WO2022218515A1

WO2022218515A1 - User device and method for sidelink positioning

Info

Publication number: WO2022218515A1
Application number: PCT/EP2021/059605
Authority: WO
Inventors: Mario Hernán CASTAÑEDA GARCIA; Richard Stirling-Gallacher; Anastasios KAKKAVAS; Xitao Gong
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2022-10-20
Also published as: EP4309385A1; CN117063497A

Abstract

A user device is provided that is arranged to operate sidelink positioning, where the user device includes a transceiver configured to receive a first reference signal (RSI) at a receiving reference point and a processor configured to trigger a first time difference measurement report to be sent by the user device. The processor is further configured to cancel the triggered first time difference measurement report when the receiving reference point of the first reference signal (RSI) is different from a transmitting reference point of a second reference signal (RS2) and the user device is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting. Thus, an accurate time difference measurement of a user device is ensured for sidelink positioning by eliminating the TX/RX reference point uncertainty and avoiding unnecessary overhead and latency in the sidelink communication.

Description

USER DEVICE AND METHOD FOR SIDELINK POSITIONING

TECHNICAL FIELD

The present disclosure relates generally to the field of wireless positioning; and more specifically, to a user device to operate sidelink positioning and a method for the user device for sidelink positioning.

BACKGROUND

Sidelink communication, also known as direct device-to-device (D2D) communication, refers to the technology that allows user equipment (UEs) or user devices, such as cell phones or vehicles, to communicate with each other with or without the involvement of network infrastructures, such as an access point or base stations. The applications of sidelink communication may include, but is not limited to, emergency communications (e.g., ad hoc networks in case of natural disasters like hurricanes, earthquakes etc.), local services (e.g., proximity services like social media apps), and Intemet-of-Things (IoT) enhancement (e.g., vehicle-to-vehicle (V2V) or vehicle-to-everything (V2X) communication). Reference signals transmitted by UEs in the sidelink can be used for positioning, i.e. for sidelink positioning. Based on the reference signals, UEs can compute time difference measurements which can be used for sidelink positioning.

Typically, a time difference measurement between two nearby UEs (a reference UE and a target UE) in the sidelink (i.e., direct communication between two nearby UE) is used to compute a round trip time (RTT) by utilizing reference signals transmitted by the reference UE and reference signals transmitted by the target UE. The RTT can be computed at the network, at the location management function (LMF), at the reference UE, at the target UE or at another UE. If the RTT computation is done at the network, LMF or another UE, then the target UE and reference UE, each report their time difference to the network, LMF or the other UE. If the computation is done at the target UE or the reference UE, then one UE sends its time difference to the other UE (e.g., if the computation is done at the reference UE, the target UE reports its time difference to the reference UE). The RTT can further be used to calculate the positioning of the target UE or of the reference UE, i.e., relative position of one UE with respect to the other UE. The RTT provides the range information, i.e., ½ RTT provides an indication of the distance between the reference UE and the target UE. The RTT along with additional angular measurements can enable the positioning of the reference UE or the target UE.

Conventionally, a UE can be equipped with distributed antennas or multiple panels (i.e., a group of antennas). The panels used for transmission may or may not be the same as the panel used for reception, i.e., a UE with multiple panels can transmit a reference signal on one panel while it receives a reference signal on another panel. As the transmitting panel (TX panel), i.e., the panel used by the UE for the transmission of a reference signal may or may not be same as the receiving panel (RX panel), i.e., the panel used by the UE for the reception of a reference signal, it results in a TX/RX panel uncertainty for a conventional time difference measurement which may lead to an erroneous RTT computation. This can in turn result in an erroneous positioning of the UE. In addition, it may not be known whether a UE has multiple panels or not, which also increases the TX/RX panel uncertainty and can lead to erroneous positioning of the UEs.

To address the problem of TX/RX panel uncertainty, some conventional time difference measurement techniques use indexing panels based on prior measurements and transmissions of the UEs, with the aim of having the TX panel and the RX panel to be the same for a time difference measurement. However, it may not always be possible to have the TX panel and the RX panel to be the same. For example, a UE may autonomously turn off its panels (e.g., for power saving) after performing the prior measurements, the TX/RX panels that were not used before may now be available and/or the TX/RX panels that were used for previous measurements may no longer be available for the required measurement of a time difference. Moreover, in such conventional time difference measurement techniques, configuring a time difference measurement at each UE requires previous bi directional sidelink transmissions and measurements. However, the existence of prior measurements in one direction, does not imply the existence of prior measurements in the other direction, i.e., prior measurements may not be available. For example, a sidelink transmission from UE 1 to UE 2 for 5G new radio (NR) V2X, does not necessarily require a sidelink transmission from UE 2 to UE 1. Furthermore, as a UE may be moving and changing orientation (e.g., in V2X), a configuration based on prior measurements may be outdated. Thus, configuring a time difference measurement based on prior measurements does not necessarily avoid the problem of TX/RX panel uncertainty. In another scenario, some conventional time difference measurement techniques use a panel ID, i.e., an identifier of a panel among the panels of a UE. The panel ID can consist of the ID of the panel used for a measurement of a reference signal or the ID of the panel used for a transmission of a reference signal. The use of panel IDs requires additional signalling with indication of UE antenna/panel topology. However, the exchange of antenna topology and further information to support panel IDs among UEs add to unnecessary overhead and latency, which may not be desirable and not always be possible.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with TX/RX panel uncertainty in conventional time difference measurements of a user device for sidelink positioning.

SUMMARY

The present disclosure provides a user device to operate sidelink positioning and a method for user device arranged to operate sidelink positioning. The present disclosure provides a solution to the existing problem of TX/RX reference panel uncertainty in conventional time difference measurements of a user device for sidelink positioning. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art, and provide an improved method for time difference measurements of a user device for sidelink positioning and avoid unnecessary overhead and latency in the sidelink communication.

One or more objects of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

In one aspect, the present disclosure provides a user device arranged to operate sidelink positioning. The user device comprises of a transceiver and a processor. The transceiver is configured to receive a first reference signal (RSI) at a receiving reference point. The processor is configured to trigger a first time difference measurement report to be sent by the user device; cancel the triggered first time difference measurement report when the receiving reference point of the first reference signal (RSI) is different from the transmitting reference point of a second reference signal (RS2) and the user device is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting; and/or send the triggered first time difference measurement report. (Pre-)configuration refers to a configuration that is determined by another device, e.g., the network or another user device, and signalled to the user device; or to a predefined configuration in the user device.

The user device of the present disclosure enables to compute time difference measurements for sidelink positioning with high accuracy and reliability. The user device makes the sidelink positioning efficient and reliable, without introducing any noticeable latency or adding any unnecessary overhead. Moreover, the user device can be configured to send the first time difference measurement report only when the receiving reference point of the first reference signal (RSI) and transmitting reference point of the second reference signal (RS2) are the same. Therefore, the problem of TX/RX panel uncertainty in time difference measurements of the user device for sidelink positioning is overruled. Thus, the sidelink positioning (i.e., the position of the user device) can be determined accurately. As the TX panel and RX panel of a UE may not be the same, the receiving reference point and the transmitting reference point may not be the same. Thus, the TX/RX panel uncertainty represents a TX/RX reference point uncertainty, which is avoided in the present disclosure.

In an implementation form, the sending of the triggered first time difference measurement report comprises of sending a first time difference measurement report to indicate measurement result information or sending a first time difference measurement report to indicate a second time difference measurement is needed.

The sending of the triggered first time difference measurement report comprises of an indication. This indication may be that the measurement result information is obtained such that the transmitting and receiving reference point are the same. On the other hand, the indication may be that a second time difference measurement is needed, if the transmitting and receiving reference point are not the same. Therefore, the problem of TX/RX reference point uncertainty in time difference measurements of the user device for sidelink positioning is overruled. Thus, the sidelink positioning (i.e., the position of the user device) can be determined accurately.

In a further implementation form, the first time difference measurement report comprises of a first indicator which indicates whether the receiving reference point is the same as the transmitting reference point. Beneficially, by use of the first indicator, the TX/RX reference point uncertainty in time difference measurements of the user device for sidelink positioning is eliminated.

In a further implementation form, the processor is further configured to determine a first timing of the first reference signal; determine a second timing of the second reference signal; and determine a time difference between the first timing and the second timing.

The first timing of the first reference signal determines the time of reception of the first reference signal and the second timing of the second reference signal determines the time of transmission of the second reference signal. The difference of these two timings can be used to compute a time difference measurement. Time difference measurements at the user device and at another user device can be used to compute a round trip time (RTT) between the two user devices. The RTT can be used for sidelink positioning of the user device, i.e., relative positioning of one user device with respect to the other user device.

In a further implementation form, the transceiver is further configured to receive a third reference signal (RS3) at the transmitting reference point or transmit a fourth reference signal (RS4) from the receiving reference point.

By virtue of the third or fourth reference signals (RS3 or RS4), the user device can be (pre- )configured to receive the reference signal and transmit the reference signal from the same reference point, if they were initially not from the same reference point. This helps to eliminate the TX/RX reference point uncertainty in time difference measurements of the user device for sidelink positioning.

In a further implementation form, the indicated measurement result information comprises at least one of: relative displacement between the receiving reference point and the transmitting reference point; the orientation of the receiving and transmitting reference points.

By virtue of the indicated measurement result information, the RTT calculations can be computed with the help of the additional information, even if the receiving reference point of the first reference signal and the transmitting reference point of the second reference signal are not the same. This on-demand request for additional information, such as the relative displacement between the transmitting reference point and the receiving reference point; orientation of the transmitting reference point and the receiving reference point; the user device’s panel capabilities (e.g., whether the transmitting reference point and the receiving reference point are fully symmetric, or not), panel ID, type of panel (e.g., bumper, rool), etc., enables the RTT calculation, without introducing any noticeable latency or adding any unnecessary overhead.

In a further implementation form, the first and second reference points are the same if they are within a threshold distance from one another.

If the two reference points are placed close to each other such that they are within a threshold distance from one another, then both the reference points can be treated as the same reference point. Hence, the RTT can be computed based on these reference points.

In another aspect, the present disclosure provides a method for a user device arranged to operate sidelink positioning. The method comprises: receiving a first reference signal (RSI) at a receiving reference point; triggering a first time difference measurement report to be sent by the user device; cancelling the triggered first time difference measurement report when the receiving reference point of the first reference signal (RSI) is different from the transmitting reference point of the second reference signal (RS2) and the user device is (pre- )configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting; and/or sending the triggered first time difference measurement report.

The method provides an efficient and reliable sidelink positioning solution for the user device without introducing any noticeable latency or adding any unnecessary overhead. Moreover, the method enables sending the first time difference measurement report only when the receiving reference point of the first reference signal (RSI) and transmitting reference point of the second reference signal (RS2) are the same. Therefore, the problem of TX/RX reference point uncertainty in time difference measurements of the user device for sidelink positioning is overruled. Thus, the sidelink positioning (i.e., the position of the user device) can be determined accurately. Further, the method executed by the user device achieves all the advantages and effects of the user device of the present disclosure.

In yet another aspect, the present disclosure provides a computer-readable medium carrying computer instructions that when loaded into and executed by a processor of a user device enables the user device to implement the method of aforementioned aspect. The computer-readable media product achieves all the advantages and effects of the respective method of the present disclosure.

It has to be noted that all devices, elements, circuitry, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1A is a block diagram of a user device arranged to operate sidelink positioning, in accordance with an embodiment of the present disclosure; FIG. IB is a block diagram that illustrates various exemplary components of a user device, in accordance with an embodiment of the present disclosure;

FIG. 2 is a flowchart for a method for a user device arranged to operate sidelink positioning, in accordance with an embodiment of the present disclosure;

FIG. 3 is a flowchart of a process for implicit indication, in accordance with an embodiment of the present disclosure;

FIG. 4 is a flowchart of a process for explicit indication, in accordance with an embodiment of the present disclosure;

FIG. 5 is an exemplary illustration of a first scenario for sidelink positioning, in accordance with another embodiment of the present disclosure;

FIG. 6 is an exemplary illustration of a second scenario for sidelink positioning, in accordance with another embodiment of the present disclosure;

FIG. 7 is an exemplary illustration of a third scenario for sidelink positioning, in accordance with another embodiment of the present disclosure;

FIG. 8 is an exemplary illustration of a fourth scenario for sidelink positioning, in accordance with another embodiment of the present disclosure;

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non- underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible. FIG. 1A is a block diagram of a user device arranged to operate sidelink positioning, in accordance with an embodiment of the present disclosure. With reference to FIG. 1A, there is shown a block diagram 100 that includes a first user device (hereinafter simply referred to as a user device 102) and a second user device 104. In an implementation, the user device 102 includes one or more transmitting or receiving reference points, such as TX/RX reference points 106A-106N. Similarly, the second user device 104 includes one or more TX/RX reference points 108A-108N. A TX/RX reference point may be associated with a TX/RX panel. There is further shown a first reference signal (RSI) 110 and a second reference signal 112 (RS2).

The user device 102 includes suitable logic, circuitry, and/or interfaces that is configured to establish sidelink transmission of reference signals with other user devices, such as the second user device 104, by transmitting and receiving reference signals at the one or more transmitting or receiving reference points, such as TX/RX reference points 106A-106N. The information obtained from the transmitted and received reference signals of the user device 102 can be used to compute a time difference measurement report. The time difference measurements can further be used to compute a round trip time (RTT), which can be used for sidelink positioning of the user device 102 or any other user device. Examples of the user device 102 include, but is not limited to a vehicle (e.g., car), a smart phone, a laptop computer, an Intemet-of-Things (IoT) device, a machine type communication (MTC) device, an evolved universal mobile telecommunications system (UMTS) terrestrial radio access (E-UTRAN), NR-dual connectivity (EN-DC) device, a drone, a customized hardware for wireless telecommunication, or any other portable or non-portable electronic device.

The user device 102 may be equipped with distributed antennas or multiple panels. The panel may be represented as group of antennas, an antenna array, or an antenna subarray. The panel may be controlled by one or more oscillators. Further, one antenna panel may be driven by one RF chain, or may be driven by multiple RF chains. The RF chain may be referred to as a receive chain and/or a transmit chain, a receiver branch and/or a transmitter branch, or the like. The panel is a set of ports with independent RF chains. One panel may have one or more RF chains, and one RF chain may correspond to one independent beam. The panel can also be defined as an entity associated with one or more reference points, such as TX/RX reference points 106A-106N. Each reference point, such as TX/RX reference points 106A- 106N, can be used to transmit or receive reference signals (e.g., first reference signal (RSI) 110 and second reference signal 112 (RS2). A receiving reference point can be a transmitting reference point and the transmitting reference point can be a receiving reference point. The receiving reference point, i.e., each of the one or more TX/RX reference points 106A-106N, can be a receiving antenna connector of the user device 102. The receiving reference point, i.e., each of the one or more TX/RX reference points 106A-106N, can be the centre location of the radiating region of a receiving antenna. The transmitting reference point, i.e., each of the one or more TX/RX reference points 106A-106N, can be a transmitting antenna connector of the user device 102. The transmitting reference point, i.e., each of the one or more TX/RX reference points 106A-106N, can be the centre location of the radiating region of a transmitting antenna.

The second user device 104 includes suitable logic, circuitry, and/or interfaces that is configured to establish sidelink transmission of reference signals with other user devices, such as the user device 102, by transmitting and receiving reference signals at the one or more transmitting or receiving reference points, such as TX/RX reference points 108A- 108N. The information obtained from the transmitted and received reference signals of the second user device 104 can be used to compute a time difference measurement report. The time difference measurements can further be used to compute a round trip time (RTT), which can be used for sidelink positioning of the second user device 104 or any other user device. Examples of the second user device 104 include, but is not limited to a vehicle (e.g., car), a smart phone, a laptop computer, an Intemet-of-Things (IoT) device, a machine type communication (MTC) device, an evolved universal mobile telecommunications system (UMTS) terrestrial radio access (E-UTRAN), NR-dual connectivity (EN-DC) device, a drone, a customized hardware for wireless telecommunication, or any other portable or non portable electronic device.

Like the user device 102, the second user device 104 may be equipped with distributed antennas or multiple panels. The panel may be represented as group of antennas, an antenna array, or an antenna subarray. The panel can also be defined as an entity associated with one or more reference points, such as TX/RX reference points 108A-108N. Each reference point, such as TX/RX reference points 108A-108N, can be used to transmit or receive reference signals (e.g., first reference signal 110 (RSI) and second reference signal 112 (RS2).

The first reference signal 110 (RSI) refers to the signal received by the user device 102 from another user device, such as the second user device 104, at the receiving reference point, such as the TX/RX reference point 106B, of the user device 102. The second reference signal 112 (RS2) refers to the signal transmitted by the user device 102 to another user device, such as the second user device 104, from the transmitting reference point, such as the TX/RX reference point 106A, of the user device 102. The RSI 110 and RS2 112 are used for the computation of the RTT to operate sidelink positioning of the user device 102 and/or the second user device 104.

In one aspect, the present disclosure provides a user device 102, arranged to operate sidelink positioning, the user device 102 comprising a transceiver being configured to receive a first reference signal 110 (RSI), at a receiving reference point and a processor being configured to trigger a first time difference measurement report to be sent by the user device 102, and a) cancel the triggered first time difference measurement report when the receiving reference point of a first reference signal 110 (RSI), is different from a transmitting reference point of a second reference signal 112 (RS2), and the user device 102 is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting, and/or, b) send the triggered first time difference measurement report.

In operation, the user device 102 receives the first reference signal 110 (RSI) from another user device, such as the second user device 104, at the receiving reference point, such as one of the TX/RX reference points 106A-106N, and transmits the second reference signal 112 (RS2) to another user device, such as the second user device 104, from the transmitting reference point, such as one of the TX/RX reference points 106A-106N.

The user device 102 triggers a first time difference measurement report to be sent by the user device 102. The first time difference measurement report (associated with the distance between the user device 102 and any other user device, such as the second user device 104) is triggered based on the reception of the first reference signal 110 (RSI) and the transmission of the second reference signal 112 (RS2). The first time difference measurement can be configured by the network, by the location management function

(LMF), by the user device 102, by the second user device 104, or by any other user device. For example, consider the user device 102 as the reference UE and the second user device 104 as the target UE or target device. Let t₀ be the time at the TX/RX reference point 106A when the user device 102 transmits the second reference signal 112 (RS2), t be the time at the TX/RX reference point 108B when the second user device 104 receives the second reference signal 112 (RS2) from the user device 102, t₂ be the time at the TX/RX reference point 108A when the second user device 104 transmits the first reference signal 110 (RSI), and t₃ be the time at the TX/RX reference point 106B when the user device 102 receives the first reference signal 110 (RSI). With these timings, the first time difference measurement report at the reference UE, i.e., the user device 102, and at the target UE, i.e., the second user device 104, is determined as the time difference derived at the user device 102 equal to t₃ — t₀, and the time difference derived at the second user device 104 equal to t — t₂. When reporting the first time difference measurement, the reporting user device indicates whether the receiving reference point, such as one of the TX/RX reference points 106A-106N, used for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, used for the second reference signal 112 (RS2) are the same or not. Such indication can be performed implicitly or explicitly as described further in the FIG. 2 and FIG. 3, respectively. The reporting user device can be the user device 102 and/or any other user device, such as the second user device 104. The advantage of this indication is that it enables the computation of the RTT, taking into account whether for the triggered first time difference measurement the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same or not. For example, based on the first time difference measurement report, the RTT between the user device 102 and the second user device 104 can be computed by taking the sum of the two time differences as represented by the equation 1.

RTT = (t₃ — t₀) + (U — t₂) (1)

If the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same for the triggered first time difference measurement report of the reference UE, i.e., the user device 102, then there is one reference point at the user device 102. Thus, the range information between the reference UE, i.e., the user device 102, and the target UE, i.e., the second user device 104, corresponds to a fixed distance, i.e., the possible locations of the second user device 104 with respect to the user device 102, lies on a circle of radius ½ RTT and with the user device 102 at the centre. However, the user device 102 may have multiple reference points, i.e., the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, may not be the same. In this case, in conventional systems and methods, the range information provided by the RTT is no longer described by a circle and can lead to unknown erroneous positioning of the target UE.

In contradiction to the conventional systems, in the present disclosure, the user device 102 cancels the triggered first time difference measurement report, if for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different. Cancelling the triggered first time difference measurement report indicates to the target device, e.g., the second user device 104 computing the RTT, that for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different. If the user device 102, indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are different for the first set of reference signals (i.e., RSI 110 and RS2112), then a second set of reference signals at the user device 102, can be configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same for the second time difference measurement report. This configuration has the advantage that it is based on recent set of reference signals measurements and no prior measurements are required to compute the RTT. In addition, performing this further optional configuration on demand has the advantage that it is only performed if needed and hence, avoids unnecessary overhead and latency.

The user device 102 further sends the triggered first time difference measurement report, if for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same. If the user device 102, indicates that the receiving reference point, such as one of the TX/RX reference points 106A- 106N, and the transmitting reference point, such as one of the TX/RX reference points 106A- 106N, are the same for the given set of reference signals (e.g., RSI 110 and RS2 112), then the sent time difference measurement report can be used to compute the RTT. Since there is no uncertainty about the TX/RX reference point, the RTT computation is performed knowing that for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same. In this case, for example, the RTT can be computed, e.g., based on equation 1. Thus, accurate results may be obtained for the sidelink positioning of the user device 102. The problem of uncertainty about the TX/RX reference point can be solved either by implicit or explicit indication, which is further described in the FIGs, IB, 2 and 3.

FIG. IB is a block diagram that illustrates various exemplary components of a user device, in accordance with an embodiment of the present disclosure. With reference to FIG. IB, there is shown the user device 102. In an implementation, the user device 102 includes a transceiver 114, a processor 116 and a memory 118.

The transceiver 114 of the user device 102, includes suitable logic, circuitry, and/or interfaces that is configured to transmit or receive the reference signals (e.g., RSI 110 and RS2 112). Examples of the transceiver 114 include, but is not limited to a transmitter/receiver antenna, an Intemet-of-Things (IoT) controller, a network interface, a customized hardware for wireless telecommunication, or the like.

The processor 116 of the user device 102, includes a suitable logic circuitry that may be configured to monitor and execute operations of the user device 102. Examples of the processor 116 include, but is not limited to, a microprocessor, a microcontroller, a complex instruction set computing (CISC) processor, an application-specific integrated circuit (ASIC) processor, a reduced instruction set (RISC) processor, a very long instruction word (VLIW) processor, a central processing unit (CPU), a state machine, a data processing unit, and other processors or control circuitry.

The memory 118 of the user device 102, includes a suitable logic, circuitry, and/or interfaces that may be configured to temporally store reference signals transmitted or received by the user device 102. Examples of implementation of the memory 118 may include, but are not limited to, Random Access Memory (RAM), Hard Disk Drive (HDD), Flash memory, Solid- State Drive (SSD), and/or CPU cache memory.

In operation, the transceiver is configured to receive a first reference signal 110 at a receiving reference point. The transceiver 114 of the user device 102 receives the first reference signal 110 (RSI) from another user device, such as the second user device 104, at the receiving reference point, such as one of the TX/RX reference points 106A-106N, and transmits the second reference signal 112 (RS2) to another user device, such as the second user device 104, from the transmitting reference point, such as one of the TX/RX reference points 106A- 106N

The processor 116 is configured to trigger a first time difference measurement report to be sent by the user device 102. The processor 116 is further configured to: a) cancel the triggered first time difference measurement report when the receiving reference point of the first reference signal 110 (RSI), is different from a transmitting reference point of a second reference signal, RS2 (112), and when the user device 102 is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting and/or, b) send the triggered first time difference measurement report. Alternatively stated, the processor 116 of the user device 102 triggers a first time difference measurement report to be sent by the user device 102. Further, the processor 116 of the user device 102 cancels the triggered first time difference measurement report, if for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different. The term "(Pre- configuration" refers to a configuration that is determined by another device, e.g., the network or another user device, such as the second user device 104, and signalled to the user device 102; or to a predefined configuration in the user device.

Iln accordance with an embodiment, the transceiver 114 is further configured to transmit the second reference signal 112 (RS2) to the second user device 104. The processor 116 of the user device 102 process these reference signals, i.e., RSI 110 and RS2 112, and triggers the first time difference measurement report to be sent by the user device 102, which helps to operate the sidelink positioning (i.e., the position of the user device 102 and/or the second user device 104). In an implementation, for example, in a process for implicit indication, the processor 116 of the user device 102 sends the triggered first time difference measurement report if the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same, else the first time difference measurement report is cancelled. In another implementation, for example, in a process of explicit indication, the processor 116 of the user device 102 always sends the triggered first time difference measurement report. The process of implicit indication is described in detail, for example, in FIG. 3. The process of explicit indication is described in details, for example, in FIG. 4.

In accordance with an embodiment, sending the triggered first time difference measurement report comprises of sending a first time difference measurement report to indicate measurement result information or sending a first time difference measurement report to indicate a second time difference measurement is needed. The sending of the triggered first time difference measurement report comprises of an indication. The indication may be a piece of information or a notification that informs the target device receiving the time difference measurement report, e.g., the target UE which computes the RTT. This indication may be that the measurement result information is obtained such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same. The measurement result comprises of the time difference between the time of reception of the first reference signal 110 and the time of transmission of the second reference signal 112. On the other hand, the indication may be that a second time difference measurement is needed, if the transmitting reference point, such as one of the TX/RX reference points 106A- 106N, and receiving reference point, such as one of the TX/RX reference points 106A-106N, are not the same. Therefore, the problem of TX/RX reference point uncertainty in time difference measurements of the user device for sidelink positioning is overruled. Thus, the sidelink positioning (i.e., the position of the user device 102 and the second user device 104) can be determined accurately.

In accordance with an embodiment, the first time difference measurement report comprises of a first indicator which indicates whether the receiving reference point is the same as the transmitting reference point. The first time difference measurement report comprises of a one-bit indicator, which can indicate two states. The first state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. On the other hand, the second state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is not the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. Beneficially, the TX/RX reference point uncertainty in time difference measurements of the user device 102 for sidelink positioning is eliminated. The user device 102 can send the first indicator along with the first time difference measurement.

In accordance with an embodiment, the processor 116 is further configured to determine a first timing of the first reference signal 110 (RSI); determine a second timing of the second reference signal 112 (RS2); and determine a time difference between the first timing and the second timing. The first timing of the first reference signal 110 (RSI) determines the time of reception of the first reference signal 110 (RSI) at the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the user device 102. The second timing of the second reference signal 112 (RS2) determines the time of transmission of the second reference signal 112 (RS2) at the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the user device 102. The difference of these two timings, i.e., the first timing and the second timing, can be used to compute a round trip time (RTT). For example, consider the user device 102 as the reference UE and the second user device 104 as the target UE. Let t₀ be the time when the user device 102 transmits the second reference signal 112 (RS2), t be the time when the second user device 104 receives the second reference signal 112 (RS2) from the user device 102, t₂ be the time when the second user device 104 transmits the first reference signal 110 (RSI), and t₃ be the time when the user device 102 receives the first reference signal 110 (RSI). With these timings, the first time difference measurement report at the user device 102, and at the second user device 104, is determined as the time difference derived at the user device 102 equals to t₃ — t₀, and the time difference derived at the second user device 104 equals to t_t — t₂. Based on the first time difference measurement report, the RTT between the user device 102 and the second user device 104 can be computed by taking the sum of the two time differences as represented by the equation 1 (given in FIG. 1A). The RTT provides the range information, i.e., ½ RTT provides an indication of the distance between the two user devices, such as the user device 102 and the second user device 104. Thus, the RTT information along with additional angular measurements can enable the positioning of the user device 102 and/or the second user device 104, i.e., relative positioning of one user device with respect to the other user device.

In accordance with an embodiment, the transceiver 114 is further configured to receive a third reference signal (RS3) at the transmitting reference point or transmit a fourth reference signal (RS4) from the receiving reference point. The user device 102, can cancel the triggered first time difference measurement report, if the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2) and the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RSI) 110 are different. The user device 102, can indicate with the first indicator that the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RSI) 110 and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2) are different. Under such situations, a second set of reference signals (i.e., RS3 and RS4) at the user device 102, can be configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RS4) and the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RS3) are the same. This configuration has the advantage that it is based on recent set of reference signals measurements and no prior measurements are required to compute the RTT.

In accordance with an embodiment, the indicated measurement result information comprises at least one of: relative displacement between the receiving reference point and the transmitting reference; the orientation of the receiving and transmitting reference points. If the user device 102 indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RSI) 110 and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2) are different, then the user device 102 may be configured to provide further information related to the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and receiving reference point, such as one of the TX/RX reference points 106A-106N, associated with the first time difference measurement. This information may include, but is not limited to relative displacement between the transmitting reference point (such as one of the TX/RX reference points 106A-106N) and the receiving reference point (such as one of the TX/RX reference points 106A-106N); orientation of the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N; the user device’s panel capabilities (e.g., whether the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are fully symmetric, or not), panel ID, type of panel (e.g., bumper, rool), etc. The panel-related information can be used to compute the RTT, along with the associated first time difference measurement report. This optional configuration can be performed on demand, i.e., in case the user device 102 continuously reports that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different for several time difference measurements, despite being configured to transmit the reference signal from the reference point used to receive a given reference signal (or to receive the reference signal at the reference point used to transmit a given reference signal). Such a situation can happen if the user device 102 has only one transmitting reference point, such as one of the TX/RX reference points 106A- 106N, and one receiving reference point, such as one of the TX/RX reference points 106A- 106N, which are not fully symmetric. Thus, performing the further optional configuration on demand has the advantage that it is only performed if needed and hence, avoids unnecessary overhead and latency.

In accordance with an embodiment, the first and second reference points are the same if they are within a threshold distance from one another. The threshold distance can be (pre- )configured at the user device 102 or at the second user device 104. The threshold distance can also be received by the user device 102 from the network, the LMF, or another user device, such as the second user device 104. If the two reference points (e.g., the transmitting reference point, and the receiving reference point) are placed close to each other such that they are within a threshold distance from one another, then both the reference points can be treated as the same reference point. Hence, the RTT computation from these reference points can be considered to be free of any TX/RX reference point uncertainty and the sidelink positioning of the user device 102 and/or the second user device 104, can be operated accurately. FIG. 2 is a flowchart for a method for a user device arranged to operate sidelink positioning, in accordance with an embodiment of the present disclosure. With reference to FIG. 2, there is shown a method 200. FIG. 2 is described in conjunction with elements of FIG. 1 A and IB. The method 200 is for a user device 102 arranged to operate sidelink positioning described, for example, in FIG. 1A and FIG. IB. The method 200 includes steps 202 to 208.

In yet another aspect, the present disclosure provides a method 200 for a user device 102 arranged to operate sidelink positioning, wherein the method 200 comprises: receiving a first reference signal 110 (RSI) at a receiving reference point; triggering a first time difference measurement report to be sent by the user device 102, and a) cancelling the triggered first time difference measurement report when the receiving reference point of the first reference signal 110 (RSI), is different from a transmitting reference point of a second reference signal 112 (RS2) and the user device 102 is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting, and/or, b) sending the triggered first time difference measurement report.

At step 202, the method 200 comprises receiving a first reference signal 110 (RSI) at a receiving reference point, such as one of the TX/RX reference points 106A-106N. The user device 102 receives the first reference signal 110 (RSI) from another user device, such as the second user device 104, at the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the user device 102.

At step 204, the method 200 further comprises triggering a first time difference measurement report to be sent by the user device 102. The first time difference measurement report

(associated with the distance between the user device 102 and any other user device, such as the second user device 104) is triggered based on the reception of the first reference signal

110 (RSI) and the transmission of the second reference signal 112 (RS2). The first time difference measurement can be configured by the network, by the location management function (LMF), by the user device 102, by the second user device 104, or by any other user device. For example, consider the user device 102 as the reference UE and the second user device 104 as the target UE. Let t₀ be the time when the user device 102 transmits the second reference signal 112, U be the time when the second user device 104 receives the second reference signal 112 from the user device 102, t₂ be the time when the second user device 104 transmits the first reference signal 110, and t₃ be the time when the user device 102 receives the first reference signal 110. With these timings, the first time difference measurement report at the user device 102 and at the second user device 104, is determined as the time difference derived at the user device 102 equals to t₃ — t₀ and the time difference derived at the second user device 104 equals to

— 1₂. When reporting the first time difference measurement, the reporting user device indicates whether the receiving reference point, such as one of the TX/RX reference points 106A-106N, used for the first reference signal 110 and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, used for the second reference signal 112 are same or not. The reporting user device can be the user device 102 and/or any other user device, such as the second user device 104.

In accordance with an embodiment, the first time difference measurement report comprises of a first indicator which indicates whether the receiving reference point is the same as the transmitting reference point. The first time difference measurement report comprises of a one-bit indicator, which can indicate two states. The first state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. On the other hand, the second state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is not the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. The first indicator can be sent along with the first time difference measurement.

In accordance with an embodiment, the method 200 further comprises transmitting the second reference signal 112 (RS2) to the second user device 104. The transceiver 114 is further configured to transmit the second reference signal 112 (RS2) to the second user device 104. By virtue of the second reference signal 112 (RS2), the user device 102 can establish sidelink communication with another user device, such as the second user device 104. The second reference signal 112 (RS2) along with first reference signal 110 (RSI) helps to trigger the first time difference measurement report, which is required for the RTT computation for sidelink positioning of the user device 102 and/or any other user device, such as the second user device 104. In accordance with an embodiment, the method 200 further comprises determining a first timing of the first reference signal 110 (RSI); determining a second timing of the second reference signal 112 (RS2); and determine a time difference between the first timing and the second timing. This difference between the first timing and the second timing is used to trigger the first time difference measurement report for the computation of RTT to operate sidelink positioning of the user device 102 and/or any other user device, such as the second user device 104.

At step 206, the method 200 further comprises cancelling the triggered first time difference measurement report when the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the first reference signal 110 (RSI), is different from the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2). If the user device 102, indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are different for the first set of reference signals (i.e., RSI 110 and RS2 112), then a second set of reference signals at the user device 102, can be configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same for the second time difference measurement report.

In accordance with an embodiment, the method 200 further comprises receiving a third reference signal (RS3) at the transmitting reference point or transmit a fourth reference signal (RS4) from the receiving reference point. When the user device 102 indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RSI) 110 and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2) are different, a second set of reference signals (i.e., RS3 and RS4) can be configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RS4) and the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RS3) are the same.

In accordance with an embodiment, the indicated measurement result information comprises at least one of: displacement between the receiving reference point and the transmitting reference; the orientation of the receiving and transmitting reference points. When the user device 102 continuously reports that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different for several time difference measurements, the user device 102 may be configured to provideadditional panel related information to compute the RTT.

At step 208, the method 200 further comprises sending the triggered first time difference measurement report. The user device 102 sends the triggered first time difference measurement report if for the triggered first time difference measurement report, the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same. If the user device 102, indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same for the given set of reference signals (e.g., RSI 110 and RS2 112), then the sent time difference measurement report can be used to compute the RTT. For example, based on the first time difference measurement report, the RTT between the user device 102 and the second user device 104 can be computed by taking the sum of the two time differences as represented by the equation 1 (given in FIG. 1 A). The user device 102 can also send the triggered first time difference measurement report along with the first indicator.

In accordance with an embodiment, sending the triggered first time difference measurement report comprises of sending a first time difference measurement report to indicate measurement result information or sending a first time difference measurement report to indicate a second time difference measurement is needed. The sending of the triggered first time difference measurement report comprises of an indication. This indication may be that the measurement result information is obtained such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and receiving reference point, such as one of the TX/RX reference points 106A-106N, are the same. On the other hand, the indication may be that a second time difference measurement is needed, if the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and receiving reference point, such as one of the TX/RX reference points 106A-106N, are not the same. The steps 202 to 208 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

The method 200 provide an efficient and reliable sidelink positioning solution for the user device 102 without introducing any noticeable latency or adding any unnecessary overhead. Moreover, the method 200 enables sending the first time difference measurement report only when the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the first reference signal 110 (RSI) and transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the second reference signal 112 (RS2) are the same. Therefore, the problem of TX/RX reference point uncertainty in time difference measurements of the user device 102 for sidelink positioning is overruled. Thus, the sidelink positioning (i.e., the position of the user device 102) can be determined accurately.

In yet another aspect, the present disclosure provides a computer-readable medium carrying computer instructions that when loaded into and executed by a processor 116 of a user device 102 enables the user device 102 to implement the method 200. The computer-readable medium refers to a non-transitory computer-readable storage medium. Examples of implementation of the computer-readable medium include, but is not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Random Access Memory (RAM), Read Only Memory (ROM), Hard Disk Drive (HDD), Flash memory, a Secure Digital (SD) card, Solid-State Drive (SSD), a computer readable storage medium, and/or CPU cache memory.

FIG. 3 is a flowchart of a process for implicit indication, in accordance with an embodiment of the present disclosure. FIG. 3 is described in conjunction with elements of FIG. 1A and IB. With reference to FIG. 3, there is shown a process of implicit indication 300, where a reporting UE implicitly indicates whether a receiving reference point (e.g., Rx panel) used for a first RS reception and the transmitting reference point (e.g., Tx panel) used for a first RS transmission are the same or not. In the process of implicit indication 300, a UE either reports or does not report a first time difference measurement depending on whether the transmitting reference point is same as the receiving reference point. The process of implicit indication 300 includes operations 302 to 308. At operation 302, a first time difference measurement report is triggered at a reporting UE, such as the user device 102. The first time difference measurement report is triggered based on the reception of the first reference signal 110 (RSI) at the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmission of the second reference signal 112 (RS2) from the transmitting reference point, such as one of the TX/RX reference points 106A-106N.

In accordance with an embodiment, the processor 116 is further configured to determine a first timing of the first reference signal 110 (RSI); determine a second timing of the second reference signal 112 (RS2); and determine a time difference between the first timing and the second timing. This difference between the first timing and the second timing is used to compute the first time difference measurement report of the user device 102.

At operation 304, it is determined whether the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, used for the computation of the first time difference measurement report are the same or not. In a case where the receiving reference point is same as the transmitting reference point, the control moves to operation 306 else if not same, the control moves to operation 310. In accordance with an embodiment, the first time difference measurement report comprises of a first indicator which indicates whether the receiving reference point is the same as the transmitting reference point. The sending of the first time-difference measurement report comprises of an indicator, which indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is the same as the transmitting reference point, such as one of the TX/RX reference points 106A- 106N. On the other hand, the cancelling of the first time-difference measurement report indicates that the receiving reference point, such as one of the TX/RX reference points 106A- 106N, is not the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N

At operation 306, the triggered first time difference measurement report is sent by the user device 102 to the target UE, such as the second user device 104. The user device 102 reports the triggered first time difference measurement report only if the receiving reference point, such as one of the TX/RX reference points 106A-106N, for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-

106N, for the second reference signal 112 (RS2) are the same reference points. At operation 308, the RTT is computed based on the triggered first time difference report. Since the user device 102 sends the triggered first time difference measurement report only if the receiving reference point, such as one of the TX/RX reference points 106A-106N, for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, for the second reference signal 112 (RS2) are the same reference points, the RTT is computed by the user device 102 knowing the fact that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points.

At operation 310, the triggered first time difference measurement report is cancelled by the user device 102. The user device 102 cancels the triggered first time difference measurement report if the receiving reference point, such as one of the TX/RX reference points 106A- 106N, for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, for the second reference signal 112 (RS2) are not the same reference points.

At operation 312, the user device 102 is configured such that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points for a second time difference measurement report.

In accordance with an embodiment, a third reference signal (RS3) is received at the transmitting reference point by the user device 102 or a fourth reference signal (RS4) is transmitted from the receiving reference point by the user device 102. When the user device 102 cancels the triggered first time difference measurement report, a second set of reference signals (i.e., RS3 and RS4) is configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A- 106N, of the reference signal (RS4) and the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the reference signal (RS3) are the same.

The operations 302 to 312 are only illustrative and other alternatives can also be provided where one or more operations are added, one or more operations are removed, or one or more operations are provided in a different sequence without departing from the scope of the claims herein. In the process of implicit indication 300, the user device 102 is configured to report the first time difference measurement and compute the RTT only after knowing that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points for the reported first time difference measurement report. If the user device does not report the triggered first time difference measurement report, the user device 102 can then be configured further such that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same for the second time difference measurement report.

FIG. 4 is a flowchart of a process for explicit indication, in accordance with an embodiment of the present disclosure. FIG. 4 is described in conjunction with elements of FIG. 1A and IB. With reference to FIG. 4, there is shown a process of explicit indication 400, where a reporting UE explicitly indicates whether a receiving reference point (e.g., Rx panel) used for a first RS reception and the transmitting reference point (e.g., Tx panel) used for a first RS transmission are the same or not. In the process of explicit indication 400, a UE is either configured to send a second time difference measurement report or to provide additional information related to the Tx panel and the Rx panel of the first reported time difference measurement on demand. The process of explicit indication 400 includes operations 402 to 412

At operation 402, a first time difference measurement report is triggered at a reporting UE, such as the user device 102. The first time difference measurement report is triggered based on the reception of the first reference signal 110 (RSI) at the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmission of the second reference signal 112 (RS2) at the transmitting reference point, such as one of the TX/RX reference points 106A-106N.

In accordance with an embodiment, the processor 116 is further configured to determine a first timing of the first reference signal 110 (RSI); determine a second timing of the second reference signal 112 (RS2); and determine a time difference between the first timing and the second timing. This difference between the first timing and the second timing is used to compute the first time difference measurement report of the user device 102. At operation 404, the triggered first time difference measurement and the first indicator are sent by the user device 102 to the target device, such as the second user device 104. For operation 406, the user device 102 determines whether the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, used for the computation of the first time difference measurement report are the same or not. In accordance with an embodiment, the first time difference measurement report comprises of a first indicator which indicates whether the receiving reference point is the same as the transmitting reference point. The first time difference measurement report comprises of a one-bit indicator, which can indicate two states. The first state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. On the other hand, the second state indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, is not the same as the transmitting reference point, such as one of the TX/RX reference points 106A-106N. After the triggered first time difference measurement and the first indicator are received by the target device, there are two cases depending on the first indicator. In a case where the receiving reference point is same as the transmitting reference point, the control moves to operation 408 else if not same, there are two options, and the control moves to operation 410 or 412.

At operation 408, the RTT is computed at the target device based on the triggered first time difference measurement report. In case the first indicator indicates that for the triggered first time difference measurement the receiving reference point, such as one of the TX/RX reference points 106A-106N, for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, for the second reference signal 112 (RS2) are the same reference points, the RTT is computed by the user device 102 knowing the fact that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points.

At operation 410, configuring of the user device 102 is carried out (when the transmitting reference point is not same as the receiving reference point) such that transmitting reference point can be the same as the receiving reference point. It includes operations 410A to 410D. At operation 410A, the user device 102 is configured if the receiving reference point, such as one of the TX/RX reference points 106A-106N, for the first reference signal 110 (RSI) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, for the second reference signal 112 (RS2) are not the same reference points. The user device 102 is configured such that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points for a second time difference measurement report.

At operation 410B, the second time difference measurement is measured by the user device 102 such that the receiving reference point, such as one of the TX/RX reference points 106A- 106N, of a third reference signal (RS3) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of a fourth reference signal (RS4) are the same reference points. In accordance with an embodiment, the transceiver 114 is further configured to receive a third reference signal (RS3) at the transmitting reference point or transmit a fourth reference signal (RS4) from the receiving reference point. When the user device 102 has indicated that for the triggered first time-difference measurement report the receiving reference point and the transmitting reference point are different, a second set of reference signals (i.e., RS3 and RS4) is configured for a second time difference measurement report such that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, of the fourth reference signal (RS4) and the receiving reference point, such as one of the TX/RX reference points 106A-106N, of the third reference signal (RS3) are the same.

At operation 410C, the second time difference measurement report is sent by the user device 102 to the target device, i.e., the second user device 104. The second time difference measurement report can include the first indicator for the second time difference measurement.

At operation 410D, the RTT is computed at the target device based on the second time difference report. If the receiving reference point, such as one of the TX/RX reference points

106A-106N, for the third reference signal (RS3) and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, for the fourth reference signal (RS4) are the same reference points, the RTT is computed by the target device knowing the fact that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same reference points.

At operation 412, additional information is requested related to the panels (Tx panel and Rx panel, i.e., transmitting reference point and the receiving reference point). The operation 412 includes certain sub-steps, such as operations 412A to 412C.

At operation 412A, the user device 102 is requested to provide information related to the panels if the receiving reference point and the transmitting reference point for the triggered first time difference measurement report are not the same reference points. The additional information may include, but is not limited to relative displacement between the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N; orientation of the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N; the user device’s panel capabilities (e.g., whether the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are fully symmetric, or not), panel ID, type of panel (e.g., bumper, rool), etc. In accordance with an embodiment, the indicated measurement result information comprises at least one of: displacement between the receiving reference point and the transmitting reference; the orientation of the receiving and transmitting reference points. When the user device 102 continuously reports that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different for several time difference measurements, the user device 102 may be requested to provide additional panel related information for the RTT computation.

At operation 412B, the requested panel related information is sent by the user device 102.

The user device 102 sends the additional information related to the panel associated with the triggered first time difference report only on demand, i.e., in case the user device 102 continuously reports that the transmitting reference point, such as one of the TX/RX reference points 106A-106N, and the receiving reference point, such as one of the TX/RX reference points 106A-106N, are different for several time difference measurements, despite being configured to transmit the reference signal from the reference point used to receive a given reference signal (or to receive the reference signal at the reference point used to transmit a given reference signal). Such a situation can happen if the user device 102 has only one transmitting reference point, such as one of the TX/RX reference points 106A- 106N, and one receiving reference point, such as one of the TX/RX reference points 106A- 106N, which are not fully symmetric.

At operation 412C, the RTT is computed based on the triggered first time difference report and the additional panel related information provided by the user device 102. The RTT is computed by the target device knowing the fact that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are not the same reference points.

The operations 402 to 412 are only illustrative and other alternatives can also be provided where one or more operations are added, one or more operations are removed, or one or more operations are provided in a different sequence without departing from the scope of the claims herein.

In the process of explicit indication 400, the user device 102 is configured to report the first time difference measurement and the first indicator. If the user device indicates that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are not the same reference points for the reported first time difference measurement report, the user device 102 can then be configured further such that the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are the same for the second time difference measurement report. Further, additional information related to the panels associated with the first time difference measurement report may be requested by the user device 102 on demand to compute the RTT even in the situations where the receiving reference point, such as one of the TX/RX reference points 106A-106N, and the transmitting reference point, such as one of the TX/RX reference points 106A-106N, are not the same reference points.

FIG. 5 is an exemplary illustration of a first scenario for sidelink positioning, in accordance with another embodiment of the present disclosure. With reference to FIG. 5, there is shown an exemplary scenario 500 that includes the user device 102 and the second user device 104. In this implementation, the user device 102 includes a TX/RX reference point 106A and a TX/RX reference point 106B. The second user device 104 includes a TX/RX reference point 108A and a TX/RX reference point 108B. There is further shown a first reference signal 502 (RSI) and a second reference signal 504 (RS2).

In this exemplary scenario 500, the user device 102 and the second user device 104 may be vehicles. The first reference signal 502 (RSI) refers to the signal received by the user device 102 from the second user device 104, at the receiving reference point, such as the TX/RX reference point 106A, of the user device 102. The second reference signal 504 (RS2) refers to the signal transmitted by the user device 102 to the second user device 104, from the transmitting reference point, such as the TX/RX reference point 106A, of the user device 102. The first reference signal 502 and the second reference signal 504 are used for the computation of the RTT to operate sidelink positioning of the user device 102.

In this exemplary scenario 500, the second user device 104 computes the RTT when the user device 102 reports its time difference to the second user device 104. The user device 102 is configured to measure the time difference based on the first reference signal 502 sent by the second user device 104 and the second reference signal 504 sent by the user device 102. The user device 102 receives the first reference signal 502 on its receiving reference point, such as the TX/RX reference point 106A, and transmits the second reference signal 504 from its transmitting reference point, such as the TX/RX reference point 106A. The user device 102 is triggered to report the time difference measurement. The user device 102 is configured to cancel the triggered time difference measurement report, if the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, are not the same or to send the triggered time difference measurement report, if the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, are the same. The user device 102 reports the time difference, i.e., the difference between the time of reception of the first reference signal 502 and the time of transmission of the second reference signal 504, to the second user device 104, thereby indicating that the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, are the same reference points for the user device 102. The second user device 104 then accurately computes the RTT based on the reported time difference from the user device 102 and based on the time difference between the time of transmission of the first reference signal 502 and the time of reception of the second reference signal 504 at the second user device 104. The RTT computation is performed at the second user device 104 with certainty and accuracy irrespective of how the second user device 104 receives a reference signal from the user device 102 as the second user device 104 knows the relative displacement between its own reference points, such the TX/RX reference point 108A and the TX/RX reference point 108B.

FIG. 6 is an exemplary illustration of a second scenario for sidelink positioning, in accordance with another embodiment of the present disclosure. With reference to FIG. 6, there is shown an exemplary scenario 600 that includes the user device 102 and the second user device 104. In this implementation, the user device 102 includes the TX/RX reference point 106A and the TX/RX reference point 106B. The second user device 104 includes the TX/RX reference point 108A and the TX/RX reference point 108B. There is further shown a first reference signal 602 (RSI), a second reference signal 604 (RS2), a third reference signal 606 (RS3), and a fourth reference signal 608 (RS4).

In this exemplary scenario 600, the user device 102 and the second user device 104 may be vehicles. The first reference signal 602 (RSI) refers to the signal received by the user device 102 from the second user device 104, at the receiving reference point, such as the TX/RX reference point 106A, of the user device 102. The second reference signal 604 (RS2) refers to the signal transmitted by the user device 102 to the second user device 104, from the transmitting reference point, such as the TX/RX reference point 106B, of the user device 102. The third reference signal 606 (RS3) refers to the signal received by the user device 102 from the second user device 104, at the receiving reference point, such as the TX/RX reference point 106A, of the user device 102. The fourth reference signal 608 (RS4) refers to the signal transmitted by the user device 102 to the second user device 104, from the transmitting reference point, such as the TX/RX reference point 106A, of the user device 102. The RS3 606 and the RS4 608 are used for the computation of the RTT to operate sidelink positioning of the user device 102.

In this exemplary scenario 600, the user device 102 and the second user device 104 are configured to send reference signals and determine time difference measurements. The second user device 104 computes the RTT when the user device 102 reports its time difference to the second user device 104. The user device 102 is configured to measure the time difference based on the first reference signal 602 sent by the second user device 104 and the second reference signal 604 sent by the user device 102. The user device 102 receives the first reference signal 602 on its receiving reference point, such as the TX/RX reference point 106A, and transmits the second reference signal 604 from its transmitting reference point, such as the TX/RX reference point 106B. The user device 102 is configured to report the time difference measurement and to indicate explicitly with a first indicator if the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B, are the same or not. The user device 102 reports the time difference, i.e., the difference between the time of reception of the first reference signal 602 and the time of transmission of the second reference signal 604, to the second user device 104. Along with the time difference measurement, the user device 102 also reports the first indicator to the second user device 104, thereby indicating with the first indicator that the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B, are not the same reference points for the user device 102. The user device 102 is then configured by the second user device 104 to transmit a subsequent reference signal, i.e., RS4 608, from the reference point, such as the TX/RX reference point 106A, on which it received the first reference signal 602. The user device 102 then measures the time difference with the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, being the same reference points. The user device 102 is configured to report a second time difference measurement and to indicate explicitly with a second indicator if the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, are the same or not. The user device 102 reports the second time difference, i.e., the difference between the time of reception of the RS3 606 and the time of transmission of the RS4 608, to the second user device 104. Along with the second time difference measurement, the user device 102 also reports the second indicator to the second user device 104, thereby indicating with the second indicator that the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106A, are the same reference points for the user device 102. The second user device 104 computes the RTT with certainty and accuracy based on the reported second time difference from the user device 102 and based on the time difference between the time of transmission of the RS3 606 and the time of reception of the RS4 608 at the second user device 104. The RTT computation is performed at the second user device 104 irrespective of how the second user device 104 receives a reference signal from the user device 102 as the second user device 104 knows the relative displacement between its own reference points, such the TX/RX reference point 108A and the TX/RX reference point 108B.

FIG. 7 is an exemplary illustration of third scenario for sidelink positioning, in accordance with another embodiment of the present disclosure. With reference to FIG. 7, there is shown an exemplary scenario 700 that includes the user device 102 and the second user device 104. In this implementation, the user device 102 includes the TX/RX reference point 106A and the TX/RX reference point 106B. The second user device 104 includes the TX/RX reference point 108A and the TX/RX reference point 108B. There is further shown a first reference signal 702 (RSI) and a second reference signal 704 (RS2).

The first reference signal 702 (RSI) refers to the signal received by the user device 102 from the second user device 104, at the receiving reference point, such as the TX/RX reference point 106A, of the user device 102. The second reference signal 704 (RS2) refers to the signal transmitted by the user device 102 to the second user device 104, from the transmitting reference point, such as the TX/RX reference point 106B, of the user device 102. The first reference signal 702 and the second reference signal 704 are used for the computation of the RTT to operate sidelink positioning of the user device 102.

In this exemplary scenario 700, the user device 102 and the second user device 104 are configured to send reference signals and determine time difference measurements. The second user device 104 computes the RTT when the user device 102 reports its time difference to the second user device 104. The user device 102 is configured to measure the time difference based on the first reference signal 702 sent by the second user device 104 and the second reference signal 704 sent by the user device 102. The user device 102 receives the first reference signal 702 on its receiving reference point, such as the TX/RX reference point 106A, and transmits the second reference signal 704 from its transmitting reference point, such as the TX/RX reference point 106B. The user device 102 is configured to report the time difference measurement and to indicate explicitly with a first indicator if the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B, are the same or not. The user device 102 reports the time difference, i.e., the difference between the time of reception of the first reference signal 702 and the time of transmission of the second reference signal 704, to the second user device 104. Along with the time difference measurement, the user device

102 also reports the first indicator to the second user device 104, thereby indicating with the first indicator that the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B, are not the same reference points for the user device 102. The user device 102 is configured by the second user device 104 to provide additional panel related information associated with the time difference measurement. The additional information may include, but is not limited to relative displacement between the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B; orientation of the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B; the second user device’s panel capabilities (e.g., whether the receiving reference point, such as the TX/RX reference point 106A, and the transmitting reference point, such as the TX/RX reference point 106B, are fully symmetric, or not), panel ID, type of panel (e.g., bumper, rool), etc. The second user device 104 computes the RTT with certainty and accuracy based on the reported time difference along with the additional panel related information provided by the user device 102 and based on the time difference between the time of transmission of the first reference signal 702 and the time of reception of the second reference signal 704 at the second user device 104. The RTT computation is performed at the second user device 104 irrespective of how the second user device 104 receives a reference signal from the user device 102 as the second user device 104 knows the relative displacement between its own reference points, such the TX/RX reference point 108A and the TX/RX reference point 108B.

FIG. 8 is an exemplary illustration of a fourth scenario for sidelink positioning, in accordance with another embodiment of the present disclosure. With reference to FIG. 8, there is shown an exemplary scenario 800 that includes the user device 102, the second user device 104, and a third user device 802. In this implementation, the user device 102 includes the TX/RX reference point 106A and the TX/RX reference point 106B; the second user device 104 includes the TX/RX reference point 108A; and the third user device 802 includes a TX/RX reference point 804. There is further shown a first reference signal 806 (RSI), a second reference signal 808 (RS2), a third reference signal 810 (RS3), and a fourth reference signal 812 (RS4).

The third user device 802 includes suitable logic, circuitry, and/or interfaces that is configured to establish sidelink communication with other user devices, such as the user device 102 and the second user device 104, by transmitting and receiving reference signals at the one or more transmitting or receiving reference points, such as the TX/RX reference point 804. The information obtained from the transmitted and received reference signals of the third user device 802 can be used to compute a time difference measurement report. The time difference measurements can further be used to compute a round trip time (RTT), which can be used for sidelink positioning of the third user device 802 or any other user device.

The first reference signal 806 (RSI) refers to the signal transmitted by the second user device 104 from its transmitting reference point, such as the TX/RX reference point 108A. The second reference signal 808 (RS2) refers to the signal transmitted by the user device 102 from its transmitting reference point, such as the TX/RX reference point 106A. The third reference signal 810 (RS3) refers to the signal transmitted by the user device 102 from its transmitting reference point, such as the TX/RX reference point 106B. The fourth reference signal 812 (RS4) refers to the signal transmitted by the third user device 802 from its transmitting reference point, such as the TX/RX reference point 804.

In this exemplary scenario 800, the user device 102 is configured to perform multiple time difference measurements based on multiple reference signals sent by the user device 102 and/or based on multiple reference signals sent by multiple user devices. The user device 102 is configured to perform two time difference measurements based on reference signals sent by two user devices, such as the second user device 104 and the third user device 802, and two reference signals sent by the user device 102, such as the second reference signal 808 and the third reference signal 810. The first time difference measurement is based on the first reference signal 806 sent by the second user device 104 and the second reference signal 808 sent by the user device 102 from its transmitting reference point, such as the TX/RX reference point 106A. The second time difference measurement is based on the fourth reference signal 812 sent by the third user device 802 and the third reference signal 810 sent by the user device 102 from its transmitting reference point, such as the TX/RX reference point 106B. In this case, there is a TX/RX reference point uncertainty between the multiple time difference measurements. The proposed indication whether the receiving reference point used for a reference signal reception and the transmitting reference point used for a reference signal transmission supports also the case when the reference signals are associated with different time difference measurements. The proposed indication enables to configure the transmitting and receiving reference points for a time difference based on a reference signal associated with another time difference measurement. In addition, the user device 102 could be further configured to provide information regarding the transmitting and receiving reference points of a time difference measurement.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

Claims

1. A user device (102), arranged to operate sidelink positioning, the user device 102 comprising a transceiver (114) being configured to receive a first reference signal (110), RSI, at a receiving reference point and and a processor (116) being configured to trigger a first time difference measurement report to be sent by the user device (102), and a) cancel the triggered first time difference measurement report when the receiving reference point of the first reference signal (110), RSI, is different from a transmitting reference point of a second reference signal (112), RS2, and the user device (102) is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting, and/or, b) send the triggered first time difference measurement report.

2. The user device (102) according to claim 1, wherein sending the triggered first time difference measurement report comprises: sending a first time difference measurement report to indicate measurement result information; or, sending a first time difference measurement report to indicate a second time difference measurement is needed.

3. The user device (102) according to claim 1 or 2, wherein the first time difference measurement report comprises a first indicator, wherein the first indicator indicates whether the receiving reference point is the same as the transmitting reference point.

4. The user device (102) according to any of previous claims, wherein the transceiver (114) is further configured to transmit the second reference signal (112), RS2, to a second user device (104).

5. The user device (102) according to anyone of previous claims, wherein the processor (116) is further configured to: determine a first timing of the first reference signal; determine a second timing of the second reference signal; and determine a time difference between the first timing and the second timing.

6. The user device (102) according to claim 2, wherein the transceiver (114) is further configured to: receive a third reference signal, RS3, at the transmitting reference point, or, transmit a fourth reference signal, RS4, from the receiving reference point.

7. The user device (102) according to claim 2, wherein the indicated measurement result information comprises at least one of: relative displacement between the receiving reference point and the transmitting reference point, orientation of the receiving and transmitting reference points.

8. The user device (102) according to any of previous claims, wherein the first and second reference points are the same if they are within a threshold distance from one another.

9. A method (200) for a user device (102) arranged to operate sidelink positioning, wherein the method (200) comprises: receiving a first reference signal (110), RSI, at a receiving reference point; triggering a first time difference measurement report to be sent by the user device (102), and a) cancelling the triggered first time difference measurement report when the receiving reference point of the first reference signal (110), RSI, is different from a transmitting reference point of a second reference signal (112), RS2, and the user device (102) is (pre-)configured to send the first time difference measurement report only when using a same reference point for receiving and transmitting and/or, b) sending the triggered first time difference measurement report.

10. A computer-readable medium carrying computer instructions that when loaded into and executed by a processor (116) of a user device (102) enables the user device (102) to implement the method (200) according to claim 9.