Cell switching method and device

Abstract

Disclosed are a cell switching method and device, the method comprising: receiving first information, the first information being sent as a response satisfying a first execution condition when a first node monitors a first cell and candidate target cells in a candidate target cell set, the first execution condition comprises that the signal intensity of a first cell received by the first node is not higher than a first threshold value; at least one candidate target cell in the candidate target cell set is notified, so that the first node responds to the condition that a second execution condition is met, and is switched to one of the candidate target cells; wherein the switching of the first node to one of the candidate target cells depends on the transmission of the first information; the switching is the LTM of a non-RACH (Random Access Channel); the candidate target cell set is configured in advance. According to the method and the device, the condition-based RACH-free LTM cell switching can be better supported, and resource waste is avoided.

Description

Technical Field

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

[0002] The application scenarios of future wireless communication systems are becoming more and more diversified, and different application scenarios have different performance requirements for the system. In order to meet the different performance requirements of various application scenarios, the 3GPP (3rd Generation Partner Project) Radio Access Network (RAN) #72 plenary meeting decided to study the new radio technology (New Radio, NR) (or 5G), and the NR work item (Work Item, WI) agenda was passed at the 3GPP RAN #75 plenary meeting, starting the standardization work on NR.

[0003] In the new air interface technology, cell switching is one of the most basic requirements. The basic requirement of cell switching is to reduce the switching delay and reduce the impact on delay-sensitive services. In order to adapt to various application scenarios and meet different needs, 3GPP has been evolving the cell switching technology. When the user equipment (UE) changes cells, it may involve handover, conditional handover (CHO), layer 1 / 2 triggered mobility (LTM, layer 1 / layer 2 triggered mobility, L1 / L2 triggered mobility), cell switch, primary and secondary cell change (Conditional PScell ​​Change, CPC), etc. Summary of the invention

[0004] Although 3GPP introduced CPC, CHO and other technologies in Release 17 (Rel-17), these technologies are still based on Layer 3 (L3), which has the characteristics of long delay, large signaling overhead and long interruption time. Therefore, at the 3GPP RAN#94e plenary meeting, it was decided to start WI standardization work on LTM mobility enhancement technology based on L1 / L2 (Layer 1 / Layer 2) to improve cell handover.

[0005] In response to the demand for enhanced mobility based on L1 / L2 in the NR system, the present invention discloses a solution. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be arbitrarily combined with each other. 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. Further, although the original intention of the present invention is for the terminal and base station scenario, the present invention is also applicable to other scenarios facing similar problems, such as vehicle-to-everything (V2X), communication scenarios between the terminal and the relay, and the relay and the base station, to achieve similar technical effects in the terminal and base station scenarios. In addition, the use of a unified solution for different scenarios (including but not limited to V2X scenarios and communication scenarios between the terminal and the base station) also helps to reduce hardware complexity and cost. In particular, the interpretation of the terms (Terminology), nouns, functions, and variables in the present invention (if not otherwise specified) can refer to the definitions in the 3GPP specification protocols TS38 series and TS37 series.

[0006] To solve the above technical problems, an embodiment of the present invention provides a method in a first node for cell switching, comprising: monitoring a first cell and candidate target cells in a set of candidate target cells, and sending first information as a response to satisfying a first execution condition, wherein the first execution condition comprises: a signal strength of the first cell is not higher than a first threshold; as a response to satisfying a second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is an LTM cell switch (cell switch) without a random access channel (Random Access Channel-less, RACH-less); and the set of candidate target cells is pre-configured.

[0007] In an embodiment of the present invention, under the premise of pre-configured candidate target cell set, the first node (such as UE) can monitor the source cell (service cell, such as the first cell) and the candidate target cell, determine whether the signal strength of the service cell of the first node is higher than the first threshold, and then determine whether the first execution condition is met, and send the first information when the first execution condition is met. After sending the first information and when the second execution condition is met, the first node can conditionally switch to one of the candidate target cells in LTM without RACH. This method can realize L1 / L2 cell switching under L3 triggered by the first node, reasonably execute the conditional LTM (conditional LTM) cell switching process, improve the robustness of LTM switching by meeting multiple execution conditions, and the UE autonomously executes the switching, which is conducive to realizing the rapid exchange of service cells.

[0008] As an embodiment, the above method sends the first information only when the first execution condition is met and the LTM switch to the candidate target cell is performed only when the second condition is further met, without sending a random access sequence or performing a random access process. This can effectively avoid ping-pong switching and send switching commands through protocol layers below layer 3, greatly reducing switching delay, avoiding waste of resources, and supporting non-RACH LTM cell switching.

[0009] As an embodiment, a problem to be solved by the present invention is: how to support high robustness of cell switching triggered by UE based on conditions and reduce or avoid resource waste during conditional RACH-free LTM cell switching. The technical solution provided by the present invention solves the above technical problem well.

[0010] As an embodiment, the above method initiates conditional LTM cell switching without RACH by the first node after the first execution condition is met, rather than being initiated autonomously by the serving cell of the first node, which can further adapt to the UE communication process and speed up the cell switching process.

[0011] As an embodiment, the above method can effectively support the demand for rapid cell switching caused by rapid channel changes and reduce service interruption time.

[0012] As an embodiment, the present invention is particularly applicable to a mobility enhancement scenario.

[0013] As an embodiment, the first cell is a service cell or a source cell, and is a service cell of the first node.

[0014] According to one aspect of the present invention, the second execution condition includes: the signal strength of the received first cell is not higher than a second threshold; or, the second execution condition includes: the signal strength of at least one candidate target cell is not lower than a third threshold.

[0015] As an embodiment, the signal strength of the first cell may be the channel quality of the first cell, or may be a reference signal resource of the first cell, a signal strength of a beam, etc.

[0016] As an embodiment, the monitoring of the first cell may be measurement of the first cell, which is layer 3 (layer 3, L3) measurement.

[0017] As an embodiment, the first threshold is a cell-level measurement result, and the second threshold is a beam-level measurement result.

[0018] In one implementation, the first threshold may be a threshold of L3, and the second threshold may be a threshold of L1. In another implementation, the first threshold is for multiple reference signal resources, and the second threshold is for one reference signal resource.

[0019] As an embodiment, the first information indicates that the signal strength of the first cell is not higher than the first threshold. In an exemplary example, the first threshold may be pre-configured by the network or set by default.

[0020] In one embodiment, when the first node sends the first information, it is implicitly indicated that the first node meets the conditions for performing LTM without RACH conditions. In another embodiment, when the first node sends the first information, it is implicitly indicated that the first node preliminarily meets the conditions for performing LTM without RACH conditions, and it is very likely that it can switch to one of the candidate target cells after a short time delay. In another embodiment, in addition to indicating that the signal strength of the received first cell is not higher than the first threshold, the first information also indicates that LTM switching will be performed within a preset time period. For example, the first information uses bit information to indicate that LTM switching will be performed within a preset time period if no other information is reported. The preset time period can be pre-configured or defaulted.

[0021] As an embodiment, the detection of at least one candidate target cell in the candidate target cell set depends on the sending of the first information. In other words, if the first information is not sent, the first node does not need to detect at least one candidate target cell in the candidate target cell set. The detection refers to blind detection of PDCCH (physical downlink control channel) or blind decoding of DCI (downlink control information).

[0022] As an embodiment, in response to satisfying the second execution condition, switching to one of the candidate target cells depends on the sending of the first information.

[0023] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information includes: if the first information is not sent, the at least one candidate target cell will not be switched to one of the candidate target cells if the second execution condition is met.

[0024] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information includes: the first information is not sent, and the switching to one of the candidate target cells will not be performed even if the first cell satisfies the second execution condition.

[0025] As an embodiment, the switching to one of the candidate target cells depends on the sending of the first information, including: if the first information is not sent, even if the first cell satisfies the second execution condition and at least one of the candidate target cells satisfies the second execution condition, switching to one of the candidate target cells will not occur.

[0026] According to one aspect of the present invention, the method includes: the first information carries at least one candidate target cell in the candidate target cell set.

[0027] The first node carries one or more candidate target cells in the first information, so that the serving cell can clearly know the candidate target cells selected by the first node for switching based on the first information, which is beneficial to reducing the information interaction cost between network devices.

[0028] Preferably, the first information carries only one candidate target cell. This technical solution can save power consumption and signaling.

[0029] According to one aspect of the present invention, the method comprises: starting a timer when sending the first information, and detecting a switched cell when the timer expires.

[0030] This solution detects the switched cell only after the timer has run for a period of time, which is beneficial to reducing unnecessary power consumption, thereby saving network resources and improving resource utilization.

[0031] According to one aspect of the present invention, the method includes: receiving resource configuration information sent by the switched cell, and sending an uplink signal on the switched cell based on the resource configuration information.

[0032] This method can quickly implement the sending of uplink signals on the cell after switching, thereby completing data interaction.

[0033] According to one aspect of the present invention, the received signal strength of the first cell is at least one of the following: a measurement result of a reference signal; a signal strength of other signals except the reference signal; a signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0034] The method monitors the signal strength to determine the signal quality of the serving cell, which is conducive to quickly implementing a reasonable switching strategy.

[0035] According to one aspect of the present invention, the candidate target cell set is pre-configured through RRC signaling; the configuration information of the candidate target cell includes one or more of the following:

[0036] The cell identifier of the candidate target cell;

[0037] The cell offset of the candidate target cell;

[0038] The transmit power of the candidate target cell.

[0039] This method enables the terminal device (such as the first node) to know the information of the candidate target cell in advance, which is conducive to the subsequent selection of a suitable switching solution.

[0040] According to one aspect of the present invention, the method includes: obtaining a timing advance of a target cell after switching depending on whether the first execution condition is satisfied.

[0041] The method depends on whether the first execution condition is met, and then determines whether to obtain the timing advance, thereby avoiding unnecessary resource consumption.

[0042] To solve the above technical problems, an embodiment of the present invention also provides a method in a second node for cell switching, comprising: receiving first information, wherein the first information is monitored by the first node and a candidate target cell in a candidate target cell set, and is sent as a response to satisfying a first execution condition, wherein the first execution condition comprises: the signal strength of the first cell received by the first node is not higher than a first threshold; notifying at least one candidate target cell in the candidate target cell set so that the first node switches to one of the candidate target cells in response to satisfying the second execution condition; wherein the first node switches to one of the candidate target cells depending on the sending of the first information; the switching is LTM without RACH; and the candidate target cell set is pre-configured.

[0043] According to one aspect of the present invention, the first information carries at least one candidate target cell in the candidate target cell set.

[0044] According to one aspect of the present invention, the received signal strength of the first cell is at least one of the following:

[0045] Measurement results of reference signals;

[0046] signal strengths of other signals except the reference signal;

[0047] The signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0048] According to one aspect of the present invention, the candidate target cell set is pre-configured through RRC signaling; the configuration information of the candidate target cell includes one or more of the following:

[0049] The cell identifier of the candidate target cell;

[0050] The cell offset of the candidate target cell;

[0051] The transmit power of the candidate target cell.

[0052] As an embodiment, the above method can simplify UE implementation.

[0053] As an embodiment, the above method is applicable to a scenario in which the second node is a base station of the first cell.

[0054] To solve the above technical problems, an embodiment of the present invention also provides a method in a third node for cell switching, comprising: receiving notification information sent from a second node, the notification information including at least one candidate target cell in a candidate target cell set, the candidate target cell set being pre-configured by the second node to the first node, so that the first node monitors the first cell and each candidate target cell in the candidate target cell set, and sends first information to the second node in response to satisfying a first execution condition; wherein the first execution condition comprises: the signal strength of the received first cell is not higher than a first threshold; the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH.

[0055] According to one aspect of the present invention, the first information carries at least one candidate target cell in the candidate target cell set.

[0056] According to one aspect of the present invention, the received signal strength of the first cell is at least one of the following: a measurement result of a reference signal; a signal strength of other signals except the reference signal; a signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0057] According to one aspect of the present invention, the candidate target cell set is pre-configured by the second node through RRC signaling; the configuration information of the candidate target cell includes one or more of the following:

[0058] The cell identifier of the candidate target cell;

[0059] The cell offset of the candidate target cell;

[0060] The transmit power of the candidate target cell.

[0061] To solve the above technical problems, an embodiment of the present invention also provides a first node for cell switching, including: a first transceiver, monitoring a first cell and candidate target cells in a set of candidate target cells, and sending first information as a response to satisfying a first execution condition, wherein the first execution condition includes: a signal strength of the first cell is not higher than a first threshold; a second processor, switching to one of the candidate target cells as a response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is LTM without RACH; the set of candidate target cells is pre-configured.

[0062] As an embodiment, the candidate target cell set is pre-configured by the second node.

[0063] As an embodiment, monitoring the first cell and the candidate target cells in the candidate target cell set includes detecting each candidate target cell in the target cell set.

[0064] To solve the above technical problems, an embodiment of the present invention also provides a second node for cell switching, comprising: a first transmitter, receiving first information, wherein the first information is sent by the first node monitoring the first cell and the candidate target cells in the candidate target cell set as a response to satisfying the first execution condition, and the first execution condition comprises: the signal strength of the first cell received by the first node is not higher than a first threshold; a first processor, notifying at least one candidate target cell in the candidate target cell set, so that the first node switches to one of the candidate target cells in response to satisfying the second execution condition; wherein the first node switches to one of the candidate target cells depending on the sending of the first information; the switching is a non-RACH LTM; the candidate target cell set is pre-configured.

[0065] To solve the above technical problems, an embodiment of the present invention also provides a third node for cell switching, comprising: a receiving module, receiving notification information sent from a second node, the notification information including at least one candidate target cell in a candidate target cell set, the candidate target cell set being pre-configured by the second node to the first node, so that the first node monitors the first cell and the candidate target cells in the candidate target cell set, and sends first information to the second node as a response to satisfying a first execution condition; wherein the first execution condition comprises: the signal strength of the received first cell is not higher than a first threshold; the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH.

[0066] To solve the above technical problems, an embodiment of the present invention further provides a storage medium on which computer instructions are stored, and the computer instructions execute the steps of the above method when they are run. Optionally, an embodiment of the present invention further provides a cell switching device, including various modules or units for executing the method in any of the above possible implementations. Optionally, an embodiment of the present invention further provides a cell switching device, including a processor. The processor is coupled to a memory, and can be used to execute instructions in the memory to implement the method in any of the above possible implementations. Optionally, the cell switching device also includes a memory. Optionally, the cell switching device also includes a communication interface, and the processor is coupled to the communication interface.

[0067] To solve the above technical problem, an embodiment of the present invention further provides a terminal, including a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, and the processor executes the steps of the above method when executing the computer instructions.

[0068] To solve the above technical problems, an embodiment of the present invention further provides a network device, including a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, and the processor executes the steps of the above method when executing the computer instructions.

[0069] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0070] The embodiment of the present invention provides a method in a first node for cell switching, comprising: monitoring a first cell and each candidate target cell in a candidate target cell set, sending first information to a second node as a response to satisfying a first execution condition, wherein the first execution condition comprises: the signal strength of the received first cell is not higher than a first threshold; as a response to satisfying a second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is RACH-less LTM; the candidate target cell set is pre-configured by the second node. In the method provided by the embodiment of the present invention, the first node can be pre-configured with a candidate target cell set, and after monitoring the serving cell and the candidate target cell, it is determined whether the signal strength of the serving cell is higher than the first threshold, and then whether the first execution condition and the second execution condition are satisfied, and the first information is sent when the first execution condition is satisfied. Relying on sending the first information, under the condition of satisfying the second execution condition, based on executing LTM without RACH, the cell is switched to a suitable target cell. The method can realize cell switching triggered autonomously by UE, realize fast switching of L1 / L2 serving cells, and perform switching only when the dual execution conditions are met, thereby improving the switching robustness.

[0071] Furthermore, the above method eliminates the random access process, and only sends the first information when the first execution condition is met, and relies on sending the first information and LTM switching to the candidate target cell when the second execution condition is met. This can effectively avoid ping-pong switching and complete the switching through the protocol layers below L3, greatly reducing the switching delay.

[0072] Furthermore, in the above method, the first node autonomously initiates LTM cell switching without RACH after the first execution condition is met, rather than being initiated by the serving cell of the first node, which can further speed up the cell switching process.

[0073] As an embodiment, the above method can effectively support the demand for rapid cell switching caused by rapid channel changes and reduce service interruption time.

[0074] As an embodiment, the above method is particularly suitable for a mobility enhancement scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0076] Figure 1 A flow chart of a switching method in a first node according to an embodiment of the present invention is illustrated;

[0077] Figure 2 A schematic diagram illustrating a network architecture according to an embodiment of the present invention;

[0078] Figure 3 A schematic diagram illustrating a radio protocol architecture of a user plane and a control plane according to an embodiment of the present invention;

[0079] Figure 4 A hardware module schematic diagram of a communication device according to an embodiment of the present invention is illustrated;

[0080] Figure 5 An example of a wireless signal transmission flow chart according to an embodiment of the present invention is provided;

[0081] Figure 6 A schematic diagram of a part of steps in a switching method flow in a first node according to an embodiment of the present invention is illustrated;

[0082] Figure 7 A schematic diagram of a part of steps in a switching method flow in a first node according to an embodiment of the present invention is illustrated;

[0083] Figure 8 A schematic diagram illustrating detecting a cell after switching according to an embodiment of the present invention is illustrated;

[0084] Fig. 9 An example structural block diagram of a processing device in a first node according to an embodiment of the present invention is shown;

[0085] Fig.10 An example structural block diagram of a processing device in a second node according to an embodiment of the present invention is shown;

[0086] Fig.11 The structure block diagram of the processing device in the third node according to one embodiment of the present invention is illustrated. DETAILED DESCRIPTION

[0087] As mentioned in the background technology, in the prior art, mobility management such as cell switching has a variety of technical implementation forms, including layer 3 (L3) switching and layer 1 / layer 2 switching below layer 3. The development of conditional handover (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 layer 3 mobility (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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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 contention free random access (Contention Free Random Access, CFRA) through a physical downlink control channel command (Physical Downlink Control Channel, 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.

[0092] After the uplink synchronization is completed, the terminal device performs layer 1 (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 target cell based on the L1 measurement result. The source cell sends an LTM switching instruction to the terminal device.

[0093] The LTM switching instruction may be a Medium Access Control (MAC) control element (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, the TA may be included in the MAC CE.

[0094] 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.

[0095] For scenarios without RACH, when changing cells, the terminal device may not initiate a random access process in the candidate target cell. The uplink transmission resources of the candidate target cell can be indicated to the terminal device in the following ways:

[0096] Dynamic scheduling: The terminal obtains uplink authorization (i.e. dynamic grant) by monitoring the PDCCH of the target cell;

[0097] Semi-static scheduling: The network configures periodic uplink authorization (ie configured grant).

[0098] 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 network and UE. The network does not know when UE will switch, so the network has to reserve resources all the time, which will lead to resource waste. If resources are not reserved all the time, robustness problems will arise.

[0099] An embodiment of the present invention provides a method in a first node for cell switching, comprising: monitoring a first cell and each candidate target cell in a set of candidate target cells, and sending first information to a second node as a response to satisfying a first execution condition, wherein the first execution condition comprises: a signal strength received from the first cell is not higher than a first threshold; as a response to satisfying a second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is LTM without RACH; the set of candidate target cells is pre-configured by the second node.

[0100] In the method provided by the embodiment of the present invention, the first node can be pre-configured with a set of candidate target cells, and after monitoring the serving cell and the candidate target cells, it can determine whether the signal strength of its serving cell is higher than the first threshold, and then determine whether the first execution condition and the second execution condition are met, and send the first information when the first execution condition is met; and depending on sending the first information, when the second execution condition is met, the LTM cell is switched to a suitable target cell under the condition of no RACH. This method can realize cell switching triggered autonomously by UE, which is conducive to ensuring switching robustness, reducing resource waste, and improving resource utilization.

[0101] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and understandable, the specific embodiments of the present invention are 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 combined with each other at will without conflict.

[0102] In order to facilitate the clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, the words "first" and "second" are used to distinguish the same or similar items with basically the same functions and effects. For example, the first chip and the second chip are only used to distinguish different chips, and their order is not limited. Those skilled in the art can understand that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not necessarily limit them to be different.

[0103] It should be noted that in the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0104] Example 1

[0105] Embodiment 1 illustrates a flow chart of a switching method in a first node according to an embodiment of the present invention, as shown in the attached figure. Figure 1 The handover method is performed by a first node, for example, by a terminal device; or by a UE. The handover method may include the following steps:

[0106] Step S101, monitoring a first cell and each candidate target cell in a set of candidate target cells, and sending first information to a second node as a response to satisfying a first execution condition, wherein the first execution condition includes: a received signal strength of the first cell is not higher than a first threshold;

[0107] Step S102: In response to satisfying the second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information.

[0108] The switching is LTM without RACH; and the candidate target cell set is pre-configured by the second node.

[0109] Specifically, the first node may receive a candidate target cell set pre-configured by the second node before step S101. The candidate target cell set includes one or more candidate target cells. In one embodiment, the second node is a base station of the first cell. The first cell is a serving cell of the first node, and / or a primary serving cell of the first node, and / or a source cell for performing an LTM handover process.

[0110] As an embodiment, the configuration information of the candidate target cell may include one or more of the following: a cell identifier of the candidate target cell; a cell offset of the candidate target cell; and a transmission power of the candidate target cell.

[0111] In one embodiment, the handover refers to RACH-less LTM, or can be called RACH-less conditional LTM, or can be called RACH-less layer 1 / layer 2 triggered mobility cell handover. Conditional LTM refers to performing LMT cell handover based on UE triggering.

[0112] In step S101, after receiving the pre-configured candidate target cell set, the first node stores the configuration information of the candidate target cell set and the configuration information of each candidate target cell. The first node can monitor / measure the first cell and each candidate target cell in the candidate target cell set. The first node can report the measurement result in a conventional manner.

[0113] In one embodiment, when the measurement result shows that the signal strength of the first cell is lower than or equal to the first threshold, the first node determines that the first execution condition is met. At this time, the first node can send the first information to the first cell in response to meeting the first execution condition.

[0114] As an embodiment, the first information includes that the received signal strength is not higher than a first threshold. As a variant embodiment, the first information indicates that the received signal strength is not higher than the first threshold. The first information can trigger the execution of the LTM. In other words, the LTM depends on the sending of the first information. If the first information is not sent, the LTM will not be executed.

[0115] As an embodiment, the detecting of at least one candidate target cell in the candidate target cell set depends on the sending of the first information.

[0116] As an embodiment, in response to satisfying the second execution condition, switching to one of the candidate target cells depends on the sending of the first information.

[0117] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information includes: when the first information is not sent, the at least one candidate target cell will not switch to one of the candidate target cells if it satisfies the second execution condition.

[0118] As an embodiment, the switching to one of the candidate target cells depends on the sending of the first information, including: when the first information is not sent, there is no need to determine whether the at least one candidate target cell satisfies the second execution condition in order to switch to one of the candidate target cells.

[0119] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information includes: when the first information is not sent, there is no need to measure whether the at least one candidate target cell satisfies the second execution condition in order to switch to one of the candidate target cells.

[0120] In one embodiment, the first execution condition may include: the received signal strength of the first cell is not higher than a first threshold. In one embodiment, the first execution condition may include: the received signal strength of the first cell is not higher than the first threshold, and the received signal strength of at least one candidate target cell in the candidate target cell set is higher than a preset threshold, such as the first preset threshold.

[0121] In an embodiment, the signal strength of the first cell may be a channel quality of the first cell.

[0122] As an embodiment, the received signal strength of the first cell may be an average of one or more of the following: a measurement result of a reference signal; a signal strength of other signals except the reference signal; a signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0123] The measurement result of the reference signal may be a measurement result of a single reference signal or a measurement result of multiple reference signals. The reference signal includes but is not limited to SSB (Synchronization Signal Block) and CSI-RS (Channel Status Information-Reference Signal).

[0124] As an embodiment, the cell switching is performed in a protocol layer below layer 3. The protocol layer below layer 3 includes a MAC sublayer and a physical layer.

[0125] As a sub-embodiment of the above embodiment, the cell switching is performed at the MAC sublayer.

[0126] As a sub-embodiment of the above embodiment, the cell switching is performed at the physical layer.

[0127] As an embodiment, the first threshold value is a measured value, or a configured value, or a default value, or a value obtained by linearly processing the measured value and the configured value.

[0128] As an embodiment, when the signal strength of a cell is less than a threshold, the channel quality of the cell is worse than the threshold. Conversely, when the channel quality of a cell is greater than a threshold, the channel quality of the cell is better than the threshold.

[0129] As an embodiment, the signal strength of a cell is expressed by RSRP (Reference Signal Received Power), or RSRQ (Reference Signal Received Quality), or RSSI (Received Signal Strength Indicator), or SINR (Signal to Interference & Noise Ratio).

[0130] In an embodiment, the signal strength of the first cell may be a channel quality of the first cell, or may be a reference signal resource of the first cell, a signal strength of a beam, etc.

[0131] As an example, the signal strength of a cell is obtained by measuring the reference signal for the cell.

[0132] As an example, cell measurements are performed at a protocol layer below L3.

[0133] As an example, cell measurements are performed at L1; alternatively, cell measurements are performed at L1 and L3.

[0134] As an example, the signal strength of a cell is obtained by linearly processing the measurement value of the reference signal for the cell and a configured offset value. In a specific implementation, the configured offset value includes at least one of an offset value specific to a measurement object, an offset value specific to a cell, an offset value for an event, and a hysteresis parameter value for an event.

[0135] As an example, the signal strength of the first cell being worse than the first threshold includes: Mp < Mn; where Mp is the signal strength of the first cell; and the first threshold is Mn. In one implementation, Mn is the signal strength of a candidate target cell in the set of candidate target cells.

[0136] As an example, the signal strength of the first cell being worse than the first threshold includes: Mp < Thresh1; where Mp is the signal strength of the first cell; and the first threshold is Thresh1, and Thresh1 is configured.

[0137] As an example, the received signal strength of the first cell is lower than a second threshold; the second threshold is less than the first threshold.

[0138] As an example, the signal strength of the candidate target cell being better than the third threshold includes: Mn > Thresh3; where Mn is the signal strength of the candidate target cell; and the third threshold is Thresh3, and Thresh3 is configured.

[0139] As an example, the signal strength of the first cell being worse than the first threshold includes: Mn + Ofn + Ocn – Hys > Mp + Ofp + Ocp + Off; where the signal strength of the first cell is Mp + Ofp + Ocp + Off; the first threshold is Mn + Ofn + Ocn – Hys; Mp is the measurement result for the first cell; Ofp is the offset value specific to the measurement object for the first cell; Ocp is the cell-specific offset value for the first cell; Off is the offset value for the event; Mn is the measurement result for the candidate target cell; Ofn is the offset value specific to the measurement object for the candidate target cell; Ocn is the cell-specific offset value for the candidate target cell; Hys is the hysteresis parameter value for the event; when Mp and Mn are RSRP, the units of Mp and Mn are dBm (decibel milliwatt); when Mp and Mn are RSRQ or RS-SINR (reference signal signal-to-interference-plus-noise ratio), the units of Mp and Mn are dB (decibel); the units of Ofn, Ocn, Ofp, Ocp, Hys, and Off are dB.

[0140] As an example, the signal strength of the first cell being worse than the first threshold includes: Mp + Hys < Thresh1; where the signal strength of the first cell is Mp + Hys, the first threshold is Thresh1; Mp is the measurement result for the first cell; Hys is the hysteresis parameter value for the event; Thresh1 is configured.

[0141] As an example, the signal strength of the candidate target cell being better than the third threshold includes: the signal strength of the candidate target cell is Mn + Ofn + Ocn – Hys, the third threshold is Thresh3; where Mn is the measurement result for the candidate target cell; Ofn is the offset value specific to the measurement object for the candidate target cell; Ocn is the cell-specific offset value for the candidate target cell; Hys is the hysteresis parameter value for the event; Thresh3 is configured.

[0142] As an example, when Mp and Mn are RSRP, the units of Mp and Mn are dBm; when Mp and Mn are RSRQ or RS-SINR, the units of Mp and Mn are dB; the units of Ofn, Ocn, and Hys are dB, the unit of Thresh1 is the same as the unit of Mp; the unit of Thresh2 is the same as the unit of Mn.

[0143] As an embodiment, the first cell is a service cell of the first node.

[0144] As an embodiment, the first cell is a SpCell (Special Cell).

[0145] As an embodiment, the first cell is a PCell (Primary Cell).

[0146] As an embodiment, the first information is MAC CE (Control Element).

[0147] As an embodiment, the first information is physical layer information.

[0148] As an embodiment, the first information indicates that the received signal strength is not higher than the first threshold.As another embodiment, the first information carries at least one candidate target cell, such as an identifier of the candidate target cell.

[0149] In a specific implementation, after the second node receives the first information, the second node learns that the first node is going to perform a conditional LTM cell handover without RACH. Afterwards, the second node may notify at least one of the candidate target cells in the candidate target cell set so that at least one of the candidate target cells reserves resources for the first node to complete the LTM handover.

[0150] In one embodiment, the first information carries multiple candidate target cells. Under this condition, the second node learns that the first node intends to switch to one of the multiple candidate target cells through conditional LTM without RACH, and interacts with the multiple candidate target cells, so that the multiple candidate target cells reserve resources for the first node to enable the first node to select one of the candidate target cells and quickly complete the LTM switch.

[0151] In a preferred embodiment, the first information carries only one candidate target cell, under which condition, the second node learns that the first node intends to switch to the candidate target cell through conditional LTM without RACH, and exchanges information with the candidate target cell, so that the candidate target cell reserves resources for the first node so that the first node can quickly complete the LTM switch. In a specific implementation, the channel quality or signal strength of the candidate target cell is better than that of other candidate target cells.

[0152] As an embodiment, the first node may rely on satisfying the first execution condition to obtain the timing advance of the target cell after the handover. In a specific implementation, after satisfying the first execution condition, the first node may adopt a RACH-free solution. In an example, the first node may obtain the TA based on the RS, or based on the received timing difference, such as the RACH-free mechanism in LTE, UE-based TA measurement, etc.

[0153] As an embodiment, the first node needs to complete uplink synchronization with the candidate target cell before LTM switching.

[0154] As an embodiment, the first node may obtain the timing advance of the candidate target cell with the help of the first cell; or autonomously obtain the timing advance of the candidate target cell from the candidate target cell.

[0155] Assume that the value of the target timing advance is t; if the uplink transmission time slot of the uplink signal is n, the first node starts to send the uplink signal at a time t before the start time of the corresponding downlink time slot n.

[0156] As an embodiment, the value of the target timing advance is related to the subcarrier spacing of the uplink signal.

[0157] As an embodiment, the timing advance is a positive integer less than 4096; or, the value of the timing advance is 0, 1, 2, ..., 3846.

[0158] In step S102, in response to satisfying the second execution condition, the first node switches to one of the candidate target cells in response to sending the first information.

[0159] In a specific implementation, at least one candidate target cell includes only one candidate target cell. When the second execution condition is met, after the first node sends the first information, the LTM switches to the candidate target cell. In another specific implementation, when the second execution condition is met, after the first node sends the first information, the first node selects a candidate target cell with the best performance, and the LTM switches to the candidate target cell.

[0160] In one embodiment, the second execution condition includes: the received signal strength of the first cell is not higher than a second threshold.

[0161] In another embodiment, the second execution condition includes: the received signal strength of the candidate target cell is not less than a third threshold. In a specific implementation, the third threshold is greater than the first threshold.

[0162] In another embodiment, the second execution condition includes: the received signal strength of the first cell is not higher than a second threshold, and the received signal strength of the candidate target cell is not lower than a third threshold. In a specific implementation, the second threshold is less than the first threshold, and the third threshold is greater than the first threshold.

[0163] In a specific implementation, the second threshold is smaller than the first threshold. In a specific implementation, the first threshold is at a cell level, and the second threshold is at a beam level.

[0164] In another specific implementation, the first threshold is obtained by L3, and the second threshold is obtained by L1.

[0165] In another specific implementation, the first threshold is obtained by L3, and the second threshold and the third threshold are obtained by L1.

[0166] In another specific implementation, the first threshold is obtained by L3, and the third threshold is obtained by L1.

[0167] In yet another specific implementation, the first threshold is for multiple reference signal resources, and the second threshold and / or the third threshold is for one reference signal resource.

[0168] In yet another embodiment, the second execution condition includes: the received signal strength of the candidate target cell is not less than a third threshold. In a specific implementation, the third threshold is greater than the first threshold.

[0169] As an embodiment, after the first node switches to the candidate target cell, an uplink signal can be sent on the switched cell. In a specific implementation, after the first node completes the LTM switch, the switched cell is used as a new service cell, and physical layer signaling (such as DCI) carrying resource configuration is received from the new service cell.

[0170] In a specific implementation, the DCI includes resource configuration information. After receiving the DCI signaling, the first node may send the uplink signal in the switched cell based on the resource configuration information.

[0171] As an embodiment, the uplink signal may be uplink signaling, which is sent through PUCCH (Physical Uplink Control Channel). As another embodiment, the uplink signal may be uplink data, which is sent through PUSCH (Physical Uplink Shared Channel). Alternatively, the uplink signal may include uplink signaling and uplink data, which are sent through PUSCH.

[0172] As an embodiment, the air interface resources occupied by the uplink signal are indicated by the DCI signaling.

[0173] As an embodiment, the air interface resources occupied by the uplink signal are preconfigured.

[0174] As an embodiment, the air interface resources occupied by the uplink signal belong to the uplink configuration grant.

[0175] As an embodiment, the air interface resources include at least one of time domain resources, frequency domain resources, code domain resources or space resources.

[0176] As an embodiment, the timing advance is applied to the uplink wireless signal.

[0177] As an embodiment, the timing advance is applied to the uplink signal, including: the timing advance is used to determine a target timing advance value, the target timing advance value is an advance value of the start time of the uplink time unit for sending the uplink signal relative to the corresponding downlink time unit. The time unit is a frame, a subframe or a time slot, or a symbol.

[0178] Example 2

[0179] 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 (Long-Term Evolution) 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 terminology. 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 (BSS), an Extended Service Set (ESS), a TRP (Transmission Reception Point), or some other suitable term. 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 the 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.

[0180] As an embodiment, the UE201 corresponds to the first node in the present invention.

[0181] As an embodiment, the gNB203 corresponds to the second node and / or the third node in the present invention.

[0182] As an embodiment, the gNB203 is a macro cell base station.

[0183] As an embodiment, the gNB203 is a micro cell base station.

[0184] As an embodiment, the gNB203 is a pico cell base station.

[0185] As an embodiment, the gNB203 is a home base station (Femtocell).

[0186] As an embodiment, the gNB203 is a base station device that supports large delay difference.

[0187] As an embodiment, the gNB203 is a flying platform device.

[0188] As an embodiment, the gNB203 is a satellite device.

[0189] As an embodiment, the gNB203 is a testing device (e.g., a transceiver that simulates some functions of a base station, a signaling tester).

[0190] As an embodiment, the other gNB204 is a macro cell base station.

[0191] As an embodiment, the other gNB204 is a micro cell base station.

[0192] As an embodiment, the other gNB204 is a pico cell base station.

[0193] As an embodiment, the other gNB204 is a home base station (Femtocell).

[0194] As an embodiment, the other gNB204 is a base station device that supports a large delay difference.

[0195] As an embodiment, the other gNB204 is a flying platform device.

[0196] As an embodiment, the other gNB204 is a satellite device.

[0197] 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).

[0198] As an embodiment, the wireless link from the UE201 to the gNB203 is an uplink, and the uplink is used to perform uplink transmission.

[0199] As an embodiment, the wireless link from the gNB203 to the UE201 is a downlink, and the downlink is used to perform downlink transmission.

[0200] As an embodiment, the UE201 and the gNB203 are connected via a Uu interface.

[0201] Example 3

[0202] Embodiment 3 illustrates a schematic diagram of a wireless protocol architecture of a user plane and a control plane according to an embodiment of 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 of the control plane 300 of the UE and gNB is shown in three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1) is the lowest layer and implements various PHY (physical layer) signal processing functions. The L1 layer will be referred to as PHY 301 in this article. Layer 2 (L2 layer) 305 is above PHY 301 and is responsible for the link between the UE and the gNB through PHY 301. The L2 layer 305 includes the MAC sublayer 302, the RLC (Radio Link Control) sublayer 303, and the PDCP (Packet Data Convergence Protocol) sublayer 304, which terminate at the gNB on the network side. The PDCP sublayer 304 provides data encryption and integrity protection. The PDCP sublayer 304 also provides support for UE inter-zone mobility between gNBs. The RLC sublayer 303 provides segmentation and reassembly of data packets, realizes retransmission of lost data packets through ARQ, and also provides duplicate data packet detection and protocol error detection. The MAC sublayer 302 provides mapping between logical and transport channels and multiplexing of logical channel identities. The MAC sublayer 302 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell between UEs. The MAC sublayer 302 is also responsible for HARQ (Hybrid Automatic Repeat Request) operations. The RRC (Radio Resource Control) sublayer 306 in Layer 3 (L3 layer) in the control plane 300 is responsible for obtaining radio resources (i.e., radio bearers) and configuring lower layers using RRC signaling between the gNB and the UE. Although not shown in the figure, a V2X layer may also be provided above the RRC sublayer 306 in the control plane 300 of the UE. The V2X layer is responsible for generating a PC5 QoS parameter group and QoS rules according to the received service data or service request, generating a PC5 QoS flow corresponding to the PC5 QoS parameter group, and sending the PC5 QoS flow identifier and the corresponding PC5 QoS parameter group to the AS (Access Stratum) layer for the AS layer to perform QoS processing on the data packets belonging to the PC5 QoS flow identifier; the V2X layer also includes a PC5-S signaling protocol (PC5-SignalingProtocol) sublayer, and the V2X layer is responsible for indicating to the AS layer whether each transmission is a PC5-S transmission or a V2X service data transmission.The wireless protocol architecture of the user plane 350 includes layer 1 (L1 layer) and layer 2 (L2 layer). The wireless protocol architecture in the user plane 350 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 wireless transmission overhead. The L2 layer 355 in the user plane 350 also includes a SDAP (Service Data Adaptation Protocol) sublayer 356, which is responsible for mapping between QoS (Quality of Service) flows and data radio bearers (DRBs) to support the diversity of services. The wireless protocol architecture of the UE in the user plane 350 may include, at the L2 layer, a SDAP sublayer 356, a PDCP sublayer 354, a portion of or all of the protocol sublayers of the RLC sublayer 353 and the MAC sublayer 352. Although not shown, the UE may also have several upper layers above the L2 layer 355, including a network layer (e.g., an IP layer) terminated at the P-GW on the network side and an application layer terminated at the other end of the connection (e.g., a remote UE, a server, etc.).

[0203] As an example, Figure 3 The wireless protocol architecture in is applicable to the first node in the present invention.

[0204] As an example, Figure 3 The wireless protocol architecture in is applicable to the second node in the present invention.

[0205] As an example, Figure 3 The wireless protocol architecture in is applicable to the third node in the present invention.

[0206] As an embodiment, the first information in the present invention is generated by the MAC302 or the MAC352.

[0207] As an embodiment, the first information in the present invention is generated in the PHY301 or the PHY351.

[0208] As an embodiment, the uplink signal in the present invention is generated by the PHY301 or the PHY351.

[0209] As an embodiment, the RRC signaling in the present invention is generated in the RRC306.

[0210] As an embodiment, the RRC sublayer 306 in the L3 layer belongs to a higher layer.

[0211] Example 4

[0212] 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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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, 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.

[0219] 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: monitoring the first cell and each candidate target cell in the candidate target cell set, and sending first information to the network device as a response to satisfying a first execution condition, the first execution condition including: the signal strength of the received first cell is not higher than a first threshold; as a response to satisfying a second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is LTM without RACH; the candidate target cell set is pre-configured by the network device.

[0220] As an embodiment, the first communication device 450 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: monitoring the first cell and each candidate target cell in the candidate target cell set, and sending a first information to a network device as a response to satisfying a first execution condition, wherein the first execution condition includes: the signal strength of the received first cell is not higher than a first threshold; as a response to satisfying a second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is LTM without RACH; the candidate target cell set is pre-configured by the network device.

[0221] 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 first information, the first information is a first node monitoring the first cell and each candidate target cell in the candidate target cell set, and is sent as a response to satisfying a first execution condition, the first execution condition includes: the signal strength of the first cell received by the first node is not higher than a first threshold; notifies at least one candidate target cell in the candidate target cell set, so that the first node switches to one of the candidate target cells in response to satisfying the second execution condition; wherein the first node switches to one of the candidate target cells depending on the sending of the first information; the switching is LTM without RACH; the candidate target cell set is pre-configured.

[0222] 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: receiving first information, wherein the first information is a first node monitoring a first cell and each candidate target cell in a set of candidate target cells, and is sent as a response to satisfying a first execution condition, wherein the first execution condition includes: the signal strength of the first cell received by the first node is not higher than a first threshold; notifying at least one candidate target cell in the set of candidate target cells so that the first node switches to one of the candidate target cells in response to satisfying the second execution condition; wherein the first node switches to one of the candidate target cells depending on the sending of the first information; the switching is LTM without RACH; the set of candidate target cells is pre-configured.

[0223] 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 notification information sent from the second node, the notification information includes at least one candidate target cell in the candidate target cell set, the candidate target cell set is pre-configured by the second node to the first node, so that the first node monitors the first cell and each candidate target cell in the candidate target cell set, and sends first information to the second node as a response to satisfying a first execution condition; wherein the first execution condition includes: the signal strength of the received first cell is not higher than a first threshold; the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH.

[0224] 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: receiving notification information from the second node, the notification information including at least one candidate target cell in a candidate target cell set, and the candidate target cell set is pre-configured by the second node to the first node, so that the first node monitors the first cell and each candidate target cell in the candidate target cell set, and sends first information to the second node in response to satisfying a first execution condition; wherein the first execution condition includes: the signal strength of the received first cell is not higher than a first threshold; the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH.

[0225] As an embodiment, the first communication device 450 corresponds to the first node in the present invention.

[0226] As an embodiment, the second communication device 410 corresponds to the second node in the present invention.

[0227] As an embodiment, the second communication device 410 corresponds to the third node in the present invention.

[0228] As an embodiment, the first communication device 450 is a UE.

[0229] As an embodiment, the first communication device 450 is a relay.

[0230] As an embodiment, the second communication device 410 is a base station device.

[0231] As an embodiment, the second communication device 410 is a distribution unit of a base station.

[0232] As an embodiment, the second communication device 410 is a piece of code in a distributed unit of a base station.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] Example 5

[0240] 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.

[0241] for First node N51 , receiving RRC signaling in step S511; monitoring the first cell and each candidate target cell in the candidate target cell set in step S512; sending first information in step S513; switching to one of the candidate target cells in response to satisfying the second execution condition in step S514; receiving DCI in step S515; and sending an uplink signal in step S516.

[0242] for Second node N52 , sending RRC signaling in step S521; receiving first information in step S522; and exchanging signaling with the third node N53 in step S531.

[0243] for The third node N53 , in step S531, signaling is exchanged with the second node N52, in step S532, DCI is sent; and in step S533, an uplink signal is received.

[0244] In Embodiment 5, the second node N52 sends RRC signaling to the first node N51 in step S521.

[0245] As an embodiment, the RRC signaling includes a candidate target cell configuration IE (Information element).

[0246] As an embodiment, the RRC signaling configures a candidate cell configuration for the candidate target cell set.

[0247] As an embodiment, the RRC signaling configures a candidate target cell configuration for each candidate target cell in the candidate target cell set, and each candidate target cell configuration is indicated by a configuration identifier.

[0248] As an embodiment, the candidate target cell set is an LTM candidate target cell set.

[0249] As an embodiment, the candidate target cell configuration is an LTM candidate target cell configuration.

[0250] As an embodiment, the candidate target cell configuration is a partial or complete LTM candidate target cell configuration.

[0251] As an embodiment, the RRC signaling is RRCReconfiguration (RRC reconfiguration, or condRRCReconfig (conditional RRC reconfiguration); or ltm-ReferenceConfiguration (LTM reference configuration).

[0252] As an embodiment, the RRC signaling includes LTM-Candidate (LTM candidate); or, the RRC signaling includes ltm-CandidateConfig (LTM candidate configuration); or, the ltm-CandidateConfig included in the RRC signaling is a complete LTM candidate cell configuration configured for the LTM candidate target cell set.

[0253] As an embodiment, the ltm-ReferenceConfiguration and the ltm-CandidateConfig included in the RRC signaling generate a complete LTM candidate target cell configuration and configure it to the LTM candidate target cell set.

[0254] As an embodiment, the candidate target cell set is configured according to the measurement report reported by the first node N51.

[0255] As an embodiment, the candidate target cell set is configured by the second node N52, which is configured by the base station of the first cell.

[0256] As an embodiment, the second cell belongs to the candidate target cell set.

[0257] As an embodiment, the candidate target cell is used for cell switch.

[0258] As an embodiment, the candidate target cell is used for LTM.

[0259] As an embodiment, the RRC signaling indicates the second cell. In one implementation, the second cell is identified by a PhysCellId (physical cell identifier). Alternatively, the second cell is identified by a candidateCellID (candidate target cell identifier).

[0260] As an embodiment, the RRC signaling configures the candidate target cell configuration for the second cell.

[0261] As an embodiment, the second cell is any cell in a set of candidate target cells configured for the first node N51; wherein the set of candidate target cells configured for the first node N51 includes at least one cell.

[0262] As an embodiment, the base station of the first cell and the base station of the candidate target cell are the same base station.

[0263] As an embodiment, the base station of the first cell and the base station of the candidate target cell are different base stations.

[0264] As an embodiment, the candidate target cell is a candidate target cell of the first node.

[0265] As an embodiment, the candidate target cell is the LTM candidate target cell of the first node N51.

[0266] As an embodiment, the evaluating whether the first execution condition is met includes: performing channel measurement to evaluate signal strength for each candidate target cell in the candidate target cell set; wherein the third node N53 is a base station of any candidate target cell in the candidate target cell set.

[0267] As an embodiment, after receiving the RRC signaling and before determining that the first execution condition is met, the first node is in an RRC connected (RRC_connected) state.

[0268] As an embodiment, the first RRC signaling indicates the first threshold.

[0269] As an embodiment, the first RRC signaling includes the first threshold, or includes the second threshold; or includes the above-mentioned first threshold and second threshold.

[0270] As an embodiment, the RRC signaling indicates the first execution condition; or indicates the second execution condition; or indicates the first execution condition and the second execution condition.

[0271] As a variant embodiment, the first execution condition and the second execution condition are sent through different RRC signaling.

[0272] As an embodiment, the RRC signaling configures an event in which conditional LTM is executed.

[0273] As an embodiment, after the RRC signaling is received, the configurations of the candidate target cells included therein are stored.

[0274] As an embodiment, the RRC signaling also includes a first threshold, a second threshold and / or a third threshold.

[0275] As another embodiment, the first threshold is sent by other RRC signaling, and is received and stored by the first node N51. Alternatively, one or more of the first threshold, the second threshold and / or the third threshold is sent by other same RRC signaling; or, the first threshold, the second threshold and / or the third threshold is sent by other different RRC signaling, and is then received and stored by the first node N51.

[0276] In one embodiment, the RRC signaling includes the candidate target cell set and is configured to the first node N51. The configuration information of the candidate target cell may include one or more of the following: the cell identifier of the candidate target cell; the cell offset of the candidate target cell; and the transmit power of the candidate target cell.

[0277] In a specific implementation, step S511 and step S512 may be executed in parallel or sequentially, or step S512 may be executed first and step S511 may be executed later.

[0278] In a specific implementation, the first node N51 receives RRC signaling in step S511. After receiving the RRC signaling, the first node N51 stores the configuration information in the RRC signaling. In step S512, the first node N51 monitors the first cell and each candidate target cell in the candidate target cell set.

[0279] As an embodiment, after the RRC signaling is received and before the first execution condition is met, the various candidate target cell configurations included in the RRC signaling are not applied.

[0280] In a specific implementation, the first node N51 may be in an RRC connected state. The first node N51 monitors the first cell to obtain the signal strength of the first cell, for example, monitoring the reference signal (RS) of the base station second node N52 of the first cell, such as SSB and / or CSI-RS.

[0281] As an embodiment, the signal strength of the first cell may be the channel quality of the first cell, or may be a reference signal resource of the first cell, a signal strength of a beam, etc. The monitoring of the first cell may be a measurement of the first cell, which is an L3 measurement.

[0282] In a specific implementation, the first node N51 may measure the RS of the second node N52, and may also measure the RS of each candidate target cell in the candidate target cell set to obtain the signal strength of the first cell and each candidate target cell. For example, the SSB or CSI-RS may be measured to obtain the signal strength of each cell.

[0283] As an embodiment, the first threshold is a cell-level measurement result, and the second threshold is a beam-level measurement result. In one implementation, the first threshold may be a L3 threshold, and the second threshold may be a L1 threshold. In another implementation, the first threshold is for multiple RS resources, and the second threshold is for one RS resource.

[0284] In one embodiment, the signal strength received by the first node N51 is lower than or equal to the first threshold. For example, the signal strength or channel quality obtained by measuring SSB or CSI-RS is lower than or equal to the first threshold. At this time, the first execution condition is met.

[0285] If the first execution condition is met, then in step S513, the first node N51 sends the first information to the second node N52. The first information may indicate that the received signal strength is not higher than a first threshold.

[0286] In one embodiment, the first information may indicate that the received signal strength of the first cell is not higher than a first threshold; or, the first information may indicate that the received signal strength of the first cell is not higher than the first threshold and the received signal strength of at least one of the candidate target cells is higher than the first threshold; or, the first information may indicate that the received signal strength of the first cell is not higher than the first threshold, and the received signal strength of at least one of the candidate target cells is higher than the third threshold, and the third threshold is greater than the first threshold.

[0287] Depending on the sending of the first information, the first node N51 will perform LTM switching without RACH conditions; or, depending on the sending of the first information, the first node N51 will have a high probability of performing LTM switching without RACH conditions.

[0288] As an embodiment, depending on whether the first execution condition is satisfied, the first node N51 obtains the timing advance of the target cell after switching.

[0289] As an embodiment, when the base station of the first cell and the base station of the candidate target cell are different base stations, the timing advance is acquired in one of the base stations of the candidate target cell, and then forwarded to the base station of the first cell through a backhaul network (backhaul), and sent to the first node through the first cell. This method does not receive the timing advance command in the second cell, which can reduce the communication interruption time with the first cell. The backhaul network is ideal. Or, the backhaul network is non-ideal.

[0290] For example, the timing advance is obtained at the third node N53, then forwarded to the second node N52 through the backhaul network, and sent to the first node N51, at which time the first node N51 obtains the timing advance.

[0291] After step S512, the first node N51 selects one or more suitable candidate target cells and sends the first information in step S513.

[0292] In one embodiment, the first information may indicate LTM cell switching without RACH conditions. For example, the first information includes 1 bit to indicate whether LTM cell switching without RACH conditions is performed. When LTM cell switching without RACH conditions is indicated, the second node N52 receiving the first information can know that the first node N51 meets the first execution condition.

[0293] Next, the second node N52 receives the first information in step S522. Afterwards, the second node N52 and the third node N53 perform step S531 to perform interactive signaling. In a specific implementation, the interactive signaling includes the second node N52 sending notification information to the third node N53 to notify at least one candidate target cell in the candidate target cell set, so that the first node N51 can switch to one of the candidate target cells in response to satisfying the second execution condition. Among them, the notification information may include at least one candidate target cell in the candidate target cell set. For example, the at least one candidate target cell may be the ID of each candidate target cell. The at least one candidate target cell may be obtained by the first node through the first information. It should be noted that step S531 is a signaling interaction between cells.

[0294] In a specific implementation, the switching to one of the candidate target cells depends on the sending of the first information.

[0295] Preferably, the at least one candidate target cell has only one candidate target cell, the signal strength or channel quality of the only candidate target cell is the best in the candidate target cell set, or the signal strength or channel quality of the only candidate target cell is a candidate target cell that meets a preset threshold.

[0296] After receiving the notification information sent by the second node N52, the third node N53 reserves resources for the first node N51, so that the first node N51 switches the LTM cell without RACH conditions to the candidate target cell to which the third node N53 belongs. The candidate target cell to which the third node N53 belongs is one of the at least one candidate target cell reported by the first node N51.

[0297] In one implementation, the third node N53 performs signaling interaction with the second node N52 to prepare for completing the conditional LTM of the first node N51.

[0298] In specific implementation, the third node N53 may send a PDCCH. For example, in step S532, a DCI is sent, where the DCI includes resource configuration information, such as an uplink grant (UL grant).

[0299] During this period, the first node N51 may continue to determine the signal strength of the first cell and / or the second cell after step S513. In step S514, in response to satisfying the second execution condition, switching to one of the candidate target cells is performed.

[0300] As an embodiment, satisfying the second execution condition includes that the signal strength of the first cell received is not higher than a second threshold. Alternatively, satisfying the second execution condition includes that the signal strength of at least one candidate target cell is not lower than a third threshold. Alternatively, satisfying the second execution condition includes that the signal strength of the first cell received is not higher than the second threshold, and the signal strength of at least one of the candidate target cells is not lower than a third threshold.

[0301] In a specific implementation, the second threshold is not higher than the first threshold; and the third threshold is higher than the first threshold.

[0302] As an embodiment, the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information.

[0303] As an embodiment, the switching to one of the candidate target cells depends on the sending of the first information, which means that the sending of the first information will trigger the first node to switch to one of the candidate target cells. If the first information is not sent, the first node will not perform the switching.

[0304] As an embodiment, the switching to one of the candidate target cells being dependent on the sending of the first information means that the time interval between the sending time of the first information and the switching is very small.

[0305] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information means that after sending the first information, starting to evaluate whether the second execution condition set is satisfied to perform the switching.

[0306] As an embodiment, the switching to one of the candidate target cells depending on the sending of the first information refers to starting a timer when sending the first information, and detecting the switched cell when the timer expires. For example, detecting the uplink grant of the switched cell to obtain uplink resources.

[0307] As an embodiment, after the first execution condition is met, the first node N51 can perform uplink synchronization with one of the at least one candidate target cell. Preferably, the first information carries one of the candidate target cells, and the first node N51 autonomously obtains the timing of the candidate target cell to complete uplink synchronization in advance.

[0308] In this embodiment, the first node N51 configures multiple execution conditions. After the first execution condition is met, the first information is sent to the serving cell (e.g., the first cell). After the serving cell receives the first information, the resources of the target cell or candidate target cell can be activated through signaling interaction between cells, thereby quickly completing the UE autonomous LTM switching, which is conducive to saving resources.

[0309] In specific implementation, the first node N51 can configure the first threshold, the second threshold and / or the third threshold, and after meeting the first threshold configured by RRC, send the first information to the serving cell, and activate the resources of the target cell or the candidate target cell after the serving cell receives the first information, thereby completing the switching, which is conducive to saving resources.

[0310] In step S515, the first node N51 receives the DCI. In a specific implementation, the first node N51 detects the cell after the handover to receive the resource configuration information carried by the DCI.

[0311] As an embodiment, the detecting of the switched cell includes: the first node N51 performs LTM switching to the switched cell by itself.

[0312] As an embodiment, the detecting of the switched cell includes: the first node N51 automatically performs switching of layers below layer 3 to the switched cell.

[0313] As an embodiment, the detecting of the switched cell includes: releasing the RRC configuration for the first cell.

[0314] As an embodiment, the detecting of the switched cell includes: L2 of the first node N51 is reset.

[0315] In step S516, the first node N51 sends an uplink signal. In a specific implementation, after receiving the resource configuration information carried in the DCI sent by the third node N53, the first node N51 can send an uplink signal in the cell to which the third node N53 belongs based on the resource configuration information. A PUSCH signal can be sent, or a PUCCH signal can be sent. Accordingly, the third node N53 receives the uplink signal in step S533.

[0316] About Attachment Figure 5 For more information on the working principle and working method, please refer to the above Figure 1 The relevant description of the technical solution is shown in the figure and will not be repeated here.

[0317] Example 6

[0318] Attached Figure 6A schematic diagram of some steps in a switching method flow in a first node according to an embodiment of the present invention is illustrated.

[0319] Combination Figure 5 After step S512, the first node N51 determines that the first execution condition is met, and after executing step S513 to send the first information, executes step S601. In step S601, the first node N51 evaluates whether the second execution condition is met.

[0320] In one embodiment, the first node N51 does not meet the second execution condition, and the first node executes step S602 to send the second information to the node N52.

[0321] In one embodiment, the second information indicates that the second execution condition is not satisfied. At this time, the candidate target cell may release resources reserved for the first node N51 to save resources.

[0322] In another embodiment, the second information indicates to stop the handover. At this time, the candidate target cell may release the resources reserved for the first node N51 to save resources.

[0323] As an embodiment, whether to evaluate whether the second execution condition is satisfied depends on whether the first information is sent by the first node.

[0324] As a variant embodiment, whether to evaluate whether the second execution condition is satisfied depends on whether the first execution condition is satisfied. If the first execution condition is not satisfied, the first node does not send the first information and does not evaluate the second execution condition information.

[0325] As an embodiment, depending on whether the first execution condition is satisfied, the first node may obtain the timing advance of the target cell after the handover.

[0326] As a variant embodiment, when the first execution condition is not met, it is not required to obtain the timing advance of the first cell.

[0327] As an embodiment, after the first information is sent, the first node may obtain the timing advance of the at least one candidate target cell.

[0328] As an embodiment, the first node performs uplink synchronization to one of the candidate target cells before switching to the candidate target cell.

[0329] In specific implementation, during the uplink synchronization process for each candidate cell, if the RRC reconfiguration information indicates that the terminal device itself measures the timing advance, then the terminal device can measure the timing advance of the source cell, and determine the timing advance of the candidate cell based on the reception time difference between the source cell and the candidate cell; or, the source cell triggers CFRA through a PDCCH order (PDCCH command) to obtain the timing advance of the candidate cell, and the terminal device initiates CFRA to the candidate cell to obtain the timing advance of the candidate cell, and then the source cell determines the validity of the timing advance.

[0330] Example 7

[0331] Figure 7 A schematic diagram of some steps in a switching method flow in a first node according to an embodiment of the present invention is illustrated.

[0332] Combination Figure 5 , after step S512, the first node N51 determines that the first execution condition is not met.

[0333] As an embodiment, the first node N51 executes step S701 and sends second information. The second information sent to the second node N52 indicates that the first execution condition is not satisfied.

[0334] As an embodiment, the second information indicates that the received signal strength of the first cell is higher than a first threshold.

[0335] In a specific implementation, after sending the second information, the evaluation of whether the second execution condition is satisfied is stopped.

[0336] In a specific implementation, the second information is carried by a high-layer signaling, such as an RRC signaling; or, the second information is carried by a signaling below L3, such as a MAC CE or a physical layer signaling.

[0337] Example 8

[0338] Figure 8 A schematic diagram of detecting a cell after switching according to an embodiment of the present invention is illustrated.

[0339] As an embodiment, the first node starts a timer when sending the first information in step S801, and detects a switched cell after the timer expires in step S802.

[0340] As an embodiment, when the second execution condition is met, the switched cell is detected when the timer expires.

[0341] As an embodiment, starting the timer includes: setting the value of the timer to an initial value; wherein the initial value is 0, or the initial value is a preset expiration value.

[0342] As an embodiment, the preset expiration value is preconfigured.

[0343] As an embodiment, the preset expiration value is network configured.

[0344] As an embodiment, the preset expiration value is used to determine the expiration of the timer.

[0345] As an embodiment, the timer is in a running state after being started.

[0346] As an embodiment, the timer is maintained at a higher layer, which is an RRC layer or a MAC layer.

[0347] As an embodiment, the sending time of the first information is earlier than the starting time of the timer.

[0348] As an embodiment, the timer is used to detect the switched cell.

[0349] As an embodiment, after the cell switching is successful, the timer is stopped. In other words, when the timer expires, the cell switching has been completed.

[0350] As an embodiment, when the timer expires, the first node starts blind detection of the switched cell.

[0351] As an embodiment, if the cell switching is terminated, the timer is stopped.

[0352] As an embodiment, when HARQ is received at the third node, it is determined that the uplink signal is successfully received by the three nodes.

[0353] As an embodiment, the initial value of the timer is 0, and updating the timer is to add 1 to the value of the timer; when the value of the timer is a preset expiration value, the timer expires and the timer is reset to 0.

[0354] As an embodiment, the initial value of the timer is a preset expiration value, and updating the timer is to reduce the value of the timer by 1; when the value of the timer is 0, the timer expires. The timer is reset to the preset expiration value.

[0355] As an embodiment, when the timer is running, the timer is updated at each time interval. Each time interval is 1 millisecond; or is the duration of a time slot.

[0356] As an embodiment, when the timer is running, if the stop condition of the timer is met, the timer is stopped.

[0357] Example 9

[0358] Embodiment 9 illustrates a structural block diagram of a processing device in a first node according to an embodiment of the present invention, as shown in the attached figure. Fig. 9 As shown in the attached Fig. 9 In the embodiment, the first node processing device 900 includes a first processor 901 and a second processor 902; the first node 900 is a UE. In a specific implementation, the first processor 901 and the second processor 902 can be the same processing module or different processing modules.

[0359] In Example 9, the first node processing device 900 includes: the first processor 901, monitoring the first cell and the candidate target cells in the candidate target cell set, and sending first information as a response to satisfying the first execution condition, the first execution condition including: the signal strength of the first cell is not higher than a first threshold; the second processor 902, switching to one of the candidate target cells as a response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; wherein the switching is LTM without RACH; the candidate target cell set is pre-configured.

[0360] As an embodiment, monitoring the first cell and the candidate target cells in the candidate target cell set includes monitoring at least one candidate target cell in the candidate target cell set.

[0361] As an embodiment, monitoring the first cell and the candidate target cells in the candidate target cell set includes monitoring each candidate target cell in the candidate target cell set.

[0362] As an embodiment, monitoring the first cell and the candidate target cells in the candidate target cell set includes measuring the signal strength of the first cell.

[0363] As an embodiment, monitoring the first cell and the candidate target cells in the candidate target cell set includes measuring signal strengths of the candidate cells in the candidate target cell set.

[0364] As an embodiment, the first information carries at least one candidate target cell in the candidate target cell set.

[0365] As an embodiment, the first processor 901 may start a timer when sending the first information, and detect the switched cell when the timer expires.

[0366] In one embodiment, the first processor 901 may receive resource configuration information sent by the switched cell, and send an uplink signal on the switched cell based on the resource configuration information.

[0367] In a specific implementation, the signal strength of the first cell may be at least one of the following: a measurement result of a reference signal; a signal strength of other signals except the reference signal; a signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0368] In one embodiment, the candidate target cell set may be pre-configured via RRC signaling; the configuration information of the candidate target cells includes one or more of the following: a cell identifier of the candidate target cell; a cell offset of the candidate target cell; and a transmission power of the candidate target cell.

[0369] As an embodiment, the first processor 901 may obtain the timing advance of the target cell after switching depending on whether the first execution condition is satisfied.

[0370] As an embodiment, the first processor 901 includes the appended Figure 4 The receiver 454 (including antenna 452), receive processor 456, multi-antenna receive processor 458 and controller / processor 459.

[0371] As an embodiment, the first processor 901 includes the appended Figure 4 At least one of the receiver 454 (including antenna 452), receive processor 456, multi-antenna receive processor 458 or controller / processor 459.

[0372] As an embodiment, the second processor 902 includes the attached Figure 4 The receiver 454 (including antenna 452), receive processor 456, multi-antenna receive processor 458 and controller / processor 459.

[0373] As an embodiment, the second processor 902 includes the attached Figure 4 At least one of the receiver 454 (including antenna 452), receive processor 456, multi-antenna receive processor 458 or controller / processor 459.

[0374] For more information about the working principle and working method of the first node processing device 900, 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.

[0375] Example 10

[0376] Embodiment 10 illustrates a structural block diagram of a processing device in a second node according to an embodiment of the present invention, as shown in the attached figure. Fig.10 As shown in the attached Fig.10 In the embodiment, the first node processing device 1000 includes a first receiver 1001 and a first processor 1002; the second node 1000 is a network device, such as an NR base station. The first receiver 1001 and the first processor 1002 can be the same processing module or different processing modules.

[0377] In embodiment 10, the first node processing device 1000 includes: the first receiver 1001 can receive first information, the first information is the first node monitoring the first cell and the candidate target cell in the candidate target cell set, and is sent as a response to satisfying the first execution condition, the first execution condition includes: the signal strength of the first cell measured by the first node is not higher than the first threshold; the first processor 1002 notifies at least one candidate target cell in the candidate target cell set, so that the first node switches to one of the candidate target cells in response to satisfying the second execution condition; wherein, the first node switches to one of the candidate target cells depending on the sending of the first information; the switching is a non-RACH LTM; the candidate target cell set is pre-configured.

[0378] As an embodiment, the first information carries at least one candidate target cell in the candidate target cell set.

[0379] As an embodiment, the received signal strength of the first cell may be at least one of the following: a measurement result of a reference signal; a signal strength of other signals except the reference signal; a signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

[0380] As an embodiment, the candidate target cell set is pre-configured through RRC signaling; the configuration information of the candidate target cell may include one or more of the following: the cell identifier of the candidate target cell; the cell offset of the candidate target cell; the transmission power of the candidate target cell.

[0381] As an embodiment, the first receiver 1001 includes the appended Figure 4The receiver 418 (including antenna 420), receive processor 470, multi-antenna receive processor 472 and controller / processor 475.

[0382] As an embodiment, the first receiver 1001 includes the appended Figure 4 At least one of the receiver 418 (including the antenna 420), the receive processor 470, the multi-antenna receive processor 472 or the controller / processor 475.

[0383] As an embodiment, the first processor 1002 includes the appended Figure 4 The transmitter 418 (including antenna 420), transmit processor 416, multi-antenna transmit processor 471 and controller / processor 475.

[0384] As an embodiment, the first processor 1002 includes the appended Figure 4 At least one of the transmitter 418 (including antenna 420), the transmit processor 416, the multi-antenna transmit processor 471 or the controller / processor 475.

[0385] For more information about the working principle and working method of the second node processing device 1000, 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.

[0386] Embodiment 11

[0387] Embodiment 11 illustrates a structural block diagram of a processing device in a third node according to an embodiment of the present invention, as shown in the attached figure. Fig.11 As shown in the attached Fig.11 In the present invention, the third node processing device 1100 includes a first receiver 1101; the third node processing device 1100 is a network device, such as an NR base station.

[0388] In a specific implementation, the third node processing device 1100 may include: a first receiver 1101 may receive notification information sent from a second node, the notification information including at least one candidate target cell in a candidate target cell set, the candidate target cell set being pre-configured by the second node to the first node, so that the first node monitors the first cell and the candidate target cells in the candidate target cell set, and sends first information to the second node in response to satisfying a first execution condition; wherein the first execution condition includes: a signal strength of the first cell is not higher than a first threshold; the first node switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH.

[0389] As an embodiment, the first receiver 1101 includes the appended Figure 4 The receiver 418 (including antenna 420), receive processor 470, multi-antenna receive processor 472 and controller / processor 475.

[0390] As an embodiment, the first receiver 1101 includes the appended Figure 4 At least one of the receiver 418 (including the antenna 420), the receive processor 470, the multi-antenna receive processor 472 or the controller / processor 475.

[0391] For more information about the working principle and working method of the third node processing device 1100, 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.

[0392] 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 first type of communication node or UE or terminal in the present invention includes but is not limited to mobile phones, tablet computers, notebooks, Internet cards, low-power devices, eMTC (enhanced Machine Type Communication, enhanced machine type communication) equipment, NB-IoT equipment, vehicle-mounted communication equipment, aircraft, airplanes, drones, remote-controlled aircraft and other wireless communication equipment. The second type of communication node or base station or network side equipment in the present invention includes but is not limited to macrocellular base stations, microcellular base stations, home base stations, relay base stations, eNB, gNB, transmission and reception nodes TRP (Transmission and Reception Point, transmission and reception point), relay satellites, satellite base stations, aerial base stations and other wireless communication equipment.

[0393] 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 cell switching, characterized in that: include: A first processor monitors a first cell and a candidate target cell in a set of candidate target cells, and sends first information in response to satisfying a first execution condition, wherein the first execution condition includes: a signal strength of the first cell is not higher than a first threshold; The second processor switches to one of the candidate target cells in response to satisfying the second execution condition; the switching to one of the candidate target cells depends on the sending of the first information; The switching is LTM without RACH; and the candidate target cell set is pre-configured.

2. The first node according to claim 1, characterized in that: The first information indicates at least one candidate target cell in the candidate target cell set.

3. The first node according to claim 1 or 2, characterized in that: The first processor starts a timer when sending the first information, and detects the switched cell when the timer expires.

4. The first node according to claim 3, characterized in that: include: The first processor receives resource configuration information sent by the switched cell, and sends an uplink signal on the switched cell based on the resource configuration information.

5. The first node according to any one of claims 1 to 4, characterized in that: The signal strength of the first cell is at least one of the following: Measurement results of reference signals; signal strengths of other signals except the reference signal; The signal strength of other signals except the reference signal, and within a preset time interval, the signal strength of the other signals is not higher than the first threshold.

6. The first node according to any one of claims 1 to 5, characterized in that: The candidate target cell set is pre-configured through RRC signaling; the configuration information of the candidate target cell includes one or more of the following: The cell identifier of the candidate target cell; The cell offset of the candidate target cell; The transmit power of the candidate target cell.

7. The first node according to any one of claims 1 to 6, characterized in that: The first processor obtains the timing advance of the cell after switching depending on whether the first execution condition is satisfied.

8. A second node for cell switching, characterized in that: include: A first transceiver receives first information, where the first information is sent by a first node monitoring a first cell and a candidate target cell in a set of candidate target cells as a response to satisfying a first execution condition, where the first execution condition includes: a signal strength of the first cell is not higher than a first threshold; The first processor notifies at least one candidate target cell in the candidate target cell set, so that the first node switches to one of the candidate target cells in response to satisfying a second execution condition; The switching of the first node to one of the candidate target cells depends on the sending of the first information; the switching is LTM without RACH; and the candidate target cell set is pre-configured.

9. A method in a first node for cell switching, characterized in that: include: monitoring a first cell and a candidate target cell in a set of candidate target cells, and sending first information as a response to satisfying a first execution condition, wherein the first execution condition includes: a signal strength of the first cell is not higher than a first threshold; In response to satisfying the second execution condition, switching to one of the candidate target cells; the switching to one of the candidate target cells depends on the sending of the first information; The switching is non-RACH LTM; the candidate target cell set is pre-configured.

10. A method in a second node for cell switching, characterized in that: include: receiving first information, where the first information is sent by the first node monitoring the first cell and the candidate target cell in the candidate target cell set as a response to satisfying a first execution condition, where the first execution condition includes: a signal strength of the first cell received by the first node is not higher than a first threshold; Notifying at least one candidate target cell in the candidate target cell set, so that the first node switches to one of the candidate target cells in response to satisfying a second execution condition; The switching of the first node to one of the candidate target cells depends on the sending of the first information; the switching is a non-RACH LTM; and the candidate target cell set is pre-configured.

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