Efficient positioning reference signal detection for sidelink positioning in unlicensed spectrum

Abstract

Exemplary embodiments of the present disclosure relate to an apparatus, method, device, and computer-readable medium for supporting efficient positioning reference signal detection for sidelink positioning in unlicensed spectrum. A first terminal device in a radio access network may be configured to initiate a first listen-before-talk procedure before transmitting a sidelink positioning reference signal in the unlicensed spectrum to a second terminal device in the radio access network during a sidelink positioning session, transmit positioning-related control information to the second terminal device in the licensed spectrum, and transmit a sidelink positioning reference signal in the unlicensed spectrum in response to successful completion of the first listen-before-talk procedure. The positioning-related control information includes instructions for the second terminal device to receive notification of whether the first listen-before-talk procedure was successful or to perform a second listen-before-talk procedure.

Description

[Technical Field]

[0001] Various exemplary embodiments described herein relate generally to communications technologies, and more particularly to devices, methods, apparatus, and computer-readable media that support efficient positioning reference signal (PRS) detection for sidelink positioning in unlicensed spectrum. [Background technology]

[0002] Abbreviations found in the specification and figures are defined below. 3GPP (registered trademark) 3rd Generation Partnership Project CCA Clear Channel Assessment COT Channel Occupancy Time CW Contention Window DMRS demodulation reference signal gNB Next Generation Node B LBT Listen Before Talk NR new radio PRS Positioning Reference Signal PSCCH Physical Sidelink Control Channel PSFCH Physical Sidelink Feedback Channel PSSCH Physical Sidelink Shared Channel Rx Receiver SL Side Link SCI Sidelink Control Information Tx transmitter UE User Equipment

[0003] Recently, 3GPP approved a study item on positioning enhancements, which includes sidelink positioning as an important part. Possible solutions for sidelink positioning include relative positioning, ranging, and absolute positioning. The study item considers extending sidelink positioning to unlicensed bands. Summary of the Invention

[0004] Generally, the exemplary embodiments of the present disclosure provide an efficient positioning reference signal detection solution for sidelink positioning in unlicensed spectrum.

[0005] In a first aspect, an exemplary embodiment of a first terminal device in a radio access network is provided. The first terminal device may comprise at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the first terminal device to at least: initiate a first listen-before-talk procedure prior to transmitting a sidelink positioning reference signal in an unlicensed spectrum to a second terminal device in the radio access network during a sidelink positioning session; transmit positioning-related control information to the second terminal device in a licensed spectrum; and transmit a sidelink positioning reference signal in the unlicensed spectrum in response to a successful completion of the first listen-before-talk procedure initiated by the first terminal device. The positioning-related control information may include instructions for the second terminal device to receive notification of whether the first listen-before-talk procedure initiated by the first terminal device was successful or to perform a second listen-before-talk procedure.

[0006] In a second aspect, an exemplary embodiment of a second terminal device in a radio access network is provided. The second terminal device may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the second terminal device to at least receive positioning-related control information in a licensed band via a sidelink from a first terminal device in the radio access network, and perform sidelink positioning reference signal detection in an unlicensed band at a timing determined based on the positioning-related control information. The positioning-related control information may include instructions for the second terminal device to receive notification of whether a first listen-before-talk procedure initiated by the first terminal device is successful or to perform a second listen-before-talk procedure.

[0007] Exemplary embodiments of a method, an apparatus, and a computer-readable medium are also provided, which generally correspond to the above-described exemplary embodiments of the device, and for convenience, a repeated description thereof will not be given here.

[0008] Other features of exemplary embodiments of the present disclosure and, preferably, will become apparent from the following description of specific embodiments when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of exemplary embodiments of the present disclosure. [Brief explanation of the drawings]

[0009] Some illustrative embodiments will now be described, by way of non-limiting examples, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram illustrating a communication network in which exemplary embodiments of the present disclosure may be implemented. [Figure 2A] FIG. 2A is a schematic diagram illustrating the channel occupancy period obtained by the listen-before-talk procedure. [Figure 2B] FIG. 2B is a schematic flow chart illustrating a Type 1 listen-before-talk procedure. [Figure 3] FIG. 3 is a schematic message flow diagram illustrating sidelink communication between multiple user equipments. [Figure 4] FIG. 4 is a schematic message flow diagram illustrating a process according to an exemplary embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic block diagram illustrating an apparatus according to an exemplary embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic block diagram illustrating an apparatus according to an exemplary embodiment of the present disclosure. [Figure 7] 7 is a schematic block diagram illustrating an apparatus according to an exemplary embodiment of the present disclosure. Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. Repetitive description of the same elements will be omitted. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the following, several exemplary embodiments will be described in detail with reference to the accompanying drawings. The following description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known circuits, techniques, and components are shown in block diagram form to avoid obscuring the described concepts and features.

[0011] As used herein, the term "network equipment" refers to any suitable entity or device capable of providing a cell or coverage through which terminal equipment can access a network or receive services. Network equipment may be generally referred to as a base station. As used herein, the term "base station" may refer to a Node B (Node B or NB), an evolved Node B (eNode B or eNB), or a gNB. A base station may be embodied as a macro base station, a relay node, or a low-power node such as a pico base station or femto base station. A base station may consist of multiple distributed network units, such as a central unit (CU), one or more distributed units (DUs), and one or more remote radio heads (RRHs) or remote radio units (RRUs). The number and functionality of these distributed units depends on the selected split-RAN architecture.

[0012] As used herein, the terms "terminal equipment" or "user equipment" (UE) refer to any entity or device capable of wireless communication with network equipment or with each other. Examples of terminal equipment include mobile phones, mobile terminals (MT), mobile stations (MS), subscriber stations (SS), portable subscriber stations (PSS), access terminals (AT), computers, wearable devices, in-vehicle communication devices, machine-type communication (MTC) devices, device-to-device communication (D2D) devices, vehicle-to-everything (V2X) devices, sensors, etc. The terms "terminal equipment" can be used interchangeably with UE, user equipment, mobile terminal, mobile station, or wireless equipment.

[0013] FIG. 1 illustrates an exemplary communication network 100 in which exemplary embodiments of the present disclosure may be implemented. The communication network 100 may be a radio access network (RAN), such as a 5G New Radio (NR) RAN. As illustrated in FIG. 1, the communication network 100 may include multiple user equipments (UEs) 110a-110c (each individually referred to as a UE 110 or collectively referred to as a UE 110) and a base station 120 that communicates with one or more of the multiple UEs 110a-110c. The base station 120 is illustrated as a 5G base station (gNB) but may also be implemented as other base stations, such as a Long Term Evolution (LTE) base station (eNB), a Beyond 5G base station, or a future base station. The base station 120 may communicate with one or more UEs 110 via an uplink (UL) channel over a Uu interface and a downlink (DL) channel. In some exemplary embodiments, the base station 120 may implement other radio access technologies to communicate with the one or more UEs 110.

[0014] The UEs 110 may be mobile phones, vehicle-mounted terminals, roadside units, etc. In addition to communicating with the base station 120, the UEs 110 may also communicate directly with each other, e.g., via a PC5 interface, referred to as sidelink (SL) communication. Multiple UEs 110 may each function as an SL transmit (Tx) UE, transmitting on the sidelink, or an SL receive (Rx) UE, receiving on the sidelink. A Tx UE may perform sidelink transmissions to one or more Rx UEs via unicast, groupcast, or broadcast, with or without network control. For example, a sidelink may be established between UEs 110 that are all in network coverage (in-coverage scenario), UEs 110 that are all out of network coverage (out-of-coverage scenario), or UEs 110 where one or more UEs are in network coverage and other UEs are out of network coverage (partial coverage scenario).

[0015] The UE 110 may use different bands for different sidelink communications. For example, the UE 110 may transmit a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH) in a licensed band (e.g., an LTE or NR band) and a sidelink reference signal (e.g., a sidelink positioning reference signal (SL-PRS)) in an unlicensed band. An unlicensed band may refer to any frequency band that does not require a license from an appropriate regulatory body, and the frequency band may be used by any device, not just devices that have a license to use a particular frequency band. Examples of unlicensed bands available worldwide include 2.4 GHz, 5 GHz, and 60 GHz.

[0016] Unlicensed spectrum may also be used for other communication systems. For example, the 2.4 GHz and 5 GHz frequency bands are used for Wi-Fi® communications. Considering coexistence with other systems, a Tx UE must perform a specific channel assessment procedure to evaluate whether a channel is available in the unlicensed spectrum before initiating a sidelink transmission in the unlicensed spectrum. To assess channel availability, a listen-before-talk (LBT) channel access mechanism is introduced. When a Tx UE attempts to initiate a sidelink transmission, an "extended" LBT procedure is performed to evaluate whether a channel is available during the contention window (CW). The "extended" LBT procedure is generally referred to as Type 1 LBT or LBT Cat. 4. If the channel is available during the contention window, the Tx UE acquires the "right" to access the channel for a certain period of time, denoted as the channel occupancy time (COT), immediately after the contention window. Figure 2A is a schematic diagram of the contention window (CW) and the channel occupancy time (COT). Once the Tx UE has acquired the COT, it can perform sidelink transmission.

[0017] 2B is a schematic flow chart illustrating a Type 1 LBT procedure 200. In the LBT procedure 200, the UE observes the channel as a number of consecutive clear channel assessment (CCA) slots, also called sensing slots. In sub-7 GHz, the duration of a CCA slot is T sl is 9 μs. The UE determines that the channel is idle / available in a CCA slot if the power measured during the CCA slot (i.e., the collected energy) is below a predetermined threshold.

[0018] Referring to FIG. 2B, at 210, the UE waits for a waiting period T dUpon detecting that the channel is idle for a waiting period T, the UE may initialize a backoff counter N for the Type 1 LBT procedure with a random number uniformly distributed between 0 and CW at 212. d is the period T f = 16 μs, followed immediately by consecutive m p slot period T sl can be configured as follows.

[0019] At 214, the UE may determine whether the backoff counter N is equal to zero. If the backoff counter N is equal to zero, the UE obtains the right to access the channel for the channel occupation time (COT) and may immediately send a sidelink transmission in the unlicensed spectrum.

[0020] If the backoff counter N is greater than zero at 214, the UE decrements the backoff counter N by one at 216 and counts up an additional slot period T sl If the channel is detected for an additional slot period T sl If the channel is idle for an additional slot period T, the process 200 returns to step 214. sl If the UE is busy (the collected energy is equal to or greater than the predetermined energy threshold) for an additional waiting period T d The process 200 continues to detect the channel until it is detected to be idle, after which the process 200 returns to step 214.

[0021] In a synchronous cellular communication system, transmission can only start at the beginning of a slot (e.g., an NR slot) or a symbol within a slot (e.g., an OFDM symbol within an NR slot). In 214, if the backoff counter N is equal to zero (i.e., the Type 1 LBT procedure has ended), the UE obtains the right to access the channel. In this embodiment, if the UE is about to start transmission at the beginning of a slot or symbol (the slot or symbol is after the Type 1 LBT procedure has ended), the UE performs an additional shortened / reduced LBT procedure (e.g., a waiting period T d (The UE checks whether the channel is idle for an additional period of time T). After the UE determines that the channel is idle for the above period, it can begin transmission at the beginning of the slot or symbol. In another embodiment, the UE additionally senses the channel when the UE is ready to transmit. The UE may sense the channel for at least a period T of the CCA slot. sl If the channel is detected as idle in , transmission can occur on the channel.

[0022] In the present disclosure, the Type 1 LBT procedure is considered to be completed or successful when the backoff counter of the Type 1 LBT procedure is decremented to 0. The UE performs the Type 1 LBT based on the Channel Access Priority Class (CAPC) associated with the sidelink transmission transmitted in the unlicensed spectrum. The aforementioned parameters CW, m for the Type 1 LBT procedure are used. p , T d , and COT may be determined based on CAPC. The UE obtains the COT upon successful completion of the Type 1 LBT procedure, and the obtained COT remains valid even if the UE pauses transmission. If the UE wants to start a new transmission within the COT, it must also perform a "reduced" (or shortened) LBT procedure. The "reduced" LBT procedure, commonly known as LBT Type 2, has the following variations: Type 2A (25μs LBT, also known as LBT Cat.2) For sidelink transmissions within the initiating device that has acquired the COT (if the gap between two sidelink transmissions is 25 μs or more, and for sidelink transmissions that follow other sidelink transmissions) Type 2B (16μs LBT, also known as LBT Cat.2) For Sidelink transmissions within an initiating device that has acquired the COT (only used for Sidelink transmissions that follow other Sidelink transmissions with a gap equal to 16 μs) Type 2C (without LBT, also known as LBT Cat.1) For a sidelink transmission that follows another sidelink transmission with a transmission gap of less than 16 μs, the allowed duration of the sidelink transmission is less than or equal to 584 μs.

[0023] The initiating UE (i.e., the UE that starts the sidelink transmission) can share the obtained COT with the intended recipient (responding UE). For this purpose, the initiating UE can inform the responding UE about the duration of the COT, e.g., via control signaling. The responding UE can then use this information to decide which type of LBT to apply when performing a transmission where the initiating UE is the intended recipient. If the responding UE's transmission falls outside the range of the COT or if the responding UE wants to make a new transmission to another UE, the responding UE needs to obtain a new COT using LBT type 1 with the appropriate CAPC.

[0024] 3 illustrates an example of sidelink communication 300 between multiple UEs. Referring to FIG. 3 , the first UE 110a may perform a Type 1 LBT procedure to obtain a first COT at 310 and then transmit a sidelink transmission via a PSCCH / PSSCH to the second UE 110b within the first COT at 312. The first UE 110a may also share the first COT with the second UE 110b via control signaling. Within the first COT, the second UE 110b may perform a “reduced” LBT (LBT Type 2) to check channel availability at 314 and transmit hybrid automatic repeat request (HARQ) feedback to the first UE 110a via a physical sidelink feedback channel (PSFCH) at 316 in response to the PSCCH / PSSCH transmission received from the first UE 110a. The PSFCH is introduced to enable HARQ feedback over the sidelink from the UE that is the intended recipient of a sidelink transmission (i.e., the Rx UE) to the UE that performed the sidelink transmission (i.e., the Tx UE). If the Rx UE successfully receives and decodes the sidelink transmission, it generates a positive HARQ acknowledgment (ACK) and sends the HARQ ACK on the PSFCH to the Tx UE to acknowledge successful reception of the sidelink transmission. If the Rx UE fails to receive or decode the sidelink transmission, it generates a negative HARQ acknowledgment (NACK) and sends a HARQ NACK on the PSFCH to the Tx UE to request a retransmission of the sidelink transmission.

[0025] If the second UE 110b wants to send a sidelink transmission to the third UE 110c, the second UE 110b may perform a Type 1 LBT procedure to obtain a second COT at 318 and transmit the sidelink transmission to the third UE 110c, for example, on the PSCCH / PSSCH at 320. The second UE 110b may also share the second COT with the third UE 110c via control signaling. Within the second COT, the third UE 110c may perform a Type 2 LBT procedure to check channel availability at 322 and transmit HARQ feedback on the PSFCH to the second UE 110b at 324 in response to the sidelink transmission received from the second UE 110b.

[0026] When operating in unlicensed spectrum, the listen-before-talk requirement creates uncertainty as to whether a transmission can be performed when intended. For example, in a sidelink positioning procedure, the Tx UE is uncertain about when it can transmit a positioning reference signal (PRS), and therefore the corresponding Rx UE needs to detect the PRS. To overcome the uncertainty in the timing of PRS detection, the Rx UE can apply continuous PRS sequence detection. However, this requires high power consumption. Another option for the Rx UE is to perform PRS sequence detection only in slots / symbols indicated by the Tx UE. However, in this case, the Tx UE may not be able to acquire the channel before the indicated slot / symbol, resulting in long latency.

[0027] According to one aspect of the present disclosure, an efficient PRS detection mechanism for sidelink positioning in an unlicensed spectrum is provided. In some exemplary embodiments, a Tx UE can dynamically determine an efficient method for an Rx UE to detect a sidelink PRS transmitted in the unlicensed spectrum. For example, if the delay between the PSSCH and the associated PSFCH is longer than the remaining time of the LBT procedure performed by the Tx UE for PRS transmission, the Tx UE can use a modified PSFCH to notify the Rx UE whether the LBT procedure performed by the Tx UE was successful. In another example, if the Tx UE and the Rx UE observe the same radio environment, the Tx UE can request the Rx UE to perform the same LBT procedure as the LBT procedure performed by the Tx UE to predict the timing of PRS transmission. The Tx UE can transmit positioning-related control information before the Tx UE acquires the right to transmit a PRS in the unlicensed spectrum by transmitting a PRS to the Rx UE in the unlicensed spectrum and transmitting positioning-related control information to the Rx UE in the licensed spectrum. The proposed mechanism enables the Rx UE to quickly detect PRS in unlicensed spectrum with low complexity and power consumption.

[0028] 4 illustrates a process 400 for sidelink PRS transmission and detection in an unlicensed spectrum in accordance with an exemplary embodiment of the present disclosure. Process 400 may be performed by a Tx UE transmitting a sidelink PRS and one or more Rx UEs receiving the sidelink PRS. The Tx UE and the Rx UE may include multiple means, modules, components, or elements for performing operations in process 400, and the means, modules, components, or elements may be implemented in various manners, including, but not limited to, software, hardware, firmware, or any combination thereof.

[0029] 4, at 410, the Tx UE 110a may perform a sidelink positioning establishment procedure with the Rx UE 110b in response to a request for sidelink positioning from higher layers. The sidelink positioning establishment request may be associated with a procedure for positioning the Tx UE 110a or the Rx UE 110b. During the sidelink positioning establishment procedure, the Tx UE 110a may determine whether the Tx UE 110a and the Rx UE 110b observe the same radio environment.

[0030] In an exemplary embodiment, the Tx UE 110 may determine whether the Tx UE 110a and the Rx UE 110b are in the same radio environment based on the distance between the Tx UE 110a and the Rx UE 110b. The Tx UE 110a may estimate a rough distance between the Tx UE 110a and the Rx UE 110b by utilizing a reference signal received from the Rx UE 110b, for example, a demodulation reference signal (DMRS) received on the PSSCH from the Rx UE 110b. If the distance is equal to or less than a configured threshold, the Tx UE 110a may determine that the Tx UE 110a and the Rx UE 110b are observing the same radio environment. During a sidelink positioning establishment procedure, the Tx UE 110a and the Rx UE 110b may exchange information via the PSSCH transmitted in the licensed band. Because the carrier is within the permitted band, the distance estimate is rough and not accurate enough for positioning, but is acceptable for estimating the radio environment.

[0031] In another exemplary embodiment, the Tx UE 110 may determine whether the Tx UE 110a and the Rx UE 110b are in the same radio environment based on channel measurements performed by the Tx UE 110a and the Rx UE 110b. During a sidelink positioning establishment procedure, the Tx UE 110a and the Rx UE 110b may negotiate the timing and method of measuring channels in the unlicensed spectrum and then measure channels in the unlicensed spectrum as negotiated. The Rx UE 110b may transmit its measurement results to the Tx UE 110a, for example, via a PSSCH in the licensed spectrum. If the measurement results of the Rx UE 110b are the same as the measurement results of the Tx UE 110a, the Tx UE 110a may determine that the Tx UE 110a and the Rx UE 110b are in the same radio environment. It should be noted that other solutions may be used to determine whether the Tx UE 110a and the Rx UE 110b are in the same radio environment, and the exemplary embodiment is not limited to the example in this embodiment.

[0032] At 412, Tx UE 110a may initiate a Type 1 LBT procedure. Before initiating the Type 1 LBT procedure, Tx UE 110a may determine parameters for the Type 1 LBT procedure. For example, Tx UE 110a may determine a contention window (CW) value, a waiting period T for the Type 1 LBT procedure, and a channel access priority class (CAPC) associated with a sidelink positioning reference signal (PRS). d , a channel occupation time (COT) value can be determined. The Type 1 LBT procedure can be performed as described above with reference to FIG. 2B, and for convenience, the description thereof will not be repeated here.

[0033] At 414, Tx UE 110a may select sidelink resources for transmission of positioning-related control information in the licensed band. In an exemplary embodiment, the positioning-related control information may be transmitted as part of sidelink control information (SCI). The SCI may have a two-stage SCI structure including a first-stage SCI carried on a PSCCH and a second-stage SCI carried on a PSSCH to support size differences between SCIs for various NR sidelink service types. Tx UE 110a may select PSCCH and / or PSSCH resources for transmission of the SCI including the positioning-related control information.

[0034] Two radio resource allocation modes can be configured for the Tx UE 110a. In the first mode, the network is responsible for sidelink resource allocation for the Tx UE 110a. The Tx UE 110a can transmit a sidelink scheduling request (SL-SR) to the base station 120, and the base station 120 can transmit a resource allocation to the Tx UE 110a in response to the received SL-SR. In the second mode, the Tx UE 110a can autonomously select sidelink resources from sidelink resource pool(s) configured for the Tx UE 110a. For example, the Tx UE 110a can first perform a sensing procedure on the configured sidelink resource pool(s) to obtain information on reserved resources and then select sidelink resources based on the sensing results.

[0035] In an exemplary embodiment, Tx UE 110a may perform operation 412 before operation 414, or may perform operations 412 and 414 in parallel. When sidelink resources for transmission of positioning-related control information are selected, the Type 1 LBT procedure may still be in progress. In another exemplary embodiment, Tx UE 110a may perform operation 412 after operation 418. Tx UE 110a may initiate the Type 1 LBT procedure after transmitting positioning-related control information to Rx UE 110b using the selected sidelink resources in the licensed band.

[0036] At 416, the Tx UE 110a may determine an efficient method of sidelink PRS detection for the Rx UE 110b. As described above, due to the LBT procedure, it is uncertain when the Tx UE 110a will transmit the sidelink PRS. The Tx UE 110a may dynamically determine efficient PRS detection for the Rx UE 110b based on, for example, at least one of the following: a progress status of the Type 1 LBT procedure initiated at the Tx UE 110a, a delay between the sidelink resource selected for transmission of positioning-related control information and the physical sidelink feedback channel (PSFCH) resource associated with the selected sidelink resource, the radio environment of the Tx UE 110a and the Rx UE 110b, or additional factors.

[0037] In an exemplary embodiment, if the delay between the sidelink resource selected for transmission of positioning-related control information and the PSFCH resource associated with the selected sidelink resource is longer than the estimated remaining time of the Type-1 LBT procedure initiated at Tx UE 110a, Tx UE 110a may estimate that the Type-1 LBT procedure will finish before the HARQ feedback is transmitted on the PSFCH. Tx UE 110a may then decide to reuse the PSFCH resource to inform Rx UE 110 whether the Type-1 LBT procedure was successful or not. The estimated remaining time of the Type-1 LBT procedure is determined as a CCA sensing slot period Tsl At least n times (n×T sl ), where n is the current value of the back-off counter N. The delay between the selected sidelink resource and the associated PSFCH resource may be determined from a PSSCH-to-PSFCH time gap parameter K that is configured via the information element sl-MinTimeGapPSFCH in the Tx UE 110a and the Rx UE 110b. For example, for a selected sidelink resource having its last symbol in slot s, the associated PSFCH resource is expected in slot s+a, where a is the smallest integer greater than or equal to K.

[0038] In this embodiment, external interference may also be considered when the Tx UE 110a determines whether to reuse the PSFCH to notify the Rx UE 110b of whether the Type-1 LBT procedure was successful. When there is little or sporadic external interference, the Rx UE 110b has a high probability of successfully receiving the sidelink transmission from the Tx UE 110a. Therefore, the Rx UE 110b does not need to use the PSFCH to confirm successful reception of the sidelink transmission, and the Tx UE 110a can reuse the PSFCH to notify the Rx UE 110b of whether the LBT procedure initiated by the Tx UE 110a was successful. Also, when there is little or sporadic external interference, the channel is idle most of the time within the delay period.

[0039] In an exemplary embodiment, when Tx UE 110a and Rx UE 110b are in the same radio environment, Tx UE 110a may determine to instruct Rx UE 110b to perform a Type 1 LBT procedure to predict the timing of PRS transmission from Tx UE 110a, at 416. Rx UE 110b may perform a Type 1 LBT procedure synchronized with the Type 1 LBT procedure performed by Tx UE 110a, which will be described in more detail below. For convenience of explanation, the LBT procedure performed by Tx UE 110a will be referred to as a first LBT procedure, and the LBT procedure performed by Rx UE 110b will be referred to as a second LBT procedure.

[0040] At 418, the Tx UE 110a may transmit positioning-related control information to the Rx UE 110b using the selected sidelink resources in the licensed band. As described above, the positioning-related control information may be included in sidelink control information (SCI), and the positioning-related control information may be transmitted to the Rx UE 110b before the first LBT procedure initiated by the Tx UE 110a is completed.

[0041] In response to the determination at operation 416, the positioning-related control information may include instructions for Rx UE 110b to receive notification of whether the first LBT procedure was successful or instructions for Rx UE 110b to perform a second LBT procedure. The instructions for Rx UE 110b to perform the second LBT procedure may include one or more parameters related to the first LBT procedure performed by Tx UE 110a. In one example, the one or more parameters related to the first LBT procedure may include, for example, at least one of a start time or duration of the first LBT procedure, a current value of a back-off counter for the first LBT procedure, a waiting period for the first LBT, an energy threshold for the first LBT procedure, or a channel access priority class for the first LBT procedure.

[0042] If the positioning-related control information transmitted at 418 includes an instruction for Rx UE 110b to perform a second LBT procedure, Rx UE 110b may perform the second LBT procedure at 420. UE 110b may perform the second LBT procedure using one or more parameters of the first LBT procedure such that the first and second LBT procedures are performed synchronously with each other. For example, Rx UE 110b may start a back-off counter N of the second LBT procedure using a current back-off counter value of the first LBT procedure.

[0043] At 422a, the first LBT procedure performed by Tx UE 110a is completed successfully. When Rx UE 110b is instructed to perform a second LBT procedure at 418, because Tx UE 110a and Rx UE 110b are in the same radio environment and the second LBT procedure is performed synchronously with the first LBT procedure, the second LBT procedure performed by Rx UE 110b also simultaneously completes successfully at 422b.

[0044] Upon successful completion of the second LBT procedure performed at the Rx UE 110b, the Rx UE 110b may determine 423 the timing of sidelink positioning reference signal (PRS) detection. In one example, the Rx UE 110b may determine to perform sidelink PRS detection in the unlicensed spectrum immediately after the successful completion of the second LBT procedure. In another example, the Rx UE 110b may determine to start performing sidelink PRS detection in the unlicensed spectrum at the beginning of a slot (e.g., an NR slot) or a symbol within a slot (e.g., an OFDM symbol within an NR slot). The slot or symbol is after the successful completion of the second LBT procedure. Furthermore, because the Tx UE 110a and the Rx UE 110b are in the same radio environment, the Rx UE 110b may perform an additional shortened / reduced LBT procedure (e.g., when the channel is in a waiting period T ) immediately before the slot or symbol. d After the Rx UE 110b determines that the channel is idle for the above period, it may start performing sidelink PRS detection in the unlicensed spectrum at the beginning of the slot or symbol.

[0045] If Tx UE 110a instructs Rx UE 110b to receive a notification of whether the first LBT procedure was successful at 418, Rx UE 110b recognizes that the PSFCH resource associated with transmitting positioning-related control information is used to convey the notification, in which case Rx UE 110b may not transmit HARQ feedback to Tx UE 110a on the PSFCH resource associated with the positioning-related control information. Instead, Rx UE 110b receives the notification sent from Tx UE 110a on the PSFCH resource at 424.

[0046] Because the delay between the transmission of the positioning-related control information and the associated PSFCH resource is longer than the estimated remaining time of the first LBT procedure initiated by Tx UE 110a, the first LBT procedure may have already completed successfully when Tx UE 110a sends a notification on the PSFCH resource to Rx UE 110b. Tx UE 110a then sends a HARQ ACK on the PSFCH resource to Rx UE 110b, and Rx UE 110b can determine from the HARQ ACK that the first LBT procedure was successful.

[0047] For example, if the first LBT procedure has not yet finished at the timing of the PSFCH resource because the channel is busy in the sensing slot and Tx UE 110a must sense that the channel is idle for an additional waiting period, Tx UE 110a may send a HARQ NACK on the PSFCH resource to Rx UE 110b. Rx UE 110b may determine from the HARQ NACK that the first LBT procedure has not finished successfully.

[0048] When the notification represented by the HARQ feedback is received on the PSFCH, the Rx UE 110b may determine 425 the timing of sidelink positioning reference signal (PRS) detection based on the received notification. In one example, if the received notification indicates that the first LBT procedure initiated by the Tx UE 110a has completed successfully, the Rx UE 110b may determine to immediately perform sidelink PRS detection in the unlicensed spectrum. In another example, if the received notification indicates that the first LBT procedure initiated by the Tx UE 110a has completed successfully, the Rx UE 110b may determine to start performing sidelink PRS detection in the unlicensed spectrum at the start of a slot (e.g., an NR slot) or a symbol within a slot (e.g., an OFDM symbol within an NR slot), the slot or symbol being after the notification is received at the Rx UE 110b. If the received notification indicates that the first LBT procedure initiated by Tx UE 110a has not yet completed, Rx UE 110b may determine that it does not detect the sidelink PRS transmitted from Tx UE 110a in the unlicensed spectrum. In this case, operations 418, 424, and 425 may be repeatedly performed until the first LBT procedure is successfully completed.

[0049] Although the PSFCH resource associated with the positioning-related control information is used to transmit the LBT termination notification in the above exemplary embodiment, the present disclosure is not limited thereto. In the exemplary embodiment, the positioning-related control information may further include a resource allocation for transmitting the LBT termination notification. The Rx UE 110b may use the PSFCH resource to confirm receipt of the positioning-related control information as usual, and the Tx UE 110a may transmit the LBT termination notification to the Rx UE 110b based on the resource allocation.

[0050] In response to the indication that the first LBT procedure has been successfully completed, or in response to the indication that the second LBT procedure has been successfully completed, the Rx UE 110b may initiate 426 detection for sidelink PRS in the unlicensed spectrum.

[0051] In response to the first LBT procedure successfully completing, the Tx UE 110a may transmit 428 a sidelink PRS in the unlicensed spectrum to the Rx UE 110b. In an example embodiment, the Tx UE 110a may transmit the sidelink PRS periodically during the channel occupation time (COT) obtained through the first LBT procedure.

[0052] At 430, Rx UE 110b may transmit a measurement report related to the sidelink PRS to Tx UE 110a. Rx UE 110b may transmit the measurement report in the licensed band or the unlicensed band. Before transmitting the measurement report in the unlicensed band, Rx UE 110b may perform a Type 2 LBT procedure to confirm channel availability if the measurement report transmission is within the COT shared by Tx UE 110a, or perform a new Type 1 LBT procedure to obtain a new COT if the measurement report transmission is after the COT shared by Tx UE 110a.

[0053] In the above exemplary embodiment, the Tx UE 110a can dynamically determine an efficient sidelink PRS detection for the Rx UE 110b, and thus the Rx UE can quickly detect the sidelink PRS in the unlicensed spectrum with reduced complexity and power consumption. The PSFCH may be reused to notify the Rx UE that the LBT procedure has been completed at the Tx UE, so that the signaling overhead between the Tx UE and the Rx UE is not significantly increased.

[0054] In another exemplary embodiment, the first LBT procedure (e.g., a Type 1 LBT procedure) may end before the preparation of positioning-related control information. At 418, the Tx UE 110a may transmit positioning-related control information to the Rx UE 110b using the selected sidelink resource in the licensed band indicating that the first LBT procedure has ended. The Rx UE 110b may determine the timing of sidelink positioning reference signal (PRS) detection based on the positioning-related control information. In one example, the Rx UE 110b may determine to perform sidelink PRS detection in the unlicensed band immediately after receiving the positioning-related control information. In another example, the Rx UE 110b may determine to start performing sidelink PRS detection in the unlicensed band at the start of a slot (e.g., an NR slot) or a symbol within a slot (e.g., an OFDM symbol within an NR slot). The slot or symbol is after the Rx UE 110b receives the positioning-related control information. Furthermore, when the Tx UE 110a and the Rx UE 110b are in the same radio environment, the Rx UE 110b may perform an additional shortened / reduced LBT procedure (e.g., when the channel is short-circuited for a waiting period T d After the Rx UE 110b has confirmed that the channel is idle for the above period, it may start performing sidelink PRS detection in the unlicensed spectrum at the beginning of the slot or symbol.

[0055] In another exemplary embodiment, the first LBT procedure is a Type 2 LBT procedure, and the first LBT procedure is initiated after operation 418. At 418, the Tx UE 110a may transmit positioning-related control information to the Rx UE 110b using selected sidelink resources in the licensed band indicating that the first LBT procedure is a Type 2 LBT procedure. The Rx UE 110b may determine the timing of sidelink positioning reference signal (PRS) detection based on the positioning-related control information. In one example, the Rx UE 110b may determine to perform sidelink PRS detection in the unlicensed band immediately after receiving the positioning-related control information. In another example, the Rx UE 110b may determine to start performing sidelink PRS detection in the unlicensed band at the start of a slot (e.g., an NR slot) or a symbol within a slot (e.g., an OFDM symbol within a slot). The slot or symbol is after the Rx UE 110b receives the positioning-related control information. Furthermore, if the Tx UE 110a and the Rx UE 110b are in the same radio environment, the Rx UE 110b may perform an additional shortened / reduced LBT procedure (e.g., Type 2 LBT) immediately before a slot or symbol. The Rx UE 110b may start performing sidelink PRS detection in the unlicensed spectrum at the beginning of a slot or symbol after verifying that the channel is idle.

[0056] 5 is a schematic block diagram illustrating an apparatus 500 according to an exemplary embodiment of the present disclosure. The apparatus 500 may be implemented in a terminal device, such as a Tx UE 110a, to perform operations related to the Tx UE 110a, as described above. Since the operations related to the Tx UE 110a have been described in detail with reference to FIGS. 1 to 5, the blocks of the apparatus 500 will be briefly described here, and reference may be made to the above description for details.

[0057] As shown in FIG. 5 , the apparatus 500 may include first means 510, second means 520, and third means 530. The first means 510 may initiate a first listen-before-talk (LBT) procedure before the Tx UE 110a transmits a sidelink positioning reference signal (PRS) to the Rx UE 110b in an unlicensed spectrum during the sidelink positioning session. The second means 520 may transmit positioning-related control information to the Rx UE 110b in a licensed spectrum. The positioning-related control information may include an instruction for the Rx UE 110b to receive notification of whether the first LBT procedure initiated by the Tx UE 110a is successful or to perform a second LBT procedure. The third means 530 may transmit the sidelink PRS in the unlicensed spectrum in response to successful completion of the first LBT procedure initiated by the Tx UE 110a.

[0058] In an exemplary embodiment, the instruction for Rx UE 110b to perform the second LBT procedure may include one or more parameters related to the first LBT initiated by Tx UE 110a so that Rx UE 110b can perform the second LBT procedure synchronously with the first LBT procedure performed by Tx UE 110a. The one or more parameters related to the first LBT procedure may include at least one of a start time or duration of the first LBT procedure, a back-off counter value for the first LBT procedure, a waiting period for the first LBT procedure, an energy threshold for the first LBT procedure, or a channel access priority class for the first LBT procedure.

[0059] In an exemplary embodiment, the positioning-related control information is transmitted before the first LBT procedure ends.

[0060] In an exemplary embodiment, apparatus 500 may further comprise fourth means 540 and fifth means 550. The fourth means 540 may select a sidelink resource for transmitting positioning-related control information to Rx UE 110b. The fifth means 550 may determine whether to notify Rx UE 110b of whether the first LBT procedure was successful or instruct Rx UE 110b to perform a second LBT procedure based on at least one of a progress of the first LBT procedure, a delay between the selected sidelink resource and a sidelink feedback channel resource associated with the selected sidelink resource, or radio environments of Tx UE 110a and Rx UE 110b.

[0061] In an example embodiment, the fifth means 550 may determine to notify the Rx UE 110b whether the first LBT procedure was successful or not when a delay between the selected sidelink resource and a sidelink feedback channel resource associated with the selected sidelink resource is longer than an estimated remaining time of the first LBT procedure.

[0062] In an exemplary embodiment, the fifth means 550 may determine to instruct the Rx UE 110b to perform the second LBT procedure when the Tx UE 110a and the Rx UE 110b are in the same radio environment.

[0063] In an example embodiment, apparatus 500 may further comprise sixth means 560 for, when the positioning-related control information includes an instruction for Rx UE 110b to receive the notification, sending a notification of whether the first LBT procedure was successful or not over a sidelink feedback channel resource associated with the positioning-related control information to Rx UE 110b.

[0064] In an exemplary embodiment, apparatus 500 may further comprise seventh means 570 for determining whether Tx UE 110a and Rx UE 110b are in the same radio environment before transmitting the positioning-related control information. In one example, seventh means 570 determines that Tx UE 110a and Rx UE 110b are in the same radio environment if a distance between Tx UE 110a and Rx UE 110b is less than or equal to a threshold or if Tx UE 110a and Rx UE 110b obtain the same measurement result through unlicensed spectrum measurement.

[0065] In the exemplary embodiment, the first LBT procedure performed at Tx UE 110a is a Type 1 LBT procedure, and the second LBT procedure performed at Rx UE 110b is a Type 1 LBT procedure.

[0066] 6 is a schematic block diagram illustrating an apparatus 600 according to an exemplary embodiment of the present disclosure. The apparatus 600 may be implemented in a terminal device, such as the Rx UE 110b, to perform operations related to the Rx UE 110b, as described above. Since the operations related to the Rx UE 110b have been described in detail with reference to FIGS. 1 to 5, the blocks of the apparatus 600 will be briefly described here, and reference may be made to the above description for details.

[0067] 6, the apparatus 600 may comprise first means 610 for receiving positioning-related control information from the Tx UE 110a via a sidelink in a licensed band, and second means 620 for performing sidelink positioning reference signal (PRS) detection in an unlicensed band at a timing determined based on the positioning-related control information. The positioning-related control information may include instructions for the Rx UE 110b to receive notification of whether a first LBT procedure initiated by the Tx UE 110a is successful or to perform a second LBT procedure.

[0068] In an example embodiment, the apparatus 600 may further comprise: third means 630 for receiving, on a sidelink feedback channel resource associated with the positioning-related control information, a notification of whether the first LBT procedure initiated by the Tx UE 110a was successful, when the positioning-related control information includes an instruction for the Rx UE 110b to receive the notification; and fourth means 640 for determining a timing of sidelink PRS detection, when the received notification indicates that the first LBT procedure initiated by the Tx UE 110a was successful.

[0069] In an exemplary embodiment, the apparatus 600 may further comprise: a fifth means 650 for performing a second LBT procedure when the positioning-related control information includes an instruction for the Rx UE 110b to perform the second LBT procedure; and a sixth means 660 for determining timing of sidelink PRS detection when the performed second LBT procedure at the Rx UE 110b is successful. The instruction for the Rx UE 110b to perform the second LBT procedure may include one or more parameters related to the first LBT procedure initiated by the Tx UE 110a. In an exemplary embodiment, the one or more parameters related to the first LBT procedure may include at least one of a start time or duration of the first LBT procedure, a back-off counter value of the first LBT procedure, a waiting period of the first LBT procedure, an energy threshold of the first LBT procedure, or a channel access priority class of the first LBT procedure.

[0070] In the exemplary embodiment, the first LBT procedure initiated by Tx UE 110a is a Type 1 LBT procedure, and the second LBT procedure performed at Rx UE 110b is a Type 1 LBT procedure.

[0071] 7 is a schematic block diagram of a device 700 according to an exemplary embodiment of the present disclosure. The device 700 may be implemented as the Tx UE 110a and / or the Rx UE 110b described above.

[0072] Referring to FIG. 7, device 700 may include one or more processors 711, one or more memories 712, and one or more transceivers 713 interconnected via one or more buses 714. The one or more buses 714 may be an address bus, a data bus, or a control bus and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, fiber, optical, or other optical communication equipment. Each of the one or more transceivers 713 may include a receiver and a transmitter connected to one or more antennas 716. Device 700 may wirelessly communicate with network equipment or terminal equipment via the one or more antennas 716. The one or more memories 712 may include instructions 715 that, when executed by the one or more processors 711, cause device 700 to perform operations related to Tx UE 110a and / or operations related to Rx UE 110b, as described above.

[0073] The one or more processors 711 may be of any suitable type suitable for the local technology network and may include one or more of a general-purpose processor, a special-purpose processor, a microprocessor, a digital signal processor (DSP), one or more processors of a processor-based multi-core processor architecture, and special-purpose processors such as those developed based on field programmable gate arrays (FPGAs) and application-specific integrated circuits (ASICs). The one or more processors 711 may be configured to control and cooperate with other elements of device 700 and to implement the procedures described above.

[0074] The one or more memories 712 may include at least one storage medium in various forms, such as volatile and / or nonvolatile media. Volatile memory may include, for example, but is not limited to, random access memory (RAM) or cache. Nonvolatile memory may include, for example, but is not limited to, read-only memory (ROM), hard disk, flash memory, etc. Furthermore, the one or more memories 712 may include, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof.

[0075] Some exemplary embodiments further provide computer program code or instructions that, when executed by one or more processors, can cause a device or apparatus to perform the procedures described above. The computer program code or instructions for carrying out the procedures of the exemplary embodiments can be written in any combination of one or more programming languages. The computer program code or instructions can be provided to one or more processors or controllers of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and, when executed by the processors or controllers, cause the specific functions / operations in the flowcharts and / or block diagrams to be performed. The program code or instructions can be executed entirely on the machine, partially on the machine as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0076] Some exemplary embodiments further provide a non-transitory computer program product or a non-transitory computer-readable medium having computer program code or instructions stored therein. As used herein, the term "non-transitory" refers to the medium itself (i.e., tangible, not a signal) as opposed to the permanent limitation of data storage (e.g., RAM vs. ROM). A non-transitory computer-readable medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable medium includes, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More specific examples of computer-readable storage media include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0077] It will be understood that the blocks in the figures may be implemented in various manners, including software, hardware, firmware, or any combination thereof. In some embodiments, one or more blocks may be implemented using software and / or firmware, e.g., machine-executable instructions stored on a storage medium. In addition to or in lieu of machine-executable instructions, some or all of the blocks in the figures may be implemented at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include FPGAs (field programmable gate arrays), ASICs (application-specific integrated circuits), ASSPs (application-specific standard products), SOCs (systems on chips), CPLDs (complex programmable logic devices), etc.

[0078] Furthermore, although operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order illustrated, or sequentially, or to perform all of the illustrated operations, to achieve desirable results. In certain situations, multitasking and parallel processing may be preferred. Similarly, while several specific implementation details are included in the above description, these should not be construed as limiting the scope of the disclosure, but rather as descriptions of features that may be unique to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

[0079] Although the present subject matter has been described in language specifying structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not limited to the particular features or acts described above. Rather, the particular features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first terminal device in a radio access network, at least one processor; When executed by the at least one processor, the method causes the first terminal device to initiating a first listen-before-talk procedure before transmitting a sidelink positioning reference signal to a second terminal device in the radio access network in an unlicensed spectrum during a sidelink positioning session; transmitting, in a permitted band, positioning-related control information to the second terminal device, the positioning-related control information including an instruction for the second terminal device to receive notification of whether the first listen-before-talk procedure initiated by the first terminal device is successful or to perform a second listen-before-talk procedure; transmitting the sidelink positioning reference signal in the unlicensed spectrum in response to successful completion of the first listen-before-talk procedure initiated by the first terminal device; at least one memory storing instructions for executing the a first terminal device including:

2. The first terminal device according to claim 1 , wherein the positioning-related control information is transmitted before the first listen-before-talk procedure initiated by the first terminal device is terminated.

3. The at least one memory, when executed by the at least one processor, causes the first terminal device to transmitting, to the second terminal device, the notification of whether the first listen-before-talk procedure initiated by the first terminal device has been successful or not, on a sidelink feedback channel resource associated with the positioning-related control information, if the positioning-related control information includes the instruction for the second terminal device to receive the notification of whether the first listen-before-talk procedure initiated by the first terminal device has been successful or not; The first terminal device of claim 1 , further storing instructions for causing the first terminal device to execute the following:

4. 2. The first terminal device of claim 1, wherein the instructions for the second terminal device to perform the second listen-before-talk procedure include one or more parameters related to the first listen-before-talk procedure initiated by the first terminal device.

5. The one or more parameters associated with the first listen-before-talk procedure initiated by the first terminal device are: a start time or duration of the first listen-before-talk procedure; a back-off counter value for the first listen-before-talk procedure; a waiting period for the first listen-before-talk procedure; an energy threshold of the first listen-before-talk procedure, or a channel access priority class for the first listen-before-talk procedure; The first terminal device according to claim 4, comprising at least one of:

6. The at least one memory, when executed by the at least one processor, causes the first terminal device to selecting a sidelink resource for transmitting the positioning-related control information to the second terminal device; and determining whether to notify the second terminal device whether the first listen-before-talk procedure initiated by the first terminal device has been successful or to instruct the second terminal device to perform the second listen-before-talk procedure based on at least one of a progress status of the first listen-before-talk procedure initiated by the first terminal device, a delay between the selected sidelink resource and a sidelink feedback channel resource associated with the selected sidelink resource, or a radio environment of the first terminal device and the second terminal device; The first terminal device of claim 1 , further storing instructions for causing the first terminal device to execute the following:

7. 7. The first terminal device of claim 6, wherein the first terminal device decides to notify the second terminal device whether the first listen-before-talk procedure initiated by the first terminal device has been successful if the delay between the selected sidelink resource and the sidelink feedback channel resource associated with the selected sidelink resource is longer than an estimated remaining time of the first listen-before-talk procedure initiated by the first terminal device.

8. The first terminal device according to claim 6, wherein the first terminal device determines to instruct the second terminal device to perform the second listen-before-talk procedure when the first terminal device and the second terminal device are in the same wireless environment.

9. The at least one memory, when executed by the at least one processor, causes the first terminal device to determining whether the first terminal device and the second terminal device are in the same radio environment before transmitting the positioning-related control information; The first terminal device according to claim 8 , further storing instructions for causing the first terminal device to execute the following:

10. The first terminal device When the distance between the first terminal device and the second terminal device is equal to or less than a threshold value, or When the first terminal device and the second terminal device obtain the same measurement result by measuring the unlicensed band, The first terminal device according to claim 9, wherein the first terminal device and the second terminal device are determined to be in the same radio environment.

11. 2. The first terminal device according to claim 1, wherein the first listen-before-talk procedure initiated by the first terminal device is a type 1 listen-before-talk procedure, and the second listen-before-talk procedure performed in the second terminal device is a type 1 listen-before-talk procedure.

12. A second terminal device in a radio access network, at least one processor; When executed by the at least one processor, the method causes the second terminal device to receiving positioning-related control information via a sidelink in a licensed band from a first terminal device in the radio access network, the positioning-related control information including an instruction for the second terminal device to receive a notification of whether a first listen-before-talk procedure initiated by the first terminal device was successful or to perform a second listen-before-talk procedure; performing sidelink positioning reference signal detection in an unlicensed band at a timing determined based on the positioning-related control information; at least one memory storing instructions for executing the A second terminal device comprising:

13. The at least one memory, when executed by the at least one processor, causes the second terminal device to receiving, when the positioning-related control information includes an instruction for the second terminal device to receive the notification, a notification on a sidelink feedback channel resource associated with the positioning-related control information of whether the first listen-before-talk procedure initiated by the first terminal device was successful; determining the timing for detecting sidelink positioning reference signals if the received notification indicates that the first listen-before-talk procedure initiated by the first terminal device is successful; and The second terminal device of claim 12, further storing instructions to cause the second terminal device to execute the following:

14. The at least one memory, when executed by the at least one processor, causes the second terminal device to performing the second listen-before-talk procedure when the positioning-related control information includes the instruction to cause the second terminal device to perform the second listen-before-talk procedure, and the instruction to cause the second terminal device to perform the second listen-before-talk procedure includes one or more parameters related to the first listen-before-talk procedure initiated by the first terminal device; determining the timing for detecting the sidelink positioning reference signal if the second listen-before-talk procedure performed by the second terminal device is successful; and The second terminal device of claim 12, further storing instructions to cause the second terminal device to execute the following:

15. The one or more parameters associated with the first listen-before-talk procedure include: a start time or duration of the first listen-before-talk procedure; a back-off counter value for the first listen-before-talk procedure; a waiting period for the first listen-before-talk procedure; an energy threshold of the first listen-before-talk procedure, or a channel access priority class for the first listen-before-talk procedure; The second terminal device according to claim 14, comprising at least one of:

16. 13. The second terminal device of claim 12, wherein the first listen-before-talk procedure initiated by the first terminal device is a Type 1 listen-before-talk procedure, and the second listen-before-talk procedure performed in the second terminal device is a Type 1 listen-before-talk procedure.

17. 1. A method implemented in a first terminal device of a radio access network, comprising: initiating a first listen-before-talk procedure before transmitting a sidelink positioning reference signal to a second terminal device in the radio access network in an unlicensed spectrum during a sidelink positioning session; transmitting, in a permitted band, positioning-related control information to the second terminal device, the positioning-related control information including an instruction for the second terminal device to receive notification of whether the first listen-before-talk procedure initiated by the first terminal device is successful or to perform a second listen-before-talk procedure; transmitting the sidelink positioning reference signal in the unlicensed spectrum in response to successful completion of the first listen-before-talk procedure initiated by the first terminal device; A method comprising:

18. The method of claim 17 , wherein the positioning-related control information is transmitted before the first listen-before-talk procedure initiated by the first terminal device terminates.

19. transmitting, to the second terminal device, the notification of whether the first listen-before-talk procedure initiated by the first terminal device has been successful or not, on a sidelink feedback channel resource associated with the positioning-related control information, if the positioning-related control information includes the instruction for the second terminal device to receive the notification of whether the first listen-before-talk procedure initiated by the first terminal device has been successful or not; 20. The method of claim 17, further comprising:

20. 18. The method of claim 17, wherein the instructions for the second terminal device to perform the second listen-before-talk procedure include one or more parameters related to the first listen-before-talk procedure initiated by the first terminal device.

21. The one or more parameters associated with the first listen-before-talk procedure initiated by the first terminal device include: a start time or duration of the first listen-before-talk procedure; a back-off counter value for the first listen-before-talk procedure; a waiting period for the first listen-before-talk procedure; an energy threshold of the first listen-before-talk procedure, or a channel access priority class for the first listen-before-talk procedure; 21. The method of claim 20, comprising at least one of:

22. selecting a sidelink resource for transmitting the positioning-related control information to the second terminal device; and determining whether to notify the second terminal device whether the first listen-before-talk procedure initiated by the first terminal device has been successful or to instruct the second terminal device to perform the second listen-before-talk procedure based on at least one of a progress status of the first listen-before-talk procedure initiated by the first terminal device, a delay between the selected sidelink resource and a sidelink feedback channel resource associated with the selected sidelink resource, or a radio environment of the first terminal device and the second terminal device; 20. The method of claim 17, further comprising:

23. 23. The method of claim 22, wherein the first terminal device decides to notify the second terminal device whether the first listen-before-talk procedure initiated by the first terminal device has been successful if the delay between the selected sidelink resource and the sidelink feedback channel resource associated with the selected sidelink resource is longer than an estimated remaining time of the first listen-before-talk procedure initiated by the first terminal device.

24. 23. The method of claim 22, wherein the first terminal device determines to instruct the second terminal device to perform the second listen-before-talk procedure when the first terminal device and the second terminal device are in the same radio environment.

25. determining whether the first terminal device and the second terminal device are in the same radio environment before transmitting the positioning-related control information; 25. The method of claim 24, further comprising:

26. The first terminal device When the distance between the first terminal device and the second terminal device is equal to or less than a threshold value, or When the first terminal device and the second terminal device obtain the same measurement result by measuring the unlicensed band, 26. The method of claim 25, wherein the first terminal device and the second terminal device are determined to be in the same radio environment.

27. 18. The method of claim 17, wherein the first listen-before-talk procedure initiated by the first terminal device is a Type 1 listen-before-talk procedure, and the second listen-before-talk procedure performed at the second terminal device is a Type 1 listen-before-talk procedure.

28. 1. A method implemented in a second terminal device of a radio access network, comprising: receiving positioning-related control information via a sidelink in a licensed band from a first terminal device in the radio access network, the positioning-related control information including an instruction for the second terminal device to receive a notification of whether a first listen-before-talk procedure initiated by the first terminal device was successful or to perform a second listen-before-talk procedure; performing sidelink positioning reference signal detection in an unlicensed band at a timing determined based on the positioning-related control information; A method comprising:

29. receiving, on a sidelink feedback channel resource associated with the positioning-related control information, the indication of whether the first listen-before-talk procedure initiated by the first terminal device was successful, if the positioning-related control information includes the instruction for the second terminal device to receive the indication; and determining the timing for detecting sidelink positioning reference signals if the received notification indicates that the first listen-before-talk procedure initiated by the first terminal device is successful; and 30. The method of claim 28, further comprising:

30. receiving, when the positioning-related control information includes the instruction to cause the second terminal device to perform the second listen-before-talk procedure, performing the second listen-before-talk procedure, wherein the instruction to cause the second terminal device to perform the second listen-before-talk procedure includes one or more parameters related to the first listen-before-talk procedure initiated by the first terminal device; determining the timing for detecting the sidelink positioning reference signal if the second listen-before-talk procedure performed by the second terminal device is successful; and 30. The method of claim 28, further comprising:

31. The one or more parameters associated with the first listen-before-talk procedure include: a start time or duration of the first listen-before-talk procedure; a back-off counter value for the first listen-before-talk procedure; a waiting period for the first listen-before-talk procedure; an energy threshold of the first listen-before-talk procedure, or a channel access priority class for the first listen-before-talk procedure; 31. The method of claim 30, comprising at least one of:

32. 29. The method of claim 28, wherein the first listen-before-talk procedure initiated by the first terminal device is a Type 1 listen-before-talk procedure, and the second listen-before-talk procedure performed at the second terminal device is a Type 1 listen-before-talk procedure.

33. An apparatus implemented in a first terminal device of a radio access network, comprising: means for initiating a first listen-before-talk procedure prior to transmitting a sidelink positioning reference signal to a second terminal device in the radio access network in an unlicensed spectrum during a sidelink positioning session; means for transmitting positioning-related control information to the second terminal device in a permitted band, the positioning-related control information including an instruction for the second terminal device to receive notification of whether the first listen-before-talk procedure initiated by the first terminal device is successful or to perform a second listen-before-talk procedure; means for transmitting the sidelink positioning reference signal in the unlicensed spectrum in response to successful completion of the first listen-before-talk procedure initiated by the first terminal device; An apparatus comprising:

34. 34. Apparatus according to claim 33, further comprising means for carrying out the method according to any of claims 18 to 27.

35. An apparatus implemented in a second terminal device of a radio access network, comprising: means for receiving positioning-related control information via a sidelink in a licensed band from a first terminal device in the radio access network, the positioning-related control information including an instruction for the second terminal device to receive notification of whether a first listen-before-talk procedure initiated by the first terminal device has been successful or to perform a second listen-before-talk procedure; and means for performing sidelink positioning reference signal detection in an unlicensed band at a timing determined based on the positioning-related control information; An apparatus comprising:

36. 36. Apparatus according to claim 35, further comprising means for carrying out the method according to any of claims 29 to 32.

37. When executed by a first terminal device in a radio access network, the first terminal device is provided with at least: initiating a first listen-before-talk procedure before transmitting a sidelink positioning reference signal to a second terminal device in the radio access network in an unlicensed spectrum during a sidelink positioning session; transmitting, in a permitted band, positioning-related control information to the second terminal device, the positioning-related control information including an instruction for the second terminal device to receive notification of whether the first listen-before-talk procedure initiated by the first terminal device is successful or to perform a second listen-before-talk procedure; transmitting the sidelink positioning reference signal in the unlicensed spectrum in response to successful completion of the first listen-before-talk procedure initiated by the first terminal device; A computer-readable medium having stored thereon instructions for causing the computer to execute the method.

38. 38. The computer readable medium of claim 37, further comprising instructions stored thereon that, when executed by the first terminal device, cause the first terminal device to perform at least the method of any of claims 18 to 27.

39. When executed by a second terminal device in a radio access network, the second terminal device is provided with at least: receiving positioning-related control information via a sidelink in a licensed band from a first terminal device in the radio access network, the positioning-related control information including an instruction for the second terminal device to receive a notification of whether a first listen-before-talk procedure initiated by the first terminal device was successful or to perform a second listen-before-talk procedure; performing sidelink positioning reference signal detection in an unlicensed band at a timing determined based on the positioning-related control information; A computer-readable medium having stored thereon instructions for causing the computer to execute the method.

40. 40. The computer readable medium of claim 39, further comprising instructions stored thereon that, when executed by the second terminal device, cause the second terminal device to perform at least the method of any of claims 29 to 32.

Images