Handover method and apparatus, network device, computer-readable storage medium, and computer program product

Abstract

The present disclosure relates to a handover method and apparatus, a network device, a computer-readable storage medium, and a computer program product. The method comprises: a first cell receives an L1 measurement report sent by a terminal, and calculates a first timing advance (TA) of a second cell on the basis of the L1 measurement report; the first cell sends a first command to the terminal, the first command being used for triggering the terminal to send a physical random access channel (PRACH) to the second cell, and the PRACH being used for the second cell to calculate a second TA; the first cell receives the second TA sent by the second cell, and performs handover decision on the basis of the first TA, the second TA, and the signal strength of the second cell; and the first cell sends a second command to the terminal on the basis of a handover decision result, the second command being used for triggering the terminal to send uplink data to the second cell on the basis of the second TA. In this way, cell handover accuracy is improved.

Description

A switching method and device, network equipment, computer-readable storage medium and computer program product

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202410167181.0 and application date of February 5, 2024, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present disclosure relates to the field of wireless communication technologies, and in particular to a switching method and apparatus, a network device, a computer-readable storage medium, and a computer program product. Background Art

[0004] Handover is a crucial process in wireless communication systems. To ensure the reliability and low latency of handovers, the 3rd Generation Partnership Project (3GPP) discussed various handover enhancements during the first 5G evolution standard, Release-16 (Rel-16) to Release-18 (Rel-18). These include a handover solution based on Conditional Handover (CHO) and a handover solution based on L1 / L2 Triggered Mobility (LTM), which controls the terminal to change multiple candidate cells (or cell groups) via Layer 1 (L1) or Layer 2 (L2) signaling. The LTM solution was a key solution discussed in Rel-18. When implementing LTM-based random access channel-less (RACH-less) cell handovers, handover failures due to latency issues may occur. Summary of the Invention

[0005] To solve the above technical problems, embodiments of the present disclosure provide a switching method and apparatus, a network device, a computer-readable storage medium, and a computer program product.

[0006] In a first aspect, an embodiment of the present disclosure provides a switching method, including:

[0007] The first cell receives an L1 measurement report sent by the terminal, and calculates a first timing advance (TA) of the second cell based on the L1 measurement report;

[0008] The first cell sends a first command to the terminal, where the first command is used to trigger the terminal to send a physical random access channel (PRACH) to the second cell, where the PRACH is used by the second cell to calculate a second TA;

[0009] The first cell receives the second TA sent by the second cell, and makes a handover decision based on the first TA, the second TA, and the signal strength of the second cell;

[0010] The first cell sends a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

[0011] In a second aspect, an embodiment of the present disclosure provides a switching device, including:

[0012] a receiving unit configured to receive an L1 measurement report sent by the terminal, and calculate a first TA of the second cell based on the L1 measurement report;

[0013] a sending unit configured to send a first command to the terminal, where the first command is used to trigger the terminal to send a PRACH to a second cell, where the PRACH is used by the second cell to calculate a second TA;

[0014] The receiving unit is configured to receive the second TA sent by the second cell;

[0015] a processing unit configured to make a handover decision based on the first TA, the second TA, and the signal strength of the second cell;

[0016] The sending unit is configured to send a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

[0017] In a third aspect, the network device provided by the embodiment of the present disclosure includes: a processor and a memory, the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute any one of the above-mentioned switching methods.

[0018] In a fourth aspect, an embodiment of the present disclosure provides a computer-readable storage medium for storing a computer program, wherein the computer program enables a computer to execute any one of the above-mentioned switching methods.

[0019] In a fifth aspect, the computer program product provided by the embodiments of the present disclosure includes computer program instructions, which enable a computer to execute any one of the switching methods described above.

[0020] In the technical solution of the embodiment of the present disclosure, the first TA of the second cell is calculated by receiving the L1 measurement report sent by the terminal in the first cell, and a first command is sent to the terminal to trigger the terminal to send PRACH to the second cell; the first cell receives the second TA sent by the second cell, and makes a switching decision based on the first TA, the second TA and the signal strength of the second cell, and sends a second command to the terminal based on the switching decision result to trigger the terminal to complete the switching from the first cell to the second cell; in this way, the success rate of the terminal in performing cell switching across distributed units (DU) is improved, efficient mobility management decisions are achieved, and the quality of service communications is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0022] FIG1 is a schematic diagram of a network architecture provided by an embodiment of the present disclosure;

[0023] FIG2 is a schematic diagram of a cell handover process according to an embodiment of the present disclosure;

[0024] FIG3 is a first schematic diagram of data transmission provided by an embodiment of the present disclosure;

[0025] FIG4 is a schematic flow chart of a switching method provided in an embodiment of the present disclosure;

[0026] FIG5 is a second schematic diagram of data transmission provided by an embodiment of the present disclosure;

[0027] FIG6 is a third schematic diagram of a cell handover process provided by an embodiment of the present disclosure;

[0028] FIG7 is a schematic diagram of the structural composition of a switching device provided in an embodiment of the present disclosure;

[0029] FIG8 is a schematic structural diagram of a network device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] The following will describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0031] To facilitate understanding of the technical solutions of the embodiments of the present disclosure, the relevant technologies of the embodiments of the present disclosure are described below. The following relevant technologies are optional solutions that can be arbitrarily combined with the technical solutions of the embodiments of the present disclosure, and they all fall within the protection scope of the embodiments of the present disclosure.

[0032] It should be noted that the terms "system" and "network" are often used interchangeably in this article. The term "and / or" in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. It should also be understood that the "indication" mentioned in the embodiments of the present disclosure can be a direct indication, an indirect indication, or an indication of an association relationship. For example, A indicates B, which can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association relationship between A and B. It should also be understood that the "correspondence" mentioned in the embodiments of the present disclosure can mean that there is a direct or indirect correspondence relationship between the two, or it can mean that there is an association relationship between the two, or it can mean a relationship between indication and indication, configuration and configuration, etc.

[0033] Figure 1 is a schematic diagram of a network architecture of an embodiment of the present disclosure. As shown in Figure 1, in New Radio (NR), the network side introduces an architecture in which the distributed unit DU and the central unit (CU) are separated, that is, the DU-CU separation architecture. In the DU-CU separation architecture, the Service Data Adaption Protocol (SDAP) entity and the Packet Data Convergence Protocol (PDCP) entity are located in the CU, the Radio Link Control (RLC) entity, the Media Access Control (MAC) entity and the physical (PHY) entity are located in the DU, and the Radio Resource Control (RRC) layer is located in the CU. The F1 interface is used to transmit control signaling and user data between the DU and the CU. The F1 interface is divided into a control plane (F1-C) and a user plane (F1-U), where F1-C provides control functions between the DU and the CU, and F1-U provides user data transmission functions between the DU and the CU. The XN control plane interface (XN-C) and user plane function interface (XN-U) are defined between two logically connected RAN nodes. Control signaling between RAN nodes is transmitted through XN-C, and user plane data between RAN nodes is transmitted through XN-U.

[0034] To facilitate understanding of the technical solutions of the embodiments of the present disclosure, the relevant technologies of the embodiments of the present disclosure are described below. The following relevant technologies are optional solutions that can be arbitrarily combined with the technical solutions of the embodiments of the present disclosure, and they all fall within the protection scope of the embodiments of the present disclosure.

[0035] Figure 2 is a schematic diagram of a cell switching process provided by an embodiment of the present disclosure. The CU is connected to the first DU and the second DU respectively through the F1 interface. The two DUs are connected to the serving cell (first cell) and the candidate cell (second cell) respectively. The two cells belong to different DUs of different base stations and share a common CU. The low-layer user plane (RLC, MAC) in the two DUs is different while the high layer (PDCP) remains the same. When the user equipment (UE) moves from the coverage area of ​​one cell to the coverage area of ​​another cell, it is necessary to perform serving cell switching. The switching process is that the UE reports the candidate cell physical cell identifier (Physical Cell Identifier, PCI) and signal strength measurement report to the serving cell, and the serving cell decides to start the switching process to the best candidate cell, and finally the best candidate cell completes the switching process. In this scenario, the UE moves from the edge of the serving cell to another candidate cell, and the different cells in different DUs process the L1 / L2-based inter-cell beam management with mobility through the UE-side protocol stack (RLC / MAC) to align the beam between the UE and the target cell during switching. As shown in Figure 2, the specific steps for implementing L1 / L2-based inter-DU cell handover with mobility are as follows:

[0036] Step 201: The first cell obtains candidate pre-configuration information of the second cell and sends a pre-configuration message of the second cell to the terminal.

[0037] Here, the first cell is a serving cell, the second cell is a candidate cell, there may be multiple candidate cells, and the pre-configuration message of the second cell is used by the terminal to measure the signal strength of the second cell.

[0038] Step 202: The first cell receives an L1 measurement report sent by the terminal.

[0039] Here, the terminal generates an L1 measurement report for the signal strengths of the first cell and the second cell.

[0040] Step 203: The first cell sends a physical downlink control channel order (PDCCH order) to the terminal.

[0041] Here, the first cell sends a PDCCH order to the terminal, triggering the terminal to send a PRACH to the second cell.

[0042] Step 204: The terminal sends a preamble code to the second cell.

[0043] Here, the terminal sends a random access channel (RACH) preamble via the PRACH channel, and the secondary cell calculates the time advance (TA) based on the preamble. The TA is used to ensure uplink time synchronization between the terminal and the cell network. A TA command is sent to notify the terminal to send uplink signals with the appropriate time advance.

[0044] Step 205: The first cell sends the TA value of the second cell to the terminal.

[0045] Here, the multiple candidate second cells send the calculated TA values ​​to the first cell, and the first cell sends the TA values ​​of the multiple candidate second cells to the terminal.

[0046] Step 206: The first cell makes a cell handover decision.

[0047] Here, the first cell determines the cell to switch based on the TA value and signal strength of the second cell.

[0048] Step 207: The first cell sends a cell switching decision to the terminal.

[0049] Here, the terminal receives the cell switching decision sent by the first cell, and the terminal completes the switching from the first cell to the second cell.

[0050] Step 208: The terminal sends uplink (UL) data to the second cell.

[0051] The terminal completes switching from the first cell to the second cell and sends uplink data to the second cell.

[0052] In the above scheme, the process of obtaining the TA value is that the terminal needs to send a RACH Preamble to the candidate cell through the PRACH channel. The candidate cell determines the corresponding TA value by reading the information. However, PRACH has false detection and misdetection, which will lead to TA calculation errors. Figure 3 is a data transmission schematic diagram provided by an embodiment of the present disclosure. As shown in Figure 3, since there is only an XN interface between different network sides, resource application and feedback, resource authorization and TA value transmission are all implemented at the MAC layer of the DU corresponding to the candidate cell, and are transmitted to the cell CU through the F1 interface to allocate uplink resources, and scheduling authorization is performed in the source cell, and then interacted with the source cell through the XN interface. This process involves many interfaces, so there will be uncontrollable delays, which is not convenient for synchronizing the system time and frequency scheduling information between the source cell and the candidate cell. The above situations will cause the terminal device to fail to switch during the movement, ultimately affecting the user experience. Therefore, in the design of future mobile communication systems, the characteristics of uncontrollable TA values ​​and delays need to be considered when performing cell switching across DUs. To this end, the technical solution of the embodiment of the present disclosure is proposed.

[0053] To facilitate understanding of the technical solutions of the embodiments of the present disclosure, the technical solutions of the present disclosure are described in detail below through specific embodiments. The above related technologies can be combined with the technical solutions of the embodiments of the present disclosure as optional solutions, and all of them fall within the scope of protection of the embodiments of the present disclosure. The embodiments of the present disclosure include at least part of the following contents.

[0054] FIG4 is a flow chart of a switching method provided by an embodiment of the present disclosure. As shown in FIG4 , the switching method includes:

[0055] Step 401: A first cell receives an L1 measurement report sent by a terminal, and calculates a first timing advance TA of a second cell based on the L1 measurement report.

[0056] It should be noted that the first cell can be called a source cell (Source Cell, Scell) or a serving cell, and the second node can be a neighboring cell (Next Cell, Ncell) or a candidate cell. The first cell and the second cell can also have other names, such as a serving cell and a candidate cell, etc., which is not limited in this disclosure.

[0057] Here, the first cell receives an L1 measurement report sent by the terminal, and the L1 measurement report includes uplink signal strengths of the first cell and the second cell measured by the terminal.

[0058] In some implementations, the first cell calculates the first timing advance TA of the second cell based on the reference signal receiving power (RSRP) in the L1 measurement report. Specifically, the path loss PL of the first cell is Scell The RS on each resource element (RE) on the channel of the first cell Scell Power (Reference Signal Power, RS power) and the maximum downlink reference signal power RSRP of the first cell Scell Specifically, PL Scell =RS Scell Power-RSRP Scell Theoretical value of timing advance of the first cell TA L PL Scell And the frequency path loss characteristics of the first cell are obtained. Specifically, TA LScell =PL Scell / Scell ​​frequency path loss characteristics. The actual value of the timing advance of the first cell TA R That is the actual cumulative value TA of the first cell RScell Theoretical value of timing advance of the first cell TA L The actual value of the timing advance of the first cell TA R The coefficient between is the spatial characteristic factor β, that is, β = TA RScell / TA LScell The path loss PL of the second cell is Ncell The power RS ​​on each RE on the channel of the second cell Ncell and the maximum downlink reference signal power RSRP of the second cell Ncell Specifically, PL Ncell =RS Ncell Power-RSRP Ncell Theoretical value of timing advance of the second cell TA L PL Ncell The frequency path loss characteristics of the second cell are obtained. Specifically, TA LNcell =PL Ncell / Scell ​​frequency path loss characteristics. The actual value of the timing advance of the second cell TA R Can be expressed as TA RNcell , then TA RNcell =TA LNcell ×β=(PL Ncell / Scell ​​frequency point path loss characteristic) × β = (PL Ncell / Scell ​​frequency point path loss characteristics)×(TA RScell / TA LScell )=(PLNcell / Scell ​​frequency point path loss characteristics)×(TA RScell / PL Scell / Scell ​​frequency point path loss characteristics).

[0059] In some embodiments, the network node on the first cell side includes a first distribution unit DU and a first central unit CU, and the network node on the second cell side includes a second DU and a second CU; wherein, there is a first interface between the first CU and the second CU, and there is a second interface between the first DU and the second DU.

[0060] Figure 5 is a second data transmission schematic diagram provided by an embodiment of the present disclosure. As shown in Figure 5, the network node on the first cell side and the network node on the second cell side adopt a DU and CU separation architecture, the network node on the first cell side includes a first CU and a first DU, and the network node on the second cell side includes a second CU and a second DU. Between the two network nodes, there is a first interface between the first CU and the second CU, and there is a second interface between the first DU and the second DU. It should be noted that the first interface can be called an XN interface or an inter-base station (NG-RAN) interface, the second interface can be called a DN interface, and the first interface and the second interface can also have other names, which are not limited in this disclosure.

[0061] In some implementations, the first cell obtains the cell reference power configuration of the second cell through the first interface, and / or sends the cell reference power configuration of the first cell to the second cell through the first interface.

[0062] Here, there is a first interface between the first CU and the second CU. During the first interface establishment process (Xn Setup) and the configuration update process (NG-RAN node Configuration Update procedure), the first interface is used to transmit the cell reference power configuration between the first cell and the second cell, and provide the first cell with the reference power configuration of the second cell.

[0063] In some implementations, the first cell obtains scheduling configuration related parameters of the second cell through the second interface, and / or sends scheduling configuration related parameters of the first cell to the second cell through the second interface.

[0064] Here, a second interface is provided between the first DU and the second DU. The second interface is used to implement the exchange of configuration parameters between the first DU and the second DU, and to implement scheduling negotiation between the first cell and the second cell. Specifically, the second interface is used to transmit cell scheduling configuration-related parameters between the first cell and the second cell. The MAC layer scheduling-related configuration parameters exchanged between the DUs may include the uplink and downlink ratio of cell time slot information, subcarrier spacing (SCS), etc.

[0065] In some embodiments, the first cell obtains the scheduling configuration related parameters of the second cell through the second interface, and / or sends the scheduling configuration related parameters of the first cell to the second cell through the second interface, including: in the establishment process of the second interface, the first cell obtains the scheduling configuration related parameters of the second cell through the second interface, and / or sends the scheduling configuration related parameters of the first cell to the second cell through the second interface; or, in the update process of the second interface, the first cell obtains the scheduling configuration related parameters of the second cell through the second interface, and / or sends the scheduling configuration related parameters of the first cell to the second cell through the second interface.

[0066] Here, there will be two triggering opportunities and new messages during the second interface establishment process. Specifically, in the second interface establishment process, the second interface is established for the first time, triggering the second interface establishment (DN Setup), and the scheduling configuration related parameters are transmitted between the first cell and the second cell through the second interface. Alternatively, during the second interface update process, the configuration related parameters between the second interfaces change, and adding or deleting a cell triggers the second interface configuration update (DN node Configuration Update procedure), and the scheduling configuration related parameters are transmitted between the first cell and the second cell through the second interface.

[0067] From the above, it can be seen that a switching method provided by an embodiment of the present disclosure sets a first interface and a second interface between a first cell and a second cell, the first interface is used to transmit the cell reference power configuration and RRC reconfiguration, and the second interface is used for cell MAC layer interaction. In this way, compared with the link process that the signaling interaction needs to go through in the prior art, that is, first passing through the F1 interface of the candidate cell, then passing through the XN interface between the candidate cell and the serving cell, and finally transmitted to the DU of the serving cell through the FI interface of the serving cell, the switching method provided by the embodiment of the present disclosure reduces the message forwarding path, reduces the signaling interaction delay, and facilitates the synchronization of timing information between MACs.

[0068] In some implementations, before the first cell receives the L1 measurement report sent by the terminal, the method further includes:

[0069] The first cell obtains the radio resource control RRC reconfiguration of the second cell through the first interface; the first cell sends the RRC reconfiguration of the second cell to the terminal, and the RRC reconfiguration is used by the terminal to establish an RRC connection with the second cell.

[0070] Here, before the first cell receives the L1 measurement report sent by the terminal, it is necessary to send a radio resource control RRC reconfiguration message of the second cell to the terminal. The RRC reconfiguration of the second cell is used by the terminal to establish an RRC connection with the second cell. Specifically, the first CU of the first cell obtains the radio resource control RRC reconfiguration related information of the second cell through the first interface, and sends an RRC reconfiguration message to the terminal as an RRCReconfiguration message. The reconfiguration information includes measurement configuration information, measurement object, report configuration, and measurement identifier, among which the measurement object includes parameters such as cell frequency band, synchronization signal block (SSB), and subcarrier spacing.

[0071] Step 402: The first cell sends a first command to the terminal. The first command is used to trigger the terminal to send a physical random access channel PRACH to the second cell. The PRACH is used by the second cell to calculate a second TA.

[0072] In some embodiments, before the first cell sends the first command to the terminal, the process further includes: the first cell sending a random access (RA) resource request message to the second cell through the second interface, and receiving the RA resource request response message sent by the second cell through the second interface.

[0073] In some embodiments, the RA resource request message carries at least one of the following information: the type of RA resource request, the cell identification information of the first cell, the cell identification information of the second cell, the relevant information between cells of the second interface for scheduling timing calculation, and the minimum scheduling advance time requirement of the first cell; the scheduling advance information is used for the second cell to make uplink scheduling time domain decisions.

[0074] In some implementations, the RA resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and RA resources; the RA resources include at least one of the following information: PRACH sequence information, PRACH time domain information, and PRACH frequency domain information.

[0075] Here, before the first cell sends the first command to the terminal, the first cell establishes an RA resource application process with the second cell through the second interface. The first cell sends an RA resource application message to the second cell to indicate the type of RA resource application (periodic or non-periodic), the first cell identification information and the second cell identification information, and transmits relevant information used for scheduling timing calculation between cells through the second interface, such as the uplink and downlink ratio of cell time slot information, the system frame number (SFN), and the minimum scheduling advance time requirement of the first cell for the second cell to make uplink scheduling time domain decisions. The first cell receives the RA resource application response message sent by the second cell, and the RA resource application response message carries the first cell identification information and the second cell identification information, periodic PRACH information or non-periodic PRACH sequence information, PRACH sending time domain information, and PRACH sending frequency domain information.

[0076] From the above, it can be seen that a switching method provided by an embodiment of the present disclosure proposes non-periodic scheduling of dedicated PRACH resources during the RA resource negotiation process between the first cell and the second cell. In this way, it not only improves the delay problem of PRACH triggering, but also reduces the complexity of calculating the time-frequency position of the PRACH transmission of the second cell in the first cell.

[0077] In some embodiments, after the first cell completes the RA resource application process with the second cell through the second interface, the first cell sends a first command to the terminal, the first command carries information for triggering the terminal to initiate random access to the second cell, and sends a physical random access channel PRACH to the second cell.

[0078] In some embodiments, the first command is a physical downlink control channel command PDCCH order or a first media access control element (MAC Control Element, MAC CE); the PDCCH order or the first MAC CE carries first information and second information, the first information includes at least part of the information in the RA resource application response message, and the second information is used to indicate the first TA; wherein the first information and the second information are used by the terminal to send PRACH to the second cell using RA resources based on the first TA.

[0079] In some embodiments, when the first command is a PDCCH order, the PDCCH order carries first information and second information. The first information includes at least part of the information in the above-mentioned RA resource request response message, for example, the first information includes: cell identifier or index (Cell indicator\index), frequency domain resource allocation information (Frequency Domain Resource Assignment), time domain resource allocation information (Time Domain Resource Assignment), random access preamble index (Random Access Preamble index) (the random access preamble index can be but is not limited to being represented by 6 bits), synchronization signal block index (SS / PBCH index) (the synchronization signal block index can be but is not limited to being represented by 6 bits), PRACH mask index (PRACH Mask index) (the PRACH mask index can be but is not limited to being represented by 4 bits). The second information is used to indicate the first TA, for example, the second information is a TA command (Timing Advance Command). Exemplarily, referring to the following Table 1, the PDCCH order of the periodic PRACH format has the following PDCCH format (PDDCH format):

[0080] Table 1

[0081] Exemplarily, referring to the following Table 2, the PDCCH order of the aperiodic PRACH format has the following PDCCH format (PDDCH format):

[0082] Table 2

[0083] Here, it should be emphasized that a TA field (i.e., TA command) is added to the PDCCH order command to indicate the first TA. In this way, the terminal can use the first TA to send PRACH to the second cell on the RA resources. That is, the terminal considers the influence of the first TA during the random access process.

[0084] In some embodiments, when the first command is a first MAC CE, the first MAC CE carries first information and second information. The first information includes at least part of the information in the above-mentioned RA resource request response message, for example, the first information includes: cell identifier or index (Cell indicator\index), frequency domain resource allocation information (Frequency Domain Resource Assignment), time domain resource allocation information (Time Domain Resource Assignment), random access preamble index (Random Access Preamble index), synchronization signal block index (SS / PBCH index). The second information is used to indicate the first TA, for example, the second information is a TA command (Timing Advance Command). Exemplarily, referring to Table 3 below, the MAC CE in the periodic PRACH mode has the following MAC CE format (MAC CE format):

[0085] Table 3

[0086] Exemplarily, referring to the following Table 4, the MAC CE in the aperiodic PRACH mode has the following MAC CE format:

[0087] Table 4

[0088] Here, it should be emphasized that a TA field (i.e., TA command) is added to the newly added first MAC CE command to indicate the first TA. In this way, the terminal can use the first TA to send PRACH to the second cell on the RA resources. That is to say, the terminal takes into account the influence of the first TA during the random access process.

[0089] In some embodiments, the first information and the second information are used by the terminal to utilize RA resources according to the first TA. The terminal triggers random access to the second cell and sends a PRACH to the second cell. The PRACH is used by the second cell to calculate the second TA. Specifically, the terminal generates a RACH preamble code based on the first information and the second information, and sends the PRACH to the second cell along with the RACH preamble code. The second cell receives the PRACH and calculates the second TA based on the carried RACH preamble code, and sends the second TA to the first cell via the second interface.

[0090] From the above, it can be seen that a switching method provided by an embodiment of the present disclosure adds a TA field in the first PDCCH order command or adds a TA field in the new first MAC CE command, and triggers the PRACH message through the first command. In this way, the TA impact is considered during the random access process of the terminal, thereby improving the detection performance of the PRACH.

[0091] Step 403: The first cell receives the second TA sent by the second cell, and makes a handover decision based on the first TA, the second TA, and the signal strength of the second cell.

[0092] In some implementations, the first cell receiving the second TA sent by the second cell includes: the first cell receiving the second TA sent by the second cell through a second interface.

[0093] Here, the second cell receives the PRACH sent by the terminal and calculates a second TA based on the carried RACH preamble code. The second cell sends the second TA to the first cell via the second interface. The first cell receives the second TA sent by the second cell and makes a handover decision for the target cell based on the two TA calculation results and the signal strength measurement of the second cell. Specifically, the first cell selects the target cell based on the signal strength of the second cell and the TA trend of the second cell.

[0094] In some embodiments, a switching decision is made based on the first TA, the second TA, and the signal strength of the second cell, including: if the difference between the first TA and the second TA meets the first condition and the signal strength of the second cell meets the second condition, then determining the second cell as the target cell for switching.

[0095] Here, the first cell selects the destination cell for switching based on the signal strength combined with the TA trend. The changes in the first TA and the second TA measured twice indicate the trend of the terminal moving toward the center of the destination cell. Specifically, the difference between the first TA and the second TA can be expressed as deltaTA, the first TA is expressed as TA1, and the second TA is expressed as TA2, then deltaTA=TA1-TA2; when deltaTA is greater than or equal to 0, it means that the difference between the first TA and the second TA meets the first condition, and it means that the terminal is moving toward the center of the destination cell. The larger the deltaTA value, the greater the weight of the second cell, which means that the second cell is closer to the center of the destination cell; the smaller the deltaTA value, the smaller the weight of the second cell, which means that the second cell is farther away from the center of the destination cell. When the signal strength of the second cell meets the second condition, the second cell that moves the fastest toward the center of the destination cell is determined as the destination cell for switching.

[0096] From the above, it can be seen that a switching method provided by an embodiment of the present disclosure calculates the first TA of the second cell through the first cell, receives the second TA sent by the second cell, and determines the switching of the target cell based on the difference between the first TA and the second TA and whether the signal strength of the second cell meets the conditions; in this way, the correctness of the target cell selection is increased by utilizing the terminal's movement trend, thereby improving the success rate of the switching; at the same time, the process of configuring the TA values ​​of multiple candidate cells to the terminal in advance is reduced, making the system and process more reasonable and simple.

[0097] Step 404: The first cell sends a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

[0098] Here, when the first cell determines that the second cell is the target cell for handover, it sends a second command to the terminal. The terminal determines to handover from the first cell to the second cell according to the second command and sends uplink data to the second cell.

[0099] In some embodiments, before the first cell sends the second command to the terminal based on the switching decision result, it also includes: the first cell sends an uplink resource request message to the second cell through the second interface, and receives an uplink resource request response message sent by the second cell through the second interface.

[0100] In some embodiments, the uplink resource request message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, relevant information for scheduling timing calculation between cells of the second interface, and the minimum scheduling advance time requirement of the first cell; the scheduling advance information is used by the second cell to make uplink scheduling time domain decisions.

[0101] In some implementations, the uplink resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and uplink resources.

[0102] In some implementations, the uplink resources include at least one of the following information: uplink time domain information, uplink frequency domain information, Hybrid Automatic Repeat Quest (HARQ) information, modulation and coding information, uplink power information, and redundancy version information.

[0103] Here, before the first cell sends the second command to the terminal based on the handover decision result, the first cell establishes an uplink resource application process with the second cell through the second interface. The first cell sends an uplink resource application message, the first cell identification information and the second cell identification information to the second cell, and transmits relevant information used for scheduling timing calculation between cells through the second interface, such as the cell time slot uplink and downlink ratio information, the system frame number SFN, and the minimum scheduling advance time requirement of the first cell for the second cell to make an uplink scheduling time domain decision. The first cell receives the uplink resource application response message sent by the second cell, the uplink resource application response message carries the first cell identification information and the second cell identification information, and periodically sends uplink time domain information, frequency domain information, HARQ information, modulation and coding scheme (MCS), resource indication value (RIV) information, redundant version information, etc.

[0104] In some implementations, the first cell transmits relevant information of the uplink resource application process in a bit stream in the form of a protocol data unit (PDU) in the form of an L2 MAC CE via the second interface.

[0105] In some embodiments, after the first cell completes the UL resource application process with the second cell through the second interface, the first cell sends a second command to the terminal based on the switching decision result, and the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

[0106] In some embodiments, the second command is a second MAC CE or downlink control information (DCI), the second MAC CE or DCI carries third information and fourth information, the third information includes at least part of the information in the uplink resource request response message, and the fourth information is used to indicate the second TA; wherein the third information and the fourth information are used by the terminal to send uplink data to the second cell using uplink resources based on the second TA.

[0107] In some embodiments, when the second command is a second MAC CE, the second MAC CE carries third information and fourth information. The third information includes at least part of the information in the above-mentioned uplink resource request response message, for example, the third information includes: cell identifier or index (Cell indicator\index), frequency domain resource allocation information (Frequency Domain Resource assignment), time domain resource allocation information (Time Domain Resource Assignment), coding and modulation scheme (Modulation And Coding Scheme), redundancy version information (Redundancy Version), hybrid automatic repeat request process number (HARQ Process Number), uplink power control TPC parameter (TPC Command For Scheduled PUSCH) indicating the physical uplink shared channel (Physical Uplink Shared Channel, PUSCH), and beam alignment information. The fourth information is used to indicate the second TA, for example, the fourth information is a TA command (Timing Advance Command). Exemplarily, referring to the following Table 5, the second MAC CE has the following MAC CE format (MAC CE format):

[0108] Table 5

[0109] Here, it should be emphasized that a TA field (i.e., TA command) is added to the newly added second MAC CE command to indicate the second TA. In this way, the terminal can use the second TA to transmit data directly on the second cell, that is, the terminal takes into account the influence of the second TA during uplink data transmission.

[0110] In some embodiments, when the second command is DCI, the DCI carries third information and fourth information. The third information includes at least part of the information in the above-mentioned uplink resource request response message, for example, the third information includes: cell identification or cell index (Cell indicator\index), frequency domain resource allocation information (Frequency Domain Resource Assignment), time domain resource allocation information (Time Domain Resource Assignment), coding modulation scheme (Modulation And Coding Scheme), redundancy version information (Redundancy Version), hybrid automatic repeat request process number (HARQ Process Number), uplink power control TPC parameter (TPC Command For Scheduled PUSCH) indicating the physical uplink shared channel (Physical Uplink Shared Channel, PUSCH), and beam alignment information. The fourth information is used to indicate the second TA, for example, the fourth information is a TA command (Timing Advance Command). Exemplarily, with reference to the following Table 6, the DCI has the following PDDCH format (PDDCH format):

[0111] Table 6

[0112] Here, it should be emphasized that a TA field (i.e., TA command) is added to the DCI command to indicate the second TA. In this way, the terminal can use the second TA to transmit data directly on the second cell. In other words, the terminal takes into account the influence of the second TA when transmitting data to the second cell.

[0113] From the above, it can be seen that a switching method provided by an embodiment of the present disclosure, on the one hand, by defining a new second MAC CE or a new DCI command, enables the second cell to receive uplink data at a RACH-FREE scheduling time-frequency position, and supports triggering the terminal to directly transmit data on the second cell; on the other hand, by adding a TA field in the second command, the terminal takes the TA impact into consideration during the random access process.

[0114] In some embodiments, the third information and the fourth information are used by the terminal to utilize UL resources according to the second TA, and the terminal triggers the transmission of uplink data to the second cell. Specifically, after receiving the second command from the first cell, the terminal determines to switch from the first cell to the second cell, and sends uplink data to the second cell according to the second TA, thereby completing the handover between the terminal and the destination cell.

[0115] From the above, it can be seen that the embodiment of the present disclosure proposes a switching method, in which the first TA of the second cell is calculated by receiving the L1 measurement report sent by the terminal in the first cell, and a first command is sent to the terminal to trigger the terminal to send PRACH to the second cell; the first cell receives the second TA sent by the second cell, and makes a switching decision based on the first TA, the second TA and the signal strength of the second cell, and sends a second command to the terminal based on the switching decision result to trigger the terminal to complete the switching from the first cell to the second cell; in this way, the success rate of the terminal in performing cell switching across DUs is improved, efficient mobility management decisions are achieved, and the quality of service communications is guaranteed.

[0116] Example 1

[0117] FIG6 is a third schematic diagram of a cell handover process provided by an embodiment of the present disclosure. As shown in FIG6 , the specific handover steps for a terminal to switch from a first cell to a second cell are as follows:

[0118] Step 601: A first cell sends first cell and second cell pre-configuration information to a terminal, including L1 measurement information configuration.

[0119] Here, the first cell obtains pre-configuration information of the second cell through the first interface, where the pre-configuration information includes RRC reconfiguration, cell reference power configuration, and the like.

[0120] Step 602: After receiving the pre-configuration information sent by the first cell, the terminal sends an L1 measurement report to the first cell.

[0121] Here, the L1 measurement report includes uplink signal strengths of the first cell and the second cell measured by the terminal. The first cell calculates a first timing advance TA of the second cell according to the reference signal received power in the L1 measurement report.

[0122] Step 603: The first cell sends a random access RA resource request message to the second cell through the second interface, and receives an RA resource request response message sent by the second cell through the second interface.

[0123] Here, the RA resource request message carries at least one of the following information: the type of RA resource request, the cell identification information of the first cell, the cell identification information of the second cell, the relevant information used for scheduling timing calculation between cells of the second interface, and the minimum scheduling advance time requirement of the first cell; the scheduling advance information is used for the second cell to make uplink scheduling time domain decisions.

[0124] Here, the RA resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and RA resources; RA resources include at least one of the following information: PRACH sequence information, PRACH time domain information, and PRACH frequency domain information.

[0125] Step 604: The first cell sends a first command to the terminal, where the first command carries the first information and the second information.

[0126] Here, the first command is a PDCCH order or a first MAC CE; the PDCCH order or the first MAC CE carries first information and second information, the first information includes at least part of the information in the RA resource request response message, and the second information is used to indicate the first TA.

[0127] Step 605: The terminal sends a PRACH carrying a preamble code to the second cell using RA resources based on the first TA, and the second cell calculates a second TA according to the preamble code.

[0128] Step 606: The second cell sends a second TA to the first cell.

[0129] Step 607: The first cell receives the second TA sent by the second cell, and makes a handover decision based on the first TA, the second TA, and the signal strength of the second cell.

[0130] Here, if the difference between the first TA and the second TA meets the first condition and the signal strength of the second cell meets the second condition, the second cell is determined to be the destination cell for switching. Specifically, the difference between the first TA and the second TA can be expressed as deltaTA, the first TA is expressed as TA1, and the second TA is expressed as TA2, then deltaTA=TA1-TA2; when deltaTA is greater than or equal to 0, it means that the difference between the first TA and the second TA meets the first condition, and this indicates that the terminal is moving toward the center of the destination cell. When the deltaTA value is larger, the weight of the second cell is larger, indicating that the second cell is closer to the center of the destination cell; the smaller the deltaTA value is, the smaller the weight of the second cell is, indicating that the second cell is farther away from the center of the destination cell. When the signal strength of the second cell meets the second condition, the second cell that moves the fastest toward the center of the destination cell is determined to be the destination cell selected for switching.

[0131] Step 608: The first cell sends an uplink resource request message to the second cell through the second interface, and receives an uplink resource request response message sent by the second cell through the second interface.

[0132] Here, the uplink resource request message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, relevant information used for scheduling timing calculation between cells of the second interface, and scheduling advance information; the scheduling advance information is used by the second cell to make uplink scheduling time domain decisions.

[0133] The uplink resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and uplink resources.

[0134] The uplink resources include at least one of the following information: uplink time domain information, uplink frequency domain information, HARQ information, modulation and coding information, uplink power information, and redundant version information.

[0135] Step 609: The first cell sends a second command to the terminal based on the handover decision result, where the second command carries the third information and the fourth information.

[0136] Here, the second command is a second MAC CE or DCI, the second MAC CE or DCI carries third information and fourth information, the third information includes at least part of the information in the uplink resource request response message, and the fourth information is used to indicate the second TA.

[0137] Step 610: The terminal completes switching from the first cell to the second cell according to the second command, and sends uplink data to the second cell.

[0138] FIG7 is a schematic diagram of the structure of a switching device provided by an embodiment of the present disclosure, which is applied to a first cell. As shown in FIG7 , the switching device 700 includes:

[0139] The receiving unit 701 is configured to receive an L1 measurement report sent by a terminal, and calculate a first TA of a second cell based on the L1 measurement report.

[0140] The sending unit 702 is configured to send a first command to the terminal, where the first command is used to trigger the terminal to send a PRACH to the second cell, where the PRACH is used by the second cell to calculate a second TA.

[0141] The receiving unit 701 is configured to receive a second TA sent by a second cell.

[0142] The processing unit 703 is configured to make a handover decision based on the first TA, the second TA and the signal strength of the second cell.

[0143] The sending unit 702 is configured to send a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

[0144] In some embodiments, the network node on the first cell side includes a first distribution unit DU and a first central unit CU, and the network node on the second cell side includes a second DU and a second CU; wherein, there is a first interface between the first CU and the second CU, and there is a second interface between the first DU and the second DU.

[0145] In some implementations, the receiving unit 701 is configured to obtain the cell reference power configuration of the second cell through the first interface.

[0146] In some implementations, the sending unit 702 is configured to send the cell reference power configuration of the first cell to the second cell via the first interface.

[0147] In some implementations, the receiving unit 701 is configured to obtain scheduling configuration related parameters of the second cell through the second interface.

[0148] In some implementations, the sending unit 702 is configured to send scheduling configuration related parameters of the first cell to the second cell via the second interface.

[0149] In some embodiments, in the establishment process of the second interface, the receiving unit 701 is configured to obtain the scheduling configuration related parameters of the second cell through the second interface, and / or the sending unit 702 is configured to send the scheduling configuration related parameters of the first cell to the second cell through the second interface; or, in the update process of the second interface, the receiving unit 701 is configured to obtain the scheduling configuration related parameters of the second cell through the second interface, and / or the sending unit 702 is configured to send the scheduling configuration related parameters of the first cell to the second cell through the second interface.

[0150] In some embodiments, before the receiving unit 701 receives the L1 measurement report sent by the terminal, it is configured to obtain the radio resource control RRC reconfiguration of the second cell through the first interface; the sending unit 702 is configured to send the RRC reconfiguration of the second cell to the terminal, and the RRC reconfiguration is used by the terminal to establish an RRC connection with the second cell.

[0151] In some embodiments, before sending the first command to the terminal, the sending unit 702 is configured to send a random access RA resource request message to the second cell through the second interface, and the receiving unit 701 is configured to receive the RA resource request response message sent by the second cell through the second interface.

[0152] In some embodiments, the RA resource request message carries at least one of the following information: the type of RA resource request, the cell identification information of the first cell, the cell identification information of the second cell, the relevant information between cells of the second interface for scheduling timing calculation, and the minimum scheduling advance time requirement of the first cell; the scheduling advance information is used for the second cell to make uplink scheduling time domain decisions.

[0153] In some embodiments, the RA resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and RA resources; the RA resources include at least one of the following information: PRACH sequence information, PRACH time domain information, PRACH frequency domain information, and PRACH SCS.

[0154] In some embodiments, the first command is a PDCCH order or a first MAC CE; the PDCCH order or the first MAC CE carries first information and second information, the first information includes at least part of the information in the RA resource application response message, and the second information is used to indicate the first TA; wherein the first information and the second information are used by the terminal to send PRACH to the second cell based on the first TA using RA resources.

[0155] In some implementations, the receiving unit 701 is configured to receive a second TA sent by a second cell through a second interface.

[0156] In some implementations, the processing unit 703 is configured to determine that the second cell is the target cell for handover if the difference between the first TA and the second TA meets a first condition and the signal strength of the second cell meets a second condition.

[0157] In some embodiments, before sending the second command to the terminal based on the switching decision result, the sending unit 702 is configured to send an uplink resource request message to the second cell through the second interface, and the receiving unit 701 is configured to receive an uplink resource request response message sent by the second cell through the second interface.

[0158] In some embodiments, the uplink resource request message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, relevant information for scheduling timing calculation between cells of the second interface, and the minimum scheduling advance time requirement of the first cell; the scheduling advance information is used by the second cell to make uplink scheduling time domain decisions.

[0159] In some implementations, the uplink resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and uplink resources.

[0160] In some implementations, the uplink resources include at least one of the following information: uplink time domain information, uplink frequency domain information, HARQ information, modulation and coding information, uplink power information, and redundant version information.

[0161] In some embodiments, the second command is a second MAC CE or DCI, the second MAC CE or DCI carries third information and fourth information, the third information includes at least part of the information in the uplink resource request response message, and the fourth information is used to indicate the second TA; wherein the third information and the fourth information are used by the terminal to send uplink data to the second cell using uplink resources based on the second TA.

[0162] Those skilled in the art will appreciate that the functions of each unit in the switching device shown in FIG7 can be understood with reference to the relevant description of the aforementioned method. The functions of each unit in the switching device shown in FIG7 can be implemented by a program running on a processor or by a specific logic circuit.

[0163] Figure 8 is a schematic structural diagram of a network device 800 provided in an embodiment of the present disclosure. The network device 800 shown in Figure 8 includes a processor 810, which can call and run a computer program from a memory to implement the method in the embodiment of the present disclosure.

[0164] Optionally, as shown in Figure 8, the network device 800 may further include a memory 820. The processor 810 may call and execute a computer program from the memory 820 to implement the method in the embodiment of the present disclosure.

[0165] The memory 820 may be a separate device independent of the processor 810 , or may be integrated into the processor 810 .

[0166] Optionally, as shown in FIG8 , the network device 800 may further include a transceiver 830 , and the processor 810 may control the transceiver 830 to communicate with other devices, specifically, to send information or data to other devices, or to receive information or data sent by other devices.

[0167] The transceiver 830 may include a transmitter and a receiver. The transceiver 830 may further include an antenna, and the number of antennas may be one or more.

[0168] Optionally, the network device 800 may specifically be the network device of an embodiment of the present disclosure, and the network device 800 may implement the corresponding processes implemented by the network device in each method of the embodiment of the present disclosure. For the sake of brevity, they will not be repeated here.

[0169] It should be understood that the processor of the embodiments of the present disclosure may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above-mentioned method embodiment can be completed by hardware integrated logic circuits in the processor or by software instructions. The above-mentioned processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present disclosure can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of the present disclosure can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above-mentioned method.

[0170] It is understood that the memory in the embodiments of the present disclosure may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0171] It should be understood that the above-mentioned memories are exemplary but not restrictive. For example, the memories in the embodiments of the present disclosure may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM RAM (DR RAM), etc. In other words, the memories in the embodiments of the present disclosure are intended to include, but are not limited to, these and any other suitable types of memories.

[0172] The embodiment of the present disclosure also provides a computer-readable storage medium for storing a computer program.

[0173] Optionally, the computer-readable storage medium can be applied to the network node (such as an intelligent repeater) in the embodiments of the present disclosure, and the computer program enables the computer to execute the corresponding processes implemented by the network node (such as an intelligent repeater) in the various methods of the embodiments of the present disclosure. For the sake of brevity, they will not be repeated here.

[0174] Optionally, the computer-readable storage medium can be applied to the base station in the embodiments of the present disclosure, and the computer program enables the computer to execute the corresponding processes implemented by the base station in the various methods of the embodiments of the present disclosure. For the sake of brevity, they are not repeated here.

[0175] An embodiment of the present disclosure also provides a computer program product, including computer program instructions.

[0176] Optionally, the computer program product can be applied to the network node (such as an intelligent repeater) in the embodiments of the present disclosure, and the computer program instructions enable the computer to execute the corresponding processes implemented by the network node (such as an intelligent repeater) in the various methods of the embodiments of the present disclosure. For the sake of brevity, they will not be repeated here.

[0177] Optionally, the computer program product can be applied to the base station in the embodiments of the present disclosure, and the computer program instructions enable the computer to execute the corresponding processes implemented by the base station in the various methods of the embodiments of the present disclosure. For the sake of brevity, they are not repeated here.

[0178] The embodiments of the present disclosure also provide a computer program.

[0179] Optionally, the computer program can be applied to the network nodes (such as smart repeaters) in the embodiments of the present disclosure. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the network nodes (such as smart repeaters) in the various methods of the embodiments of the present disclosure. For the sake of brevity, they will not be repeated here.

[0180] Optionally, the computer program can be applied to the base station in the embodiments of the present disclosure. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the base station in the various methods of the embodiments of the present disclosure. For the sake of brevity, they are not repeated here.

[0181] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0182] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0183] In the several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0184] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0185] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0186] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0187] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A handover method, comprising: The first cell receives an L1 measurement report sent by the terminal, and calculates a first timing advance TA of the second cell based on the L1 measurement report; The first cell sends a first command to the terminal, where the first command is used to trigger the terminal to send a physical random access channel (PRACH) to the second cell, where the PRACH is used by the second cell to calculate a second TA; The first cell receives the second TA sent by the second cell, and makes a handover decision based on the first TA, the second TA, and the signal strength of the second cell; The first cell sends a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

2. The method according to claim 1, wherein The network node on the first cell side includes a first distribution unit DU and a first central unit CU, and the network node on the second cell side includes a second DU and a second CU; wherein, there is a first interface between the first CU and the second CU, and there is a second interface between the first DU and the second DU.

3. The method according to claim 2, wherein: The method further comprises: The first cell obtains the cell reference power configuration of the second cell through the first interface, and / or sends the cell reference power configuration of the first cell to the second cell through the first interface.

4. The method according to claim 2, wherein: The method further comprises: The first cell obtains scheduling configuration related parameters of the second cell through the second interface, and / or sends scheduling configuration related parameters of the first cell to the second cell through the second interface.

5. The method according to claim 4, wherein The first cell acquiring, through the second interface, scheduling configuration related parameters of the second cell, and / or sending, through the second interface, scheduling configuration related parameters of the first cell to the second cell, includes: In the process of establishing the second interface, the first cell obtains scheduling configuration related parameters of the second cell through the second interface, and / or sends scheduling configuration related parameters of the first cell to the second cell through the second interface; or, In the update process of the second interface, the first cell obtains the scheduling configuration related parameters of the second cell through the second interface, and / or sends the scheduling configuration related parameters of the first cell to the second cell through the second interface.

6. The method according to claim 2, wherein: Before the first cell receives the L1 measurement report sent by the terminal, the method further includes: The first cell obtains, through the first interface, a radio resource control (RRC) reconfiguration of the second cell; The first cell sends the RRC reconfiguration of the second cell to the terminal, where the RRC reconfiguration is used by the terminal to establish an RRC connection with the second cell.

7. The method according to claim 2, wherein: Before the first cell sends the first command to the terminal, the method further includes: The first cell sends a random access RA resource request message to the second cell through the second interface, and receives an RA resource request response message sent by the second cell through the second interface; The RA resource request message carries at least one of the following information: type of RA resource request, cell identification information of the first cell, cell identification information of the second cell, related information for scheduling timing calculation between cells of the second interface, and minimum scheduling advance time requirement of the first cell; the scheduling advance information is used by the second cell to make uplink scheduling time domain decisions; The RA resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and RA resources; the RA resources include at least one of the following information: PRACH sequence information, PRACH time domain information, PRACH frequency domain information, and PRACH SCS information.

8. The method according to claim 7, wherein: The first command is a physical downlink control channel command PDCCH order or a first media access control element MAC CE; the PDCCH order or the first MAC CE carries first information and second information, the first information includes at least part of the information in the RA resource application response message, and the second information is used to indicate the first TA; wherein the first information and the second information are used by the terminal to send a PRACH to the second cell using the RA resources based on the first TA.

9. The method according to claim 2, wherein: The first cell receiving the second TA sent by the second cell includes: The first cell receives the second TA sent by the second cell through the second interface.

10. The method according to claim 1, wherein The performing handover decision based on the first TA, the second TA, and the signal strength of the second cell includes: If the difference between the first TA and the second TA meets a first condition and the signal strength of the second cell meets a second condition, the second cell is determined to be the target cell for handover.

11. The method according to claim 2, wherein: Before the first cell sends the second command to the terminal based on the handover decision result, the method further includes: The first cell sends an uplink resource request message to the second cell through the second interface, and receives an uplink resource request response message sent by the second cell through the second interface; The uplink resource request message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, related information for scheduling timing calculation between cells of the second interface, and a minimum scheduling advance time requirement of the first cell; the scheduling advance information is used by the second cell to make an uplink scheduling time domain decision; The uplink resource request response message carries at least one of the following information: cell identification information of the first cell, cell identification information of the second cell, and uplink resources; the uplink resources include at least one of the following information: uplink time domain information, uplink frequency domain information, hybrid automatic repeat request HARQ information, modulation and coding information, uplink power information, redundant version information, and beam alignment information.

12. The method according to claim 11, wherein The second command is a second MAC CE or downlink control information DCI, the second MAC CE or the DCI carries third information and fourth information, the third information includes at least part of the information in the uplink resource application response message, and the fourth information is used to indicate the second TA; wherein, the third information and the fourth information are used by the terminal to send uplink data to the second cell using the uplink resources based on the second TA.

13. A switching device, comprising: a receiving unit configured to receive an L1 measurement report sent by the terminal, and calculate a first TA of the second cell based on the L1 measurement report; a sending unit configured to send a first command to the terminal, where the first command is used to trigger the terminal to send a PRACH to a second cell, where the PRACH is used by the second cell to calculate a second TA; The receiving unit is configured to receive the second TA sent by the second cell; a processing unit configured to make a handover decision based on the first TA, the second TA, and the signal strength of the second cell; The sending unit is configured to send a second command to the terminal based on the handover decision result, where the second command is used to trigger the terminal to send uplink data to the second cell based on the second TA.

14. A network device comprising: A processor and a memory, the memory being used to store a computer program, the processor being used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 12.

15. A computer-readable storage medium for storing a computer program, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 12.

16. A computer program product comprising computer program instructions, the computer program instructions causing a computer to execute the method according to any one of claims 1 to 12.

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