Method and device for controlling SR sending in LTM switching

Abstract

Disclosed are a method and device for controlling SR transmission in LTM cell handover, the method comprising: receiving an RRC signaling sent by a source cell, the RRC signaling comprising configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell comprises a first execution condition; performing LTM cell handover in response to the first execution condition being satisfied; initiating a process of sending the SR to the target cell, wherein the process of sending the SR to the target cell depends on whether the executed LTM cell switching is the LTM cell switching based on the RACH or the LTM cell switching without the RACH; according to the method and the device, the condition-based RACH-free LTM cell switching can be better supported, the resource waste is avoided, and the time delay of the LTM cell switching is reduced.

Description

Technical Field

[0001] The present invention relates to a transmission method and device in a wireless communication system, and in particular to a method and device in LTM cell switching. Background Art

[0002] With the continuous development of wireless communications, the requirements for mobility are becoming higher and higher, for example, shorter interruption delay. The 3rd Generation Partner Project (3GPP) RAN (Radio Access Network) #94e meeting decided to study Layer 1 (L1) / L2 (Layer 2) triggered mobility (L1 / L2 Triggered Mobility, LTM) in the "New Radio (NR) Mobility Further Enhancements (Further NRmobility enhancements)" research project (Work Item, WI).

[0003] Layer 3 (L3) mobility has evolved over several releases. The evolution of conditional handover (conditionalCHO) and other conditional migration procedures (CPAC, SCPAC) can also be performed without prior signaling interaction with the source cell, thereby achieving high robustness. LTM introduced in Rel-18 provides a shorter interruption time, but its robustness is not as good as the conditional L3 migration procedure. In Rel-19, enhancements should be specified so that the system can benefit from high robustness and short interruptions. Summary of the invention

[0004] When the UE performs the existing L3 handover, the random access process is triggered, which is not conducive to the UE service continuity. However, when LTM handover is adopted, although the interruption time can be shortened, the robustness may be affected. Therefore, it is necessary to enhance the robustness of LTM cell handover, especially to enhance the robustness of LTM cell handover without RACH.

[0005] In view of the above problems, the present invention provides a mobility solution. In view of the above problem description, the NR system is used as an example. The present invention is also applicable to scenarios such as the LTE (Long-Term Evolution) system, and obtains technical effects similar to those of the NR system; further, although the present invention provides a specific implementation method for LTM, the present invention can also be used in scenarios such as PSCell changes, and obtain technical effects similar to those of LTM. Further, although the original intention of the present invention is for the Uu air interface, the present invention can also be used for the PC5 port, and obtain technical effects similar to those of the Uu air interface. Further, although the original intention of the present invention is for the terminal and base station scenario, the present invention is also applicable to the V2X (Vehicle-to-Everything) scenario, the communication scenario between the terminal and the relay, and the relay and the base station, and obtains technical effects similar to those in the terminal and base station scenario. Further, although the original intention of the present invention is for the terminal and base station scenario, the present invention is also applicable to the IAB (Integrated Access and Backhaul) communication scenario, and obtains technical effects similar to those in the terminal and base station scenario. Furthermore, although the original intention of the present invention is for the terrestrial network (TN) scenario, the present invention is also applicable to the communication scenario of the non-terrestrial network (NTN), achieving similar technical effects in the TN scenario. In addition, the use of a unified solution for different scenarios also helps to reduce hardware complexity and cost.

[0006] As an embodiment, the interpretation of the terminology in the present invention refers to the definition of the 3GPP specification protocol TS36 series.

[0007] As an embodiment, the interpretation of the terms in the present invention refers to the definition of the TS38 series of specification protocols of 3GPP.

[0008] As an embodiment, the interpretation of the terms in the present invention refers to the definition of the TS37 series of specification protocols of 3GPP.

[0009] It should be noted that, in the absence of conflict, the embodiments and features in any node of the present invention may be applied to any other node. In the absence of conflict, the embodiments and features in the embodiments of the present invention may be arbitrarily combined with each other.

[0010] To solve the above technical problem, the present invention discloses a method in a first node for cell handover, comprising: receiving RRC signaling sent by a source cell, wherein the RRC signaling includes configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition;

[0011] In response to the first execution condition being satisfied, performing LTM cell switching;

[0012] Initiate a process of sending an SR to the first candidate target cell, wherein the process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH;

[0013] The process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the process of initiating an SR to the first candidate target cell is executed only when the LTM cell switching performed is an LTM cell switching without RACH.

[0014] In the technical solution provided by the present invention, the first node uses the received configuration information of the first candidate target cell to initiate a process of sending an SR to the first candidate target cell when performing LTM cell switching without RACH when the first execution condition is met. This solution does not need to initiate a random access process to the first candidate target cell, which can reduce latency.

[0015] In addition, as a candidate target cell for LTM cell switching (for example, the first candidate target cell), there is no need to permanently reserve physical downlink control channel (PDCCH) resources for terminal devices (such as the first node) that are capable of executing LTM without RACH, which can save downlink resources and is also beneficial to improving the PDCCH blind detection performance of other terminal devices.

[0016] As an embodiment, the problem to be solved by the present invention includes: how to control SR sending during LTM cell switching.

[0017] As an embodiment, whether to send the SR depends on whether the UE performs a RACH-based LTM cell handover or a RACH-free LTM cell handover.

[0018] As an embodiment, the benefits of the above method include: no need to monitor PDCCH resources in the candidate target cell, no need to send downlink control information to the candidate target cell, which is conducive to improving the reception performance of downlink control information of other nodes and improving resource utilization.

[0019] As an embodiment, the benefits of the above method include: avoiding triggering a random access process on the first candidate target cell and reducing the switching delay.

[0020] As an embodiment, the benefits of the above method include: LTM switching is performed only when the first execution condition is met, thereby increasing the success probability of LTM cell switching.

[0021] As an embodiment, the benefits of the above method include: the UE autonomously executes LTM, which is conducive to shortening the delay of SR sending.

[0022] As an embodiment, the benefits of the above method include: being conducive to improving UE service continuity.

[0023] As an embodiment, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0024] As an embodiment, the process of initiating sending an SR to the first candidate target cell includes: attempting to send an SR to the first candidate target cell.

[0025] As an embodiment, the sending of the SR is independent of whether there is data to be transmitted.

[0026] As an embodiment, the sending of the SR is independent of whether there is a Media Access Control (MAC) Control Element (CE) to be transmitted.

[0027] As an embodiment, whether to send the SR has nothing to do with the data to be transmitted and the MAC CE.

[0028] As an embodiment, the sending of the SR does not depend on whether there is data to be transmitted.

[0029] As an embodiment, the sending of the SR does not depend on whether there is a MAC CE to be transmitted.

[0030] As an embodiment, the sending of the SR does not depend on whether there is data to be transmitted, and does not depend on whether there is a MAC CE to be transmitted.

[0031] As an embodiment, the SR is not associated with any data.

[0032] As an embodiment, the SR is not associated with any MAC CE.

[0033] As an embodiment, the benefits of SR not relying on data transmission include: SR can be sent as early as possible without increasing delay by waiting until data is available.

[0034] As an embodiment, the sending of the SR to the first candidate target cell is performed after the LTM cell switching is started.

[0035] As an embodiment, the sending of the SR to the first candidate target cell is performed before the LTM cell switching is completed.

[0036] As an embodiment, the first node is not required to monitor the PDCCH of the first candidate target cell before the SR is sent.

[0037] As an embodiment, in response to receiving the PDCCH scheduling of the first candidate target cell, the process of sending the SR to the first candidate target cell is canceled.

[0038] As an embodiment, in response to receiving PDCCH scheduling of any target cell, the process of sending SR to the first candidate target cell is canceled.

[0039] As an embodiment, the SR is the first SR sent to the first candidate target cell.

[0040] As an embodiment, the SR is the first signal sent to the first candidate target cell.

[0041] According to one aspect of the present invention, the sending of the SR to the first candidate target cell includes: sending the SR to the first candidate target cell relies on synchronization with the first candidate target cell.

[0042] The solution of the present invention can effectively improve the probability of SR being successfully received, thereby improving the switching success rate.

[0043] According to one aspect of the present invention, along with the initiation of the process of sending the SR to the first candidate target cell, a timer is started; along with the expiration of the timer, the process of sending the SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back.

[0044] As an embodiment, the fallback execution of RACH-based LTM only includes contention-based random access (Contention Based Random Access, CBRA) LTM.

[0045] As an embodiment, the advantages of the above method include: stability and reliability, resource saving, and no switching time constraints.

[0046] As a variant embodiment, the fallback execution of RACH-based LTM includes CBRA-based LTM and CFRA-based LTM. The above method has the following advantages: high flexibility and shortened switching delay.

[0047] According to one aspect of the present invention, it includes: during the operation of the timer, after sending an SR to the first candidate target cell, stopping the timer; wherein the SR is the first uplink signal sent by the first node to the first candidate target cell.

[0048] The solution of the present invention is beneficial for terminal equipment to reduce resource overhead of maintaining a timer.

[0049] According to one aspect of the present invention, sending an SR to the first candidate target cell includes: when sending the SR fails, updating a counter; when the counter reaches a preset value, resetting the counter, canceling the process of sending the SR to the first candidate target cell, and falling back to executing the RACH-based LTM; wherein the counter is used to record the number of SR sending failures.

[0050] The solution of the present invention is beneficial to reducing the probability of LTM switching failure.

[0051] According to one aspect of the present invention, as a response to the failure to send SR to the first candidate target cell, a counter is updated; when the counter reaches a preset value, the counter is reset, and the process of sending SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back.

[0052] The solution of the present invention provides candidate SR resources before sending the SR, which is conducive to successfully sending the SR.

[0053] According to one aspect of the present invention, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0054] According to one aspect of the present invention, SR is sent to the first candidate target cell on one SR resource among at least one SR resource; wherein the configuration information of the first candidate target cell includes the at least one candidate SR configuration, and each of the candidate SR configurations is associated with at least one SR resource.

[0055] According to one aspect of the present invention, an RRC reconfiguration message of the first candidate target cell is received, the RRC reconfiguration message including deleting context information of the source cell and retaining configuration information of at least the first candidate target cell.

[0056] According to one aspect of the present invention, the first execution condition includes: the quality of the first candidate target cell is better than a given threshold; and the configuration information of the first candidate target cell includes the given threshold.

[0057] The solution of the present invention enables the terminal device to determine the switching form of LTM after receiving RRC signaling, which is helpful to reduce the complexity of the process.

[0058] According to one aspect of the present invention, it includes: after sending SR to the first candidate target cell, monitoring PDCCH, including: receiving scheduling information, and determining that the LTM cell switching is completed as a response to receiving the scheduling information.

[0059] To solve the above technical problems, the present invention discloses a method in a second node for cell switching, comprising: receiving an SR, wherein the SR depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the meaning of the SR depending on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH is that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH; wherein the SR is triggered by a first execution condition being satisfied, the first execution condition being included in the configuration information of a first candidate target cell, and the configuration information of the first candidate target cell being included in the RRC signaling from the source cell to the sender of the SR.

[0060] According to one aspect of the present invention, the configuration information of the first candidate target cell includes at least one candidate SR configuration, and each of the candidate SR configuration is associated with at least one SR resource; the receiving SR includes: receiving the SR on an SR resource among the at least one SR resource.

[0061] According to one aspect of the present invention, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0062] According to one aspect of the present invention, the reception of the SR triggers the second node to schedule the sender of the SR.

[0063] To solve the above technical problems, the present invention discloses a method in a third node for cell switching, comprising: sending RRC signaling to a first node, the RRC signaling including configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; wherein the first node performs LTM cell switching when the first execution condition is met; sending SR to the first candidate target cell, the sending of SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the sending of SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, meaning that: the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH.

[0064] According to one aspect of the present application, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0065] To solve the above technical problems, the present invention discloses a first node for cell switching, comprising: a receiver, receiving RRC signaling sent by a source cell, the RRC signaling including configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell including a first execution condition; a processor, executing LTM cell switching as a response to the first execution condition being satisfied; a transmitter, initiating a process of sending an SR (scheduling request) to the first candidate target cell, the process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; wherein, the process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, meaning that: only when the LTM cell switching performed is an LTM cell switching without RACH, the process of initiating SR to the first candidate target cell is executed.

[0066] To solve the above technical problems, the present invention discloses a second node for cell switching, comprising: a receiver, receiving an SR, wherein the SR depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the meaning of the SR depending on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH is that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH; wherein the SR is triggered by a first execution condition being satisfied, the first execution condition being included in the configuration information of a first candidate target cell, and the configuration information of the first candidate target cell being included in the RRC signaling from the source cell to the sender of the SR.

[0067] In order to solve the above technical problem, the present invention discloses a third node for cell switching, comprising:

[0068] A transmitter sends an RRC signaling to a first node, wherein the RRC signaling includes configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; wherein the first node performs an LTM cell handover when the first execution condition is met; and an SR is sent to the first candidate target cell, wherein the sending of the SR to the first candidate target cell depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH;

[0069] The meaning of sending the SR to the first candidate target cell depending on whether the performed LTM cell handover is a RACH-based LTM cell handover or a RACH-free LTM cell handover is that the SR is sent only when the performed LTM cell handover is a RACH-free LTM cell handover.

[0070] As an embodiment, compared with the traditional solution, the present invention has the following advantages:

[0071] (1) Determining whether to send an SR depends on whether the UE performs a RACH-based LTM cell handover or a RACH-free LTM cell handover. This has many advantages.

[0072] (2) Saving PDCCH resources is beneficial to improving PDCCH reception performance;

[0073] (3) Avoid triggering a random access process on the first candidate target cell to reduce handover delay;

[0074] (4) LTM switching is performed only when the first execution condition is met, which increases the probability of LTM cell success, helps improve the robustness of LTM, and avoids disconnection;

[0075] (5) UE autonomously executes LTM, which helps to shorten the delay of LTM cell handover;

[0076] (6) It is conducive to improving UE service continuity. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments thereof with reference to the following drawings:

[0078] Figure 1 A schematic diagram of the process of LTM switching according to an embodiment of the present invention is shown;

[0079] Figure 2 A schematic diagram showing a network architecture according to an embodiment of the present invention is shown;

[0080] Figure 3 A schematic diagram showing an embodiment of a radio protocol architecture of a user plane and a control plane according to an embodiment of the present invention;

[0081] Figure 4 A schematic diagram of hardware modules of a communication device according to an embodiment of the present invention is shown;

[0082] Figure 5 A wireless signal transmission flow chart according to an embodiment of the present invention is shown;

[0083] Figure 6 A wireless signal transmission flow chart according to another embodiment of the present invention is shown;

[0084] Figure 7 A wireless signal transmission flow chart according to another embodiment of the present invention is shown;

[0085] Figure 8 An example of a wireless signal transmission flow chart according to another embodiment of the present invention is provided;

[0086] Fig. 9 Another wireless signal transmission flow chart according to an embodiment of the present invention is illustrated;

[0087] Fig.10 A structural block diagram of a processing device used in a first node according to an embodiment of the present invention is shown;

[0088] Fig.11 A structural block diagram of a processing device used in a second node according to an embodiment of the present invention is shown;

[0089] Fig.12 A structural block diagram of a processing device used in a third node according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0090] As mentioned in the background technology, in the prior art, there are many technical implementation forms of mobility management such as cell switching, including L3 switching and L1 / L2 switching below L3. The development of conditional switching (CHO) and other conditional migration processes (CPAC, SCPAC) enables the switching process to be executed without prior signaling interaction with the source cell, and high robustness can also be achieved. The LTM technology introduced in Rel-18 provides a shorter interruption time, but its robustness is not as good as the conditional L3 mobility process. It is necessary to enhance this function during the NR evolution process so that the wireless communication system can benefit from high robustness and short interruption time.

[0091] Currently, the network device can provide one or more candidate configurations to the terminal device (such as UE), and each candidate configuration can include one or more cells. The network device can subsequently control the terminal device to change in multiple candidate configurations through L1 or L2 signaling, that is, cell change control signaling, to achieve a serving cell change. This process can be called an LTM process.

[0092] The general process of LTM is as follows: First, the terminal device in the RRC connection state reports the measurement results to the source cell. If the terminal device supports LTM, the source cell can send an LTM cell switching request to the candidate target cell. After the candidate target cell sends an LTM cell switching request response to the source cell and sends the configuration information of the corresponding LTM candidate target cell to the source cell, the source cell can send RRC reconfiguration information to the terminal device. Among them, the RRC reconfiguration information can carry the configuration information of the LTM candidate target cell.

[0093] After receiving the configuration information of the LTM candidate target cell, the terminal device sends an RRC reconfiguration completion message to the source cell. Then, the terminal device performs downlink synchronization and uplink synchronization for each candidate target cell.

[0094] Among them, in the process of performing uplink synchronization for each candidate target cell, if the RRC reconfiguration information indicates that the terminal device itself measures the timing advance (Timing Advance, TA), then the terminal device can measure the timing advance of the source cell, and determine the timing advance of the candidate target cell based on the reception time difference between the source cell and the candidate cell; or, the source cell triggers CFRA through the PDCCH order to obtain the timing advance of the candidate target cell, and the terminal device initiates CFRA to the candidate target cell to obtain the timing advance of the candidate target cell, and then the source cell determines the validity of the timing advance.

[0095] After the uplink synchronization is completed, the terminal device performs L1 measurement on the source cell and the candidate target cell to obtain the L1 measurement result, and then the terminal device reports the L1 measurement result to the source cell. After the terminal device reports the L1 measurement result to the source cell, the source cell can determine the candidate target cell according to the L1 measurement result. The source cell sends an LTM switching instruction to the terminal device.

[0096] The LTM switching instruction may be a MAC CE. The MAC CE may include at least the following information: TA, transmission configuration indication state (TCI State) sequence number (IDentity, ID), CFRA resource information, and LTM candidate primary cell configuration information identifier. For TA, if the source cell determines that the TA previously acquired by the terminal device is still in a valid state, then the TA may be included in the MAC CE.

[0097] Further, the terminal device disconnects from the source cell and initiates a random access process to the candidate target cell. When the terminal device receives the MAC CE, if the MAC CE carries the TA, or the terminal device detects the TA by itself, the terminal device initiates a handover without random access to the candidate target cell, that is, the terminal device sends an uplink signaling or the first uplink data packet to the candidate target cell to indicate to the candidate target cell that it has accessed the candidate target cell to complete the LTM cell handover.

[0098] For RACH-less scenarios, when changing cells, the terminal device may not initiate a random access process in the candidate target cell. Considering that LTM is mainly for shorter interruption time, Rel-18 supports RACH-free process. If NR supports conditional LTM without RACH in subsequent evolution, it will cause information deviation between the network and UE. The network does not know when the UE will switch, causing the network to have to reserve resources all the time, which will result in resource waste; if resources are not reserved all the time, robustness issues will arise.

[0099] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be noted that the embodiments of the present invention and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0100] Example 1

[0101] Embodiment 1 illustrates a schematic diagram of the LTM switching process according to an embodiment of the present invention, as shown in the attached Figure 1 Attached Figure 1In the figure, each box represents a step. It should be emphasized that the order of the boxes in the figure does not represent the temporal relationship between the steps represented.

[0102] In Embodiment 1, the first node in the present invention may be a terminal device, such as a UE, etc. The method for running the first node is as follows:

[0103] Step S101, receiving RRC signaling sent by a source cell, wherein the RRC signaling includes configuration information of a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition;

[0104] Step S102, in response to the first execution condition being satisfied, executing LTM cell switching;

[0105] Step S103, initiating a process of sending an SR to the first candidate target cell, wherein the process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH;

[0106] Among them, the meaning of sending SR to the first candidate target cell depends on whether the performed LTM cell switching is a RACH-based LTM cell switching or a RACH-free LTM cell switching is: only when the performed LTM cell switching is a RACH-free LTM cell switching, the process of sending SR to the first candidate target cell is initiated.

[0107] As an embodiment, the meaning of the SR being sent only when the LTM cell switch performed is an LTM cell switch without RACH is: before the LTM cell switch is completed, the process of sending the SR to the first candidate target cell is executed only when the LTM cell switch performed is an LTM cell switch without RACH.

[0108] Specifically, the first node receives RRC signaling sent by a source cell in step S101. The source cell may be a serving cell of the first node. The RRC signaling is an RRC message.

[0109] As an embodiment, the RRC message is a downlink (Downlink, DL) RRC message.

[0110] As an embodiment, the RRC message is a sidelink (Sidelink, SL) RRC message.

[0111] As an embodiment, the RRC message is a UE-specific RRC message. The UE-specific RRC message refers to an RRC message transmitted via a dedicated control channel (Dedicated Control Channel, DCCH).

[0112] As an embodiment, the UE-specific RRC message refers to: an RRC message transmitted through a SCCH (Dedicated Control Channel).

[0113] As an embodiment, the UE-specific RRC message refers to: an RRC message transmitted through signaling radio bearer 1 (Signalling radiobearer1, SRB1) or signaling radio bearer 3 (Signalling radio bearer 3, SRB3).

[0114] As an embodiment, the UE-specific RRC message refers to: an RRC message transmitted via SL-SRB3; or a unicast RRC message.

[0115] As an embodiment, the RRC message is any one of an RRCReconfiguration message, an RRCResume message, an RRCReestablishment message, and an RRCReconfigurationSidelink message.

[0116] As an embodiment, the RRC message is a DLInformationTransferMRDC message, and the DLInformationTransferMRDC message includes an RRCReconfiguration message.

[0117] As an embodiment, the RRC message includes one or more RRC information blocks. In a specific implementation, the RRC information block is an RRC container (contenter), or an RRC IE (Information Element), or an RRC message.

[0118] As an embodiment, the RRC information block includes at least one RRC IE and / or at least one RRC field.

[0119] As an embodiment, the RRC information block includes configuration information of at least one candidate target cell, wherein the configuration information of the at least one candidate target cell includes the configuration information of the first candidate target cell.

[0120] As a sub-embodiment of this embodiment, the RRC information block includes configuration information of only one candidate target cell. In this case, the RRC information block includes configuration information of the first candidate target cell.

[0121] Alternatively, the RRC information block includes configuration information of each candidate target cell in a cell group to which a candidate target cell belongs. In this case, the RRC information block includes configuration information of each candidate target cell in the cell group to which the first candidate target cell belongs.

[0122] As an embodiment, the RRC information block includes configuration information of at least one candidate target cell, and the first candidate target cell is one of the at least one candidate target cell.

[0123] As an embodiment, the configuration information of the first candidate target cell includes configuration information of the physical layer of the first candidate target cell.

[0124] As an embodiment, the configuration information of the first candidate target cell includes the C-RNTI of the first node in the first candidate target cell.

[0125] As an embodiment, the configuration information of the first candidate target cell includes public configuration information of the first candidate target cell.

[0126] As an embodiment, the configuration information of the first candidate target cell includes at least part of the domain in the ServingCellConfigCommon IE.

[0127] As an embodiment, the configuration information of the first candidate target cell includes the PCI of the first candidate target cell.

[0128] As an embodiment, the configuration information of the first candidate target cell includes a downlink common configuration (DownlinkConfigCommon) of the first candidate target cell and / or an uplink common configuration (UplinkConfigCommon) of the first candidate target cell.

[0129] As an embodiment, the configuration information of the first candidate target cell includes the period of the SSB of the first candidate target cell.

[0130] As an embodiment, the configuration information of the first candidate target cell includes the PBCH of the first candidate target cell.

[0131] As an embodiment, the RRC information block is a CellGroupConfig IE; or includes a cellGroupId, and the cellGroupId indicates the cell group to which the first candidate target cell belongs.

[0132] As an embodiment, the RRC information block is associated with a first candidate configuration index, and the first candidate configuration index indicates the first candidate target cell.

[0133] As an embodiment, the RRC message includes a first candidate configuration index, and the first candidate configuration index indicates the first candidate target cell. The first candidate configuration index can be used to indicate the first candidate target cell, or used to indicate the first candidate target cell in an LTM command, or used to indicate the first candidate target cell in a PDCCH order.

[0134] In a specific implementation, the configuration information of the first candidate target cell may include a first execution condition. In one embodiment, the first execution condition refers to satisfying an execution condition for LTM cell switching.

[0135] For example, the first execution condition includes: the signal strength or channel quality of the source cell is lower than or equal to a preset first threshold.

[0136] For another example, the first execution condition includes: the signal strength or channel quality of the source cell is lower than or equal to a preset first threshold, and the signal strength or channel quality of the candidate target cell is higher than or equal to a preset second threshold.

[0137] As an embodiment, the RRC message may further include the preset first threshold, and the preset second threshold, for example, is carried by the RRC information block.

[0138] As a variation example, the preset first threshold and the preset second threshold are default or are sent by other RRC messages.

[0139] As an embodiment, the RRC information block is configured with an event in which the LTM is executed.

[0140] As an embodiment, the RRC information block includes a newUE-Identity field, and the newUE-Identity field indicates the C-RNTI of the first node in the first candidate target cell.

[0141] As an embodiment, the RRC information block includes a ServingCellConfigCommon IE, and the ServingCellConfigCommon IE includes the PhysCellId of the first candidate target cell.

[0142] As an embodiment, the RRC information block includes a CellGroupConfig IE, and the CellGroupConfig IE includes the ServingCellConfigCommon IE.

[0143] In another embodiment, the RRC information block includes a SpCellConfig field, and the SpCellConfig field includes the ServingCellConfigCommon IE. Alternatively, the RRC information block includes a ReconfigurationWithSync field, and the ReconfigurationWithSync field includes the ServingCellConfigCommon IE.

[0144] As a sub-embodiment of this embodiment, the ServingCellConfigCommon IE includes a DownlinkConfigCommon IE or an UplinkConfigCommon IE.

[0145] As a sub-embodiment of this embodiment, the ServingCellConfigCommon IE includes an n-TimingAdvanceOffset field or includes an ssb-PositionsInBurst field.

[0146] As a sub-embodiment of this embodiment, the ServingCellConfigCommon IE includes an ss-PBCH-BlockPower field.

[0147] As an embodiment, after the RRC signaling is received, the configuration information of each candidate target cell included therein is stored. For example, the configuration information of the first candidate target cell is stored in a first variable.

[0148] During specific implementation, the first variable may be VarConditionalReconfig.

[0149] As an embodiment, the name of the first variable includes at least one of Var or LTM or Mobility or L1 or L2.

[0150] As a sub-embodiment of this embodiment, in response to the RRC message being received, the RRC information block is stored or updated in the first variable.

[0151] As a sub-embodiment of this embodiment, as a response to the RRC message being received, the configuration information of the candidate target cell is stored or updated in the first variable.

[0152] As a sub-embodiment of this embodiment, in response to the RRC message being received, the configuration information of each candidate target cell in the RRC information block is stored or updated in the first variable.

[0153] As an embodiment, the first variable may be used for LTM, for example, for RACH-based LTM, or for RACH-free LTM.

[0154] In step S102, when the first node meets the first execution condition, LTM cell switching may be performed.

[0155] As an embodiment, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0156] In a specific implementation, the RRC signaling includes executing RACH-based LTM configuration information, and the first node may trigger a random access process on the first candidate target cell based on the configuration information, wherein the random access process is a CFRA, or the random access process is a CBRA.

[0157] As a variant implementation, the first execution condition includes a condition for executing LTM without RACH, and the LTM switching is LTM cell switching without RACH.

[0158] In step S103, depending on whether the LTM cell handover performed is a RACH-based LTM cell handover or a RACH-free LTM cell handover, the first node may send an SR to the first candidate target cell.

[0159] In a specific implementation, the first node sends the SR only when the LTM cell handover performed is an LTM cell handover without RACH.

[0160] In specific implementation, the purpose of sending the SR is not to request uplink resources.

[0161] In a specific implementation, the first candidate target cell that receives the SR may deem that the first node that issues the SR has successfully completed the LTM cell handover.

[0162] In specific implementation, the purpose of sending the SR is to complete the LTM switching.

[0163] For example, the purpose of sending the SR is to complete LTM without RACH.

[0164] For another example, the purpose of sending the SR is to inform the first candidate target cell that the first node is performing LTM without RACH.

[0165] As an embodiment, the sending of the SR is independent of whether there is data to be transmitted.

[0166] As an embodiment, the sending of the SR is independent of whether there is a MAC CE to be transmitted.

[0167] As an embodiment, whether to send the SR has nothing to do with the data to be transmitted and the MAC CE.

[0168] As an embodiment, the sending of the SR does not depend on whether there is data to be transmitted.

[0169] As an embodiment, the sending of the SR does not depend on whether there is a MAC CE to be transmitted.

[0170] As an embodiment, the sending of the SR does not depend on whether there is data to be transmitted, and does not depend on whether there is a MAC CE to be transmitted.

[0171] As an embodiment, the SR is not associated with any data.

[0172] As an embodiment, the SR is not associated with any MAC CE.

[0173] As an embodiment, the first node is not required to monitor the PDCCH of the first candidate target cell before the SR is sent.

[0174] As an embodiment, in response to receiving the PDCCH scheduling of the first candidate target cell, the process of sending the SR to the first candidate target cell is canceled.

[0175] As an embodiment, in response to receiving PDCCH scheduling of any candidate target cell, the process of sending SR to the first candidate target cell is canceled.

[0176] As an embodiment, the SR is the first SR sent to the first candidate target cell.

[0177] As an embodiment, the SR is the first signal sent to the first candidate target cell.

[0178] In a specific implementation, the first node may determine when to send the SR to the first candidate target cell based on the physical layer synchronization of the first candidate target cell. The first node triggers the SR after completing physical layer downlink synchronization and uplink synchronization with the first candidate target cell, and sends the SR to the first candidate target cell.

[0179] As an embodiment, the configuration information of the first candidate target cell is used to trigger the SR.

[0180] As an embodiment, at least configuration information in the configuration information of the first candidate target cell is used to trigger the SR.

[0181] As an embodiment, the first node determines in step S102 to execute LTM without RACH before executing step S103 to trigger the SR.

[0182] As an embodiment, the sending of the SR to the first candidate target cell is performed after the LTM cell switching is started.

[0183] As an embodiment, the sending of the SR to the first candidate target cell is performed before the LTM cell switching is completed.

[0184] As an embodiment, the sending of the SR to the first candidate target cell is performed during the LTM cell handover. At this time, step S102 and step S103 are performed in parallel.

[0185] As an embodiment, based on the configuration information of the first candidate target cell, the RRC sublayer of the first node sends an indication to the lower layer of the first node; for example, an indication is sent to the MAC sublayer of the first node, and the MAC sublayer triggers the SR in response to the indication.

[0186] As an embodiment, no uplink data is used to trigger the SR.

[0187] As a sub-embodiment of this embodiment, the SR is triggered when there is no uplink data.

[0188] As a sub-embodiment of this embodiment, when the SR is triggered, there is no uplink data.

[0189] As an embodiment, the SR is triggered regardless of whether there is uplink data.

[0190] As a sub-embodiment of this embodiment, when the SR is triggered, there is no uplink data.

[0191] As a sub-embodiment of this embodiment, when the SR is triggered, there is uplink data.

[0192] As an embodiment, the uplink data includes a PDU or SDU cached in a PDCP entity or an RLC entity.

[0193] As an embodiment, the first node may autonomously acquire the timing of the candidate target cell to complete uplink synchronization in advance.

[0194] In specific implementation, during the uplink synchronization process for the first candidate target cell, if the RRC message indicates that the first node itself measures the timing advance, then the first node can measure the timing advance of the source cell and determine the timing advance of the first candidate target cell based on the reception time difference between the source cell and the first candidate target cell.

[0195] As an embodiment, the first node may start a timer when triggering the SR; when the timer expires, the process of sending the SR to the first candidate target cell is canceled, and the execution of the RACH-based LTM is rolled back.

[0196] As an embodiment, the fallback execution of RACH-based LTM only includes LTM of contention-based random access CBRA.

[0197] As a variant embodiment, the fallback execution of RACH-based LTM includes CBRA-based LTM and CFRA-based LTM. The advantage is that the flexibility is high and the switching delay is shortened.

[0198] As another variation, the first node may update a counter when sending the SR fails; when the counter reaches a preset value, the counter may be reset, and the process of sending the SR to the first candidate target cell may be canceled, and the RACH-based LTM may be rolled back; wherein the counter is used to record the number of SR sending failures.

[0199] In a specific implementation, if the initial value of the counter for recording the number of SR sending failures is 0, when sending the SR fails, the counter can be increased by 1. When the counter reaches a preset value, such as a maximum value, the counter can be reset, and the sending of SR to the first candidate target cell is stopped. In addition, this LTM cell handover no longer executes LTM without RACH, and falls back to executing LTM based on RACH.

[0200] In a variant implementation, if the initial value of the counter for recording the number of SR sending failures is a preset value (e.g., a non-zero maximum value), when the first node fails to send the SR, the counter may be reduced by 1. When the counter reaches 0, the counter may be reset to the preset value, and the sending of SR to the first candidate target cell may be stopped. In addition, this LTM cell handover no longer executes LTM without RACH, and falls back to executing LTM based on RACH.

[0201] As an embodiment, the first node may cancel the timer after successfully sending the SR to the first candidate target cell during the operation of the timer. The SR is the first uplink signal sent by the first node to the first candidate target cell. As a variation, the first node may stop the timer after successfully sending the SR to the first candidate target cell during the operation of the timer.

[0202] As an embodiment, the configuration information of the first candidate target cell may include one candidate SR configuration or multiple candidate SR configurations, each of the candidate SR configurations being associated with at least one SR resource. The first lesson may send an SR to the first candidate target cell on one SR resource of the at least one SR resource.

[0203] As an embodiment, the candidate SR configuration can be used for the SR.

[0204] As an embodiment, the SR may use the candidate SR configuration.

[0205] As an embodiment, any valid Physical Uplink Control Channel (PUCCH) resource in the candidate SR configuration is used for the SR.

[0206] As an embodiment, any valid SR resource in the candidate SR configuration is used for the SR.

[0207] As an embodiment, the candidate SR configurations include no more than maxNrofSR-ConfigPerCellGroup candidate SR configurations.

[0208] As an embodiment, the candidate SR configuration is configured to the first node.

[0209] As an embodiment, the candidate SR configurations are configured in the same MAC entity.

[0210] As an embodiment, the candidate SR configuration is configured in the first candidate target cell.

[0211] As an embodiment, the candidate SR configuration is configured for the first candidate target cell.

[0212] As an embodiment, the candidate SR configuration is configured to the cell group to which the first candidate target cell belongs.

[0213] As an embodiment, the candidate SR configuration is configured to the MAC entity to which the cell group to which the first candidate target cell belongs belongs.

[0214] As an embodiment, the candidate SR configuration is configured to a BWP (bandwidth part) of the first candidate target cell.

[0215] As an embodiment, the candidate SR configuration is indexed by a SchedulingRequestId.

[0216] As an embodiment, the candidate SR configuration is associated with PUCCH resources.

[0217] As an embodiment, the candidate SR configuration is indicated by an index of at least one PUCCH resource.

[0218] As an embodiment, the candidate SR configuration includes an index of a PUCCH resource.

[0219] As an embodiment, the candidate SR configuration includes PUCCH resources.

[0220] As an embodiment, the SR resources are physical layer resources, PUCCH resources, and / or PUCCH resources used for SR.

[0221] As an embodiment, the SR resource refers to the PUCCH resource indexed by SchedulingRequestResourceId.

[0222] As an embodiment, when the L1 / L2 signaling is received, the first cell is a PCell, and the first candidate target cell is a secondary cell in the cell group to which the first cell belongs.

[0223] As an embodiment, the source cell is a PSCell, and the first candidate target cell is a secondary cell in the cell group to which the source cell belongs.

[0224] As an embodiment, the source cell is a PCell, and the first candidate target cell is a SCell.

[0225] As an embodiment, the source cell is a PSCell, and the first candidate target cell is an SCell.

[0226] As an embodiment, the source cell is a PCell, and the first candidate target cell is a PSCell.

[0227] As an embodiment, the source cell is a PCell, and the first candidate target cell is a secondary cell in an MCG.

[0228] As an embodiment, the source cell is a PSCell, and the first candidate target cell is a secondary cell in the SCG.

[0229] After successfully receiving the SR, the first candidate target cell becomes a new serving cell of the first node. The first candidate target cell may send a signaling to the first node, and the signaling may include deleting the context information of the source cell. After receiving the signaling, the first node may delete the context information of the source cell. In a specific implementation, the signaling may be a high-level signaling or a non-high-level signaling, such as an RRC reconfiguration message, a MAC CE.

[0230] As an embodiment, sending SR in the present application refers to sending a signal indicating SR.

[0231] As a sub-embodiment of this embodiment, the signal indicating the SR is a signal of the physical layer.

[0232] As a sub-embodiment of this embodiment, the signal indicating the SR is a signal on the PUCCH.

[0233] As an embodiment, sending an SR signal in the present application refers to sending a signal indicating SR.

[0234] As a sub-embodiment of this embodiment, the signal indicating the SR is a signal of the physical layer.

[0235] As a sub-embodiment of this embodiment, the signal indicating the SR is a signal on the PUCCH.

[0236] Example 2

[0237] Embodiment 2 illustrates a schematic diagram of a network architecture according to an embodiment of the present invention, as shown in the attached figure. Figure 2 shown. Figure 2A diagram illustrating a network architecture 200 for NR 5G, LTE, and LTE-A (Long-Term Evolution Advanced) systems. The NR 5G, LTE, or LTE-A network architecture 200 may be referred to as 5GS (5G System) / EPS (Evolved Packet System) 200 or some other suitable term. The 5GS / EPS 200 may include one or more UEs 201, NG-RAN (Next Generation Radio Access Network) 202, 5GC (5G Core Network) / EPC (Evolved Packet Core) 210, HSS (Home Subscriber Server) / UDM (Unified Data Management) 220, and Internet services 230. The 5GS / EPS may be interconnected with other access networks, but these entities / interfaces are not shown for simplicity. As shown, 5GS / EPS provides packet switching services, however, those skilled in the art will readily appreciate that the various concepts presented throughout the present invention can be extended to networks providing circuit switching services or other cellular networks. NG-RAN includes NR Node B (gNB) 203 and other gNBs 204. gNB 203 provides user and control plane protocol terminations toward UE 201. gNB 203 can be connected to other gNBs 204 via an Xn interface (e.g., backhaul). gNB 203 may also be referred to as a base station, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (Basic Service Set, BSS), an extended service set (Extended Service Set, ESS), a TRP (Transmission Reception Point, sending and receiving node) or some other suitable terminology. In a NTN (Non Terrestrial Network, non-terrestrial / satellite network) network, gNB 203 may be a satellite, an aircraft, or a ground base station relayed by a satellite. gNB 203 provides an access point to 5GC / EPC 210 for UE 201.Examples of UE 201 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, drones, aircraft, narrowband Internet of Things devices, machine type communication devices, land vehicles, cars, vehicle-mounted devices, vehicle-mounted communication units, wearable devices, or any other similar functional devices. Those skilled in the art may also refer to UE 201 as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable term. gNB203 is connected to 5GC / EPC210 via S1 / NG interface. 5GC / EPC210 includes MME (Mobility Management Entity) / AMF (Authentication Management Field) / SMF (Session Management Function) 211, other MME / AMF / SMF214, S-GW (Service Gateway) / UPF (User Plane Function) 212 and P-GW (Packet Data Network Gateway) / UPF213. MME / AMF / SMF211 is the control node that handles signaling between UE201 and 5GC / EPC210. ​​In general, MME / AMF / SMF211 provides bearer and connection management. All user IP (Internet Protocol) packets are transmitted through S-GW / UPF212, which itself is connected to P-GW / UPF213. P-GW provides UE IP address allocation and other functions. P-GW / UPF213 is connected to Internet service 230. Internet service 230 includes operator-corresponding Internet protocol services, which may specifically include Internet, Intranet, IMS (IP Multimedia Subsystem) and PS (Packet Switching) streaming services.

[0238] As an embodiment, the UE201 corresponds to the first node in the present invention.

[0239] As an embodiment, the gNB203 corresponds to the second node and / or the third node in the present invention.

[0240] As an embodiment, the gNB203 is a macro cell base station.

[0241] As an embodiment, the gNB203 is a micro cell base station.

[0242] As an embodiment, the gNB203 is a pico cell base station.

[0243] As an embodiment, the gNB203 is a home base station (Femtocell).

[0244] As an embodiment, the gNB203 is a base station device that supports large delay difference.

[0245] As an embodiment, the gNB203 is a flying platform device.

[0246] As an embodiment, the gNB203 is a satellite device.

[0247] As an embodiment, the gNB203 is a testing device (e.g., a transceiver that simulates some functions of a base station, a signaling tester).

[0248] As an embodiment, the other gNB204 is a macro cell base station.

[0249] As an embodiment, the other gNB204 is a micro cell base station.

[0250] As an embodiment, the other gNB204 is a pico cell base station.

[0251] As an embodiment, the other gNB204 is a home base station (Femtocell).

[0252] As an embodiment, the other gNB204 is a base station device that supports a large delay difference.

[0253] As an embodiment, the other gNB204 is a flying platform device.

[0254] As an embodiment, the other gNB204 is a satellite device.

[0255] As an embodiment, the other gNB204 is a test device (e.g., a transceiver that simulates some functions of a base station, a signaling tester).

[0256] As an embodiment, the wireless link from the UE201 to the gNB203 is an uplink, and the uplink is used to perform uplink transmission.

[0257] As an embodiment, the wireless link from the gNB203 to the UE201 is a downlink, and the downlink is used to perform downlink transmission.

[0258] As an embodiment, the UE201 and the gNB203 are connected via a Uu interface.

[0259] Example 3

[0260] Embodiment 3 shows a schematic diagram of an embodiment of a wireless protocol architecture of a user plane and a control plane according to the present invention, as shown in the attached figure. Figure 3 shown. Figure 3 is a schematic diagram illustrating an embodiment of a radio protocol architecture for a user plane 350 and a control plane 300, Figure 3The radio protocol architecture for the control plane 300 is shown in three layers: L1, L2, and L3. The L1 layer is the lowest layer and implements various PHY (physical layer) signal processing functions. The L1 layer will be referred to as PHY301 in this article. The L2 layer 305 is above PHY301 and includes a MAC (Medium Access Control) sublayer 302, an RLC (Radio Link Control) sublayer 303, and a PDCP (Packet Data Convergence Protocol) sublayer 304. The PDCP sublayer 304 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 304 also provides security by encrypting data packets, and provides inter-zone mobility support. The RLC sublayer 303 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to HARQ (Hybrid Automatic Repeat Request). The MAC sublayer 302 provides multiplexing between logical and transport channels. The MAC sublayer 302 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell. The MAC sublayer 302 is also responsible for HARQ operations. The RRC (Radio Resource Control) sublayer 306 in the L3 layer in the control plane 300 is responsible for obtaining radio resources (i.e., radio bearers) and using RRC signaling to configure the lower layers. The radio protocol architecture of the user plane 350 includes an L1 layer and an L2 layer. In the user plane 350, the radio protocol architecture is substantially the same as the corresponding layers and sublayers in the control plane 300 for the physical layer 351, the PDCP sublayer 354 in the L2 layer 355, the RLC sublayer 353 in the L2 layer 355, and the MAC sublayer 352 in the L2 layer 355, but the PDCP sublayer 354 also provides header compression for upper layer data packets to reduce radio transmission overhead. The L2 layer 355 in the user plane 350 also includes a SDAP (Service Data Adaptation Protocol) sublayer 356. The SDAP sublayer 356 is responsible for mapping between QoS flows and data radio bearers (DRBs) to support service diversity.

[0261] As an example, Figure 3 The wireless protocol architecture in is applicable to the first node in the present invention.

[0262] As an example, Figure 3 The wireless protocol architecture in is applicable to the second node in the present invention.

[0263] As an example, Figure 3 The wireless protocol architecture in is applicable to the third node in the present invention.

[0264] As an embodiment, the RRC message in the present invention is generated in the RRC306.

[0265] As an embodiment, the LTM signaling in the present invention is generated by the MAC302 or MAC352.

[0266] As an embodiment, the LTM signaling in the present invention is generated in the PHY301 or PHY351.

[0267] As an embodiment, the process of sending SR to the first candidate target cell in the present invention is generated in the MAC302 or MAC352.

[0268] As an embodiment, the process of sending SR to the first candidate target cell in the present invention is canceled in MAC302 or MAC352.

[0269] As an embodiment, the SR signal in the present invention is generated by the PHY301 or PHY351.

[0270] Example 4

[0271] Embodiment 4 illustrates a hardware module schematic diagram of a communication device according to an embodiment of the present invention, as shown in the attached figure. Figure 4 shown. Figure 4 is a block diagram of a first communication device 450 and a second communication device 410 communicating with each other in an access network.

[0272] The first communication device 450 includes a controller / processor 459, a memory 460, a data source 467, a transmit processor 468, a receive processor 456, a multi-antenna transmit processor 457, a multi-antenna receive processor 458, a transmitter / receiver 454 and an antenna 452.

[0273] The second communication device 410 includes a controller / processor 475, a memory 476, a data source 477, a receive processor 470, a transmit processor 416, a multi-antenna receive processor 472, a multi-antenna transmit processor 471, a transmitter / receiver 418 and an antenna 420.

[0274] In the transmission from the second communication device 410 to the first communication device 450, at the second communication device 410, the upper layer data packets from the core network or the upper layer data packets from the data source 477 are provided to the controller / processor 475. The core network and the data source 477 represent all the protocol layers above the L2 layer. The controller / processor 475 implements the functionality of the L2 layer. In the transmission from the second communication device 410 to the first communication device 450, the controller / processor 475 provides header compression, encryption, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation to the first communication device 450 based on various priority metrics. The controller / processor 475 is also responsible for the retransmission of lost packets and signaling to the first communication device 450. The transmit processor 416 and the multi-antenna transmit processor 471 implement various signal processing functions for the L1 layer (i.e., the physical layer). The transmit processor 416 implements coding and interleaving to facilitate forward error correction (FEC) at the second communication device 410, as well as mapping of signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The multi-antenna transmit processor 471 performs digital spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing on the coded and modulated symbols to generate one or more spatial streams. The transmit processor 416 then maps each spatial stream to a subcarrier, multiplexes it with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then uses an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain multi-carrier symbol stream. The multi-antenna transmit processor 471 then performs a transmit analog precoding / beamforming operation on the time-domain multi-carrier symbol stream. Each transmitter 418 converts the baseband multi-carrier symbol stream provided by the multi-antenna transmit processor 471 into a radio frequency stream, and then provides it to a different antenna 420.

[0275] In the transmission from the second communication device 410 to the first communication device 450, at the first communication device 450, each receiver 454 receives a signal through its corresponding antenna 452. Each receiver 454 recovers the information modulated onto the RF carrier and converts the RF stream into a baseband multi-carrier symbol stream and provides it to the receiving processor 456. The receiving processor 456 and the multi-antenna receiving processor 458 implement various signal processing functions of the L1 layer. The multi-antenna receiving processor 458 performs a receiving analog precoding / beamforming operation on the baseband multi-carrier symbol stream from the receiver 454. The receiving processor 456 uses a fast Fourier transform (FFT) to convert the baseband multi-carrier symbol stream after the receiving analog precoding / beamforming operation from the time domain to the frequency domain. In the frequency domain, the physical layer data signal and the reference signal are demultiplexed by the receiving processor 456, wherein the reference signal will be used for channel estimation, and the data signal is recovered after multi-antenna detection in the multi-antenna receiving processor 458 to any spatial stream destined for the first communication device 450. The symbols on each spatial stream are demodulated and recovered in the receiving processor 456, and soft decisions are generated. The receiving processor 456 then decodes and deinterleaves the soft decisions to recover the upper layer data and control signals transmitted by the second communication device 410 on the physical channel. The upper layer data and control signals are then provided to the controller / processor 459. The controller / processor 459 implements the functions of the L2 layer. The controller / processor 459 may be associated with a memory 460 that stores program codes and data. The memory 460 may be referred to as a computer-readable medium. In the transmission from the second communication device 410 to the first communication device 450, the controller / processor 459 provides multiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover the upper layer data packets from the second communication device 410. The upper layer data packets are then provided to all protocol layers above the L2 layer. Various control signals may also be provided to the L3 for L3 processing.

[0276] In the transmission from the first communication device 450 to the second communication device 410, at the first communication device 450, the upper layer data packets are provided to the controller / processor 459 using the data source 467. The data source 467 represents all the protocol layers above the L2 layer. Similar to the transmission function at the second communication device 410 described in the transmission from the second communication device 410 to the first communication device 450, the controller / processor 459 implements header compression, encryption, packet segmentation and reordering, and multiplexing between logical and transport channels, and implements L2 layer functions for user plane and control plane. The controller / processor 459 is also responsible for the retransmission of lost packets and signaling to the second communication device 410. The transmit processor 468 performs modulation mapping and channel coding processing, and the multi-antenna transmit processor 457 performs digital multi-antenna spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing. Then, the transmit processor 468 modulates the generated spatial stream into a multi-carrier / single-carrier symbol stream, which is then provided to different antennas 452 via the transmitter 454 after analog precoding / beamforming operations in the multi-antenna transmit processor 457. Each transmitter 454 first converts the baseband symbol stream provided by the multi-antenna transmit processor 457 into a radio frequency symbol stream, and then provides it to the antenna 452.

[0277] In the transmission from the first communication device 450 to the second communication device 410, the functions at the second communication device 410 are similar to the reception functions at the first communication device 450 described in the transmission from the second communication device 410 to the first communication device 450. Each receiver 418 receives a radio frequency signal through its corresponding antenna 420, converts the received radio frequency signal into a baseband signal, and provides the baseband signal to the multi-antenna reception processor 472 and the reception processor 470. The reception processor 470 and the multi-antenna reception processor 472 jointly implement the functions of the L1 layer. The controller / processor 475 implements the L2 layer functions. The controller / processor 475 can be associated with a memory 476 that stores program codes and data. The memory 476 can be referred to as a computer-readable medium. In the transmission from the first communication device 450 to the second communication device 410, the controller / processor 475 provides multiplexing between transport and logical channels, packet reassembly, decryption, packet header decompression, control signal processing to recover the upper layer data packets from the first communication device 450. The upper layer data packets from the controller / processor 475 may be provided to the core network or all protocol layers above the L2 layer, and various control signals may also be provided to the core network or L3 for L3 processing.

[0278] As an embodiment, the first communication device 450 apparatus includes: at least one processor and at least one memory, the at least one memory including computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor, and the first communication device 450 apparatus at least includes: receiving RRC signaling sent by a source cell, the RRC signaling including configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; as a response to the first execution condition being satisfied, performing LTM cell switching; initiating a process of sending an SR to the first candidate target cell, the process of initiating the sending of an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; wherein, the process of initiating the sending of an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, meaning that: only when the LTM cell switching performed is an LTM cell switching without RACH, the process of initiating an SR to the first candidate target cell is executed.

[0279] As an embodiment, the first communication device 450 apparatus includes: a memory storing a computer-readable instruction program, the computer-readable instruction program generates an action when executed by at least one processor, the action including: receiving RRC signaling sent by a source cell, the RRC signaling including configuration information of a first candidate target cell; the configuration information of the first candidate target cell including a first execution condition; performing LTM cell switching as a response to the first execution condition being satisfied; sending an SR to the first candidate target cell, the sending of the SR to the first candidate target cell depending on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; wherein, the sending of the SR to the first candidate target cell depending on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH means that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH.

[0280] As an embodiment, the second communication device 410 device includes: at least one processor and at least one memory, the at least one memory includes computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor. The second communication device 410 device at least: receives an SR, the SR depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH; the meaning of the SR depending on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH is: the SR is sent only when the LTM cell handover performed is an LTM cell handover without RACH; wherein the SR is triggered by the first execution condition being satisfied, the first execution condition is included in the configuration information of the first candidate target cell, and the configuration information of the first candidate target cell is included in the RRC signaling from the source cell to the sender of the SR.

[0281] As an embodiment, the second communication device 410 apparatus includes: a memory storing a computer-readable instruction program, the computer-readable instruction program generates an action when executed by at least one processor, the action including: receiving an SR, the SR depends on whether the LTM cell switch performed is an LTM cell switch based on RACH or an LTM cell switch without RACH; the SR depends on whether the LTM cell switch performed is an LTM cell switch based on RACH or an LTM cell switch without RACH, meaning that: the SR is sent only when the LTM cell switch performed is an LTM cell switch without RACH; wherein the SR is triggered by the first execution condition being satisfied, the first execution condition being included in the configuration information of the first candidate target cell, and the configuration information of the first candidate target cell being included in the RRC signaling from the source cell to the sender of the SR.

[0282] As an embodiment, the second communication device 410 device includes: at least one processor and at least one memory, the at least one memory including computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor. The second communication device 410 device at least: sends RRC signaling to the first node, the RRC signaling includes at least configuration information of the first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; wherein the first node performs LTM cell switching when the first execution condition is met; sends SR to the first candidate target cell, the sending of SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the sending of SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH.

[0283] As an embodiment, the second communication device 410 apparatus includes: a memory storing a computer-readable instruction program, wherein the computer-readable instruction program generates an action when executed by at least one processor, and the action includes: sending RRC signaling to the first node, the RRC signaling including configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; wherein the first node performs LTM cell switching when the first execution condition is met; sending SR to the first candidate target cell, wherein the sending of SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the meaning of sending SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH is that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH.

[0284] As an embodiment, the first communication device 450 corresponds to the first node in the present invention.

[0285] As an embodiment, the second communication device 410 corresponds to the second node in the present invention.

[0286] As an embodiment, the second communication device 410 corresponds to the third node in the present invention.

[0287] As an embodiment, the first communication device 450 is a UE.

[0288] As an embodiment, the first communication device 450 is a relay.

[0289] As an embodiment, the second communication device 410 is a base station device.

[0290] As an embodiment, the second communication device 410 is a distribution unit of a base station.

[0291] As an embodiment, the second communication device 410 is a piece of code in a distributed unit of a base station.

[0292] As an embodiment, at least one of the antenna 452, the transmitter 454, the multi-antenna transmit processor 457, the transmit processor 468 or the controller / processor 459 is used to send the uplink signal in the present invention.

[0293] As an embodiment, at least one of the antenna 420, the receiver 418, the multi-antenna receiving processor 472, the receiving processor 470 or the controller / processor 475 is used to receive the uplink signal in the present invention.

[0294] As an embodiment, at least one of the antenna 420, the transmitter 418, the multi-antenna transmit processor 471, the transmit processor 416 or the controller / processor 475 is used to send the first information in the present invention.

[0295] As an embodiment, at least one of the antenna 452, the receiver 454, the multi-antenna reception processor 458, the reception processor 456 or the controller / processor 459 is used to receive the first information in the present invention.

[0296] As an embodiment, at least one of the antenna 420, the transmitter 418, the multi-antenna transmit processor 471, the transmit processor 416 or the controller / processor 475 is used to send the RRC signaling in the present invention.

[0297] As an embodiment, at least one of the antenna 452, the receiver 454, the multi-antenna reception processor 458, the reception processor 456 or the controller / processor 459 is used to receive the RRC signaling in the present invention.

[0298] As an embodiment, at least one of the antenna 420, the transmitter 418, the multi-antenna transmit processor 471, the transmit processor 416 or the controller / processor 475 is used to send the SR signal in the present invention.

[0299] Example 5

[0300] Embodiment 5 illustrates a wireless signal transmission flow chart according to an embodiment of the present invention, as shown in the attached figure. Figure 5 It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present invention.

[0301] For the first node N51, in step S511, the RRC signaling is received, and the RRC signaling is an RRC message. The RRC signaling is sent by the source cell, that is, the third node N53. In one embodiment, the third node N53 is also a base station of the serving cell.

[0302] The first node N51 performs LTM cell switching in step S512, triggers SR in step S513, starts a timer in step S514, sends SR in step S515, and cancels the timer in step S516.

[0303] For the second node N52, the SR is received in step S521, and the LTM cell switching is completed in step S522.

[0304] For the third node N53, an RRC signaling is sent in step S531. The RRC signaling is sent to the first node N51.

[0305] Specifically, after receiving the RRC signaling, the first node N51 can store the RRC signaling. The RRC signaling includes configuration information of the first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition. After receiving the RRC signaling, the first node N51 can clarify whether RACH-based LTM cell switching can be performed, and whether RACH-free LTM switching can be performed. When performing LTM cell switching, which candidate target cells can be used for cell switching and the configuration information of each candidate target cell. In addition, the first node N51 can also learn the corresponding execution conditions for performing LTM cell switching from the configuration information of each candidate target cell.

[0306] After receiving the RRC signaling, the first node N51 may continue to monitor the source cell, for example, measure the reference signal of the source cell. The reference signal includes but is not limited to CSI-RS, SSB. In addition, the first node N51 may measure each candidate target cell based on the configuration information of each candidate target cell obtained by the RRC signaling, for example, measure the CSI-RS and / or SSB of each candidate target cell, so as to determine whether the first node N51 meets the first execution condition.

[0307] In one embodiment, the first execution condition includes a condition for satisfying LTM cell switching. In a specific implementation, the first execution condition may include: the signal strength or channel quality of the source cell is lower than or equal to a preset first threshold. Alternatively, the first execution condition may include: the signal strength or channel quality of the source cell is lower than or equal to a preset first threshold, and the signal strength or channel quality of the candidate target cell is higher than or equal to a preset second threshold.

[0308] When the first node N51 satisfies the first execution condition, in response to satisfying the first execution condition, the first node N51 may execute step S512 to perform LTM cell switching.

[0309] For example, the first node N51 may learn the first execution condition in the configuration information of the first candidate target cell. Based on this, if the first node N51 learns through measurement that it meets the first execution condition, it may perform LTM cell switching to the first candidate target cell.

[0310] As an embodiment, the LTM cell switching may be RACH-based LTM or RACH-free LTM.

[0311] In specific implementation, the first node N51 determines to perform RACH-based LTM on the first candidate target cell. At this time, a random access sequence can be sent to the first candidate target cell. It should be noted that the premise of using RACH-based LTM is that the RRC signaling includes random access resources used to configure the first candidate target cell.

[0312] As a variant implementation, the first node N51 determines to perform LTM without RACH to the first candidate target cell. At this time, SR can be sent to the first candidate target cell. It should be noted that the premise of using LTM without RACH is that the RRC signaling includes SR resources used to configure the first candidate target cell.

[0313] As an embodiment, step S513. triggering SR includes initiating a process of sending SR to the first candidate target cell.

[0314] As an embodiment, the sending of the SR to the first candidate target cell is performed after the LTM cell switching is started.

[0315] As an embodiment, the sending of the SR to the first candidate target cell is performed before the LTM cell switching is completed.

[0316] As an embodiment, the first node is not required to monitor the PDCCH of the first candidate target cell before the SR is sent.

[0317] As an embodiment, the first node is required to monitor the PDCCH of the first candidate target cell after the SR is sent.

[0318] As an embodiment, in response to receiving the PDCCH scheduling of the first candidate target cell, the process of sending the SR to the first candidate target cell is canceled.

[0319] Figure 5 In step S512, the first node N51 determines to perform LTM without RACH. Under this condition, step S513 can be performed to trigger SR. Accordingly, the first node N51 can select a first candidate SR configuration of the SR, and the first candidate SR configuration is associated with at least one SR resource.

[0320] As an embodiment, when the first node N51 executes LTM without RACH or before executing LTM without RACH, it is necessary to complete uplink synchronization of the first candidate target cell.

[0321] As an embodiment, sending the SR to the first candidate target cell depends on synchronization with the first candidate target cell, which means that the first node N51 needs to obtain a timing advance for the first candidate target cell before sending the SR.

[0322] As an embodiment, the first node N51 has obtained the timing advance for the first candidate target cell before initiating the process of sending the SR to the first candidate target cell.

[0323] As an embodiment, how to obtain the timing advance for the first candidate target cell is a prior art in the art.

[0324] In specific implementation, after uplink synchronization, the first node N51 receives a PDCCH scheduling of one of the candidate target cells. In response to receiving the PDCCH scheduling of any candidate target cell, the triggering of the SR to the first candidate target cell is canceled, and the sending of the SR is canceled.

[0325] As an embodiment, the meaning of canceling the process of sending SR to the first candidate target cell accompanying the expiration of the timer is: the expiration of the timer triggers the cancellation of the process of sending SR to the first candidate target cell.

[0326] As an embodiment, after the SR is sent, the process of sending the SR to the first candidate target cell is completed.

[0327] When executing step S513, step S514 may be executed simultaneously to start a timer. The timer is used to record whether the triggered SR is sent before the timer expires. If the first node N51 executes step S515 to send the SR before the timer expires, step S516 may be executed to cancel the timer or stop the timer.

[0328] As an embodiment, the SR is sent at the physical layer.

[0329] As a sub-embodiment of this embodiment, the SR is considered as a high-priority SR transmission.

[0330] As a sub-embodiment of this embodiment, the MAC entity considers that the SR is a SR to be transmitted with priority.

[0331] As an embodiment, the SR is a physical layer signal.

[0332] As an embodiment, the SR is transmitted on PUCCH.

[0333] As an embodiment, the first candidate SR is configured with a valid PUCCH resource. The SR is sent on a valid PUCCH resource. The valid PUCCH resource is a valid PUCCH resource for SR.

[0334] Afterwards, the node N52 executes step S521 to receive the SR, and executes step S522 to complete the LTM cell switching.

[0335] In one variation, receiving the SR means that the LTM cell switching is completed. In another variation, completing the LTM cell switching is performed first, and receiving and processing the SR is performed later.

[0336] As an embodiment, the present invention does not limit the order of step S513 and step S514.

[0337] As an embodiment, step S516 is performed before step S515, or step S516 and step S515 are performed in parallel.

[0338] As an embodiment, step S514 belongs to step S513 and is executed in parallel.

[0339] As an embodiment, the first node N51 is a user equipment.

[0340] As an embodiment, the first node N51 is a relay device.

[0341] As an embodiment, the second node N52 is a maintenance node of the first candidate target cell.

[0342] As an embodiment, the second node N52 is one of a TRP, a DU, a CU, or a base station device.

[0343] As an embodiment, the third node N53 is a maintenance node of the source cell or the serving cell.

[0344] As an embodiment, the third node N53 is a TRP, DU, CU, radio frequency unit or base station device.

[0345] As an embodiment, there is an ideal backhaul or a non-ideal backhaul between the second node N52 and the third node N53.

[0346] As an embodiment, the second node N52 and the third node N53 belong to different CUs or different DUs or different TRPs.

[0347] For the specific description of each wireless signal in this embodiment, reference can also be made to the relevant description in Embodiment 1.

[0348] Example 6

[0349] Embodiment 6 illustrates a wireless signal transmission flow chart according to another embodiment of the present invention, as shown in the attached figure. Figure 6 It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present invention.

[0350] Attached Figure 6 It is a feasibility flow chart of the first node N51 after executing step S514 to start the timer.

[0351] Specifically, after starting the timer, the first node N51 executes step S601 to determine whether the timer has expired. If not, step S602A is executed to determine whether the SR is successfully sent. If yes, it means that the SR is successfully sent, and then the process goes to step S516 in embodiment 5. If no, it means that the SR fails to be sent or is not successfully sent, and then the process goes to step S601 to continue monitoring the timer.

[0352] In specific implementation, if the timer expires, the process turns to step S602B after step S601, that is, the process of sending the SR to the first candidate target cell is canceled, and the execution of RACH-based LTM is rolled back.

[0353] As an embodiment, the fallback execution of RACH-based LTM only includes CBRA-based LTM.

[0354] As an embodiment, the fallback execution of RACH-based LTM includes CBRA-based LTM and CFRA-based LTM.

[0355] In a specific implementation, the first node N51 may use the C-RNTI identifier in the first candidate target cell to send the SR.

[0356] As an embodiment, when the SR is not successfully sent, the SR is pending.

[0357] As an embodiment, the SR being pending means that the SR is considered pending.

[0358] As an embodiment, the SR being pending means that the SR is a pending SR.

[0359] As an embodiment, the pending SR means that the SR process corresponding to the SR is in progress.

[0360] As an embodiment, the SR pending means that the SR is pending.

[0361] As an embodiment, the SR pending means that the SR is to be sent.

[0362] As an embodiment, the SR pending means that the SR is to be processed.

[0363] As an embodiment, the cancelling refers to cancel.

[0364] As an embodiment, the cancellation means no longer processing.

[0365] As an embodiment, the cancellation means that it is no longer to be sent.

[0366] As an embodiment, the canceling of sending the SR to the first candidate target cell includes: canceling the SR process corresponding to the SR.

[0367] As an embodiment, the canceling sending the SR to the first candidate target cell includes: canceling the pending state of the SR.

[0368] As an embodiment, the canceling of sending the SR to the first candidate target cell includes: the SR is no longer considered pending.

[0369] As an embodiment, the C-RNTI of the first node N51 in the first candidate target cell is the C-RNTI of the first node N51 in the source cell.

[0370] As an embodiment, a field in the RRC signaling indicates the C-RNTI of the first node N51 in the first candidate target cell.

[0371] As an embodiment, the C-RNTI of the first node N51 in the first candidate target cell is the C-RNTI of the first node in the cell group to which the first candidate target cell belongs.

[0372] As an embodiment, the RRC signaling includes a field, which is used to configure the timer.

[0373] During specific implementation, the timer is T304.

[0374] During specific implementation, the timer may be a timer of a MAC sublayer.

[0375] As an embodiment, the MAC sublayer of the first node N51 may indicate the expiration of the timer to an upper layer of the first node N51.

[0376] Figure 6 The scheme shown is a possible transmission scheme that occurs during the execution of Example 5. Figure 6 For more information on the working principle and working method of the first node N51 in the application scenario shown in FIG. Figure 5 The relevant description in will not be repeated here.

[0377] Example 7

[0378] Embodiment 7 illustrates a wireless signal transmission flow chart according to another embodiment of the present invention, as shown in the attached figure. Figure 7 shown.

[0379] Attached Figure 7 This is another feasible flow chart executed by the first node N51 after executing step S514 to start the timer.

[0380] Specifically, after starting the timer, the first node N51 executes step S701 to determine whether the timer has expired. If not, step S702A is executed to determine whether the SR is successfully sent. If yes, it means that the SR is successfully sent, and then step S70A can be executed, including canceling the timer, that is, executing step S516 shown in embodiment 5, and resetting the counter. If not, step S703B is turned to reset the timer.

[0381] In specific implementation, if the timer expires, the process turns to step S702B after step S701, that is, updating the counter, for example, adding 1 to the counter. Then, step S704 is executed to determine whether the counter has reached a maximum value. If the maximum value has been reached, step S705 is executed to cancel the process of sending the SR to the first candidate target cell and fall back to perform the RACH-based LTM. If the maximum value has not been reached, step S702A is turned to determine whether the SR has been successfully sent, and then step S703A or step S703B is executed according to the determination result.

[0382] Figure 7 The scheme shown is another possible transmission scheme that occurs during the execution of Example 5. Figure 7 For more information on the working principle and working method of the first node N51 in the application scenario shown in FIG. Figures 1 to 6 The relevant description in will not be repeated here.

[0383] As described above, through the technical solution provided by the embodiment of the present invention, the first node can send the SR to perform LTM cell switching without RACH, which makes it possible to ensure the robustness of conditional LTM.

[0384] Example 8

[0385] Embodiment 8 illustrates a wireless signal transmission flow chart according to another embodiment of the present invention, as shown in the attached figure. Figure 8 It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present invention.

[0386] Attached Figure 8 An example of a cell switching method suitable for application at a second node is provided. The second node may be a maintenance node of the first candidate target cell, and may be a network device of the first candidate target cell, such as a base station device.

[0387] Specifically, the cell switching method may include:

[0388] Step S801, receiving an SR sent to the first candidate target cell;

[0389] Among them, the SR received and sent to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the meaning of the SR received and sent to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH is: only when the LTM cell switching performed is an LTM cell switching without RACH, the SR is issued to the first candidate target cell.

[0390] The first node performing LTM cell switching is a response to satisfying a first execution condition, the first execution condition is included in the configuration information of the first candidate target cell, and the configuration information of the first candidate target cell is included in the RRC signaling sent by the source cell to the first node.

[0391] In a specific implementation, the LTM cell switching can be RACH-based LTM or RACH-free LTM depending on the RRC signaling. For RACH-based LTM, the RRC signaling may at least include relevant configuration information suitable for initiating a random access procedure in the first candidate target cell. For RACH-free LTM, the RRC signaling may at least include execution conditions and / or configuration information that can be satisfied for initiating RACH-free LTM.

[0392] In a specific implementation, step S801 is an execution step after the first node successfully sends an SR. The first node may include the configuration information of the first candidate target cell in the RRC signaling sent by its source cell. The configuration information of the first candidate target cell includes the first execution condition. When the first node meets the first execution condition and determines to perform LTM cell switching without RACH, the first node may send an SR to the first candidate target cell.

[0393] In a specific implementation, the configuration information of the first candidate target cell may include at least one candidate SR configuration, and each candidate SR configuration is associated with at least one SR resource; the receiving of the SR sent to the first candidate target cell includes: receiving the SR sent to the first candidate target cell on one SR resource among the at least one SR resource.

[0394] For the first candidate target cell, whether there is a chance to receive the SR is unknown. The uplink resource of the SR sent by the first node may be a PUCCH resource or a PUSCH resource. Preferably, the uplink resource is a PUCCH resource. The PUCCH resource may come from the candidate SR configuration sent by the source cell. The candidate SR configuration is included in the configuration information of the first candidate target cell.

[0395] As an embodiment, the configuration information of the first candidate target cell may be determined through negotiation between the source cell and each candidate target cell.

[0396] After receiving the SR, the first candidate target cell may learn that the first node is about to or has completed the LTM cell handover without RACH. Afterwards, the first candidate target cell becomes the new serving cell of the first node. Further, the new serving cell may send a signaling to the first node to delete the context information of the previous source cell. Accordingly, after receiving the signaling, the first node may complete the context information of the previous source cell.

[0397] During specific implementation, the signaling may be an RRC reconfiguration message or a MAC CE.

[0398] Those skilled in the art will appreciate that step S801 can be regarded as the same as the above Figure 1 , Figures 5 to 7 The steps in the embodiment shown correspond to the execution steps, and the two complement each other in terms of specific implementation principles and logic. Figure 1 , Figures 5 to 7 The relevant description of the illustrated embodiment will not be repeated here.

[0399] Example 9

[0400] Embodiment 9 illustrates another wireless signal transmission flow chart according to an embodiment of the present invention, as shown in the attached figure. Fig. 9 It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present invention.

[0401] Attached Fig. 9 An example of a cell switching method suitable for application in a third node is provided. The third node may be a maintenance node of a source cell of the first node, and may be a network device of the source cell, such as a base station device.

[0402] Specifically, the method in the third node applicable to cell switching may include:

[0403] Step S901: Send RRC signaling to the first node.

[0404] The RRC signaling includes at least configuration information of a first candidate target cell; and the configuration information of the first candidate target cell includes a first execution condition.

[0405] Among them, the first node executes LTM cell switching when the first execution condition is met; sends SR to the first candidate target cell, and the sending of SR to the first candidate target cell depends on whether the LTM cell switching executed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the sending of SR to the first candidate target cell depends on whether the LTM cell switching executed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the SR is sent only when the LTM cell switching executed is an LTM cell switching without RACH.

[0406] In specific implementation, in step S901, the source cell may send RRC signaling to the first node. The RRC signaling may be an RRC message. The RRC message may include configuration information of one or more candidate target cells, including the configuration information of the first candidate target cell.

[0407] As an embodiment, the configuration information of the first candidate target cell may include at least one candidate SR configuration, and each of the candidate SR configurations is associated with at least one SR resource. The SR resource is used to send the SR.

[0408] In a specific implementation, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling. When the RRC signaling includes configuration information for RACH-based LTM, the first node can choose to use RACH-based LTM to perform cell switching. When the RRC signaling includes configuration information for RACH-free LTM, the first node can choose to use RACH-free LTM to perform cell switching.

[0409] Those skilled in the art will appreciate that step S901 can be regarded as the same as the above Figure 1 , Figures 5 to 8 The steps in the embodiment shown correspond to the execution steps, and the two complement each other in terms of specific implementation principles and logic. Figure 1 , Figures 5 to 8 The relevant description of the illustrated embodiment will not be repeated here.

[0410] Example 10

[0411] Embodiment 10 illustrates a structural block diagram of a processing device used in a first node according to an embodiment of the present invention; Fig.10 As shown. Fig.10 In the embodiment, the processing device 1000 in the first node includes a receiver 1001, a processor 1002 and a transmitter 1003.

[0412] In one embodiment, a receiver 1001 receives RRC signaling sent by a source cell, where the RRC signaling includes configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition;

[0413] The processor 1002 executes LTM cell switching in response to the first execution condition being satisfied;

[0414] The transmitter 1003 initiates a process of sending a SR (scheduling request) to the first candidate target cell, wherein the process of initiating the sending of the SR to the first candidate target cell depends on whether the LTM cell handover performed is a RACH-based LTM cell handover or a RACH-free LTM cell handover;

[0415] The process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the process of initiating an SR to the first candidate target cell is executed only when the LTM cell switching performed is an LTM cell switching without RACH.

[0416] As an embodiment, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0417] As an embodiment, the process of initiating sending an SR to the first candidate target cell includes attempting to send an SR.

[0418] As an embodiment, the sending of the SR is independent of whether there is data to be transmitted.

[0419] As an embodiment, the sending of the SR is independent of whether there is a MAC CE to be transmitted.

[0420] As an embodiment, the sending of the SR does not depend on whether there is data to be transmitted.

[0421] As an embodiment, the sending of the SR does not depend on whether there is a MAC CE to be transmitted.

[0422] As an embodiment, the SR is not associated with any data.

[0423] As an embodiment, the SR is not associated with any MAC CE.

[0424] As an embodiment, the process of initiating sending an SR to the first candidate target cell is performed after the execution of the LTM cell handover starts.

[0425] As an embodiment, the process of initiating sending an SR to the first candidate target cell is performed before the execution of the LTM cell handover is completed.

[0426] As an embodiment, the first node is not required to monitor the PDCCH of the first candidate target cell before the SR is sent.

[0427] As an embodiment, the benefits of the above method include: saving PDCCH resources, saving power, and reducing interference to other nodes.

[0428] As an embodiment, in response to receiving the PDCCH scheduling of the first candidate target cell, the process of sending the SR to the first candidate target cell is canceled.

[0429] As an embodiment, in response to receiving PDCCH scheduling of any of the first candidate target cells, the process of sending the SR to the first candidate target cell is canceled.

[0430] As an embodiment, the SR is the first SR sent to the first candidate target cell.

[0431] As an embodiment, the SR is the first signal sent to the first candidate target cell.

[0432] During specific implementation, the transmitter 1003 may trigger the SR based on the physical layer synchronization of the first candidate target cell, and send the SR to the first candidate target cell.

[0433] In a specific implementation, the transmitter 1003 may start a timer when the SR is triggered; when the timer expires, the process of sending the SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back.

[0434] As an embodiment, the fallback execution of RACH-based LTM only includes CBRA-based LTM.

[0435] As an embodiment, the benefits of the above method include: using CBRA is more reliable and is not limited by resources and initiation time.

[0436] As an embodiment, the fallback execution of RACH-based LTM includes CBRA-based LTM and CFRA-based LTM.

[0437] As an embodiment, the benefits of the above method include: the benefits of using CBRA and CFRA include: improving the probability of successful random access.

[0438] In a specific implementation, the transmitter 1003 may be used to cancel the timer after sending an SR to the first candidate target cell during the operation of the timer; wherein the SR is the first uplink signal sent by the first node to the first candidate target cell.

[0439] In a specific implementation, the transmitter 1003 may update a counter when the SR fails to be sent; when the counter reaches a preset value, the counter is reset, and the process of sending the SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back; wherein the counter is used to record the number of SR sending failures.

[0440] In a specific implementation, the configuration information of the first candidate target cell includes at least one candidate SR configuration, and each candidate SR configuration is associated with at least one SR resource; the transmitter 1003 can be used to send an SR to the first candidate target cell through one SR resource among the at least one SR resource.

[0441] In a specific implementation, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0442] As an embodiment, the receiver 1001 includes the attached Figure 4 Antenna 452, receiver 454, multi-antenna reception processor 458, reception processor 456, controller / processor 459, memory 460 and data source 467.

[0443] As an embodiment, the receiver 1001 includes the attached Figure 4 Antenna 452, receiver 454, multi-antenna receive processor 458, and receive processor 456.

[0444] As an embodiment, the receiver 1001 includes the attached Figure 4 Antenna 452, receiver 454, and receive processor 456.

[0445] As an embodiment, the transmitter 1003 may include the attached Figure 4 Antenna 452, transmitter 454, multi-antenna transmit processor 457, transmit processor 468, controller / processor 459, memory 460 and data source 467.

[0446] As an embodiment, the transmitter 1003 may include the attached Figure 4 Antenna 452, transmitter 454, multi-antenna transmit processor 457, and transmit processor 468.

[0447] As an embodiment, the transmitter 1003 may include the attached Figure 4 Antenna 452, transmitter 454, and transmit processor 468.

[0448] For more information about the working principle and working method of the processing device 1000 in the first node, please refer to the above Figures 1 to 7 The relevant description of the technical solution is shown in the figure and will not be repeated here.

[0449] Embodiment 11

[0450] Embodiment 11 illustrates a structural block diagram of a processing device used in a second node according to an embodiment of the present invention; Fig.11 As shown in the attached Fig.11 In the embodiment, the processing device 1100 in the second node includes a receiver 1101. The processing device 1100 in the second node may be executed by a network side, such as a base station device.

[0451] As an embodiment, the receiver 1101 receives an SR, wherein the SR depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the SR depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, meaning that the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH; wherein the SR is triggered by the first execution condition being satisfied, the first execution condition being included in the configuration information of the first candidate target cell, and the configuration information of the first candidate target cell being included in the RRC signaling from the source cell to the sender of the SR.

[0452] In a specific implementation, the configuration information of the first candidate target cell includes at least one candidate SR configuration, and each of the candidate SR configuration is associated with at least one SR resource.

[0453] As an embodiment, the receiver 1001 receives the SR sent to the first candidate target cell on one SR resource among the at least one SR resource.

[0454] In a specific implementation, whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

[0455] As an embodiment, the receiver 1101 includes the attached Figure 4 Antenna 420, receiver 418, multi-antenna reception processor 472, reception processor 470, controller / processor 475, and memory 476.

[0456] As an embodiment, the receiver 1101 includes the attached Figure 4 Antenna 420, receiver 418, multi-antenna receive processor 472, receive processor 470.

[0457] As an embodiment, the receiver 1101 includes the attached Figure 4 Antenna 420, receiver 418, and receive processor 470.

[0458] For more information about the working principle and working method of the processing device 1100 in the second node, please refer to the above Figures 1 to 7 The relevant description of the technical solution is shown in the figure and will not be repeated here.

[0459] Example 12

[0460] Embodiment 12 illustrates a structural block diagram of a processing device used in a third node according to an embodiment of the present invention; Fig.12 As shown in the attached Fig.12 In the embodiment, the processing device 1200 in the third node includes a transmitter 1201. The processing device 1200 in the third node may be executed by a network side, such as a base station device.

[0461] In specific implementation, the transmitter 1201 is used to send RRC signaling to the first node, and the RRC signaling includes configuration information of at least a first candidate target cell; the configuration information of the first candidate target cell includes a first execution condition; wherein, when the first execution condition is met, the first node performs LTM cell switching; an SR is sent to the first candidate target cell, and the sending of the SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH; the sending of the SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, meaning that: the SR is sent only when the LTM cell switching performed is an LTM cell switching without RACH.

[0462] As an embodiment, the transmitter 1201 includes the attached Figure 4 Antenna 420, transmitter 418, multi-antenna transmit processor 471, transmit processor 416, controller / processor 475, and memory 476.

[0463] As an embodiment, the transmitter 1201 includes the attached Figure 4 Antenna 420, transmitter 418, multi-antenna transmit processor 471, and transmit processor 416.

[0464] As an embodiment, the transmitter 1201 includes the attached Figure 4 Antenna 420, transmitter 418, and transmit processor 416.

[0465] For more information about the working principle and working method of the processing device 1200 in the third node, please refer to the above Figures 1 to 7 The relevant description of the technical solution is shown in the figure and will not be repeated here.

[0466] A person of ordinary skill in the art can understand that all or part of the steps in the above method can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a hard disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module unit in the above embodiment can be implemented in the form of hardware or in the form of a software function module, and the present invention is not limited to any specific form of software and hardware combination. The user equipment, terminal and UE in the present invention include but are not limited to drones, communication modules on drones, remote-controlled aircraft, aircraft, small aircraft, mobile phones, tablet computers, notebooks, vehicle-mounted communication equipment, wireless sensors, Internet cards, Internet of Things terminals, RFID terminals, NB-IOT terminals, MTC (Machine Type Communication) terminals, eMTC (enhancedMTC) terminals, data cards, Internet cards, vehicle-mounted communication equipment, low-cost mobile phones, low-cost tablet computers and other wireless communication devices. The base stations or system equipment in the present invention include but are not limited to macrocell base stations, microcell base stations, home base stations, relay base stations, gNB (NR Node B) NR Node B, TRP (Transmitter Receiver Point, sending and receiving node) and other wireless communication equipment.

[0467] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A first node for controlling SR transmission in LTM cell switching, characterized in that: include: A receiver receives an RRC signaling sent by a source cell, wherein the RRC signaling includes configuration information of at least a first candidate target cell; The configuration information of the first candidate target cell includes a first execution condition; A processor, in response to the first execution condition being satisfied, performs LTM cell switching; A transmitter, initiating a process of sending an SR (scheduling request) to the first candidate target cell, wherein the process of initiating sending the SR to the first candidate target cell depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH; The process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the process of initiating an SR to the first candidate target cell is executed only when the LTM cell switching performed is an LTM cell switching without RACH.

2. The first node according to claim 1, characterized in that Sending the SR to the first candidate target cell depends on synchronization with the first candidate target cell.

3. The first node according to claim 1 or 2, characterized in that: include: The transmitter, along with initiating the process of sending the SR to the first candidate target cell, starts a timer; With the expiration of the timer, the process of sending the SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back.

4. The first node according to claim 3, characterized in that include: The transmitter, during the operation of the timer, stops the timer after sending the SR to the first candidate target cell; The SR is the first uplink signal sent by the first node to the first candidate target cell.

5. The first node according to claim 1 or 2, characterized in that: include: The transmitter, in response to failure to send the SR to the first candidate target cell, updates a counter; When the counter reaches a preset value, the counter is reset, the process of sending the SR to the first candidate target cell is canceled, and the RACH-based LTM is rolled back; The counter is used to record the number of SR sending failures.

6. The first node according to any one of claims 1 to 5, characterized in that: include: The transmitter sends an SR to the first candidate target cell on one SR resource of at least one SR resource; The configuration information of the first candidate target cell includes the at least one candidate SR configuration, and each of the candidate SR configurations is associated with at least one SR resource.

7. The first node according to claim 6, characterized in that include: The receiver receives an RRC reconfiguration message of the first candidate target cell, where the RRC reconfiguration message includes deleting the context information of the source cell and retaining the configuration information of at least the first candidate target cell.

8. The first node according to any one of claims 1 to 7, characterized in that: Whether the LTM cell switching is RACH-based LTM or RACH-free LTM depends on the RRC signaling.

9. The first node according to any one of claims 1 to 8, characterized in that: The first execution condition includes: the quality of the first candidate target cell is better than a given threshold; and the configuration information of the first candidate target cell includes the given threshold.

10. A method in a first node for controlling SR transmission in LTM cell switching, characterized in that: include: receiving an RRC signaling sent by a source cell, wherein the RRC signaling includes configuration information of at least a first candidate target cell; The configuration information of the first candidate target cell includes a first execution condition; In response to the first execution condition being satisfied, performing LTM cell switching; Initiate a process of sending an SR to the first candidate target cell, wherein the process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell handover performed is an LTM cell handover based on RACH or an LTM cell handover without RACH; The process of initiating sending an SR to the first candidate target cell depends on whether the LTM cell switching performed is an LTM cell switching based on RACH or an LTM cell switching without RACH, which means that the process of initiating an SR to the first candidate target cell is executed only when the LTM cell switching performed is an LTM cell switching without RACH.

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