Method and device in node for wireless communication

Abstract

Provided are a method and device in a node for wireless communication. The method comprises: receiving first information, wherein the first information is used for determining a valid period of a first PRACH resource of a target cell; and within the valid period of the first PRACH resource, using the first PRACH resource to initiate random access to the target cell.

Description

Methods and apparatus for nodes used in wireless communication Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a method and apparatus for a node used in wireless communication. Background Technology

[0002] The random access procedure refers to the process from when a terminal device attempts to access the network by sending a random access preamble through the physical random access channel (PRACH) to when a basic signaling connection is established with the network. This process is a crucial step in establishing the initial communication connection between the terminal device and the network. Therefore, improving the performance of PRACH transmission is a problem that needs to be solved. Summary of the Invention

[0003] This application provides a method and apparatus for use in a node for wireless communication. Various aspects of this application will be described below.

[0004] In a first aspect, a method for a first node in wireless communication is provided, comprising: receiving first information, the first information being used to determine a valid period of a first PRACH resource of a target cell; and, within the valid period of the first PRACH resource, initiating random access to the target cell using the first PRACH resource.

[0005] In a second aspect, a method for a first node in wireless communication is provided, comprising: receiving second information, the second information including first PRACH resource information and second PRACH resource information of a target cell; the first PRACH resource information being a temporary PRACH resource and the second PRACH resource information being a regular PRACH resource; the second information including first indication information, the first indication information being used to determine the effective time period of the first PRACH resource of the target cell; determining a target PRACH resource from the first PRACH resource and the second PRACH resource; and initiating random access to the target cell through the target PRACH resource.

[0006] Thirdly, a method for a second node in wireless communication is provided, comprising: receiving third information from a target cell, the third information including first PRACH resource information of the target cell and a valid period of the first PRACH resource; sending first information to a first node, the first information being used to determine the valid period of the first PRACH resource of the target cell, so that the first node initiates random access to the target cell using the first PRACH resource within the valid period of the first PRACH resource.

[0007] Fourthly, a method for a second node in wireless communication is provided, comprising: receiving fourth information from a target cell, the fourth information including first PRACH resource information and second PRACH resource information of the target cell and an effective time period of the first PRACH resource, wherein the first PRACH resource information is a temporary PRACH resource and the second PRACH resource information is a regular PRACH resource;

[0008] The first node sends second information, which includes information on the first PRACH resource and the second PRACH resource of the target cell; the second information includes first indication information, which is used to determine the effective time period of the first PRACH resource of the target cell; so that the first node can determine the target PRACH resource from the first PRACH resource and the second PRACH resource, and initiate random access to the target cell through the target PRACH resource.

[0009] Fifthly, a first node for wireless communication is provided, comprising a transceiver, a memory, and a processor, wherein the memory stores a program, the processor invokes the program in the memory, and controls the transceiver to receive or transmit signals, so that the first node performs the method as described in either the first or second aspect.

[0010] In a sixth aspect, a second node for wireless communication is provided, comprising a transceiver, a memory, and a processor, wherein the memory stores a program, the processor invokes the program in the memory, and controls the transceiver to receive or transmit signals, thereby causing the second node to perform the method as described in any of the implementations of the third or fourth aspects.

[0011] In a seventh aspect, embodiments of this application provide a communication system including the aforementioned first node and / or second node. In another possible design, the system may further include other devices that interact with the first node or second node as described in the embodiments of this application.

[0012] Eighthly, embodiments of this application provide a computer-readable storage medium storing a computer program that causes a computer to perform some or all of the steps in the methods described above.

[0013] Ninthly, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of the methods described in the foregoing aspects. In some implementations, the computer program product may be a software installation package.

[0014] In a tenth aspect, embodiments of this application provide a computer program operable to cause a computer to perform some or all of the steps in the methods described above.

[0015] In one aspect, embodiments of this application provide a chip including a memory and a processor, the processor being able to call and run a computer program from the memory to implement some or all of the steps described in the methods of the foregoing aspects.

[0016] In this embodiment, the terminal device can switch to the target cell through temporary PRACH resources, thereby reducing the load on the target cell's regular PRACH resources, increasing the utilization rate of the target cell's temporary PRACH resources, making full use of temporary PRACH resources, and reducing the probability of collisions on regular PRACH resources. Attached Figure Description

[0017] Figure 1 shows the wireless communication system used in an embodiment of this application.

[0018] Figure 2 is a schematic diagram of the network architecture used in the embodiments of this application.

[0019] Figures 3A and 3B are schematic diagrams of the structure of the wireless protocol stack used in the embodiments of this application.

[0020] Figure 4 is a flowchart illustrating a method used in a node for wireless communication according to an embodiment of this application.

[0021] Figure 5 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0022] Figure 6 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0023] Figure 7 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0024] Figure 8 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0025] Figures 9 to 11 are schematic diagrams of the method flow of the embodiment corresponding to Figure 8.

[0026] Figure 12 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0027] Figures 13 and 14 are schematic diagrams of the method flow of the embodiment corresponding to Figure 12.

[0028] Figure 15 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application.

[0029] Figure 16 is a schematic diagram of the structure of a node used for wireless communication according to an embodiment of this application.

[0030] Figure 17 is a schematic diagram of the structure of a node used for wireless communication according to another embodiment of this application.

[0031] Figure 18 is a schematic structural diagram of the device provided in an embodiment of this application.

[0032] Figure 19 is a schematic diagram of the hardware module of the communication device provided in the embodiment of this application. Detailed Implementation

[0033] Communication system architecture

[0034] The wireless communication system of this application embodiment may include a network device and a terminal device. The network device may be a device that communicates with the terminal device. The network device may provide communication coverage for a specific geographical area and may communicate with terminal devices located within that coverage area.

[0035] Figure 1 exemplarily illustrates a wireless communication system 100 including a network device 110 and multiple terminal devices, such as terminal devices 120a to 120j in the figure. Optionally, the wireless communication system 100 may include multiple network devices, and each network device may include other numbers of terminal devices within its coverage area; this application embodiment does not limit this.

[0036] Optionally, the wireless communication system may also include other network entities such as a network controller and a mobility management entity, which is not limited in this application embodiment.

[0037] It should be understood that the technical solutions of the embodiments of this application can be applied to various communication systems, such as: 5th-generation (5G) systems or new radio (NR) systems, long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, advanced long-term evolution (LTE-A) systems, enhanced 5G (5G advanced) systems, etc. The technical solutions provided in this application can also be applied to future communication systems, such as 6th-generation (6G) mobile communication systems, satellite communication systems, etc.

[0038] The terminal device in this application embodiment can also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal device in this application embodiment can be a device that provides voice and / or data connectivity to a user, and can be used to connect people, objects, and machines, such as a handheld device with wireless connectivity, vehicle-mounted device, etc. The terminal device in the embodiments of this application may be a mobile phone, tablet computer, laptop computer, handheld computer, camera equipment, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. Optionally, the terminal device may be used to act as a base station. For example, the terminal device may act as a scheduling entity, providing sidelink signals between UEs in vehicle-to-everything (V2X) or device-to-device (D2D) connections. For example, cellular phones and cars communicate with each other using sidelink signals. Cellular phones and smart home devices can communicate without relaying communication signals through base stations.

[0039] The network device in this application embodiment can be a device for communicating with terminal devices. This network device can also be called an access network device or a radio access network device, such as a base station (BS). In this application embodiment, the network device can refer to a radio access network (RAN) node or a next-generation RAN (NG-RAN) node (or device) that connects user equipment to a wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, transmitting and receiving point (TRP), transmitting point (TP), master station (MeNB), secondary station (SeNB), multi-mode radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, transmitting and receiving node, donor node, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and machine-to-machine (M2M) communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. Base stations can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0040] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0041] In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

[0042] Network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0043] It should be understood that all or part of the functions of the communication device in this application can also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (e.g., a cloud platform).

[0044] Figure 2 illustrates a schematic diagram of a network architecture 200 according to an embodiment of this application. This network architecture 200 describes the network architecture of a 5G NR / LTE / LTE-A system, which can also be referred to as a 5G system (5GS) / evolved packet system (EPS) network architecture. The network architecture 200 includes at least one of the following: network device 110, terminal device 120, 5G core network (5GC) / evolved packet core (EPC) 210, home subscriber server (HSS) / unified data management (UDM) 220, and Internet service 230. The network device and terminal device in Figure 2 are illustrated using RAN and UE as examples, respectively.

[0045] As shown in Figure 2, network device 110 provides user plane and control plane protocol termination to terminal device 120. Network device 110 is connected to 5GC / EPC 210 via an S1 / NG interface. 5GC / EPC 210 includes a mobility management entity (MME) / authentication management field (AMF) / session management function (SMF) 211, other MMEs / AMFs / SMFs 214, a service gateway (S-GW) / user plane function (UPF) 212, and a packet data network gateway (P-GW) / UPF 213. MME / AMF / SMF 211 is the control node that handles signaling between terminal device 120 and 5GC / EPC 210. Generally, MME / AMF / SMF 211 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the S-GW / UPF212, which is itself connected to the P-GW / UPF213. The P-GW provides UE IP address allocation and other functions. The P-GW / UPF213 is connected to Internet service 230. Internet service 230 includes operator-compliant Internet Protocol services, specifically including the Internet, intranet, IP multimedia subsystem (IMS), and packet-switched streaming services. It is evident that network architecture 200 provides packet-switched services; however, those skilled in the art will readily understand that the various concepts presented herein can be extended to networks providing circuit-switched services or other cellular networks.

[0046] Figures 3A and 3B respectively illustrate a schematic diagram of a wireless protocol stack structure according to an embodiment of this application. Figures 3A and 3B use a 5G wireless protocol stack as an example for illustration. The 5G wireless protocol stack is divided into two planes: the user plane (UP) protocol stack and the control plane (CP) protocol stack. The user plane protocol stack is the protocol suite used for user data transmission, and the control plane protocol stack is the protocol suite used for control signaling transmission in the 5G system. The specific names of each protocol stack layer are as follows:

[0047] As shown in Figure 3A, the user plane protocol stack includes, from top to bottom, the following layers: Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer.

[0048] As shown in Figure 3B, the control plane protocol stack includes, from top to bottom: non-access stratum (NAS); radio resource control (RRC) layer, PDCP layer, RLC layer, MAC layer, and PHY layer.

[0049] It should be understood that the different layers in the above protocol stack have different functions, and they work together through inter-layer interaction to achieve communication between terminal devices and network devices. With the development of artificial intelligence technology, AI-assisted computing has permeated the processing implementation methods of the above protocol stack. For example, the scheduling algorithm of the MAC layer and the encoding / decoding algorithm of the PHY layer can apply artificial intelligence algorithms to improve the performance of communication algorithms.

[0050] As an example, the wireless protocol architecture in Figures 3A and 3B is applicable to the first node in this application.

[0051] As an example, the wireless protocol architecture in Figures 3A and 3B is applicable to the second node in this application.

[0052] It should be understood that some functionalities in a wireless protocol architecture can also be implemented in one or more devices. For example, the functions of different layers in the control plane protocol stack can be implemented by multiple nodes on the network side.

[0053] It should be understood that the interpretation of the terminology in the embodiments of this application may refer to the TS36, TS37 and TS38 series of specifications of the 3rd generation partnership project (3GPP), but may also refer to the specifications of the Institute of Electrical and Electronics Engineers (IEEE).

[0054] To facilitate understanding, some related technical knowledge involved in the embodiments of this application is first introduced. The following related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0055] Triggering of the random access procedure

[0056] Random access procedures are one of the fundamental procedures in communication systems. They ensure that user equipment can quickly connect to network devices (such as base stations) when entering a cell or needing to reconnect to a cell.

[0057] Random access procedures can include various types; for example, they can include contention-based and non-contention-based random access procedures. Alternatively, random access procedures can include four-step and two-step random access procedures.

[0058] There are several ways to trigger a random access procedure. For example, it can be triggered by a physical downlink control channel (PDCCH) order, a medium access control (MAC) entity, or a radio resource control (RRC) event.

[0059] PDCCHorder triggering is mainly used when uplink synchronization fails and the network device needs to send downlink data. PDCCHorder can be used to force the user equipment to initiate a random access procedure to complete uplink time synchronization. Alternatively, PDCCHorder triggering can be used to establish time alignment for secondary timing advance groups (STAGs).

[0060] In some embodiments, the random access procedure triggered by the PDCCHorder may include two types: a contention-based random access procedure triggered by the PDCCHorder, and a contention-free random access procedure triggered by the PDCCHorder. For example, the random access procedure on the primary and secondary cells may be a contention-based random access procedure triggered by the PDCCHorder. Alternatively, the random access procedure on the secondary cell may be a contention-free random access procedure triggered by the PDCCHorder. This will be described below with reference to Tables 1 and 2.

[0061] Table 1

[0062] Table 1 shows the information the network instructs to the terminal equipment via DCI format 1_0 in the case of a contention-based random access procedure triggered by a PDCCH order. As can be seen from Table 1, when a contention-based random access procedure is triggered by a PDCCH order, DCI format 1_0 does not specify any random access resources (e.g., random access preamble, ROG, etc.), and the user equipment randomly selects a random access resource. In this case, it is easy for the random access procedure to conflict with other uplink transmissions.

[0063] As an example, the cyclic redundancy check (CRC) in this DCI format 1_0 is scrambled. For example, the CRC in this DCI format 1_0 is scrambled with the cell radio network temporary identifier (C-RNTI).

[0064] Table 2

[0065] Table 2 shows the information indicated by the network to the terminal device via DCI format 1_0 in the case of a contention-free random access procedure triggered by a PDCCH order. As can be seen from Table 2, when a contention-free random access procedure is triggered by a PDCCH order, DCI format 1_0 can only specify the RO associated with a specific SS / PBCH block. In some cases, PRACH transmission based on this RO may also lead to conflicts with other uplink transmissions.

[0066] As an example, the CRC in this DCI format 1_0 is scrambled, for example, by C-RNTI scrambling.

[0067] As an example, when the PDCCHorder triggers a contention-free random access procedure, the PRACH mask indication field in DCI format 1_0 can only be associated with a specific RO of a certain SS / PBCH block. Table 3 below provides an example of the correspondence between the PRACH mask indication field in DCI format 1_0 and the RO associated with a certain SS / PBCH block.

[0068] Table 3

[0069] As shown in the example in Table 3, there is a correspondence between the PRACH mask indicator field and the ROs associated with a certain SS / PBCH block. Therefore, when a user equipment receives DCI format 1_0, it can determine the corresponding RO based on the value indicated by the PRACH mask indicator field in DCI format 1_0. For example, if the user equipment receives a value of 0 in the PRACH mask indicator field of DCI format 1_0, it can determine that all ROs can be used for PRACH transmission. Or, if the user equipment receives a value of 3 in the PRACH mask indicator field of DCI format 1_0, it can determine that the RO corresponding to RO index 3 can be used for PRACH transmission.

[0070] In NR systems, the random access procedure allows terminal devices to initiate connection requests to network devices upon initial power-on or recovery from sleep mode. When a terminal device needs to switch to a new cell, it establishes a connection with the target cell through the random access procedure. Through the random access procedure, the terminal device can request resources from the network device for data transmission or other communication. When traffic changes, the terminal device can dynamically request the necessary resources via PRACH, enhancing network flexibility. Terminal devices can effectively reduce the probability of collisions by using random preambles and handle collisions through retransmission mechanisms.

[0071] Events that trigger a random access procedure may include, for example, initial access from a radio resource control (RRC) idle (RRC_IDLE) state, an RRC connection reconstruction process, a scheduling request (SR) failure, or beam failure recovery. Therefore, the random access procedure may be executed when the terminal device is in an RRC idle state, an RRC active (RRC_INACTIVE) state, or an RRC connected (RRC_CONNECTED) state.

[0072] To enable terminal devices in the network to perform random access, network devices need to configure PRACH resources for the terminal devices to receive random access preambles from them. As an example, the terminal device can obtain the PRACH configuration through higher-layer signaling, thereby acquiring the PRACH resources in the time domain. Each PRACH configuration has a corresponding index, and each PRACH configuration corresponds to a distribution of random access occasions (ROs). The RO distribution is typically defined by the radio frame index, the intra-frame subframe number, and the start symbol within the time slot.

[0073] During random access, the terminal device first listens to system information sent by the network device, such as system information blocks (SIBs) 1 and 2, to understand the configuration and availability of PRACH resources. Then, based on the obtained PRACH configuration, the terminal device selects a PRACH preamble for random access. The terminal device sends the random access preamble within a predetermined PRACH time slot, and the network device processes the received preamble.

[0074] As an example, as shown in Figure 4, the handover process for a terminal device to switch to a new cell includes the following steps: S400, the UE's source cell notifies the UE to perform measurement configuration. S410, the UE continuously performs Radio Resource Management (RRM) measurements, monitoring the signal quality (e.g., RSRP, RSRQ) of the current serving cell (source cell) and neighboring cells (cell 1, cell 2), and the UE performs simulated signal strength measurements on cell 1, finding that its measurement upper limit is optimal (e.g., highest signal strength, lowest interference), and determines cell 1 as the best handover target. S420, the UE reports the measurement results to the current serving cell (source cell). S430, the source cell sends a handover request to the network side (e.g., base station) of cell 1, requesting to switch from the current serving cell to cell 1. S440, cell 1 sends a handover request response to the source cell. S450, the source cell sends a handover command to the UE via an RRC message, notifying the UE to perform the handover. S460, the UE sends a random access preamble to cell 1, requesting access resources. S470: After receiving the preamble, Cell 1 allocates uplink resources and sends a Random Access Response (RAR) to notify the UE that it can continue accessing the network. S480: After the UE successfully accesses Cell 1, it sends a "handover complete" message to the network, the source cell releases the connection, and the handover process ends.

[0075] The handover command in Figure 4 includes the PRACH configuration parameters of the target cell (e.g., cell 1) and the dedicated random access preamble indication, so the number of bits in the message carrying the handover command is relatively large. After receiving the handover command, the UE initiates random access (RA) to the target cell (e.g., cell 1), obtains the uplink synchronization time advance (TA) value and uplink radio resources, and sends a "handover complete" message to the target cell (e.g., cell 1) through the uplink radio resources allocated by the target cell (e.g., cell 1), thereby handing over to the target cell (e.g., cell 1).

[0076] In the handover process shown in Figure 4, the handover command message contains too many bits, and the radio conditions between the source cell and the UE are usually poor when the handover occurs. Therefore, the handover message may not be transmitted to the UE in time, leading to handover failure. This situation can be avoided if the network sends the handover command in advance, that is, when the radio conditions between the source cell and the UE are not too bad. However, after the UE receives the handover command, it immediately establishes a connection with the target cell. At this time, the radio conditions between the target cell and the UE are still poor, which will lead to failure to successfully access the target cell.

[0077] To address this issue, Layer 1 or Layer 2-triggered mobility (LTM) is introduced. The handover process shown in Figure 5 includes the following steps: S500, the UE's source cell notifies the UE to perform measurement configuration. S510, the UE continuously monitors the signal quality (e.g., RSRP, RSRQ) of the current serving cell (source cell) and multiple neighboring cells (e.g., cell 1, cell 2, ..., cell n), and performs simulated signal strength measurements on multiple neighboring cells, selecting cell 1 and cell 2 as candidate cells for LTM. S520, the UE reports the measurement results to the current serving cell (source cell). S530, the source cell and candidate cells (e.g., cell 1, cell 2) negotiate handover (e.g., resource reservation, interference coordination) to confirm handover feasibility. S540, the source cell sends the candidate cell configuration to the UE. S550, based on the physical layer (L1) real-time measurement results, the UE confirms that cell 1 has the best signal quality and sends the L1 measurement results to the source cell. S560, the source cell uses an LTM command to specify that the UE should hand over to cell 1. S570, the UE sends a preamble to cell 1, requesting access resources. S580, after receiving the preamble, cell 1 allocates uplink resources and sends a random access response (RAR) to notify the UE that it can continue accessing the network. S590, after successfully accessing cell 1, the UE sends a "handover complete" message to the network, the source cell releases the connection, and the handover process ends.

[0078] In the LTM procedure, the terminal device can perform L1 measurements on candidate cells that it may switch to and report the measurement results to the network device corresponding to the serving cell. The network device corresponding to the serving cell can determine whether to trigger LTM handover based on the L1 measurement results and determine whether the terminal device can access the target cell through a no-random access procedure. As shown in Figure 5, the source cell pre-notifies the UE of the configuration parameters of several candidate cells, including PRACH configuration parameters. When the radio conditions meet the handover requirements, the source cell notifies the UE to access the target cell via LTM signaling. Since the LTM signaling does not contain the configuration parameters of the target cell, the message is relatively small, greatly increasing the probability of successful transmission to the UE, thus solving the handover failure problem. The scheme shown in Figure 5 solves the problem of difficult handover command transmission, but its drawback is excessive handover latency.

[0079] To further reduce handover latency, a "pre-uplink synchronization" mechanism is introduced based on the process shown in Figure 5. Before the handover occurs, the base station triggers the UE to initiate random access to one or more candidate cells to obtain uplink synchronization advance time. This eliminates the need for random access during the handover process, thus reducing handover latency. In the LTM command, the base station notifies the UE of the target cell ID and the TA used by the UE in the target cell. After receiving the LTM command, the UE directly transmits data with the target cell. Specifically, it directly transmits uplink data to the target cell through CG resources or listens to downlink data sent by the target cell, responding with ACK / NACK, and then the handover is completed. As shown in Figure 6, the process includes the following steps: S600, the UE's source cell notifies the UE to perform measurement configuration. S601, the UE continuously performs RRM measurements, monitoring the signal quality (e.g., RSRP, RSRQ) of the current serving cell (source cell) and multiple neighboring cells (e.g., cell 1, cell 2, ..., cell n), and the UE performs simulated signal strength measurements on multiple neighboring cells, selecting cell 1 and cell 2 as candidate cells for LTM. S602, the UE reports the measurement results to the current serving cell (source cell). S603, the source cell negotiates handover with candidate cells (e.g., cell 1, cell 2) (e.g., resource reservation, interference coordination) to confirm handover feasibility. S604, the source cell sends the candidate cell configuration to the UE. S605, the source cell sends a PDCCH order to the UE, which triggers the UE to send a random access preamble to cell 1. S606, the UE sends a random access preamble to cell 1. S607, cell 1 measures the uplink transmission time advance TA_1 based on the received random access preamble and notifies the source cell of TA_1. S608, the source cell sends another PDCCH order to the UE, which triggers the UE to send a random access preamble to cell 2. S609, the UE sends a random access preamble to cell 2. S610, cell 2 measures the uplink transmission time advance TA_2 based on the received random access preamble and notifies the source cell of TA_2. S611, the UE confirms that cell 1 has the best signal quality based on the real-time physical layer (L1) measurement results and sends the L1 measurement results to the source cell. S612, the source cell uses the LTM command to instruct the UE to hand over to cell 1. S613, the UE uses TA_1 to transmit data with cell 1.

[0080] In Figure 6, the source cell identifies Cell 1 and Cell 2 as candidate cells. During the "Candidate Cell Configuration" step, it notifies the UE of the random access resource parameters for Cell 1 and Cell 2. Subsequently, the source cell triggers the UE to send random access preambles to Cell 1 and Cell 2 respectively via two PDCCH orders. Cell 1 measures the uplink transmission time advance TA_1 based on the received random access preamble and notifies the source cell of TA_1; Cell 2 measures the uplink transmission time advance TA_2 based on the received random access preamble and notifies the source cell of TA_2. When the source cell receives the L1 measurement results reported by the UE, it determines that the UE is switching to Cell 1 and notifies the UE to switch to Cell 1 via an LTM command, while simultaneously notifying the UE of the value of TA_1. The UE uses TA_1 to transmit data with Cell 1. The validity of TA_1 and TA_2 is guaranteed by the source cell. If the source cell considers TA_1 / TA_2 to be invalid, it triggers the UE to send a preamble again via a PDCCH order.

[0081] Due to the high power consumption of 5G networks, to save network power, PRACH resources are divided into two categories: existing periodic PRACH resources and temporarily configured PRACH resources. When the network side determines that a large number of UEs need to initiate random access, it notifies the UE that the temporarily configured PRACH resources are in effect. In one possible scenario, if the target cell uses temporary PRACH resources and notifies the UE of the temporary PRACH resources and dedicated random access preamble, if the UE fails to access the target cell, it will attempt random access a second time until it succeeds or reaches the maximum number of random access attempts. If the temporary PRACH resources of the target cell are still valid during the UE's random access attempt, the UE will successfully access the target cell through the temporary PRACH resources; if the temporary PRACH resources of the target cell are no longer valid during the UE's random access attempt, the UE may send preambles on non-PRACH resources, thereby interfering with the uplink transmission of other UEs. For example, as shown in Figure 7, the following steps are included: S700, the UE's source cell notifies the UE to perform measurement configuration. S710, the UE performs RRM measurements, continuously monitoring the signal quality (e.g., RSRP, RSRQ) of the current serving cell (source cell) and neighboring cells (cell 1, cell 2), and performs simulated signal strength measurements on cell 1, finding it to have the optimal measurement upper limit (e.g., highest signal strength, lowest interference), and determines cell 1 as the best handover target. S720, the UE reports the measurement results to the current serving cell (source cell). S730, the source cell sends a handover request to the network side (e.g., base station) of cell 1, requesting a handover from the current serving cell to cell 1. S740, cell 1 sends a handover request response to the source cell, which includes cell 1's temporary PRACH resource information. S750, the source cell sends a handover command to the UE via an RRC message, notifying the UE to perform the handover; this handover command includes cell 1's temporary PRACH resource information. S760, the UE attempts random access for the first time, sending a random access preamble to cell 1 to request access resources. S770: The UE's first RA failure occurs. At this time, the temporary PRACH resource is still valid. The UE attempts random access a second time, sending a random access preamble to cell 1 again to request access resources. S780: The UE's second RA failure occurs. This time, the temporary PRACH resource is no longer valid, but the UE is unaware that the PRACH resource is temporary. The source cell, however, knows that the PRACH resource in cell 1 is temporary, and the UE is unaware of the temporary PRACH resource's validity period. It assumes this PRACH resource is regular, i.e., periodically occurring, and will attempt to access the PRACH resource corresponding to the next period as it perceives it to be. However, the temporary PRACH resource has already expired, and the radio resource for the next period is a non-PRACH resource, thus interfering with the data transmission of other UEs.

[0082] To address the aforementioned issues, this application provides a method and apparatus for use in nodes for wireless communication. During a terminal device's attempt to access the network, the network side indicates the effective period of the temporary PRACH resource of the target cell to the terminal device, so that the terminal device can determine whether to use the temporary PRACH resource to complete the cell handover.

[0083] This application can be applied to scenarios involving multiple PRACH transmissions, meaning that multiple PRACH transmissions can be repeated to achieve PRACH coverage enhancement.

[0084] This application can be applied to various random access procedures. As one embodiment, this application can be applied to a four-step random access procedure. As another embodiment, this application can be applied to a two-step random access procedure. As one embodiment, this application can be applied to a contention-based random access procedure. As yet another embodiment, this application can be applied to a non-contention-based random access procedure.

[0085] This application can be applied to random access procedures triggered by different triggering methods. As one embodiment, this application can be applied to a random access procedure triggered by a PDCCH order. As another embodiment, this application can be applied to a random access procedure triggered by a MAC entity or a random access procedure triggered by handover conditions. As yet another embodiment, this application can be applied to a random access procedure triggered by an RRC event.

[0086] As an example, the multiple PRACH transmissions mentioned in this application may refer to multiple PRACH transmissions using the same beam, so as to obtain signal-to-noise ratio (SNR) gain by repeating multiple PRACH transmissions on the same beam.

[0087] As an example, the multiple PRACH transmissions mentioned in this application may refer to multiple PRACH transmissions using different beams, in order to obtain diversity gain by repeatedly transmitting multiple PRACHs on different beams.

[0088] The methods and apparatus provided in this application are illustrated below through multiple embodiments or examples. It should be understood that, unless otherwise specified, the embodiments and features in the first node of this application can be applied to the second node, and vice versa. Unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0089] Figure 8 is a flowchart illustrating a method used in a node for wireless communication according to an embodiment of this application. The method shown in Figure 8 can be executed by a first node. A brief introduction to the first node follows.

[0090] As an example, the first node may be a user equipment, for example, the first node may be a device among user equipment 120i to terminal equipment 120j shown in FIG1.

[0091] As an example, the first node can be a network-controlled repeater (NCR).

[0092] As an example, the first node can be a relay, such as a relay terminal.

[0093] As an example, the second node can be a base station.

[0094] As an example, the second node can be a network control relay.

[0095] As an example, the second node can be a relay, such as a relay terminal.

[0096] The method shown in Figure 8 will be described below. Referring to Figure 8, the method shown in Figure 8 may include steps S810 and S820.

[0097] In S810, the first node receives the first information.

[0098] As one embodiment, the first information is a first timer. The first timer in the switching command or LTM command is used to determine whether the first PRACH resource configured for the first node is valid. The first timer times out before the first PRACH resource expires.

[0099] As one embodiment, the first information can be configured by the second node through system messages and / or higher-level parameters. That is, the first PRACH resource can be indicated using existing protocol methods, with the addition of configuration information for the effective time period. For example, in the system message, the configuration of the first PRACH resource is achieved through at least one of the following parameters: preamble format, time-domain configuration, and frequency-domain configuration. After powering on, the UE scans the synchronization signal (PSS / SSS) and decodes the MIB to obtain basic parameters (such as system bandwidth). The PRACH configuration table (RACH-ConfigCommon) is obtained through SIB1.

[0100] In S820, during the valid period of the first PRACH resource, the first node uses the first PRACH resource to initiate random access to the target cell.

[0101] Optionally, outside the valid period of the first PRACH resource, the first PRACH resource is no longer used to initiate random access to the target cell, or a regular PRACH resource is used. For example, when the first timer expires, the first node considers the handover to have failed and no longer uses the first PRACH resource to initiate random access to the target cell. It should be understood that unless specifically indicated, the first node (e.g., the UE) is unaware that the PRACH resource is temporary, while the second node (e.g., the source cell) is aware that the target cell's PRACH resource is temporary.

[0102] As an example, the duration of the first timer is determined based on the valid time period of the first PRACH resource. When the first timer expires, the first PRACH resource will either expire or expire simultaneously.

[0103] In one possible embodiment, the first information is also used to indicate that the first PRACH resource is a temporary PRACH resource.

[0104] The above method will be described in detail below with reference to several specific embodiments.

[0105] Figure 9 is a flowchart illustrating a method used in a node for wireless communication according to an embodiment of this application. The method shown in Figure 9 is described from the perspective of interaction between the UE and the cell.

[0106] The method flow shown in Figure 9 is described below. Referring to Figure 9, the method shown in Figure 9 may include S910 to S960.

[0107] S900, the UE's source cell notifies the UE to perform measurement configuration.

[0108] S910, the UE performs RRM measurement, continuously monitors the signal quality (such as RSRP, RSRQ) of the current serving cell (source cell) and neighboring cells (cell 1, cell 2), and performs signal strength simulation measurement on cell 1. It finds that its measurement upper limit is optimal (such as the highest signal strength and the least interference), and determines cell 1 as the best handover target.

[0109] S920, the UE reports the measurement results to the current serving cell (source cell).

[0110] S930, the source cell sends a handover request to the network side (such as the base station) of cell 1, requesting to switch from the current serving cell to cell 1.

[0111] Optionally, the handover request may include UE capability information, including UE support for temporary PRACH resources. This capability information notifies the target cell that "the UE supports temporary PRACH resources." The target cell (e.g., cell 1) then adds "temporary PRACH resource configuration parameters and the effective period of the temporary PRACH resources" to the information that needs to be transparently transmitted to the UE in the handover request response. These two newly added items are not visible to the source cell. After being transparently transmitted to the UE, the UE can use the temporary PRACH resources during the effective period when performing random access in the target cell.

[0112] In one possible implementation, the effective time period of the temporary PRACH resource can be represented based on the SFN of the target cell. For example, the temporary PRACH resource is valid within the interval from SFN=502 to SFN=602, and is no longer valid in other time periods. Upon receiving the request, the UE considers that "from the time the handover command is received, the next SFN=502 is the start of the effective time period of the temporary PRACH, and the next SFN=602 is the end of the effective time period of the temporary PRACH." It is worth noting that the effective time period of the temporary PRACH resource can be represented as a single continuous time period or as multiple consecutive time periods.

[0113] S940, Cell 1 sends a handover request response to the source cell. The response includes the temporary PRACH resource information of Cell 1 and the valid time period of the temporary PRACH resource.

[0114] In other words, when the target cell receives a handover request message, it determines whether the current temporary PRACH resource is valid or whether the temporary PRACH resource will take effect immediately, and then notifies the source cell through a handover request response. The temporary PRACH resource information of cell 1 and the validity period of the temporary PRACH resource in this handover request response are also referred to as third information.

[0115] S950, the source cell sends a handover command to the UE via an RRC message. This handover command is used to notify the UE to perform a handover. The handover command includes temporary PRACH resource information for cell 1 and first information. The first information is used to determine the valid time period of the temporary PRACH resource for cell 1.

[0116] As one possible implementation, the first information can be a first timer. The duration of the first timer is determined based on the effective period of the temporary PRACH resource of cell 1. When the first timer expires, the temporary PRACH resource of cell 1 will expire. In other words, the first timer expires first, and the temporary PRACH resource expires later.

[0117] For example, the first timer is the reconfigured timer T304. The source cell can reconfigure the value of T304 based on the temporary PRACH resources of the target cell. When the target cell sends a handover request response to the source cell, it directly includes the "reconfigured timer T304" information in the handover command and transmits it to the UE through the source cell. From the source cell's perspective, it is unaware that the target cell is notifying the UE that it is using temporary PRACH resources, nor is it aware that the target cell has reconfigured timer T304. From the UE's perspective, it is unaware that the regular PRACH resources allocated by the target cell are temporary PRACH resources; it only knows that timer T304 is being used. If timer T304 times out, the UE considers the handover to have failed and will no longer initiate random access to the target cell.

[0118] As another example, the first timer can be a newly defined timer. The function of the newly defined timer is similar to that of timer T304, both used to control the effective duration for which the UE uses the target cell's PRACH resources.

[0119] S960: The UE shall attempt to access the target cell randomly at least once during the valid period of the temporary PRACH resource. If the timeout occurs, the random access is considered to have failed and the UE shall no longer attempt to access the target cell randomly.

[0120] In S960, referring to Figure 9, for example, the UE attempts random access for the first time by sending a random access preamble to cell 1 to request access resources. If the UE's first RA fails, the temporary PRACH resource is still valid. The UE then attempts random access a second time, again sending a random access preamble to cell 1 to request access resources. If the UE's second RA fails, the temporary PRACH resource is no longer valid, and the UE considers the random access attempt to have failed and will no longer initiate random access to the target cell, thus avoiding interference with data transmission for other UEs.

[0121] As another possible implementation, the aforementioned first information could be indication information used to indicate the effective period of the temporary PRACH resources in the target cell. That is, when the target cell sends a handover request response to the source cell, it no longer includes the "T304 reconfiguration" information in the handover command. Instead, it explicitly notifies the source cell of the "effective period of the PRACH resources" or "please reconfigure T304," or "please reconfigure T304, the reason for reconfiguration is temporary PRACH resources," through the indication information. After receiving the handover request response, the source cell reconfigures T304 for the UE or defines a new timer based on the effective period of the PRACH resources in the target cell, and then sends a handover command to the UE including the aforementioned timer. Alternatively, after receiving the handover request response, the source cell sends this indication information to the UE; this indication information can be carried in the handover command or sent separately.

[0122] As one possible implementation, the effective period of the PRACH resources notified by the target cell to the source cell can be a specific duration. For example, if the effective period is 2 seconds, the source cell, upon receiving the handover request response, considers the target cell's PRACH resources valid for 2 seconds, and can then reconfigure T304 for 2 seconds. In another possible implementation, the effective period can also be a start and / or end time. For example: starting now, at the Xth time when SFN = 546, the PRACH resources expire, where X is a natural number. The source cell determines the reconfigured T304 value based on its known SFN information for the target cell.

[0123] Optionally, the target cell may notify the source cell of the following information in the "Handover Request Response": expecting the UE to use temporary PRACH resources to handover to the target cell.

[0124] Optionally, the target cell may also notify neighboring cells when the base station is powered on and the inter-cell interface is established that "when the UE hands over, it is hoped that the UE will use temporary PRACH resources to hand over to the cell".

[0125] Through the above processing, the UE can use the temporary PRACH resources of the target cell to complete the cell handover, which helps to reduce random access latency, improve the utilization efficiency of random access resources, and reduce the occupation of the regular PRACH resources of the target cell. As a result, the target cell can be configured with relatively sparse regular PRACH resources, thereby saving network power consumption.

[0126] Figure 10 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application. The method shown in Figure 10 is described from the perspective of interaction between the UE and the cell.

[0127] The method flow shown in Figure 10 is described below. Referring to Figure 10, the method shown in Figure 10 may include S1000 to S1092.

[0128] S1000 to S1050 are similar to S500 to S550 in Figure 6. The difference between S1040 and S540 is that when the source cell provides the "alternate cell configuration" to the UE, it notifies the UE of the temporary PRACH resource information of the alternative cell.

[0129] S1060, the source cell specifies that the UE should hand over to cell 1 via an LTM command. This LTM command includes information related to cell 1, as well as the PRACH configuration for cell 1.

[0130] In one possible embodiment, the PRACH configuration includes temporary PRACH resource information for cell 1.

[0131] In another possible embodiment, to reduce the size of the LTM command, detailed configuration information of the temporary PRACH resources can be notified to the UE via S1040 when configuring the candidate cell in the source cell. For example, one or more sets of temporary PRACH resources can be configured. These multiple sets of temporary PRACH resources can differ in time dimension or frequency domain dimension, and are represented by different index numbers. When the corresponding temporary PRACH needs to be notified in the LTM command, the index corresponding to the temporary PRACH can be notified via the LTM command.

[0132] S1070, after the source cell sends an LTM command to the UE, the UE uses the temporary PRACH resources of cell 1 to initiate random access to cell 1.

[0133] S1080, if the temporary PRACH resource fails, the source cell can reissue the "alternate cell configuration" to the UE to notify the UE of the PRACH configuration of the alternative cell, wherein the PRACH configuration may include the new PRACH configuration information of cell 1.

[0134] Optionally, if the alternative cell determines a new temporary PRACH configuration, the "alternate cell configuration" notified by the source cell to the UE may include subsequent temporary PRACH configuration information.

[0135] Alternatively, if the candidate cell is configured with regular PRACH resources, the "candidate cell configuration" notified by the source cell to the UE may include regular PRACH configuration information for the next cycle.

[0136] S1090, after receiving the message, the UE uses the new PRACH resources of cell 1 to initiate random access by sending a random access preamble to cell 1.

[0137] S1091, after receiving the preamble, cell 1 allocates uplink resources and sends back a Random Access Response (RAR) to notify the UE that it can continue to access the network.

[0138] S1092, after the UE successfully accesses cell 1, it sends a "handover complete" message to the network, the source cell releases the connection, and the handover process ends.

[0139] In one possible embodiment, when a UE accesses a target cell (such as cell 1), it can combine two types of PRACH resources. The combination method includes one of the following:

[0140] Method A: Use a temporary PRACH first, and then use a regular PRACH after it expires;

[0141] Method B: First use the regular PRACH, then use the temporary PRACH when a temporary PRACH becomes available, and then use the regular PRACH again when the temporary PRACH expires.

[0142] The following description further illustrates the method flow shown in Figure 10 with reference to Figure 11. At time T1, the UE receives the temporary PRACH resource configuration from the target cell. At time T2, the UE receives the LTM command from the source cell. At time T3, the UE receives the regular PRACH resource configuration from the target cell. The UE begins random access at time T2; if this fails, it continues to attempt random access until time T4. During the period from T2 to T3, the UE first uses the temporary PRACH resource configuration for access. During the period from T3 to T4, the UE has the following two processing methods:

[0143] Method 1: Use the latest regular PRACH resource configuration received at time T3 instead, without needing to receive LTM again.

[0144] Method 2: Continue using the PRACH configuration received before LTM, i.e., temporary PRACH resources. If a second LTM command is received after receiving regular PRACH resource information, then the latest received regular PRACH resources will be used to continue attempting random access.

[0145] Considering that in some scenarios, the temporary PRACH resource of the target cell may no longer be valid, but T304 has not yet timed out, causing the UE to be unable to use the temporary PRACH resource to initiate random access to the target cell, in order to solve this problem, this embodiment provides a flowchart of a method used in a node for wireless communication.

[0146] Figure 12 is a flowchart illustrating a method used in a node for wireless communication according to an embodiment of this application. The method shown in Figure 12 can be executed by a first node and a second node. The first node and the second node can be referred to the description above.

[0147] The method shown in Figure 12 will be described below. Referring to Figure 12, the method shown in Figure 12 may include steps S1210 and S1220.

[0148] In S1210, the first node receives second information, which includes information on the first PRACH resource and the second PRACH resource of the target cell; the first PRACH resource is a temporary PRACH resource, and the second PRACH resource is a periodic regular PRACH resource; the second information includes first indication information, which is used to determine the effective time period of the first PRACH resource of the target cell.

[0149] In one possible implementation, the effective time period of the temporary PRACH resource can be represented based on the SFN of the target cell. For example, the temporary PRACH resource is valid within the interval from SFN=502 to SFN=602, and is no longer valid in other time periods. Upon receiving the request, the UE considers that "from the time the handover command is received, the next SFN=502 is the start of the effective time period of the temporary PRACH, and the next SFN=602 is the end of the effective time period of the temporary PRACH." It is worth noting that the effective time period of the temporary PRACH resource can be represented as a single continuous time period or as multiple consecutive time periods.

[0150] In S1220, a target PRACH resource is determined from the first PRACH resource and the second PRACH resource, and random access is initiated to the target cell through the target PRACH resource.

[0151] As one possible embodiment, the target PRACH resource satisfies at least one of the following:

[0152] The target PRACH resource is the PRACH resource that is closest to the current time among the first PRACH resource and the second PRACH resource;

[0153] The target PRACH resource is a temporary PRACH resource that is preferentially selected by the network side;

[0154] The target PRACH resource is a regular PRACH resource that is preferentially selected by the network side;

[0155] The target PRACH resource is a regular PRACH resource that is preferentially selected by the protocol.

[0156] The above method will be described in detail below with reference to specific embodiments.

[0157] Figure 13 is a flowchart illustrating a method used in a node for wireless communication according to an embodiment of this application. The method shown in Figure 13 is described from the perspective of interaction between the UE and the cell. The method shown in Figure 13 may include steps S1300 to S1390.

[0158] S1300 to S1350 are similar to S500 to S550 in Figure 6. The difference between S1340 and S540 is that the source cell provides the UE with "alternate cell configuration", thereby notifying the UE of the temporary PRACH resource information of the alternative cell.

[0159] S13060, the source cell specifies that the UE should hand over to cell 1 via an LTM command. This LTM command includes information related to cell 1, as well as the PRACH configuration for cell 1.

[0160] This PRACH configuration includes temporary PRACH resource information and regular PRACH resource information for cell 1, as well as the validity period of the temporary PRACH resources. It should be understood that regular PRACH resources are valid indefinitely.

[0161] In another possible embodiment, to reduce the size of the LTM command, detailed configuration information of the temporary PRACH resources can be notified to the UE via S1040 when configuring the candidate cell in the source cell. For example, one or more sets of temporary PRACH resources can be configured. These multiple sets of temporary PRACH resources can differ in time dimension or frequency domain dimension, and are represented by different index numbers. When the corresponding temporary PRACH needs to be notified in the LTM command, the index corresponding to the temporary PRACH can be notified via the LTM command.

[0162] S1370, the UE selects a target PRACH resource and sends a random access preamble to cell 1 through the target PRACH resource to initiate at least one random access.

[0163] S1380, after receiving the preamble, cell 1 allocates uplink resources and sends back a Random Access Response (RAR) to notify the UE that it can continue to access the network.

[0164] S1390, after the UE successfully accesses cell 1, it sends a "handover complete" message to the network, the source cell releases the connection, and the handover process ends.

[0165] As one possible implementation, the UE can select the PRACH resource with the most recent time to initiate random access to the target cell, or the network side can be configured to prioritize one type of PRACH resource, for example, temporary PRACH resources can be configured to be prioritized.

[0166] As one possible implementation, the network side can configure which type of PRACH resource the UE should prioritize, either by the target cell or by the source cell.

[0167] As one possible implementation, the target cell may also need to include regular PRACH resources, as well as temporary PRACH resources and their effective time periods, in the information that it needs to pass through to the UE during the handover request response or handover negotiation.

[0168] As one possible implementation, the network side can configure an interval duration threshold (GAP). In the example shown in Figure 14, if the UE fails to initiate random access to the target cell at time T1 and determines that it needs to initiate random access again, and if the UE determines that temporary PRACH resources are available at time T2, and the interval between the first and second times is a first duration, and both temporary and regular PRACH resources are available within the first duration, and the first duration is less than the GAP, then the UE will not use the regular PRACH resources within the first duration to initiate random access to the target cell. Instead, it will wait for temporary PRACH resources at time T2 that fall within the first duration to initiate random access again. Conversely, if the first duration is greater than the GAP, the UE will use regular PRACH resources to initiate random access.

[0169] The above improvements allow UEs to prioritize temporary PRACH resources and secondarily select regular PRACH resources, which can improve the utilization efficiency of random access resources and reduce the occupation of regular PRACH resources in the target cell. As a result, the target cell can be configured with relatively sparse regular PRACH resources, thereby saving network power consumption.

[0170] Figure 15 is a flowchart illustrating a method used in a node for wireless communication according to another embodiment of this application. The method shown in Figure 15 is described from the perspective of interaction between the UE and the cell.

[0171] The method flow shown in Figure 15 is described below. Referring to Figure 15, the method shown in Figure 15 may include S1500 to S1513.

[0172] S1500 to S1504 are the same as S601 to S604. Among them, the cell configuration fed back by cell 1 and cell 2 during the handover negotiation process is also called the fourth information. The fourth information includes the first PRACH resource information and the second PRACH resource information of the target cell, as well as the effective time period of the first PRACH resource. The first PRACH resource information is a temporary PRACH resource, and the second PRACH resource information is a periodic regular PRACH resource.

[0173] S1505, the source cell sends a PDCCH order to the UE. This PDCCH order is used to trigger the UE to send a random access preamble to cell 1.

[0174] As one possible implementation, to save power consumption of the alternative cell, the alternative cell can notify the source cell during the "handover negotiation" step that it "desires to receive the preamble from the UE as close as possible to the temporary PRACH opportunity." Once the source cell receives this instruction, it can try to send a PDCCH order to the UE close to the temporary PRACH opportunity. It should be understood that the UE does not know whether the PRACH resource is temporary or regular, while the source cell knows that the PRACH resource of cell 1 is temporary and triggers the UE to send a random access preamble to cell 1 through the PDCCH order.

[0175] S1506, the UE sends a random access preamble to cell 1 through the PRACH resources of cell 1.

[0176] Optionally, the UE can send a random access preamble to cell 1 using the temporary PRACH resources of cell 1. This allows full utilization of the temporary PRACH resources and reduces the probability of collisions on regular PRACH resources.

[0177] S1507, Cell 1 measures the uplink transmission time advance TA_1 based on the received random access preamble and notifies the source cell of TA_1.

[0178] As one possible implementation, if the target cell currently has temporary PRACH resources, and the next temporary PRACH resources will only become available after TA_1 expires, then the source cell sends a PDCCH order to the UE, triggering the UE to initiate random access to a candidate cell and obtain the latest TA_1. In this way, since the source cell has a valid TA_1 when sending LTM, the UE can access cell 1 regardless of whether cell 1 has a PRACH.

[0179] S1508, the source cell sends another PDCCH order to the UE. This PDCCH order is used to trigger the UE to send a random access preamble to cell 2.

[0180] S1509, the UE sends a random access preamble to cell 2 through the PRACH resources of cell 2.

[0181] Optionally, the UE can send a random access preamble to cell 2 using the temporary PRACH resources of cell 2. This makes full use of the temporary PRACH resources and reduces the probability of collisions on regular PRACH resources.

[0182] S1510, Cell 2 measures the uplink transmission time advance TA_2 based on the received random access preamble and notifies the source cell of TA_2.

[0183] As one possible implementation, if the target cell currently has temporary PRACH resources, and the next temporary PRACH resource will only become available after TA_2 expires, then the source cell sends a PDCCH order to the UE, triggering the UE to initiate random access to a candidate cell and obtain the latest TA_2. In this way, since the source cell has a valid TA_2 when sending LTM, the UE can access cell 2 regardless of whether cell 2 has a PRACH.

[0184] S1511, the UE confirms again that the signal quality of cell 1 is the best based on the real-time measurement results of the physical layer (L1), and sends the L1 measurement results to the source cell.

[0185] S1512, the source cell uses the LTM command to specify that the UE should switch to cell 1.

[0186] S1513, the UE uses TA_1 to transmit data with cell 1.

[0187] Optionally, in the above process, the source cell can also send "alternate cell configuration" to the UE again to modify the PRACH resources of the target cell. This is similar to the embodiment corresponding to Figure 6.

[0188] As one possible implementation, during the conditional handover procedure, the source cell notifies the UE of the TA values ​​(TA_1, TA_2, etc.) obtained for each candidate cell, and also stores these TA values. When one or more of these TA values ​​become invalid, the source cell can notify the UE to initiate a preamble with the candidate cells again and obtain TAs again. The source cell can choose to notify the UE before the temporary PRACH timing of the candidate cells, thereby guiding the UE to initiate a preamble on the temporary PRACH resources, thus saving energy consumption in the candidate cells.

[0189] Optionally, if the temporary PRACH resources of the candidate cell appear periodically, the candidate cell can periodically notify the source cell, allowing the source cell to anticipate subsequent temporary PRACH resources from the candidate cell. If the temporary PRACH resources of the candidate cell do not appear periodically, the candidate cell needs to notify the source cell before the temporary PRACH resources take effect, and the source cell decides whether to trigger the UE to resend the preamble to obtain the latest TA.

[0190] The process described in Figure 15 also applies to the LTM conditional handover introduced in R19. In Figure 15, only the source cell knows whether TA_1 and TA_2 are valid. The source cell guarantees that the TA is valid when issuing the LTM command. During LTM conditional handover, not only the source cell but also the UE knows whether TA_1 and TA_2 are valid. Thus, when the UE determines that the LTM conditions are met and the TA is valid, it will directly access the backup cell without initiating random access. If the LTM conditions are met but the TA is invalid, it will initiate random access to the backup cell. After the target cell introduces temporary PRACH resources, the source cell can guarantee that the UE always retains a valid TA, and the source cell prioritizes allowing the UE to send a preamble to the backup cell through temporary PRACH resources when sending the PDCCH order.

[0191] In the above embodiments, it is not necessary to change the message structure of the air interface; only the inter-cell interaction information and the algorithm of the source cell need to be changed to achieve the desired result. Using the method described in this invention, the UE can handover to the target cell via temporary PRACH resources, reducing the load on the target cell's regular PRACH resources, increasing the utilization rate of the target cell's temporary PRACH resources, and reducing the target cell's network power consumption.

[0192] The method embodiments of this application have been described in detail above with reference to Figures 1 to 15. The apparatus embodiments of this application will be described in detail below with reference to Figures 16 to 19. It should be understood that the descriptions of the method embodiments correspond to the descriptions of the apparatus embodiments; therefore, any parts not described in detail can be referred to the preceding method embodiments.

[0193] Figure 16 is a schematic diagram of the structure of a node used for wireless communication according to an embodiment of this application. The node 1600 shown in Figure 16 can be any of the first nodes described above. The node 1600 may include a first transceiver unit 1610 and a first processing unit 1620.

[0194] The first transceiver unit 1610 can be used to receive first information, which is used to determine the effective time period of the first PRACH resource of the target cell.

[0195] The first processing unit 1620 can be used to initiate random access to the target cell using the first PRACH resource during the effective period of the first PRACH resource.

[0196] As an example, outside the valid period of the first PRACH resource, the first processing unit 1620 no longer uses the first PRACH resource to initiate random access to the target cell.

[0197] As an example, the first information is a first timer. The duration of the first timer is determined based on the effective period of the first PRACH resource. When the first timer expires, the first PRACH resource will expire or expire simultaneously.

[0198] As an example, the first information is carried in a switching command or an LTM command.

[0199] As an example, the first PRACH resource is a regular PRACH resource or a temporary PRACH resource.

[0200] As an example, the first information is also used to indicate that the first PRACH resource is a temporary PRACH resource.

[0201] As an example, the handover command or LTM command may further include: information on the second PRACH resource of the target cell configured for the first node.

[0202] As an example, outside the valid period of the first PRACH resource, the first processing unit 1620 uses the second PRACH resource to initiate random access to the target cell.

[0203] As one embodiment, the first transceiver unit 1610 can be used to receive second information, the second information including first PRACH resource information and second PRACH resource information of the target cell; the first PRACH resource information is a temporary PRACH resource, and the second PRACH resource information is a regular PRACH resource; the second information includes first indication information, the first indication information being used to determine the effective time period of the first PRACH resource of the target cell; the first processing unit 1620 is used to determine the target PRACH resource from the first PRACH resource and the second PRACH resource, and initiate random access to the target cell through the target PRACH resource.

[0204] As an example, the target PRACH resource satisfies at least one of the following:

[0205] The target PRACH resource is the PRACH resource that is closest to the current time among the first PRACH resource and the second PRACH resource;

[0206] The target PRACH resource is a temporary PRACH resource that is preferentially selected by the network side;

[0207] The target PRACH resource is a regular PRACH resource that is preferentially selected by the network side.

[0208] As one embodiment, the first processing unit 1620 is further configured to:

[0209] When the first attempt to initiate random access to the target cell via temporary PRACH resources fails, and it is determined that temporary PRACH resources are available in the second time;

[0210] If the first duration is less than or equal to the interval duration threshold, random access is initiated to the target cell through temporary PRACH resources at the second time; the first duration is the interval duration between the first time and the second time.

[0211] When the first duration exceeds the interval duration threshold, random access is initiated to the target cell using conventional PRACH resources.

[0212] As one embodiment, the first transceiver unit 1610 can be a transceiver 1830, and the first processing unit 1620 can be a processor 1810. The first node 1100 may also include a memory 1820, as shown in Figure 13.

[0213] Figure 17 is a schematic diagram of the structure of a node used for wireless communication according to another embodiment of this application. The node 1700 shown in Figure 17 can be any of the second nodes described above. The node 1700 may include a second transceiver module 1710 and a second processing module 1720.

[0214] The second transceiver module 1710 can be used to receive third information from the target cell, the third information including the first PRACH resource information of the target cell and the effective time period of the first PRACH resource; the second processing module 1720 can be used to send first information to the first node, the first information being used to determine the effective time period of the first PRACH resource of the target cell, so that the first node can use the first PRACH resource to initiate random access to the target cell within the effective time period of the first PRACH resource.

[0215] In some possible embodiments, outside the valid period of the first PRACH resource, the first PRACH resource is no longer used to initiate random access to the target cell.

[0216] In some possible embodiments, the first information is a first timer, the duration of which is determined based on the effective period of the first PRACH resource. When the first timer expires, the first PRACH resource will expire or expire simultaneously.

[0217] In some possible embodiments, the first information is carried in a switching command or an LTM command.

[0218] In some possible embodiments, the first PRACH resource is a regular PRACH resource or a temporary PRACH resource.

[0219] In some possible embodiments, the first information is also used to indicate that the first PRACH resource is a temporary PRACH resource.

[0220] In some possible embodiments, the handover command or LTM command may further include information on the second PRACH resource of the target cell configured for the first node.

[0221] In some possible embodiments, the second transceiver module 1710 can be used to receive fourth information from the target cell, the fourth information including first PRACH resource information and second PRACH resource information of the target cell and the effective time period of the first PRACH resource, wherein the first PRACH resource information is a temporary PRACH resource and the second PRACH resource information is a regular PRACH resource;

[0222] The first node sends second information, which includes information on the first PRACH resource and the second PRACH resource of the target cell; the second information includes first indication information, which is used to determine the effective time period of the first PRACH resource of the target cell; so that the first node can determine the target PRACH resource from the first PRACH resource and the second PRACH resource, and initiate random access to the target cell through the target PRACH resource.

[0223] In some possible embodiments, the target PRACH resource satisfies at least one of the following:

[0224] The target PRACH resource is the PRACH resource that is closest to the current time among the first PRACH resource and the second PRACH resource;

[0225] The target PRACH resource is a temporary PRACH resource that is preferentially selected by the network side;

[0226] The target PRACH resource is a regular PRACH resource that is preferentially selected by the network side.

[0227] As one embodiment, the second transceiver module 1210 can be a transceiver 1830. Node 1700 may also include a processor 1810 and a memory 1820, as shown in FIG18.

[0228] Figure 18 is a schematic structural diagram of a communication device according to an embodiment of this application. The dashed lines in Figure 18 indicate that the unit or module is optional. This device 1800 can be used to implement the methods described in the above method embodiments. Device 1800 can be a chip, user equipment, or network device.

[0229] Apparatus 1800 may include one or more processors 1810. The processor 1810 may support apparatus 1800 in implementing the methods described in the preceding method embodiments. The processor 1810 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0230] The apparatus 1800 may further include one or more memories 1820. The memories 1820 store a program that can be executed by the processor 1810, causing the processor 1810 to perform the methods described in the preceding method embodiments. The memories 1820 may be independent of the processor 1810 or integrated within the processor 1810.

[0231] The device 1800 may also include a transceiver 1830. The processor 1810 can communicate with other devices or chips via the transceiver 1830. For example, the processor 1810 can send and receive data with other devices or chips via the transceiver 1830.

[0232] Figure 19 is a schematic diagram of the hardware modules of the communication device provided in an embodiment of this application. Specifically, Figure 19 shows a block diagram of a first communication device 1950 and a second communication device 1910 communicating with each other in the access network.

[0233] The first communication device 1950 includes a controller / processor 1959, a memory 1960, a data source 1967, a transmitting processor 1968, a receiving processor 1956, a multi-antenna transmitting processor 1957, a multi-antenna receiving processor 1958, a transmitter / receiver 1954, and an antenna 1952.

[0234] The second communication device 1910 includes a controller / processor 1975, a memory 1976, a data source 1977, a receiver processor 1970, a transmitter processor 1916, a multi-antenna receiver processor 1972, a multi-antenna transmitter processor 1971, a transmitter / receiver 1918, and an antenna 1920.

[0235] In the transmission from the second communication device 1910 to the first communication device 1950, at the second communication device 1910, upper-layer data packets from the core network or from the data source 1977 are provided to the controller / processor 1975. The core network and data source 1977 represent all protocol layers above the L2 layer. The controller / processor 1975 implements the functionality of the L2 layer. In the transmission from the second communication device 1910 to the first communication device 1950, the controller / processor 1975 provides header compression, encryption, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation for the first communication device 1950 based on various priority metrics. The controller / processor 1975 is also responsible for retransmitting lost packets and signaling to the first communication device 1950. The transmit processor 1916 and the multi-antenna transmit processor 1971 implement various signal processing functions for the L1 layer (i.e., the physical layer). Transmit processor 1916 performs encoding and interleaving to facilitate forward error correction at the second communication device 1910, and mapping of signal clusters based on various modulation schemes (e.g., binary phase shift keying, quadrature phase shift keying, M-phase shift keying, M-quadrature amplitude modulation). Multi-antenna transmit processor 1971 performs digital spatial precoding on the encoded and modulated symbols, including codebook-based precoding and non-codebook-based precoding, and beamforming processing, generating one or more spatial streams. Transmit processor 1916 then maps each spatial stream to subcarriers, multiplexes it with a reference signal (e.g., a pilot) in the time and / or frequency domains, and subsequently uses inverse fast Fourier transform to generate a physical channel carrying the time-domain multicarrier symbol stream. Multi-antenna transmit processor 1971 then performs transmit analog precoding / beamforming operations on the time-domain multicarrier symbol stream. Each transmitter 1918 converts the baseband multicarrier symbol stream provided by the multi-antenna transmitter processor 1971 into an radio frequency stream, which is then provided to different antennas 1920.

[0236] In the transmission from the second communication device 1910 to the first communication device 1950, at the first communication device 1950, each receiver 1954 receives a signal through its corresponding antenna 1952. Each receiver 1954 recovers the information modulated onto the radio frequency carrier and converts the radio frequency stream into a baseband multicarrier symbol stream, which is then provided to the receiver processor 1956. The receiver processor 1956 and the multi-antenna receiver processor 1958 implement various signal processing functions of Layer 1. The multi-antenna receiver processor 1958 performs receive analog precoding / beamforming operations on the baseband multicarrier symbol stream from the receiver 1954. The receiver processor 1956 uses a fast Fourier transform to convert the baseband multicarrier symbol stream after the receive analog precoding / beamforming operations 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 receiver processor 1956, where the reference signal is used for channel estimation, and the data signal is recovered in the multi-antenna receiver processor 1958 after multi-antenna detection to recover any spatial stream destined for the first communication device 1950. Symbols on each spatial stream are demodulated and recovered in the receive processor 1956, generating soft decisions. The receive processor 1956 then decodes and deinterleaves the soft decisions to recover the upper-layer data and control signals transmitted by the second communication device 1910 over the physical channel. The upper-layer data and control signals are then provided to the controller / processor 1959. The controller / processor 1959 implements the functions of Layer 2. The controller / processor 1959 may be associated with a memory 1960 storing program code and data. The memory 1960 may be referred to as computer-readable media. In the transmission from the second communication device 1910 to the first communication device 1950, the controller / processor 1959 provides multiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transmission and logical channels to recover the upper-layer data packets from the second communication device 1910. The upper-layer data packets are then provided to all protocol layers above Layer 2. Various control signals may also be provided to Layer 3 for Layer 3 processing.

[0237] In the transmission from the first communication device 1950 to the second communication device 1910, at the first communication device 1950, upper-layer data packets are provided to the controller / processor 1959 using a data source 1967. The data source 1967 represents all protocol layers above the L2 layer. Similar to the transmission functions at the second communication device 1910 described in the transmission from the second communication device 1910 to the first communication device 1950, the controller / processor 1959 implements header compression, encryption, packet segmentation and reordering, and multiplexing between the logical and transport channels, implementing L2 layer functions for the user plane and control plane. The controller / processor 1959 is also responsible for retransmitting lost packets and signaling to the second communication device 1910. Transmit processor 1968 performs modulation mapping and channel coding processing, while multi-antenna transmit processor 1957 performs digital multi-antenna spatial precoding, including codebook-based and non-codebook-based precoding, and beamforming processing. Subsequently, transmit processor 1968 modulates the generated spatial stream into a multi-carrier / single-carrier symbol stream. After analog precoding / beamforming operations in multi-antenna transmit processor 1957, the stream is provided to different antennas 1952 via transmitter 1954. Each transmitter 1954 first converts the baseband symbol stream provided by multi-antenna transmit processor 1957 into a radio frequency symbol stream before providing it to antenna 1952.

[0238] In the transmission from the first communication device 1950 to the second communication device 1910, the function of the second communication device 1910 is similar to the receiving function of the first communication device 1950 described in the transmission from the second communication device 1910 to the first communication device 1950. Each receiver 1918 receives radio frequency signals through its corresponding antenna 1920, converts the received radio frequency signals into baseband signals, and provides the baseband signals to the multi-antenna receiving processor 1972 and the receiving processor 1970. The receiving processor 1970 and the multi-antenna receiving processor 1972 jointly implement the L1 layer function. The controller / processor 1975 implements the L2 layer function. The controller / processor 1975 may be associated with a memory 1976 that stores program code and data. The memory 1976 may be referred to as computer-readable media. In the transmission from the first communication device 1950 to the second communication device 1910, the controller / processor 1975 provides multiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transmission and logical channels to recover the upper-layer data packets from the first communication device 1950. The upper-layer data packets from the controller / processor 1975 can be provided to the core network or all protocol layers above Layer 2, and various control signals can also be provided to the core network or Layer 3 for Layer 3 processing.

[0239] As one embodiment, the first communication device 1950 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 with the at least one processor, and the first communication device 1950 at least: receives first information, the first information being used to determine the effective period of a first PRACH resource of a target cell; and during the effective period of the first PRACH resource, initiates random access to the target cell using the first PRACH resource.

[0240] As an example, the first communication device 1950 corresponds to the first node in this application.

[0241] As an example, the second communication device 1910 corresponds to the second node in this application.

[0242] As an example, the first communication device 1950 is an NCR.

[0243] As an example, the first communication device 1950 is a wireless repeater.

[0244] As an example, the first communication device 1950 is a relay.

[0245] As an example, the first communication device 1950 is a user equipment that can act as a relay node.

[0246] As an example, the first communication device 1950 is a V2X-enabled user equipment that can act as a relay node.

[0247] As an example, the first communication device 1950 is a D2D-enabled user equipment that can act as a relay node.

[0248] As one embodiment, the second communication device 1910 is a base station.

[0249] As one embodiment, the antenna 1952, the receiver 1954, the multi-antenna receiving processor 1958, the receiving processor 1956, and the controller / processor 1959 are used to receive the first information and / or the second information in this application.

[0250] As one embodiment, the antenna 1920, the transmitter 1918, the multi-antenna transmission processor 1971, the transmission processor 1916, and the controller / processor 1975 are used to transmit the first information and / or the second information in this application.

[0251] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal or network device provided in this application, and the program causes a computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0252] This application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0253] This application also provides a computer program. This computer program can be applied to the terminal or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0254] It should be understood that the terms "system" and "network" in this application can be used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0255] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0256] In the embodiments of this application, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0257] In the embodiments of this application, the term "correspondence" can indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0258] In this application embodiment, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including user equipment and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0259] In this application embodiment, the "protocol" may refer to a standard protocol in the field of communication, such as the LTE protocol, the NR protocol, and related protocols applied to future communication systems. This application does not limit this.

[0260] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0261] In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0262] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0263] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0264] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0265] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can read or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs) or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0266] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for a first node in wireless communication, characterized in that, include: Receive first information, which is used to determine the effective time period of the first PRACH resource of the target cell; During the valid period of the first PRACH resource, a random access is initiated to the target cell using the first PRACH resource.

2. The method according to claim 1, characterized in that, Also includes: Outside of the effective period of the first PRACH resource, the first PRACH resource will no longer be used to initiate random access to the target cell.

3. The method according to claim 1 or 2, characterized in that, The first information is the first timer.

4. The method according to claim 3, characterized in that, The duration of the first timer is determined based on the effective time period of the first PRACH resource.

5. The method according to claim 3, characterized in that, The first information is carried in the switching command or the LTM command.

6. The method according to any one of claims 1 to 5, characterized in that, The first PRACH resource is a regular PRACH resource or a temporary PRACH resource.

7. The method according to claim 1 or 2, characterized in that, The first information is also used to indicate that the first PRACH resource is a temporary PRACH resource.

8. The method according to claim 5, characterized in that, The handover command or LTM command also includes information about the second PRACH resource of the target cell configured for the first node.

9. The method according to claim 8, characterized in that, Also includes: Outside the valid period of the first PRACH resource, the second PRACH resource is used to initiate random access to the target cell.

10. A method for a first node in wireless communication, characterized in that, include: Receive second information, which includes first PRACH resource information and second PRACH resource information of the target cell; The first PRACH resource information is a temporary PRACH resource, and the second PRACH resource information is a regular PRACH resource; the second information includes first indication information, which is used to determine the effective time period of the first PRACH resource of the target cell; The target PRACH resource is determined from the first PRACH resource and the second PRACH resource, and random access is initiated to the target cell through the target PRACH resource.

11. The method according to claim 10, characterized in that, The target PRACH resource satisfies at least one of the following: The target PRACH resource is the PRACH resource that is closest to the current time among the first PRACH resource and the second PRACH resource; The target PRACH resource is a temporary PRACH resource that is preferentially selected by the network side; The target PRACH resource is a regular PRACH resource that is preferentially selected by the network side; The target PRACH resource is a regular PRACH resource that is preferentially selected by the protocol.

12. The method according to claim 10, characterized in that, Also includes: When the first attempt to initiate random access to the target cell via temporary PRACH resources fails, and it is determined that temporary PRACH resources are available in the second time; If the first duration is less than or equal to the interval duration threshold, random access is initiated to the target cell through temporary PRACH resources at the second time; the first duration is the interval duration between the first time and the second time. When the first duration exceeds the interval duration threshold, random access is initiated to the target cell using conventional PRACH resources.

13. A method for a second node in wireless communication, characterized in that, include: Receive third information from the target cell, the third information including the first PRACH resource information of the target cell and the effective time period of the first PRACH resource; The first node sends first information, which is used to determine the effective period of the first PRACH resource of the target cell, so that the first node can use the first PRACH resource to initiate random access to the target cell during the effective period of the first PRACH resource.

14. The method according to claim 13, characterized in that, Outside of the effective period of the first PRACH resource, the first PRACH resource will no longer be used to initiate random access to the target cell.

15. The method according to claim 13 or 14, characterized in that, The first information is the first timer.

16. The method according to claim 15, characterized in that, The duration of the first timer is determined based on the effective time period of the first PRACH resource.

17. The method according to claim 15, characterized in that, The first information is carried in the switching command or the LTM command.

18. The method according to any one of claims 13 to 17, characterized in that, The first PRACH resource is a regular PRACH resource or a temporary PRACH resource.

19. The method according to claim 13 or 14, characterized in that, The first information is also used to indicate that the first PRACH resource is a temporary PRACH resource.

20. The method according to claim 17, characterized in that, The handover command or LTM command also includes information about the second PRACH resource of the target cell configured for the first node.

21. A method for a second node in wireless communication, characterized in that, include: Receive fourth information from the target cell, the fourth information including first PRACH resource information and second PRACH resource information of the target cell and the effective time period of the first PRACH resource, wherein the first PRACH resource information is a temporary PRACH resource and the second PRACH resource information is a regular PRACH resource; The first node sends second information, which includes information on the first PRACH resource and the second PRACH resource of the target cell; the second information includes first indication information, which is used to determine the effective time period of the first PRACH resource of the target cell; so that the first node can determine the target PRACH resource from the first PRACH resource and the second PRACH resource, and initiate random access to the target cell through the target PRACH resource.

22. The method according to claim 21, characterized in that, The target PRACH resource satisfies at least one of the following: The target PRACH resource is the PRACH resource that is closest to the current time among the first PRACH resource and the second PRACH resource; The target PRACH resource is a temporary PRACH resource that is preferentially selected by the network side; The target PRACH resource is a regular PRACH resource that is preferentially selected by the network side; The target PRACH resource is a regular PRACH resource that is preferentially selected by the protocol.

23. A communication device, characterized in that, Includes units or modules for performing the method as described in any one of claims 1-9 or 10-12.

24. A communication device, characterized in that, Includes units or modules for performing the method as described in any one of claims 13-20 or 21-22.

25. A first node used for wireless communication, characterized in that, It includes a transceiver, a memory, and a processor, wherein the memory is used to store a program, the processor is used to invoke the program in the memory, and to control the transceiver to receive or send signals so that the node performs the method as described in any one of claims 1-9 or 10-12.

26. A second node used for wireless communication, characterized in that, The device includes a transceiver, a memory, and a processor. The memory is used to store a program, and the processor is used to invoke the program in the memory and control the transceiver to receive or send signals so that the node performs the method as described in any one of claims 13-20 or 21-22.

27. A communication device, characterized in that, Includes at least one processor; and One or more non-transitory computer-readable storage media, said one or more non-transitory computer-readable storage media coupled to said at least one processor and storing programming instructions executable by said at least one processor, said programming instructions, when executed, cause said at least one processor to perform the method as described in any one of claims 1-9, 10-12, 13-20 or 21-22.

28. A chip, characterized in that, Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1-9, 10-12, 13-20, or 21-22.

29. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1-9, 10-12, 13-20 or 21-22.

30. A computer program product, characterized in that, Includes a program that causes a computer to perform the method as described in any one of claims 1-9, 10-12, 13-20, or 21-22.

31. A computer program, characterized in that, The computer program causes the computer to perform the method as described in any one of claims 1-9, 10-12, 13-20, or 21-22.

Images