the UE 104a can transmit SL-PRS directly from the start of the SL-PRS transmission. The total transmission duration of the SL-PRS transmission and the SL data transmission does not exceed the maximum COT corresponding to the SL data CAPC value. In an example where the SL data CPAC value corresponding to the SL data transmission is less than the CAPC value corresponding to the SL-PRS transmission, the UE 104a can terminate the SL data transmission by dropping the transmission and attempt to transmit SL-PRS according to the corresponding CAPC.

[0091] In some implementations, the UE 104a can determine a unified CAPC value to initiate channel occupancy for more than one SL transmission (e.g., SL-PRS transmission, SL data transmission). In some implementations, the method 400 further includes initiating, by the first UE (e.g., UE 104a), channel occupancy for two or more SL transmissions by determining a unified CAPC value. The SL transmissions include at least one of SL-PRS or SL data transmissions.

[0092] In some examples, the unified CAPC can be the highest priority CAPC for those SL transmissions, or the unified CAPC can be the lowest priority CAPC for those SL transmissions. In some examples, the UE can determine a unified CAPC value to initiate channel occupancy for SL-PRS transmission and SL data transmission. The unified CAPC value is related to or mapped to the SL-PRS transmission duration. The maximum COT corresponding to the unified CAPC value is greater than or equal to the sum of the transmission durations of the SL-PRS transmission and the SL data transmission. Channel occupancy is initiated at the beginning of the SL-PRS transmission using the unified CAPC value, and the SL-PRS transmission can be transmitted. In some examples, the SL-PRS transmission does not end before the SL data transmission starts, and the SL-PRS CPAC value corresponding to the SL-PRS transmission is greater than or equal to the CAPC value corresponding to the SL data transmission, the UE 104a can directly transmit the SL data from the start of the SL data transmission. In some examples, the SL-PRS CPAC value corresponding to the SL-PRS transmission is less than the CAPC value corresponding to the SL data transmission, the UE 104a can terminate the SL-PRS transmission by discarding the transmission, and attempt to transmit the SL data according to the corresponding CAPC. In some examples, the UE 104a can also continue the SL-PRS transmission and ignore the SL data transmission.

[0093] In some implementations, the CW adjustment mechanism in NR-U and SL-U can both be associated with HARQ-ACK feedback. When the likelihood of ACK feedback is above a threshold, the UE 104a can assume that the current channel condition is reliable, and thus a relatively short LBT duration or a short CW is sufficient for the CC. Otherwise, a longer LBT duration or a longer CW is needed. In a dedicated resource pool for SL positioning, acknowledgement (ACK) / negative acknowledgement (NACK) feedback or low-layer feedback based retransmission for SL-PRS is not supported (e.g., in Release 18). The implementations described in this example are related to introducing CW adjustment for SL positioning.

[0094] In some examples, the mentioned CAPC value can be an indicated / configured CAPC or a virtual CAPC. If a CAPC is explicitly indicated / configured, the indicated / configured CAPC value is. Otherwise, if no CAPC value is available, the device can assume a virtual CAPC based on SL-PRS configuration / features. Some implementations involve determining a CW for a SL positioning CAPC table. In some implementations, the method 400 further includes performing, by the first UE, a CCA for an LBT duration according to a CW size, and accessing, by the first UE, one or more SL channels for SL positioning with or without adjusting the CW size. In some examples, for Type 1 channel access, the actual LBT is random based on the CW size (related to CAPC) and actual channel assessment. For example, if the channel is sensed as busy, the UE 104a needs to continue performing LBT. Thus, it is difficult for the UE to determine the actual LBT duration.

[0095] In some implementations, for SL-U positioning, CW adjustment is disabled or cancelled. Figure 5 is a CAPC table according to various implementations. One example is shown in table 500, where each CAPC value corresponds to a fixed CW size CW p . There is no need to have 3 columns “CW min,p ”, “CW max,p ”, and “Allowed CW p size”, but only one column “CW p ” is enough.

[0096] In some examples, the number of CAPC values is equal to all configurable CW p for SL positioning. For example, if the candidates of CW p are {3, 7, 15, 31, 63, 127, 255, 511, 1023}, each CW p candidate can be associated with one CAPC value, where the higher the CAPC value, the higher the CW size. Different CAPC values can have the same or different CW sizes. In some examples, if each CAPC value still corresponds to two or more allowed CW p sizes, for each transmission of SL positioning, the UE 104a randomly selects one candidate CW p size without any CW adjustment mechanism. In some examples, if each CAPC value is associated with two or more allowed CW p candidates, the UE 104a can use CW p for channel access indicated / configured by another UE (via SLPP, PC5-RRC, SL MAC CE, SCI), LMF (via LPP), or BS 102 (via RRC, DCI, or MAC CE).

[0097] In some embodiments, the first UE accesses the one or more SL channels without adjusting the CW size. Each CAPC value is associated with a fixed CW size. Each CAPC value is associated with two or more CW sizes. The first UE randomly selects a candidate CW size from the two or more CW sizes for transmitting the corresponding SL-PRS. Each CAPC value is associated with two or more CW sizes, and the first UE uses the CW size for a channel access procedure indicated or configured by at least one of the BS 102, the second UE 104b, the third UE, or the LMF.

[0098] In some embodiments, CW adjustment is supported in SL-U positioning, and the CW size is associated with a channel access result. In other words, in a reliable channel condition, the CW size CW p may be set to a relatively small value. Otherwise, a longer time is needed to evaluate the availability of the channel. The method according to claim 400, further comprising adjusting, by the first UE, the CW size using the channel access result.

[0099] In some embodiments, the channel access can be associated with SL-PRS reference signal received power (RSRP) feedback or PSCCH DMRS RSRP of a Rx UE (e.g., UE 104b). The PSCCH is associated with or corresponds to the SL-PRS transmission.

[0100] Figure 6is a signaling diagram of an exemplary method of determining SL path loss based on power control, shown in accordance with various embodiments. In method 600, the Tx UE can be UE 104a and the Rx UE can be UE 104b. At 610, the Tx UE transmits SL-PRS / PSCCH DMRS to the Rx UE. At 620, the Rx UE performs RSRP measurement. At 630, the Rx UE transmits SL-PRS / PSCCH DMRS RSRP feedback to the Tx UE. At 640, the Tx UE determines SL path loss based on the SL-PRS / PSCCH DMRS RSRP feedback. At 650, the Tx UE transmits SL-PRS transmission based on power control, which is determined based on the SL path loss 640. Power control based on SL path loss requires the Rx UE to transmit SL-PRS / PSCCH DMRS RSRP feedback to the Tx UE via PC5-RRC. The Rx UE can transmit SL positioning related RSRP feedback (e.g., SL-PRS / PSCCH DMRS RSRP) to the Tx UE via SLPP, PC5-RRC, SCI, or SL MAC CE. The Tx UE can adjust or keep CW p .

[0101] The RSRP threshold can be configured or preconfigured to the UE by another UE, BS 102, or LMF via a respective one of LPP, SLPP, RRC, MAC CE, DCI, SL MAC CE. The RSRP threshold can be configured per UE or per BWP or per SL positioning resource pool or per SL-PRS resource or per SL-PRS resource set. If the received SL-PRS RSRP is higher than the RSRP threshold, the Tx UE can assume the channel is in good condition, and the Tx UE can keep CW p . Otherwise, the Tx UE increases CW p of each priority class to the next higher allowed value.

[0102] Figure 7is a signaling diagram of an exemplary method of adjusting CW based on measurement result feedback, shown in accordance with various embodiments. In method 700, the transmitting UE can be UE 104a and the receiving UE can be UE 104b. At 710, the Tx UE can transmit SL-PRS to the Rx UE. At 720, the Rx UE measures the SL-PRS. At 730, the Rx UE transmits SL-PRS RSRP feedback to the Tx UE. At 740, the Tx UE adjusts the CW based on the SL-PRS RSRP feedback. At 750, the Tx UE transmits SL-PRS transmission to the Rx UE after LBT. In method 700, the Tx UE successfully transmits SL-PRS in one or more channels in the most recent Type 1 channel access. After the Rx UE receives the SL-PRS, the Rx UE sends the SL-PRS RSRP back to the Tx UE. Before the next channel access by the Tx UE, the Tx UE compares the received RSRP with the RSRP threshold.

[0103] In some embodiments, the method 400 further includes receiving, by the first UE from the second UE, the measurement result of the SL-PRS or the measurement result of the PSCCH of the second UE via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI. The method 400 further includes adjusting or keeping the CW size, by the first UE, by comparing the measurement result of the SL-PRS or the measurement result of the PSCCH of the second UE with a measurement threshold.

[0104] In some embodiments, the Rx UE does not send SL-PRS RSRP feedback to the Tx UE. Instead, the Rx UE can indicate to the Tx UE whether and how to adjust the CW p . The indication of the CW adjustment can be conveyed through SCI or SLPP or PC5-RRC or SL MAC CE. For example, if SCI is used, a “CW adjustment indicator” can be designed as 2 bits, representing “keep”, “next higher level”, “next lower level”, and “minimum”, respectively. In some examples, “keep” instructs to reuse the last update of the CW, “next higher level” instructs to increase the CW for each priority to the next higher allowed value compared to the last update of the CW, “next lower level” instructs to increase the CW for each priority to the next lower allowed value compared to the last update of the CW, and “minimum” instructs to reset the CW to the minimum value allowed for each priority min,p . In some embodiments, the method 400 further includes receiving, by the first UE from the second UE, an indication indicating whether to adjust the CW size and adjustment information for adjusting the CW size via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI.

[0105] In some implementations, CW adjustment is supported in SL-U positioning, and each CAPC value or SL-PRS configuration / feature (e.g., SL-PRS priority) is associated with one or more CW p In this case, whether and how to adjust the CW size can be determined by another UE (via SLPP, PC5-RRC, SCI SL MAC CE) or LMF (via LPP), or by implementation of the UE or gNB (via RRC, DCI or MAC CE). In some implementations, each CAPC value or configuration or feature of the SL-PRS is mapped to two or more CW sizes. In some examples, the method 400 further includes receiving, by the first UE from the second UE via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI, an indication indicating whether to adjust the CW size and adjustment information for adjusting the CW size. In some examples, the method 400 further includes determining, by the first UE, whether to adjust the CW size and adjustment information for adjusting the CW size. In some examples, the method 400 further includes receiving, by the first UE from the BS 102 via at least one of RRC signaling, DCI, or MAC CE, an indication indicating whether to adjust the CW size and adjustment information for adjusting the CW size. In some examples, the method further includes receiving, by the first UE from the LMF via LPP, an indication indicating whether to adjust the CW size and adjustment information for adjusting the CW size.

[0106] In some implementations, another UE (via SLPP), LMF (via LPP), implementation of the UE, or the BS 102 (via RRC, DCI or MAC CE) can indicate or determine which CW p candidate should be used, including whether the latest CW p should be reused, whether the CW p should be adjusted to the next higher level or the next lower level, whether the CW p should be set to the minimum or maximum value, or specifically which CW p should be used.

[0107] In some implementations, no feedback is available, and for each priority class, the CW p = CW min,p or the latest CW used for any SL-PRS transmission on the channel is reused using Type 1 channel access procedure associated with the CAPC p p . In some examples, if no feedback is available, and the CW p is used for X consecutive times, the CW pis updated by the first UE. For example, X can be a preconfigured value or configured by the BS 102 for a resource pool or for a SL BWP. For example, CW p is used X times in a row, CW p is updated to the next higher allowed value. For example, CW p is used X times in a row, CW p is updated to a priority class CW min,p is the minimum value allowed.

[0108] In some implementations, the CW adjustment can be achieved by CAPC value adjustment. In some examples, the first UE adjusts the CAPC value in response to determining that the number of LBT failures is greater than N or in response to detecting consistent SL-PRS LBT failures. In some examples, the first UE adjusts the CAPC value depending on whether it is an initial SL-PRS transmission or a retransmission. In some examples, the first UE adjusts the CAPC value based on channel conditions. In some examples, the first UE can receive a CAPC adjustment indication from another UE (via SLPP, PC5-RRC, SCI SL MAC CE), LMF (via LPP), or gNB (via RRC, DCI, or MAC CE), or the first UE can determine the CAPC adjustment by itself.

[0109] In some implementations, the method 400 further includes adjusting, by the first UE, the CW size by adjusting a CAPC value. In some examples, the method 400 further includes receiving, by the first UE from a second UE, an indication indicating whether to adjust the CAPC value and adjustment information for adjusting the CAPC value via at least one of SLPP signaling, PC5-RRC signaling, SL MAC CE, or SCI. In some examples, the method 400 further includes determining, by the first UE, whether to adjust the CAPC value and adjustment information for adjusting the CAPC value. In some examples, the method 400 further includes receiving, by the first UE from a BS 102, an indication indicating whether to adjust the CAPC value and adjustment information for adjusting the CAPC value via at least one of RRC signaling, DCI, or MAC CE. In some examples, the method 400 further includes receiving, by the first UE from a LMF, an indication indicating whether to adjust the CAPC value and adjustment information for adjusting the CAPC value via LPP.

[0110] In some implementations, the determining whether to adjust the CAPC value and adjustment information for adjusting the CAPC value is based on one of LBT failure time, initial transmission or retransmission for SL positioning, or channel conditions.

[0111] In some implementations, for a Type 2 channel access procedure for SL positioning, the duration spanned by the sensing slots (for LBT) that are sensed to be idle prior to SL-PRS transmission or prior to PSCCH transmission associated with one or more SL-PRS resources is deterministic. In some implementations, the channel access procedure in method 400 includes Type 2 channel access for determining, prior to SL positioning related transmissions, that the first UE is in SL positioning in an unlicensed band. Method 400 further includes sensing, by the first UE, a duration of time that at least one sensing slot of LBT is in an idle state prior to the SL positioning related transmissions. The LBT duration is deterministic.

[0112] In some examples, for Type 2A channel access, when the UE 104a uses a Type 2A UL channel access procedure for SL positioning transmissions, the UE 104a can transmit the transmission immediately after sensing the channel to be idle for at least a sensing interval T short_sl-p = 25 μβ. T short_sl-p includes a sensing slot immediately following T f = 16 μβ. T f includes a sensing slot at the beginning of T f . In response to determining that both sensing slots of T short_sl-p are sensed to be idle, the channel is considered to be idle for T short_sl-p .

[0113] In some examples, for Type 2B channel access, when the UE 104a uses a Type 2B UL channel access procedure for SL positioning transmissions, the UE 104a can transmit the transmission immediately after sensing the channel to be idle for a duration of T f = 16 μβ. T f includes a sensing slot occurring within the last 9 us of T f . In response to determining that the channel is sensed to be idle for at least 5 us in total, and at least 4 us of sensing occurs in the sensing slot, the channel is considered to be idle for the duration of T f .

[0114] In some examples, for Type 2C channel access, when the UE 104a uses a Type 2C UL channel access procedure for SL positioning transmissions, the UE 104a does not sense the channel prior to the transmission. The duration of the corresponding SL transmission is at most 584 us. In this case, the LBT gap prior to the SL transmission is 16 us.

[0115] Some implementations involve Type 2 channel access for SL positioning in non-COT shared scenarios. In non-COT shared scenarios, in response to determining that certain conditions are met, the UE can use Type 2 channel access to transmit SL positioning-related transmissions (e.g., SL-PRS transmissions). In some examples, one or more conditions are met in order to use the Type 2 channel access procedure (e.g., Type 2A, Type 2B, or Type 2C).

[0116] In some examples, the condition includes a PSCCH / SL-PRS transmission duration of up to 1 ms. In some examples, the condition includes a PSCCH / SL-PRS transmission duty cycle of up to 1 / 20. In some examples, the condition includes an SL-PRS transmission with a priority higher than a certain bar / threshold. In other words, the SL-PRS transmission priority value is lower than a threshold. This threshold can be configured by the BS102, LMF, or another UE, or it can be configured based on a pre-configuration, where the same threshold applies to all devices involved in SL positioning. In some examples, this condition is associated with SL-PRS configuration / characteristics. For example, the periodicity and number of symbols within a time slot are related to whether the UE can use the Type 2 channel access procedure. In some examples, the condition includes an SL-PRS transmission CAPC lower than a threshold. This threshold can be configured by the BS102, LMF, or another UE, or it can be configured based on a pre-configuration, where the same threshold applies to all devices involved in SL positioning. In some implementations, method 400 further includes determining, based on at least one of the following: duration of SL location-related transmission, duty cycle, SL-PRS priority, CAPC, number of symbols in a period or time slot, that a first UE (e.g., UE 104a) can access the network using a type 2 channel.

[0117] In some examples, Type 2 channel access for SL location-related transmissions can be used in COT shared scenarios. Figure 8 This is a schematic diagram illustrating an exemplary Type 2 channel access procedure for SL positioning transmission used in a COT sharing scenario, according to various implementation methods. Figure 8 As shown, a UE (e.g., UE 2, the responding UE, or UE 104a) intends to transmit an SL location-related transmission (e.g., an SL-PRS transmission) after an SL transmission performed by another UE (e.g., UE 1, the initiating UE) during shared channel occupancy. The UE (e.g., UE 2) can use a Type 2 channel access procedure. UE 1 can initiate COT 810 with a maximum COT duration 820, which includes UE 1's SL transmission 830, UE 2's SL transmission 850, and the LBT gap 840 between them.

[0118] In some examples, for the container and contained information for UE-to-UE COT sharing for SL positioning, the UE-to-UE COT sharing information for SL positioning is transmitted from the initiating UE to one or more responding UEs. UE 2, as a responding UE, can transmit its SL-PRS in the shared COT (at 850) in response to determining that certain conditions are satisfied, e.g., the SL-PRS resources that the responding UE is to transmit are within the shared COT (e.g., 810), etc. One or more types of information can be included as the UE-to-UE COT sharing information for SL positioning.

[0119] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes time domain information of the COT. This can include one or more COT durations, each of which can be associated with a starting offset. The COT duration can be the entire, whole, or total COT duration occupied by the initiating UE, or the COT duration can be the remaining COT duration (in other words, the initiating UE (e.g., UE 1) can exclude all of its own transmission resources for half-duplex reasons or to avoid resource collisions), or the indicated COT duration includes only a portion of the total COT. The COT sharing duration can include one slot, multiple slots, or one or more symbols, a portion of a slot, etc.

[0120] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes frequency domain information of the COT. This can include the full set of RBs, the set of available RBs, or one or more sets of RBs that the initiating UE wants to share with the responding UEs.

[0121] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes source ID and / or destination ID. The source and / or destination ID pair can be the same as or different from that used in the single-stage SCI of the dedicated resource pool or the second-stage SCI of the shared resource pool. In some examples, one or a list of source and / or destination ID pairs can be included.

[0122] In some examples, the UE-to-UE COT sharing information for SL positioning includes a group ID indicating that the COT can be shared among a group of UEs. The group ID can include multiple UE ID information of multiple UEs or only group information of a UE group. The group ID is received by the UE from a higher layer, which can be the UE’s own higher layer or another UE’s higher layer signaling (e.g., SLPP) or from the network (e.g., RRC, LPP). For example, in SL-TDOA positioning, an anchor UE can share its initiated COT to other anchor UEs. The anchor UEs involved in one S1-TDOA positioning are in one group.

[0123] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes a CAPC of the initiating UE. Based on the CAPC of the responding UE and the CAPC of the initiating UE, this can be a factor of whether the responding UE can use the COT or not. In examples where this field is not present, the SL-PRS transmission priority of the COT initiating UE is needed.

[0124] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes a SL-PRS transmission priority of the initiating UE.

[0125] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes an indicator of whether the COT is a common COT or not. The indicator can be one bit. For example, “0” means that the COT sharing is only allowed for those responding UEs that have SL-PRS transmission interaction with the initiating UE, while “1” means that all UEs receiving this COT information can share the COT resource.

[0126] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes one or a list of COT sharing information for SL positioning. The total COT can be multiple parts / combinations, where each COT combination is associated with one source and / or destination ID pair. One COT combination can include {a part of COT duration, one starting offset, one or multiple RB sets}, and one UE pair can represent a source and / or destination pair.

[0127] Figure 9 is a diagram of one COT shared by different responding UEs according to various embodiments. As shown in Figure 9 The COT initiating UE can share {UE pair 1, COT duration 1, starting offset 1, RB set 1} in resource 910 with responding UE 1, and {UE pair 2, COT duration 2, starting offset 2, RB set 2} in resource 920 with responding UE 2. The total COT duration 930 includes resources 910 and 920. One list of COT sharing information can be conveyed by a single container, or each COT sharing information is conveyed by a single container.

[0128] In some examples, the information included as the UE-to-UE COT sharing information for SL positioning includes one COT sharing information for SL positioning and additional source and / or destination ID pair information. In this case, the initiating UE intends to share the COT to multiple responding UEs, where each or multiple responding UEs can be associated with one source and / or destination ID pair based on whether the SL-PRS is unicast or groupcast or broadcast.

[0129] In some implementations, the method 400 further includes receiving, by the first UE from the second UE or the third UE, COT sharing information for SL positioning, the COT sharing information including at least one of time domain information of the COT, frequency domain information of the COT, one or more UE pair information, a CAPC of the first UE, a SL-PRS priority of the first wireless communication device, or a common COT indicator, or a group ID. In some examples, the first UE has a SL positioning related transmission to transmit. The second UE or the third UE has occupied one or more channels and transmitted the COT sharing information to the first UE. The first UE performs Type 2 channel access and transmits using the COT initiated by the second / third UE.

[0130] In some implementations, the SCI can be used as a container for UE-to-UE COT sharing for SL positioning. In a dedicated resource pool for SL positioning, unlike the traditional SL communication design, both the first stage SCI and the second stage SCI are needed for scheduling and decoding PSSCH. Only a single stage SCI is located in the dedicated resource pool. In some implementations, the reserved bits in this single stage SCI can not be sufficient to contain the UE-to-UE COT sharing information. In some examples, limited reserved bits can be left for the single stage SCI of the dedicated resource pool.

[0131] In some examples, one UE broadcasts the COT information, where, by default, the frequency domain of the COT sharing information is the same as the SL-PRS transmission bandwidth of the initiating UE. Only the COT duration is contained in such COT sharing container.

[0132] In some examples, the SCI only includes a 1-bit field for a transmission permission indicator, which indicates whether the reserved resource of the responding UE in the COT is available for transmission. In some examples, for SL round trip time (RTT) positioning methods, there is a round trip transmission between two UEs. Figure 10 is a signaling diagram of an exemplary method of COT sharing in SL-RTT positioning shown in accordance with various implementations. As Figure 10As shown, UE 1 first transmits SL-PRS resources to UE 2 at t0, which are received by UE 2 at t2. Then, UE 2 transmits SL-PRS resources back to UE 1 at t2, which are received by UE 1 at t3. UE 1 transmits SL-PRS resources to UE 2 at t4, t0, which are received by UE 2 at t1. In this case, UE 1 can first initiate COT 1010 to transmit at t0. The two UEs can know each other’s transmission occasions with the help from a server UE or LMF. In response to UE 1 determining that UE 2 intends to transmit at t2 and t2 is within its COT 1010, UE 1 only needs to inform UE 2 whether UE 2 can transmit at t2.

[0133] In some examples, the SL-PRS request field is included in SCI for triggering SL-PRS. UE 1 can request UE 2 to transmit S1-PRS. This field can be repurposed to indicate whether the initiating UE is ready to share COT or this field can be repurposed for transmission grant indicator. In some examples, the SL-PRS request field and the transmission grant indicator field can be combined. In some examples, SL-PRS transmission and COT are requested to be shared (given transmission grant). In some examples, SL-PRS transmission is not requested and COT cannot be shared by the responding UE.

[0134] In some implementations, COT sharing information is included in SCI. The SCI includes a field to indicate whether the first UE’s reserved SL-PRS resources are available for transmitting SL-PRS or not depending on whether the reserved SL-PRS resources are within the second UE’s initiated COT. A new field in SCI or the SL-PRS request field is used for the indication.

[0135] In some implementations, for a shared resource pool, SCI is supported for triggering SL-PRS transmission. This field can be repurposed to indicate whether the initiating UE is ready to share COT or this field can be repurposed for transmission grant indicator. In some examples, the SL-PRS request field and the transmission grant indicator field can be combined together. In some examples, SL-PRS transmission and COT are requested to be shared (given transmission grant). In some examples, SL-PRS transmission is not requested and COT cannot be shared by the responding UE.

[0136] In some examples where SCI is not used as the container for UE-to-UE COT sharing for SL positioning, one of SL MAC CE or SLPP can be used as the container. In a dedicated SL-PRS resource pool, there is no transmission of PSSCH, so SL MAC CE can not be used. In some implementations, COT sharing information is included in at least one of MAC CE or SLPP signaling.

[0137] In some implementations, with respect to the relationship (COT sharing condition) between UEs participating in COT sharing, in SL positioning, an initiating UE can share its COT to one or more UEs. COT sharing information can be transmitted using unicast, in which case the initiating UE intends to share its COT with a specific responding UE. In some examples, COT sharing information can be transmitted using groupcast. For example, in SL-Downlink-like Time Difference of Arrival (TDOA) positioning, multiple anchor UEs transmit SL-PRSs to a target UE respectively. Once one anchor UE successfully occupies a COT, the anchor UE can share the COT to the other anchor UEs involved. In some examples, all anchor UEs involved in one SL-TDOA positioning are in one group. The COT can be shared within the group. Further, COT sharing information can be transmitted using broadcast, in which case all UEs receiving the SCI containing the COT sharing information can perform Type 2 channel access for their SL-PRS transmissions.

[0138] In some implementations where COT sharing information is transmitted using broadcast, a responding UE can be a UE that satisfies one or more conditions. In some examples, a responding UE can be a receiving UE, which is a target of SL-PRS transmission by a COT initiating UE. In some examples, SL-PRS transmission by a responding UE within a set of RBs corresponding to a shared COT is intended for the COT initiating UE. In some examples, SL-PRS transmission by a responding UE within a set of RBs corresponding to a shared COT is not intended for the COT initiating UE. In some examples, SL-PRS transmission by a responding UE within a set of RBs corresponding to a shared COT is intended for the same UE as SL-PRS transmission by the initiating UE within the set of RBs. For example, the responding UE and the initiating UE have the same destination ID.

[0139] In some implementations, with respect to the relationship between CAPC / SL-PRS priority value between an initiating UE and a responding UE related to COT sharing, a first UE can perform PSCCH / SL-PRS transmission in response to one or more conditions. For example, a high priority transmission can share a COT initiated by a low priority transmission, but a low priority transmission can share a COT initiated by a high priority transmission. In some examples, SL positioning related transmission by a responding UE within a set of RBs corresponding to a shared COT can be transmitted in response to determining that a CAPC value of the SL transmission has a CAPC value equal to or less than a CAPC value indicated in the COT sharing information. In some examples, SL positioning related transmission by a responding UE within a set of RBs corresponding to a shared COT can be transmitted in response to determining that a SL-PRS transmission priority has a priority value equal to or less than a priority value of a transmission by an initiating UE.

[0140] In some examples, there is no need to limit the SL-PRS priority or CAPC value of the responding UE. In the sensing selection process, the sensed RSRP threshold already considers the SL-PRS transmission priority of both UEs. In response to determining that the CAPC is associated with the SL-PRS priority, there is no need to further introduce more restrictions on the CAPC values of the initiating UE and the responding UE.

[0141] In some implementations, as to whether UE-to-UE COT sharing is supported in SL-TDOA positioning, three cases can apply for SL-TDOA scenarios.

[0142] In the first case, an anchor UE can share its initiated COT to other anchor UEs in SL-TDOA positioning. In a similar DL-like SL-TDOA positioning, multiple anchor UEs transmit SL-PRS to a target UE respectively. Once one anchor UE successfully occupies a COT, the anchor UE can share the COT to other anchor UEs involved. Figure 11 is a schematic diagram of exemplary COT sharing within a group shown in accordance with various implementations. In some examples, all anchor UEs involved in one SL-TDOA positioning (e.g., anchor UE 1, UE 2, and UE 3) are in a COT sharing group 1100. COTs can be shared within one UE group. Specifically, the LMF, a server UE, or the BS 102 can inform each anchor UE in the group of the UE group information (e.g., UE ID or source / destination ID). Each of the anchor UE 1, UE 2, and UE 3 transmits a corresponding one of S1-PRS1, S1-PRS2, and S1-PRS3 to the target UE 1110.

[0143] In some implementations, the LMF can transmit the UE group information for COT sharing to a UE via LPP. In some implementations, the BS 102 can configure the UE group information via DCI, RRC, or MAC CE in order to share the COT with the UE. In some implementations, a UE (e.g., a server UE) can transmit the UE group information for COT sharing to a UE via SLPP, SL MAC CE, or SCI.

[0144] In some implementations, an initiating UE (e.g., an anchor UE) can share its COT to a UE (e.g., other anchor UEs) only when multiple UEs including the initiating UE transmit SL-PRS to the same UE (e.g., a target UE).

[0145] In the second case, for SL-TDOA positioning method, UE-to-UE COT sharing is not supported. In this case, whether UE-to-UE COT sharing can be used is associated with the SL positioning method. The use case of UE-to-UE COT sharing can be limited to SL-RTT positioning method.

[0146] In the third case, a target UE or another UE (e.g., a server UE) can share its initiated COT to one or more anchor UEs. In DL-like SL-TDOA positioning method, multiple anchor UEs transmit SL-PRS to a target UE. The target UE does not need to further transmit SL-PRS to anchor UEs. The target UE can initiate a COT, but only transmit SCI. The SCI can be considered as a standalone SCI.

[0147] In some examples, a server UE can share an initiated COT to one or more anchor UEs. In SL positioning, a server UE can be used to determine the positioning method, select anchor UEs. Distribute assistance data and / or compute the position. Therefore, the server UE can be aware of all SL-PRS transmission occasions of anchor UEs participating in DL-like SL-TDOA positioning. Based on the SL-PRS transmission occasions of all anchor UEs, the server UE can occupy one or more channels with the largest COT time and further share this COT with anchor UEs. The server UE can first request SL-PRS configurations of anchor UEs via SLPP.

[0148] In some embodiments, in a dedicated resource pool or a shared resource pool, one UE (e.g., UE 1) can use at least SCI to request SL-PRS transmission of another UE (e.g., UE 2). In SL-U positioning, even if UE 2 receives the request of UE 1, UE 2 can fail to assess the channel due to LBT failure. Some rules can be configured, preconfigured, or set.

[0149] In some embodiments, when UE 1 sends SL-PRS request to UE 2 N times and UE 1 cannot receive SL-PRS of UE 2, UE 1 can assume that UE 2 has difficulty in accessing the channel, therefore UE 1 can share its initiated COT with UE 2. In some embodiments, when UE 1 sends “SL-PRS request” to UE 2, but after time T (the unit of T can be ms, slot, symbol, etc.), UE 1 still cannot receive SL-PRS of UE 2, UE 1 can consider that UE 2 has difficulty in accessing the channel, therefore UE 1 can share its initiated COT with UE 2. In some embodiments, UE 1 sends SL-PRS request to UE 2 as well as COT sharing information.

[0150] Some embodiments are related to IUC depending on COT availability. For IUC scheme 1, a UE (e.g., UE A) can send a preferred or non-preferred set of resources to another UE (UE B) in response to a request by UE A or based on implementation by UE A. In addition, for a shared resource pool, existing IUC scheme 1 and IUC scheme 2 are supported. In some examples, for UE A, whether a SL-PRS resource is preferred depends on collision cases and half duplex cases. However, it is considered that whether a SL-PRS resource is preferred for SL-U IUC can depend on whether the SL-PRS resource is within a COT known to UE A. For example, UE A checks whether the SL-PRS resource is within a COT initiated by it.

[0151] In some embodiments, a CAPC value of a SL positioning transmission by a first UE is equal to or less than a CAPC value used by a second UE or a third UE to initiate a COT. In some embodiments, a SL-PRS transmission priority value of a first UE is equal to or less than a SL-PRS transmission priority value used by a second UE or a third UE to initiate a COT. In some embodiments, a SL-PRS transmission by a second UE or a third UE is to a first UE. In some embodiments, a SL-PRS transmission by a first UE in a shared COT is to a second UE. In some embodiments, a SL-PRS by a UE in a shared COT and a SL-PRS by a third UE are transmitted to a same second UE.

[0152] In some embodiments, in NRU channel access, a BS 102 can share its initiated COT to a UE for its UL transmission. Figure 12 is a schematic diagram of exemplary gNB-to-UE COT sharing in NRU shown in accordance with various embodiments. As shown, after an LBT gap 1240, a UE transmits an UL transmission 1250 in a shared COT 1210. A BS (e.g., gNB) initiates the COT 1210. The BS can transmit a DL transmission 1230 to the UE within the COT 1210. The COT has a maximum solidification 1220, which includes the DL transmission 1230, the LBT gap 1240, and the UL transmission 1250. Figure 12

[0153] Figure 13 is a schematic diagram of exemplary gNB-to-UE COT sharing in SL-U positioning shown in accordance with various embodiments. As shown, after an LBT gap 1240, a UE transmits an UL transmission 1250 in a shared COT 1210. A BS (e.g., gNB) initiates the COT 1210. The BS can transmit a DL transmission 1230 to the UE within the COT 1210. The COT has a maximum solidification 1220, which includes the DL transmission 1230, the LBT gap 1240, and the UL transmission 1250. Figure 13 ​As shown, after the LBT gap 1340 and the SL transmission 1360, the UE transmits an UL transmission 1350 in the shared COT 1310. The BS (e.g., gNB) initiates the COT 1310. The BS can transmit a DL transmission 1330 to the UE within the COT 1310. The COT has a maximum solidification 1320, which includes the DL transmission 1330, the LBT gap 1340, the SL transmission 1360, and the UL transmission 1350. In SL-U positioning, the BS can share its initiated COT 1310 to the UE for its SL transmission 1360. In some examples, the SL transmission 1360 can be a SL-PRS transmission scheduled or configured by the BS 102 via dynamic grant or configured grant in resource allocation scheme 1.

[0154] In some implementations, the BS 102 initiates a COT and shares the COT with a first UE for SL positioning related transmissions. The SL positioning related transmissions are scheduled or configured by the BS. In some implementations, with respect to the container for gNB-to-UE COT sharing for SL positioning, in SL positioning resource allocation scheme 1, DCI or MAC CE or RRC can be used to convey gNB-to-UE COT information for SL positioning purposes. One or more types of information are carried (for scheduling purposes and COT sharing purposes). In some examples, the information includes a SL transmission indicator carried in the DCI, MAC CE, or RRC. The SL transmission indicator indicates whether the COT is available for SL-PRS transmission. If not available for SL-PRS transmission, the COT can only be shared by the UE to the BS 102 for UL transmission.

[0155] In some examples, the information includes frequency domain resources, e.g., available RB set or total RB set or partial RB set. In some examples, the information includes time domain resources, e.g., available COT duration or total COT duration or partial COT duration. In some examples, the information includes a feedback indicator indicating whether feedback is needed. The UE can need to transmit feedback information to the BS via PUCCH to indicate whether an SL-PRS resource is successfully transmitted.

[0156] In some examples, the information includes a channel access type, e.g., Type 1 channel access, Type 2A channel access, Type 2B channel access, Type 2C channel access, etc. In some examples, the information includes a CAPC. For example, if Type 1 channel access is indicated, the CAPC value is intended for the UE to perform Type 1 LBT for SL-PRS transmission. If Type 2 channel access is indicated, the CAPC is used by the BS to perform Type 1 LBT for DL transmission. In some examples, the information includes a CP extension length related indication. In some examples, there is no need to restrict the UE to have to transmit data / RS to the BS.

[0157] In some implementations, the BS shares the COT with the first UE using at least one of RRC signaling, DCI, or MAC CE. The information for sharing the COT includes at least one of an indicator indicating whether the COT is for SL positioning related transmissions, a frequency domain of the COT, a time domain of the COT, a PUCCH feedback related indication, a channel access type or CAPC, or a CP extension length related indication. In some implementations, the first wireless communication device shares its COT with a base station (BS) via uplink control information (UCI) after a successful channel access for DL transmissions.

[0158] In some implementations, the DCI can be a group common DCI (e.g., DCI format 2-0) for COT sharing, or a SL positioning scheduling DCI (e.g., DCI format 3-0), or a newly introduced DCI format for SL-U positioning. Figure 14 is a diagram illustrating an example of a gNB scheduling SL-PRS transmissions of different UEs within one COT 1410 according to various embodiments. As shown, a BS 102 (e.g., a gNB) can schedule SL-PRS transmissions 1430 and 1440 of different UEs within one COT 1410 without any collision caused by any wireless communication device. The BS 102 can initiate the COT 1410, where the BS 102 can transmit a downlink transmission 1420 to a UE. Thereafter, within the same COT 1410, the BS 102 schedules an SL-PRS transmission 1430 for UE 1 and an SL-PRS transmission 1440 for UE 2. The SL-PRS transmission 1430 is defined by a COT duration 1, a starting offset 1, and a RB set 1. The SL-PRS transmission 1440 is defined by a COT duration 2, a starting offset 2, and a RB set 2. Figure 14

[0159] Figure 15 is a diagram illustrating an example of UE-to-gNB COT sharing in SL-U positioning according to various embodiments. As shown, a UE transmits an SL / UL transmission 1530 in a UE-initiated COT 1510 before an LBT gap 1540, and receives a DL transmission 1550 after the LBT gap 1540. The UE initiates the COT 1510. That is, the UE can share its initiated COT via UCI to a BS 102 (e.g., a gNB) for SL positioning transmissions. The BS 102 can further use the UE-initiated COT for the DL transmission 1550. The COT 1510 has a maximum solidification 1520, which includes the SL / UL transmission 1530, the LBT gap 1540, and the DL transmission 1550. Figure 15

[0160] ​​In some embodiments, in the R16 NRU, a basic channel is associated with a RB set. For wideband transmission, the BS or UE needs to follow a multi-channel access procedure to access multiple channels or multiple RB sets. In SL positioning, for a dedicated resource pool, the SL-PRS bandwidth is the same as the bandwidth of the supporting resource pool. The SL-PRS resource pool and related SL-PRS resources are contained in a single SL BWP and carrier. Figure 16 is a diagram illustrating the relationship between the bandwidth of a dedicated resource pool and the RB set according to various embodiments. As shown in Figure 16 , one dedicated resource pool 1600 can be configured to include at least an integer number of RB sets, e.g., RB set 0, RB set 1, RB set 2, etc. In the example where the transmission bandwidth of SL-PRS is the same as the bandwidth of the dedicated resource pool, the UE needs to access multiple channels (multiple RB sets, Figure 16 , 3 RB sets) for transmitting SL-PRS in multiple RB sets. The RB sets are separated by guard bands (GB).

[0161] In some embodiments, the location and number of RB sets and GB are configured in IEServingCellConfig. The location and number of RB sets and GB for SL positioning transmission can be configured to be different from the location and number of UL or DL transmission by the BS via RRC signaling. For example, an IE “intraCellGuardBandsSL-List” can be added in ServingCellConfig, as shown in Figure 17 .

[0162] Regarding multi-channel access for SL positioning, one or more procedures / types should be applied before the UE transmits SL-PRS. In some examples, for multi-channel access type A for SL positioning, the UE needs to perform type 1 channel access on each channel of the channel set. In some examples, for multi-channel access type B for SL positioning, the UE only needs to perform type 1 channel access on one channel of the channel set, and other channels in the channel set only need to perform type 2 channel access (e.g., 25 μs CCA).

[0163] In some examples, the UE can consider the transmission frequency range of the SL-PRS and / or the transmission frequency range of the associated PSCCH to further determine whether multi-channel access can be applied and the number of channels to access. The multi-channel access procedure (e.g., LBT procedure for each channel) starts at the same time, but the actual SL positioning related transmission time can be different. The transmission start time / point for each channel involved in the multi-channel access can be different. For example, the PSCCH starts at symbol #1 of the slot and only occupies channel / RB set #1, but the SL-PRS transmission starts at symbol #4 of the slot and occupies channel / RB sets #1, 2, and 3. The UE performs multi-channel access for channel / RB sets #1, 2, and 3, but the transmission start point / time in channel / RB set #1 and the transmission in channel / RB sets #2 and 3 are different.

[0164] In some examples, the UE can transmit or not transmit the SL-PRS only when the UE has successfully accessed all of the channels in the group of channels. In some examples, the UE can transmit the SL-PRS only when the UE has successfully accessed all of the channels in the group of channels. In some examples, the UE can transmit the SL-PRS on those accessed channels in the group of channels, the UE can successfully access only some of the channels in the group of channels.

[0165] In some implementations, for the SL positioning multi-channel access procedure, the UE can transmit the SL-PRS on those channels only when the UE has successfully accessed all of the channels in the group of channels. In some examples, transmitting the SL-PRS on those channels is independent of whether the UE is configured with an in-cell guard band. If the UE is configured without / with an in-cell guard band on the SL bandwidth part and the UE fails to access any of the channels of the UL bandwidth part, the UE can not transmit on the channels within the carrier bandwidth.

[0166] In some examples, transmitting the SL-PRS on those channels depends on whether the UE is configured with an in-cell guard band. If the UE is configured without an in-cell guard band on the SL bandwidth part and the UE fails to access any of the channels of the UL bandwidth part, the UE can not transmit on the channels within the carrier bandwidth. If the UE is configured without an in-cell guard band on the SL bandwidth part and the UE fails to access any of the channels of the UL bandwidth part, the UE can transmit on the channels within the carrier bandwidth.

[0167] In some implementations, for SL positioning multi-channel access procedure, if a UE successfully accesses only some of the set of channels, the UE can transmit SL-PRS on those accessed channels. In some examples, the UE can transmit SL-PRS on the partial channels in the channel set only if the UE successfully accesses one or more contiguous RB sets. For example, there are 3 RB sets {0, 1, 2} in total, if successfully accessed, the UE can transmit SL-PRS on RB sets {0, 1} or {1, 2} or {1, 2, 3}. In some examples, the UE can transmit SL-PRS on the partial channels in the channel set only if the UE successfully accesses more than (or equal to) N RB sets. If less than N RB sets, the UE does not transmit SL-PRS. Regarding the configured value N, the UE or LMF can request / configure the minimum number N using SLPP or LPP, respectively. The BS can convey the requested N value to the UE via RRC or DCI or MAC CE. The number of N can be associated with the server accuracy request.

[0168] In some implementations, if non-contiguous RB sets are successfully accessed, the UE can transmit SL-PRS on one of these channels.

[0169] The priority of each channel can be configured or pre-configured, where different RB sets can have different priorities. The UE or LMF can request / configure the priority of each channel using SLPP or LPP, respectively. The BS can convey the priority of the channel to the UE through RRC or DCI or MAC CE. In some examples, if the UE fails to access the highest priority channel, the UE can not transmit on all channels in the set. In some examples where non-contiguous RB sets are successfully accessed and the UE transmits on one of these channels, if non-contiguous RB sets are successfully accessed, the UE can transmit on one of these channels, where the priority of the channel is the highest among all successfully accessed channels. This can guarantee that the anchor UE can transmit SL-PRS and the target UE receives SL-PRS on the same RB set, thereby reducing the reception error.

[0170] In some embodiments, the SCI includes a field indicating RB set level resource allocation in order to let the Rx UE know the Tx UE’s frequency domain channel occupancy. In some embodiments, for SL positioning’s measurement reporting, the SL-PRS resource ID information cannot represent the real SL-PRS resource allocation. Therefore, the UE can associate its specific bandwidth information or RB set index with the SL positioning measurement. For the measurement reporting to the UE, the UE includes the channel information in the measurement report or location information report via SLPP; for the measurement reporting to the LMF, the UE includes the channel information in the measurement report or location information report via LPP. The channel information can be the bandwidth, the number of channel / RB sets, the location of channel / RB sets, the index of channel / RB sets.

[0171] In some embodiments, with respect to the case when the SCI / PSCCH and its associated SL-PRS are not close to each other, in other words, when there is at least a symbol level gap between the SCI / PSCCH and its associated SL-PRS, the UE successfully accesses the N1 channels for the SCI / PSCCH transmission, but only successfully accesses the N2 channels for the SL-PRS transmission, where N2 <= N1.

[0172] In some embodiments, if N2 < N1, the UE will not transmit the corresponding SL-PRS. This means that only when both the SCI / PSCCH transmission and the SL-PRS transmission access the same channels, the UE can transmit the SL-PRS. This can ensure that the SL-PRS frequency resource allocation indicated in the SCI or the mapping between the SCI and the SL-PRS should be kept accurate.

[0173] In some embodiments, if N2 < N1, the UE can still transmit the corresponding SL-PRS. In this case, the Tx UE can be informed that there can be different bandwidths for the SL-PRS bandwidth indicated in the SCI / PSCCH and the actual bandwidth of the SL-PRS. A 1-bit indicator can be included in the SCI. For example, when indicating “1”, the Rx UE does not expect a different or smaller bandwidth from the frequency resource allocation or the bandwidth according to the mapping between the SCI and the SL-PRS.

[0174] In some embodiments, the frequency domain allocation of the PSCCH is different from that of its associated SL-PRS. In some examples, all the channel / RB sets allocated for the PSCCH resource are successfully accessed. If only some of the channel / RB sets are sensed as free, the UE cannot transmit the PSCCH.

[0175] In some examples, the UE can transmit the corresponding SL-PRS only when successfully accessing the PSCCH and the SL-PRS. The bandwidth of the SL-PRS should be consistent with (e.g., equal to) the one indicated in the PSCCH or should be consistent with the mapping relationship between the PSCCH and the SL-PRS.

[0176] In some examples, even if the bandwidth of the SL-PRS is not consistent with the one indicated in the PSCCH or the mapping relationship between the PSCCH and the SL-PRS, the UE can still transmit the SL-PRS based on the rules, algorithms and standards (e.g., higher priority channel, contiguous RB set, etc.) described in the present examples.

[0177] In some embodiments, the first frequency location of the channel for SL positioning related transmission is configured by the BS via RRC signaling. The first frequency location is different from the second frequency location for at least DL transmission or UL transmission.

[0178] In some embodiments, the method 400 further includes transmitting, by the first UE, SL positioning related transmission on the plurality of channels in response to successfully accessing the plurality of channels. The method 400 further includes transmitting, by the first UE, SL positioning related transmission on one or more contiguous channels in response to successfully accessing the one or more channels. The method 400 further includes transmitting, by the first UE, SL positioning related transmission on one of the two or more non-contiguous channels in response to successfully accessing the two or more non-contiguous channels. The method 400 further includes transmitting SL positioning related transmission based on the multi-channel access result, wherein the number of channels is based on the frequency resources of the SL positioning related transmission. The method 400 further includes transmitting SL positioning related transmission based on the multi-channel access result. The transmission start time of the SL-PRS and the PSCCH can be the same or different.

[0179] In some embodiments, the first UE transmits the SL positioning related transmission in response to determining that the number of channels accessed by the first wireless communication device is greater than a threshold, wherein the threshold is configured by the LMF, the BS, the UE or pre-configured.

[0180] In some embodiments, the plurality of channels for transmitting the SL positioning related transmission have different priorities, wherein the priority of each channel can be configured by the LMF or the BS, the third UE or through pre-configuration.

[0181] In some embodiments, the measurement report or location information report of the first wireless communication device is transmitted to the third wireless communication device via SLPP or to the LMF via Long Term Evolution Positioning Protocol (LPP). The measurement report or location information report includes at least one of a SL-PRS bandwidth, a number of channels, a channel index or indicator, indicating a different bandwidth in a bandwidth used to transmit SL positioning related transmissions.

[0182] In some embodiments, in addition to dynamic channel access, the UE can also access one or more channels via a semi-static channel access procedure. Figure 18 is a diagram illustrating semi-static channel access according to various embodiments. For semi-static channel access, a period of duration T (e.g., FFP 1810) includes a COT duration 1820 at the beginning of the period and an idle duration 1830 at the end of the period.

[0183] In some embodiments, initiating a semi-static channel occupancy for SL positioning can include a semi-static channel occupancy initiated by a UE only, a semi-static channel occupancy initiated by a gNB or a UE, a semi-static channel occupancy initiated by a gNB only.

[0184] In some embodiments, a periodicity of semi-static channel access for SL positioning can be associated with SL-PRS configuration / features. In some examples, the occasions of SL-PRS transmissions are within the COT duration, not within the idle period. For example, a periodicity or resource reservation period of SL-PRS is associated with or mapped to a periodicity of semi-static channel access. The periodicity or resource reservation period of SL-PRS can be configured as an integer multiple or integer factor of the periodicity of semi-static channel access.

[0185] In some examples where the semi-static channel occupancy is initiated by a UE only, a location of the periodic COT is associated with or mapped to the SL-PRS transmission occasions (time domain). The time domain features of SL-PRS include at least one of a SL-PRS resource set slot offset, a SL-PRS resource slot offset, a SL-PRS resource symbol offset, a SL-PRS resource start slot number, a SL-PRS resource start symbol number, a SL-PRS periodicity or resource reservation period. For example, at least the transmitted SL-PRS resources and / or their related PSCCH are at the beginning of the FFP period.

[0186] In some examples, the channel occupancy is initiated by the UE only. Starting from an even-indexed radio frame, the UE can initiate periodic channel occupancy on one or more channels every T consecutive radio frames. In this case, only the channel occupancy time T that the UE can initiate is configured or pre-configured for the UE. For resource allocation scheme 1, the channel occupancy period T is configured or pre-configured by the BS via RRC or DCI or MAC CE. For resource allocation scheme 2, the UE selects its own SL-PRS transmission resources. In some examples, the UE is still within the coverage of the BS, and the channel occupancy period T that the UE can initiate is configured by the BS via RRC or determined by the UE itself based on its SL-PRS transmission needs. In some examples, the UE is out of the coverage of the BS, and the channel occupancy period T is determined by the UE itself based on its SL-PRS transmission needs. For resource allocation scheme 2, another UE (e.g., a server UE) can configure or pre-configure the semi-static channel occupancy period and send it to the UE via SLPP or PC5-RRC or SL MAC CE or SCI. At least the PSCCH and / or SL-PRS transmission occasions start from an even-indexed radio frame, configured or pre-configured or determined by the UE itself.

[0187] In some embodiments, the UE can initiate periodic channel occupancy on one or more channels every T starting from any frame or slot or symbol. In other words, there can be an offset between the starting point of the periodic channel occupancy and the even-indexed radio frame. For resource allocation scheme 1, the channel occupancy time T and the offset are configured by the gNB via RRC or DCI or MAC CE. For resource allocation scheme 2, the UE selects its own SL-PRS transmission resources. In some examples, the UE is still within the coverage of the BS, and the channel occupancy period T and the offset that the UE can initiate are either configured by the BS via RRC or determined by the UE itself based on its SL-PRS transmission needs. In some examples, the UE is out of the coverage of the BS, and the channel occupancy period T and the offset are determined by the UE itself based on its SL-PRS transmission needs. For resource allocation scheme 2, another UE (e.g., a server UE) can configure or pre-configure the time period and the offset of the semi-static channel occupancy and send it to the UE via SLPP or PC5-RRC or SL MAC CE or SCI.

[0188] In some embodiments where the UE transmits SL-PRS resources in resource allocation scheme 1, the LMF can recommend or configure the channel occupancy period and / or its offset to the UE via LPP. In some embodiments, the LMF can recommend or indicate or configure the channel occupancy period and / or the offset of the UE and send it to the BS via NRPPa. The BS can pass such information to the UE via RRC.

[0189] In some embodiments, the LMF or the BS can align the idle periods of different UEs. For example, different UEs can have different semi-static channel occupancy periods, and their idle periods can be located at different locations. To minimize / avoid LBT failure as much as possible, the LMF or the BS can align the locations of the idle periods of different UEs.

[0190] In some examples, the BS configures the semi-static channel access configuration (e.g., periodicity, starting time, idle period location) for different UEs via RRC or DCI or MAC CE. In some examples, the UE can request the BS to provide the aligned semi-static channel access configuration via RRC or DCI or MAC CE. In some examples, the UE can request the LPP to provide the aligned semi-static channel access configuration via LPP. In some examples, the LMF can send a request message via NRPPa to trigger the BS to provide the semi-static channel access configuration for the UE. In some examples, the BS can send the semi-static channel access configuration for different UEs to the LMF. In some examples, the LMF can resolve potential LBT failure by implementation, e.g., the LMF can change the starting time of the semi-static period of a UE to align with other UEs’ timing. In some examples, the LMF sends the recommended or modified semi-static channel access configuration for different UEs to the BS, and the BS determines the semi-static channel access configuration by itself and distributes it to the UEs. In some examples, the LMF can provide the semi-static channel access configuration to the UE via LPP. In some examples where the UE is under the coverage of different BSs, the LMF can send a request message to the BS and request the BS to semi-static channel access configure the UEs under the coverage / control of other BSs. In some examples, the BS can transmit the semi-static channel access configuration of the UEs in its own coverage to other BSs through the Xn interface. Upon receiving the semi-static channel access configuration of the user terminals in the coverage of other BSs, the BS can configure the timing of the semi-static channel access configuration to ensure that the idle periods of different user terminals overlap as much as possible.

[0191] In some embodiments, the UE (e.g., a server UE) can be used to align the idle periods of different UEs. Some embodiments involve out-of-coverage scenarios when the LMF or the BS cannot coordinate the semi-static channel access timing. In some examples, the UE configures the semi-static channel access configuration (e.g., periodicity, starting time, idle period location) for different UEs via SLPP or SL MAC CE or SCI. In some examples, the UE can request another UE to provide the aligned semi-static channel access configuration via SLPP or SL MAC CE or SCI. In some examples, the UE can send a request message via SLPP or SL MAC CE or SCI to trigger the UE to provide the semi-static channel access configuration.

[0192] Figure 19 is a diagram illustrating semi-static channel access of two UEs (UE 1 and UE 2) according to various embodiments. As shown, the periodicity of UE 2’s semi-static channel access is twice that of UE 1. For example, the length of UE 2’s FFP 1920 (one semi-static channel access period) is equal to two semi-static channel access periods of UE 1, including FFPs 1910 and 1920. Each of FFPs 1910 and 1920 includes a COT 1930 and an idle duration 1940. FFP 1920 includes a COT 1950 and an idle duration 1960. A common idle period 1970 exists in the idle duration 1940 of FFP 1920 and the idle duration 1960 of FFP 1920. The BS, LMF, or UE can attempt to increase the common idle period 1970 as much as possible. Figure 19

[0193] In some embodiments, the channel access procedure is semi-static and has a periodicity mapped to a configuration or characteristic of the SL-PRS. The configuration or characteristic of the SL-PRS includes at least one of an SL-PRS resource set slot offset, an SL-PRS resource slot offset, an SL-PRS resource symbol offset, an SL-PRS resource start slot number, an SL-PRS resource start symbol number, an SL-PRS periodicity, or a resource reservation period.

[0194] In some embodiments, the semi-static channel access configuration including the periodicity is determined by the first UE or configured by a UE (e.g., a third UE) via at least one of SLPP signaling, PC5-RRC signaling, a SL MAC CE, or a SCI, by the BS via at least one of RRC signaling, DCI, or a MAC CE, or by the LMF via LPP.

[0195] In some embodiments, the periodicity of the semi-static channel access includes a COT duration and an idle period, different UEs can have different semi-static channel access configurations, and the idle periods of different wireless communication devices are aligned by a UE (e.g., a third UE) via at least one of SLPP signaling, PC5-RRC signaling, a SL MAC CE, or a SCI, by the BS via at least one of RRC signaling, DCI, or a MAC CE, or by the LMF via LPP.

[0196] ​While various embodiments of the present solution have been described above, it should be understood that they have been presented by way of example only, and not limitation. Likewise, the various figures can depict example architectures or configurations, which provide an example framework for understanding the exemplary aspects and features of the present solution. However, it will be apparent that the present solution is not limited to the illustrated example architectures or configurations, but can be employed in a variety of alternative architectures and configurations. Additionally, as will be appreciated, one or more features of one or more embodiments can be combined with one or more features of another embodiment. Also, it will be appreciated that the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

[0197] It is also to be understood that any reference to an element or feature of a given example can be a component used in, or of, the example being described, and that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, "comprising", "containing", "including", "having" and like phrases are used herein in their open-ended, non-limiting sense to mean that the described feature, block, step, or the like can be present, but that other features, blocks, steps, or the like can not be present. As such, these phrases do not exclude the presence of additional features, blocks, steps, or the like.

[0198] Furthermore, those skilled in the art will appreciate that any of a wide variety of different technologies can be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, and symbols discussed above can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0199] Those skilled in the art will further appreciate that any of the various illustrative logical blocks, modules, processors, devices, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a number of logic

[0200] Furthermore, those of ordinary skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithms described in connection with the present disclosure can be implemented or performed with an integrated circuit (IC), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The logical blocks, modules, and circuits can further include antennas and / or transceivers to communicate in or with various components within a network or device. The general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. The processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration to perform the functions described herein.

[0201] If implemented in software, the functions can be stored or transmitted over as one or more instructions or code on a computer-readable medium. Therefore, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact discs (CD), laser discs, optical discs, digital versatile discs (DVD), and floppy disks where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0202] In this example, the term "module" as used herein refers to software, firmware, hardware, and any combination thereof to perform the associated functions described herein. Additionally, for purpose of discussion, the various modules are described as discrete modules; however, as would be apparent to one of ordinary skill in the art, two or more modules can be combined to form a single module that performs the associated functions according to the embodiments of the solution.

[0203] Additionally, memory or other storage, as well as communication components can be employed in embodiments of the solution. It will be appreciated that, for clarity, purposes the foregoing description has described embodiments of the solution with reference to different functional units and processors. However, it will be apparent that any appropriate distribution of functionality between different functional units, processing logic elements or domains can be used without detracting from the solution. For example, functionality illustrated to be performed by separate processing logic elements or controllers can be performed by the same processing logic element or controller. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0204] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed in this patent.

Claims

1. A wireless communication method, characterized in that, include: The first wireless communication device performs a channel access procedure for at least one channel; The first wireless communication device uses the at least one channel to transmit sidelink SL positioning-related transmissions with the second wireless communication device, wherein the SL positioning-related transmissions include at least one of an SL positioning reference signal SL-PRS or a physical shared control channel PSCCH corresponding to the SL-PRS.

2. The method according to claim 1, characterized in that, The channel access process includes Type 1 channel access, used to determine the SL location of the first wireless communication device in the unlicensed frequency band; In the SL positioning of the first wireless communication device, the channel access priority category CAPC used in channel access of type 1 corresponds to the Listen Before Talk (LBT) duration and the maximum channel occupancy time (COT). The CAPC corresponds to the configuration or feature of the SL-PRS.

3. The method according to claim 2, characterized in that, Also includes: The first wireless communication device receives an indication, configuration, or pre-configuration of the CAPC value or CAPC index corresponding to the CAPC, as the configuration or feature of the SL-PRS.

4. The method according to claim 3, characterized in that, At least one CAPC value is configured or pre-configured for each resource pool, each SL-PRS resource set, or each SL-PRS resource.

5. The method according to claim 3, characterized in that, It also includes at least one of the following: The first wireless communication device receives the CAPC from the base station BS via at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE); The first wireless communication device receives the CAPC from the second or third wireless communication device via at least one of Side Link Positioning Protocol (SLPP) signaling, PC5-RRC signaling, SL MAC CE, or Side Link Control Information (SCI); The first wireless communication device receives the CAPC from the location management function (LMF) via the Long Term Evolution (LPP) positioning protocol.

6. The method according to claim 3, characterized in that, Also includes: The first wireless communication device determines the CAPC value or the CAPC index using a mapping between the following: CAPC value or CAPC index; The configuration or features of the SL-PRS.

7. The method according to claim 6, characterized in that, The configuration or features of the SL-PRS include SL-PRS priority levels.

8. The method according to claim 6, characterized in that, The configuration or feature of the SL-PRS includes the duration of time-domain resources corresponding to the COT value in the CAPC table; The configuration of the duration of the time-domain resources includes at least one of the following: periodicity to be transmitted by the first wireless communication device, number of symbols in the time slot, repetition factor, time interval, and number of consecutive time slots / symbols.

9. The method according to claim 2, characterized in that, Also includes: The first wireless communication device receives the channel access priority category (CAPC) located by the SL of the first wireless communication device, wherein at least one of the following is included: The first wireless communication device receives the CAPC from the base station BS via at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE); The first wireless communication device receives the CAPC from the second or third wireless communication device via at least one of the Sidelink Positioning Protocol (SLPP) signaling, PC5-RRC signaling, SL MAC CE, or Sidelink Control Information (SCI); or The first wireless communication device receives the CAPC from the location management function (LMF) via the Long Term Evolution (LPP) positioning protocol.

10. The method according to claim 5 or 9, characterized in that, The first wireless communication device receives the CAPC from the LMF; and It also includes at least one of the following: The BS sends the CAPC and SL-PRS configuration corresponding to the CAPC to the LMF via the first New Radio Positioning Protocol (NRRPPa) signaling. The LMF receives information from multiple BSs and requests the multiple BSs to adjust the CAPC value via a second NRPPa signaling. The plurality of BSs adjust the CAPC value and send the adjusted configuration corresponding to the adjusted CAPC value to the LMF via a third NRPPa signaling; The LMF distributes the adjusted configuration to the UE via Long Term Evolution Positioning Protocol (LPP) signaling.

11. The method according to claim 2, characterized in that, Also includes: The first wireless communication device uses the CAPC value contained in at least one of the MAC CE, the Common Control Channel CCCH Service Data Unit SDU, the Dedicated Control Channel DCCH SDU, the MAC SDU, or the SL Shared Channel SL-SCH subheader to determine the CAPC value of the SL location-related transmission.

12. The method according to claim 1, characterized in that, Also includes: The first wireless communication device initiates channel occupancy for two or more SL transmissions by determining a unified CAPC value, wherein the SL transmission includes at least one of the SL-PRS or SL data transmission.

13. The method according to claim 1, characterized in that, Also includes: The first wireless communication device performs interference-free channel assessment (CCA) during the LBT duration based on the contention window (CW) size. and The first wireless communication device accesses one or more SL channels for SL positioning, with or without adjusting the CW size.

14. The method according to claim 13, characterized in that, The first wireless communication device accesses one or more SL channels without adjusting the CW size; and It also includes at least one of the following: Each channel access priority category CAPC value is associated with a fixed CW size; Each CAPC value is associated with two or more CW sizes, and the first wireless communication device randomly selects a candidate CW size from the two or more CW sizes to transmit the corresponding SL-PRS; Each CAPC value is associated with two or more CW sizes, which the first wireless communication device uses for the channel access procedure indicated or configured by at least one of the base station BS, the second wireless communication device, the third wireless communication device, or the LMF.

15. The method according to claim 13, characterized in that, Also includes: The first wireless communication device adjusts the CW size using the channel evaluation results.

16. The method according to claim 15, characterized in that, Also includes: The first wireless communication device receives the measurement results of the SL-PRS or the PSCCH of the second wireless communication device from the second wireless communication device via at least one of the Side Link Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) Control Element (CE), or Side Link Control Information (SCI). The first wireless communication device adjusts or maintains the CW size by comparing the measurement result of the SL-PRS or the measurement result of the PSCCH of the second wireless communication device with a measurement threshold.

17. The method according to claim 15, characterized in that, Also includes: The first wireless communication device receives from the second wireless communication device an indication of whether to adjust the CW size and adjustment information for adjusting the CW size via at least one of the Sidelink Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) control element (CE), or Sidelink Control Information (SCI).

18. The method according to claim 13, characterized in that, Each channel access priority category CAPC value or the configuration or characteristics of the SL-PRS is mapped to two or more CW sizes; and The method also includes one of the following: The first wireless communication device receives from the second wireless communication device an indication of whether to adjust the CW size and adjustment information for adjusting the CW size via at least one of Side Link Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) Control Element (CE) or Side Link Control Information (SCI). The first wireless communication device determines whether to adjust the CW size and the adjustment information for adjusting the CW size; The first wireless communication device receives from the base station BS an indication of whether to adjust the CW size and the adjustment information for adjusting the CW size via at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE). The first wireless communication device receives from the LMF via the Long Term Evolution Positioning Protocol (LPP) an indication of whether to adjust the CW size and adjustment information for adjusting the CW size.

19. The method according to claim 13, characterized in that, Also includes: The first wireless communication device adjusts the CW size by adjusting the Channel Access Priority Category (CAPC) value; and The method also includes one of the following: The first wireless communication device receives, via at least one of Side Link Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) Control Element (CE) or Side Link Control Information (SCI), an indication of whether to adjust the CAPC value and adjustment information for adjusting the CAPC value from the second wireless communication device. The first wireless communication device determines whether to adjust the CAPC value and the adjustment information for adjusting the CAPC value; The first wireless communication device receives from the base station (BS) an indication of whether to adjust the CAPC value and adjustment information for adjusting the CAPC value via at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE); or The first wireless communication device receives an instruction from the Location Management Function (LMF) via the Long Term Evolution (LPP) positioning protocol to indicate whether to adjust the CAPC value and the adjustment information for adjusting the CAPC value.

20. The method according to claim 19, characterized in that, The determination of whether to adjust the CAPC value and the adjustment information used to adjust the CAPC value are based on one of the following: LBT failure time, initial transmission or retransmission for SL positioning, and channel conditions.

21. The method according to claim 1, characterized in that, The channel access process includes Type 2 channel access, used to determine the SL location of the first wireless communication device in the unlicensed frequency band before the SL location-related transmission; as well as The method further includes: a first wireless communication device sensing the duration for which at least one sensing slot of the Listen-After-Talk (LBT) prior to the SL positioning-related transmission is idle, wherein the LBT duration is deterministic.

22. The method according to claim 21, characterized in that, Also includes: The first wireless communication device is determined to be capable of using type 2 channel access based on at least one of the following: duration of the SL location-related transmission, duty cycle, SL-PRS priority, channel access priority category (CAPC), and number of symbols within a periodicity or time slot.

23. The method according to claim 21, characterized in that, Also includes: The first wireless communication device receives Channel Occupancy Time (COT) sharing information for SL positioning from the second or third wireless communication device. The COT sharing information includes at least one of the following: COT time domain information, COT frequency domain information, one or more UE pair information, the first wireless communication device's Channel Access Priority Class (CAPC), the first wireless communication device's SL-PRS priority, a common COT indicator, and a group ID.

24. The method according to claim 23, characterized in that, The COT shared information is included in the side link control information (SCI), which includes a field indicating whether the reserved SL-PRS resources of the first wireless communication device can be used to transmit the SL-PRS, based on whether the reserved SL-PRS resources are within the COT initiated by the second wireless communication device. The new field in the SCI or the SL-PRS request field is used for the indication.

25. The method according to claim 23, characterized in that, The COT shared information is contained in at least one of the Media Access Control (MAC) Controller (CE) or Side Link Positioning Protocol (SLPP) signaling.

26. The method according to claim 23, characterized in that, It also includes at least one of the following: The CAPC value transmitted by the first wireless communication device in the SL positioning is equal to or less than the CAPC value used by the second or third wireless communication device to initiate the COT. The SL-PRS transmission priority value of the first wireless communication device is equal to or less than the SL-PRS transmission priority value of the second or third wireless communication device used to initiate the COT; The SL-PRS of the second or third wireless communication device is transmitted to the first wireless communication device; The SL-PRS of the first wireless communication device in the shared COT is transmitted to the second or third wireless communication device. The SL-PRS of the first wireless communication device and the SL-PRS of the third wireless communication device in the shared COT are transmitted to the same second wireless communication device.

27. The method according to claim 1, characterized in that, The base station (BS) initiates a Channel Occupancy Time (COT) and shares the COT with the first wireless communication device to perform the SL positioning-related transmission; and The SL positioning-related transmissions are scheduled or configured by the BS.

28. The method according to claim 27, characterized in that, The BS uses at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE) to share the COT with the first wireless communication device, wherein the information used to share the COT includes at least one of the following: An indicator that indicates whether the COT is used for SL positioning-related transmissions; The frequency domain of the COT; The time domain of the COT; Physical uplink control channel (PUCCH) feedback related indications; Channel access type or channel access priority category (CAPC); CP extension length related indicators.

29. The method according to claim 1, characterized in that, After successfully accessing the channel, the first wireless communication device shares its COT with the base station BS via uplink control information (UCI) to perform downlink transmission.

30. The method according to claim 1, characterized in that, The first frequency position of the channel used for the SL positioning-related transmission is configured by the base station BS via Radio Resource Control (RRC) signaling, wherein the first frequency position is different from the second frequency position used for at least downlink DL transmission or uplink UL transmission.

31. The method according to claim 1, characterized in that, The method further includes at least one of the following: In response to successful access to multiple channels, the SL positioning-related transmission is transmitted on the multiple channels; In response to successful access to the one or more channels, the SL positioning-related transmission is transmitted on one or more consecutive channels; In response to successful access to two or more discontinuous channels, the SL positioning-related transmission is transmitted on one of the two or more discontinuous channels; The SL positioning-related transmission is transmitted based on the multi-channel access result, wherein the number of channels is based on the frequency resources of the SL positioning-related transmission; The SL positioning-related transmission is based on the multi-channel access result, wherein the transmission start times of SL-PRS and PSCCH are the same or different.

32. The method according to claim 31, characterized in that, In response to determining that the number of channels accessed by the first wireless communication device is greater than a threshold, the first wireless communication device transmits the SL positioning-related transmission, wherein the threshold is configured or pre-configured by the location management function (LMF), the base station (BS), or the third wireless communication device.

33. The method according to claim 31, characterized in that, Multiple channels used for transmitting the SL location-related transmissions have different priorities, wherein the priority of each channel is configured by the location management function (LMF), the base station (BS), or the third wireless communication device, or is pre-configured.

34. The method according to claim 31, characterized in that, The measurement report or location information report of the first wireless communication device is transmitted to the third wireless communication device via the Side Link Positioning Protocol (SLPP) or to the Location Management Function (LMF) via the Long Term Evolution Positioning Protocol (LPP), wherein the measurement report or location information report includes at least one of the following: SL-PRS bandwidth; Number of channels; Channel Index; Indicators indicating different bandwidths in the bandwidth used to transmit the SL positioning-related transmissions.

35. The method according to claim 1, characterized in that, The channel access process is semi-static and has periodicity mapped to the configuration or characteristics of the SL-PRS, wherein the configuration or characteristics of the SL-PRS include at least one of the following: SL-PRS resource set slot offset, SL-PRS resource slot offset, SL-PRS resource symbol offset, SL-PRS resource start slot number, SL-PRS resource start symbol number, SL-PRS periodicity, and resource reservation period.

36. The method according to claim 35, characterized in that, The periodic semi-static channel access configuration is determined by the first wireless communication device or by the following configuration: A wireless communication device that uses at least one of the following: Sidelink Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) Control Element (CE), and Sidelink Control Information (SCI). A base station BS that uses at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI), and Media Access Control (MAC) control element (CE); or Location management function (LMF) via Long Term Evolution Positioning Protocol (LPP).

37. The method according to claim 35, characterized in that, The semi-static channel access period includes the COT duration and the idle period. Different UEs have different semi-static channel access configurations, and the idle periods of different wireless communication devices are aligned in the following way: A wireless communication device that uses at least one of the following: Sidelink Positioning Protocol (SLPP) signaling, PC5 Radio Resource Control (RRC) signaling, SL Media Access Control (MAC) Control Element (CE), or Sidelink Control Information (SCI). A base station BS that uses at least one of Radio Resource Control (RRC) signaling, Downlink Control Information (DCI) or Media Access Control (MAC) control element (CE); or Location management function (LMF) via Long Term Evolution Positioning Protocol (LPP).

38. A wireless communication device, characterized in that, It includes at least one processor and a memory, wherein the at least one processor is configured to read code from the memory and implement the method according to claim 1.

39. A computer program product, characterized in that, It includes computer-readable program medium code stored thereon, which, when executed by at least one processor, causes the at least one processor to implement the method according to claim 1.

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