CN111294766A

CN111294766A - Condition switching method and device, storage medium and terminal

Info

Publication number: CN111294766A
Application number: CN201910661425.XA
Authority: CN
Inventors: 邓云
Original assignee: Spreadtrum Communications Shanghai Co Ltd
Current assignee: Spreadtrum Communications Shanghai Co Ltd
Priority date: 2019-07-22
Filing date: 2019-07-22
Publication date: 2020-06-16
Anticipated expiration: 2039-07-22
Also published as: CN111294766B

Abstract

A method and device for switching condition, a storage medium and a terminal are provided, the method comprises: receiving a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and the configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user terminal; in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters; when a candidate target cell with priority switching exists, initiating switching; and synchronizing and randomly accessing the candidate target cell of the priority switching. The scheme of the invention can meet the selection of a plurality of target cells and the requirement of the UE for developing the V2X service.

Description

Condition switching method and device, storage medium and terminal

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for conditional switching, a storage medium, and a terminal.

Background

In the discussion of 3GPP, the protocol preparation introduces a Conditional Handover (CHO), which is performed as follows: after receiving the handover command, a User Equipment (UE) determines whether the handover condition is satisfied, and when the handover condition is satisfied, the UE accesses the target cell by using the configuration parameters of the candidate target cell included in the handover command, synchronizes with the target cell, initiates a random access procedure in the target cell, and after sending a handover complete command (i.e., RRC reconfiguration complete), the UE performs handover to the target cell; if the handover condition is not satisfied, the UE continues to maintain the RRC connection with the source cell.

However, when the source cell configures multiple candidate target cells, the UE may determine that more than one target cell satisfies the handover condition according to the handover condition corresponding to each candidate cell, and how to select the target cell does not have any conclusion at this time. In fact, the UE may be engaged in V2X traffic in addition to conducting data traffic with the network. In this case, when the UE selects the target cell, in addition to the factors of the handover condition, it is necessary to consider whether the engaged V2X service can be smoothly performed in the target cell.

There is a need for a conditional handover method that can meet the requirements of selecting multiple target cells and the UE developing V2X service.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method and apparatus for conditional handover, a storage medium, and a terminal, which can meet the requirements of selecting a plurality of target cells and developing a V2X service by a UE.

To solve the foregoing technical problem, an embodiment of the present invention provides a method for conditional switching, including: receiving a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and the configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user terminal; in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters; when a candidate target cell with priority switching exists, initiating switching; and synchronizing and randomly accessing the candidate target cell of the priority switching.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters includes: determining whether there is a candidate target cell configured V2X transmission resource only for the user terminal; if so, taking the set of one or more candidate target cells to which the V2X transmission resources only for the user terminal belong as updated candidate target cells to determine the candidate target cells for the preferential handover.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further includes: determining, among the updated candidate target cells, the candidate target cell for the preferential handover to satisfy one or more of: the maximum number or the highest proportion of sub-channels with the RSRP lower than a preset RSRP threshold value on the PSCCH/PSSCH; the number of the sub-channels with the RSSI lower than a preset RSSI threshold value on the PSCCH/PSSCH is maximum or the proportion is highest; CBR on PSCCH/PSSCH is lowest.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further includes: determining the candidate target cell for the preferential handover in the updated candidate target cells so that the weighted average of one or more of the following parameter values reaches a preset threshold value: the number or proportion of sub-channels with RSRP lower than a preset RSRP threshold value on the PSCCH/PSSCH; the number or proportion of sub-channels with RSSI (received signal strength indicator) on the PSCCH/PSSCH lower than a preset RSSI threshold value; CBR on PSCCH/PSSCH.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters includes: determining whether a sensing mechanism for which the V2X transmission resource configured for the candidate target cell has been performed for a preset duration exists; and if so, taking the set of one or more candidate target cells which have executed the sensing mechanism for the preset time length as the updated candidate target cells to determine the candidate target cells for the priority switching.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further includes: determining, among the updated candidate target cells, the candidate target cell for the preferential handover to satisfy one or more of: the maximum number or the highest proportion of sub-channels with the RSRP lower than a preset RSRP threshold value on the PSCCH/PSSCH; the number of the sub-channels with the RSSI lower than a preset RSSI threshold value on the PSCCH/PSSCH is maximum or the proportion is highest; CBR on PSCCH/PSSCH is lowest; and the candidate target cell has the strongest signal at the frequency point where the candidate target cell is located.

Optionally, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further includes: determining whether the frequency of the candidate target cell is the same as the frequency of the current cell in which the user terminal is positioned; and if so, taking the set of one or more candidate target cells with the same frequency as the current cell in which the user terminal is positioned as the updated candidate target cell to determine the candidate target cell for the preferential handover.

To solve the foregoing technical problem, an embodiment of the present invention provides a device for switching conditions, including: a receiving module, adapted to receive a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user equipment; a determining module, adapted to determine whether there is a candidate target cell for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying a handover trigger condition among the candidate target cells; an initiating module adapted to initiate a handover when there is a candidate target cell for a prioritized handover; and the synchronous and random access module is suitable for synchronously and randomly accessing the candidate target cell with the priority switching.

To solve the above technical problem, an embodiment of the present invention provides a storage medium having stored thereon computer instructions, which when executed perform the steps of the above method for conditional switching.

In order to solve the above technical problem, an embodiment of the present invention provides a terminal, including a memory and a processor, where the memory stores computer instructions capable of being executed on the processor, and the processor executes the steps of the method for switching the condition when executing the computer instructions.

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

in the embodiment of the present invention, a conditional handover command is received, where the conditional handover command includes a plurality of pieces of configuration information, where the plurality of pieces of configuration information are respectively obtained by a source cell from a plurality of candidate target cells, and the configuration information of some or all of the candidate target cells includes V2X transmission resources configured by the candidate target cells for a user equipment; in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters; when a candidate target cell with priority switching exists, initiating switching; and synchronizing and randomly accessing the candidate target cell of the priority switching. By adopting the scheme, when a plurality of candidate target cells meeting the switching triggering condition exist in the plurality of candidate target cells, whether the candidate target cells with priority switching exist is determined according to a plurality of preset parameters, and the configuration information of each candidate target cell contains V2X transmission resources configured by the candidate target cell for the user terminal, so that the selection of the plurality of target cells and the requirement of the UE for carrying out V2X service can be met.

Further, the method can be used for preparing a novel materialGroundDetermining whether a Sensing (Sensing) mechanism for which the V2X transmission resource configured for the candidate target cell has been executed for a preset time length exists; if so, taking the set of one or more candidate target cells which have executed the sensing mechanism for the preset time as the updated candidate target cells to determine the priority switchingAnd changing the candidate target cell. In the embodiment of the present invention, it is determined whether a Sensing mechanism for a preset duration has been executed for V2X transmission resources configured for a candidate target cell, and if the duration is shorter than the preset duration, the UE can only randomly select transmission resources in the resource pool, and at this time, the probability of a collision with transmission resources selected by other transmission UEs is very high, so if a certain candidate target cell already satisfies a handover trigger condition, and the UE has completed a Sensing mechanism for the transmission resource pool configured for the cell, the UE prefers the cell as a handover target cell.

Further, the UE measures RSRP or RSSI on each sub-channel in the transmission resource pool, and if the measured RSRP or RSSI is lower than a preset threshold, it indicates that the number of UEs currently using the sub-channel is small or the UEs are far away from the UE, so that the UE selects the sub-channel lower than the preset threshold to transmit V2X data, the success probability is high, and the transmission effect is good.

Drawings

FIG. 1 is a data flow diagram of a conditional switch method in the prior art;

FIG. 2 is a flow chart of a conditional switching method according to an embodiment of the present invention;

FIG. 3 is a flowchart of one embodiment of step S22 of FIG. 2;

FIG. 4 is a flowchart of another embodiment of step S22 of FIG. 2;

FIG. 5 is a flowchart of yet another embodiment of step S22 of FIG. 2;

fig. 6 is a data flow diagram of a conditional switching method according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a condition switching apparatus according to an embodiment of the present invention.

Detailed Description

In Release 12, LTE introduces Direct Communication (ProSe Direct Communication). UE a and UE B (which may be multiple UEs) may communicate directly therebetween via a PC5 interface.

There are two modes of resource allocation, one is a scheduled resource allocation (scheduled resource allocation), which is configured by the base station through dedicated signaling; one is an automatic resource selection (autonomous resource selection), in which a base station may provide a resource pool for direct communication to a UE through a system message or RRC signaling, and the UE selects a resource for direct communication from the resource pool. If the transmitted UE (Transmitter UE) is not in the network coverage range, the UE selects resources for direct communication from a pre-configured resource pool in an automatic resource selection mode.

Based on direct communication, 3GPP also supports Vehicle-to-event (V2X), where a certain UE sends a V2X message to multiple UEs. It should be noted that both the receiving UE and the sending UE may be within the network coverage, neither may be within the network coverage, or some UEs may be within the network coverage.

As previously mentioned, in 3GPP discussions, the protocol preparation introduces a Conditional Handover (CHO).

Referring to fig. 1, fig. 1 is a data flow diagram of a conditional switching method in the prior art. The condition switching method may include steps S101 to S107, and the respective steps are explained below.

In step S101, the source cell 102 sends a CHO request to the candidate target cell 103.

In step S102, the candidate target cell 103 configures the necessary parameters for the UE101 according to the parameters in the CHO request.

Specifically, the candidate target cell 103 configures the necessary parameters for the UE101 according to the parameters in the CHO request. The CHO request includes information such as capability information of the UE101, information of a currently established radio bearer, measurement configuration, and a conditional handover trigger condition, according to which the candidate target cell allocates a suitable radio resource to the UE101 to satisfy a service requirement of the radio bearer established by the UE101, and configures parameters such as a random access resource for the UE101 to access the candidate target cell.

In step S103, the source cell 102 receives CHO request acknowledgement information from the candidate target cell 103.

In step S104, the UE101 receives a conditional handover command from the source cell 102.

In step S105, the UE101 determines whether the handover condition is satisfied, i.e., whether the conditional handover trigger condition is satisfied.

In the protocol preparation-introduced conditional handover procedure, the conditional handover command may include a handover condition, for example, whether the signal quality of the candidate target cell is higher than that of the serving cell by a predetermined offset or other suitable condition is determined, and after the UE101 receives the handover command, the UE101 evaluates the signal quality of the candidate target cell, and may further determine whether the handover condition is satisfied.

In step S106, the UE101 initiates handover when the handover condition is satisfied.

In step S107, the UE101 synchronizes and randomly accesses the candidate target cell 103.

It should be noted that, when the handover condition is satisfied, the UE101 may access the target cell by using the configuration parameters of the candidate target cell included in the handover command, acquire synchronization with the target cell, and initiate a random access procedure to access the target cell. After sending the handover complete command (i.e. RRC reconfiguration complete), the UE performs handover to the target cell; if the handover condition is not satisfied, the UE continues to maintain the RRC connection with the source base station.

The source base station may configure a plurality of candidate target cells and corresponding handover conditions. And after the UE receives the CHO, the UE continues to maintain RRC connection with the source cell, and during the period, the UE continues to execute measurement according to the measurement configuration configured by the source base station and reports the adjacent cells meeting the reporting condition. The source base station may adjust the handover condition, or adjust the candidate target cell, or send the handover command of the unconditional handover at any time according to the actual situation. Therefore, the source base station needs to grasp the channel environment change of the UE in real time, so as to make a decision in time, and avoid that the UE switches to an unsuitable neighboring cell, if the UE switches to a neighboring cell that is not the strongest on a certain frequency, after the UE switches to a non-strongest neighboring cell, uplink and downlink signal transmission of the UE will receive great interference, the base station may make a decision to switch again, and the switching process will affect the data transmission rate, thereby affecting the user experience.

The inventor of the present invention finds, through research, that in an existing application scenario, when a source base station configures a plurality of candidate target cells, a UE may determine, according to a handover condition corresponding to each candidate cell, that more than one target cell satisfies the handover condition, and at this time, no conclusion is made on how to select the target cell. In addition, the UE is engaged in V2X service in addition to conducting data service with the network. In this case, when the UE selects the target cell, in addition to the factors of the handover condition, it is necessary to consider whether the engaged V2X service can be smoothly performed in the target cell. However, the existing flow cannot meet the above requirements.

In the embodiment of the present invention, a conditional handover command is received, where the conditional handover command includes a plurality of pieces of configuration information, where the plurality of pieces of configuration information are respectively obtained by a source cell from a plurality of candidate target cells, and the configuration information of some or all of the candidate target cells includes V2X transmission resources configured by the candidate target cells for a user equipment; in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters; when a candidate target cell with priority switching exists, initiating switching; and synchronizing and randomly accessing the candidate target cell of the priority switching. By adopting the scheme, when a plurality of candidate target cells meeting the switching triggering condition exist in the plurality of candidate target cells, whether the candidate target cells for preferential switching exist is determined according to a plurality of preset parameters, and the configuration information of each candidate target cell contains V2X transmission resources configured by the candidate target cell for the user terminal, so that the selection of the plurality of target cells and the requirement of the UE for carrying out V2X service can be met.

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

Referring to fig. 2, fig. 2 is a flowchart of a conditional access method according to an embodiment of the present invention. The condition switching method includes steps S21 to S24:

step S21: receiving a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and the configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user terminal;

in this step, a conditional handover command may carry a plurality of the configuration information, that is, a conditional handover command includes parameters configured by a plurality of candidate target cells, or a plurality of conditional handover commands respectively carry parameters configured by each candidate target cell for the user equipment, that is, configured V2X transmission resources.

Step S22: in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters;

step S23: when a candidate target cell with priority switching exists, initiating switching;

step S24: and synchronizing and randomly accessing the candidate target cell of the priority switching.

In a specific implementation of step S21, a CHO request may be sent by the source cell to the candidate target cells, and then each candidate target cell configures necessary parameter information for the user equipment, where the configured necessary parameter information is referred to as configuration information, and the configuration information may include V2X transmission resources. Each candidate target cell may further send request acknowledgement information to the source cell, where the request acknowledgement information may include the configuration information. As can be seen from the above, the conditional handover command includes a plurality of configuration information, so that the UE can determine the V2X transmission resource in the configuration information.

Specifically, 3GPP is investigating to introduce V2X in the 5G New air interface (New Radio, NR). Because the 5G system can provide larger bandwidth and lower time delay, the service requirement of V2X can be better met. And 3GPP has agreed that NR V2X may transmit V2X traffic in unicast (unicast), multicast (groupcast) or broadcast manner, and when transmitting UE in unicast or groupcast, feedback may be introduced.

In NR V2X, the resource allocation scheme in LTE is basically extended, such as introducing mode 1: the base station schedules transmission resources for V2X data for the UE; mode 2: the UE determines a transmission resource for the V2X data, and the UE selects the transmission resource based on a network configured resource pool or a pre-configured resource pool. During V2X transmission, a transmitting UE sends Sidelink Control Information (SCI) on a Physical Sidelink Control Channel (PSCCH), where the SCI indicates the location, number, modulation and coding scheme, and other parameters of a radio resource block occupied by V2X data, and also includes identification information of a receiving UE, and the receiving UE knows whether V2X data is to be received by itself through the SCI, and receives V2X data on a corresponding PSCCH according to the content in the SCI.

In the specific implementation of step S22, for the UE in the connected state, while data communication with the core network is performed, V2X service may be performed, and when the network configures CHO for the UE, the UE needs to evaluate the radio link status of the Uu interface and also considers the requirement of V2X service. When the UE finds that a plurality of candidate cells satisfy the CHO handover triggering condition, the UE may be configured to select, as a handover target cell, a cell that is most favorable for performing the V2X service among the plurality of cells satisfying the handover triggering condition.

Specifically, the UE accesses a cell governed by a serving base station, for example, a primary serving cell (PCell), establishes Radio Resource Control (RRC), configures measurement of the serving cell and a neighboring cell for the UE by the PCell, may configure the UE to measure measurements on different frequencies through RRC signaling, and executes the measurement according to a measurement requirement, and sends a measurement report to the serving base station when a reporting condition is satisfied.

The UE not only performs a common communication service, i.e., performs data interaction with the base station through the Uu interface, but also performs a V2X service. Because the UE is in the connected state, the UE indicates to the serving base station through RRC signaling that it expects to carry out V2X service (transmission V2X), and after receiving the indication of the UE, the serving base station may allocate V2X transmission resources to the UE in a Mode1 manner, that is, in a base station scheduling manner; the Mode2 may also be adopted, at this time, the base station may configure a V2X transmission resource pool for the UE through RRC signaling or system message, and the UE selects an appropriate resource from the resource pool to transmit V2X data.

Referring to fig. 3, fig. 3 is a flowchart of an embodiment of step S22 in fig. 2. The step of determining whether there are candidate target cells for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying the handover trigger condition among the candidate target cells may include steps S31 to S32, and the following steps are described.

In step S31, it is determined whether there is a candidate target cell configured V2X transmission resource only for the user terminal.

Specifically, by determining that the V2X transmission resource configured by the candidate target cell is only used for the UE, it may be determined that the base station to which the candidate target cell belongs knows that the UE is developing the V2X service after receiving the conditional handover request about the UE, and decides to allocate the V2X transmission resource to the UE in a Mode1 manner, that is, in a manner of scheduling by the base station. The parameter configured for the UE by the base station to which the candidate target cell belongs may indicate whether to adopt the mode1 resource scheduling manner, so that the UE may conveniently confirm whether the V2X transmission resource is only used for itself.

It can be understood that, if the V2X transmission resource configured by the candidate target cell is not only used for the UE, it can be determined that the base station to which the candidate target cell belongs adopts the Mode2 after receiving the conditional handover request for the UE, that is, the V2X transmission resource pool is configured for the UE.

It should be noted that, when the UE determines whether the V2X transmission resource configured by the candidate target cell is only used for the UE, that is, when the Mode1 resource scheduling manner is adopted, because the transmission resource configured by the candidate target cell for Mode1 also includes a plurality of configuration parameters, such as a time-frequency position of a transmission resource of PSCCH, a time-frequency position of a transmission resource of PSSCH, a transmission power setting value, a modulation and demodulation mechanism used for transmitting V2X data, and the like, the plurality of preset parameters at least include a plurality of configuration parameters included in the transmission resource of Mode 1.

In step S32, the set of one or more candidate target cells to which the V2X transmission resources only for the user terminal belong is taken as an updated candidate target cell to determine the candidate target cell for the preferential handover, if any.

Specifically, if there are candidate target cells that allocate V2X transmission resources for the UE by means of base station scheduling, these candidate target cells may be prioritized. And then randomly selecting among the candidate target cells or selecting by synthesizing other parameters.

With reference to fig. 2 again, in a specific implementation manner of step S22 in the embodiment of the present invention, when there are multiple candidate target cells that satisfy the handover triggering condition, the step of determining whether there is a candidate target cell for a preferential handover according to multiple preset parameters may further include: and determining the candidate target cell of the priority switching in the updated candidate target cells.

Specifically, the candidate target cell for the preferential handover may be determined in the updated candidate target cells so as to satisfy one or more of the following:

the number of sub-channels with Reference Signal Receiving Power (RSRP) lower than a preset RSRP threshold is the largest or the ratio is the highest on a Physical Sidelink Control Channel (PSCCH)/(or) -Physical Sidelink shared Channel (PSCCH);

the number of sub-channels with Received Signal Strength Indication (RSSI) lower than a preset RSSI threshold value on the PSCCH/PSSCH is the largest or the proportion is the highest;

the Channel occupancy (CBR) on PSCCH/psch is lowest.

In the embodiment of the invention, the UE measures the RSRP or RSSI on each sub-channel in the transmission resource pool, if the RSRP or RSSI is lower than the preset threshold, the UE which uses the sub-channel currently is less in quantity or is far away from the UE, therefore, the UE selects the sub-channel which is lower than the preset threshold to transmit the V2X data, the success probability is higher, and the transmission effect is better. When the transmission UE selects the transmission resource in the resource pool based on the sub-channel for the granularity, one sub-channel may include a plurality of physical resource blocks, and the specific number may be configured by a system message or dedicated signaling.

In the embodiment of the invention, the UE measures the channel occupancy rate on the PSCCH/PSSCH, and the lower the channel occupancy rate is, the lower the number of the UE currently using the subchannel is, so that the UE selects the subchannel lower than the preset threshold value to transmit the V2X data, the success probability is higher, and the transmission effect is better.

In another specific implementation manner of step S22 of the embodiment of the present invention, in the candidate target cells, when there are multiple candidate target cells that satisfy the handover trigger condition, the step of determining whether there is a candidate target cell for preferential handover according to multiple preset parameters may further include: and determining the candidate target cell of the priority switching in the updated candidate target cells.

Specifically, the candidate target cell for the preferential handover may be determined in the updated candidate target cells, so that a weighted average of one or more of the following parameter values reaches a preset threshold:

the number or proportion of sub-channels with RSRP lower than a preset RSRP threshold value on the PSCCH/PSSCH;

the number or proportion of sub-channels with RSSI (received signal strength indicator) on the PSCCH/PSSCH lower than a preset RSSI threshold value;

CBR on PSCCH/PSSCH.

In the embodiment of the invention, the action of a plurality of parameters can be comprehensively considered by setting a plurality of parameters and carrying out weighted average to obtain a weighted average value, and determining the candidate target cell for preferential handover from the candidate target cells reaching the preset threshold, or determining the candidate target cell which firstly reaches the preset threshold as the candidate target cell for preferential handover.

It is noted that the weight for each parameter may be determined according to the specific requirements for multiple parameters, so that the candidate target cells determined by the weighted average are more appropriate. In the embodiment of the present invention, the specific weight setting is not limited.

Further, for the case that the base station configures the V2X transmission resource pool for the UE (i.e. Mode 2), since multiple UEs share the V2X transmission resource pool, there is a high possibility that collision occurs and the transmission of V2X fails, and in order to cope with this problem, the transmitting UE needs to introduce a Sensing mechanism. The following describes a specific sensing mechanism in NR V2X in the embodiment of the present invention. The Sensing mechanism is already adopted by the V2X in LTE, and the specific Sensing mechanism is not determined by the V2X in NR, which is based on the Sensing mechanism in LTE.

Referring to fig. 4, fig. 4 is a flowchart of another specific embodiment of step S22 in fig. 2. The step of determining whether there are candidate target cells for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying the handover trigger condition among the candidate target cells may include steps S41 to S42, and the following steps are described.

In step S41, it is determined whether there is a sensing mechanism that has been performed for a preset duration for the V2X transmission resources configured for the candidate target cell.

In step S42, if there is any, the set of one or more candidate target cells that have executed the sensing mechanism for the preset duration is used as the updated candidate target cell to determine the candidate target cell for the preferential handover.

Specifically, the UE may detect the usage status of the transmission resources for a period of time (e.g., within 1 second, the duration may be preset by a protocol, or set by the base station), detect the transmission resources reserved by other UEs and detect the received parameter values (e.g., signal power RSRP) on the transmission resources, and select its own transmission resources from the remaining transmission resources after excluding the transmission resources reserved by other UEs and the transmission resources exceeding a preset threshold of the parameter.

In the embodiment of the present invention, it may be determined whether a Sensing mechanism for a preset duration has been executed for V2X transmission resources configured for a candidate target cell, and if the duration is shorter than the preset duration, the UE may only select transmission resources randomly in the resource pool, and at this time, the probability of a conflict with transmission resources selected by other transmission UEs is very high, so if a certain candidate target cell already satisfies a handover trigger condition, and the UE has completed a Sensing mechanism for the transmission resource pool configured for the cell, that is, has completed Sensing for at least the preset duration, the UE prefers the cell as a target cell for handover.

It should be noted that, in the embodiment of the present invention, it may be determined whether there are candidate target cells configured with V2X transmission resources of mode1, and if none of the candidate target cells are configured with V2X transmission resources of mode1 or candidate cells configured with V2X transmission resources of mode1 do not satisfy the trigger condition of conditional handover, then it may be determined whether there are the following candidate target cells in the candidate target cells that satisfy the trigger condition of conditional handover: the sensing mechanism that the UE has performed equal to or more than a preset time period for the V2X transmission resource configured by the candidate target cell is adopted, so that a more detailed determination step is adopted to facilitate selection of a more appropriate candidate target cell.

In the embodiment of the present invention, it may also be directly determined whether there is a candidate target cell, and a sensing mechanism with a preset duration is already performed on the V2X transmission resource configured for the candidate target cell, so as to reduce the determination on whether the V2X transmission resource of mode1 is configured, thereby improving the determination efficiency.

the maximum number or the highest proportion of sub-channels with the RSRP lower than a preset RSRP threshold value on the PSCCH/PSSCH;

the number of the sub-channels with the RSSI lower than a preset RSSI threshold value on the PSCCH/PSSCH is maximum or the proportion is highest;

CBR on PSCCH/PSSCH is lowest.

And the candidate target cell has the strongest signal at the frequency point where the candidate target cell is located.

In the embodiment of the invention, by setting the signal of the candidate target cell at the frequency point where the candidate target cell is located, the stronger the signal is, the better the communication quality of the currently used subchannel is, so that the UE selects the subchannel with the strongest signal of the candidate target cell at the frequency point where the candidate target cell is located to transmit the V2X data, the success probability is higher, and the transmission effect is better.

In a specific implementation manner of the step S22 in the embodiment of the present invention, when there are multiple candidate target cells that satisfy the handover trigger condition, the step of determining whether there is a candidate target cell for a preferential handover according to multiple preset parameters may further include: and determining the candidate target cell of the priority switching in the updated candidate target cells.

CBR on PSCCH/PSSCH.

For more contents of determining the candidate target cell for preferential handover according to the parameter value or the weighted average of the parameter values, please refer to the foregoing contents, which are not described herein again.

Further, for the duration of V2X service, intra-frequency handover may be preferentially selected (e.g., may be used for cellular communications and V2X on the same frequency). Specifically, since Rx UEs are also located at this frequency during the V2X traffic development before the handover, if Tx UEs are handed over to another frequency, it may cause the V2X traffic to be interrupted.

Referring to fig. 5, fig. 5 is a flowchart of another embodiment of step S22 in fig. 2. The step of determining whether there are candidate target cells for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying the handover trigger condition among the candidate target cells may include steps S51 to S52, and the following steps are described.

In step S51, it is determined whether there is a candidate target cell having the same frequency as the current cell in which the user terminal is located.

In step S52, if there is any, the set of one or more candidate target cells having the same frequency as the current cell in which the user terminal is located is used as the updated candidate target cell to determine the candidate target cell for the preferential handover.

In the embodiment of the invention, the candidate target cells with the same frequency are selected for preferential switching, which is beneficial to improving the continuity of the V2X service.

CBR on PSCCH/PSSCH is lowest.

CBR on PSCCH/PSSCH.

In the embodiment of the present invention, when there are multiple candidate target cells satisfying a handover triggering condition in multiple candidate target cells, whether there is a candidate target cell for preferential handover is determined according to multiple preset parameters, and the configuration information of each candidate target cell includes V2X transmission resources configured by the candidate target cell for the user equipment, so that the selection of multiple target cells and the need of the UE for carrying out the V2X service can be satisfied.

Referring to fig. 6, fig. 6 is a data flow diagram of a conditional switching method according to an embodiment of the present invention. The condition switching method may include steps S601 to S609, and the respective steps are explained below. It should be noted that, in the method shown in fig. 6, two candidate target cells are used for illustration, however, in the embodiment of the present invention, there is no limitation on the specific number of the candidate target cells.

In step S601, the source cell 602 sends a CHO request to the first candidate target cell 603 and the second candidate target cell 604.

Specifically, when the UE simultaneously performs a common communication service and a V2X service, the UE performs measurement according to measurement configuration configured by the base station, and reports a corresponding measurement report when the UE meets a reporting condition after evaluating whether the neighboring cell meets the reporting condition. The base station (i.e. the source base station) may trigger the CHO after receiving one or more measurement reports of the UE. The source base station may select a plurality of candidate cells, and then send a CHO request to candidate target base stations to which the plurality of candidate cells belong, respectively, where the CHO request includes current configuration parameters of the UE and handover triggering conditions, where the CHO request includes configuration parameters of a signaling radio bearer and configuration parameters of a data radio bearer, and also includes information that the UE needs to perform V2X transmission, so that the candidate target base stations reasonably configure the parameters for the UE.

The multiple candidate target cells may be located on the same frequency or on different frequencies. The source base station may configure the same handover triggering condition for the multiple candidate target cells, or may configure different handover triggering conditions, where the specific handover triggering condition may be that the signal quality of the candidate target cell exceeds a preset threshold, or that the signal quality of the candidate target cell is higher than the signal quality of the PCell (primary cell) by a preset offset, and the patent does not limit the specific handover triggering condition.

In step S602, the first candidate target cell 603 configures first configuration information including first V2X transmission resources.

Specifically, the first configuration information may include a first V2X transmission resource. Because the candidate target base station is aware that the UE needs to perform V2X transmission, the candidate target base station configures a V2X transmission resource pool for the UE or configures V2X transmission resources only for the user terminal, so that V2X service can be continued using the transmission resources in the transmission resource pool after the UE is handed over.

In step S603, the source cell 602 receives first CHO request acknowledgement information, including first configuration information, from the first candidate target cell 603.

In step S604, the second candidate target cell 604 may configure second configuration information, including a second V2X transmission resource.

Specifically, the second configuration information may include a second V2X transmission resource. Because the candidate target base station is aware that the UE needs to perform V2X transmission, the candidate target base station configures a V2X transmission resource pool for the UE so that V2X service can continue using transmission resources in the transmission resource pool after the UE is handed over.

In step S605, the source cell 602 receives second CHO request acknowledgement information, including second configuration information, from the second candidate target cell 604.

In step S606, the UE601 receives a conditional handover command from the source cell 602, which includes the first configuration information and the second configuration information.

In step S607, the UE601 determines whether there is a candidate target cell for preferential handover according to a plurality of preset parameters.

In a specific implementation, whether there is a candidate target cell for preferential handover may be determined according to the foregoing methods and the methods shown in fig. 3 to fig. 5, which are not described herein again.

In step S608, when there is a candidate target cell for a priority handover, the UE601 initiates a handover.

In step S609, the UE601 synchronizes and randomly accesses the first candidate target cell 603.

It should be noted that, in step S609, the first candidate target cell 603 is taken as a candidate target cell for preferential handover, which is only used for example, and does not limit any specific implementation in the embodiment of the present invention.

In the specific implementation, more details about step S601 to step S609 are performed with reference to the step descriptions in fig. 2 to fig. 5, which are not described herein again.

Referring to fig. 7, fig. 7 is a schematic structural diagram of a condition switching apparatus according to an embodiment of the present invention. The condition switching device may include

A receiving module 71, adapted to receive a conditional handover command, where the conditional handover command includes a plurality of configuration information, where the plurality of configuration information are obtained from a plurality of candidate target cells by a source cell respectively, and the configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user equipment;

a determining module 72, adapted to determine whether there are candidate target cells for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying a handover triggering condition among the candidate target cells;

an initiating module 73 adapted to initiate a handover when there is a candidate target cell for a prioritized handover;

a synchronization and random access module 74 adapted to synchronize and randomly access the candidate target cell for the preferential handover.

For the principle, specific implementation and beneficial effects of the condition switching apparatus, please refer to the foregoing description and the related descriptions of the condition switching method shown in fig. 2 to fig. 6, which are not repeated herein.

It should be noted that the technical solution of the present invention is applicable to a 5G (5Generation) communication system, a 4G communication system, a 3G communication system, and various future new communication systems, such as 6G, 7G, and the like.

The embodiment of the invention also provides a storage medium, wherein computer instructions are stored on the storage medium, and the computer instructions execute the steps of the method when running. The storage medium may be a computer-readable storage medium, and may include, for example, a non-volatile (non-volatile) or non-transitory (non-transitory) memory, and may further include an optical disc, a mechanical hard disk, a solid state hard disk, and the like.

Specifically, in the embodiment of the present invention, the processor may be a Central Processing Unit (CPU), and the processor may also be another general-purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It will also be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM) which acts as external cache memory. By way of example and not limitation, many forms of Random Access Memory (RAM) are available, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct bus RAM (DR RAM).

The embodiment of the invention also provides a terminal, which comprises a memory and a processor, wherein the memory is stored with computer instructions capable of running on the processor, and the processor executes the steps of the method when running the computer instructions. The terminal includes, but is not limited to, a mobile phone, a computer, a tablet computer and other terminal devices.

Specifically, 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 (mobile station, MS), a remote station, a remote terminal, a mobile device, a user terminal, a terminal device (terminal device), 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 a Wireless communication function, a computing device or other processing devices 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 is not limited in this embodiment of the present application.

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 of conditional switching, comprising:

receiving a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and the configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user terminal;

in the candidate target cells, when a plurality of candidate target cells meeting a switching triggering condition exist, determining whether the candidate target cells with priority switching exist according to a plurality of preset parameters;

when a candidate target cell with priority switching exists, initiating switching;

and synchronizing and randomly accessing the candidate target cell of the priority switching.

2. The method of conditional handover according to claim 1, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters comprises:

determining whether there is a candidate target cell configured V2X transmission resource only for the user terminal;

if so, taking the set of one or more candidate target cells to which the V2X transmission resources only for the user terminal belong as updated candidate target cells to determine the candidate target cells for the preferential handover.

3. The method of conditional handover according to claim 2, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

determining, among the updated candidate target cells, the candidate target cell for the preferential handover to satisfy one or more of:

CBR on PSCCH/PSSCH is lowest.

4. The method of conditional handover according to claim 2, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

determining the candidate target cell for the preferential handover in the updated candidate target cells so that the weighted average of one or more of the following parameter values reaches a preset threshold value:

CBR on PSCCH/PSSCH.

5. The method of conditional handover according to claim 1 or 2, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters comprises:

determining whether a sensing mechanism for which the V2X transmission resource configured for the candidate target cell has been performed for a preset duration exists;

and if so, taking the set of one or more candidate target cells which have executed the sensing mechanism for the preset time length as the updated candidate target cells to determine the candidate target cells for the priority switching.

6. The method of conditional handover according to claim 5, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

CBR on PSCCH/PSSCH is lowest;

7. The method of conditional handover according to claim 5, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

CBR on PSCCH/PSSCH.

8. The method of conditional handover according to claim 5, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

determining whether the frequency of the candidate target cell is the same as the frequency of the current cell in which the user terminal is positioned;

and if so, taking the set of one or more candidate target cells with the same frequency as the current cell in which the user terminal is positioned as the updated candidate target cell to determine the candidate target cell for the preferential handover.

9. The method of conditional handover according to claim 8, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

CBR on PSCCH/PSSCH is lowest;

10. The method of conditional handover according to claim 8, wherein, in the candidate target cells, when there are multiple candidate target cells satisfying the handover trigger condition, determining whether there is a candidate target cell for preferential handover according to multiple preset parameters further comprises:

CBR on PSCCH/PSSCH.

11. An apparatus for conditional switching, comprising:

a receiving module, adapted to receive a conditional handover command, where the conditional handover command includes multiple pieces of configuration information, where the multiple pieces of configuration information are respectively obtained by a source cell from multiple candidate target cells, and configuration information of some or all candidate target cells includes V2X transmission resources configured by the candidate target cells for a user equipment;

a determining module, adapted to determine whether there is a candidate target cell for preferential handover according to a plurality of preset parameters when there are a plurality of candidate target cells satisfying a handover trigger condition among the candidate target cells;

an initiating module adapted to initiate a handover when there is a candidate target cell for a prioritized handover;

and the synchronous and random access module is suitable for synchronously and randomly accessing the candidate target cell with the priority switching.

12. A storage medium having stored thereon computer instructions which, when executed, perform the steps of the method of conditional switching according to any of claims 1 to 10.

13. A terminal comprising a memory and a processor, the memory having stored thereon computer instructions executable on the processor, wherein the processor, when executing the computer instructions, performs the steps of the method of conditional switching according to any of claims 1 to 10.