WO2019197036A1

WO2019197036A1 - Devices and methods for determining the position of a target user equipment

Info

Publication number: WO2019197036A1
Application number: PCT/EP2018/059536
Authority: WO
Inventors: Richard Stirling-Gallacher; Li Zhongfeng; Sandip GANGAKHEDKAR; Qi Wang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-04-13
Filing date: 2018-04-13
Publication date: 2019-10-17
Also published as: CN111566499A

Abstract

The invention relates to a target user equipment for communication in a wireless communication network. The target user equipment comprises a processor configured to: obtain availability information about position context information of one or more of a plurality of candidate user equipments, in particular in response to an initial request; select a subset of the plurality of candidate user equipments based on the availability information, in particular based on an initial response received from at least one candidate user equipment including the availability information; transmit a request to the subset based on the availability information; and determine the position of the target user equipment on the basis of the position context information from at least one user equipment of the subset. Moreover, the invention relates to a base station for determining the position of the target user equipment in the wireless communication network.

Description

DESCRIPTION

Devices and methods for determining the position of a target user equipment

TECHNICAL FIELD

In general, the present invention relates to wireless communication networks. More specifically, the present invention relates to devices and methods for determining the position of a target user equipment in a wireless communication network.

BACKGROUND

There is a strong need for accurate positioning schemes, some examples are: locating emergency callers, which is mandatory for some network operators in certain regions of the world; positioning for V2X applications such as for different levels of automated driving, traffic management and vehicle safety; and positioning for enabling location-based services (i.e. local maps or for providing a list of local services etc.)·

Conventionally, the LTE cellular system from release 8 onwards has provided positioning functionality, using Observed Time Difference of Arrival (OTDOA), uplink (U) TDOA and a variety of other techniques (e.g. enhanced cell ID (ECID)). These positioning techniques could be network or user equipment based centric techniques and may be based on downlink or uplink transmission of Position Reference Signals (PRS).

For OTDOA, as shown in figure 1 , the user equipment (UE) traditionally needs to receive from or transmit to at least three Target Reference Points (TRPs) 101 a-c, so that two different time-difference curves can intersect to determine the position of the UE.

For 5G NR (New Radio), the available frequencies used and the associated bandwidths are higher than LTE and therefore the accuracy of positioning can be potentially improved due to the decreased symbol time and increased timing accuracy. However, due to the

characteristics of the higher frequencies, (> 6 GHz), it may be challenging to obtain a reliable connection from three Target Reference Points (TRPs), as required for traditional OTDOA.

Furthermore, as accurate and reliable schemes for positioning is required for V2X

applications in 5G NR systems, it is important to fully utilize the possible support (or collaborative support) of nearby vehicles on the highway which may have different levels of positioning accuracy. Various collaboration schemes have been proposed (see US patent application 15,496,381 ; PCT/EP2018/051575), but none specifically deals with the beam forming between UEs and the aspects of multiple-panels or multiple arrays on the vehicles.

Specific top-level scenarios for cooperative positioning are introduced as follows: in a first scenario, anchored co-operating UEs are involved in positioning. In the state-of-art communication systems, "anchored" UEs refer to the UEs which have an established position e.g., via GPS or network based techniques. Anchored UEs, for instance, can receive PRS signals from 3 or more Target Reference Points (TRPs) and are willing to cooperate with the target UE. An exemplary communication system 200 according the first scenario is shown in figure 2. Here the UEs 201 a-d only receive signals from 2 TRPs and therefore could benefit from the assistance from the anchored UE 203, which has connection to 3 TRPs.

In a second scenario, non-anchored co-operating UEs are involved in positioning. Non- anchored UEs refer to the UEs which have a "partial" position estimate and are willing to cooperate with other UEs. An exemplary communication system 300 according the second scenario is shown in figure 3. Here the UEs 303a-b have a "partial" position estimate, e.g. by only receiving signals from 2 Target Reference Points (TRPs) and agree to cooperate with each other. Other non-anchored cooperating UEs could be UEs which have a "rough" GPS position estimate and would be willing to cooperate.

Instead of stating whether a UE is anchored or not, which is an undefined classification, it would be more useful for a UE to specify its position error, positional inaccuracy or variance, in order to perform cooperative positioning.

Positioning accuracy requirements for 3GPP 5G NR are discussed in the specification 3GPP TS 22.186 and summarized as follows: first, the 3GPP system shall support relative lateral position accuracy of less than 0.1 m for UEs supporting V2X application for platooning in proximity. Secondly, the 3GPP system shall support relative longitudinal position accuracy of less than 0.5 m for UEs supporting V2X application for platooning in proximity.

To achieve these tight requirements, a 5G NR signaling scheme is needed to support user cooperation for positioning, so that UEs with different positioning capabilities and

inaccuracies can cooperate. Furthermore, since 5G NR will use beam-forming for the UE-to- UE connection (i.e. side link), there is a need for supporting beam-forming to/from at least one panel/array on the target UE and the chosen cooperating UE and then selecting the correct beam direction for transmission.

In light of the above, there is a need for improved devices and methods for determining the position of a target user equipment in a wireless communication network.

SUMMARY

It is an object of the invention to provide improved devices and methods for determining the position of a target user equipment in a wireless communication network.

The foregoing and other objects are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

Generally, embodiments of the invention relate to a target user equipment (UE) and a base station as well as corresponding methods to determine the position of the target user equipment in an accurate manner. More specifically, embodiments of the invention can provide a signaling scheme for 5G NR and the respective signal payloads to enable user cooperation for positioning, so that UEs with different positioning capabilities and inaccuracies can cooperate by first sharing their position capabilities, position error and furthermore their ability to configure any additional extra reference signals, i.e. SRS

(sounding reference signals), PRS (position reference signals) for relative positioning.

The capabilities and positioning errors of possible candidate cooperating UEs can be signaled according to embodiments, so that the target UE, can decide which UEs to select and how to weight or combine the position estimates of these cooperating UEs and also to decide if any further action is necessary, e.g., configuration and transmission of PRS (position reference signals) for collaborating UEs.

According to embodiments, the signaling scheme for 5G NR can support beam-forming to/from at least one panel on the target UE and the chosen cooperating UE and can select the correct beam direction for transmission. The scheme is suitable for beam-formed UE-to- UE (beam formed V2V) links and can be used with or without beam correspondent UEs (the signaling of UE panels / beam groups is therefore optional.) The improved position estimate of the target UE can be used and/or requested by the target UE or the network. More specifically, according to a first aspect the invention relates to a target user equipment for communication in a wireless cellular communication network. The target user equipment comprises a processor configured to: obtain availability information about position context information of one or more of a plurality of candidate user equipments, in particular in response to an initial request (herein also referred to as "CP initial request"); select a subset of the plurality of candidate user equipments based on the availability information, in particular based on an initial response (herein also referred to as "CP initial response”) received from at least one candidate user equipment including the availability information; transmit a request (herein also referred to as "CP Tx request") to the subset of the plurality of candidate user equipments based on the availability information; and determine the position of the target user equipment on the basis of the position context information from at least one candidate user equipment of the subset of the plurality of candidate user equipments. The initial request, i.e. the "CP initial request", can be transmitted to one or more of the plurality of candidate user equipments, an access network of the wireless communication network, a core network of a wireless communication network, and/or a remote communication device outside of the wireless communication network, such as a cloud server.

In a further possible implementation form of the first aspect, the processor is configured to obtain the availability information in response to the initial request, wherein the initial request, i.e. the "CP initial request", contains an identifier of the target user equipment and/or an identifier of a respective candidate user equipment, in particular a device ID, a beam group ID, a beam ID or a port ID.

In a further possible implementation form of the first aspect, the availability information is received by a serving base station of the wireless communication network. The serving base station can be, for instance, a remote radio head (RRH), a road side unit (RSU), a transmit and receive point (TRP), a gNB, an eNB and the like.

In a further possible implementation form of the first aspect, the processor is configured to determine the position of the target user equipment on the basis of the received position context information from at least one of the candidate user equipments using an Observed Time Difference of Arrival (OTDOA) technique.

In a further possible implementation form of the first aspect, the processer is configured to determine the position of the target user equipment on the basis of the received position context information from at least one of the plurality of candidate user equipments and one or more received reference signals, in particular a position-based reference signal, PRS, and/or a sounding reference signal, SRS.

In a further possible implementation form of the first aspect, the position context information from each of the respective candidate user equipments comprises one or more of the following: a variance or inaccuracy of the position information of the respective candidate user equipment; one or more indicators of the resources used for a reference signal by the respective candidate user equipment; information about the source of the position information of the respective candidate user equipment; and/or a reference signal of the respective candidate user equipment.

According to a second aspect the invention relates to a method for determining a position of a target user equipment configured to communicate with a plurality of candidate user equipments in a wireless cellular communication network. The method comprises the following steps performed by the target user equipment: obtaining availability information about position context information of one or more of the plurality of candidate user equipments, in particular in response to an initial request ("CP initial request"); selecting a subset of the plurality of candidate user equipments based on the availability information, in particular based on an initial response ("CP initial response") received from at least one candidate user equipment of the plurality of candidate user equipments including the availability information; transmitting a request ("CP Tx request") to the subset of the plurality of candidate user equipments based on the availability information; and determining the position of the target user equipment on the basis of the position context information from at least one candidate user equipment of the subset of the plurality of candidate user equipments.

According to a third aspect the invention relates to a base station for a wireless cellular communication network. The base station comprises a processor configured to:

communicate with a plurality of user equipments, including a target user equipment and a plurality of candidate user equipments; select a subset of the plurality of candidate user equipments based on availability information, in particular based on an initial response ("CP initial response") received from at least one candidate user equipment including the availability information; and transmit a request ("CP Tx request") to the subset based on the availability information. The base station can be, for instance, a remote radio head (RRH), a road side unit (RSU) a transmit and receive point (TRP), a gNB, an eNB and the like.

In a further possible implementation form of the third aspect, the respective request ("CP Tx request") is configured to trigger the respective candidate user equipment to send a respective further response (herein also referred to as "CP Tx response") to the target user equipment, wherein the respective request ("CP Tx request") comprises information related to at least one of the following:

- position context information from the respective candidate user equipment;

- a variance or inaccuracy of the position information of the respective candidate user equipment;

- information about the source of the position information of the respective candidate user equipment; and/or

- a reference signal of the respective candidate user equipment.

In a further possible implementation form of the third aspect, the processor is further configured to send a message (herein also referred to as "CP Rx prepare message") to the target user equipment containing information for preparing the target user equipment to receive the respective position context information from the respective candidate user equipment.

In a further possible implementation form of the third aspect, the message to the target user equipment (i.e. the "CP Rx prepare message") contains at least one of the following:

- information for synchronizing a beam of the target user equipment with a beam of at least one of the selected subset of the plurality of candidate user equipments;

- an identifier of a respective candidate user equipment, in particular a device ID, a beam group ID, a beam ID or a port ID.

According to a fourth aspect the invention relates to a corresponding method of operating a base station in a wireless communication network, wherein the method comprises the following steps: communicating with a plurality of user equipments, including a target user equipment and a plurality of candidate user equipments; selecting a subset of the plurality of candidate user equipments based on availability information, in particular based on an initial response ("CP initial response") received from at least one candidate user equipment of the plurality of candidate user equipments including the availability information; and transmitting a request ("CP Tx request") to the subset of the plurality of candidate user equipments based on the availability information.

According to a fifth aspect the invention relates to a computer program comprising program code for performing the method of the second aspect and/or the method of the fourth aspect when executed on a computer.

The invention can be implemented in hardware and/or software.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments of the invention will be described with respect to the following figures, wherein:

Fig. 1 shows a schematic diagram illustrating positioning via an OTDOA (observed time difference of arrival) technique;

Fig. 2 shows a schematic diagram illustrating cooperative positioning using anchored user equipments;

Fig. 3 shows a schematic diagram illustrating cooperative positioning using non-anchored user equipments;

Fig. 4 shows a schematic diagram illustrating a wireless communication network comprising a target user equipment according to an embodiment in communication with a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 5 shows a schematic diagram illustrating a wireless communication network comprising a target user equipment according to an embodiment in communication with a plurality of candidate user equipments; Fig. 6 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment and a plurality of candidate user equipments without network assistance;

Fig. 7 shows a schematic diagram illustrating a wireless communication network comprising a target user equipment according to an embodiment in communication with a plurality of candidate user equipments;

Fig. 8 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment, a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 9 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment, a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 10 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment, a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 1 1 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment, a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 12 shows a schematic diagram illustrating aspects of the signal flow between a target communication device according to an embodiment, a base station according to an embodiment and a plurality of candidate user equipments;

Fig. 13 shows an example of direction-based assistance information provided by a serving base station according to an embodiment;

Fig. 14 shows an exemplary payload and associated data fields of a CP initial request signal as used by a target user equipment according to an embodiment and/or a base station according to an embodiment; Fig. 15 shows an exemplary payload and associated data fields of a CP initial response signal as used by a target user equipment according to an embodiment and/or a base station according to an embodiment;

Fig. 16 shows an exemplary payload and associated data fields of a CP Tx request signal as used by a target user equipment according to an embodiment and/or a base station according to an embodiment;

Fig. 17 shows an exemplary payload and associated data fields of a CP Tx response signal as used by a target user equipment according to an embodiment and/or a base station according to an embodiment;

Fig. 18 shows an exemplary table of different inaccuracies for position variance in a CP Tx response signal as used by a target user equipment according to an embodiment and/or a base station according to an embodiment;

Fig. 19 shows a schematic diagram illustrating a method for determining a position of a target user equipment in a wireless cellular communication network according to an embodiment; and

Fig. 20 shows a schematic diagram illustrating a method of operating a base station for a wireless cellular communication network according to an embodiment.

In the various figures, identical reference signs will be used for identical or at least functionally equivalent features.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and in which are shown, by way of illustration, specific aspects in which the present invention may be placed. It will be appreciated that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, as the scope of the present invention is defined by the appended claims.

For instance, it will be appreciated that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures.

Moreover, in the following detailed description as well as in the claims embodiments with different functional blocks or processing units are described, which are connected with each other or exchange signals. It will be appreciated that the present invention covers

embodiments as well, which include additional functional blocks or processing units that are arranged between the functional blocks or processing units of the embodiments described below.

Finally, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.

As will be described in more detail in the following, embodiments of the invention are related to two different key scenarios: in a first scenario the determination of the position of a target user equipment within a wireless communication network without network assistance; and in a second scenario the determination of the position of a target user equipment within a wireless communication network with network assistance. In an embodiment, the common part for both scenarios comprises six different signals: "CP initial request", "CP initial response", "CP Tx request", "CP Tx response", "CP Rx prepare" and "CP confirmation", wherein CP stands for "cooperative or collaborative positioning". More details about signaling these different signals within a communication network without or with network assistance will be further discussed in the following. Embodiments of the invention enable accurate collaborative positioning, for instance, in a 5G NR communication network by signaling capabilities and position errors of potential candidate user equipments (UEs) to a target UE which can determine a subset of user equipments for cooperating.

Embodiments of the invention can be implemented in a wireless cellular communication network 400, which has the general architecture as illustrated in figure 4. The wireless cellular communication network 400 comprises a serving base station 431 as a

representative of a plurality of base stations of the wireless communication network 400. The serving base station 431 can be, for instance, a remote radio head (RRH), a transmit and receive point (TRP), a gNB, an eNB and the like. Moreover, the wireless cellular

communication network 400 comprises a target user equipment (UE) 401 and a plurality of candidate user equipments (UEs) 403a-c configured to communicate with each other and the serving base station 431. As illustrated in figure 4, the target user equipment 401 and/or the candidate user equipments 403a-c could be, for instance, a mobile phone, a mobile communication device of a vehicle and the like.

As will be described in more detail below, the target user equipment 401 comprises a processor 401 a configured to: obtain availability information about position context information of one or more of the plurality of candidate user equipments 403a-c, in particular in response to an initial request, i.e. the "CP initial request"; select a subset of the plurality of candidate user equipments 403a-c based on the availability information, in particular based on an initial response, i.e. the "CP initial response", received from at least one candidate user equipment 403a-c including the availability information; transmit a request, i.e. the "CP Tx request", to the selected subset of the plurality of candidate user equipments 403a-c based on the availability information; and determine the position of the target user equipment 401 on the basis of the position context information from at least one user equipment 403a-c of the subset.

As illustrated in figure 4, the target user equipment 401 can further comprise a

communication interface 401 b, which is configured to communicate with the plurality of candidate user equipments 403a-c located in the vicinity of the target user equipment 401 , wherein the communication interface 403 is configured to obtain from the plurality of candidate user equipments 403a-c the availability information about the position context information which the respective candidate user equipment 403a-c can provide.

As already described above, according to the first scenario, the communication interface 401 b of the target UE 401 can be configured to transmit the initial request, i.e. the "CP initial request", to the plurality of candidate user equipments 403a-c for obtaining from the plurality of candidate user equipments 403a-c the availability information about position context information which the respective candidate user equipment 403a-c can provide. In an embodiment, the initial request can comprise an identifier of the target user equipment 401 and/or an identifier of a respective candidate user equipment 403a-c, in particular a device ID, a beam group ID, a beam ID or a port ID.

The communication interface 401 b of the target user equipment 401 can be further configured to transmit the respective request, i.e. the "CP Tx request", to the selected subset of the plurality of candidate user equipments 403a-c, in response to a respective response, i.e. the "CP initial response", received from the plurality of candidate user equipments 403ac. The request includes information about the respective position context information requested from the respective candidate user equipment 403a-c. The communication interface 401 b of the target user equipment 401 can be further configured to obtain the respective position context information from the respective candidate user equipment 403a-c by means of the respective further response, i.e. the "CP Tx response", from the respective candidate user equipment 403a-c.

The processing unit 401 a of the target user equipment 401 can be configured to determine the position of the target user equipment 401 on the basis of the respective position context information from the respective candidate user equipment 403a-c and additionally based on sidelink, uplink or downlink transmission of position reference signals, PRS, and/or sounding reference signals, SRS, e.g. using an Observed Time Difference of Arrival, OTDOA, technique.

As illustrated in figure 4 and as will be described in more detail below, the base station 431 comprises a processor or processing unit 431 a configured to: communicate with the target user equipment 401 and the plurality of candidate user equipments 403a-c; select a subset of the plurality of candidate user equipments 403a-c based on availability information, in particular based on an initial response, i.e. an "CP initial response", received from at least one candidate user equipment 403a-c including the availability information; and transmit a request, i.e. a "CP Tx request", to the selected subset of the plurality of candidate user equipments 403a-c based on the availability information.

In an embodiment, the base station 431 can comprise a communication interface 431 b configured to obtain the availability information about the position context information, which the respective candidate user equipment 403a-c can provide, by receiving the respective response, i.e. the "CP initial response", from the respective candidate user equipment 403a- c, in response to a respective initial request, i.e. the "CP initial request", transmitted by the communication interface 431 b to each of the plurality of candidate user equipments 403a-c.

In an embodiment, the communication interface 431 b of the base station 431 can be configured to transmit the respective request, i.e. the "CP Tx request", to the selected subset of the plurality of candidate user equipments 403a-c, wherein the respective request includes information about the respective position context information to be provided by the respective candidate user equipment 403a-c to the target user equipment 401 .

In an embodiment, the respective request, i.e. the "CP Tx request", is configured to trigger the respective candidate user equipment 403a-c to send a respective further response, i.e. a "CP Tx response", to the target user equipment 401 , wherein the respective further response comprises the respective position context information from the respective candidate user equipment 403a-c.

In an embodiment, the communication interface 431 b of the base station 431 is further configured to send a message ("CP Rx prepare message") to the target user equipment 401 containing information for preparing the target user equipment 401 to receive the respective position context information from the respective candidate user equipment 403a-c. In an embodiment, the message to the target user equipment 401 contains information for synchronizing a beam of the target user equipment 401 with a beam of at least one of the selected subset of the plurality of candidate user equipments 403a-c.

In an embodiment, the target user equipment 401 can determine its position on the basis of the respective position context information from the respective candidate user equipments 403a-c additionally using an Observed Time Difference of Arrival, OTDOA, technique and/or based on uplink or downlink transmission of position reference signals, PRS, and/or sounding reference signals, SRS.

Further embodiments of the target user equipment 401 and the base station 431 will be described in the following for the two scenarios, i.e. the determination of the position of the target user equipment 401 within the wireless communication network 400 with and without the assistance of the base station 431 , i.e. the network.

Figure 5 shows a schematic diagram of a further embodiment of the wireless communication network 400, wherein the target user equipment 401 and two candidate user equipments 403a, 403b are implemented in the form of vehicles as possible co-operating UEs. The neighbouring UEs (i.e. vehicles in this case) are assumed to be synchronized and beam pairing has been established between neighboring UEs to specific antenna panels. Since connectivity has already been established, the UEs can communicate with each other. As shown in figure 5, the vehicles 401 , 403a, 403b can communicate with each other via different beams.

Figure 6 shows a schematic diagram summarizing a signaling procedure for UE to UE, device to device (D2D) or vehicle to vehicle (V2V) communication without network assistance in the communication network 400 shown in figure 4 or 5. In the exemplary signal flow shown in figure 6, the vehicles i.e. the UEs are in or out of the network coverage and links between UEs have already been established. The procedure 600 shown in figure 6 comprises the following steps: Step 601 : the target UE 401 (i.e. vehicle C) decides which neighboring UEs 403a, b (i.e. other vehicles) to ask for cooperation ("candidate cooperating UEs") based on which vehicles and panels it is already synchronized to (i.e. adjacent vehicles) and if it needs the cooperation at all.

Step 602: the target UE 401 transmits a "CP initial request" to the panels of the chosen candidate cooperating UEs 403a, b (including optionally identification of panel ID / car ID / beam group ID etc.).

Step 603: The candidate cooperating UEs 403, b transmit a "CP initial response", which includes what the chosen candidate cooperating UEs 403a, b can provide, i.e. which position context information can be provided. For instance, the message contents can include:

positioning coordinates variance (or in -accuracies) of chosen panel; source of positioning (i.e. GPS, Network or other entity) indicating stability; if the cooperating car can provide beam formed reference signals for time of arrival ranging (ToA) to the target UE 401 or not; and optionally IDs (i.e. Car ID / panel ID / Beam group ID etc).

Step 604: Based on the received initial response from the candidate cooperating UEs 403a, b, the target UE 401 can decide which candidate UEs 403a, b to select and which features, i.e. position context information, to ask for.

Step 605: The target UE 401 transmits a "CP Tx request" to the selected cooperating UEs 403a, b (containing information about what the target UE 401 wants, i.e. positioning data, variance and/or transmission of BF PRS and the ID of the target UE 401 ).

Step 606: The cooperating UE 403a transmits requested data and/or reference signals (position info and & or Beam formed PRS) to the target UE 401 via a "CP response signal".

Finally, the target UE 401 can use the information to establish or improve its current position.

Since the cooperating UE 403a receives the "CP Tx request" from the target UE 401 in step 605 on a certain receiving beam (with the target UE ID), it knows which Tx beam to send the "CP response" in step 606 (assuming beam correspondence at the cooperating UE).

In another embodiment, each candidate UE 403b, c may relay the cooperative positional capabilities of its connected neighbours, as shown in figure 7. In this case, to ensure that the target UE 401 (vehicle A) knows that the signals came from a different UE than the one from which it received the request, the initial response transmitted from UE 403b (i.e. vehicle B) can contain the ID of the neighbouring UE 403c (i.e. vehicle C). Although the target UE 401 (i.e. vehicle A) may not yet be able to connect directly with this UE 403b, it may be able to in the future (or the signals can be relayed.)

As already described above, in further embodiments, signaling within the communication network 400 may be assisted by the network, e.g. by the serving base station 431 . The process may be initiated by the target UE 401 or by the serving base station 431 , which can be implemented, for instance, as a transmit and receive point (TRP), a road side unit (RSU), a gNB, a eNB or the like, and which may or may not know the capabilities of the candidate UEs 403a-c.

Figure 8 shows a schematic diagram summarizing a signaling procedure for UE to UE, device to device (D2D), or vehicle to vehicle (V2V) communication with network assistance in the wireless communication network 400 according to a further embodiment. In the embodiment shown in figure 8, the cooperating UEs 403a, b and the target UE 401 are synchronized, but the serving base station 431 does not know the capabilities of the candidate UEs 403a, b to cooperate. The procedure 800 shown in figure 8 comprises the following steps:

Step 801 : If the serving base station 431 does not have any information about the candidate UEs 403a, b, it transmits a "CP initial request" to the candidate cooperating UEs 403a, b and waits for response. (This request may be sent to each UE in series (one after another) as shown or in parallel, not shown). Alternatively, the target UE 401 can transmit the "CP initial request" to the base station 431 , which will described below in the context of the

embodiments shown in figures 10 and 1 1.

Step 802: From the received "CP initial response" in step 801 , the serving base station 431 selects UEs 403a, b which could collaborate with the target UE 401 and which services to request (i.e. ask them to send position data and inaccuracies, transmit beam formed (BF) PRS etc.).

Step 803: The serving base station 431 transmit a "CP Tx request" to the chosen set of cooperating UEs 403a from step 802. Contents of the "CP Tx request" can inform these UEs 403a which signals to transmit (i.e. position data, BF PRS etc) and where to transmit it (via the ID of the target UE 401 ).

Step 804: If the cooperation UE 403a is not yet beam-formed synchronized with the target UE 401 , the synchronization process is initialized, which will be described in more detail further below. Step 805: Once the connection between the collaborating UE 403a and the target UE 401 is established, (if it was not established before), the collaborating UE 403a can send a "CP Tx response" to the target UE 401 , based on what was requested.

Step 806: The target UE 401 can send a "CP confirmation message" to the serving base station 431 either to confirm that cooperation signals were received by the target UE 401 (optional) or to transmit the position estimate to the base station 431 if the base station 431 requests it.

Figure 9 shows a schematic diagram summarizing a signaling procedure for UE to UE, device to device (D2D), or vehicle to vehicle (V2V) communication with network assistance in the wireless communication network 400 according to a further embodiment. Unlike in the embodiment of the communication network 400 shown in figure 8, the cooperating UEs 403a, b and the target UE 401 shown in figure 9 are synchronized and the serving base station 431 already knows the capabilities of the candidate UEs 403a, b to cooperate. The procedure 900 shown in figure 9 comprises the following steps:

Step 901 : The serving base station 431 transmit a "CP Tx request" to the chosen set of cooperating UEs 403a. Contents of the "CP Tx request" can inform these UEs 403a which signals to transmit (i.e. position data, BF PRS etc) and where to transmit it (via the ID of the target UE 401 ).

Step 902: The collaborating UE 403a sends a "CP Tx response" to the target UE 401 , based on what was requested.

Step 903: The target UE 401 can send a "CP confirmation message" to the serving base station 431 either to confirm that cooperation signals were received by the target UE 401.

Figure 10 shows a schematic diagram summarizing a signaling procedure for UE to UE, device to device (D2D), or vehicle to vehicle (V2V) communication with network assistance in the wireless communication network 400 according to a further embodiment. In this embodiment, the cooperating UEs 403a, b and the target UE 401 are synchronized, and the serving base station 431 knows the capabilities of the candidate UEs 403a, b to cooperate. The procedure 1000 shown in figure 10 comprises the following steps:

Step 1001 : The target UE 401 transmits a "CP initial request" to the serving base station 431 .

Step 1002: Based on the known UE capabilities, the serving base station 431 selects UEs 403a which could collaborate with the target UE 401 and which services to request. Step 1003: The serving base station 431 transmits a "CP Tx request" to the chosen set of cooperating UEs 403a. Contents of the "CP Tx request" can inform these UEs 403a which signals to transmit (i.e. position data, BF PRS etc) and where to transmit it (via the ID of the target UE 401 ).

Step 1004: The serving base station 431 transmits a "CP Rx prepare signal" to the target UE 401 for preparing the target UE 401 to receive the "CP response" from the cooperating UE 403a.

Step 1005: Once the connection between the collaborating UE 403a and the target UE 401 is established, (if it was not established before), the collaborating UE 403a can send a "CP Tx response" to the target UE 401 , based on what was requested.

Step 1006: The target UE 401 can send a "CP confirmation message" to the serving base station 431 either to confirm that cooperation signals were received by the target UE 401 (optional) or to transmit the position estimate to the base station 431 if the base station 431 requests it.

Figure 1 1 shows a schematic diagram summarizing a signaling procedure for UE to UE, device to device (D2D), or vehicle to vehicle (V2V) communication with network assistance in the wireless communication network 400 according to a further embodiment. In this embodiment, the cooperating UEs 403a, b and the target UE 401 are synchronized, but the serving base station 431 does not know the capabilities of the candidate cooperating UEs 403a, b to cooperate. The procedure 1 100 shown in figure 1 1 comprises the following steps:

Step 1 101 : The target UE 401 transmits a "CP initial request" to the serving base station 431 .

Step 1 102, 1 103: The serving base station 431 transmits a "CP initial request" to the candidate cooperating UEs 403a, b and waits for a response.

Step 1 104: From the received "CP initial response" in step 801 , the serving base station 431 selects UEs which could collaborate with the target UE 401 and which services to request (i.e. ask them to send position data and inaccuracies, transmit beam formed (BF) PRS etc.).

Step 1 105: The serving base station 431 can transmit a "CP Tx request" to the chosen set of cooperating UEs 403a, b from step 1 102. Contents of the "CP Tx request" can inform these UEs 403a, b which signals to transmit (i.e. position data, BF PRS etc) and where to transmit it (via the ID of the target UE 401 ). Step 1 106: The serving base station 431 transmit a "CP Rx prepare signal" to the target UE 401 for preparing the target UE 401 to receive the "CP response" from the cooperating UE 403a.

Step 1 107: The collaborating UE 403a sends a "CP Tx response" to the target UE 401 , based on what was requested.

Step 1 108: The target UE 401 can send a "CP confirmation message" to the serving base station 431 to confirm that cooperation signals were received by the target UE 401.

In the case where the chosen cooperating UEs 403a-c and the target UE 401 are not synchronized, they first need to perform synchronization before cooperation can be conducted. This process is illustrated in figure 12, which comprises the following steps:

Step 1201 : The serving base station 431 transmits a "CP Tx request" to the chosen set of cooperating UEs 403a, b. Contents of the "CP Tx request" can inform these UEs 403a, b which signals to transmit (i.e. position data, BF PRS etc) and where to transmit it (via the ID of the target UE 401 ).

Step 1202: The serving base station 431 transmits a "CP Rx prepare signal" to the target UE 401 for preparing the target UE 401 to receive the "CP response" from the cooperating UE 403a.

Step 1203: The cooperating UE 403a and the target UE 401 perform synchronization before cooperation.

Step 1204: The collaborating UE 403a sends a "CP Tx response" to the target UE 401 , based on what was requested.

Step 1205: The target UE 401 can send a "CP confirmation message" to the serving base station 431 to confirm that cooperation signals were received by the target UE 401.

The process for synchronization between the chosen cooperating UE 403a and the target UE 401 may use a variation of the process explained in the patent application PCT/EP

2018/051575, which is herein fully incorporated by reference. It may also be assisted by the serving base station 431 to facilitate a more rapid beam-formed synchronization procedure. To facilitate a rapid beam-formed synchronization between UEs for this case, the serving base station 431 may provide the target UE 401 and cooperating UE extra "rough" relative position information, which could be used to turn on sync signals on specific Tx/Rx panels on the target UE 401 and cooperating UEs 403a, b.

If the position of the target UE 401 and the positions of cooperating UEs 403a, b are not known precisely by the base station 431 , the base station 431 could use the serving beams and reference signal received power (RSRP) of the UEs to get a rough estimate.

This assistance information could be a specific panel ID or beam group ID if this is known by the base station 431. This could be conveyed by the optional ID fields in the "CP Tx request" and "CP Tx request".

Alternatively, this information could be relative direction based, i.e. north, south, west, east or front, back, left, right, (requiring 2 bits), as illustrated in figure 13, which shows an example of direction-based assistance information provided by the serving base station 431 to accelerate beam-formed synchronization between chosen cooperating UE 403a and the target UE 401.

For the "CP initial request" exemplary payloads and associated data fields are shown in figure 14. This signal may be transmitted by the target UE 401 or by the serving base station 431 . It may include more than one candidate UE 403a-c.

As for the "CP Initial response", exemplary payloads and associated data fields are shown in figure 15. Options for this signal include the cooperation capabilities as mentioned above.

The velocity and trajectory of a candidate UE 403a-c may also be added to the example below. The IDs of the cooperating UE 403a-c and the target UE 401 may be optionally signaled as required.

For the relayed case in a communication network without network assistance (i.e. without assistance from the base station 431 ) all of the contents (including IDs) can be from the relayed UE (i.e. the target UE 401 ), although the message is transmitted from the candidate UE 403a-c.

Regarding the "CP Tx request", exemplary payloads and associated data fields are shown in figure 16. An extra field may be included to assist in synchronization assistance, when the target UE and cooperating UEs are not synchronized. Regarding the "CP Tx response", exemplary payload and associated data fields are shown in figure 17.

For the position variance or inaccuracy, a table can be used, i.e. 3 or 4 bits, as shown in figure 18, which comprises a number of different inaccuracies. Moreover, the table may be split separately into lateral and longitudinal inaccuracies.

As described above, the "CP Rx prepare signal" is a signal to prepare the target UE 401 to receive the "CP response signal" from the cooperating UEs 403a-b. It may optionally also contain information to assist UE-to-UE synchronization, which can comprise Panel ID / Beam Group ID / Sounding resource ID or an orientation indicator.

The "CP confirmation signal" is a signal to inform the serving base station 431 that the cooperation between the assigned cooperating UE 403a-c and the target UE 401 has occurred. It may include the IDs of these UEs. Optionally it may communicate the updated position estimate of the target UE 401 if the base station 431 has requested it.

Figure 19 shows a schematic diagram illustrating a method 1900 for determining a position of the target user equipment 401 in the wireless cellular communication network 400. The method 1900 comprises the following steps performed by the target user equipment 401 : obtaining 1901 availability information about position context information of one or more of the plurality of candidate user equipments 403a-c, in particular in response to an initial request, i.e. a "CP initial request"; selecting 1903 a subset of the plurality of candidate user equipments 403a-c based on the availability information, in particular based on an initial response, i.e. an "CP initial response", received from at least one candidate user equipment 403a-c including the availability information; transmitting 1905 a request, i.e. a "CP Tx request", to the subset based on the availability information; and determining 1907 the position of the target user equipment 401 on the basis of the position context information from at least one user equipment 403a-c of the subset. Figure 20 shows a schematic diagram illustrating a method 2000 of operating the base station 431 in the wireless communication network 400. The method 2000 comprises the following steps: communicating 2001 with a plurality of user equipments, including a target user equipment 401 and a plurality of candidate user equipments 403a-c; selecting 2003 a subset of the plurality of candidate user equipments 403a-c based on availability information, in particular based on an initial response, i.e. a "CP initial response", received from at least one candidate user equipment 403a-c including the availability information; and transmitting a request, i.e. a "CP Tx request", to the subset based on the availability information.

While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations or embodiments, such feature or aspect may be combined with one or more other features or aspects of the other implementations or embodiments as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise". Also, the terms "exemplary", "for example" and "e.g." are merely meant as an example, rather than the best or optimal. The terms“coupled” and“connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless whether they are in direct physical or electrical contact, or they are not in direct contact with each other.

Although specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent

implementations may be substituted for the specific aspects shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.

Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the invention beyond those described herein. While the present invention has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the present invention. It is therefore to be understood that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described herein.

Claims

1. A target user equipment (401 ) for communication in a wireless communication network (400), wherein the target user equipment (401 ) comprises a processor (401 a) configured to: obtain availability information about position context information of one or more of a plurality of candidate user equipments (403a-c), in particular in response to an initial request; select a subset of the plurality of candidate user equipments (403a-c) based on the availability information, in particular based on an initial response received from at least one candidate user equipment (403a-c) including the availability information; transmit a request to the subset based on the availability information; and determine the position of the target user equipment (401 ) on the basis of the position context information from at least one user equipment (403a-c) of the subset.

2. The target user equipment (401 ) of claim 1 , wherein the processor (401 a) is configured to obtain the availability information in response to the initial request, wherein the initial request contains an identifier of the target user equipment (401 ), and/or an identifier of a respective candidate user equipment (403a-c), in particular a device ID, a beam group ID, a beam ID or a port ID.

3. The target user equipment (401 ) of claim 1 or 2, wherein the availability information is received by a serving base station (431 ) of the wireless communication network (400).

4. The target user equipment (401 ) of any one of the preceding claims, wherein the processor (401 a) is configured to determine the position of the target user equipment (401 ) on the basis of the received position context information from at least one of the candidate user equipments (403a-c) and using an Observed Time Difference of Arrival, OTDOA, technique.

5. The target user equipment (401 ) of any one of the preceding claims, wherein the processer (401 a) is configured to determine the position of the target user equipment (401 ) on the basis of the received position context information from at least one of the candidate user equipments (403a-c) and one or more received reference signals, in particular a position-based reference signal, PRS, and/or a sounding reference signal, SRS.

6. The target user equipment (401 ) of any one of the preceding claims, wherein the position context information from each of the respective candidate user equipments (403a-c) comprises one or more of the following: a variance or inaccuracy of the position information of the respective candidate user equipment (403a-c), one or more indicators of the resources used for a reference signal by the respective candidate user equipment (403a-c); information about the source of the position information of the respective candidate user equipment (403a-c); and/or a reference signal of the respective candidate user equipment (403a-c).

7. A method (1900) for determining a position of a target user equipment (401 ) configured to communicate with a plurality of candidate user equipments (403a-c) in a wireless communication network (400), wherein the method (1900) comprises the following steps performed by the target user equipment (401 ): obtaining (1901 ) availability information about position context information of one or more of the plurality of candidate user equipments (403a-c), in particular in response to an initial request; selecting (1903) a subset of the plurality of candidate user equipments (403a-c) based on the availability information, in particular based on an initial response received from at least one candidate user equipment (403a-c) including the availability information; transmitting (1905) a request to the subset based on the availability information; and determining (1907) the position of the target user equipment (401 ) on the basis of the position context information from at least one user equipment (403a-c) of the subset.

8. A base station (431 ) for a wireless communication network (400), wherein the base station (431 ) comprises a processor (431 a) being configured to: communicate with a plurality of user equipments, including a target user equipment (401 ) and a plurality of candidate user equipments (403a-c); select a subset of the plurality of candidate user equipments (403a-c) based on availability information, in particular based on an initial response received from at least one candidate user equipment (403a-c) including the availability information; and transmit a request to the subset based on the availability information.

9. The base station (431 ) of claim 8, wherein the respective request is configured to trigger the respective candidate user equipment (403a-c) to send a respective further response to the target user equipment (401 ), wherein the respective request comprises information related to at least one of the following:

- position context information from the respective candidate user equipment (403a-c);

- a variance or inaccuracy of the position information of the respective candidate user equipment (403a-c);

- information about the source of the position information of the respective candidate user equipment (403a-c); and/or

- a reference signal of the respective candidate user equipment (403a-c).

10. The base station (431 ) of claim 8 or 9, wherein the processor (431 a) is further configured to send a message to the target user equipment (401 ) containing information for preparing the target user equipment (401 ) to receive the respective position context information from the respective candidate user equipment (403a-c).

1 1. The base station (431 ) of claim 10, wherein the message to the target user equipment (401 ) contains at least one of the following:

- information for synchronizing a beam of the target user equipment (401 ) with a beam of at least one of the subset of the plurality of candidate user equipments (403a-c);

- an identifier of a respective candidate user equipment (403a-c), in particular a device ID, a beam group ID, a beam ID or a port ID.

12. A method (2000) of operating a base station (431 ) in a wireless communication network (400), wherein the method (2000) comprises the following steps: communicating (2001 ) with a plurality of user equipments, including a target user equipment (401 ) and a plurality of candidate user equipments (403a-c); selecting (2003) a subset of the plurality of candidate user equipments (403a-c) based on availability information, in particular based on an initial response received from at least one candidate user equipment (403a-c) including the availability information; and transmitting (2005) a request to the subset based on the availability information.

13. A computer program product comprising program code for performing the method (1900) of claim 7 and/or the method (2000) of claim 12, when executed on a computer or a processor.