WO2020098794A1

WO2020098794A1 - Communication method and apparatus

Info

Publication number: WO2020098794A1
Application number: PCT/CN2019/118874
Authority: WO
Inventors: 严乐; 袁世通; 耿婷婷; 张宏平; 曾清海
Original assignee: 华为技术有限公司
Priority date: 2018-11-16
Filing date: 2019-11-15
Publication date: 2020-05-22
Also published as: CN111200847A

Abstract

Disclosed in the present application are a communication method and apparatus. The method comprises: a source network device sends reservation indication information of a random access channel resource to a candidate target network device; the candidate target network device sends a switching trigger condition and indication information of the random access channel resource to the source network device; the source network device sends the switching trigger condition and the indication information of the random access channel resource to a terminal device; the terminal device determines, according to the switching trigger condition and the indication information of the random access channel resource, a random access channel resource for initiating a random access; and the terminal device initiates the random access to the target network device according to the determined random access channel resource. Also disclosed is a corresponding apparatus. By using the solution of the present application, a source network device reasonably requests a candidate target network device to reserve a random access channel resource, so that waste of resources is reduced, and the success rate of switching is improved.

Description

Communication method and device

This application requires the priority of a Chinese patent application filed on November 16, 2018, with the application number 201811365827.7 and the invention titled "Communication Method and Device", the entire content of which is incorporated by reference in this application.

Technical field

This application relates to the field of communication technology, and in particular, to a communication method and device.

Background technique

In the mobile communication system, the mobility management of the connected terminal device is provided by the network, that is, the network controls which target cell the terminal device switches to and how to switch.

In order to guide the terminal equipment to switch reasonably, the network needs to measure the wireless environment in which the terminal equipment is located. The source base station sends the measurement configuration to the terminal device, and the terminal device performs measurement based on the measurement configuration. When the measurement event trigger condition is met, the terminal device reports the measurement result to the source base station. The source base station makes a handover decision based on the measurement result reported by the terminal device, and sends a handover request to the target base station. The target base station performs admission control, and if allowed, the target base station replies to the source base station with a handover request confirmation message. After receiving the handover request confirmation message, the source base station sends a handover message to the terminal device to control the terminal device to access the target base station. After receiving the handover message, the terminal device disconnects from the source base station and initiates a random access process to the target base station to obtain the timing advance (TA) value and uplink transmission resources. The target base station sends a handover complete message.

Whether the handover message can be successfully sent in the communication system depends on the quality of the service link of the source cell. Poor quality service links will cause the handover message to fail to be sent, which will affect the data transmission of the terminal device. In mobile communication systems (especially in high-frequency scenarios), the channel quality is rapidly degraded, and the rapid movement of terminal equipment or the occlusion of objects can cause the handover message to fail to be sent; or the handover message cannot be sent due to the long duration of measurement and handover preparation (When the source base station prepares to send the handover message, the quality of the wireless link has become poor).

Therefore, how to improve the success rate of handover with lower resource overhead is a problem that needs to be solved urgently.

Summary of the invention

The present application provides a communication method and device, which can improve the success rate of handover with lower resource overhead.

In a first aspect, a communication method is provided, including: receiving a second message from a source network device, the second message including: trigger switching conditions and indication information of random access channel resources; according to the trigger switching conditions and all Determining the random access channel resource indication information, determining a random access channel resource that initiates random access; and initiating random access to the target network device according to the determined random access channel resource.

In this aspect, the terminal device determines the random access channel resource that initiates random access according to the trigger switching condition and the indication information of the random access channel resource sent by the source network device, and initiates random access on the random access channel resource To improve the success rate of handover.

In a possible implementation, the indication information of the random access channel resources is used to indicate one or more of the following information: dedicated random access channel resources are reserved; dedicated random access channel resources are not reserved but Public random access channel resources are reserved; dedicated random access channel resources are not reserved and common random access channel resources are not reserved.

In this implementation manner, the indication information of the random access channel resource may have the above-mentioned various types, and the terminal device may reasonably select the random access channel resource that initiates random access according to the indication of the random access channel resource.

In another possible implementation, the second message further includes a beam signal threshold; the random access to initiate random access is determined according to the trigger switching condition and the indication information of the random access channel resource The channel resources include: in a cell that meets the triggering handover condition, a random access channel resource associated with a beam that reserves dedicated random access channel resources and meets beam measurement conditions is determined as the random access initiator Access channel resources; wherein, when the signal quality of the beam is greater than or equal to the beam signal threshold, the beam is a beam that satisfies the beam measurement condition.

In this implementation manner, the random access channel resource associated with the beam that belongs to the cell that satisfies the condition for triggering the handover, reserves the dedicated random access channel resource and meets the beam measurement condition is determined as the random access initiator random Access to channel resources improves resource utilization and handover success rate.

In yet another possible implementation manner, the determining, according to the trigger switching condition and the indication information of the random access channel resource, the random access channel resource corresponding to the beam for random access includes:

If no dedicated random access channel resource is reserved in the cell that satisfies the triggering switching condition and meets the beam measurement condition, a beam that reserves the common random access channel resource and satisfies the beam measurement condition is determined. The public random access channel resource is determined as a random access channel resource that initiates random access.

In this implementation manner, when there are no beams reserved for dedicated random access channel resources and satisfying beam measurement conditions, a beam reserved for common random access channel resources and satisfying beam measurement conditions is determined, and the common random The access channel resource is determined as the random access channel resource that initiates random access, which improves the resource utilization rate and the handover success rate.

If in the cell that meets the conditions for triggering handover, no dedicated random access channel resources are reserved for beams that satisfy the beam measurement conditions, and no common random access channel resources are reserved for beams that satisfy the beam measurement conditions, Obtaining a random access channel resource from system information broadcast by the network device to which the cell that meets the triggering switching condition belongs, and determining the acquired random access channel resource as the random access channel resource that initiates random access.

In yet another possible implementation manner, the second message further includes an identifier of one or more candidate target cells and an identifier of one or more beams under each candidate target cell, and the second message further includes a dedicated Random access channel resource information, the dedicated random access channel resource includes a preamble index and a first time-frequency resource; and / or the second message further includes common random access channel resource information, the public random access The channel resources include second time-frequency resources.

In yet another possible implementation manner, the dedicated random access channel resource is a dedicated random access channel resource associated with the beam group; and the random access is initiated to the target network device according to the determined random access channel resource In, including: sending a third message to the target network device according to the dedicated random access channel resource associated with the beam group, where the third message is used to initiate random access, and the third message includes the first beam ’s It is identified that the first beam belongs to a beam in the beam group that satisfies beam measurement conditions; a fourth message is received from the target network device through the first beam, and the fourth message is the third In response to the message, the fourth message includes uplink transmission resource information; and using the uplink transmission resource to send a fifth message to the target network device, where the fifth message is used to indicate the completion of the handover.

In this implementation, the candidate target network device groups multiple beams of the candidate target cell, assigns the same dedicated random access channel resource to different beams in the same beam group, and assigns different beam groups to different beam groups. Beams of different dedicated random access channel resources, and the terminal equipment determines the random access channel resources that initiate random access according to the dedicated random access channel resources associated with the beam group. In the random access process, it will belong to The beam identifier of a target beam that satisfies the beam measurement condition in the beam group notifies the target network device, so that the target network device can send a random access response on the target beam.

In a second aspect, a communication method is provided, including: sending a first message to a candidate target network device, the first message including reservation indication information of a random access channel resource; receiving a trigger to switch from the candidate target network device Condition and indication information of the random access channel resource, the indication information of the random access channel resource is used to indicate the reservation result of the random access channel resource; and sending a second message to the terminal device, the second message Including the trigger switching condition and the indication information of the random access channel resource.

In this aspect, the source network device reasonably requests the candidate target network device to reserve random access channel resources, which can reduce waste of resources and improve the success rate of handover.

In a possible implementation manner, the first message is of a granularity of a network device, and the first message further includes an identifier of a candidate target cell and an identifier of a beam belonging to the candidate target cell; the reservation indication The information includes information indicating whether to reserve dedicated random access channel resources; the reservation indication information is of network device granularity, cell granularity, or beam granularity.

In this implementation manner, the source network device reasonably requests the candidate target network device to reserve resources through explicit reservation indication information, which can avoid waste of resources; where the first message is network device granularity, which can reduce signaling overhead.

In another possible implementation manner, the first message is of cell granularity, and the first message further includes an identifier of the candidate target cell and an identifier of the beam belonging to the candidate target cell; the reservation indication The information includes information indicating whether to reserve dedicated random access channel resources; the reservation indication information is of cell granularity or beam granularity.

In this implementation manner, the source network device reasonably requests the candidate target network device to reserve resources through explicit reservation indication information, which can avoid the waste of resources; wherein, the first message is of cell granularity, which can reduce signaling overhead.

In yet another possible implementation manner, the reservation indication information includes a signal quality threshold of a cell and / or a signal quality threshold of a beam.

In this implementation, the source network device sends the signal quality threshold of the cell and / or the signal quality threshold of the beam to the candidate target network device, and the candidate target network device according to the signal quality threshold of the cell and / or the signal quality of the beam The threshold determines which candidate target cells or which beams are reserved for random access channel resources, which can improve the autonomy of candidate target network devices and reserve resources reasonably.

In yet another possible implementation, the indication information of the random access channel resources is used to indicate one or more of the following information: dedicated random access channel resources are reserved; dedicated random access channel resources are not reserved However, public random access channel resources are reserved; dedicated random access channel resources are not reserved and common random access channel resources are not reserved.

In this implementation manner, the indication information of the random access channel resource sent by the source network device to the candidate target network device may have the foregoing multiple types, and the source network device may reasonably request the candidate target network device to reserve resources to avoid waste of resources.

In a third aspect, a communication method is provided, including: receiving a first message from a source network device, the first message including reservation indication information of a random access channel resource; and sending a trigger switching condition to the source network device And indication information of a random access channel resource, where the indication information of a random access channel resource is used to indicate a reservation result of a random access channel resource.

In this aspect, the candidate target network device receives the reservation instruction information of the source network device, and reserves resources reasonably according to the reservation instruction information, thereby reducing waste of resources and improving the success rate of handover.

In this implementation manner, the candidate target network device receives the explicit reservation indication information of the source network device, and can reasonably reserve resources, thereby avoiding waste of resources; wherein, the first message is network device granularity, which can reduce information令 Overhead.

In this implementation manner, the candidate target network device receives the explicit reservation indication information of the source network device, and reserves resources reasonably, thereby avoiding waste of resources; wherein, the first message is of cell granularity, which can save signaling overhead .

In yet another possible implementation manner, the reservation indication information includes a signal quality threshold of a cell and / or a signal quality threshold of a beam; the first message further includes an identifier of a candidate target cell and a corresponding candidate target The measurement result of the cell, the identification of the beam belonging to the candidate target cell and the measurement result of the corresponding beam;

The method also includes:

The reservation indication information includes the signal quality threshold value of the cell. When the signal quality of the first candidate target cell is greater than or equal to the signal quality threshold value of the cell, the All beams of the first candidate target cell reserve dedicated random access channel resources; or,

The reservation indication information includes the signal quality threshold of the cell and the signal quality threshold of the beam, when the signal quality of the second candidate target cell is greater than or equal to the signal quality threshold of the cell, and the second candidate target When the signal quality of at least one beam of the cell is greater than or equal to the signal quality threshold of the beam, dedicated random access channel resources are reserved for the at least one beam.

In this implementation, the source network device sends the signal quality threshold of the cell and / or the signal quality threshold of the beam to the candidate target network device, and the candidate target network device according to the signal quality threshold of the cell and / or the signal quality of the beam The threshold determines which candidate target cells or which beams are reserved for random access channel resources, which can improve the autonomy of the candidate target network equipment and reserve resources reasonably.

In this implementation manner, the indication information of the random access channel resource sent by the source network device to the candidate target network device may have the above-mentioned types. The source network device reasonably requests the candidate target network device to reserve resources to avoid waste of resources.

In yet another possible implementation, when the indication information of the random access channel resource is used to indicate that a dedicated random access channel resource is reserved, the method further includes: sending a dedicated message to the source network device Random access channel resource information;

When the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is not reserved but the common random access channel resource is reserved, the method further includes: sending a common to the source network device Random access channel resource information.

In yet another possible implementation manner, the method further includes:

Group one or more beams under the candidate target cell to obtain one or more beam groups;

The one or more beam groups are respectively allocated corresponding dedicated random access channel resources.

In this implementation manner, considering that the candidate target network device may allocate dedicated random access channel resources to many beams, the candidate target network device allocates dedicated random access channel resources according to the beam group, which can improve resource utilization.

In yet another possible implementation manner, the method further includes:

A third message sent by the receiving terminal device according to the dedicated random access channel resource associated with the beam group, where the third message is used to initiate random access, and the third message includes the identifier of the first beam, and the third A beam is a beam in the beam group that satisfies the beam measurement conditions;

Sending a fourth message to the terminal device through the first beam, the fourth message is a response message of the third message, and the fourth message includes uplink transmission resource information;

Receiving a fifth message sent using the uplink transmission resource from the terminal device, where the fifth message is used to indicate that the handover is completed.

In this implementation, since the candidate target network device allocates dedicated random access channel resources according to the beam group, the terminal device determines the random access channel that initiates random access based on the dedicated random access channel resources associated with the beam group Resources, in the random access process, notifying the target network device of the beam identifier of a first beam belonging to the beam group and satisfying the beam measurement condition, so that the target network device can send a random access response on the first beam.

In yet another possible implementation manner, the method further includes:

Receiving a sixth message sent by the terminal device according to the dedicated random access channel resource associated with the beam group, where the sixth message is used to initiate random access;

Sending a seventh message to the terminal device through each beam included in the beam group, each seventh message is a response message of the sixth message, and each seventh message includes different uplink transmission resources;

Receiving an eighth message from the terminal device, and the uplink transmission resource that the terminal device sends the eighth message is included in one of the seventh messages received by the terminal device, the eighth message is used to indicate the completion of the handover ;

Determine a beam to communicate with the terminal device according to the uplink transmission resource used by the terminal device to send the eighth message.

In this implementation, since the candidate target network device allocates dedicated random access channel resources according to the beam group, the terminal device uses the dedicated random access channel resource associated with the beam group, and the target network device initiates random access based on the terminal device. The random access channel resource used determines the beam group associated with the random access channel resource, and the target network device sends a random access response message through each beam contained in the beam group, and each random access response message Containing different uplink transmission resources, according to the uplink transmission resources that the terminal device sends the RRC reconfiguration complete message, the first beam that communicates with the terminal device can be determined.

In yet another possible implementation manner, the method further includes:

Receiving a ninth message sent by the terminal device according to the dedicated random access channel resource associated with the beam group, where the ninth message is used to initiate random access;

Sending a tenth message to the terminal device through each beam included in the beam group, each tenth message is a response message of the ninth message, and each tenth message includes the same uplink transmission resource;

Receiving an eleventh message sent using the uplink transmission resource from the terminal device, the eleventh message is used to indicate completion of handover, the eleventh message includes an identifier of a first beam, and the first beam is Belongs to a beam in the beam group that satisfies the beam measurement condition.

In this implementation, since the candidate target network device allocates dedicated random access channel resources according to the beam group, the terminal device carries the dedicated random access channel resource associated with the beam group. The terminal device carries the RRC reconfiguration complete message The identification of the first beam enables the target network device to determine the beam to communicate with the terminal device.

In a fourth aspect, a communication device is provided, which can implement the communication method in the first aspect or any possible implementation manner of the first aspect. For example, the communication device may be a chip (such as a communication chip) or a terminal device. The above method can be implemented by software, hardware, or corresponding software executed by hardware.

In a possible implementation, the structure of the communication device includes a processor and a memory; the processor is configured to support the device to perform the corresponding function in the above communication method. The memory is used for coupling with a processor, which stores necessary programs (instructions) and / or data of the device. Optionally, the communication device may further include a communication interface for supporting communication between the device and other network elements.

In another possible implementation manner, the communication device may include a unit or module that performs the corresponding action in the above method.

In yet another possible implementation manner, a processor and a transceiver device are included, and the processor is coupled to the transceiver device, and the processor is used to execute a computer program or instruction to control the transceiver device to receive and receive information. Send; when the processor executes the computer program or instruction, the processor is also used to implement the above method. The transceiver device may be a transceiver, a transceiver circuit, or an input-output interface. When the communication device is a chip, the transceiver device is a transceiver circuit or an input-output interface.

In yet another possible implementation manner, the structure of the communication device includes a processor; the processor is configured to support the device to perform the corresponding function in the above communication method.

In yet another possible implementation manner, the structure of the communication device includes a processor, and the processor is used to couple with the memory, read instructions in the memory, and implement the above method according to the instructions.

In yet another possible implementation manner, the structure of the communication device includes a transceiver, which is used to implement the foregoing communication method.

When the communication device is a chip, the transceiver unit may be an input-output unit, such as an input-output circuit or a communication interface. When the communication apparatus is user equipment, the transceiver unit may be a transmitter / receiver or a transmitter / receiver.

In a fifth aspect, a communication device is provided, which can implement the communication method in the second aspect or the third aspect or any possible implementation manner thereof. For example, the communication device may be a chip (such as a baseband chip, or a communication chip, etc.) or a network device, and the above method may be implemented through software, hardware, or executing corresponding software through hardware.

In a possible implementation, the structure of the communication device includes a processor and a memory; the processor is configured to support the device to perform the corresponding function in the above communication method. The memory is used to couple with the processor, which stores necessary programs (instructions) and data of the device. Optionally, the communication device may further include a communication interface for supporting communication between the device and other network elements.

In another possible implementation manner, the communication device may include a unit module that performs corresponding actions in the above method.

When the communication device is a chip, the transceiver unit may be an input-output unit, such as an input-output circuit or a communication interface. When the communication device is a network device, the transceiver unit may be a transmitter / receiver (also may be referred to as a transmitter / receiver).

According to a sixth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores computer programs or instructions. When the computer programs or instructions are executed, the methods described in the above aspects are implemented.

According to a seventh aspect, there is provided a computer program product containing instructions, which when executed on a computer, causes the computer to execute the method described in the above aspects.

According to an eighth aspect, a communication system is provided, including the communication devices in the above fourth and fifth aspects.

BRIEF DESCRIPTION

1 is a schematic diagram of a communication system involved in this application;

2 is a schematic diagram of an interaction process of a communication method provided by an embodiment of the present application;

3 is a schematic diagram of an interaction process of another communication method provided by an embodiment of the present application;

4a is a schematic diagram of a random access process provided by an embodiment of this application;

4b is a schematic diagram of another random access process provided by an embodiment of this application;

4c is a schematic diagram of another random access process provided by an embodiment of the present application;

5 is a schematic structural diagram of a communication device according to an embodiment of the present application;

6 is a schematic structural diagram of another communication device provided by an embodiment of the present application;

7 is a schematic structural diagram of yet another communication device provided by an embodiment of this application;

8 is a schematic structural diagram of a simplified terminal device provided by an embodiment of the present application;

9 is a schematic structural diagram of a simplified network device provided by an embodiment of the present application.

detailed description

The following describes the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

FIG. 1 shows a schematic diagram of a communication system involved in this application. The communication system may include one or more network devices 100 (only one shown) and one or more terminal devices 200 connected to the network device 100.

The network device 100 may be a device that can communicate with the terminal device 200. The network device 100 may be any device having a wireless transceiver function. Including but not limited to: base station NodeB, evolved base station eNodeB, base station in the fifth generation (5G) communication system, base station or network equipment in future communication system, access node in Wi-Fi system, wireless Relay nodes, wireless backhaul nodes, etc. The network device 100 may also be a wireless controller in a cloud radio access network (CRAN) scenario. The network device 100 may also be a small station, a transmission reference (transmission reference point, TRP), or the like. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network device.

Terminal device 200 is a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld, wearable, or vehicle-mounted; it can also be deployed on the water, such as ships, etc .; it can also be deployed in the air, such as aircraft , Balloons and satellites. The terminal device may be a mobile phone, a tablet, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, and industrial control ( wireless terminal in industrial control), wireless terminal in self-driving (self-driving), wireless terminal in remote medical (remote medical), wireless terminal in smart grid (smart grid), transportation safety (transportation safety) Wireless terminals, wireless terminals in smart cities, wireless terminals in smart homes, etc. The embodiments of the present application do not limit the application scenarios. Terminal equipment may sometimes be called user equipment (user equipment (UE), access terminal equipment, UE unit, mobile station, mobile station, remote station, remote terminal equipment, mobile device, terminal), wireless communication device, UE Agent or UE device, etc.

It should be noted that the terms "system" and "network" in the embodiments of the present invention may be used interchangeably. "Multiple" refers to two or more. In view of this, in the embodiments of the present invention, "multiple" may also be understood as "at least two". "And / or" describes the relationship of the related objects, indicating that there can be three relationships, for example, A and / or B, which can indicate: there are three conditions: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/", unless otherwise specified, generally indicates that the related object is a "or" relationship.

In order to improve the robustness of handover, consider the mechanism of conditional handover to reduce the handover failure rate, that is, when the link quality of the source cell is still good, the source network device sends a message to the terminal device, for example, radio resource control , RRC) reconfiguration message, which carries the conditions that trigger a real handover. After receiving the message, the terminal device determines whether the condition for triggering handover is satisfied, and once it is met, the terminal device switches to the target cell that meets the condition for triggering handover. Before the source network device sends the message to the terminal device, the source network device performs conditional switching preparation with several candidate target network devices, that is, the source network device notifies the candidate target network device of the context information of the terminal device. The candidate target network device may be a terminal The device allocates dedicated random access channel (random access channel, RACH) resources or allocates common random access channel resources for terminal devices. Since dedicated RACH resources are allocated in advance, the success rate of handover is improved. However, RACH resources are allocated in advance, and if the RACH resources are not finally used, it will cause a waste of resources. For example, in a conditional handover scenario, assuming that several candidate target network devices have allocated / reserved dedicated RACH resources in advance, the terminal device determines whether the conditions for triggering handover are met after receiving the RRC reconfiguration message. It may not be satisfied for a long time or even for a long time. Even if the conditions are met, the terminal device will eventually only switch to the only target cell that meets the trigger condition, which will cause the waste of dedicated RACH resources allocated / reserved in advance. Therefore, how to reserve resources reasonably and avoid the waste of resources is a problem that needs to be solved.

It should be noted that the embodiments of the present application are not limited to conditional switching scenarios, but can also be applied to traditional switching scenarios or other scenarios that require reasonable resource reservation to avoid resource waste.

In various embodiments of the present application, a beam can be understood as a spatial resource, and can refer to a precoding vector for sending or receiving with energy transmission directivity. In addition, the sending or receiving precoding vector can be identified by index information, which can correspond to the resource identity (ID) of the configured terminal, for example, the index information can correspond to the identity or resource of the configured SSB; also It may correspond to the configured identifier or resource of the CSI-RS; it may also correspond to the configured identifier or resource of the uplink sounding reference signal (SRS). Optionally, the index information may also be index information displayed or implicitly carried by a signal or channel carried by a beam. The energy transmission directivity may refer to the precoding processing of the signal to be transmitted by the precoding vector, the signal after the precoding processing has a certain spatial directivity, and the precoding processing after receiving the precoding vector The signal has better received power, such as satisfying the reception demodulation signal-to-noise ratio, etc .; the energy transmission directivity may also mean that the same signal sent from different spatial positions received by the precoding vector has different received power. Optionally, the same communication device (such as a terminal device or a network device) may have different precoding vectors, and different devices may also have different precoding vectors, that is, corresponding to different beams. Regarding the configuration or capability of the communication device, one communication device may use one or more of multiple different precoding vectors at the same time, that is, one beam or multiple beams may be formed at the same time.

FIG. 2 is a schematic diagram of an interaction process of a communication method provided by an embodiment of the present application. among them:

S101. The source network device sends a first message to the candidate target network device, where the first message includes reservation indication information of random access channel resources.

Correspondingly, the candidate target network device receives the first message.

Through S101, the source network device prepares for switching with the candidate target network device.

Optionally, before preparing for handover, that is, before S101, the terminal device sends a measurement report to the source network device, and the measurement report may include the cell identity of the neighboring cell and the cell signal quality of the neighboring cell (eg, reference signal received power) (reference signal received power (RSRP) or reference signal received quality (RSRQ)). Optionally, the measurement report may further include at least one of an identifier of a beam belonging to a neighboring cell and a signal quality of the beam (for example, RSRP or RSRQ). The identifiers of the beams in the measurement report can be sorted according to the signal quality of the corresponding beams from high to low. The identification of the beam may be a synchronization signal block (synchronization signal and PBCH block, SSB) index (channel index) or a channel state information reference signal (channel status-information-reference signal, CSI-RS) index.

The source network device determines at least one candidate target cell based on the identification of each neighbor cell carried in the measurement report and the signal quality of the beam under each neighbor cell (different candidate target cells may belong to the same network device or different network devices) And determine which candidate target cells or which beams under the candidate target cell are requested to allocate / reserve RACH resources.

It can be understood that the first message may be a new message, such as a conditional handover request message, or reuse an existing message, such as a handover request message. The first message may include reservation indication information of random access channel resources. Optionally, the first message may also include the context information of the UE. For example, the context information of the UE includes radio resource management configuration (radio resource management-config, RRM-config), UE wireless access capability information, security parameters, radio bearer configuration, and system information block of the source cell (system information block 1 , SIB1).

For example, the measurement report includes the cell ID of cell1 / cell2 / cell3 / cell4 / cell5 (the cell ID may be a physical cell identifier (PCI) or CGI) and the cell signal quality of each cell, and the beam1 / under cell1 beam2 / beam3 beam identification, beam4 / beam5 beam identification under cell2, beam6 / beam7 beam identification under cell3, beam8 beam identification under cell4, beam9 beam identification under cell5, measurement report It may also include the signal quality of the beams of beam1-beam9. Suppose that the source network device determines the candidate target cell as cell1 / cell2 / cell3 / cell4 according to the measurement report, where cell1 and cell2 and cell4 belong to candidate target network device A, and cell3 belongs to candidate target network device B.

According to the measurement report, the source network device sends the first message to the candidate target network device. The first message may be network device granularity or cell granularity. Taking the source network device sending the first message to the candidate target network device A as an example, if the first message is of network device granularity, the source network device sends a first message to the candidate target network device A, and the first message includes all The cell identifier of the candidate target cell belonging to the candidate target network device A, for example, the first message includes the cell identifiers of the candidate target cell cell1, the candidate target cell cell2 and the candidate target cell cell4; if the first message is of cell granularity, the source The network device sends three first messages to the candidate target network device A. Each first message includes a cell ID of the candidate target cell belonging to the candidate target network device A. For example, a first message includes the cell ID of cell1 and one The first message includes the cell ID of cell2, and the first message includes the cell ID of cell4. It can be understood that the way in which the source network device sends the first message to other candidate target network devices is similar to the way in which the first message is sent to the candidate target network device A.

Optionally, the reservation indication information may be used to indicate one or more of the following information: reserved dedicated RACH resources; not reserved dedicated RACH resources but reserved public RACH resources; not reserved dedicated RACH resources and not reserved Public RACH resources. It should be noted that the reservation indication information may indicate any one of the above-mentioned information, and the following description takes the instruction to reserve the dedicated RACH resource as an example. The reservation indication information may be network device granularity, cell granularity, or beam granularity.

In implementation A1, the first message is of network device granularity. In addition to the reservation indication information, the first message also includes the identity of the candidate target cell and the identity of the beam belonging to the candidate target cell. In the case where the first message is the granularity of the network device, the reservation indication information may further include implementation modes B1 to B3:

Implementation method B1: The reservation indication information is granularity of the network equipment. That is, the reservation indication information is applicable to each candidate target cell belonging to the first candidate target network device indicated by the first message, where the first candidate target network device is one of a plurality of candidate target network devices. In this implementation manner, the first message includes: a reservation indication information, cell identifiers of all candidate target cells belonging to the first candidate target network device, and the candidate target cells belonging to the first candidate target network device The beam identifier of the second beam. The reservation indication information is used to indicate whether to reserve a dedicated RACH resource associated with the second beam of each candidate target cell. It should be noted that the second beam refers to a beam belonging to the candidate target cell included in the measurement report, and the beam identifier includes SSB index or CSI-RS index. Wherein, the reservation indication information may be a binary value (for example, "0" means no dedicated RACH resource is reserved, "1" means reserved dedicated RACH resource), or a Boolean value (for example, "False" means no reservation Dedicated RACH resources, "True" means reserved dedicated RACH resources) or other forms, this embodiment is not limited to this. In this implementation manner, the first message includes reservation indication information, and after receiving the reservation indication information, the first candidate target network device reserves each of the plurality of candidate target cells included in the first message The dedicated RACH resource associated with the second beam of the candidate target cell. For each beam of each candidate target cell belonging to the first candidate target network device included in the first message, indicating whether to reserve a dedicated RACH resource associated therewith can save signaling overhead.

Take the source network device sending the first message to the candidate target network device A as an example. Assuming that the first message is of network device granularity and the reservation indication information is of network device granularity, the first message carries a piece of reservation indication information. In addition to the cell IDs of cell1, cell2, and cell4, the first message also includes the beam ID of the second beam of cell1, for example, the beam ID including beam1, beam2, and beam3; For example, the beam identifiers of beam 4 and beam 5 are included; and the beam identifier of the second beam of cell 4 is also included, for example, the beam identifier of beam 8 is included. After the candidate target network device A receives the first message, assuming that the reservation indication information indicates that the second beam for cell1, cell2, and cell4 reserves the dedicated RACH resource associated with it, the candidate target network device A is beam1, beam2, Beam3, beam4, beam5 and beam8 reserve dedicated RACH resources associated with them. For example, the format of the content included in the first message may be as shown in Table 1 below:

Table 1

Implementation method B2: The reservation indication information is of cell granularity. In this implementation manner, the first message includes: the determined cell identifier of at least one candidate target cell belonging to the first candidate target network device, and the beam identifier of the third beam of each candidate target cell in the at least one candidate target cell And reservation indication information corresponding to each candidate target cell in at least one candidate target cell, the number of the reservation indication information is equal to the number of candidate target cells included in the at least one candidate target cell. For each candidate target cell in the first message, a reservation indication information is included to indicate whether to reserve a reserved dedicated RACH resource associated with the third beam of the cell. It should be noted that the third beam refers to a beam belonging to the candidate target cell included in the measurement report, and the beam identifier includes SSB index or CSI-RS index. Then, after receiving the reservation indication information, the first candidate target network device reserves the dedicated RACH resource associated with the third beam. For the beam of a candidate target cell belonging to the first candidate target network device included in the first message, indicating whether to reserve a dedicated RACH resource associated therewith can save signaling overhead.

Taking the source network device sending the first message to the candidate target network device A as an example, if the first message is of network device granularity and the reservation indication information is of cell granularity, it is assumed that the source network device requests the candidate target network device A to be cell1 respectively , The third beam of cell2 and cell4 reserves the dedicated RACH resource associated with it, then the first message carries three reservation indication information, corresponding to cell1, cell2 and cell4, respectively. In addition to the cell identifiers of cell1, cell2, and cell4, the first message also includes the beam identifier of the third beam of cell1, for example, the beam identifier of beam1, beam2, and beam3; and the beam identifier of the third beam of cell2, for example , Contains the beam identifiers of beam4 and beam5, and also contains the beam identifier of the third beam of cell4, for example, contains the beam identifier of beam8. The reservation indication information corresponding to cell1 contained in the first message indicates that the candidate target network device A respectively reserves dedicated RACH resources associated with beam1-3 of cell1; the reservation indication information corresponding to cell2 contained in the first message indicates the candidate target The network device A reserves dedicated RACH resources associated with beam 4-5 of cell 2 respectively; the reservation indication information corresponding to cell 4 contained in the first message instructs candidate target network device A to reserve dedicated RACH resources associated with beam 8 of cell 4. After receiving the first message, the candidate target network device A separately reserves the dedicated RACH resources associated with the third beams belonging to cell1, cell2, and cell4, that is, the dedicated RACH resources associated with beam1-5 and beam8, respectively. For example, the format of the content included in the first message may be as shown in Table 2 below:

Table 2

If the source network device requests the candidate target network device A to reserve dedicated RACH resources associated with the third beams of cell1 and cell4, respectively, but does not need to reserve for the third beam of cell2, the first message includes cell1 and cell4 The cell ID of the cell also includes the beam ID of the third beam of cell1 and cell4, for example, the beam IDs of beam1, beam2, and beam3 of cell1, and the beam ID of beam8 of cell4. The reservation indication information corresponding to cell1 included in the first message indicates that the candidate target network device A separately reserves dedicated RACH resources associated with beam1-3 of cell1; the reservation indication information corresponding to cell4 included in the first message indicates the candidate target Network device A reserves dedicated RACH resources associated with beam8 of cell4. After receiving the first message, the candidate target network device A separately reserves the dedicated RACH resources associated with the third beams belonging to cell1 and cell4, that is, the dedicated RACH resources associated with beam1-3 and beam8, respectively. For example, the format of the content included in the first message may be as shown in Table 3 below:

table 3

Implementation method B3: The reservation indication information is of beam granularity. The first candidate target network device includes at least one candidate target cell, and the candidate target cell may include at least one fourth beam. In this implementation, the first message includes: a beam identifier of at least one fourth beam, a cell identifier of a candidate target cell to which the at least one fourth beam belongs, and a reservation corresponding to each beam in the at least one fourth beam Indication information, the number of the reservation indication information is equal to the number of beams included in the at least one fourth beam, and the candidate target cell to which the at least one fourth beam belongs belongs to the first candidate target network device. For each beam included in the first message, reservation indication information is used to indicate whether a dedicated RACH resource associated with the fourth beam is reserved. It should be noted that the fourth beam refers to the beam included in the measurement report, and the beam identifier includes SSB index or CSI-RS index. In this implementation manner, the first message contains reservation indication information corresponding to the fourth beam of a candidate target cell, and then the first candidate target network device to which the candidate target cell belongs receives the reservation indication information, The dedicated RACH resource associated with the fourth beam is reserved.

Taking the request between the source network device and the candidate target network device A as an example, if the first message is of network device granularity and the reservation indication information is of beam granularity. If the source network device requests the candidate target network device A to reserve dedicated RACH resources for beam1-2 of cell1 and beam4 of cell2, the first message includes three reservation indication information, corresponding to beam1, beam2, and beam4, respectively. The first message includes the cell IDs of cell1 and cell2, and also includes the beam IDs of beam1 and beam2 of cell1, and also contains the beam IDs of beam2 of cell2. The reservation indication information corresponding to beam1 included in the first message indicates that candidate target network device A reserves the dedicated RACH resource associated with beam1 of cell1; the reservation indication information corresponding to beam2 included in the first message indicates candidate target network device A Reserve dedicated RACH resources associated with beam2 of cell1; the reservation indication information corresponding to beam4 included in the first message instructs candidate target network device A to reserve dedicated RACH resources associated with beam4 of cell2. After receiving the first message, the candidate target network device A reserves dedicated RACH resources associated with beam1, beam2, and beam4, respectively. For example, the format of the content included in the first message may be as shown in Table 4 below:

Table 4

In implementation A2, the first message is of cell granularity. The first candidate target network device includes at least one candidate target cell. The first message is used to request to reserve a RACH resource associated with a beam of a candidate target cell under the candidate target network device. It can be understood that, for multiple candidate target cells in the first candidate target network device, multiple first messages are sent, and the number of first messages is the same as the number of cells included in the multiple candidate target cells. The first message includes the identity of the candidate target cell and the identity of the beam belonging to the candidate target cell. In the case where the first message is the cell granularity, the reservation indication information includes implementation modes C1 and C2:

Implementation method C1: The reservation indication information is of cell granularity. In this implementation manner, the first message includes: the cell identifier of the third candidate target cell belonging to the first candidate target network device, the beam identifier of the fifth beam belonging to the third candidate target cell, and one reservation indication information. That is, the reservation indication information is used to instruct the first candidate target network device to reserve a dedicated RACH resource associated with the fifth candidate target cell's fifth beam. It should be noted that in this implementation, the first message corresponds to the third candidate target cell, the source network device sends the first message to the first candidate target network device, and the fifth beam refers to the information included in the measurement report. Beams belonging to the third candidate target cell, the beam identifier includes SSB index or CSI-RS index. In this implementation manner, the first message includes one of the reservation indication information, and after receiving the reservation indication information, the first candidate network device reserves the fifth beam associated with the third candidate target cell. Dedicated RACH resources.

Taking the source network device sending the first message to the candidate target network device A as an example, the first message is of cell granularity, and the reservation indication information is of cell granularity. If the source network device requests the candidate target network device A to reserve dedicated RACH resources associated with the beams of cell1 and cell2, the source network device sends two first messages to the candidate target network device A. Among them, in addition to the cell identifier of cell1 and a reservation indication information, a first message also includes the beam identifier of the fifth beam of cell1, for example, the beam identifiers of beam1, beam2, and beam3. The reservation indication information contained in the first message instructs the candidate target network device A to separately reserve dedicated RACH resources associated with beam1-3 of cell1; in addition to the cell ID of cell2 and a reservation indication information in another first message , Which also contains the beam identifier of the fifth beam of cell2, for example, the beam identifiers of beam4 and beam5, and the reservation indication information included in the first message indicates that the candidate target network device A reserves the beam4-5 associated with cell2, respectively. Dedicated RACH resources. After receiving these two first messages, the candidate target network device A reserves the dedicated RACH resources associated with the beam1-3 of cell1 and the beam4-5 of cell2, respectively. For example, the format of the content included in the two first messages may be as shown in Table 5 and Table 6 respectively:

table 5

Table 6

Implementation method C2: The reservation indication information is of beam granularity. In this implementation manner, the first message includes: the beam identifier of at least one sixth beam, the cell identifier of the fourth candidate target cell to which the at least one sixth beam belongs, and the corresponding to each beam in the at least one sixth beam Reservation indication information, the number of the reservation indication information is equal to the number of beams included in at least one sixth beam, and the fourth candidate target cell belongs to the first candidate target network device. It should be noted that in this implementation, the first message corresponds to the fourth candidate target cell, and the source network device sends the first message to the first candidate target network device. The sixth beam refers to the information included in the measurement report. Beams belonging to the fourth candidate target cell, the beam identifier includes SSB index or CSI-RS index. For at least one sixth beam belonging to the fourth candidate target cell included in the first message, the first message includes reservation indication information corresponding to each beam in the at least one sixth beam. In this implementation manner, the first message includes reservation indication information corresponding to each sixth beam in at least one sixth beam, and after the candidate target network device receives the reservation indication information corresponding to the sixth beam, The dedicated RACH resource associated with the sixth beam is reserved.

Taking the source network device sending the first message to the candidate target network device A as an example, the first message is of cell granularity, and the reservation indication information is of beam granularity. If the source network device requests the candidate target network device A to reserve dedicated RACH resources associated with beam1 and beam2 of cell1, and beam4 of cell2, respectively, the source network device sends two first messages to the candidate target network device A, one of which is the first In addition to the cell ID of cell1, a message also contains the beam IDs of beam1 and beam2 of cell1. The first message contains two reservation indication information, and one reservation indication information indicates that candidate target network device A reserves The dedicated RACH resource associated with beam1, another reservation indication information instructs candidate target network device A to reserve the dedicated RACH resource associated with beam2 of cell1; the source network device sends another first message to the candidate target network device A in addition to The cell identifier of cell2 also includes the beam identifier of beam4 of cell2, and the first message includes reservation indication information indicating that candidate target network device A reserves the dedicated RACH resource associated with beam4 of cell2. After receiving these two first messages, candidate target network device A reserves dedicated RACH resources associated with beam1 and beam2 of cell1 and beam4 of cell2, respectively. For example, the format of the content included in these two first messages may be as shown in Table 7 and Table 8 respectively:

Table 7

Table 8

When the reservation indication information is used to indicate that public RACH resources are reserved or not to reserve any RACH resources, it is similar to the manner in which the reservation indication information is used to indicate the reservation of dedicated RACH resources. The difference is that when the reservation indication information is used to indicate the reservation of a common RACH resource, if the reservation indication information is of network device granularity or cell granularity, the first message may include the reservation indication information and the cell identification of the candidate target cell , But does not include the beam identification; if the reservation indication information is of beam granularity, the first message may include the reservation indication information, the cell identification of the candidate target cell, and the beam identification.

Optionally, in yet another implementation manner, the reservation indication information may include a signal threshold: a signal quality threshold of a cell and / or a signal quality threshold of a beam. The first message further includes the identification of the candidate target cell, the measurement result of the corresponding candidate target cell, the identification of the beam belonging to the candidate target cell, and the measurement result of the corresponding beam. Then the method further includes the following steps:

The reservation indication information includes the signal quality threshold value of the cell. When the signal quality of the first candidate target cell is greater than or equal to the signal quality threshold value of the cell, the Describe dedicated RACH resources for all beams of the first candidate target cell; or,

The reservation indication information includes the signal quality threshold of the cell and the signal quality threshold of the beam, when the signal quality of the second candidate target cell is greater than or equal to the signal quality threshold of the cell, and the second candidate target When the signal quality of at least one beam of the cell is greater than or equal to the signal quality threshold of the beam, dedicated RACH resources are reserved for the at least one beam.

It should be noted that the first candidate target cell and the second candidate target cell here may be any of the candidate target cells indicated in the first message.

In a specific implementation, the first message includes at least one of the identifier of the candidate target cell, the signal quality of the candidate target cell, the identifier of the beam under the candidate target cell, and the signal quality of the beam. The RACH resource reservation indication information optionally includes a cell-level signal quality threshold X and / or a beam-level signal quality threshold Y. If the RACH resource reservation indication information includes a cell-level signal quality threshold X, the first candidate target network device may be a candidate target cell whose signal quality of the cell in the first message is higher than or equal to X The next beam (that is, all beams belonging to the candidate target cell included in the first message) is allocated with a dedicated RACH resource associated with it; if the reservation indication information of the RACH resource includes the cell-level signal quality threshold X and If the beam-level signal quality threshold value is Y, the candidate target network device is a beam whose signal quality of the beam under the candidate target cell whose cell quality in the first message is higher than or equal to X is higher than or equal to Y (ie At least one beam included in the first message that satisfies these conditions) allocates a dedicated RACH resource associated therewith. If the reservation indication information includes the beam-level signal quality threshold Y, the candidate target network device may allocate a beam associated with the beam whose signal quality is higher than or equal to Y to the beam contained in the first message. Dedicated RACH resources.

In this implementation, the source network device sends the signal quality threshold of the cell and / or the signal quality threshold of the beam to the candidate target network device. The candidate target network device uses the signal quality of the candidate target cell and the beam under the candidate target cell The signal quality of the system determines which dedicated RACH resources are reserved for which beams in which cells. This method improves the autonomy of the candidate target network device and improves the accuracy of decision-making to a certain extent.

S102. The candidate target network device sends indication information that triggers a switching condition and a random access channel resource to the source network device. The indication information of the random access channel resource is used to indicate a reservation result of the random access channel resource. .

Correspondingly, the source network device receives the indication information for triggering the handover condition and the random access channel resource sent by the candidate target network device.

After receiving the first message, the candidate target network device prepares for handover. The candidate target network device performs allocation / reservation of dedicated RACH resources and / or public RACH resources according to the reservation instruction information. That is, the candidate target network device may allocate / reserve dedicated RACH resources and / or public RACH resources according to the reservation indication information, or the signal quality threshold of the cell and / or the signal quality threshold of the beam.

The candidate target network device RACH resource reservation results include: 1) the candidate target network device receives the UE context information provided by the source network device, and allocates dedicated RACH resources for the UE; or 2) the candidate target network device receives the UE provided by the source network device Context information, which allocates common RACH resources for the UE; or 3) The source network device does not notify the candidate target network device of the UE's context information in advance. Obviously, the candidate target network device does not allocate dedicated or public RACH resources for the UE.

The candidate target network device sends indication information to trigger the handover condition and the RACH resource to the source network device. The triggering handover condition includes a signal quality threshold for cell handover. The indication information of the random access channel resource is used to indicate the reservation result of the random access channel resource. Specifically, the indication information of the random access channel resource is used to indicate one or more of the following information: the dedicated random access channel resource is reserved; the dedicated random access channel resource is not reserved but the public random access channel is reserved Resources; dedicated random access channel resources are not reserved and common random access channel resources are not reserved. The trigger switching condition and the indication information of the RACH resource may be carried in the request confirmation message. The request confirmation message may be a new message, such as a conditional handover request confirmation message, or reuse an existing message, such as a handover request confirmation message.

Optionally, when the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is reserved, the method further includes: sending the dedicated random access channel resource information to the source network device . The dedicated RACH resource information may be included in the above-mentioned reply request confirmation message.

Optionally, when the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is not reserved but the common random access channel resource is reserved, the method further includes: The network device sends common random access channel resource information.

S103. The source network device sends a second message to the terminal device, where the second message includes the trigger switching condition and the indication information of the random access channel resource.

Correspondingly, the terminal device receives the second message.

In a possible manner, after receiving the trigger switching condition and the indication information of the random access channel resource sent by the candidate target network device, the source network device transparently transmits the trigger switching condition and the random access The indication information of the incoming channel resource is delivered to the terminal device.

Specifically, the source network device sends a second message to the terminal device. The second message may be a new RRC message, for example, a conditional handover message or an RRC reconfiguration message including conditional handover configuration information; or reuse an existing RRC message For example, the RRC reconfiguration message carrying the ReconfigurationWithSync cell or the RRC connection reconfiguration message carrying the mobility control information cell (mobility control information), or may have another name, which is not limited in this application. The second message includes indication information for triggering handover conditions and RACH resources. The trigger switching condition includes configuration information of the condition that triggers the real switching. For example, taking the A3 event as an example, when the signal quality of the candidate target cell is higher than the offset value of the signal quality of the serving cell by a certain amount, the conditions for true handover are satisfied, and the candidate target cell may be used as the target cell. In another example, taking the A5 event as an example, when the signal quality of the candidate target cell is higher than threshold 1 and the signal quality of the serving cell is lower than threshold 2, the conditions for true handover are satisfied, and the candidate target cell may be used as the target cell.

Optionally, the second message may further include dedicated random access channel resources (for example, contention free random access (CFRA) resources) information, and the dedicated random access channel resources include a preamble (preamble) index and first time-frequency resource; and / or the second message may further include common random access channel resource information, the common random access channel resource includes second time-frequency resource; and the second The message may also include the identification of one or more candidate target cells, the identification of one or more beams under the candidate target cell (for example, SSB index or CSI-RS index); and the second message may also include the beam signal threshold . Wherein, the dedicated / public random access channel resource information may be the resource itself, or the index or number of the resource or other forms, and there is a corresponding relationship between the index or number of the resource and the resource. Optionally, the beam signal threshold may also be sent by the source network device to the terminal device in other messages, or it is predefined by the protocol, which is not limited herein.

In this embodiment, the indication information of the random access channel resource clearly indicates the reservation result of the random access channel resource. In another embodiment, the indication information of the random access channel resource is optional, and may be indirectly or implicitly through dedicated random access channel resource information or public random access channel resource information included in the second message Indicates the reservation result of random access channel resources. That is, when the dedicated random access channel resource information is included in the second message, it indicates that the reservation result of the random access channel resource is that the dedicated random access channel resource is reserved for the terminal device; when the second message includes the common random access channel resource When entering the channel resource information, it indicates that the reservation result of the random access channel resource is that the dedicated random access channel resource is not reserved but the common random access channel resource is reserved; when the second message does not include the dedicated random access When the channel resource information does not include the common random access channel resource information, it indicates that the reservation result of the random access channel resource is that the dedicated random access channel resource is not reserved and the common random access channel resource is not reserved.

S104. The terminal device determines a random access channel resource corresponding to a beam for random access according to the trigger switching condition and the indication information of the random access channel resource.

After receiving the second message, the terminal device determines whether the condition for triggering the handover is satisfied. For example, taking the A3 event as an example, when a candidate target cell satisfies the trigger switching condition (that is, the signal quality of the candidate target cell is higher than the signal quality of the serving cell by a certain offset value), the terminal device determines that the cell is the target cell.

There may be one or more candidate target cells that meet the trigger handover condition. The terminal device determines the target beam from the beams of the candidate target cell that meets the trigger handover condition according to the indication information of the random access channel resource, and then associates it with the target beam Is determined as the random access channel resource that initiates random access. The target beam belongs to a target cell, and the target cell is one of the candidate target cells that satisfy the condition for triggering handover.

A possible implementation manner is: in a cell that satisfies the trigger switching condition, determine the dedicated random access resource associated with the beam that reserves the dedicated random access channel resource and meets the beam measurement condition as the initiated random access Random access resource; where, when the signal quality of the beam is greater than or equal to the beam signal threshold, the beam is a beam that satisfies the beam measurement condition.

Optionally, if no dedicated random access channel resource is reserved in the cell that meets the condition for triggering handover and the beam measurement condition is satisfied, it can be determined that there is a common random access channel resource reserved and the beam is satisfied Measuring the beam of the condition, and determining the common random access resource as a random access channel resource that initiates random access;

Optionally, if no dedicated random access channel resource is reserved in the cell that satisfies the condition for triggering handover and the beam measurement condition is satisfied, and no common random access channel resource is reserved and the beam measurement is satisfied The conditional beam may obtain random access channel resources from system information broadcast by the network device to which the cell that meets the triggering handover condition belongs, and determine the acquired random access channel resources as random access to initiate random access Channel resources.

For example, the terminal device determines the candidate target cell cell1 that meets the triggering handover condition as the target cell (the network device to which the candidate target cell cell1 belongs is the target network device), and the terminal device is based on the beam under the target cell (ie, cell1) Measurement, it is determined that the beam whose signal quality is higher than or equal to the beam signal threshold and equipped with CFRA resources is the beam that the terminal device needs to monitor RAR, and the CFRA resource associated with the beam is the RACH resource that initiates random access. Specifically, for another example, the terminal device measures that the signal quality of SSB2 of cell1 is higher than the beam signal threshold, and SSB2 is equipped with CFRA resources (the second message includes CFRA resources associated with SSB2, for example, includes association with SSB2 The preamble index of preamble0 and the first time-frequency resource associated with SSB2), the terminal device determines the CFRA resource associated with SSB2 as the RACH resource that initiates random access, that is, the preamble0 associated with SSB2 and the first associated with SSB2 The time-frequency resource is determined as the RACH resource that initiates random access. The terminal device needs to monitor the RAR sent through SSB2.

It should be noted that when a random access channel resource that is reserved for a dedicated random access channel resource and meets beam measurement conditions is determined as a random access channel resource that initiates random access, the resource that initiates random access Then it is reserved dedicated random access channel resource; when no cell with dedicated random access channel resource and satisfying beam measurement condition is reserved in the cell that meets the condition for triggering handover, the resource that initiates random access is Common random access channel resources; if in the cell that meets the conditions for triggering handover, no dedicated random access channel resources are reserved and the beams satisfy the beam measurement conditions, and no common random access channel resources are reserved and When a beam that satisfies the beam measurement condition exists, the resource that initiates random access is the random access channel resource that the terminal device obtains from system information broadcast by the network device to which the cell that meets the trigger switching condition belongs.

S105. The terminal device initiates random access to the target network device according to the determined random access channel resource.

When the determined random access channel resource is a reserved dedicated random access channel resource, and the dedicated random access channel resource includes a preamble index and a first time-frequency resource, then the first time-frequency resource is directed to the target The network device sends a preamble; when the determined random access channel resource is a common random access channel resource, and the common random access channel resource includes the second time-frequency resource, the terminal device selects from a number of preambles defined in the protocol to the target network device The sent preamble sends the preamble to the target network device on the second time-frequency resource. Still taking the above example as an example, if the terminal device determines SSB2 as a beam satisfying the condition, and determines the preamble 0 associated with SSB2 and the first time-frequency resource associated with SSB2 as the resources for random access, the terminal device uses the The first time-frequency resource associated with SSB2 sends preamble0 to the target network device.

After receiving the preamble, the target network device sends a random access response (RAR) message to the terminal device. The random access response message includes an uplink transmission resource (UL) and a timing advance (TA) value. For example, the target network device receives the preamble 0 sent by the terminal device in the first time-frequency resource, and infers that the signal quality of the downlink beam SSB2 is good, and returns a RAR message to the terminal device through SSB2 (or in the beam direction of SSB2). The RAR message includes uplink transmission resources and timing advance values.

After receiving the RAR message, the terminal device sends a conditional switching / reconfiguration complete message to the target network device. For example, the terminal device monitors the RAR sent through SSB2. After receiving the RAR message sent by the target network device through SSB2, the terminal device uses the UL included in the RAR message to send an RRC message to the target network device to notify the target network device of the conditional switch / Reconfiguration is complete. The RRC message may be a new RRC message, or reuse an existing RRC message, such as an RRC reconfiguration completion message.

Through the above process, the random access process is completed, and the terminal device successfully switches to the target network device.

According to a communication method provided by an embodiment of the present application, the source network device reasonably requests the candidate target network device to reserve random access channel resources, thereby reducing waste of resources and improving the success rate of handover.

The above embodiment provides a method for the source network device to reasonably request the candidate target network device to reserve / allocate resources. The candidate target network device allocates resources according to the reservation indication information or the signal quality threshold provided by the source network device. For example, the candidate target network device allocates different CFRA resources to different beams under the same candidate target cell (different means that at least one of preamble and time-frequency resource is different).

Considering that the candidate target network device may allocate CFRA resources to many beams, resulting in lack or waste of CFRA resources. Based on the foregoing embodiments, this embodiment provides another method for the candidate target network device to allocate CFRA resources reasonably.

FIG. 3 is a schematic diagram of an interaction process of another communication method provided by an embodiment of the present application. among them:

S201. The source network device sends a first message to the candidate target network device, where the first message includes reservation indication information of random access channel resources.

This step is the same as S101 in the above embodiment, and will not be repeated here.

S202. The candidate target network device groups one or more beams under the candidate target cell included in the first message to obtain one or more beam groups. The beams in the beam group may belong to the same candidate target cell or belong to different candidate target cells.

S203. The candidate target network device separately reserves dedicated random access channel resources associated with the one or more beam groups.

The first message sent by the source network device to the candidate target network device includes the identification of one or more candidate target cells, and the first message includes the beam identification of one or more beams under the candidate target cell. The identification of the target cell and the beam identification of the beam are part or all of the measurement report reported by the terminal device to the source network device. For each candidate target cell belonging to the candidate target network device included in the first message, the candidate target network device groups the multiple beams belonging to the candidate target cell included in the first message, and assigns the associated Dedicated RACH resources, that is, multiple SSBs or multiple CSI-RSs under the same candidate target cell are associated with the same dedicated RACH resource. For example, the candidate target network device reserves the same CFRA resource for SSB1 and SSB2 under the candidate target cell cell1, and the same CFRA resource is associated with both SSB1 and SSB2 (for example, the CFRA resource includes preamble1 and time-frequency resource 1 , Then SSB1 is associated with preamble1 and time-frequency resource 1, and SSB2 is also associated with preamble1 and time-frequency resource 1). In addition, the same CFRA resource is reserved for SSB4 and SSB5 under the candidate target cell cell2. SSB4 is also associated with SSB5 (for example, if the CFRA resource includes preamble2 and time-frequency resource 2, SSB4 is associated with preamble2 and time-frequency resource 2, and SSB5 is also associated with preamble2 and time-frequency resource 2). The candidate target cell cell1 and the candidate target cell cell2 both belong to the candidate target network device. Here, the dedicated RACH resources reserved for different beam groups must be different, that is, the preamble and time-frequency resources associated with one beam group are different from the preamble and time-frequency resources associated with another beam group. In addition, the beam here refers to the downlink beam sent by the target network device. By reserving dedicated RACH resources for the beam group, resources can be saved and the utilization rate of RACH resources can be improved.

S204. The candidate target network device sends indication information that triggers a handover condition and a random access channel resource to the source network device. The indication information of the random access channel resource is used to indicate a reservation result of the random access channel resource. .

After receiving the first message, the candidate target network device prepares for handover. The candidate target network device reserves dedicated RACH resources and / or public RACH resources according to the reservation instruction information. That is, the candidate target network device may reserve dedicated RACH resources and / or public RACH resources according to the reservation indication information, or the signal quality threshold of the cell and / or the signal quality threshold of the beam.

Optionally, when the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is reserved, the method further includes: sending the dedicated random access channel resource information to the source network device , The dedicated random access channel resource is a dedicated random access channel resource associated with the beam group. The dedicated RACH resource may be included in the above-mentioned reply request confirmation message. The dedicated random access channel resource information may be the resource itself, or the index or number of the resource or other forms, and there is a corresponding relationship between the index or number of the resource and the resource.

S205. The source network device sends a second message to the terminal device, where the second message includes the trigger switching condition and the indication information of the random access channel resource.

Correspondingly, the terminal device receives the second message.

Optionally, the second message may further include dedicated random access channel resource information (for example, a contention-free random access resource), and the dedicated random access channel resource includes a preamble index and a first time-frequency resource, The dedicated random access channel resource is a dedicated random access channel resource associated with the beam group; and the second message may further include an identifier of one or more candidate target cells, and the candidate target cell includes the identifier in the beam group The identification of the beam of (for example, SSB index or CSI-RS index); and the second message may further include a beam signal threshold. It can be understood that the dedicated random access channel resource may be associated with one or more beam identifiers.

In the example described in S203, the candidate target network device reserves the same CFRA resource associated with SSB1 and SSB2 under the candidate target cell cell1 (if the CFRA resource includes preamble1 and time-frequency resource 1, SSB1 and preamble1 and Time-frequency resource 1 is associated, and SSB2 is also associated with preamble1 and time-frequency resource 1). In addition, reserve the same CFRA resource associated with SSB4 and SSB5 under the candidate target cell cell2 (if the CFRA resource includes preamble2 and time-frequency) Resource 2, SSB4 is associated with preamble2 and time-frequency resource 2, and SSB5 is also associated with preamble2 and time-frequency resource 2). The candidate target cell cell1 and the candidate target cell cell2 both belong to the candidate target network device. For convenience of subsequent description, SSB1 and SSB2 under cell1 are called beam group 1, and SSB4 and SSB5 under cell2 are called beam group 2. Then, the second message includes: the trigger switching condition, the indication information of the random access channel resource, the identifier of the candidate target cell cell1, the identifier of SSB1 under cell1, the identifier of SSB2, and beam group 1 (beam group 1 includes CFRA resources (eg, preamble1 and time-frequency resource 1) associated with SSB1 and SSB2), the identification of the candidate target cell cell2, the identification of SSB4 under cell2, and the identification of SSB5, and beam group 2 (beam group 2 includes SSB4 and SSB5 ) Associated CFRA resources (eg, preamble 2 and time-frequency resources 2), beam signal thresholds (eg, SSB-Threshold).

S206. The terminal device determines a random access channel resource that initiates random access according to the trigger switching condition and the indication information of the random access channel resource.

In the example described in S205, in a possible implementation manner, after receiving the second message, the terminal device determines the candidate target cell cell1 that meets the trigger switching condition as the target cell (the network device to which cell1 belongs is the target) Network equipment), the terminal equipment selects a beam with a signal quality higher than or equal to the beam signal threshold and equipped with CFRA resources as a beam for random access to the target cell based on the measurement of the beam under the target cell (ie, cell1). Specifically, for example, the terminal device measures that the signal quality of SSB2 of cell1 is higher than the beam signal threshold, and SSB2 is associated with CFRA resources (the second message includes the preamble index associated with SSB2, preamble1, and the time associated with SSB2. Frequency resource 1), the terminal device determines SSB2 as a satisfied beam, and determines preamble1 associated with SSB2 and time-frequency resource 1 associated with SSB2 as resources for initiating random access.

S207. The terminal device performs a random access process with the target network device according to the determined random access channel resource.

Since the candidate target network device reserves the dedicated RACH resource according to the beam group, that is, the dedicated RACH resource is associated with a beam group, the target network device receives the random access sent by the terminal device according to the determined dedicated RACH resource After the request message (such as a preamble), it is necessary to determine which beam in the beam group to send the RAR message. Specifically, there can be the following three D1 ~ D3 implementation methods:

Specifically, in the implementation manner D1, as shown in FIG. 4a, S207 includes:

S2071: The terminal device sends a third message to the target network device according to the dedicated random access channel resource associated with the beam group. Wherein the third message is used to initiate random access, the third message includes an identifier of the first beam, the first beam is a beam in the beam group that satisfies the beam measurement condition, and the first A beam is associated with the dedicated random access channel resource.

Correspondingly, the target network device receives the third message.

For example, as described in S206, the signal quality of SSB2 measured by the terminal device is higher than the threshold, and SSB2 is equipped with CFRA resources, which are associated with beam group 1, and the CFRA resources include preamble 1 and time-frequency resource 1, and SSB 2 belongs to beam group 1. , The terminal device sends preamble1 to the target network device on the time-frequency resource 1 associated with SSB2. At the same time as sending preamble1, the terminal device also sends the SSB index associated with the preamble1 to the target network device, that is, the identifier or index of SSB2 Send to the target network device.

S2072. The target network device sends a fourth message to the terminal device through the first beam. Wherein, the fourth message is a response message of the third message, and the fourth message includes TA value, uplink transmission resource information and the like.

Correspondingly, the terminal device receives the fourth message.

The terminal device carries the identifier of the first beam in the third message, then the target network device may specify which target beam meets the condition determined by the terminal device, so that the target network device passes the first beam or the first beam The corresponding downlink direction sends the fourth message. The first beam is a beam in the above beam group.

In the above example, after receiving the identifiers or indexes of preamble1 and SSB2 sent by the terminal device, the target network device infers that the signal quality of SSB2 is good, and returns a RAR message to the terminal device through SSB2 (or in the downstream direction corresponding to SSB2) . The RAR message includes uplink transmission resource UL, grant, TA value, etc.

S2073. The terminal device sends a fifth message to the target network device, where the fifth message is used to indicate the completion of the handover.

Correspondingly, the target network device receives the fifth message.

In the above example, after receiving the RAR message sent by the target network device via SSB2, the terminal device uses the UL included in the RAR message to send an RRC message to the target network device to notify the target network device that the conditional switching / reconfiguration is completed. The RRC message may be a new RRC message or reuse an existing RRC message, such as an RRC reconfiguration completion message.

In the implementation manner D2, as shown in FIG. 4b, S207 includes:

S2071 '. The terminal device sends a sixth message to the target network device according to the dedicated random access channel resource associated with the beam group. Wherein, the sixth message is used to initiate random access.

Correspondingly, the target network device receives the sixth message.

For example, as described in S206, the signal quality of the SSB2 measured by the terminal device is higher than the threshold, and the SSB2 is equipped with a CFRA resource, which is associated with the beam group 1, and the CFRA resource includes preamble 1 and time-frequency resource 1, and SSB 2 belongs to the beam group 1. , The terminal device sends preamble1 to the target network device on the time-frequency resource 1 associated with SSB2.

S2072 ': The target network device sends a seventh message to the terminal device through each beam included in the beam group. Each seventh message is a response message of the sixth message, and each seventh message includes different uplink transmission resource information.

Correspondingly, the terminal device receives the seventh message.

Since the sixth message sent by the terminal device does not carry the identifier of the first beam, and for the received preamble sent by the terminal device and the time-frequency resources used to send the preamble, the target network device pre-allocates the Each beam is assigned the same preamble and time-frequency resources, so the target network device does not know which beam the terminal device determines meets the condition. The target network device sends a RAR message to the terminal device through each beam in the beam group associated with the preamble and the time-frequency resource, and each RAR message includes a different UL grant. The RAR message may also include the TA value.

In the above example, after the target network device receives preamble1 sent by the terminal device, since the beams in beam group 1, namely SSB1 and SSB2, are associated with preamble1 and time-frequency resource 1, the target network device passes beam group 1 Each beam included separately sends RAR to the terminal device, that is, the target network device replies to the terminal device with a RAR1 message through SSB1 (or in the downlink beam direction of SSB1), and RAR1 includes uplink transmission resources UL grant1, TA1, etc .; And the target network device returns a RAR2 message to the terminal device through SSB2 (or in the downlink beam direction of SSB2), and RAR2 includes uplink transmission resources UL grant2, TA2, and so on. The UL grant1 and UL grant2 included in RAR1 and RAR2 are different, and TA1 and TA2 may be the same or different.

S2073 ': The terminal device sends an eighth message to the target network device on the uplink transmission resource included in the received seventh message. Wherein, the eighth message is used to indicate the completion of the handover.

Correspondingly, the candidate target network device receives the eighth message.

The method further includes the following step: the target network device determines a beam to communicate with the terminal device according to the uplink transmission resource at which the terminal device sends the eighth message.

Because the target network device sends the RAR containing UL grant to the terminal device through each beam included in the beam group respectively, there is a correspondence between the beam and the UL grant, and the target network device according to the UL used by the terminal device to send the eighth message , Knowing which beam the UL grant corresponds to, so as to determine the beam as a beam that communicates with the terminal device, and perform subsequent communication with the terminal device on the beam.

In the above example, the terminal device sends preamble1 to the target network device on the time-frequency resource 1 associated with SSB2. After receiving the preamble1, the target network device replies to the terminal device with a RAR1 message through SSB1. RAR1 includes the uplink transmission resource UL grant1, And the target network device replies to the terminal device with a RAR2 message through SSB2, and RAR2 contains the uplink transmission resource UL grant2. The terminal device receives RAR2 in the downlink beam direction of SSB2, and uses the UL2 grant included in RAR2 to send an RRC message to the target network device to notify the target network device that the condition switching / reconfiguration is completed. The RRC message may be a new RRC message or reuse an existing one RRC message, such as RRC reconfiguration complete message. Due to the difference between UL grant1 and UL grant2, the target network device can push out the beam that meets the condition determined by the terminal device according to the uplink transmission resource used by the terminal device to send the RRC message (that is, UL grant2) (because RAR2 contains UL grant2, and When the target network device replies to the RAR2 message through SSB2, the target network device infers that the beam determined by the terminal device to satisfy the condition is SSB2).

In the implementation manner D3, as shown in FIG. 4c, S207 includes:

S2071 ”. The terminal device sends a ninth message to the target network device according to the dedicated random access channel resource associated with the beam group. The ninth message is used to initiate random access.

Correspondingly, the target network device receives the ninth message.

S2072 ". The target network device sends a tenth message to the terminal device through each beam included in the beam group. Each tenth message is a response message to the ninth message. Ten messages include the same uplink transmission resource information.

Correspondingly, the terminal device receives the tenth message.

Since the ninth message sent by the terminal device does not carry the identifier of the first beam, and for the received preamble sent by the terminal device and the time-frequency resources used to send the preamble, the target network device pre-allocates the Each beam is assigned the same preamble and time-frequency resources, so the target network device does not know which beam the terminal device determines meets the condition. The target network device sends a RAR message to the terminal device through each beam in the beam group associated with the preamble and the time-frequency resource, and each RAR message includes the same UL grant. The RAR message may also include the TA value.

In the above example, after the target network device receives preamble1 sent by the terminal device, since the beams in beam group 1, namely SSB1 and SSB2, are associated with preamble1 and time-frequency resource 1, the target network device passes beam group 1 Each beam included separately sends RAR to the terminal device, that is, the target network device replies to the terminal device with a RAR1 message through SSB1 (or in the downlink beam direction of SSB1), and RAR1 includes uplink transmission resources UL grant1, TA1, etc .; And the target network device returns a RAR2 message to the terminal device through SSB2 (or in the downlink beam direction of SSB2), and RAR2 includes uplink transmission resources UL grant1, TA2, and so on. RAR1 and RAR2 contain the same UL grant1, and TA1 and TA2 may be the same or different.

S2073 ". The target network device receives the eleventh message sent by the terminal device in the uplink transmission resource. The eleventh message is used to indicate the completion of handover, and the eleventh message includes the The identification of a beam.

Correspondingly, the target network device receives the eleventh message.

Unlike the above implementation D2, the UL included in the tenth message is the same. The target network device cannot determine which beam is satisfied by the terminal device according to the UL grant used by the terminal device to send the eleventh message, so , The terminal device includes the identifier of the first beam in the eleventh message, so that the target network device can know that the target beam determined by the terminal device is the first beam according to the identifier of the first beam, and the first beam Communicate with terminal equipment.

In the above example, the terminal device receives the RAR2 sent by the target network device through SSB2, and uses the UL1 grant1 contained in RAR2 to send an RRC message to the target network device to notify the target network device that the conditional switching / reconfiguration is complete. The RRC message may be new RRC message or reuse existing RRC message, such as RRC reconfiguration complete message. Since RAR1 and RAR2 both contain UL grant1, the RRC message sent by the terminal device contains the identifier (SSB index or CSI-RS index) of the beam it determines to perform random access with the target cell, such as the identifier or index of SSB2. The target network device may determine the beam to communicate with the terminal device according to the beam identifier.

According to a communication method provided by an embodiment of the present application, the source network device reasonably requests the candidate target network device to reserve random access channel resources, thereby reducing waste of resources and improving the success rate of handover; and the candidate target network device The beams of the target cell are grouped, and the random access channel resources are reserved in groups, which can improve the resource utilization.

The method of the embodiment of the present invention is described in detail above, and the device of the embodiment of the present invention is provided below.

Based on the same concept of the communication method in the above embodiment, as shown in FIG. 5, an embodiment of the present application further provides a communication device 1000, which can be applied to the above-mentioned communication methods shown in FIGS. 2 to 3. The communication device 1000 may be the terminal device 200 shown in FIG. 1, or may be a component (for example, a chip) applied to the terminal device 200. The communication device 1000 includes a transceiver unit 11 and a processing unit 12. among them:

The transceiver unit 11 is configured to receive a first message from a source network device, where the first message includes: trigger switching conditions and indication information of random access channel resources;

The processing unit 12 is configured to determine a random access channel resource that initiates random access according to the trigger switching condition and the indication information of the random access channel resource;

The transceiver unit 11 is further configured to initiate random access to the target network device according to the determined random access channel resource.

In an implementation manner, the first message further includes a beam signal threshold; the processing unit 12 is configured to reserve dedicated random access channel resources and satisfy beam measurement in a cell that meets the trigger switching condition The random access channel resource associated with the conditional beam is determined to be the random access channel resource that initiates random access; wherein, when the signal quality of the beam is greater than or equal to the beam signal threshold, the beam is to satisfy the beam Measuring condition beam.

In another implementation manner, the processing unit 12 is configured to determine that there is a reservation if no dedicated random access channel resource is reserved in the cell that meets the condition for triggering handover and the beam measurement condition is satisfied. A common random access channel resource and a beam that satisfies the beam measurement condition, the common random access channel resource is determined as a random access channel resource that initiates random access; or if in the cell that meets the condition for triggering handover, The beams that do not reserve dedicated random access channel resources and meet beam measurement conditions and that do not reserve public random access channel resources and meet beam measurement conditions are obtained from system information broadcast by the network device to which the beam belongs The random access channel resource determines the acquired random access channel resource as the random access channel resource that initiates random access.

In yet another implementation manner, the dedicated random access channel resource is a dedicated random access channel resource associated with the beam group, and the transceiver unit 11 is configured to use the dedicated random access channel resource associated with the beam group , Sending a third message to the target network device, where the third message is used to initiate random access, the third message includes an identifier of the first beam, and the first beam belongs to the beam group that satisfies the beam measurement A beam of conditions; receiving a fourth message from the target network device through the first beam, the fourth message is a response message of the third message, the third message includes uplink transmission resource information; and Sending a fifth message to the target network device on the uplink transmission resource, where the fifth message is used to indicate that the handover is completed.

More detailed descriptions of the above-mentioned transceiver unit 11 and processing unit 12 can be directly obtained by directly referring to the relevant description of the terminal device in the method embodiments shown in FIG. 2 to FIG. 3, and no further details are provided here.

Based on the same concept of the communication method in the above embodiment, as shown in FIG. 6, an embodiment of the present application further provides a communication device 2000, which can be applied to the above communication methods shown in FIGS. 2 to 3. The communication device 2000 may be the network device 100 shown in FIG. 1, or may be a component (for example, a chip) applied to the network device 100. The communication device 2000 includes a sending unit 21 and a receiving unit 22. among them:

The sending unit 21 is configured to send a first message to a candidate target network device, where the first message includes reservation indication information of random access channel resources;

The receiving unit 22 is configured to receive trigger switching conditions and indication information of random access channel resources sent by the candidate target network device, and the indication information of the random access channel resources is used to indicate a pre-random access channel resource Leave the result

The sending unit 21 is further configured to send a second message to the terminal device, where the second message includes the trigger switching condition and the indication information of the random access channel resource.

Optionally, the sending unit 21 and the receiving unit 22 may be independent units, or may be a whole transceiver unit.

More detailed descriptions of the sending unit 21 and the receiving unit 22 can be directly obtained by directly referring to the relevant description of the source network device in the method embodiments shown in FIG. 2 to FIG. 3, and details are not described here.

Based on the same concept of the communication method in the above embodiment, as shown in FIG. 7, an embodiment of the present application further provides a communication device 3000, which can be applied to the above-mentioned communication methods shown in FIGS. 2 to 3. The communication device 3000 may be the network device 100 shown in FIG. 1, or may be a component (for example, a chip) applied to the network device 100. The communication device 3000 includes a transceiver unit 31 and a processing unit 32. The transceiver unit 31 may be an independent unit, or may be a whole transceiver unit. among them:

The transceiver unit 31 is configured to receive a first message from a source network device, where the first message includes random access channel resource reservation indication information;

The transceiving unit 31 is further configured to send to the source network device indication information that triggers switching conditions and random access channel resources, and the indication information of the random access channel resources is used to indicate the reservation of random access channel resources result.

In an implementation manner, the reservation indication information includes a signal quality threshold value of a cell and / or a signal quality threshold value of a beam; the first message further includes an identifier of a candidate target cell, and a measurement result of the corresponding candidate target cell , The identification of the beam belonging to the candidate target cell and the measurement result of the corresponding beam;

The processing unit 32 is used for the reservation indication information to include a signal quality threshold value of a cell. When the signal quality of the first candidate target cell is greater than or equal to the signal quality threshold value of the cell, the All beams belonging to the first candidate target cell indicated in a message reserve dedicated random access channel resources;

The processing unit 32 is used for the reservation indication information to include the signal quality threshold of the cell and the signal quality threshold of the beam, when the signal quality of the second candidate target cell is greater than or equal to the signal quality threshold of the cell , And when the signal quality of at least one beam of the candidate target cell is greater than or equal to the signal quality threshold of the beam, dedicated random access channel resources are reserved for the at least one beam.

In yet another implementation, when the indication information of the random access channel resource is used to indicate that a dedicated random access channel resource is reserved, the transceiver unit 31 is also used to send a dedicated message to the source network device Random access channel resource information;

When the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is not reserved but the common random access channel resource is reserved, the transceiver unit 31 is also used to send to the source network device Common random access channel resource information.

In yet another implementation, the processing unit 32 is further configured to group one or more beams under the candidate target cell to obtain one or more beam groups; and assign the one or more beam groups respectively Corresponding dedicated random access channel resources.

In yet another implementation, the transceiver unit 31 is configured to receive a third message sent by a terminal device on a dedicated random access channel resource associated with the beam group, and the third message is used to initiate random access. , The third message includes the identifier of the first beam, the first beam is a beam in the beam group that satisfies the beam measurement condition; the transceiver unit 31 is configured to use the first beam to The terminal device sends a fourth message, the fourth message is a response message of the third message, the fourth message includes uplink transmission resource information; and the transceiver unit 31 is also used to receive from the terminal device A fifth message sent using the uplink transmission resource, where the fifth message is used to indicate the completion of the handover.

In yet another implementation manner, the transceiver unit 31 is configured to receive a sixth message sent by the terminal device according to a dedicated random access channel resource associated with the beam group, and the sixth message is used to initiate random access; The transceiver unit 31 is configured to send a seventh message to the terminal device through each beam included in the beam group, each seventh message is a response message of the sixth message, and each seventh message The included uplink transmission resources are different; and the transceiver unit 31 is further configured to receive an eighth message sent by the terminal device on the received uplink transmission resource included in one of the seventh messages, and the eighth message is used to Indicating that the handover is completed; the processing unit 32 is further configured to determine a downlink beam to communicate with the terminal device according to the uplink transmission resource for sending the eighth message.

In yet another implementation manner, the transceiver unit 31 is configured to receive a ninth message sent by a terminal device according to a dedicated random access channel resource associated with the beam group, and the ninth message is used to initiate random access; The transceiver unit 32 is configured to send a first message to the terminal device through each beam included in the beam group, each tenth message is used to respond to the ninth message, and each ninth The message includes the same uplink transmission resource; and the transceiver unit 31 is also used to receive an eleventh message sent by the terminal device on the uplink transmission resource. The eleventh message is used to indicate the completion of the handover. The eleventh message includes the identifier of the first beam, and the first beam is a beam belonging to the beam group that satisfies the beam measurement condition.

More detailed descriptions of the above transceiver unit 31 and processing unit 32 can be directly obtained by directly referring to the relevant description of the candidate target network device in the method embodiments shown in FIGS.

An embodiment of the present application further provides a communication device, which is used to execute the above communication method. Some or all of the above communication methods may be implemented by hardware or software.

Optionally, the communication device may be a chip or an integrated circuit during specific implementation.

Optionally, when part or all of the communication method in the above embodiment is implemented by software, the communication device includes: a memory for storing a program; a processor for executing the program stored in the memory, when the program is executed, Therefore, the communication device can respectively implement the communication methods provided by the terminal device, the source network device, and the candidate target network device in the embodiments shown in FIG. 2 to FIG. 3.

Optionally, the above memory may be a physically independent unit, or may be integrated with the processor. The memory can also be used to store data.

Optionally, when part or all of the communication method in the above embodiment is implemented by software, the communication device may also include only the processor. The memory for storing the program is located outside the communication device, and the processor is connected to the memory through a circuit / wire to read and execute the program stored in the memory.

The processor may be a central processing unit (CPU), a network processor (NP), or a combination of CPU and NP.

The processor may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The PLD may be a complex programmable logic device (complex programmable logic device (CPLD), a field programmable logic gate array (field-programmable gate array, FPGA), a general array logic (generic array logic, GAL), or any combination thereof.

The memory may include volatile memory (volatile memory), such as random access memory (random-access memory, RAM); the memory may also include non-volatile memory (non-volatile memory), such as flash memory (flash memory) , Hard disk drive (HDD) or solid-state drive (SSD); the memory may also include a combination of the above types of memory.

It can be understood that the units in the foregoing embodiments of the communication device may also be referred to as modules.

FIG. 8 shows a simplified structural diagram of a terminal device. It is easy to understand and convenient to illustrate. In FIG. 8, the terminal device uses a mobile phone as an example. As shown in Fig. 8, the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and input and output devices. The processor is mainly used for processing communication protocols and communication data, as well as controlling terminal devices, executing software programs, and processing software program data. The memory is mainly used to store software programs and data. The radio frequency circuit is mainly used for the conversion of the baseband signal and the radio frequency signal and the processing of the radio frequency signal. The antenna is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, and keyboards, are mainly used to receive user input data and output data to the user. It should be noted that some types of terminal devices may not have input / output devices.

When data needs to be sent, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit processes the baseband signal after radio frequency processing, and then sends the radio frequency signal to the outside in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data. For ease of explanation, only one memory and processor are shown in FIG. 8. In actual terminal equipment products, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium, storage device, or the like. The memory may be set independently of the processor, or may be integrated with the processor, which is not limited in the embodiments of the present application.

In the embodiments of the present application, an antenna and a radio frequency circuit with a transceiver function can be regarded as a receiving unit and a sending unit of a terminal device (also collectively referred to as a transceiver unit), and a processor with a processing function as a processing unit of the terminal device . As shown in FIG. 8, the terminal device includes a transceiver unit 41 and a processing unit 42. The transceiver unit 41 may also be referred to as a receiver / transmitter (transmitter), a receiver / transmitter, a receiver / transmitter circuit, or the like. The processing unit 42 may also be referred to as a processor, processing board, processing module, processing device, or the like. The transceiver unit 41 is used to implement the function of the transceiver unit 11 in the embodiment shown in FIG. 5, and the processing unit 42 is used to implement the function of the processing unit 12 in the embodiment shown in FIG. 5.

For example, in one embodiment, the transceiver unit 41 is used to perform the functions of the terminal devices in steps S103 and S105 in the embodiment shown in FIG. 2; and the processing unit 42 is used to perform step S104 in the embodiment shown in FIG. .

For another example, in another embodiment, the transceiver unit 41 is used to perform the functions of the terminal devices in steps S205 and S207 in the embodiment shown in FIG. 3; and the processing unit 42 is used to perform the Step S206.

FIG. 9 shows a simplified schematic diagram of a network device. The network equipment includes a radio frequency signal transceiving and converting part and a part 52, and the radio frequency signal transceiving and converting part includes a transceiving unit 51 part. The RF signal transceiving and conversion part is mainly used for the transmission and reception of the RF signal and the conversion of the RF signal and the baseband signal; the 52 part is mainly used for baseband processing and controlling the network equipment. The transceiver unit 51 may also be referred to as a receiver / transmitter (transmitter), a receiver / transmitter, a receiver / transmitter circuit, or the like. Part 52 is usually the control center of the network device, and can be generally referred to as a processing unit, which is used to control the source network device to perform the steps performed by the source network device or the candidate target network device in FIGS. For details, please refer to the description of the relevant part above. The transceiver unit 51 can be used to implement the functions of the sending unit 21 and the receiving unit 22 in the embodiment shown in FIG. 6. The transceiver unit 51 can also be used to implement the functions of the receiving unit 31 and the sending unit 32 in the embodiment shown in FIG. 7, and the 52 part can also be used to implement the functions of the processing unit 33 in the embodiment shown in FIG.

Part 52 may include one or more single boards, and each single board may include one or more processors and one or more memories. The processors are used to read and execute programs in the memory to implement baseband processing functions and network devices. control. If there are multiple boards, each board can be interconnected to increase processing power. As an optional embodiment, multiple boards may share one or more processors, or multiple boards may share one or more memories, or multiple boards may share one or more processes at the same time. Device.

For example, in one embodiment, the transceiver unit 51 is used to perform the function of the source network device in steps S101 to S103 in the embodiment shown in FIG. 2.

For another example, in another embodiment, the transceiver unit 51 is used to perform the function of the source network device in steps S203 to S205 in the embodiment shown in FIG. 3.

In yet another embodiment, the transceiver unit 51 is used to perform the function of the candidate target network device in steps S101 and S102 in the embodiment shown in FIG. 2.

As another example, in another embodiment, the transceiver unit 51 is used to perform the function of the candidate target network device in steps S203 and S204 in the embodiment shown in FIG. 3; and the part 52 is used to perform the embodiment shown in FIG.的步骤 201 和 S202。 Steps 201 and S202.

Embodiments of the present application also provide a computer-readable storage medium, where the computer-readable storage medium stores a computer program or instruction, and when the computer program or instruction is executed, the method described in the above aspects is implemented.

Embodiments of the present application also provide a computer program product containing instructions, which when executed on a computer, causes the computer to execute the methods described in the above aspects.

An embodiment of the present application further provides a communication system, including the above-mentioned communication device.

Those skilled in the art can clearly understand that for the convenience and conciseness of the description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the division of the unit is only a logical function division, and there may be other divisions in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored, or not carried out. The displayed or discussed mutual coupling, direct coupling, or communication connection may be indirect coupling or communication connection through some interfaces, devices, or units, and may be in electrical, mechanical, or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transferred from a website, computer, server or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) to another A website site, computer, server or data center for transmission. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device that includes one or more available medium integrated servers, data centers, and the like. The available media may be read-only memory (ROM), or random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as, Digital versatile disc (DVD), or semiconductor media, such as solid state disk (SSD), etc.

Claims

A communication method, characterized in that it includes:

Receiving a second message from the source network device, where the second message includes: trigger switching conditions and indication information of random access channel resources;

Determine the random access channel resource that initiates random access according to the trigger switching condition and the indication information of the random access channel resource;

Initiate random access to the target network device according to the determined random access channel resource.
The method according to claim 1, wherein the indication information of the random access channel resource is used to indicate one or more of the following information: a dedicated random access channel resource is reserved; a dedicated random access is not reserved Incoming channel resources but reserved public random access channel resources; dedicated random access channel resources are not reserved and common random access channel resources are not reserved.
The method according to claim 2, wherein the second message further includes a beam signal threshold; the determining of the initiation of random access according to the trigger switching condition and the indication information of the random access channel resource Random access channel resources, including:

In a cell that satisfies the triggering switching condition, a random access channel resource associated with a beam that reserves dedicated random access channel resources and meets beam measurement conditions is determined as the random access channel resource that initiates random access;

Wherein, when the signal quality of the beam is greater than or equal to the beam signal threshold, the beam is a beam that satisfies the beam measurement condition.
The method according to claim 3, wherein the determining the random access channel resource that initiates random access according to the trigger switching condition and the indication information of the random access channel resource includes:

If no dedicated random access channel resource is reserved in the cell that satisfies the triggering switching condition and meets the beam measurement condition, it is determined that there is a beam that reserves the common random access channel resource and satisfies the beam measurement condition, Determining the common random access channel resource as the random access channel resource that initiates random access.
The method according to any one of claims 1 to 4, wherein the second message further includes an identifier of one or more candidate target cells, and an identifier of one or more beams under each candidate target cell, The second message further includes dedicated random access channel resource information, the dedicated random access channel resource includes a preamble index and a first time-frequency resource; and / or the second message further includes a common random access channel resource Information, the common random access channel resource includes a second time-frequency resource.
The method according to any one of claims 2 to 5, wherein the dedicated random access channel resource is a dedicated random access channel resource associated with the beam group;

The initiating random access to the target network device according to the determined random access channel resource includes:

Sending a third message to the target network device according to the dedicated random access channel resource associated with the beam group, where the third message is used to initiate random access, and the third message includes the identifier of the first beam, the The first beam is a beam in the beam group that satisfies the beam measurement condition;

Receiving a fourth message from the target network device through the first beam, the fourth message is a response message of the third message, and the fourth message includes uplink transmission resource information;

Use the uplink transmission resource to send a fifth message to the target network device, where the fifth message is used to indicate the completion of the handover.
A communication method, characterized in that it includes:

Sending a first message to the candidate target network device, where the first message includes reservation indication information of random access channel resources;

Receiving indication information for triggering switching conditions and random access channel resources from the candidate target network device, where the indication information of the random access channel resources is used to indicate the reservation result of the random access channel resources;

Sending a second message to the terminal device, where the second message includes the trigger switching condition and the indication information of the random access channel resource.
The method according to claim 7, wherein the first message is of a granularity of a network device, and the first message further includes an identifier of a candidate target cell and an identifier of a beam belonging to the candidate target cell;

The reservation indication information includes information indicating whether to reserve dedicated random access channel resources;

The reservation indication information is of network device granularity, cell granularity or beam granularity.
The method according to claim 7, wherein the first message is of a cell granularity, and the first message further includes an identifier of a candidate target cell and an identifier of a beam belonging to the candidate target cell;

The reservation indication information includes information indicating whether to reserve dedicated random access channel resources;

The reservation indication information is of cell granularity or beam granularity.
The method according to claim 7, wherein the reservation indication information includes a signal quality threshold of a cell and / or a signal quality threshold of a beam.
The method according to any one of claims 7 to 10, wherein the indication information of the random access channel resources is used to indicate one or more of the following information: dedicated random access channel resources are reserved; The dedicated random access channel resources are reserved but the common random access channel resources are reserved; the dedicated random access channel resources are not reserved and the common random access channel resources are not reserved.
A communication method, characterized in that it includes:

Receiving a first message from the source network device, where the first message includes random access channel resource reservation indication information;

Sending indication information that triggers a switching condition and a random access channel resource to the source network device, where the indication information of the random access channel resource is used to indicate a reservation result of the random access channel resource.
The method according to claim 12, wherein the first message is of a granularity of a network device, and the first message further includes an identifier of a candidate target cell and an identifier of a beam belonging to the candidate target cell;

The reservation indication information includes information indicating whether to reserve dedicated random access channel resources;

The reservation indication information is of network device granularity, cell granularity or beam granularity.
The method according to claim 12, wherein the first message is of a cell granularity, and the first message further includes an identifier of a candidate target cell and an identifier of a beam belonging to the candidate target cell;

The reservation indication information includes information indicating whether to reserve dedicated random access channel resources;

The reservation indication information is of cell granularity or beam granularity.
The method according to claim 12, wherein the reservation indication information includes a signal quality threshold of a cell and / or a signal quality threshold of a beam; the first message further includes an identifier of a candidate target cell, a corresponding The measurement result of the candidate target cell of the candidate, the identification of the beam belonging to the candidate target cell and the measurement result of the corresponding beam;

The method also includes:

The reservation indication information includes the signal quality threshold value of the cell. When the signal quality of the first candidate target cell is greater than or equal to the signal quality threshold value of the cell, the All beams of the first candidate target cell reserve dedicated random access channel resources; or,

The reservation indication information includes the signal quality threshold of the cell and the signal quality threshold of the beam, when the signal quality of the second candidate target cell is greater than or equal to the signal quality threshold of the cell, and the second candidate target When the signal quality of at least one beam of the cell is greater than or equal to the signal quality threshold of the beam, dedicated random access channel resources are reserved for the at least one beam.
The method according to any one of claims 12 to 15, wherein the indication information of the random access channel resources is used to indicate one or more of the following information: dedicated random access channel resources are reserved; The dedicated random access channel resources are not reserved but the common random access channel resources are reserved; the dedicated random access channel resources are not reserved and the common random access channel resources are not reserved.
The method according to any one of claims 12 to 16, wherein when the indication information of the random access channel resource is used to indicate that a dedicated random access channel resource is reserved, the method further includes : Sending dedicated random access channel resource information to the source network device;

When the indication information of the random access channel resource is used to indicate that the dedicated random access channel resource is not reserved but the common random access channel resource is reserved, the method further includes: sending a common to the source network device Random access channel resource information.
The method of claim 12, wherein the method further comprises:

Receiving a third message sent by the terminal device on a dedicated random access channel resource associated with the beam group, where the third message is used to initiate random access, and the third message includes the identifier of the first beam. The first beam is a beam belonging to the beam group that satisfies beam measurement conditions;

Sending a fourth message to the terminal device through the first beam, the fourth message is a response message of the third message, and the fourth message includes uplink transmission resource information;

Receiving a fifth message sent using the uplink transmission resource from the terminal device, where the fifth message is used to indicate that the handover is completed.
A communication device, characterized by being used to implement the method according to any one of claims 1-6.
A communication device, characterized by being used to implement the method according to any one of claims 7-11.
A communication device, characterized by being used to implement the method according to any one of claims 12-18.
A computer program product for implementing the method according to any one of claims 1-6 or the method according to any one of claims 7-11 or any one of 12-18 when executed on a computing device The method.
A computer-readable storage medium on which a computer program is stored, characterized in that when the program is executed by a processor, the method according to any one of claims 1-6 or any one of 7-11 is implemented The method of any one of 12-18.