CN113950110A

CN113950110A - Method and device for switching Uu path to direct communication path and indicating candidate relay UE, storage medium, terminal and base station

Info

Publication number: CN113950110A
Application number: CN202010687605.8A
Authority: CN
Inventors: 曹春燕; 刘星
Original assignee: Spreadtrum Semiconductor Nanjing Co Ltd
Current assignee: Spreadtrum Semiconductor Nanjing Co Ltd
Priority date: 2020-07-16
Filing date: 2020-07-16
Publication date: 2022-01-18
Anticipated expiration: 2040-07-16
Also published as: CN113950110B; WO2022012426A1

Abstract

A method, a device, a storage medium, a terminal and a base station for switching a Uu path to a direct communication path and indicating candidate relay UE (user equipment), wherein the method for switching the Uu path to the direct communication path comprises the following steps: sending a first message, wherein the first message comprises position information of an edge UE; receiving a second message, wherein the second message comprises an identification of one or more candidate relay UEs determined from the location information of the edge UE; selecting a preferred relay UE from the one or more candidate relay UEs, and establishing a direct communication path with the preferred relay UE. The scheme of the invention can greatly reduce the time delay of path conversion.

Description

Method and device for switching Uu path to direct communication path and indicating candidate relay UE, storage medium, terminal and base station

Technical Field

The invention relates to the technical field of communication, in particular to a method, a device, a storage medium, a terminal and a base station for switching a Uu path to a direct communication path and indicating candidate relay UE.

Background

In the protocol version 12(Release 12, abbreviated as R12), a Proximity-based Services (ProSe) direct communication mode is introduced in Long Term Evolution (LTE). User Equipment (UE for short) a and UE B (may be multiple UEs) may communicate directly through a PC5 interface, where the PC5 interface is a direct interface between UEs. The communication interface between the UE and the base station is called Uu interface (where U denotes User to Network interface; U denotes Universal).

In a System and business aspect (SA) Working Group (WG) 2 of the third Generation Partnership Project (3rd Generation Partnership Project, 3GPP) to study a System architecture of ProSe direct communication, a communication architecture in which a UE is connected to a network (UE-to-network Relay) through a Relay is introduced. The communication architecture enables a UE (e.g., UE a) that cannot directly communicate with a base station to relay service data through another UE (e.g., UE B) to implement direct communication, where UE B is a relay UE (relay UE).

The 3GPP also introduced a communication architecture in which the UE connects to the UE (UE-to-UE Relay) through a Relay. The communication architecture enables UE a and UE B, which cannot directly communicate through the PC5 link, to relay traffic data through other UEs (i.e., relay UEs) to enable direct communication.

A UE communicating through a relay UE is generally called an edge user (Remote UE, hereinafter referred to as edge UE). Regardless of the communication architecture in which the UE is connected to the network through the relay or the UE is connected to the UE through the relay, the edge UE that wants to communicate through the relay UE needs to perform a handover of the Uu path to the PC5 path.

According to the prior art, in the process of performing the Uu path switching to the PC5 path, the edge UE needs to first perform a Relay discovery (Relay discovery) process to discover candidate Relay UEs available around. Then, the Reference Signal Receiving Power (RSRP) between the candidate relay UE and the candidate relay UE is measured. Then, the edge UE reports the measurement result to the base station, and the base station makes a path switching judgment and selects an optimal relay UE. And the edge UE is switched to the relay UE from the source base station, so that the conversion from the Uu path to the PC5 path is completed.

The delay of the aforementioned whole path switching is very large. Specifically, the edge UE needs to perform measurement and measurement reporting, which is time-consuming in the whole process. And the time delay from the decision of the base station to the down-sending of the switching result to the execution of the path switching by the UE is also relatively large. Moreover, the signaling overhead of the edge UE to perform the relay discovery process is also relatively large.

Disclosure of Invention

The invention solves the technical problem of reducing the time delay of path conversion from a Uu path to a direct communication path.

To solve the foregoing technical problem, an embodiment of the present invention provides a method for switching a Uu path to a direct communication path, including: sending a first message, wherein the first message comprises position information of an edge UE; receiving a second message, wherein the second message comprises an identification of one or more candidate relay UEs determined from the location information of the edge UE; selecting a preferred relay UE from the one or more candidate relay UEs, and establishing a direct communication path with the preferred relay UE.

Optionally, the second message further includes a link quality threshold for relay selection.

Optionally, the operation of sending the first message is performed in response to the link quality of the Uu path being lower than a first preset threshold.

Optionally, the first message further includes link quality of the Uu path.

Optionally, the selecting a preferred relay UE from the one or more candidate relay UEs includes: broadcasting a direct communication request, wherein the direct communication request includes an identification of the one or more candidate relay UEs; determining the preferred relay UE based on the responses of the one or more candidate relay UEs.

Optionally, the selecting a preferred relay UE from the one or more candidate relay UEs includes: unicast a direct communication request to the one or more candidate UEs, respectively; determining the preferred relay UE based on the responses of the one or more candidate relay UEs.

Optionally, the determining the preferred relay UE according to the response of the one or more candidate relay UEs includes: when only the response message of a single candidate relay UE is received, measuring the link quality between the candidate relay UE and the response, and determining the candidate relay UE of the response as the preferred relay UE according to the measurement result; and when response messages of a plurality of candidate relay UEs are received, determining the preferred relay UE according to the link quality between the preferred relay UE and each candidate relay UE responding.

Optionally, the direct communication request includes a quality of service indicator for establishing the direct communication path.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a method for indicating candidate relay UEs, including: receiving a first message, wherein the first message comprises location information of an edge UE; selecting one or more candidate relay UEs from a preset available relay UE list according to the position information of the edge UE; and generating and transmitting a second message based on the one or more candidate relay UEs.

Optionally, the first message is sent when determining that the link quality of the Uu path is lower than a first preset threshold, where the Uu path is a communication link between the edge UE and the base station.

Optionally, the first message further includes link quality of the Uu path.

Optionally, the candidate relay UE indication method further includes: receiving capability report information; and determining whether to add the UE sending the capability reporting information to the preset available relay UE list or to delete the UE sending the capability reporting information from the preset available relay UE list according to the capability reporting information.

Optionally, the preset available relay UE list includes location information of each candidate relay UE.

Optionally, the preset available relay UE list includes relay UEs of neighboring base stations.

Optionally, the preset available relay UE list is updated in real time.

Optionally, the selecting one or more candidate relay UEs from a preset available relay UE list according to the location information of the edge UE includes: and determining the relay UE which is positioned in a preset radius range by taking the position of the edge UE as the center of a circle in the preset available relay UE list as the one or more candidate relay UEs.

Optionally, the preset radius is associated with at least the location information of the edge UE, the transmission power of the relay UE, and/or the transmission power of the edge UE.

To solve the foregoing technical problem, an embodiment of the present invention further provides a device for switching a Uu path to a direct communication path, including: a sending module, configured to send a first message, where the first message includes location information of an edge UE; a receiving module, configured to receive a second message, wherein the second message includes an identification of one or more candidate relay UEs, and the one or more candidate relay UEs are determined according to the location information of the edge UE; a switching module, configured to select a preferred relay UE from the one or more candidate relay UEs, and establish a direct communication path with the preferred relay UE.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a candidate relay UE indicating apparatus, including: a receiving module, configured to receive a first message, where the first message includes location information of an edge UE; a selection module, configured to select one or more candidate relay UEs from a preset available relay UE list according to the location information of the edge UE; an indication module configured to generate and transmit a second message based on the one or more candidate relay UEs.

To solve the above technical problem, an embodiment of the present invention further provides a storage medium, on which a computer program is stored, and the computer program executes the steps of the above method when being executed by a processor.

In order to solve the above technical problem, an embodiment of the present invention further provides a terminal, including a memory and a processor, where the memory stores a computer program capable of running on the processor, and the processor executes the steps of the method when running the computer program.

In order to solve the above technical problem, an embodiment of the present invention further provides a base station, including a memory and a processor, where the memory stores a computer program capable of running on the processor, and the processor executes the steps of the method when running the computer program.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:

for an edge UE side, an embodiment of the present invention provides a method for switching a Uu path to a direct communication path, including: sending a first message, wherein the first message comprises position information of an edge UE; receiving a second message, wherein the second message comprises an identification of one or more candidate relay UEs determined from the location information of the edge UE; selecting a preferred relay UE from the one or more candidate relay UEs, and establishing a direct communication path with the preferred relay UE.

The embodiment provides a more effective method for converting a Uu path into a direct communication path, and can greatly reduce the time delay of path conversion. Specifically, the first message sent by the edge UE does not carry the link quality measurement result with the surrounding candidate relay UEs, but reports its own position. Correspondingly, the candidate relay UEs available around the edge UE are directly indicated in the second message sent by the base station for the edge UE to select. Because the edge UE does not need to execute the relay discovery process, the time delay of the three steps of measurement, measurement report and base station decision can be saved. Further, signaling overhead during path switching can be greatly reduced.

For the base station side, an embodiment of the present invention further provides a candidate relay UE indication method, including: receiving a first message, wherein the first message comprises location information of an edge UE; selecting one or more candidate relay UEs from a preset available relay UE list according to the position information of the edge UE; and generating and transmitting a second message based on the one or more candidate relay UEs.

The embodiment provides a more efficient indication method for candidate relay UE, which can greatly reduce signaling overhead during path switching. Specifically, the base station maintains a preset available relay UE list, and selects a suitable candidate relay UE from the list to indicate to the edge UE after receiving the first message. It is not necessary for the base station to receive the link quality with each candidate relay UE measured by the edge UE, making it possible to reduce signaling overhead. Furthermore, the base station does not need to make a decision according to the link quality measurement result, so that the time delay can be reduced.

Drawings

Fig. 1 is a flowchart of a method for switching a Uu path to a direct communication path according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a device for switching a Uu path to a direct communication path according to an embodiment of the present invention;

fig. 3 is a flowchart of a method for indicating candidate relay UEs according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a candidate relay UE indication apparatus according to an embodiment of the present invention.

Detailed Description

As mentioned in the background, the existing path switching (also referred to as handover) procedure for performing the Uu path to the PC5 path has a very large delay. The signaling overhead is also large.

Specifically, the existing edge UE performs path switching from the Uu path to the PC5 path by first performing a relay discovery procedure, which aims at the edge UE discovering surrounding relay UEs.

Relay discovery includes two modes: mode A (model A) and mode B (model B). The principle of the mode A is as follows: each relay UE periodically broadcasts relay discovery information, and peripheral edge UEs needing relay service can discover whether relay UEs exist nearby only by monitoring the broadcast information. The principle of mode B is: the edge UE transmits a Solicitation message (Solicitation message) to the surrounding relay UEs, and the relay UEs reply a Response message (Response message) to the edge UE after receiving the Solicitation message.

In a communication architecture in which a UE is connected to a network through a relay, an edge UE switches from a Uu path to a PC5 path, and there are two scenarios in the current protocol: 1. the edge UE and the relay UE are positioned under the same base station, namely the conversion from the Uu path to the PC5 path in the same cell; 2. the edge UE and the relay UE are under different base stations, i.e. the Uu path to PC5 path switching between cells.

In any scenario, the prior art performs the Uu path to PC5 path conversion process steps as follows:

step 1: the edge UE initially establishes a connection with the base station and transmits data traffic over the Uu interface. When the signal quality between the edge UE and the base station is deteriorated, the base station configures the edge UE to perform the conversion measurement from the Uu path to the PC5 path through the proprietary signaling.

Step 2: after receiving the measurement configuration signaling of the base station, the edge UE performs a relay discovery process to discover candidate relay UEs available around and measure RSRP between the edge UE and the candidate relay UEs.

And step 3: and reporting the measurement result to the base station by the edge UE, wherein the reported content comprises the discovered candidate relay UE and the RSRP value between the candidate relay UE and the candidate relay UE.

And 4, step 4: after receiving the measurement result reported by the edge UE, the base station makes a path switching decision according to the measurement result to select an optimal relay UE, and then informs the edge UE to execute path switching.

And 5: (1) if the relay UE selected by the base station and the edge UE are in the same cell, the edge UE directly initiates a connection establishment process with the relay UE to complete the conversion from the Uu path to the PC5 path; (2) if the relay UE selected by the base station and the edge UE are in different cells, a source base station where the edge UE is located firstly carries out a switching request process with a target base station where the relay UE is located; the target base station inquires about the relay UE, and if the relay UE confirms the switching request, the target base station sends a switching confirmation message to the source base station; after receiving the switching confirmation, the source base station informs the edge UE through a reconfiguration signaling, and the edge UE reestablishes the connection with the relay UE. At this point, the conversion of the Uu path to the PC5 path is completed.

On the other hand, the process of establishing connection between the edge UE and the relay UE may include four steps:

step 1: the edge UE sends a direct communication request message to initiate the PC5 unicast link establishment procedure. The direct communication request message may include: 1) source User information (source User Info), such as an application layer Identification (Identification, abbreviated as ID) of the initial UE, that is, an application layer ID of the edge UE; 2) a vehicle to outside information exchange (V2X for short) service identifier; 3) target User information (target User Info), such as an application layer ID of the target UE, i.e. an application layer ID of the relay UE; 4) and safely establishing information.

Step 2: after receiving the direct communication request message, the relay UE sends a direct security mode control message to the edge UE to confirm whether a security context exists with the edge UE, if not, a new security context is established, and a security related process with the relay UE is established.

And step 3: and the edge UE replies a direct security mode completion message to the relay UE.

And 4, step 4: after the relay UE receives the direct security mode, the relay UE sends a direct communication acceptance message to the edge UE, which represents acceptance of the PC5 unicast link establishment procedure. Wherein, the direct communication request acceptance message may include: 1) source User information (source User Info), such as an application layer ID of the target UE, i.e., an application layer ID of the relay UE; 2) corresponding Quality of Service (QoS) parameters of PC 5; 3) internet Protocol (IP) address configuration, etc.

The 5 steps of the prior art for executing the Uu path to PC5 path conversion process are very tedious, and the time delay of the whole path conversion is large. Especially, the delay from the edge UE to the UE to perform the path switching is long, and the signaling overhead for performing the relay discovery process is large.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 1 is a flowchart of a method for switching a Uu path to a direct communication path according to an embodiment of the present invention.

The present embodiment may be performed by the user equipment side, such as by an edge UE. By performing the scheme of the embodiment shown in fig. 1, the edge UE can switch from the Uu path to the direct communication path. The direct communication path may be a PC5 path, or may be another communication path that enables direct communication with another UE (e.g., a relay UE).

Specifically, referring to fig. 1, the method for switching the Uu path to the direct communication path according to this embodiment may include the following steps:

step S101, sending a first message, wherein the first message comprises the position information of the edge UE;

step S102, receiving a second message, wherein the second message includes an identifier of one or more candidate relay UEs, and the one or more candidate relay UEs are determined according to the position information of the edge UE;

step S103, selecting a preferred relay UE from the one or more candidate relay UEs, and establishing a direct communication path with the preferred relay UE.

In one implementation, when the signal quality between the edge UE and the base station is poor and the relay UE is needed to relay the traffic to the base station, the edge UE may execute step S101 to send a first message to the base station, thereby triggering the base station to perform path switching.

For example, the base station may configure a measurement report trigger event for the edge UE in advance to trigger the edge UE to execute step S101. The measurement reporting trigger event may be that the link quality between the edge UE and the base station is lower than a first preset threshold. The first preset threshold may be pre-configured by the base station to the edge UE.

The link quality between the edge UE and the base station may be characterized based on RSRP.

In one implementation, the first message may include location information of the edge UE itself that sent the message, such as a Zone Identification (Zone _ Identification, abbreviated as Zone _ ID). For another example, the location information of the edge UE may be location information determined based on a Global Positioning System (GPS) of the edge UE.

In one implementation, the first message may include link quality of the Uu path in addition to the location of the edge UE itself, so that the base station further knows the actual link condition with the edge UE. For example, the first message may include an actual RSRP value measured by the edge UE with the base station.

Accordingly, the first message may be understood as a measurement result message, which is used to report a measurement result of the link quality of the Uu path.

In one implementation, in response to receiving the first message, the base station may send a second message to the edge UE to instruct the edge UE to perform path switching.

Specifically, the base station may send, according to the location information reported by the edge UE in the first message, the relay UE located near the edge UE and in the optimal communication range to the edge UE through the second message.

With regard to the specific behavior of the base station and the specific content of the second message, reference may be made to the following description in relation to the embodiment shown in fig. 3.

Therefore, by means of direct indication of the base station, the edge UE can know the available candidate relay UEs in the periphery without performing relay discovery operation. Further, after the edge UE can know the available neighboring candidate relay UEs according to the second message, it needs to actually measure the actual path quality of the direct communication path between the edge UE and each candidate relay UE, so as to select the most suitable candidate relay UE (i.e., the preferred relay UE) from the actual path quality to establish the PC5 link.

In one implementation, one or more candidate relay UEs included in the second message may belong to the local base station or the neighboring base station.

In one implementation, the identity of the one or more candidate relay UEs included in the second message may be an ID of each candidate relay UE. The ID is unique for uniquely identifying the UE. For example, the ID may be a cell-Radio Network Temporary Identifier (C-RNTI), a Globally Unique Temporary UE Identifier (GUTI).

In one implementation, the second message may further include a link quality threshold for relay selection.

For example, the second message may include an RSRP threshold that the base station configured to the edge UE for selecting a preferred relay UE from the plurality of candidate relay UEs. Accordingly, the edge UE determines, as the preferred relay UE, a candidate relay UE having an RSRP value higher than the RSRP threshold among RSRPs of direct communication links with one or more candidate relay UEs.

In one implementation, the selecting a preferred relay UE from the one or more candidate relay UEs in step S103 may include the steps of: broadcasting a direct communication request, wherein the direct communication request includes an identification of the one or more candidate relay UEs; determining the preferred relay UE based on the responses of the one or more candidate relay UEs.

In particular, the direct communication request may be used to request the receiver (i.e., the relay UE) to establish direct communication with the sender (i.e., the edge UE). In this embodiment, the direct communication request broadcast by the edge UE carries the identifier of one or more candidate relay UEs indicated by the base station through the second message, and only candidate relay UEs with consistent identifiers may respond to the direct communication request. That is, for a relay UE that identifies a direct communication request that does not appear in the broadcast, the relay UE that received the direct communication request does not respond even if the relay UE is located near an edge UE.

Further, a direct communication request is received and the RSRP of the direct communication link with the edge UE is measured by the broadcasted candidate relay UE. And replies to the direct communication request when the RSRP is confirmed to be good.

In one implementation, the direct communication request may include a Quality of Service (QoS) indicator for establishing the direct communication path. Correspondingly, the candidate relay UE receiving the direct communication request and having the matched identifier may determine whether the candidate relay UE satisfies the condition according to the QoS indicator indicated in the direct communication request, the current service load of the candidate relay UE, and the like, and further determine whether to respond.

In a variation, the selecting a preferred relay UE from the one or more candidate relay UEs in step S103 may include the steps of: unicast a direct communication request to the one or more candidate UEs, respectively; determining the preferred relay UE based on the responses of the one or more candidate relay UEs.

For example, when the first message includes only one candidate relay UE, the edge UE may unicast the direct communication request directly to the candidate relay UE.

For another example, when the first message includes a plurality of candidate relay UEs, the edge UE may unicast the live communication request to each candidate relay UE.

In one implementation, the responding candidate relay UE may send a direct security mode control message to the edge UE.

In one implementation, the determining the preferred relay UE according to the response of the one or more candidate relay UEs may include: when only the response message of a single candidate relay UE is received, measuring the link quality between the candidate relay UE and the response, and determining the candidate relay UE of the response as the preferred relay UE according to the measurement result.

For example, the actual measured RSRP with the responding candidate relay UE may be compared with the RSRP threshold configured by the base station, and if the actual measured RSRP is greater than or equal to the RSRP threshold, the responding candidate relay UE is determined as the preferred relay UE.

In one implementation, the determining the preferred relay UE according to the response of the one or more candidate relay UEs may include: and when response messages of a plurality of candidate relay UEs are received, determining the preferred relay UE according to the link quality between the preferred relay UE and each candidate relay UE responding.

For example, RSRPs actually measured between each candidate relay UE responding to the relay UE may be sorted, an RSRP with a maximum value greater than an RSRP threshold configured by the base station is selected from the sorted RSRPs, and the candidate relay UE corresponding to the selected RSRP is taken as the preferred relay UE.

In one implementation, after determining the preferred relay UE, the edge UE may reply with a direct security mode complete message to the preferred relay UE.

Further, the candidate relay UE receiving the direct security mode complete message may send a direct communication accept message to the edge UE to instruct the edge UE to accept its direct communication request.

Further, the base station releases the Uu path with the edge UE, thereby completing the transition of the Uu path to the PC5 path.

Thus, for the edge UE side, the present embodiment provides a more effective method for switching the Uu path to the direct communication path, which can greatly reduce the path switching delay. Specifically, the first message sent by the edge UE does not carry the link quality measurement result with the surrounding candidate relay UEs, but reports its own position. Correspondingly, the candidate relay UEs available around the edge UE are directly indicated in the second message sent by the base station for the edge UE to select. Because the edge UE does not need to execute the relay discovery process, the time delay of the three steps of measurement, measurement report and base station decision can be saved. Further, signaling overhead during path switching can be greatly reduced.

That is, the edge UE adopting the scheme of the present embodiment does not need to perform the relay discovery procedure, thereby saving signaling overhead.

Further, when the base station judges the path switching, the base station selects the candidate relay UE for the edge UE according to the position of the edge UE, and the edge UE can directly initiate a direct communication request without measuring the RSRP between the edge UE and all the relay UEs around. Therefore, the edge UE does not perform path switching based on measurement, and the time delay of path switching is reduced.

Further, the edge UE may only measure RSRP with the candidate relay UEs responding to its direct communication request, which is beneficial for reducing power consumption of the edge UE.

Fig. 2 is a schematic structural diagram of a device for switching a Uu path to a direct communication path according to an embodiment of the present invention. Those skilled in the art understand that the switching device 2 from the Uu path to the direct communication path in this embodiment may be used to implement the method technical solution described in the embodiment of fig. 1.

Specifically, referring to fig. 2, the apparatus 2 for switching the Uu path to the direct communication path according to this embodiment may include: a sending module 21, configured to send a first message, where the first message includes location information of an edge UE; a receiving module 22, configured to receive a second message, where the second message includes an identification of one or more candidate relay UEs, and the one or more candidate relay UEs are determined according to the location information of the edge UE; a switching module 23, configured to select a preferred relay UE from the one or more candidate relay UEs, and establish a direct communication path with the preferred relay UE.

For more details of the operation principle and the operation mode of the Uu path to direct communication path switching device 2, reference may be made to the description in fig. 1, and details are not repeated here.

Fig. 3 is a flowchart of a method for indicating candidate relay UEs according to an embodiment of the present invention.

The present embodiment may be performed by the base station side, such as by a base station on the base station side. By implementing the scheme of the embodiment shown in fig. 3, the base station can directly indicate available candidate relay UEs to the edge UE requesting path switching, so as to reduce the delay of path switching.

Specifically, referring to fig. 3, the method for indicating candidate relay UEs according to this embodiment may include the following steps:

step S301, receiving a first message, wherein the first message includes location information of an edge UE;

step S302, selecting one or more candidate relay UE from a preset available relay UE list according to the position information of the edge UE;

step S303, generating and transmitting a second message based on the one or more candidate relay UEs.

Those skilled in the art understand that the steps S301 to S403 may be regarded as execution steps corresponding to the steps S101 to S102 in the embodiment shown in fig. 1, and the two steps are complementary in specific implementation principle and logic. Therefore, the explanation of the terms in this embodiment can refer to the description of the embodiment shown in fig. 1, and will not be repeated here.

In one specific implementation, the base station may maintain a list of available relay UEs under the base station and the neighboring base station in real time, that is, the preset list of available relay UEs.

Specifically, the maintenance operation may include: deleting the relay UE which does not have the condition for relaying from a preset available relay UE list; adding new relay UE (user equipment) to be a relay in a preset available relay UE list; the location information for each relay UE is saved.

The relay UE is dynamically changing and when the relay UE becomes poor in link quality with the base station due to mobility or other reasons, the relay UE is no longer a relay UE. At this time, the base station may remove the relay UE from the preset list of available relay UEs.

On the contrary, although the other UE is not the relay UE before, the UE may become the relay UE at this time because the mobility and the link quality between the base stations become good. At this time, the base station may add the UE to a preset list of available relay UEs.

For example, the method for indicating candidate relay UEs according to this embodiment may further include the steps of: receiving capability report information; and determining whether to add the UE sending the capability reporting information to the preset available relay UE list or to delete the UE sending the capability reporting information from the preset available relay UE list according to the capability reporting information.

The capability reporting information may include: location information, load information, capability of having relay service of the relay UE.

In response to receiving the capability report information, the base station can know which UEs at the positions of the base station are relay UEs, and can serve as relays to provide relay services for the edge UEs.

Further, the base station may obtain the relay UE information of the neighboring base station from the neighboring base station through the Xn interface, and maintain a preset available relay UE list of the base station. The Xn interface is an interface between the ng-eNB and the eNB/gNB among the independent networking wireless nodes.

In one implementation, when receiving the first message, the base station may traverse the preset list of available relay UEs according to the location information in the first message, so as to send the relay UEs located near the edge UE and within the optimal communication range to the edge UE through the second message.

For example, the step S302 may include the steps of: and determining the relay UE which is positioned in a preset radius range by taking the position of the edge UE as the center of a circle in the preset available relay UE list as the one or more candidate relay UEs.

Specifically, the UE and the UE may perform direct communication within a certain range, where the range is the optimal communication range, that is, the range is within a preset radius using the position of the edge UE as a center of a circle. And there are many factors that affect the link quality of the direct communication path between two UEs, such as the distance between two UEs, whether there is an obstacle between two UEs, and the like.

Because there are many influencing factors, the base station preferably performs the first re-screening according to the distance (i.e. the preset radius) to generate the second message when performing step S102. And finally selecting between the UE and the UE according to the actually measured RSRP.

In one implementation, the preset radius is associated with at least the location information of the edge UE, the transmit power of the relay UE, and/or the transmit power of the edge UE.

For example, the edge UEs are currently located at different positions, and the preset radius may be different.

For another example, the specific value of the preset radius may be adjusted according to the communication capability, such as the transmission power of the edge UE and/or the relay UE.

In view of the above, for the base station side, the present embodiment provides a more efficient candidate relay UE indication method, which can greatly reduce the signaling overhead during path switching. Specifically, the base station maintains a preset available relay UE list, and selects a suitable candidate relay UE from the list to indicate to the edge UE after receiving the first message. It is not necessary for the base station to receive the link quality with each candidate relay UE measured by the edge UE, making it possible to reduce signaling overhead. Furthermore, the base station does not need to make a decision according to the link quality measurement result, so that the time delay can be reduced.

That is, the base station maintains a preset available relay UE list of the base station and the neighboring base station, and when the edge UE needs to relay the service, the base station can provide the edge UE with the auxiliary information.

Fig. 4 is a schematic structural diagram of a candidate relay UE indication apparatus according to an embodiment of the present invention. Those skilled in the art understand that the candidate relay UE indication apparatus 4 according to this embodiment may be used to implement the method technical solution described in the embodiment of fig. 3.

Specifically, referring to fig. 4, the candidate relay UE indicating apparatus 4 according to this embodiment may include: a receiving module 41, configured to receive a first message, where the first message includes location information of an edge UE; a selecting module 42, configured to select one or more candidate relay UEs from a preset list of available relay UEs according to the location information of the edge UE; an indicating module 43, configured to generate and transmit a second message based on the one or more candidate relay UEs.

For more details of the operation principle and the operation mode of the candidate relay UE indication apparatus 4, reference may be made to the related description in fig. 3, which is not repeated here.

Further, the embodiment of the present invention also discloses a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the computer program executes the technical solution of the method described in the embodiment shown in fig. 1 or fig. 3. Preferably, the storage medium may include a computer-readable storage medium such as a non-volatile (non-volatile) memory or a non-transitory (non-transient) memory. The storage medium may include ROM, RAM, magnetic or optical disks, etc.

Further, an embodiment of the present invention further discloses a terminal, which includes a memory and a processor, where the memory stores a computer program capable of running on the processor, and the processor executes the technical solution of the method in the embodiment shown in fig. 1 when running the computer program. Specifically, the terminal may be a UE.

Further, the embodiment of the present invention further discloses a base station, which includes a memory and a processor, where the memory stores a computer program capable of running on the processor, and the processor executes the technical solution of the method in the embodiment shown in fig. 3 when running the computer program. Specifically, the base station may be an NR base station.

The technical scheme of the invention can be suitable for a 5G (5generation) communication system and can also be suitable for various communication systems of subsequent evolution, such as 6G, 7G and the like.

The technical scheme of the invention is also applicable to different network architectures, including but not limited to a relay network architecture, a dual link architecture, and a Vehicle-to-event architecture.

A Base Station (BS) in the embodiment of the present application, which may also be referred to as a base station device, is a device deployed in a radio access network to provide a wireless communication function. For example, the device providing the base station function in the 2G network includes a Base Transceiver Station (BTS) and a Base Station Controller (BSC), the device providing the base station function in the 3G network includes a node B (NodeB) and a Radio Network Controller (RNC), the device providing the base station function in the 4G network includes an evolved node B (eNB), the device providing the base station function in the Wireless Local Area Network (WLAN) is an Access Point (AP), the device providing the base station function in the 5G New Radio (New Radio, NR) includes a node B (gnb), and the device providing the base station function in a future New communication system.

A terminal in this embodiment may refer to various forms of User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a Mobile Station (MS), a remote station, a remote terminal, a mobile device, a user terminal, a terminal device (terminal equipment), a wireless communication device, a user agent, or a user equipment. The terminal device may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with Wireless communication function, a computing device or other processing device connected to a Wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G Network or a terminal device in a future evolved Public Land Mobile Network (PLMN), and the like, which are not limited in this embodiment.

The embodiment of the present application defines the terminal-to-terminal communication interface as PC 5.

It should be understood that the term "and/or" herein is merely one type of association relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this document indicates that the former and latter related objects are in an "or" relationship.

The "plurality" appearing in the embodiments of the present application means two or more.

The descriptions of the first, second, etc. appearing in the embodiments of the present application are only for illustrating and differentiating the objects, and do not represent the order or the particular limitation of the number of the devices in the embodiments of the present application, and do not constitute any limitation to the embodiments of the present application.

The term "connect" in the embodiments of the present application refers to various connection manners, such as direct connection or indirect connection, to implement communication between devices, which is not limited in this embodiment of the present application.

In the embodiments of the present application, "network" and "system" represent the same concept, and a communication system is a communication network.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for switching a Uu path to a direct communication path, comprising:

sending a first message, wherein the first message comprises position information of an edge UE;

receiving a second message, wherein the second message comprises an identification of one or more candidate relay UEs determined from the location information of the edge UE;

selecting a preferred relay UE from the one or more candidate relay UEs, and establishing a direct communication path with the preferred relay UE.

2. The handover method of claim 1, wherein the second message further comprises a link quality threshold for relay selection.

3. The handover method according to claim 1, wherein the operation of sending the first message is performed in response to a link quality of the Uu path being below a first preset threshold.

4. The handover method of claim 1, wherein the first message further comprises a link quality of the Uu path.

5. The handover method of claim 1, wherein the selecting a preferred relay UE from the one or more candidate relay UEs comprises:

broadcasting a direct communication request, wherein the direct communication request includes an identification of the one or more candidate relay UEs;

determining the preferred relay UE based on the responses of the one or more candidate relay UEs.

6. The handover method of claim 1, wherein the selecting a preferred relay UE from the one or more candidate relay UEs comprises:

unicast a direct communication request to the one or more candidate UEs, respectively;

7. The handover method of claim 5 or 6, wherein the determining the preferred relay UE according to the response of the one or more candidate relay UEs comprises:

when only the response message of a single candidate relay UE is received, measuring the link quality between the candidate relay UE and the response, and determining the candidate relay UE of the response as the preferred relay UE according to the measurement result;

and when response messages of a plurality of candidate relay UEs are received, determining the preferred relay UE according to the link quality between the preferred relay UE and each candidate relay UE responding.

8. The handover method according to claim 5 or 6, wherein the direct communication request comprises a quality of service indicator for establishing a direct communication path.

9. A candidate relay UE indication method is characterized by comprising the following steps:

receiving a first message, wherein the first message comprises location information of an edge UE;

selecting one or more candidate relay UEs from a preset available relay UE list according to the position information of the edge UE;

and generating and transmitting a second message based on the one or more candidate relay UEs.

10. The candidate relay UE indication method of claim 9, wherein the second message further comprises a link quality threshold for relay selection.

11. The method of claim 9, wherein the first message is sent when a link quality of a Uu path is determined to be lower than a first preset threshold, wherein the Uu path is a communication link between an edge UE and a base station.

12. The candidate relay UE indication method of claim 11, wherein the first message further comprises a link quality of the Uu path.

13. The method of indicating candidate relay UEs according to claim 9, further comprising:

receiving capability report information;

and determining whether to add the UE sending the capability reporting information to the preset available relay UE list or to delete the UE sending the capability reporting information from the preset available relay UE list according to the capability reporting information.

14. The method of claim 9, wherein the preset list of available relay UEs comprises location information of each candidate relay UE.

15. The method of claim 9, wherein the preset list of available relay UEs comprises relay UEs of neighboring base stations.

16. The method of claim 9, wherein the preset list of available relay UEs is updated in real time.

17. The method of claim 9, wherein the selecting one or more candidate relay UEs from a preset list of available relay UEs according to the location information of the edge UE comprises:

and determining the relay UE which is positioned in a preset radius range by taking the position of the edge UE as the center of a circle in the preset available relay UE list as the one or more candidate relay UEs.

18. The method of claim 17, wherein the preset radius is associated with at least location information of the edge UE, a transmit power of the relay UE, and/or a transmit power of the edge UE.

19. A Uu path to direct communication path switching apparatus, comprising:

a sending module, configured to send a first message, where the first message includes location information of an edge UE;

a receiving module, configured to receive a second message, wherein the second message includes an identification of one or more candidate relay UEs, and the one or more candidate relay UEs are determined according to the location information of the edge UE;

a switching module, configured to select a preferred relay UE from the one or more candidate relay UEs, and establish a direct communication path with the preferred relay UE.

20. An apparatus for indicating candidate relay UE, comprising:

a receiving module, configured to receive a first message, where the first message includes location information of an edge UE;

a selection module, configured to select one or more candidate relay UEs from a preset available relay UE list according to the location information of the edge UE;

an indication module configured to generate and transmit a second message based on the one or more candidate relay UEs.

21. A storage medium having a computer program stored thereon, the computer program, when being executed by a processor, performing the steps of the method according to any one of claims 1 to 18.

22. A terminal comprising a memory and a processor, the memory having stored thereon a computer program operable on the processor, wherein the processor, when executing the computer program, performs the steps of the method of any of claims 1 to 8.

23. A base station comprising a memory and a processor, the memory having stored thereon a computer program operable on the processor, wherein the processor, when executing the computer program, performs the steps of the method of any of claims 9 to 18.