TECHNICAL FIELD

The present disclosure relates to the field of wireless communications, and in this field to sidelink transmission. The disclosure provides multiple user devices and a network device used for performing or supporting sidelink positioning, respectively.

BACKGROUND

Positioning or location services have been identified as an enabling technology for nextgeneration mobile radio networks. Given the received radio signals from another device, measurements such as time/range, Doppler shifts, angles, signal-to-noise ratio, or channel impulse/frequency response may be obtained by a device. These measurement parameters may be further utilized to derive useful information, e.g., the relative position of the devices. In case the geographical coordinates of one device are known, the position coordinates of the other device can be determined correspondingly.

In order to achieve a specific level of quality of a location service, certain levels of positioning measurement quality are to be guaranteed. The measurement performance typically relies on the positioning reference signals (PRSs). Unlike data communication, where a certain size of the time-frequency resource is allocated to convey a block of data, positioning measurements additionally require the reference signal transmission with a specific shape. The next-generation mobile radio networks aim to not only provide high-rate data transmission, but also scalable measurement capabilities, enabling services such as positioning with an arbitrary level of performance requirements. One of the key problems is to efficiently provide time-frequency resources for supporting various types of measurements.

The sidelink transmissions in the 5th generation (5G) radio access network are accommodated using resource pools. Typically, a conventional resource pool consists of contiguous frequency resources and non-contiguous time slots that have been configured for sidelink transmissions. A resource pool is defined within a sidelink Bandwidth Part (BWP) where single numerology is used. The time-frequency resources in a resource pool is further partitioned into subchannels, where a subchannel consists of a group of consecutive resource blocks in a slot. A subchannel represents the smallest unit for a sidelink data transmission or reception. A sidelink transmission can use one or multiple subchannels.

Accommodating sidelink PRS transmission using the conventional resource pool configuration may cause two main disadvantages.

Firstly, it is not optimal to accommodate PRSs of various shapes into the subchannels configured for data transmissions. Due to the different characteristics of the PRS and data blocks, it is inefficient to allocate sidelink PRSs which occupy a single time slot over a large bandwidth, or those with small bandwidth but long-time duration simultaneously using a universal resource partition. Either significant waste of resources or resource collisions may be encountered.

Secondly, since conventional resource pool configuration is designed for uni-directional sidelink data transmission, multiple resource assignments are required to complete a single positioning measurement involving bi-directional PRS transmissions such as round-trip-time. This causes unnecessary signaling and latency overhead.

SUMMARY

In view of the above, the present disclosure aims for an efficient resource assignment for supporting sidelink PRSs for various types of measurements. An objective is to avoid waste of resources or resource collisions. Another objective is to avoid unnecessary signaling and latency overhead. Another objective is to allow the resource configuration of resources to be adjusted based on specific characteristics of the positioning measurements that are to be supported. Another objective is to enable efficient resource utilization for both communications and positioning measurements. Another objective is to provide a more straightforward resource access method to reduce the signaling overhead.

These and other objectives are achieved by the solution in the independent claims. Advantageous implementations of the embodiments of the present disclosure are further defined in the dependent claims. The solution of this disclosure bases on the proposal to allocate a dedicated resource for sidelink PRS transmission and measurements, which may be different from the resource assigned for data transmission.

A first aspect of the disclosure provides a first user device for sidelink positioning, wherein the first user device is configured to: obtain a configuration of a dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtain a resource grant for transmitting and/or receiving one or more sidelink PRSs; and transmit and/or receive the one or more sidelink PRSs on the dedicated resource based on the resource grant.

By using the dedicated resource, different dedicated resources could be configured and used for different characteristics of the positioning measurements that are to be supported. By transmitting and/or receiving multiple sidelink PRSs based on the resource grant, signaling and latency overhead can be reduced. With the dedicated resource, efficient resource utilization is enabled for both communications and the positioning measurements.

In an implementation form of the first aspect, obtaining a configuration of a dedicated resource comprises: obtaining the configuration of the dedicated resource from a network device or a third user device.

For example the configuration may be received via downlink or sidelink.

In an implementation form of the first aspect, obtaining a resource grant comprises one of the following: determining the resource grant based on the configuration of the dedicated resource; receiving the resource grant from the network device or a third user device.

The resource grant may thus be obtained directly or indirectly.

In an implementation form of the first aspect, the resource grant indicates one or more subresources of the dedicated resource, which are assigned to the first user device; and the first user device is configured to transmit and/or receive the sidelink PRS on the one or more subresources of the dedicated resource. The resource grant may accordingly indicate to the first user device, which sub-resources the first user device is granted use of the dedicated resource for the sidelink PRS.

In an implementation form of the first aspect, the configuration of the dedicated resource comprises at least one of the following: resource allocation information, a resource partition within the dedicated resource; one or more transmission directions allowed by the dedicated resource, one or more access conditions for the one or more user devices to access the dedicated resource, one or more resource selection rules for the one or more user devices to select one or more sub-resources from the dedicated resource for performing the transmission and/or reception of the sidelink PRS.

In an implementation form of the first aspect, the one or more access conditions comprises one or more of the following: one or more configured measurement types; a set of configured parameter thresholds.

In an implementation form of the first aspect, the one or more resource selection rules comprises one or more of the following: a number of sub-resources that a user device is allowed to select; an indicator indicating whether bundling of multiple sub-resources is allowed in frequency and/or time dimension using a single resource grant; an indicator indicating whether a backwards sidelink PRS transmission is allowed using a single resource grant.

In an implementation form of the first aspect, the first user device is configured to: determine the resource grant based on the one or more resource selection rules.

In an implementation form of the first aspect, the resource grant comprises at least one of the following: a source identity and/or a destination identity; a time frequency resource assignment; a transmission direction indication; a resource bundling indicator.

In an implementation form of the first aspect, the time frequency resource assignment indicates one or more sub-resources of the dedicated resource, which are assigned for one or more sidelink PRS transmissions.

In an implementation form of the first aspect, transmitting and/or receiving the sidelink PRS on the dedicated resource based on the resource grant comprises: sending one or more PRSs and/or sidelink control information to a second user device on the dedicated resource based on the resource grant.

In an implementation form of the first aspect, the first user device is configured to: determine one or more sub-resources for a backwards sidelink PRS transmission, which are assigned to the second user device, based on the one or more resource selection rules.

In an implementation form of the first aspect, the sidelink control information indicates to the second user device the one or more sub-resources for the backwards sidelink PRS transmission, and the first user device is further configured to: receive the backwards PRS transmission from the second user device.

A second aspect of the present disclosure provides a second user device for sidelink positioning, wherein the second user device is configured to: obtain a configuration of a dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtain a resource grant for receiving and/or transmitting one or more sidelink PRSs, from a third user device, or from sidelink control information received from a first user device; and receive the one or more sidelink PRSs and/or the sidelink control information from the first user device on the dedicated resource based on the resource grant.

By using the dedicated resource, different dedicated resources could be configured and used for different characteristics of the positioning measurements that are to be supported. By transmitting and/or receiving multiple sidelink PRSs based on the resource grant, signaling and latency overhead can be reduced. With the dedicated resource, efficient resource utilization is enabled for both communications and the positioning measurements.

In an implementation form of the second aspect, obtaining a configuration of a dedicated resource comprises: obtaining the configuration of the dedicated resource from a network device, a first user device, or a third user device.

In an implementation form of the second aspect, the resource grant comprises at least one of the following information: a source identity and/or a destination identity; a time frequency resource assignment; a transmission direction indication; a resource bundling indicator. In an implementation form of the second aspect, the time frequency resource assignment indicates one or more sub-resources of the dedicated resource, which are assigned for one or more sidelink PRS transmissions.

In an implementation form of the second aspect, the sidelink control information indicates to the second user device one or more of the information in the resource grant.

In an implementation form of the second aspect, the second user device further configured to: send a backwards PRS to the first user device on one or more sub-resources for a backwards sidelink PRS transmission based on the resource grant.

A third aspect of the present disclosure provides a third user device for supporting sidelink positioning, wherein the third user device is configured to: obtain a configuration of a dedicated resource from a network device, wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtain a resource grant for transmitting and/or receiving one or more sidelink PRSs; and provide at least a first part of the resource grant to a first user device and/or provide at least a second part of the resource grant to a second user device, wherein the first user device and the second user device are involved in the sidelink positioning.

By using the dedicated resource, different dedicated resources could be configured and used for different characteristics of the positioning measurements that are to be supported. By transmitting and/or receiving multiple sidelink PRSs based on the resource grant, signaling and latency overhead can be reduced. By providing a part of the resource grant to another user device, resource coordination is enabled among multiple user devices, thus resource collisions can be avoided when transmitting or receiving the sidelink PRSs.

In an implementation form of the third aspect, obtaining a resource grant comprises: determining the resource grant based on the configuration of the dedicated resource, or receiving the resource grant from the network device.

In an implementation form of the third aspect, providing at least a first part of the resource grant to a first user device and/or provide at least a second part of the resource grant to a second user device comprises: sending sidelink control information to the first user device and/or the second user device, wherein the sidelink control information indicates to the first user device and/or the second user device one or more sub-resources for a sidelink PRS transmission and/or a backwards sidelink PRS transmission.

A fourth aspect of the present disclosure provides a network device, for supporting sidelink positioning, wherein the network device is configured to: configure a dedicated resource for one or more user devices, wherein the resource is dedicated for transmitting and/or receiving sidelink positioning reference signals, PRSs; and provide a configuration of the dedicated resource to the one or more user devices.

By determining the dedicated resource, and providing the configuration, the network device may configure resource according to different characteristics of the positioning measurements that are to be supported. With the dedicated resource, efficient resource utilization is enabled for both communications and the positioning measurements. This may support the user devices to avoid resource collisions and reduce waste of resources, when the user devices use/exchange the sidelink PRSs.

In an implementation form of the fourth aspect, the configuration of the dedicated resource comprises at least one of the following: resource allocation information; a resource partition within the dedicated resource; one or more transmission directions allowed by the dedicated resource; one or more access conditions for the one or more user devices to access the dedicated resource; one or more resource selection rules for the one or more user devices to select one or more sub-resources from the dedicated resource for performing the transmission and/or reception of the sidelink PRSs.

In an implementation form of the fourth aspect, the one or more access conditions comprises one or more of the following: one or more configured measurement types; a set of configured parameter thresholds.

In an implementation form of the fourth aspect, the one or more resource selection rules comprises one or more of the following: a number of sub-resources that a user device is allowed to select; an indicator indicating whether bundling of multiple sub-resources is allowed in frequency and/or time dimension using a single resource grant, an indicator indicating whether a backwards sidelink PRS transmission is allowed using a single resource grant. In an implementation form of the fourth aspect, configuring the dedicated resource for the one or more user devices comprises: configuring the dedicated resource based on a type of a sidelink positioning measurement that is to be obtained using the sidelink PRSs.

In an implementation form of the fourth aspect, the type of the sidelink positioning measurement comprises at least one of the following: Round-Trip-Time (RTT) measurement, time of arrival measurement, time difference of arrival measurement, range or distance measurement, angle information measurement, frequency measurement, Doppler measurement, frequency variation measurement, or phase measurement.

In an implementation form of the fourth aspect, the network device is configured to: determine the resource partition within the dedicated resource based on the type of the sidelink positioning measurement.

In an implementation form of the fourth aspect, the network device is configured to: configure a first dedicated resource based on a first type of the sidelink positioning measurement; and configure a second dedicated resource based on a second type of the sidelink positioning measurement.

In an implementation form of the fourth aspect, the network device is configured to provide a resource grant to a first user device or a third user device of the one or more user devices, wherein the resource grant indicates one or more sub-resources of the dedicated resource that are assigned to the one or more user devices.

In an implementation form of the fourth aspect, the resource grant comprises one or more of the following: a source identity and/or a destination identity; a time frequency resource assignment; a transmission direction indication; a resource bundling indicator.

Accordingly the disclosure further proposes the network device that is used for sidelink configuration for the user devices, for instance of either of the former aspects. The network device of the fourth aspect may, for instance, support the device of the first aspect in determining, whether to transmit the sidelink PRS of the sidelink. The network device of the fourth aspect may also influence the device of the first aspect in its determination. For instance, the configuration information may support or influence the device of the first aspect in this respect.

A fifth aspect of the present disclosure provides a method performed by a first user device for sidelink positioning, comprising: obtaining a configuration of a dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtaining a resource grant for transmitting and/or receiving one or more sidelink PRSs; and transmitting and/or receiving the one or more sidelink PRSs on the dedicated resource based on the resource grant.

The method of the fifth aspect may have implementation forms that correspond to the implementation forms of the first user device of the first aspect. The method of the fifth aspect and its implementation forms provide the same advantages and effects as described above for the first user device of the first aspect and its respective implementation forms.

A sixth aspect of the present disclosure provides a method performed by a second user device for sidelink positioning, comprising: obtaining a configuration of a dedicated resource , wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtaining a resource grant for receiving and/or transmitting one or more sidelink PRSs, from a third user device, or from sidelink control information received from a first user device; and receiving the one or more sidelink PRSs and/or the sidelink control information from the first user device on the dedicated resource based on the resource grant.

The method of the sixth aspect may have implementation forms that correspond to the implementation forms of the second user device of the second aspect. The method of the sixth aspect and its implementation forms provide the same advantages and effects as described above for the second user device of the second aspect and its respective implementation forms.

A seventh aspect of the disclosure provides a method performed by a third user device for supporting sidelink positioning, comprising: obtaining a configuration of a dedicated resource from a network device, wherein the dedicated resource is allocated for transmitting and/or receiving sidelink PRSs; obtaining a resource grant for transmitting and/or receiving one or more sidelink PRSs; and providing at least a first part of the resource grant to a first user device and/or providing at least a second part of the resource grant to a second user device, wherein the first user device and the second user device are involved in the sidelink positioning.

The method of the seventh aspect may have implementation forms that correspond to the implementation forms of the third user device of the third aspect. The method of the seventh aspect and its implementation forms provide the same advantages and effects as described above for the third user device of the third aspect and its respective implementation forms.

An eighth aspect of the disclosure provides a method performed by a network device for supporting sidelink positioning, comprising: configuring a dedicated resource for one or more user devices, wherein the resource is dedicated for transmitting and/or receiving sidelink PRSs; and providing a configuration of the dedicated resource to the one or more user devices.

The method of the eighth aspect may have implementation forms that correspond to the implementation forms of the network device of the fourth aspect. The method of the eighth aspect and its implementation forms provide the same advantages and effects as described above for the network device of the fourth aspect and its respective implementation forms.

A ninth aspect of the disclosure provides computer readable code instructions which, when run in a computer will cause the computer to perform the method according to the fifth aspect and any implementation forms of the fifth aspect, the sixth aspect and any implementation forms of the sixth aspect, the seventh aspect and any implementation forms of the seventh aspect, or the eighth aspect and any implementation forms of the eighth aspect.

A tenth aspect of the present disclosure provides computer program code instructions, being executable by a computer, for performing the method according to the fifth aspect and any implementation forms of the fifth aspect, the sixth aspect and any implementation forms of the sixth aspect, the seventh aspect and any implementation forms of the seventh aspect, or the eighth aspect and any implementation forms of the eighth aspect.

It has to be noted that all devices, elements, 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 that 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.

BRIEF DESCRIPTION OF DRAWINGS

The above described aspects and implementation forms of the present disclosure will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 shows positioning measurements based on a sidelink radio transmission.

FIG. 2 shows a conventional resource pool and its subchannels for sidelink communications.

FIG. 3 shows accommodating PRSs for different types of positioning measurements using a conventional resource pool.

FIG. 4 shows a first user device according to an embodiment of the present disclosure.

FIG. 5 shows a second user device according to an embodiment of the present disclosure.

FIG. 6 shows a third user device according to an embodiment of the present disclosure. FIG. 7 shows a network device according to an embodiment of the present disclosure.

FIG. 8 shows dedicated resource pools according to embodiments of the present disclosure.

FIG. 9 shows a sidelink positioning procedure according to an embodiment of the present disclosure.

FIG. 10 shows signaling for sidelink PRSs transmissions according to an embodiment of the present disclosure.

FIG. 11 shows signaling for sidelink PRSs transmissions according to an embodiment of the present disclosure.

FIG. 12 shows dedicated resource pools according to an embodiment of the present disclosure.

FIG. 13 shows signaling for a sidelink PRSs transmission according to an embodiment of the present disclosure. FIG. 14 shows a method according to an embodiment of the present disclosure.

FIG. 15 shows a method according to an embodiment of the present disclosure.

FIG. 16 shows a method according to an embodiment of the present disclosure.

FIG. 17 shows a method according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Illustrative embodiments of various user devices, a network device, and corresponding methods for sidelink positioning, for instance in a communication system, are described with reference to the figures. Although this description provides a detailed example of possible implementations, it should be noted that the details are intended to be exemplary and in no way limit the scope of the application.

Moreover, an embodiment/example may refer to other embodiments/examples. For example, any description including but not limited to terminology, element, process, explanation, and/or technical advantage mentioned in one embodiment/example is applicative to the other embodiments/examples.

FIG. 1 shows positioning measurements based on the sidelink radio transmissions between two user devices. Notably, given the received radio signals from another device, measurements such as time/range, Doppler shifts, angles, signal-to-noise ratio, or channel impulse/frequency response may be obtained. These measurement parameters may be further utilized to derive useful information, e.g., the relative position of the devices. In case the geographical coordinates of one device are known, the position coordinates of the other can be determined correspondingly.

As previously described, unlike the data communication where a certain size of the timefrequency resource is allocated to convey a block of data, positioning measurements may additionally require the reference signal transmission with a specific shape. For instance, achieving time/range measurements with fine resolution requires high bandwidth reference signals; acquiring certain velocity/Doppler shift resolution requires time-continuous reference signal so that the channel variation in time can be tracked; measuring angular related information requires multiple reference signal transmissions with spatial directional manipulations, e.g., beam switching. FIG. 2 shows a conventional resource pool used for sidelink transmissions in the 5G radio access network. It can be seen that each resource pool comprises contiguous frequency resources and non-contiguous time slots that have been configured for sidelink transmissions. The time-frequency resource in a resource pool is partitioned into subchannels, where a subchannel consists of a group of consecutive resource blocks in a slot. A subchannel represents the smallest unit for a sidelink data transmission or reception. A sidelink transmission can use one or multiple subchannels.

FIG. 3 shows an accommodating sidelink PRS transmission using the conventional resource pool configuration. Several examples of PRS for positioning measurements typically considered for sidelink positioning are illustrated in FIG. 3.

It can be seen that the PRSs may be of various shapes based on the type of measurement. As shown in FIG. 3, the subchannels in a given resource pool may be spread over the same bandwidth and time duration. Due to the different characteristics of the PRS and data blocks, it may be inefficient to allocate sidelink PRSs, which occupy a single time slot over a large bandwidth, or those with small bandwidth but long-time duration simultaneously using a universal resource partition. This may cause significant waste of resources or cause resource collisions when accommodating PRSs of various shapes into the subchannels configured for data transmission, as illustrated in FIG. 3.

FIG. 4 shows a first user device 400, which may be used for sidelink positioning, according to an embodiment of the disclosure. The first user device 400 may be a terminal device, or a user equipment (UE), for instance, a mobile phone or a UE deployed in a vehicle.

The first user device 400 is configured to obtain a configuration 401 of a dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving one or more sidelink PRSs 402. The first user device 400 may identify and use the dedicated resource based on the configuration 401. For example, the first user device 400 may receive the configuration 401 from a network device 410 (shown in dashed lines in FIG. 4 for being optional), like a base station device.

The first user device 400 is further configured to obtain a resource grant 404 for transmitting and/or receiving one or more sidelink PRSs 402. The resource grant 404 is particularly for transmitting and/receiving the one or more sidelink PRSs on the dedicated resource. The first user device 400, for example, may receive the resource grant 404 from the network device 410. Then, the first user device 400 is configured to transmit and/or receive the one or more sidelink PRSs 402 on the dedicated resource based on the resource grant 404.

Accordingly, this disclosure proposes allocating a dedicated resource for sidelink PRS 402 transmission and measurements, wherein the dedicated resource may be different from a resource that is assigned for (sidelink) data transmission. The dedicated resource may be allocated to only one specific user device (e.g., only to the first user device 400 in this case), or may be shared among multiple user devices. That is, multiple dedicated resources may be configured in this disclosure, wherein each dedicated resource is allocated to one or more user devices. An example of a dedicated resource may include a resource pool, a measurement gap, a BWP, a sub-frequency band, or any subset of available resources for radio transmissions. Each dedicated resource may be configured for carrying out a specific type of sidelink positioning measurement. If there are different types of sidelink position measurements, multiple corresponding dedicated resources can be configured and used.

Optionally, the configuration 401 of the dedicated resource may accordingly comprise at least one of the following: resource allocation information; a resource partition within the dedicated resource; one or more transmission directions allowed by the dedicated resource; one or more access conditions for the one or more user devices to access the dedicated resource; one or more resource selection rules for the one or more user devices to select one or more sub-resources from the dedicated resource for performing the transmission and/or measurement of the sidelink PRS. The one or more access conditions may comprise one or more pre-configured measurement types and/or a set of pre-configured parameter thresholds.

Optionally, the one or more resource selection rules may comprise one or more of the following: a number of sub-resources that a user device is allowed to select; an indicator indicating whether bundling of multiple sub-resources is allowed in frequency and/or time dimension using a single resource assignment; an indicator indicating whether a backwards sidelink PRS transmission is allowed using a single resource assignment. Further details about the configuration 401 of the dedicated resource will be provided further below. The configuration 401 of the dedicated resource may be performed by a network device 410 as also explained below.

According to an embodiment of this disclosure, the first user device 400 may be configured to determine the resource grant 404 based on the one or more resource selection rules. For each resource grant 404, a subset of resources in the dedicated resource may be assigned to the first user device 400 for sidelink PRS transmission and/or reception. This resource grant 404 may be received dynamically on the downlink control channel from a RAN node (network device), or may be configured semi-persistently using RRC protocols, or may be autonomously selected by the first user device 400. In case the resource grant 404 is determined by the first user device 400, the first user device 400 may be either the sidelink PRS transmitter or the sidelink PRS receiver or neither of the two. This means a third user device may obtain one or multiple resource grants 404 for the first user device 400 and a second user device, which are involved in sidelink PRS transmission and/or reception.

The resource grant 404 may determine the resource assigned for one or multiple sidelink PRS transmissions. The resource grant 404 may be included in the sidelink control information and carried on the sidelink control channel. The resource grant 404 may comprise one or multiple of the following aspects:

1. Source identity and/or destination identity: this may indicate the transmitting and the receiving user device of the granted sidelink PRS transmission. In case a backwards transmission is required, the receiving user device may be informed that the destination of the backwards transmission is the transmitter of the forward PRS.

2. Time-frequency resource assignment: this may indicate the time and/or frequency resource that the sidelink PRS(s) occupy. The resource assignment may be indicated by indices in the time dimension e.g. symbol indices or slot indices, and/or by indices in the frequency dimension, e.g. subcarrier indices or resource block indices. It may be represented using indices of pre-configured subchannels, which represent a specific resource partition according to the specific positioning measurement characteristics supported by the dedicated resource. In particular, the pre-configured subchannels may contain pre-defined sidelink PRSs. A time- frequency resource assignment may indicate resources for multiple PRS transmission instances in both forwards and backwards directions.

3. Transmission direction indication: the granted time-frequency resource may be utilized for forwards and/or backwards sidelink PRS transmission instances. The transmission direction for each instance may be indicated in the resource grant. The forwards direction corresponds to the user device with the source identity transmitting. The backwards direction is for the user device with the destination identity transmitting. The destination user device may therefore be informed that a backwards transmission on the granted resource is required. One bit indicator may be carried in the resource grant 404, e.g. 0 for forwards transmission, 1 for backwards.

4. Resource bundling indicator: a resource grant 404 may consist of resource assignments of multiple PRS instances, each of which may carry individual control information. An indicator may be used to indicate that one or multiple subsequent PRS instances are reserved by the current resource grant.

Notably, this disclosure introduces a newly designed resource grant 404 for the dedicated resource, which supports multiple bi-directional sidelink PRS transmissions. This reduces latency and signaling overhead for a user device to obtain resource grants 404 for multiple PRS transmissions, especially for the RTT measurements where bi-directional PRS transmissions are required. It potentially also reduces the time for obtaining positioning measurements, since less time and signaling is required for obtaining the PRSs, leading to reduced active time and lower power consumption for low-energy devices. Since multiple PRS instances in both directions can be assigned using one resource grant 404, potential collisions of subsequent PRS transmissions can be avoided.

FIG. 5 shows a second user device 500, which may be used for sidelink positioning, according to an embodiment of the disclosure. The second user device 500 may be a terminal device, or a UE, for instance, a mobile phone or a UE deployed in a vehicle.

The second user device 500 is configured to obtain a configuration 401 of the dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving one or more sidelink positioning reference signals, PRSs 402. The second user device 500 may obtain the configuration 401 from the first user device 400 (shown in dashed lines in FIG. 5 for being optional), or may receive the configuration 401 from the network device 410, or may receive the configuration 401 from a third user device 600 (see, e.g., FIG. 6).

Further, the second user device 500 is configured to obtain a resource grant 404 for receiving and/or transmitting one or more sidelink PRSs. The second user device 500 may receive the resource grant 404 from a third user device 600, or may derive the resource grant 404 from sidelink control information received from the first user device 400 (as exemplarily illustrated in FIG. 5). For example, the sidelink control information may indicate to the second user device 500 one or more of the information in the resource grant 404. The second user device 500 may derive the resource grant 404 from this one or more of the information in the resource grant 404. The resource grant 404 may be for a sub-resource, which may be used for sidelink PRS transmission and reception.

Further, the second user device 500 is configured to receive the one or more sidelink PRSs 402 and/or the sidelink control information, for example from the first user device 400 (as exemplarily illustrated in FIG. 5), on the dedicated resource based on the resource grant 404.

FIG. 6 shows a third user device 600, which may be used for sidelink positioning, according to an embodiment of the disclosure. The third user device 400 may be a terminal device, or a UE, for instance, a mobile phone or a UE deployed in a vehicle.

The third user device 600 is configured to obtain a configuration 401 of a dedicated resource from the network device 410. The dedicated resource is allocated for transmitting and/or receiving sidelink PRSs.

The third user devise 600 is further configured to obtain a resource grant 404 for transmitting and/or receiving one or more sidelink PRSs 402. For example, the third user device 600 may determine the resource grant 404 based on the configuration 401 of the dedicated resource, or may receive the resource grant 404 from the network device 410. The resource grant 404 may indicate to the third user device 600 that a sub-resource on the dedicated resource may be used for sidelink PRS transmission and reception.

The third user device 600 is further configured to provide at least a first part 601 of the resource grant 404 to a first user device 400, and/or to provide at least a second part 602 of the resource grant 400 to a second user device 500. The first user device 400 and the second user device 500 are involved in the sidelink positioning, and may be the two user devices shown in FIG. 4 and FIG. 5, respectively.

FIG. 7 shows a network device 410 for sidelink positioning according to an embodiment of the disclosure. The network device 410 may be a base station device or a base-station-like device. For example, the network device 410 may be a RAN node. The network device 410 may be the one shown in any of the previous figures.

The network device 410 is configured to configure a dedicated resource for one or more user devices. Notably, the resource is dedicated to transmitting and/or receiving one or more sidelink PRSs. Further, the network device 410 is configured to provide a configuration 401 of the dedicated resource to the one or more user devices, for example, to the first user device 400, to the second user device 500, and/or to the third user device 600. That is, the one or more user devices may include at least one of the first user device 400, the second user device 500, and the third user device 600.

This disclosure proposes configuring and allocating one or more dedicated resources for sidelink PRS transmission and measurements, which may each be different from one or more resources that are assigned for data transmission. Each dedicated resource configured, for example, by the network device 410, may be allocated to a specific user device, for instance, specifically to the first user device 400, to the second user device 500, or to the third user device 600. However, any dedicated resource may also be shared among multiple user devices, for instance, among two or all three of the first user device 400, the second user device 500, and the third user device 600. Examples of such dedicated resources may include resource pools, measurement gaps, BWPs, sub-frequency bands, or any subset of the available resource for radio transmissions.

Possibly, each dedicated resource may be configured for carrying out a specific type of sidelink positioning measurement. The configuration 401 of this dedicated resource, as described for instance with respect to the previous figures, particularly the network device 410, may include the following aspects: 1. Resource allocation information: Resource allocation information may comprise the indication of the time and frequency resource allocated to the dedicated resource. The dedicated resource may be either contiguous or incontiguous in time and/or frequency. The dedicated resource may also be applied to a specific geographical zone, or to a specific spatial direction according to a pre-defined coordinate system, e.g., global coordinate system or relative to a local reference point.

2. Resource partition within the dedicated resource: The resource partition within the dedicated resource may correspond to the characteristics of the specific positioning measurement type, for instance, allowing for a finer granularity resource assignment such as symbol level assignment within a time slot, resource block level within a subchannel or subcarrier level within a resource block. This may be implemented as pre-defined reference signals or finer granularity resource sub-blocks which can be dynamically assigned or semi- persistently configured to or autonomously selected by the user devices 400, 500, 600.

3. Transmission directions allowed by the dedicated resource: Unlike the resource pools designed for sidelink communications, where only transmission or reception is allowed, some measurement types for positioning may comprises multiple measurement instances including both transmission and reception. One typical example is the RTT measurement. Hence, the dedicated resource for sidelink positioning measurement may allow resource assignments for multiple sidelink PRS transmissions including both forwards and backwards directions. This aims to support, for example, the two/three/four-way RTT measurements, frequency difference of arrival, and/or angular information measurements where antenna switching between multiple measurements are involved. FIG. 8 (a) provides an example of a dedicated resource chunk allocated for RTT measurements, where bi-directional wideband PRS transmissions of different UEs can be supported FIG. 8 (b) gives an example of a dedicated resource chunk allocated for Doppler measurements, where channel tracking over time is enabled for different UEs.

4. Access conditions: The configuration 401 of the dedicated resource may also include information indicating the conditions that a user device must fulfill while accessing the resource. Examples of such information include: a) Pre-configured measurement types including but not limited to time-related measurements such as RTT, Time-of- Arrival (To A) or Time Difference of Arrival (TDoA), angle related measurements such as Angle-of-Departure (AoD), Angle Difference of Arrival (ADoA), angle variations, or frequency variation related measurements such as Doppler shift, velocity or velocity variations, etc. The pre-configuration of the supported measurement type may be indicated using a bitmap with each bit representing a specific type of measurements supported by the dedicated resource. b) The access conditions may be represented using a set of pre-configured parameter thresholds. For instance,

• A minimum bandwidth and a maximum time spread, which results in a wide resource assignment in the frequency dimension but short in time. This applies to the dedicated resource, whose resource is partitioned for time-related measurements.

• A maximum bandwidth and a minimum time spread, which results in a wide resource assignment in the time dimension but narrow in frequency. This applies to the dedicated resource, whose resource is partitioned for frequency-related measurements.

• A minimum number of repetitions that a resource assignment supports, e.g. number of shots required for an RTT measurement, the number of beam switches resulting in an angular measurement, etc. This applies to the dedicated resource, whose resource is partitioned for multiple PRS transmission instances.

These access conditions ensure that a significant percentage of the dedicated resource is utilized.

5. Resource selection rules: If a user device 400, 500, 600 is allowed autonomous resource selection, the configuration 401 of the dedicated resource may comprise also the resource selection rules. More specifically, this may refer to the number of resource sub-blocks that a user device 400, 500, 600 is allowed to select, the indicator showing whether bundling of multiple these sub-blocks is allowed in the frequency and/or time dimension and/or whether backwards transmissions is allowed using a single resource assignment.

The configuration 401 of the dedicated resource may be determined by a RAN node (e.g., the network device 410), based on the service it supports and/or on the service required by the user devices (e.g., the first user device 400, the second user device 500, or the third user device 600) in coverage. This configuration may be provided to the user devices as system information using Radio Resource Control (RRC) protocol, LTE Positioning Protocol (LPP), or other protocols enabling communications between the network nodes 410 and user devices 400, 500, 600. The allocation of one or more dedicated resources for sidelink PRS transmission and measurements allows adjusting the resource configuration of each individual resource based on the specific characteristics of the positioning measurement each RAN node aims to support. This may lead to efficient resource utilization for both communications and positioning measurements. The configuration 401 of the dedicated resources may be determined by the RAN. This allows RAN nodes 410 to dynamically adjust the resources allocation for different types of positioning measurements based on for instance the received PRS requests, the individual capability supported, and the instantaneous traffic load. Based on the configuration of the available dedicated resources allocated for different types of PRS, user devices 400, 500, 600 may obtain resource grants for specific types of positioning measurements from the corresponding resources, leading to more straightforward resource access and reduced signaling overhead.

It may be worth mentioning that any of the first user device 400, the second user device 500, the third user device 600, and the network device 410, as above described, may comprise processing circuitry (not shown) configured to perform, conduct or initiate the various operations of the device described herein. The processing circuitry may comprise hardware and software. The hardware may comprise analog circuitry or digital circuitry, or both analog and digital circuitry. The digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors.

In one embodiment, the processing circuitry comprises one or more processors and a non- transitory memory connected to the one or more processors. The non-transitory memory may carry executable program code which, when executed by the one or more processors, causes the user device 400, 500, 600 to perform, conduct or initiate the operations or methods described herein.

For instance, the first user device 400, the second user device 500, the third user device 600, or the network device 410, may comprise a processor, a memory, and a transceiver. The memory may be configured to store executable program codes executed by the processor. The transceiver may be configured to communicate with other devices in the same network. For instance, the transceiver of the first user device 400 may be configured to transmit or receive one or more sidelink PRSs 402. The processor may be configured to execute the operations or method steps as above described in the previous embodiments.

FIG. 9 depicts a sidelink positioning procedure according to an embodiment of the disclosure.

This embodiment relates to a sidelink positioning procedure, where a dedicated radio resource is configured for sidelink PRS transmission and measurements. An example of a dedicated radio resource for sidelink PRS transmission and measurements is a dedicated resource pool. Typically, the sidelink positioning procedure involves four network entities, namely a location server 900, e.g., location management function (LMF) in a 5G core network, a RAN node (here the network device 10), and two UEs, e.g., a UE A (here the first user device 400) and a UE B (here the second user device 500).

Notably, the RAN node may particularly be the network device 410 as shown in FIG. 7, The UE A may particularly be the first user device 400 as shown in FIG. 4, and the UE B may particularly be the second user device 500 as shown in FIG. 5.

FIG. 9 provides, in particular, an exemplary sidelink positioning procedure depicted using the signaling diagram and including the following steps:

1. A sidelink location service (SL LCS) may be triggered by a location request received at the location server 900 or one of the UE A and UE B.

2a. In case the location request is received at the location server 900, the location server 900 requests sidelink positioning measurements from UE A and/or UE B and provide UE A and UE B the configuration 401 of the dedicated resource allocated for sidelink PRS transmission and reception. The dedicated resource may include, e.g., a resource pool, a subband, a carrier frequency band index, which is different from the resource used for sidelink communications.

The positioning measurement requests and/or resource configuration may be provided to the UE A and UE B as positioning assistance data. One of the UE, e.g. UE A, may be configured to obtain resource grants 404 for the required sidelink PRS transmissions by either requesting to the RAN node, to which it is attached, or by autonomous selection if resource selection rules are pre-configured for the dedicated resource. 2b. In case the location request is received for example at UE A, the UE A may provide positioning assistance data to indicate to UE B the sidelink positioning measurements required, and that sidelink PRS transmission is carried out on a dedicated resource for the sidelink positioning measurement, which is different from the resource used for sidelink communication. The dedicated resource configuration 401 may be provided to the UEs 400, 500 in advance, e.g., as system information, by the RAN node 410.

Same as in 2a), the UE A obtains resource grants 404 for the required sidelink PRS transmissions by either requesting to the RAN node, to which it is attached, or by autonomous selection if resource selection rules are pre-configured for the dedicated resource.

3. UE A sends sidelink PRSs on the dedicated resource based on the resource grants 404 obtained. UE B detects the sidelink PRS sent by UE A on the dedicated resource, and may send sidelink PRS backwards on the resource reserved by UE A based on the Sidelink Control Information (SCI) received.

4a. In case the sidelink positioning measurements are requested by the location server 900, UE A and/or UE B reports sidelink positioning measurements to the location server 900.

4b. In case the sidelink positioning measurements are requested by UE A and/or UE B, the sidelink positioning measurement reports are collected at the corresponding UE 400 or 500 as configured using the sidelink communication interface.

It should be noted that only the sidelink PRS transmission and measurements are carried on the dedicated resource. The positioning configuration and assistance data provision are based on the communication links between the corresponding entities.

As previously discussed, to efficiently provide time-frequency resources supporting various types of measurements, each dedicated resource may be configured for carrying out a specific type of sidelink positioning measurement.

FIG. 10 and FIG. 11 show sidelink PRS transmissions between UE A and UE B for obtaining different sidelink positioning measurements according to embodiments of this disclosure. Notably, UE A may again be the first user device 400 as shown in FIG. 4, and UE B may again be the second user device 500 as shown in FIG. 5.

FIG. 10 (a) shows sidelink PRS transmissions between UE A and UE B for obtaining RTT measurement. In this example, SCIs contain resource grants 404 for sidelink PRS transmissions using the dedicated resource pool allocated for RTT measurements.

In particular, UE A initiates an RTT measurement with UE B and obtains resource grants 404 for both the forwards and the backwards PRS transmissions. As shown in this figure, the dedicated resource pool contains one-symbol sidelink PRSs spread over a pre-defined block of frequency resources. In this example, UE A transmits a sidelink PRS 1 on symbol 0 and reserves a PRS 2 on symbol 3 for the backwards transmission.

The SCI transmitted together with PRS 1 may include the following information:

• Source identity: A, destination identity: B;

• Time symbols assigned for PRS transmission: [0, 3] or as a bitmap [1 0 0 1 0 0]

• Transmission direction: [0 ,1] - 0 for forwards, 1 for backwards.

UE B decodes the SCI and is informed that a PRS for RTT measurement is transmitted by UE A to UE B. Therefore, measurement is requested on the time symbol 0 and a backwards PRS should be transmitted on symbol 3 back to UE A.

FIG. 10 (b) shows sidelink PRS transmissions between UE A and UE B for obtaining a doublesided two-way ranging measurement using a dedicated resource pool for RTT measurement. In this example, resource assignments over multiple time slots are enabled.

Notably, SCIs contain resource grants enabling double-sided two-way ranging using the dedicated resource pool allocated for RTT measurements. In particular, FIG. 10 (b) shows three sidelink PRS transmissions between UE A and UE B for obtaining a double-sided two-way ranging measurement. The three sidelink PRSs are distributed in three time symbols in two time slots. In this example, UE A transmits sidelink PRS 1 on symbol 0 of slot 0 and reserves a PRS 2 on symbol 3 for the backwards transmission; it also indicates that the subsequent slot is reserved by the current resource assignment. The SCI 1 transmitted together with PRS 1 may include the following information

• Source identity: A, destination identity: B;

• Time symbols assigned for PRS transmission: [0, 3] or as a bitmap [1 0 0 1 0 0];

• Transmission direction: [0 ,1] - 0 for forwards, 1 for backwards;

• Subsequent Slot Reserved (SSR): 1 (e.g. 1 for reserved, otherwise 0).

The SCI 2 transmitted with PRS 3 may include:

• Source identity: A, destination identity: B;

• Time symbols assigned for PRS transmission: [0] or as a bitmap [1 0 0 0 0 0];

• Transmission direction: [0], where 0 for forwards, 1 for backwards;

• SSR: 0, (e.g., 1 for reserved, otherwise 0).

More generally, a resource grant may also reserve multiple time slots which are not consecutive in time. Similar to SSR, the reserved time slots for the future PRS transmissions are indicated in the SCI of each time slot containing sidelink PRS transmissions.

FIG. 11 (a) shows sidelink PRS transmissions between UE A and UE B for obtaining angle information measurements according to an embodiment of this disclosure, and a dedicated resource pool for angle information measurements.

As shown in FIG. 11 (a), the pre-allocated resource pool comprises sets of sidelink PRS instances. Each set may be assigned to a user device for sidelink PRS transmissions. For each PRS instance within a set, a different antenna or spatial filter may be used. For example, assuming four antennas are available at UE A, the four antennas with indices [0 1 2 3] may be sequentially used to transmit sidelink PRSs on the four transmission instances in the assigned set. The antenna switching sequence or spatial filters information of the assigned sidelink PRS set may be conveyed to the receiving UE using SCI.

FIG. 11 (b) shows sidelink PRS transmissions between UE A and UE B for obtaining frequency-related measurements according to an embodiment of this disclosure, and a dedicated resource pool for frequency measurements. This embodiment provides an example of dedicated resource pools allocated for Doppler/frequency variation measurements. In this example, the pre-allocated resource pool comprises sidelink PRSs spread over a pre-defined number of time symbols or slots. UE A may select one or multiple of the pre-configured sidelink PRSs within the resource pool according to the requirement of measurement performance. In this particular example shown in FIG. 11 (b), two sidelink PRSs are assigned to UE A for the frequency variation measurement between UE A and UE B.

FIG. 12 shows dedicated resource pools for RTT measurement with its Physical Sidelink Control Channel (PSCCH) according to embodiments of the disclosure. In FIG. 12, particularly, control channel designs and subchannel configuration in the dedicated resource pool for sidelink PRS are depicted.

According to the 5G new radio specification, the subchannels in the resource pools for sidelink communications consist of contiguous symbols within one time slot. In order to enable finer granularity resource assignments for sidelink positioning measurements, while preserving the subchannel definition as the minimum scheduling unit, the subchannels in the dedicated resource pool for sidelink positioning measurements may consist of the non-contiguous symbol within one slot.

The PSCCH of different subchannels within one time slot may occupy orthogonal resources, e.g., in time, frequency, or code domain. FIG. 12 provides two examples where three subchannels are defined in a dedicated resource pool for RTT measurements (Physical Sidelink Shared Channel (PSSCH) as shown in the figures) with their PSCCHs multiplexed orthogonal in time (FIG. 12 (a)) or in frequency (FIG. 12 (b)).

The subchannel configuration may be included as resource partition information of the dedicated resource pool as described in the previous embodiments. This configuration comprises the time-frequency scheduling information of the subchannels as well as the mapping information of its corresponding PSCCH. This subchannel configuration essentially provides the mapping relationship between the pre-defined sidelink PRSs and the SCI required for sidelink PRS measurements. FIG. 13 shows signaling among three UEs according to embodiments of this disclosure. In this embodiment, UE A obtains a resource grant 404 for the UE B and UE C, where UE B and UE C obtains the resource grants 404 for sidelink positioning measurements via UE A. Notably, the UE A may here be the third user device 600 as shown in FIG. 6, the UE B may be the first user device 400 as shown in FIG. 4, and the UE C may be the second user device 500 as shown in FIG. 5.

The dedicated resource configuration 401 proposed in this disclosure with the corresponding resource grant design also allows a third user device (e.g., the third user device 600) to obtain resource grants 404 for sidelink positioning PRS transmitted between another two user devices (the first user device 400 and the second user device 500), as shown in FIG. 13.

In this embodiment, UE A may obtain one or multiple resource grants 404 for positioning measurements between UE B and UE C. The resource grants 404 may be provided by a RAN node via downlink or determined by UE A autonomously based on the pre-configuration. The resource grants 404 are then provided to UE B and/or UE C using, for instance, system information, RRC message, SCI, or any other communication protocol over the sidelink interface. UE B and/or UE C receives the resource grants 404 and carries out sidelink PRS transmission or reception correspondingly.

This embodiment may for instance facilitate sidelink PRS coordination within a group of user devices, where a group head obtains sidelink resources and coordinates PRSs transmission between the user devices within the group.

FIG. 14 shows a method 1400 according to an embodiment of the present disclosure. In particular, the method 1400 is performed by a first user device 400 as shown in FIG. 4. The method 1400 may be performed for sidelink positioning.

The method 1400 comprises a step 1401 of obtaining a configuration 401 of a dedicated resource, wherein the dedicated resource is allocated for transmitting and/or receiving one or more sidelink PRSs 402. The method 1400 further comprises a step 1402 of obtaining a resource grant 404 for transmitting and/or receiving the one or more sidelink PRSs 402. The method 1400 further comprises a step 1403 of transmitting and/or receiving the one or more sidelink PRSs 402 on the dedicated resource based on the resource grant 404. FIG. 15 shows a method 1500 according to an embodiment of the present disclosure. In particular, the method 1500 is performed by a second user device 500 as shown in FIG. 5. The method 1500 may be performed for supporting sidelink positioning.

The method 1500 comprises a step 1501 of obtaining a configuration 401 of a dedicated resource, wherein dedicated resource is allocated for transmitting and/or receiving one or more sidelink PRSs 402. The method 1500 further comprises a step 1502 of obtaining a resource grant 404 for receiving and/or transmitting the one or more sidelink PRSs 402, from a third user device 600, or from sidelink control information received from a first user device 400. The method 1500 further comprises a step 1502 of receiving the one or more PRSs and/or the sidelink control information from the first user device 400 on the dedicated resource based on the resource grant 404.

FIG. 16 shows a method 1600 according to an embodiment of the present disclosure. In particular, the method 1600 is performed by a third user device 600 as shown in FIG. 6. The method 1600 may be performed for supporting sidelink positioning.

The method 1600 comprises a step 1601 of obtaining a configuration 401 of a dedicated resource from a network device 410, wherein the dedicated resource is allocated for transmitting and/or receiving one or more sidelink PRSs 402. Further, the method 1600 comprises a step 1602 of obtaining a resource grant 404 for transmitting and/or receiving the one or more sidelink PRSs 402. Further, the method 1600 comprises a step 1603 of providing at least a first part 601 of the resource grant 404 to a first user device 400 and/or providing at least a second part 602 of the resource grant 404 to a second user device 500, wherein the first user device 400 and the second user device 500 are involved in the sidelink positioning.

FIG. 17 shows a method 1700 according to an embodiment of the present disclosure. In particular, the method 1700 is performed by a network device 410 as shown in FIG. 7 or FIG. 4. The method 1700 may be performed for supporting sidelink positioning.

The method 1700 comprises a step 1701 of configuring a dedicated resource for one or more user devices 400, 500, 600, wherein the resource is dedicated for transmitting and/or receiving sidelink PRSs. The method 1700 further comprises a step 1702 of providing a configuration 401 of the dedicated resource to the one or more user devices 400, 500, 600.

The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed disclosure, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.