Sidelink positioning procedure handling during handover
By employing a network-assisted sidelink positioning process in a V2X environment, and utilizing the sidelink channel to continue positioning outside the coverage area, the problem of discontinuous location determination for vehicles and infrastructure equipment during handover is solved, achieving more reliable location determination and improving traffic safety and system efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2026-03-24
AI Technical Summary
In a V2X environment, the sidelink positioning process for vehicles and infrastructure equipment is susceptible to changes in coverage during handover, leading to discontinuous and inaccurate location determination, which affects traffic safety and efficiency.
By coordinating the operation of radio terminals and location management devices, network-assisted sidelink positioning is achieved. The sidelink channel is used to continue positioning outside the coverage area. The radio terminals and location management devices maintain synchronization during handover to ensure the continuity and accuracy of the positioning process.
When the radio terminal leaves the coverage area, the sidelink positioning process can be seamlessly continued, which improves the reliability and accuracy of location determination, reduces handover interruptions to location reporting, and enhances traffic safety and system efficiency.
Smart Images
Figure CN121729952A_ABST
Abstract
Description
BACKGROUND
[0001] The use of sidelink positioning in V2X environments is a promising technology in the field of intelligent transportation systems. This technology aims to provide accurate and reliable location information for vehicles and infrastructure devices to improve safety and efficiency on the road. With the increasing number of connected vehicles and the growing demand for real-time information exchange, sidelink positioning as a key solution for V2X communication is increasingly valued. SUMMARY
[0002] The problems of the prior art are solved by the radio terminal, the location management apparatus and the methods of operating the radio terminal and the location management apparatus according to the independent claims.
[0003] One aspect of the description is directed to the following subject matter: a first radio terminal comprising: at least one processor; at least one memory including computer program code; and at least one radio communication module; the at least one processor, the at least one memory, the at least one computer program code and the at least one radio communication module causing the first radio terminal to perform at least the following: receiving a request from a location management apparatus or from a second radio terminal via at least a radio channel, the request indicating that a first radio terminal attached to a first radio access node participates in at least one sidelink positioning procedure; initiating the at least one sidelink positioning procedure, wherein the at least one sidelink positioning procedure is initiated as a network assisted sidelink positioning procedure; during the sidelink positioning procedure, detaching from the first radio access node associated with a location management function, LMF, upon receiving or activating a handover trigger, wherein the handover trigger indicates a handover from the first radio access node to a second radio access node; terminating the at least one sidelink positioning procedure; and synchronizing with the second radio access node upon termination of the at least one sidelink positioning procedure.
[0004] Generally, the detachment or HO handover, trigger can be based on any one or more of the following: A) sent from the second radio to the first radio (as written here); and geographically (based on location information); and RSSI and other signal strength measurements.
[0005] Advantageously, during this exceptional out-of-coverage procedure starting from the detachment from the radio access node, the handover is handled by refraining from immediate handover in favor of completing the sidelink positioning procedure. Thus, in particular the driving safety related determination of the position or location of the vehicle or other road user can be determined with a higher level of determination confidence. The undesired interruption of the location report determination by the handover is reduced.
[0006] One advantageous example features that the first radio terminal further performs: transmitting, via the sidelink radio channel, a detach message indicating that the first radio terminal detaches from the first radio access node.
[0007] One advantageous example features that the first radio terminal further performs: detecting an indication that the first radio terminal detaches from the first radio access node, e.g. by measuring RSSI, geographical boundaries, handover conditions, etc.
[0008] It is advantageous that other radio terminals participating in the sidelink positioning procedure are informed.
[0009] One advantageous example features that the first radio terminal further performs: receiving at least one positioning message from the second radio terminal over the sidelink channel, the at least one positioning message originating from the location management apparatus.
[0010] It is advantageous that the positioning procedure can continue even in case the second radio terminal is not covered.
[0011] One advantageous example features that the first radio terminal has a target role in the at least one sidelink positioning procedure, wherein the at least one sidelink positioning procedure aims at determining position information indicative of a position of the first radio terminal having the target role, wherein the second radio terminal or at least one second radio terminal has an anchor role in the at least one sidelink positioning procedure.
[0012] One advantageous example features that the first radio terminal has an anchor role in the at least one sidelink positioning procedure, wherein the at least one sidelink positioning procedure aims at determining position information indicative of a position of the second radio terminal having the target role.
[0013] One advantageous example features that the first radio terminal further performs: selecting, upon detaching from the first radio access node, a radio terminal having the target role participating in the sidelink positioning procedure as a server of the at least one sidelink positioning procedure; and selecting or indicating a criterion for selecting at least one radio terminal having the anchor role in the sidelink positioning procedure as a respective slave of the at least one sidelink positioning procedure upon detaching from the first radio access node.
[0014] It is advantageous that the role scheme of the sidelink positioning procedure is used as a template for out-of-coverage situations. No further radio communication or selection scheme is needed to seamlessly continue the sidelink positioning procedure.
[0015] One aspect of the description is directed to the following subject matter: A method for operating a first radio terminal, the method comprising: receiving a request from a location management apparatus or from a second radio terminal via at least a radio channel, the request indicating that a first radio terminal attached to a first radio access node is participating in at least one sidelink positioning procedure; initiating the at least one sidelink positioning procedure, wherein the at least one sidelink positioning procedure is initiated as a network-assisted sidelink positioning procedure; during the sidelink positioning procedure, detaching from a first radio access node associated with a location management function, LMF, upon receiving or activating a handover trigger, wherein the handover trigger indicates a handover of the first radio access node to a second radio access node; terminating the at least one sidelink positioning procedure; and synchronizing with the second radio access node upon termination of the at least one sidelink positioning procedure.
[0016] One aspect of the description is directed to the following subject matter: A second radio terminal comprising: at least one processor; at least one memory including computer program code; and at least one radio communication module; the at least one processor, the at least one memory, the at least one computer program code, and the at least one radio communication module causing the second radio terminal to perform at least: receiving a request from a location management function or from a first radio terminal via at least one radio channel, the request indicating that a second radio terminal attached to a first radio access node is participating in at least one sidelink positioning procedure; initiating the at least one sidelink positioning procedure, wherein the at least one sidelink positioning procedure is initiated as a network-assisted sidelink positioning procedure; receiving a detach message via a sidelink radio channel indicating that a first radio terminal detached from a first radio access node; and terminating the at least one sidelink positioning procedure with at least the first radio terminal as a participant of the sidelink positioning procedure.
[0017] Advantageously, the second radio terminal is aware of the detachment of the first radio terminal and continues the sidelink positioning procedure in case the first radio terminal is in a partially covered or uncovered state. Thus, the second radio terminal is aware of an exceptional out-of-coverage positioning method in case the first radio terminal is in an exceptional out-of-coverage state.
[0018] One advantageous example is characterized in that the second radio terminal further performs: - sending a status message indicating the detachment of the first radio terminal, e.g. via an uplink channel - detecting that the first radio terminal is detaching from the first radio access node, in particular detaching from the first radio access node, by at least the first radio terminal using e.g. RSSI measurements, handover conditions, etc. and indicating a continuation of the sidelink positioning procedure.
[0019] Advantageously, status messages allow the receiving location management function to consider the detachment for its further actions.
[0020] An advantageous example is characterized in that the second radio terminal also performs, for example, sending a status message via an uplink channel, indicating that the first radio terminal has disconnected from the first radio access node and indicating the continuation of the sidelink positioning process.
[0021] An advantageous example is characterized in that the second radio terminal also performs, for example, receiving at least one location message intended for at least one first radio terminal via a downlink channel; and sending at least one location message to at least one first radio terminal via a sidelink channel.
[0022] Advantageously, a second radio terminal within the coverage area keeps the sidelink positioning process effective by forwarding at least one positioning message.
[0023] An advantageous example is characterized in that the second radio terminal has a target role in at least one sidelink positioning process, the at least one sidelink positioning process being designed to determine location information indicating the location of the second radio terminal having the target role, wherein at least one first radio terminal has an anchor role in at least one sidelink positioning process.
[0024] A favorable example is characterized in that the second radio terminal has an anchor role in at least one sidelink positioning process, wherein the at least one sidelink positioning process is designed to determine location information indicating the location of the first radio terminal having the target role.
[0025] An advantageous example is characterized in that the second radio terminal also performs the following actions: upon receiving a disconnect message, selecting a radio terminal with a target role in at least one sidelink positioning process as the server of at least one sidelink positioning process; and upon receiving a disconnect message, selecting or instructing selection rules such that at least one radio terminal with an anchor role in at least one sidelink positioning process becomes the corresponding slave device of at least one sidelink positioning process.
[0026] Advantageously, the role scheme of the sidelink positioning process can be used as a template for situations where the coverage area is out of range or partially out of range. No further radio communication or selection scheme is required to seamlessly continue the sidelink positioning process.
[0027] One aspect of the specification addresses the subject matter of a method for operating a second radio terminal, the method comprising: receiving, via at least one radio channel, a request from a location management function or from a first radio terminal indicating that a second radio terminal attached to a first radio access node is participating in at least one sidelink positioning process; initiating the at least one sidelink positioning process, wherein the at least one sidelink positioning process is initiated as a network-assisted sidelink positioning process; receiving, via a sidelink radio channel, a disengagement message indicating that the first radio terminal is disengaging from the first radio access node; and terminating the at least one sidelink positioning process having at least one first radio terminal as a participant in the sidelink positioning process.
[0028] One aspect of this specification relates to a location management device comprising: at least one processor; at least one memory including computer program code; and at least one radio communication module; wherein the at least one processor, the at least one memory, the at least one computer program code, and the at least one radio communication module cause the location management device to at least perform: receiving a status message from a second radio terminal via an uplink channel, the status message indicating that a first radio terminal has disconnected from a first radio access node associated with the location management device, and indicating the continuation of a sidelink positioning process.
[0029] Advantageously, the location management function knows the out-of-service status of the first radio terminal when it receives a status message.
[0030] A favorable example is characterized in that the location management device also performs: based on the reception of status messages, transmitting via a downlink channel at least one location message intended for at least one first radio terminal to a second radio terminal.
[0031] Advantageously, the location management function uses a second radio terminal as a relay to provide information to the first radio terminal.
[0032] One aspect of the specification addresses the subject matter of a method for operating a location management device, the method comprising: receiving a status message from a second radio terminal via an uplink channel, the status message indicating that a first radio terminal has disconnected from a first cell, particularly from a first radio access node associated with the location management device, and indicating the continuation of a sidelink positioning process.
[0033] According to another aspect of the present invention, a computer program is provided, comprising instructions to cause a first radio terminal or an embodiment thereof to perform the steps of the method or an embodiment thereof for operating a first radio terminal, and / or to cause a second radio terminal to perform the steps of the method or an embodiment thereof for operating a second radio terminal, and / or to cause a location management device to perform the steps of the method or an embodiment thereof for operating a location management device. Furthermore, a computer-readable medium having the above-described computer program stored thereon is provided.
[0034] One aspect of the specification addresses the use of one of the methods. Attached Figure Description
[0035] Figure 1 , 3 Figures 5 and 6 each depict examples of methods for operating a radio communication network in schematic sequence diagrams; Figure 2 , 4 Each of the six depicts Figure 1 , 3 Real-world examples of the methods in section 5; and Figure 7 The schematic diagram depicts a location management device and two radio terminals. Detailed Implementation
[0036] Figure 1 A schematic sequence diagram is described. The location management device LMF#1, implementing the location management function (LMF), sends 302 requests R#1 and R#2, instructing the first and second radio terminals UE#1 and UE#2, attached to the first radio cell, and particularly attached to the first radio access node gNB#1, to participate in at least one sidelink positioning procedure (SLP). The sidelink positioning procedure involves the location management function LMF, which is deployed in the backhaul network along with the device LMF#1.
[0037] Both the first and second devices receive requests R#1 and R#2 from the location management device LMF#1 or alternatively from another second radio terminal via at least a radio channel, particularly via a downlink channel.
[0038] Upon receiving the corresponding requests R#1 and R#2, the corresponding radio terminals UE#1 and UR#2 initiate at least one sidelink localization procedure (SLP) 104 and 204. Because the location management function (LMF) is involved, at least one sidelink localization procedure (SLP) is initiated as a network-assisted sidelink localization procedure.
[0039] At least one of UE#1 and UE#2 disconnects from the first radio cell, particularly from the first radio access node gNB#1 associated with the location management function (LMF), during the sidelink positioning procedure (SLP) at points 106 and 206. The disconnection occurs upon receiving or activating a handover trigger, which indicates a handover from the first radio cell, particularly from the first radio access node gNB#1, to the second radio cell, particularly to the second radio access node gNB#2. At least one of UE#1 and UE#2 terminates at least one sidelink positioning procedure (SLP) at points 116 and 216. This termination may involve determining the location of the corresponding radio terminal having a target role in the SLP. The termination may also involve SLP failure due to sidelink channel degradation.
[0040] After termination, UE#1, UE#2 synchronize with the second radio cell, particularly the second radio access node gNB#2 associated with the second location management function (LMF), and the associated second location management device (LMF#2) 120, 220. Synchronization occurs when at least one sidelink positioning procedure (SLP) terminates.
[0041] The first and second radio access nodes each provide a first or second radio cell, a first or second radio area, or a first or second radio beam. Therefore, the terms "radio cell," "radio area," and "radio beam" are used interchangeably in this specification.
[0042] The term "attached" used in the context of a radio terminal to a radio access node should be understood throughout the description as meaning that the radio terminal is in RRC_CONNECTED (RRC_connected) mode relative to the corresponding radio access node.
[0043] During conditional handover, UE#1 and UE#2 disconnect from source gNB#1 and apply the stored configuration for the selected candidate second cell while synchronizing with another second cell. According to this description, synchronization with the candidate second cell is maintained until SLP terminates. After SLP terminates, UE#1 and UE#2 complete the RRC handover process by sending an RRCReconfigurationComplete message to the target gNB#2. After successfully completing the RRC handover process, UE#1 and UE#2 release the stored CHO configuration.
[0044] The role of the target UE involves determining its location or position during the relevant sidelink localization process. The role of the anchor UE involves determining its location or position using measurements initiated and performed by the anchor UE.
[0045] The Sidelink Location Process (SLP) involves the Nlmf_Location service, which enables a Network Function (NF) to request location determination (current geodetic location and optional local and / or city location) for a target UE, or to request periodic or triggered location for the target UE. The service operations defined for Nlmf_Location are as follows: Determine Location: It provides the UE location information to the consumer NF; EventNotify: It notifies the consumer NF of the event of periodic or triggered location for the target UE; CancelLocation: It enables the consumer NF to cancel an ongoing periodic or triggered location for the target UE; and LocationContextTransfer: It enables the consumer NF to transfer the location context information of the periodic or triggered location for the target UE to a new Location Management Function (LMF). The "Retrieve UE Location" procedure allows the consumer NF to request the target UE's location information (geodetic location, and optional local and / or city location), or to activate periodic or triggered delayed location for the target UE.
[0046] The proposed solution forces the UE to be outside the coverage area of its LMF during the handover timer. Prior to this, an exception procedure for location was considered, using an exception out-of-coverage procedure. During the exception period, the server UE (e.g., the target UE) is responsible for the location process.
[0047] Figure 2 Depicting Figure 1 The example outlined in the document illustrates a process. This example focuses on a road scenario where determining the location of the target UE is crucial for road safety applications. Therefore, UEs #1-3 are described as road vehicles, specifically automobiles.
[0048] By definition, a UE outside the coverage area can be a UE not registered to the network or a temporarily unreachable UE. It may be in a known area, such as a factory or campus, or it may not be in a known area, and the application server may want to know its exact location via the network or other servers(s). When a UE is outside the coverage area, direct location on the Uu is impossible, and communication between the UE and the 5GC / LMF is also impossible. In direct communication between the LMF and the UE, it can be assumed that the UE is outside the coverage area via another UE (via a sidelink) or a non-3GPP connection. Due to network-assisted sidelink location and / or server-UE-assisted location and / or direct ranging between two UEs (requiring ranging / sidelink location between the target UE and the anchor UE), the two UEs must be close to each other within an effective range (e.g., a communication range or an effective location range). The nodes involved are included in the sidelink location process, preferably a session-based location process.
[0049] Innovative variants: according to Figure 2 In the example shown, all UEs #1-3 are switched out of coverage. In state 2#1, all UEs #1-3 are in RRC_CONNECTED mode relative to the first cell.
[0050] According to state 2#2, during coverage of at least one cell (cell 1), handover HO and handover condition CH involving UE#1-3 are detected during the requested SL positioning process. This will affect at least the SLPP positioning process for network-assisted SL positioning.
[0051] Switching conditions can be triggered in the following ways: RSSI measurement, RSRP measurement, location-based conditions, time-based conditions, internal measurement procedures (e.g., using radio link failure (RLF) measurements and RLF timers), etc.
[0052] According to State 2#2: The involved UEs UE #1-3 are outside the coverage area of LMF #1, and a UE (e.g., the target UE) will become the server UE and be responsible for the process until the SL positioning process ends. The involved UEs UE #1-3 leave the coverage area for the same SLPP SL positioning request and any further related requests belonging to the same SLPP SL positioning request during the duration of the HO.
[0053] According to state 2#3, UE or radio terminal UE#1-3 continues SLP outside coverage (handled by server UE#1 and disconnected from LMF#1). As long as the SLP request process is ongoing / resuming / not completed, SLPP will continue the status quo (outside coverage) for all UEs involved in the previous / completed HO.
[0054] In other words, the only temporary handover of the corresponding radio terminal (such as UE#1-3) to outside the coverage area is maintained before connecting to another cell or other radio access node.
[0055] According to state 2#4, at the end of the abnormal process, the involved UEs UE #1-3 are now in a new cell (e.g., cell 2) and connected to the same (and new) LMF (e.g., LMF#2). Therefore, SLPP can trigger a new request for coverage, and SLPP can pass messages to / from LMF2.
[0056] Figure 3 A schematic sequence diagram is depicted. (With) Figure 1 on the contrary, Figure 3The method described involves UE#1, as the target UE, disengaging from a first cell, while UE#2, as the anchor UE, remains at least partially within the coverage area of the first cell.
[0057] After or before sending 108 Disengagement Message D#1 via the sidelink radio channel, UE#1 selects 162 a radio terminal with target role T participating in the sidelink location procedure SLP as the server of at least one sidelink location procedure SLP, and UE#1 selects 164 at least one radio terminal with anchor role A in the sidelink location procedure SLP as the corresponding slave device of at least one sidelink location procedure SLP.
[0058] The disconnect message D#1 instructs the first radio terminal UE#1 to disconnect from the first cell, and in particular from the first radio access node gNB#1.
[0059] After receiving the 208 disconnect message D#1 via the sidelink radio channel, UE#2 selects 262, a radio terminal with target role T participating in the sidelink location procedure SLP, as the server of at least one remaining sidelink location procedure SLP, and UE#2 selects 264, at least one radio terminal with anchor role A in the sidelink location procedure SLP, as the corresponding slave device of at least one remaining sidelink location procedure SLP.
[0060] Since UE#2 is still in RRC_CONNECTED mode relative to gNB#1, UE#2 sends a 210 status message S#2 via the uplink channel. The status message S#2 indicates that at least the first radio terminal UE#1 has been disconnected from the first cell, in particular from the first radio access node gNB#1, and indicates that the sidelink positioning procedure SLP will continue together with the disconnected radio terminal UE#1.
[0061] RRC_CONNECTED mode is part of the Radio Resource Control (RRC) protocol in cellular networks, such as 5G networks with gNBs (next-generation NodeBs). It represents a specific state within a User Equipment (UE), such as a smartphone or tablet. If the UE is in RRC_CONNECTED mode, the corresponding gNB has already allocated specific radio resources to the UE, allowing it to communicate directly with the gNB. Because resources have been allocated, communication can occur with lower latency, resulting in faster response times. The network actively tracks the UE's location to ensure optimized data routing and seamless handover between cells when the UE moves.
[0062] Conversely, when the UE is in RRC_IDLE (RRC_Idle) mode, the network does not know its exact location and does not allocate dedicated resources. This reduces energy consumption on the UE, but also leads to higher latency when switching back to RRC_CONNECTED mode.
[0063] The RRC_CONNECTED mode is crucial for providing location management services, where low latency and continuous connectivity are important.
[0064] In RRC_CONNECTED, the UE performs NR sidelink communication and / or V2X sidelink communication as configured by the upper layer. The UE sends sidelink UE information to the NG-RAN to request or release sidelink resources and report QoS information for each destination.
[0065] NG-RAN provides RRCReconfiguration to the UE to offer dedicated sidelink configurations. RRCReconfiguration may include one or more SL DRB configurations for NR sidelink communication, as well as Mode 1 and / or Mode 2 resource configurations. If the UE has already received an SL DRB configuration via system information, the UE should continue to use that configuration for sidelink data transmission and reception until it receives a new configuration via RRCReconfiguration.
[0066] NG-RAN can also configure the measurement and reporting of CBR for NR sidelink communication and V2X sidelink communication, as well as report the location information of V2X sidelink communication to the UE via RRCReconfiguration. During handover, the UE performs sidelink transmission and reception based on the exception transmission resource pool of the target cell provided in the handover command or the configured sidelink grant type 1 and receive resource pool.
[0067] After receiving the 310 status message S#1, LMF#1 sends at least one 212 location message P via the downlink channel, the location message P being intended for at least one first radio terminal UE#1 in out-of-mode.
[0068] After receiving at least one location message P in 212, UE#2 sends at least one location message P in 214 to at least one first radio terminal UE#1 that has left the first cell via a side link channel.
[0069] After terminating the 116 and 216 side link positioning process (SLP), UE#1 synchronizes with the second cell, especially with gNB#2, and enters the RRC_CONNECTED mode relative to the second cell, while UE#2 remains in the RRC_CONNECTED mode relative to the first cell.
[0070] Figure 4 Depicting Figure 3 Example of the process outlined in [the document]. According to state 4#1, the involved UEs UE #1-3 are within the coverage area of cell 1, where each triggered SLP can be processed as being within coverage area if requested. SLPP begins with network-assisted positioning under LMF control. Here, all measurements and final location calculations should be performed in the LMF and transmitted to the requesting, initiating, and / or terminating terminal via the LMF and SLPP protocols.
[0071] According to state 4#2, target UE#1 initiates / triggers its HO condition in cell 1 based on the aforementioned HO condition. Therefore, the target UE begins to lose its connection with cell 1 and / or LMF#1, which was under control during the initiation of the SLPP SL location request.
[0072] The target UE initiates / triggers its HO condition in cell 1, beginning to lose connection with cell 1 and / or LMF#1. As a result, the target UE (or any other anchor UE) triggers an anomalous handover with partial coverage conditions, i.e., allowing the SLP to remain under the control of LMF#1 (e.g., by any anchor UE connected to LMF#1), or by triggering a loss of coverage conditions (e.g., by selecting a server UE).
[0073] Based on the partial coverage SLPP, target UE#1 triggers an abnormal SL location handover state, declaring partial coverage conditions such that the target UE is outside the coverage area of cell 1 and LMF 1. The HO trigger will be transmitted to one or all anchor UEs linked to the target UE. After the triggered handover, the anchor UE or all anchor UEs send an "SLPP Control Update Request" (SLPP-CUP-REQ) to the LMF (initiating SLPP), notifying the LMF that the target UE is not within coverage for the remainder of the SLPP procedure associated with the existing request. As long as one or more anchor UEs are within the coverage area of the cell / LMF-initiated SLPP request, the SLP procedure and all SLPP messages remain controlled by the same LMF, LMF#1. SLPP messages will be transmitted to the target UE (if needed) through any anchor UE (e.g., connected to LMF#1).
[0074] According to the SLPP for leaving coverage, when the target UE#1 triggers the HO condition, the SLPP for leaving coverage can be requested from the target UE to its anchor UE, and for example, after the target UE selects itself as the server UE. The target UE can continue to control the SLPP protocol (as the server UE) until the SLP procedure for the given request is completed / ended. The anchor UE (any or all of them within coverage) will send an SLPP handover termination request (SLPP Request for Termination (SLPP-REQ-Termination)) to LMF#1, that is, notify LMF#1 that the target UE will continue the request as the server UE.
[0075] According to state 4#3, the target UE continues to perform the initially requested SLPP (until it ends), either outside the coverage area (according to variant 2, step 2, option 2, where the SLP is controlled by the server UE / target UE) or within the coverage area (the SLP is controlled by the LMF, which initiates the SLPP request via any connection to the anchor).
[0076] Figure 5 A schematic sequence diagram is depicted. (With) Figure 1 on the contrary, Figure 5 The method described involves UE#2, acting as the anchor UE, disengaging from the first cell, while UE#1, acting as the target UE, remains at least partially within the coverage area of the first cell.
[0077] After the start of SLP 204, during the side link positioning procedure SLP, at the time of reception or activation (not shown) triggered by the handover, UE#2 disconnects from the first radio cell, in particular from the first radio access node gNB#1 associated with the location management function LMF 206, wherein the handover trigger indicates a handover from the first radio cell, in particular from the first radio access node gNB#1 to the second radio cell, in particular to the second radio access node gNB#2.
[0078] UE#2 sends a 208 disconnect message D#2 via the sidelink radio channel, indicating that UE#2 is disconnecting from the first cell, in particular from the first radio access node gNB#1.
[0079] After receiving 108 D#2, UE#1 sends a 110 status message S#1 via the uplink channel. The status message S#1 indicates that UE#2 has disengaged from the first cell, in particular from the first radio access node gNB#1, and indicates the continuation of the sidelink location procedure SLP involving UE#2 in the uncovered disengagement mode.
[0080] Based on the receipt of D#2, UE#1 selects 162, a radio terminal having a target role T in at least one sidelink positioning procedure (SLP), as the server for the remaining part of the at least one sidelink positioning procedure (SLP). Furthermore, UE#1 selects 164, at least one radio terminal having an anchor role A in at least one sidelink positioning procedure (SLP), as the corresponding slave device for the remaining part of the at least one sidelink positioning procedure (SLP).
[0081] After receiving at least one location message P destined for UE#2 via the downlink channel, UE#1 sends at least one location message P via the sidelink channel to at least one second radio terminal UE#2.
[0082] After terminating 216 SLP, UE#2 switches to the second cell by synchronizing with the second cell 220 and entering the RRC_CONNECTED mode relative to the second cell, while UE#1 remains in the RRC_CONNECTED mode relative to the first cell.
[0083] Figure 6 Depicting Figure 5 Example of the process outlined in [the document]. According to state 6#1, the involved UEs UE #1-3 are within the coverage area of cell 1, where each triggered SLP can be processed as being within coverage if requested according to state 6#2. Anchor UEs UE #2-3 leave the coverage area of cell 1, triggering the HO condition on UE #2-3. Target UE #1 (assisted by signaling on the SL between the anchor UE and itself) triggers a partial or out-of-coverage condition.
[0084] Depending on the partial coverage, LMF#1 maintains control over the SLP, and SLP measurements are transmitted to the anchor UE (via the target UE) via SL communication. The target UE#1 maintains the connection (and executes) the SLP low-level messages and receives the SLPP procedure from the initiating LMF#1. According to one example, the target UE#1 notifies LMF#1 of the partial coverage status (one or more anchor UEs are not within coverage) via an SLPP Control Update Request (SLPP-CUP-REQ).
[0085] Based on the out-of-coverage condition, the selected server UE (e.g., target UE or any anchor UE) and the SLPP message are generated / controlled by the selected server UE. Target UE #1 determines that it is out of coverage / receives the out-of-coverage decision from the anchor UE, and the target UE sends an SLPP termination request (SLPP-Termination-REQ) to its LMF (initiating LMF).
[0086] According to State 6#3, the anchor UE and the target UE continue the given (same) SLP request using the same update state (i.e., partial coverage (option 1) or out of coverage (option 2)) until the SLP ends / completes or the SL link terminates (e.g., the SL range exceeds the coverage limit or RSRP / RSSI deteriorates).
[0087] Figure 7 The schematic block diagram depicts a location management device LMF#1, first and second radio terminals UE#1 and UE#2, each including at least one processor P#1, P#2, P#3, at least one non-transitory memory M#1, M#2, M#3 including computer program code, and at least one radio communication module C#1, C#2, C#3 including a corresponding antenna.
Claims
1. The first radio terminal (UE#1, UE#2) includes: At least one processor; At least one memory containing computer program code; and at least one radio communication module; At least one processor, at least one memory, at least one computer program code, and at least one radio communication module enable the first radio terminal (UE#1, UE#2) to perform at least the following: Requests (R#1, R#2) are received via at least one radio channel from the location management device (LMF#1) or from the second radio terminal (UE#2, UE#1), the requests instructing the first radio terminal (UE#1, UE#2) attached to the first radio access node (gNB#1) to participate in at least one sidelink location procedure (SLP). Initiate (104, 204) the at least one side link localization process (SLP), wherein the at least one side link localization process (SLP) is initiated as a network-assisted side link localization process; During the sidelink positioning process (SLP), upon receiving and / or activating a handover trigger, the device disconnects from the first radio access node (gNB#1) associated with the location management function (LMF) (106, 206), wherein the handover trigger indicates a handover from the first radio access node (gNB#1) to the second radio access node (gNB#2). Terminate (116, 216) the at least one side link localization procedure (SLP); and When at least one side link positioning procedure (SLP) terminates, it is synchronized with the second radio access node (gNB#2) (120, 220).
2. The first radio terminal (UE#1, UE#2) according to claim 1, wherein the first radio terminal (UE#1, UE#2) further performs: A disconnect message (D#1, D#2) instructing the first radio terminal (UE#1, UE#2) to disconnect from the first radio access node (gNB#1) is transmitted via the side link radio channel (108, 208).
3. The first radio terminal (UE#1, UE#2) according to claim 1 or 2, wherein the first radio terminal (UE#1, UE#2) further performs: At least one location message (P) is received from a second radio terminal (UE#2, UE#1) via a sidelink channel (114, 214), wherein the at least one location message (P) originates from a location management device (LMF#1).
4. A first radio terminal (UE#1, UE#2) according to any one of the preceding claims, wherein the first radio terminal (UE#1, UE#2) has a target role (T) in the at least one sidelink positioning process (SLP), wherein the at least one sidelink positioning process (SLP) is designed to determine location information indicating the location of the first radio terminal (UE#1, UE#2) having a target role (T), wherein a second radio terminal or the at least one second radio terminal (UE#2, UE#1) has an anchor role (A) in the at least one sidelink positioning process (SLP).
5. The first radio terminal (UE#1, UE#2) according to any one of claims 1 to 3, wherein the first radio terminal (UE#1, UE#2) has an anchor role (A) in the at least one side link positioning process (SLP), wherein the at least one side link positioning process (SLP) is designed to determine location information indicating the location of a second radio terminal (UE#2, UE#1) having a target role (T).
6. The first radio terminal (UE#1, UE#2) according to any one of claims 4 or 5, wherein the first radio terminal (UE#1, UE#2) further performs: Upon disconnection from the first radio access node (gNB#1), radio terminals with a target role (T) participating in the Side Link Localization Process (SLP) are selected (162, 262) to become servers of at least one Side Link Localization Process (SLP); and When disconnecting from the first radio access node (gNB#1), at least one radio terminal (164, 264) that has an anchor role (A) in the side link positioning process (SLP) is selected as the corresponding slave device of at least one side link positioning process (SLP).
7. A method for operating a first radio terminal (UE#1, UE#2), the method comprising: Requests (R#1, R#2) are received (102, 202) from the location management device (LMF#1) or from the second radio terminal (UE#2, UE#1) via at least a radio channel, the requests instructing the first radio terminal (UE#1, UE#2) attached to the first radio access node (gNB#1) to participate in at least one sidelink location procedure (SLP). Initiate (104, 204) the at least one side link localization process (SLP), wherein the at least one side link localization process (SLP) is initiated as a network-assisted side link localization process; During the sidelink positioning process (SLP), upon receiving or activating a handover trigger, the device disconnects from the first radio access node (gNB#1) associated with the location management function (LMF) (106, 206), where the handover trigger indicates a handover from the first radio access node (gNB#1) to the second radio access node (gNB#2). Termination (116) of at least one sidelink localization procedure (SLP); and When at least one side link positioning procedure (SLP) terminates, the second radio access node (gNB#2) is synchronized (120).
8. A second radio terminal (UE#2, UE#1), comprising: At least one processor; At least one memory containing computer program code; and at least one radio communication module; At least one processor, at least one memory, at least one computer program code, and at least one radio communication module enable the second radio terminal (UE#1, UE#2) to perform at least the following: A request (202, 102) is received via at least one radio channel from the location management function (LMF#1) or from the first radio terminal (UE#1), the request indicating that a second radio terminal (UE#2) attached to the first radio access node (gNB#1) is participating in at least one sidelink location process (SLP). Initiate (204, 104) the at least one side link localization procedure (SLP), wherein the at least one side link localization procedure (SLP) is initiated as a network-assisted side link localization procedure; Receive, via sidelink radio channel (208, 108), a disconnection message (D#2, D#1) instructing the first radio terminal (UE#1) to disconnect from the first radio access node (gNB#1); and Terminate (216, 116) at least one side link localization process (SLP) having the at least one first radio terminal (UE#1) as a participant in the side link localization process (SLP).
9. The second radio terminal (UE#2, UE#1) according to claim 8, wherein the second radio terminal (UE#2, UE#1) further performs: Status messages (S#2, S#1) are sent via the uplink channel (210, 110), indicating that the first radio terminal (UE#1, UE#2) has disconnected from the first radio access node (gNB#1) and indicating the continuation of the sidelink positioning procedure (SLP).
10. The second radio terminal (UE#2, UE#1) according to claim 8 or 9, wherein the second radio terminal (UE#2, UE#1) further performs: Receive at least one location message (P) intended for the at least one first radio terminal (UE#1, UE#2) via downlink channel (212, 112); and At least one location message (P) is sent (214, 114) to at least one first radio terminal (UE#1, UE#2) via a side link channel.
11. The second radio terminal (UE#2, UE#1) according to any one of claims 8 to 10, wherein the second radio terminal (UE#1, UE#2) has a target role in the at least one sidelink positioning process (SLP), wherein the at least one sidelink positioning process (SLP) is designed to determine location information indicating the location of the second radio terminal (UE#2, UE#1) having the target role, and wherein the at least one first radio terminal (UE#1, UE#2) has an anchor role in the at least one sidelink positioning process (SLP).
12. The second radio terminal (UE#2, UE#1) according to any one of claims 8 to 10, wherein the second radio terminal (UE#2, UE#1) has an anchor role in the at least one side link positioning process (SLP), wherein the at least one side link positioning process (SLP) is designed to determine location information indicating the location of the first radio terminal (UE#1, UE#2) having a target role.
13. The second radio terminal (UE#2, UE#1) according to any one of claims 11 or 12, wherein the second radio terminal (UE#2, UE#1) further performs: Upon receiving the disconnect message (D#2, D#1), select (262, 162) the radio terminal that has the target role (T) in at least one side link localization procedure (SLP) as the server of at least one side link localization procedure (SLP); and Upon receiving a disconnect message (D#2, D#1), at least one radio terminal (264, 164) that has an anchor role (A) in at least one side link positioning procedure (SLP) is selected as the corresponding slave device of at least one side link positioning procedure (SLP).
14. A method for operating a second radio terminal (UE#2, UE#1), the method comprising: Receive (202, 102) requests (R#2, R#1) from the location management function (LMF#1) or from the first radio terminal (UE#1) via at least one radio channel, the requests indicating that a second radio terminal (UE#2) attached to the first radio access node (gNB#1) is participating in at least one sidelink location process (SLP). Initiate (204, 104) the at least one side link localization procedure (SLP), wherein the at least one side link localization procedure (SLP) is initiated as a network-assisted side link localization procedure; Receive, via sidelink radio channel (208, 108), a disconnection message (D#2, D#1) instructing the first radio terminal (UE#1) to disconnect from the first radio access node (gNB#1); and Termination of at least one sidelink localization process (SLP) with at least one first radio terminal (UE#1) as a participant in the sidelink localization process (SLP) (216, 116).
15. A location management device (LMF#1), comprising: At least one processor; At least one memory containing computer program code; and at least one radio communication module; At least one processor, at least one memory, at least one computer program code, and at least one radio communication module enable the location management device (LMF#1) to perform at least the following: A status message (S#2, S#1) is received from the second radio terminal (UE#2, UE#1) via the uplink channel. The status message indicates that the first radio terminal (UE#1, UE#2) has disconnected from the first radio access node (gNB#1) associated with the location management device (LMF#1) and indicates the continuation of the sidelink positioning procedure (SLP).
16. The location management device (LMF#1) according to claim 15, wherein the location management device (LMF#1) further performs: Based on the receipt of status messages (S#2, S#1), at least one location message (P) intended to be sent to at least one first radio terminal (UE#1, UE#2) via a downlink channel to the second radio terminal (UE#2, UE#1).
17. A method for operating a position management device (LMF#1), the method comprising: A status message (S#2, S#1) is received from the second radio terminal (UE#2, UE#1) via the uplink channel. The status message indicates that the first radio terminal (UE#1, UE#2) has disconnected from the first radio access node (gNB#1) associated with the location management device (LMF#1) and indicates the continuation of the sidelink positioning procedure (SLP).