A method and device for wireless communication

Abstract

The present application discloses a method and device for wireless communication, including: starting a first timer; selecting a first service cell; sending a first wireless signal, the first wireless signal including a first message, the first message being used to request RRC reconstruction; starting a second timer along with sending the first message; operating the first timer according to a transmission method at least to the first service cell; sending a third wireless signal, the third wireless signal including a third message, the third message being used to request an RRC connection; the present application ensures service continuity and reduces interruptions by reasonably controlling the first timer and the second timer.

Description

Technical Field

[0001] The present application relates to a transmission method and device in a wireless communication system, and more particularly to a method and device for reducing service interruption, improving service continuity, enhancing reliability, and ensuring security in wireless communications. Background Art

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

[0003] In communication, both LTE (Long Term Evolution) and 5G NR involve accurate reception of reliable information, optimized energy efficiency, determination of information validity, flexible resource allocation, scalable system structure, efficient non-access layer information processing, low service interruption and drop rate, and support for low power consumption. This is of great significance to the normal communication between base stations and user equipment, the reasonable scheduling of resources, and the balancing of system loads. It can be said to be the cornerstone of high throughput, meeting the communication needs of various services, improving spectrum utilization, and improving service quality. It is indispensable for eMBB (ehanced Mobile BroadBand), URLLC (Ultra Reliable Low Latency Communication) and eMTC (enhanced Machine Type Communication). At the same time, there are extensive demands in IIoT (Industrial Internet of Things, Industrial Internet of Things, V2X (Vehicular to X), Device to Device, unlicensed spectrum communication, user communication quality monitoring, network planning optimization, NTN (Non Territerial Network), TN (Territial Network), dual connectivity systems, wireless resource management and multi-antenna codebook selection, signaling design, neighbor management, service management, and beamforming. Information transmission methods are divided into broadcast and unicast. Both transmission methods are essential for 5G systems because they are very helpful in meeting the above requirements. Reducing device costs is also a very important aspect. The aspects involved in reducing costs include reduced capabilities and various IoT devices.

[0004] As the scenarios and complexity of the system continue to increase, higher requirements are placed on reducing interruption rates, reducing latency, enhancing reliability, enhancing system stability, business flexibility, and power saving. At the same time, compatibility between different versions of different systems also needs to be considered during system design. Summary of the invention

[0005] In various communication scenarios, the establishment and reconstruction of entities and links are involved. In particular, in the case of key update, the relevant entities need to be rebuilt to ensure security. When encryption is performed by the PDCP entity, the relevant PDCP entity will be rebuilt. In scenarios involving relays, communication between UEs is involved. The relay can be another UE. This UE as a relay node can be stationary or mobile, such as a car. Generally speaking, the communication range of the relay node is smaller than the service cell. The relay node is often used to appropriately expand the service range of the service cell or solve problems such as wireless shadows and building obstructions within the coverage. Short distances plus movement or rapid movement are more likely to cause unstable communication between the remote UE and the relay node. Compared with a stationary service cell with a larger coverage, the link between the remote node and the relay node is more unstable. The remote node may need to change the relay node more frequently and restore the connection with the service cell more frequently. When restoring the connection with the service cell, the reconstruction of the RRC connection is involved. If the key of the new service cell is changed, the reconstruction of the PDCP entity may also be involved. During the process of reestablishing the connection between the remote node and the network through the relay, the wireless link between the remote node and the relay node and between the relay node and the service cell may fail or have failed, or the access to the relay node is denied or the relay node cannot provide relay services, etc. Therefore, during the reestablishment process, the UE may need to try to reestablish the RRC connection multiple times through different relay nodes until the RRC connection succeeds or the time limit is exceeded. Existing technologies for non-relay situations cannot support the rapid replacement of different nodes to initiate reestablishment or access requests, so the delay is large and data interruption is easy to occur.

[0006] With regard to the above-mentioned problems, this application provides a solution.

[0007] It should be noted that, in the absence of conflict, the embodiments and features in any node of the present application can be applied to any other node. In the absence of conflict, the embodiments and features in the embodiments of the present application can be arbitrarily combined with each other.

[0008] The present application discloses a method in a first node used for wireless communication, comprising:

[0009] Starting a first timer; selecting a first serving cell; sending a first wireless signal, the first wireless signal including a first message, the first message being used to request RRC reestablishment; starting a second timer along with sending the first message; operating the first timer according to a transmission mode at least to the first serving cell; sending a third wireless signal, the third wireless signal including a third message, the third message being used to request an RRC connection;

[0010] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission method to at least the first service cell, including: when the transmission method to the first service cell is through relay transmission, stopping the first timer in response to selecting the first service cell; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0011] As an embodiment, the problem to be solved by the present application includes: how to quickly attempt RRC reconstruction in an unstable communication network, especially when relay is involved, to reduce data interruption and provide business continuity.

[0012] As an embodiment, the benefits of the above method include: the method proposed in the present application can solve the above problems. When a UE initiates reconstruction, the first timer is started. In an unstable network, such as when transmitting through a relay, it is stopped only when it receives reconstruction feedback from the network. Multiple attempts can be made quickly during this period, instead of terminating the timer when an attempt is initiated or when an attempt is about to be initiated.

[0013] Specifically, according to one aspect of the present application, a second wireless signal is received, the second wireless signal includes a second message, and the second message is used to determine that the first message is not successfully distributed.

[0014] Specifically, according to one aspect of the present application, the second message is used to trigger stopping the first timer and the second timer, and the first node enters an RRC idle state;

[0015] The third wireless signal is sent when the first node enters the RRC idle state; and the third message is used to request to establish an RRC connection.

[0016] Specifically, according to one aspect of the present application, the second message is used to trigger the restart of the second timer and send the third message; the third message is used to request RRC reconstruction.

[0017] Specifically, according to one aspect of the present application, a fourth wireless signal is received, where the fourth wireless signal includes a fourth message, where the fourth message is used to feed back the third message;

[0018] The fourth message is used to trigger and stop the first timer and the second timer.

[0019] Specifically, according to one aspect of the present application, the second message is used to trigger reselection of the relay.

[0020] Specifically, according to one aspect of the present application, a failure of a first wireless link is detected, and the first wireless signal is sent through the first wireless link;

[0021] In response to detecting the failure of the first radio link, the second timer is stopped and selection of a serving cell is performed.

[0022] Specifically, according to one aspect of the present application, a first discovery signal is received, where the first discovery signal is used to indicate a first service cell; and the behavior of selecting the first service cell includes selecting a sender of the first discovery signal as a relay.

[0023] Specifically, according to one aspect of the present application, the first message is the Nth RRC reconstruction request attempt initiated by the first timer during operation, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; the transmission method of the N RRC reconstruction requests to the first service cell is through relay transmission.

[0024] Specifically, according to one aspect of the present application, a first timer is started; a first serving cell is selected; a first wireless signal is sent, the first wireless signal includes a first message, and the first message is used to request RRC reestablishment; along with sending the first message, a second timer is started; the first timer is operated according to a transmission mode at least to the first serving cell; a third wireless signal is sent, the third wireless signal includes a third message, and the third message is used to request an RRC connection;

[0025] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission mode to at least the first service cell, including: when the transmission mode to the first service cell is direct transmission, as a response to selecting the first service cell, stopping the first timer; when the transmission mode to the first service cell is through relay transmission, continuing to run the first timer after the behavior selects the first service cell.

[0026] Specifically, according to one aspect of the present application, the first node is a user equipment.

[0027] Specifically, according to one aspect of the present application, the first node is an Internet of Things terminal.

[0028] Specifically, according to one aspect of the present application, the first node is a relay.

[0029] Specifically, according to one aspect of the present application, the first node is a vehicle-mounted terminal.

[0030] Specifically, according to one aspect of the present application, the first node is an aircraft.

[0031] The present application discloses a first node used for wireless communication, comprising:

[0032] A first transmitter starts a first timer; selects a first serving cell; sends a first wireless signal, wherein the first wireless signal includes a first message, wherein the first message is used to request RRC reestablishment; starts a second timer along with sending the first message; operates the first timer according to a transmission mode at least to the first serving cell; sends a third wireless signal, wherein the third wireless signal includes a third message, wherein the third message is used to request RRC connection;

[0033] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission method to at least the first service cell, including: when the transmission method to the first service cell is through relay transmission, stopping the first timer in response to selecting the first service cell; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0034] As an embodiment, compared with the traditional solution, the present application has the following advantages: the method proposed in the present application can support the remote node (remote UE) to attempt to reestablish the RRC connection multiple times during the operation of the first timer during the process of starting the RRC connection reconstruction, thereby increasing the success rate of the RRC connection reconstruction, reducing data interruption, and improving reliability, and is particularly suitable for networks using relay communications.

[0035] As an embodiment, compared with the traditional solution, the present application has the following advantages: the method proposed in the present application can quickly reselect the relay and initiate the reconstruction again after the remote node receives feedback from the relay node that can determine the failure of sending the reconstruction request message.

[0036] As an embodiment, compared with the traditional solution, the present application has the following advantages: the method proposed in the present application can quickly choose to directly connect to the network or select other relays to initiate a new RRC establishment request after the remote node receives feedback from the relay node that can determine the failure of the reconstruction request message to be sent. It can also save time and re-enter the connection network more quickly without waiting for the second timer to expire, that is, terminating the second timer in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0038] Figure 1 A flowchart showing starting a first timer, selecting a first serving cell, sending a first wireless signal, and sending a third wireless signal according to an embodiment of the present application is shown;

[0039] Figure 2 A schematic diagram of a network architecture according to an embodiment of the present application is shown;

[0040] Figure 3 A schematic diagram showing an embodiment of a wireless protocol architecture of a user plane and a control plane according to an embodiment of the present application;

[0041] Figure 4 A schematic diagram of a first node according to an embodiment of the present application is shown;

[0042] Figure 5 A flow chart showing transmission according to an embodiment of the present application is shown;

[0043] Figure 6 A flow chart showing transmission according to an embodiment of the present application is shown;

[0044] Figure 7 A schematic diagram showing a candidate node group according to an embodiment of the present application is shown;

[0045] Figure 8 A schematic diagram showing that a second message is used to determine that a first message is not successfully distributed according to an embodiment of the present application;

[0046] Fig. 9 A schematic diagram showing a second message being used to trigger reselection of a relay according to an embodiment of the present application;

[0047] Fig.10 The following is a schematic diagram illustrating a processing device used in a first node according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] The technical solution of the present application will be further described in detail below in conjunction with the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments in the present application and the features in the embodiments can be combined with each other arbitrarily.

[0049] Example 1

[0050] Embodiment 1 illustrates a flowchart of starting a first timer, selecting a first serving cell, sending a first wireless signal, and sending a third wireless signal according to an embodiment of the present application, as shown in the attached figure. Figure 1 Attached Figure 1In the figure, each box represents a step. It should be emphasized that the order of the boxes in the figure does not represent the temporal relationship between the steps represented.

[0051] In Embodiment 1, the first node in the present application starts a first timer in step 101; selects a first serving cell in step 102; sends a first wireless signal in step 103; and sends a third wireless signal in step 104;

[0052] Among them, the first wireless signal includes a first message, and the first message is used to request RRC reconstruction; a second timer is started along with sending the first message; the first timer is operated according to a transmission method at least to the first service cell; the third wireless signal includes a third message, and the third message is used to request an RRC connection; expiration of the first timer is used to trigger the first node to enter an RRC idle state; the behavior of operating the first timer according to the transmission method at least to the first service cell includes: when the transmission method to the first service cell is through relay transmission, as a response to selecting the first service cell, stopping the first timer; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0053] As an embodiment, the first node is a UE (User Equipment).

[0054] As an embodiment, the first wireless signal is sent at the PC5 interface.

[0055] As an embodiment, the first wireless signal is sent via a secondary link.

[0056] As an embodiment, the third wireless signal is sent via a secondary link.

[0057] As an embodiment, the physical channel occupied by the first wireless signal includes PSSCH (Physical Sidelink Shared Channel).

[0058] As an embodiment, the first wireless signal includes a first MAC PDU, the first MAC PDU includes a first MAC sub-PDU, the header of the first MAC sub-PDU is a first MAC sub-header, the first MAC sub-header includes the 16 most significant bits of a first identity and the 8 most significant bits of a second identity; the first identity is used to identify the first node.

[0059] As a sub-embodiment of the above embodiment, the first identity and the second identity are link layer identities respectively.

[0060] As a sub-embodiment of the above embodiment, the first identity and the second identity are Layer-2 identities respectively.

[0061] As a sub-embodiment of the above embodiment, the second identity is used to identify a second node; the second node is a relay node of the first node.

[0062] As a sub-embodiment of the above embodiment, the second identity is used to identify a relay of the first node.

[0063] As a sub-embodiment of the above embodiment, the second identity is used to identify a receiver of the first wireless signal.

[0064] As a sub-embodiment of the above embodiment, the second identity is used to identify the recipient of the first message.

[0065] As a sub-embodiment of the above embodiment, the node that the second identity is used to identify is a node other than the generator of the first message.

[0066] As an embodiment, the physical channel occupied by the first wireless signal includes PUSCH (Physical Uplink Shared Channel).

[0067] As an embodiment, the first wireless signal is sent via a main link.

[0068] As an embodiment, when the transmission method to the first service cell is through relay transmission, the receiver of the first wireless signal is a relay node.

[0069] As an embodiment, when the transmission method to the first service cell is through relay transmission, the first wireless signal includes a first MAC PDU, the first MAC PDU includes a first MAC sub-PDU, the header of the first MAC sub-PDU is a first MAC sub-header, the first MAC sub-header includes the 16 most significant bits of a first identity and the 8 most significant bits of a second identity; the first identity is used to identify the first node.

[0070] As an embodiment, when the transmission method to the first serving cell is through relay transmission, the first wireless signal is sent along with SCI (Sidelink Control Information).

[0071] As an embodiment, when the transmission method to the first serving cell is through relay transmission, the first wireless signal is sent on a secondary link.

[0072] As an embodiment, when the transmission mode to the first service cell is direct transmission, the receiver of the first wireless signal is the service cell.

[0073] As a sub-embodiment of the above embodiment, the receiver of the first wireless signal is the first serving cell.

[0074] As a sub-embodiment of the above embodiment, the first wireless signal carries the msg3 message.

[0075] As a sub-embodiment of the above embodiment, the first wireless signal is a msg3 message.

[0076] As a sub-embodiment of the above embodiment, the first wireless signal is sent on the resources indicated by a RAR (Random Access Response).

[0077] As a sub-embodiment of the above embodiment, the first wireless signal occupies a PUSCH channel.

[0078] As an embodiment, the first wireless signal is a physical layer signal.

[0079] As an embodiment, the first timer is a timer of the RRC layer; or, the first timer is maintained by the RRC layer.

[0080] As an embodiment, the first timer is started when the first node initiates RRC connection reconstruction.

[0081] As an embodiment, the first timer is started as a response to the first node initiating a RRC Re-establishment process.

[0082] As an embodiment, expiration of the first timer triggers the first node to enter the RRC IDLE state.

[0083] As an embodiment, the first timer includes T311.

[0084] As an embodiment, the first timer is T311.

[0085] As an embodiment, the first timer is not T311.

[0086] As an embodiment, the first timer is a timer related to the relay.

[0087] As an embodiment, the name of the first timer includes r or relay.

[0088] As an embodiment, the name of the first timer includes T1 or T2.

[0089] As an embodiment, the name of the first timer includes T4.

[0090] As an embodiment, the first timer is T411.

[0091] As an embodiment, the first timer is T301.

[0092] As an embodiment, the first timer is T401.

[0093] As an embodiment, the first timer is T402.

[0094] As an embodiment, the first timer and T311 are started simultaneously.

[0095] As an embodiment, the first message includes RRCReestablishmentRequest.

[0096] As an embodiment, the first message includes RRCConnectionReestablishmentRequest.

[0097] As an embodiment, the first message is RRCReestablishmentRequest.

[0098] As an embodiment, the first message is RRCConnectionReestablishmentRequest.

[0099] As an embodiment, the first message includes ue-Identity.

[0100] As an embodiment, the first message includes reestablishmentCause.

[0101] As an embodiment, the first message includes c-RNTI.

[0102] As an embodiment, the first message includes physCellId.

[0103] As an embodiment, the first message includes shortMAC-I.

[0104] As an embodiment, the physCellId included in the first message is used to indicate the physical cell identity of the Pcell to which the first node is connected before failure.

[0105] As an embodiment, the first message is sent through a fixed configuration.

[0106] As an embodiment, the first message is sent through the PC5 interface.

[0107] As an embodiment, the first message includes a PC5-RRC message.

[0108] As an embodiment, the first message includes a PC5-S message.

[0109] As an embodiment, the first message is encrypted.

[0110] As an embodiment, the first message is not encrypted.

[0111] As an embodiment, the RLC channel occupied by the first message is fixed.

[0112] As an embodiment, the relay of the first node generates an RRCReestablishmentRequest message according to the first message, and sends the generated RRCReestablishmentRequest to the first serving cell.

[0113] As an embodiment, the receiver of the first wireless signal generates an RRCReestablishmentRequest message according to the first message, and sends the generated RRCReestablishmentRequest to the first serving cell.

[0114] As an embodiment, the relay of the first node forwards the first message to the first serving cell.

[0115] As an embodiment, the phrase selecting the first serving cell includes: performing cell selection to select a suitable cell.

[0116] As an embodiment, the phrase selecting a first serving cell includes: performing cell selection, selecting an acceptable cell.

[0117] As an embodiment, the phrase selecting the first serving cell includes: performing cell selection according to an S criterion to select a suitable cell.

[0118] As an embodiment, the phrase selecting the first service cell includes: determining the first service cell as a receiver of the first wireless signal.

[0119] As an embodiment, the phrase selecting the first service cell includes: determining the first service cell, and attempting to connect to the first service cell by direct transmission.

[0120] As an embodiment, the phrase selecting the first serving cell includes: determining the cell identity of the first serving cell through a SIB1 system message.

[0121] As an embodiment, the phrase selecting the first serving cell includes: performing relay selection.

[0122] As an embodiment, the phrase selecting a first service cell includes: performing relay selection, and the selected relay resides in the first service cell.

[0123] As an embodiment, the phrase selecting a first service cell includes: selecting a second node, the second node being a relay of the first node, and the second node having an RRC connection with the first service cell.

[0124] As an embodiment, the phrase selecting a first serving cell includes: selecting a second node, the second node being a relay of the first node, and a PCell of the second node being the first serving cell.

[0125] As an embodiment, the phrase selecting the first serving cell includes: selecting the first serving cell as a recipient of the first message.

[0126] As an embodiment, the phrase selecting the first serving cell includes: selecting a second node, and a discovery message sent by the second node includes the identity of the first serving cell.

[0127] As an embodiment, the phrase selecting a first serving cell includes: attempting RRC connection reestablishment on the first serving cell.

[0128] As an embodiment, the phrase selecting the first serving cell includes: setting reestablishmentCellId to the identity of the first serving cell.

[0129] As an embodiment, the phrase selecting the first serving cell includes: taking the first serving cell as a target cell for RRC reconstruction of the first node.

[0130] As an embodiment, the third message includes RRCSetupRequest.

[0131] As an embodiment, the third message includes RRCReestablishmentRequest.

[0132] As an embodiment, the third message includes RRCConnectionSetupRequest.

[0133] As an embodiment, the third message includes RRCConnectionReestablishmentRequest.

[0134] As an embodiment, when the first service cell is selected, the first timer is in a running state.

[0135] As an embodiment, selecting the first serving cell includes the first node selecting a relay according to signal quality, the selected relay resides in the first serving cell, or the selected relay establishes a connection with the first serving cell.

[0136] As an embodiment, the action of starting the second timer includes starting and restarting.

[0137] As an embodiment, the sentence is accompanied by sending the first message, and starting the second timer includes: when the first message is sent, the second timer is started or restarted.

[0138] As an embodiment, the sentence is accompanied by sending the first message, and starting the second timer includes: the behavior selects the first service cell to trigger the first message to be sent, and at the same time triggers the second timer to be started or restarted.

[0139] As an embodiment, the sentence is accompanied by sending the first message, and starting the second timer includes: starting the RRC reconstruction process to trigger the first message to be sent, and at the same time triggering the second timer to be started or restarted.

[0140] As an embodiment, the relay of the first node and the first serving cell use the same access technology.

[0141] As a sub-embodiment of the above embodiment, the relay of the first node is a second node.

[0142] As a sub-embodiment of the above embodiment, the relay of the first node is a receiver of the first wireless signal.

[0143] As an embodiment, the second timer is started when RRCReestablishmentRequest is sent.

[0144] As an embodiment, the second timer is started when RRCConnectionReestablishmentRequest is sent.

[0145] As an embodiment, the second timer is started when the RRCReestablishmentRequest message is sent.

[0146] As an embodiment, the second timer is started when the RRCConnectionReestablishmentRequest message is sent.

[0147] As an embodiment, the second timer is stopped when an RRCReestablishment message is received.

[0148] As an embodiment, the second timer is stopped when an RRCConnectionReestablishment message is received.

[0149] As an embodiment, the second timer is stopped when the RRCSetup message is received.

[0150] As an embodiment, the second timer is stopped when the RRCConnectionSetup message is received.

[0151] As an embodiment, the second timer includes T301.

[0152] As an embodiment, the second timer is T301.

[0153] As an embodiment, the second timer is not T301.

[0154] As an embodiment, the second timer is T305.

[0155] As an embodiment, the second timer is T306.

[0156] As an embodiment, the second timer is T307.

[0157] As an embodiment, the second timer is T308.

[0158] As an embodiment, the second timer is T309.

[0159] As an embodiment, the second timer is T301a.

[0160] As an embodiment, the second timer is T301b.

[0161] As an embodiment, the second timer is T301r.

[0162] As an embodiment, the second timer is T301c.

[0163] As an embodiment, the second timer is not T311.

[0164] As an embodiment, the second timer is T313.

[0165] As an embodiment, the second timer is T314.

[0166] As an embodiment, the second timer is T315.

[0167] As an embodiment, the second timer is T316.

[0168] As an embodiment, the second timer is T401.

[0169] As an embodiment, the second timer is T402.

[0170] As an embodiment, the second timer is T404.

[0171] As an embodiment, the second timer is T411.

[0172] As an embodiment, the second timer is T410.

[0173] As an embodiment, the second timer is T412.

[0174] As an embodiment, the second timer is T413.

[0175] As an embodiment, the second timer is T414.

[0176] As an embodiment, the second timer is T500.

[0177] As an embodiment, the second timer is T501.

[0178] As an embodiment, the second timer is T511.

[0179] As an embodiment, the second timer is T510.

[0180] As an embodiment, the second timer is T512.

[0181] As an embodiment, the second timer is T513.

[0182] As an embodiment, the second timer is T514.

[0183] As an embodiment, the name of the second timer includes r.

[0184] As an embodiment, the name of the second timer includes relay.

[0185] As an embodiment, the name of the second timer includes sl.

[0186] As an embodiment, the name of the second timer includes T1.

[0187] As an embodiment, the name of the second timer includes T2.

[0188] As an embodiment, expiration of the second timer triggers the first node to enter the RRC idle state.

[0189] As an embodiment, expiration of the second timer triggers the first node to perform RRC reconstruction.

[0190] As an embodiment, expiration of the second timer triggers the first node to perform relay selection.

[0191] As an embodiment, the expiration values ​​of the first timer and the second timer are fixed or preconfigured.

[0192] As an embodiment, the expiration values ​​of the first timer and the second timer are configured by a system message.

[0193] As an embodiment, the third wireless signal is sent at the PC5 interface.

[0194] As an embodiment, the physical channel occupied by the third wireless signal includes PSSCH (Physical Sidelink Shared Channel).

[0195] As an embodiment, the third wireless signal includes a first MAC PDU, the first MAC PDU includes a first MAC sub-PDU, the header of the first MAC sub-PDU is a first MAC sub-header, the first MAC sub-header includes the 16 most significant bits of a first identity and the 8 most significant bits of a second identity; the first identity is used to identify the first node.

[0196] As a sub-embodiment of the above embodiment, the first identity and the second identity are link layer identities respectively.

[0197] As a sub-embodiment of the above embodiment, the first identity and the second identity are Layer-2 identities respectively.

[0198] As a sub-embodiment of the above embodiment, the second identity is used to identify a second node; the second node is a relay node of the first node.

[0199] As a sub-embodiment of the above embodiment, the second identity is used to identify a relay of the first node.

[0200] As a sub-embodiment of the above embodiment, the second identity is used to identify a receiver of the third wireless signal.

[0201] As a sub-embodiment of the above embodiment, the second identity is used to identify the recipient of the first message.

[0202] As a sub-embodiment of the above embodiment, the node that the second identity is used to identify is a node other than the generator of the first message.

[0203] As a sub-embodiment of the above embodiment, the node that the second identity is used to identify is a node other than the first node and the second node.

[0204] As an embodiment, the physical channel occupied by the third wireless signal includes PUSCH (Physical Uplink Shared Channel).

[0205] As an embodiment, the third wireless signal is sent via the main link.

[0206] As an embodiment, when the transmission method to the first service cell is through relay transmission, the receiver of the third wireless signal is a relay node.

[0207] As an embodiment, when the transmission method to the first service cell is through relay transmission, the third wireless signal includes a first MAC PDU, the first MAC PDU includes a first MAC sub-PDU, the header of the first MAC sub-PDU is a first MAC sub-header, and the first MAC sub-header includes the 16 most significant bits of a first identity and the 8 most significant bits of a second identity; the first identity is used to identify the first node.

[0208] As an embodiment, when the transmission method to the first service cell is through relay transmission, the third wireless signal is sent along with SCI (Sidelink Control Information).

[0209] As an embodiment, when the transmission method to the first service cell is through relay transmission, the third wireless signal is sent on a secondary link.

[0210] As an embodiment, when the transmission mode to the first service cell is direct transmission, the receiver of the third wireless signal is the service cell.

[0211] As a sub-embodiment of the above embodiment, the recipient of the third wireless signal is the first serving cell.

[0212] As a sub-embodiment of the above embodiment, the third wireless signal carries the msg3 message.

[0213] As a sub-embodiment of the above embodiment, the third wireless signal is a msg3 message.

[0214] As a sub-embodiment of the above embodiment, the third wireless signal is sent on the resources indicated by RAR (Random Access Response).

[0215] As a sub-embodiment of the above embodiment, the third wireless signal occupies a PUSCH channel.

[0216] As an embodiment, the third wireless signal is a physical layer signal.

[0217] As an embodiment, the behavior of operating the first timer only includes one of stopping the first timer or continuing to run the first timer.

[0218] As an embodiment, the transmission mode of the first service cell includes only one of relay transmission and direct transmission.

[0219] As an embodiment, the transmission method of the first service cell through relay transmission means indirect transmission.

[0220] As an embodiment, the first node determines the transmission mode of the first service cell according to pre-configuration.

[0221] As an embodiment, the first node determines the transmission mode of the first service cell according to parameters provided by a system message.

[0222] As an embodiment, the first node determines the transmission mode of the first service cell according to an internal algorithm.

[0223] As an embodiment, the first node determines the transmission mode of the first service cell based on measurement results including signal strength.

[0224] As an embodiment, when the transmission mode to the first service cell is through relay transmission, the relay mode of the relay transmission is layer 2 relay.

[0225] As an embodiment, when the transmission mode to the first service cell is through relay transmission, the relay mode of the relay transmission is L2 relay.

[0226] As an embodiment, when the transmission mode to the first serving cell is through relay transmission, the relay mode of the relay transmission is Layer 2 relay.

[0227] As an embodiment, when the transmission mode to the first service cell is through relay transmission, the relay mode of the relay transmission is Class 2 relay.

[0228] As an embodiment, when the transmission mode to the first service cell is through relay transmission, the relay mode of the relay transmission is a first type of relay.

[0229] As an embodiment, the sentence includes the following meaning when the transmission mode to the first service cell is direct transmission, that is, the counterpart of the physical layer of the first node is maintained by the first service cell.

[0230] As an embodiment, the sentence includes the following meaning when the transmission mode to the first serving cell is direct transmission, that is, the counterpart of the MAC entity of the first node is maintained by the first serving cell.

[0231] As an embodiment, the sentence includes the following meaning when the transmission mode to the first serving cell is direct transmission, that is, the counterpart RLC entity of the RLC entity of the first node is maintained by the first serving cell.

[0232] As an embodiment, the sentence includes the following meaning when the transmission method to the first service cell is through relay transmission, and the counterpart of the physical layer of the first node is maintained by a relay node.

[0233] As an embodiment, the sentence includes the following meaning when the transmission method to the first service cell is through relay transmission, and the counterpart of the MAC entity of the first node is maintained by a relay node.

[0234] As an embodiment, the sentence includes the following meaning when the transmission method to the first service cell is through relay transmission, and the counterpart RLC entity of the RLC entity of the first node is maintained by a relay node.

[0235] As an embodiment, the sentence includes the following meaning when the transmission method to the first service cell is through relay transmission, and the first message is forwarded to the first service cell by the relay.

[0236] As an embodiment, the sentence includes the following meaning when the transmission method to the first service cell is through relay transmission: the relay generates an RRCReestablishmentRequest according to the first message and sends it to the first service cell.

[0237] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is direct transmission, maintaining the running state of the first timer after the behavior selects the first service cell.

[0238] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is direct transmission, selecting the first service cell is not used to trigger stopping the first timer.

[0239] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is direct transmission, the condition for stopping the first timer does not include the selection of the first service cell.

[0240] As an embodiment, the sentence stating that the first timer continues to run after the behavior selects the first service cell includes the following meaning: the first timer is not stopped after the behavior selects the first service cell.

[0241] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is through relay transmission, maintaining the running state of the first timer after the behavior selects the first service cell.

[0242] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is through relay transmission, selecting the first service cell is not used to trigger stopping the first timer.

[0243] As an embodiment, the sentence describing continuing to run the first timer after the behavior selects the first service cell includes the following meaning: when the transmission method to the first service cell is through relay transmission, the condition for stopping the first timer does not include the first service cell being selected.

[0244] As an embodiment, the sentence stating that the first timer continues to run after the behavior selects the first service cell includes the following meaning: the first timer is not stopped after the behavior selects the first service cell.

[0245] As an embodiment, as a response to initiating the RRC reconstruction process, the first node sends an RRC reconstruction request message and starts the second timer, and the expiration of the second timer is used to trigger the third wireless signal.

[0246] As an embodiment, as a response to initiating the RRC reconstruction process, the first node sends an RRC reconstruction request message and starts a third timer, and the expiration of the third timer is used to trigger the third wireless signal. Along with the sending of the third wireless signal, the first node starts a fourth timer.

[0247] As a sub-embodiment of the above embodiment, expiration of the fourth timer is used to trigger the first node to enter the RRC idle state.

[0248] As an embodiment, the expiration of the second timer is used to trigger reselection of the serving cell.

[0249] As a sub-embodiment of this embodiment, the reselecting a serving cell includes reselecting a relay residing in or connected to a serving cell.

[0250] As a sub-embodiment of this embodiment, the reselection of the serving cell includes cell selection.

[0251] As a sub-embodiment of this embodiment, the reselection of a serving cell includes selecting a serving cell and sending a random access signal by direct transmission.

[0252] As an embodiment, the expiration of the second timer is used to trigger the first node to perform relay selection, and the third message is sent as a response to the relay node being successfully selected.

[0253] As an embodiment, the expiration of the second timer is used to trigger the first node to perform cell selection, and the third message is sent as a response to the successful selection of the cell.

[0254] As a sub-embodiment of the above embodiment, in response to a successful cell selection, a third timer is started, and expiration of the third timer is used to trigger the first node to enter an RRC idle state.

[0255] As a sub-embodiment of the above embodiment, the relay selection is a part of the cell selection.

[0256] As an embodiment, the sentence when the transmission method to the first serving cell is through relay transmission means: using L2 U2N relay.

[0257] As an embodiment, the sentence when the transmission method to the first service cell is through relay transmission means: a suitable relay is selected.

[0258] As an embodiment, the sentence when the transmission method to the first service cell is through relay transmission means: a suitable L2 relay is selected.

[0259] As an embodiment, the sentence when the transmission mode to the first serving cell is through relay transmission means: a suitable L2 U2N relay is selected.

[0260] As an embodiment, the sentence when the transmission mode to the first serving cell is through relay transmission means: a suitable L2 U2N relay UE is selected.

[0261] As an embodiment, the sentence when the transmission mode to the first serving cell is through relay transmission means: selecting L2 U2N relay UE to receive at least system information of the first serving cell.

[0262] As an embodiment, the sentence when the transmission mode to the first serving cell is through relay transmission means: selecting L2 U2N relay UE to receive at least a paging message of the first serving cell.

[0263] As an embodiment, the phrase selecting the first serving cell includes performing cell selection and performing relay selection.

[0264] As an embodiment, the phrase selecting a first serving cell includes performing cell selection and finding that the first serving cell is a suitable cell; and / or performing relay selection and finding a suitable relay and the first serving cell is a serving cell of the found relay.

[0265] As a sub-embodiment of this embodiment, the behavior of performing relay selection is or includes performing L2 U2N relay UE selection.

[0266] As a sub-embodiment of this embodiment, the behavior of performing relay selection is or includes performing L2 U2N relay selection.

[0267] As a sub-embodiment of this embodiment, the phrase finding a suitable relay refers to finding a suitable L2U2N relay UE.

[0268] As a sub-embodiment of this embodiment, the sentence that the first service cell is the service cell of the discovered relay means that the first service cell is the service cell of the discovered relay in a non-RRC connected state or the primary cell in an RRC connected state.

[0269] As a sub-embodiment of this embodiment, when the first node selects a suitable L2U2N relay UE through relay selection, the transmission mode between the first node and the service cell of the suitable L2 U2N relay UE, that is, the first service cell, is through relay transmission.

[0270] As a sub-embodiment of this embodiment, when the first node selects a suitable cell, namely, the first serving cell, through cell selection, the transmission mode between the first node and the first serving cell is direct transmission.

[0271] As an example, the phrase transmitting via a relay refers to transmitting using a non-direct path.

[0272] As an example, the phrase direct transmission refers to transmission using a direct path.

[0273] As an embodiment, while the first timer is in a running state, the number of times the second timer can be restarted is configurable.

[0274] As an embodiment, when the first timer is in a running state, the number of times the second timer can be restarted is 1.

[0275] As an embodiment, while the first timer is in a running state, the number of times the second timer can be restarted is greater than 0.

[0276] As an embodiment, the first node initiates the RRC reconstruction process and the first timer starts.

[0277] Example 2

[0278] Embodiment 2 illustrates a schematic diagram of a network architecture according to an embodiment of the present application, as shown in the attached Figure 2 Attached Figure 2The V2X communication architecture under the 5G NR (New Radio), LTE (Long-Term Evolution) and LTE-A (Long-Term Evolution Advanced) system architecture is described. The 5G NR or LTE network architecture may be referred to as 5GS (5G System) / EPS (Evolved Packet System) or some other appropriate terminology.

[0279] The V2X communication architecture of embodiment 2 includes UE (User Equipment) 201, UE 241, NG-RAN (next generation radio access network) 202, 5GC (5G Core Network) / EPC (Evolved Packet Core) 210, HSS (Home Subscriber Server) / UDM (Unified Data Management) 220, ProSe function 250 and ProSe application server 230. The V2X communication architecture can be interconnected with other access networks, but these entities / interfaces are not shown for simplicity. As shown, the V2X communication architecture provides packet switching services, but technicians in the field will easily understand that the various concepts presented throughout this application can be extended to networks that provide circuit switching services or other cellular networks. NG-RAN includes NR Node B (gNB) 203 and other gNBs 204. gNB 203 provides user and control plane protocol termination towards UE 201. gNB 203 can be connected to other gNBs 204 via an Xn interface (e.g., backhaul). The gNB 203 may also be referred to as a base station, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a TRP (transmit receive node), or some other suitable term. The gNB 203 provides an access point to the 5GC / EPC 210 for the UE 201. Examples of UE 201 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop computer, a personal digital assistant (PDA), a satellite radio, non-terrestrial base station communications, satellite mobile communications, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a drone, an aircraft, a narrowband Internet of Things device, a machine type communication device, a land vehicle, an automobile, a wearable device, or any other similarly functional device. The UE 201 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable term. The gNB 203 is connected to the 5GC / EPC 210 via an S1 / NG interface.5GC / EPC210 includes MME (Mobility Management Entity) / AMF (Authentication Management Field) / SMF (Session Management Function) 211, other MME / AMF / SMF214, S-GW (Service Gateway) / UPF (User Plane Function) 212 and P-GW (Packet Data Network Gateway) / UPF213. MME / AMF / SMF211 is the control node that handles the signaling between UE201 and 5GC / EPC210. ​​In general, MME / AMF / SMF211 provides bearer and connection management. All user IP (Internet Protocal) packets are transmitted through S-GW / UPF212, which itself is connected to P-GW / UPF213. P-GW provides UE IP address allocation and other functions. P-GW / UPF213 is connected to Internet service 230. Internet service 230 includes Internet protocol services corresponding to operators, which may specifically include Internet, intranet, IMS (IP Multimedia Subsystem) and packet switching streaming services. The ProSe function 250 is a logical function for network-related behaviors required for Proximity-based Service (ProSe); including DPF (Direct Provisioning Function), Direct Discovery Name Management Function, EPC-level Discovery ProSe Function, etc. The ProSe application server 230 has the functions of storing EPC ProSe user identities, mapping between application layer user identities and EPC ProSe user identities, and allocating ProSe restricted code suffix pools.

[0280] As an embodiment, the UE201 and the UE241 are connected via a PC5 reference point (Reference Point).

[0281] As an embodiment, the ProSe function 250 is connected to the UE 201 and the UE 241 via a PC3 reference point respectively.

[0282] As an embodiment, the ProSe function 250 is connected to the ProSe application server 230 via a PC2 reference point.

[0283] As an embodiment, the ProSe application server 230 is connected to the ProSe application of the UE 201 and the ProSe application of the UE 241 through a PC1 reference point respectively.

[0284] As an embodiment, the third node, the first node and the second node in the present application are NR Node B, UE201 and UE241 respectively.

[0285] As an embodiment, the first node and the second node in the present application are UE201 and UE241 respectively.

[0286] As an embodiment, the third node gNB203 in this application.

[0287] As an embodiment, the wireless link between the UE201 and the UE241 corresponds to the side link (Sidelink, SL) in this application.

[0288] As an embodiment, the wireless link from the UE201 to the NR Node B is an uplink.

[0289] As an embodiment, the wireless link from the NR Node B to UE201 is a downlink.

[0290] As an embodiment, the UE 201 supports relay transmission.

[0291] As an embodiment, the UE 241 supports relay transmission.

[0292] As an embodiment, the UE 201 is a vehicle including a car.

[0293] As an embodiment, the UE 241 is a vehicle including a car.

[0294] As an embodiment, the gNB203 is a macrocellular base station.

[0295] As an embodiment, the gNB203 is a micro cell base station.

[0296] As an embodiment, the gNB203 is a picoCell base station.

[0297] As an embodiment, the gNB203 is a flying platform device.

[0298] As an embodiment, the gNB203 is a satellite device.

[0299] Example 3

[0300] Embodiment 3 shows a schematic diagram of an embodiment of a wireless protocol architecture of a user plane and a control plane according to the present application, as shown in the attached Figure 3 shown. Figure 3 is a schematic diagram illustrating an embodiment of a radio protocol architecture for a user plane 350 and a control plane 300, Figure 3The radio protocol architecture of the control plane 300 for a first node (UE, satellite or aircraft in gNB or NTN) and a second node (satellite or aircraft in gNB, UE or NTN), or between two UEs is shown in three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowest layer and implements various PHY (physical layer) signal processing functions. The L1 layer will be referred to as PHY301 in this article. Layer 2 (L2 layer) 305 is above PHY301 and is responsible for the link between the first node and the second node and the two UEs through PHY301. The L2 layer 305 includes a MAC (Medium Access Control) sublayer 302, an RLC (Radio Link Control) sublayer 303, and a PDCP (Packet Data Convergence Protocol) sublayer 304, which terminate at the second node. The PDCP sublayer 304 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 304 also provides security by encrypting data packets, and provides support for inter-zone mobility of the first node between the second node. The RLC sublayer 303 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to HARQ. The MAC sublayer 302 provides multiplexing between logical and transport channels. The MAC sublayer 302 is also responsible for allocating various radio resources (e.g., resource blocks) in a cell between the first nodes. The MAC sublayer 302 is also responsible for HARQ operations. The RRC (Radio Resource Control) sublayer 306 in layer 3 (L3 layer) in the control plane 300 is responsible for obtaining radio resources (i.e., radio bearers) and configuring the lower layer using RRC signaling between the second node and the first node. The PC5-S (PC5 Signaling Protocol) sublayer 307 is responsible for processing the signaling protocol of the PC5 interface. The radio protocol architecture of the user plane 350 includes Layer 1 (L1 layer) and Layer 2 (L2 layer). The radio protocol architecture for the first node and the second node in the user plane 350 is substantially the same as the corresponding layers and sublayers in the control plane 300 for the physical layer 351, the PDCP sublayer 354 in the L2 layer 355, the RLC sublayer 353 in the L2 layer 355, and the MAC sublayer 352 in the L2 layer 355, but the PDCP sublayer 354 also provides header compression for upper layer data packets to reduce radio transmission overhead.The L2 layer 355 in the user plane 350 also includes a SDAP (Service Data Adaptation Protocol) sublayer 356, which is responsible for mapping between QoS flows and data radio bearers (DRBs) to support the diversity of services. Although not shown, the first node may have several upper layers above the L2 layer 355. In addition, it also includes a network layer (e.g., an IP layer) terminated at the P-GW on the network side and an application layer terminated at the other end of the connection (e.g., a remote UE, a server, etc.). For UEs involved in relay services, their control plane may also include an adaptation sublayer AP308, and their user plane may also include an adaptation sublayer AP358. The introduction of the adaptation layer helps lower layers, such as the MAC layer, such as the RLC layer, to multiplex and / or distinguish data from multiple source UEs. In addition, the adaptation sublayers AP308 and AP358 may also be used as sublayers within PDCP304 and PDCP354, respectively. RRC306 can be used to process RRC signaling of the Uu interface and signaling of the PC5 interface.

[0301] As an example, Figure 3 The wireless protocol architecture in is applicable to the first node in this application.

[0302] As an example, Figure 3 The wireless protocol architecture in is applicable to the second node in this application.

[0303] As an embodiment, the first message in the present application is generated in RRC306.

[0304] As an embodiment, the third message in the present application is generated in RRC306.

[0305] As an embodiment, the second message in the present application is generated in RRC306 or PC5-S307.

[0306] As an embodiment, the fourth message in the present application is generated in RRC306.

[0307] As an embodiment, the message 4a in the present application is generated in RRC306.

[0308] As an embodiment, the 3a message in the present application is generated in RRC306.

[0309] As an embodiment, the first protocol layer control PDU in the present application is generated in AP308 or AP358.

[0310] As an embodiment, the first wireless signal in the present application is generated by PHY301 or PHY351.

[0311] As an embodiment, the second wireless signal in the present application is generated by PHY301 or PHY351.

[0312] As an embodiment, the third wireless signal in the present application is generated by PHY301 or PHY351.

[0313] As an embodiment, the fourth wireless signal in the present application is generated by PHY301 or PHY351.

[0314] As an embodiment, the first discovery signal in the present application is generated by PHY301 or PHY351.

[0315] Example 4

[0316] Embodiment 4 shows a schematic diagram of a first communication device and a second communication device according to the present application, as shown in the attached figure. Figure 4 shown. Figure 4 is a block diagram of a first communication device 450 and a second communication device 410 communicating with each other in an access network.

[0317] The first communication device 450 includes a controller / processor 459, a memory 460, a data source 467, a transmit processor 468, a receive processor 456, a multi-antenna transmit processor 457, a multi-antenna receive processor 458, a transmitter / receiver 454 and an antenna 452.

[0318] The second communication device 410 includes a controller / processor 475 , a memory 476 , a receive processor 470 , a transmit processor 416 , a multi-antenna receive processor 472 , a multi-antenna transmit processor 471 , a transmitter / receiver 418 and an antenna 420 .

[0319] In transmission from the second communication device 410 to the first communication device 450, at the second communication device 410, upper layer data packets from the core network are provided to the controller / processor 475. The controller / processor 475 implements the functionality of the L2 layer. In transmission from the second communication device 410 to the first communication device 450, the controller / processor 475 provides header compression, encryption, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation to the first communication device 450 based on various priority metrics. The controller / processor 475 is also responsible for retransmission of lost packets and signaling to the first communication device 450. The transmit processor 416 and the multi-antenna transmit processor 471 implement various signal processing functions for the L1 layer (i.e., the physical layer). The transmit processor 416 implements coding and interleaving to facilitate forward error correction (FEC) at the second communication device 410, as well as mapping of signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The multi-antenna transmit processor 471 performs digital spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing on the coded and modulated symbols to generate one or more spatial streams. The transmit processor 416 then maps each spatial stream to a subcarrier, multiplexes it with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then uses an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain multi-carrier symbol stream. The multi-antenna transmit processor 471 then performs a transmit analog precoding / beamforming operation on the time-domain multi-carrier symbol stream. Each transmitter 418 converts the baseband multi-carrier symbol stream provided by the multi-antenna transmit processor 471 into a radio frequency stream, and then provides it to a different antenna 420.

[0320] In the transmission from the second communication device 410 to the first communication device 450, at the first communication device 450, each receiver 454 receives a signal through its corresponding antenna 452. Each receiver 454 recovers the information modulated onto the RF carrier and converts the RF stream into a baseband multi-carrier symbol stream and provides it to the receiving processor 456. The receiving processor 456 and the multi-antenna receiving processor 458 implement various signal processing functions of the L1 layer. The multi-antenna receiving processor 458 performs a receiving analog precoding / beamforming operation on the baseband multi-carrier symbol stream from the receiver 454. The receiving processor 456 uses a fast Fourier transform (FFT) to convert the baseband multi-carrier symbol stream after the receiving analog precoding / beamforming operation from the time domain to the frequency domain. In the frequency domain, the physical layer data signal and the reference signal are demultiplexed by the receiving processor 456, wherein the reference signal will be used for channel estimation, and the data signal is recovered after multi-antenna detection in the multi-antenna receiving processor 458 to any spatial stream destined for the first communication device 450. The symbols on each spatial stream are demodulated and recovered in the receiving processor 456, and soft decisions are generated. The receiving processor 456 then decodes and deinterleaves the soft decisions to recover the upper layer data and control signals transmitted by the second communication device 410 on the physical channel. The upper layer data and control signals are then provided to the controller / processor 459. The controller / processor 459 implements the functions of the L2 layer. The controller / processor 459 may be associated with a memory 460 that stores program codes and data. The memory 460 may be referred to as a computer-readable medium. In the transmission from the second communication device 410 to the second communication device 450, the controller / processor 459 provides multiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover the upper layer data packets from the core network. The upper layer data packets are then provided to all protocol layers above the L2 layer. Various control signals may also be provided to L3 for L3 processing.

[0321] In the transmission from the first communication device 450 to the second communication device 410, at the first communication device 450, a data source 467 is used to provide upper layer data packets to the controller / processor 459. The data source 467 represents all protocol layers above the L2 layer. Similar to the transmission function at the second communication device 410 described in the transmission from the second communication device 410 to the first communication device 450, the controller / processor 459 implements header compression, encryption, packet segmentation and reordering, and multiplexing between logical and transport channels based on radio resource allocation, and implements L2 layer functions for user plane and control plane. The controller / processor 459 is also responsible for the retransmission of lost packets and signaling to the second communication device 410. The transmit processor 468 performs modulation mapping and channel coding processing, and the multi-antenna transmit processor 457 performs digital multi-antenna spatial precoding, including codebook-based precoding and non-codebook-based precoding, and beamforming processing. Then, the transmit processor 468 modulates the generated spatial stream into a multi-carrier / single-carrier symbol stream, which is then provided to different antennas 452 via the transmitter 454 after analog precoding / beamforming operations in the multi-antenna transmit processor 457. Each transmitter 454 first converts the baseband symbol stream provided by the multi-antenna transmit processor 457 into a radio frequency symbol stream, and then provides it to the antenna 452.

[0322] In the transmission from the first communication device 450 to the second communication device 410, the function at the second communication device 410 is similar to the reception function at the first communication device 450 described in the transmission from the second communication device 410 to the first communication device 450. Each receiver 418 receives a radio frequency signal through its corresponding antenna 420, converts the received radio frequency signal into a baseband signal, and provides the baseband signal to the multi-antenna reception processor 472 and the reception processor 470. The reception processor 470 and the multi-antenna reception processor 472 jointly implement the functions of the L1 layer. The controller / processor 475 implements the L2 layer functions. The controller / processor 475 can be associated with a memory 476 storing program codes and data. The memory 476 can be referred to as a computer-readable medium. In the transmission from the first communication device 450 to the second communication device 410, the controller / processor 475 provides multiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover the upper layer data packets from the UE 450. Upper layer packets from controller / processor 475 may be provided to the core network.

[0323] As an embodiment, the first communication device 450 apparatus includes: at least one processor and at least one memory, the at least one memory including computer program code; the at least one memory and the computer program code are configured to be used together with the at least one processor, and the first communication device 450 apparatus at least: starts a first timer; selects a first service cell; sends a first wireless signal, the first wireless signal includes a first message, the first message is used to request RRC reconstruction; starts a second timer along with sending the first message; operates the first timer according to a transmission method at least to the first service cell; sends a third wireless signal, the third wireless signal includes a third message, the third message is used to request an RRC connection; wherein the expiration of the first timer is used to trigger the first node to enter an RRC idle state; the behavior of operating the first timer according to the transmission method at least to the first service cell includes: when the transmission method to the first service cell is via relay transmission, as a response to selecting the first service cell, stops the first timer; when the transmission method to the first service cell is direct transmission, continues to run the first timer after the behavior selects the first service cell.

[0324] As an embodiment, the first communication device 450 includes: a memory storing a computer-readable instruction program, the computer-readable instruction program generates actions when executed by at least one processor, the actions including: starting a first timer; selecting a first service cell; sending a first wireless signal, the first wireless signal including a first message, the first message being used to request RRC reconstruction; starting a second timer along with sending the first message; operating the first timer according to a transmission method at least to the first service cell; sending a third wireless signal, the third wireless signal including a third message, the third message being used to request an RRC connection; wherein expiration of the first timer is used to trigger the first node to enter an RRC idle state; the behavior of operating the first timer according to a transmission method at least to the first service cell includes: when the transmission method to the first service cell is via relay transmission, stopping the first timer as a response to selecting the first service cell; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0325] As an embodiment, the first communication device 450 corresponds to the first node in this application.

[0326] As an embodiment, the second communication device 450 corresponds to the second node in this application.

[0327] As an embodiment, the second communication device 410 corresponds to the third node in this application.

[0328] As an embodiment, the first communication device 450 is a UE.

[0329] As an embodiment, the first communication device 450 is a vehicle-mounted terminal.

[0330] As an embodiment, the first communication device 450 is a relay.

[0331] As an embodiment, the second communication device 410 is a base station.

[0332] As an embodiment, the first communication device 410 is an access point.

[0333] As an embodiment, the receiver 456 (including the antenna 460), the receiving processor 452 and the controller / processor 490 are used to receive the second wireless signal in the present application.

[0334] As an embodiment, the receiver 456 (including the antenna 460 ), the receiving processor 452 and the controller / processor 490 are used to receive the fourth wireless signal in the present application.

[0335] As an embodiment, the receiver 456 (including the antenna 460 ), the receiving processor 452 and the controller / processor 490 are used to receive the first discovery signal in the present application.

[0336] As an embodiment, the transmitter 456 (including the antenna 460), the transmission processor 455 and the controller / processor 490 are used to send the first wireless signal in the present application.

[0337] As an embodiment, the transmitter 456 (including the antenna 460), the transmission processor 455 and the controller / processor 490 are used to send the third wireless signal in the present application.

[0338] Example 5

[0339] Embodiment 5 illustrates a wireless signal transmission flow chart according to an embodiment of the present application, as shown in the attached Figure 5 Attached Figure 5 In the example, U01 corresponds to the first node of the present application. It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present application, wherein the steps in F51, F52, and F53 are optional.

[0340] for First node U01, receiving a first discovery signal in step S5101; sending a first wireless signal in step S5102; receiving a second wireless signal in step S5103; sending a third wireless signal in step S5104; and receiving a fourth wireless signal in step S5105.

[0341] for Second node U02 , sending a first discovery signal in step S5201; receiving a first wireless signal in step S5202; and sending a second wireless signal in step S5203.

[0342] for The third node U03 , receiving a third wireless signal in step S5301; and sending a fourth wireless signal in step S5302.

[0343] In embodiment 5, the first node U01 starts a first timer; selects a first serving cell; the first wireless signal includes a first message, the first message is used to request RRC reestablishment; along with sending the first message, a second timer is started; the first timer is operated according to a transmission mode at least to the first serving cell; the third wireless signal includes a third message, the third message is used to request RRC connection;

[0344] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission method to at least the first service cell, including: when the transmission method to the first service cell is through relay transmission, stopping the first timer in response to selecting the first service cell; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0345] As an embodiment, the first node U01 is a remote UE, the second node U02 is a relay, and the third node U03 is the first serving cell.

[0346] As an embodiment, the first node U01 is a remote UE, the second node U02 is a relay selected by the first node U01, and the third node U03 is a candidate cell of the first node U01.

[0347] As an embodiment, the first node U01 is a remote UE, the second node U02 is a relay, and the third node U03 is a base station.

[0348] As an embodiment, the first node U01 is a remote UE.

[0349] As an embodiment, the second node U02 is a UE.

[0350] As an embodiment, the third node U03 is a service cell of the first node U01.

[0351] As an embodiment, the third node U03 is the first service cell.

[0352] As an embodiment, the third node U03 is the Pcell of the first node U01.

[0353] As an embodiment, the third node U03 is the SpCell of the first node U01.

[0354] As an embodiment, the third node U03 is the MCG (Master Cell Group) of the first node U01.

[0355] As an embodiment, the communication interface between the first node U01 and the second node U02 is PC5.

[0356] As an embodiment, a secondary link is used for communication between the first node U01 and the second node U02.

[0357] As an embodiment, the communication interface between the first node U01 and the third node U03 is Uu.

[0358] As an embodiment, the communication interface between the second node U02 and the third node U03 is Uu.

[0359] As an embodiment, the first node U01 communicates with the second node U02 using a secondary link.

[0360] As an embodiment, the second node U02 communicates with the third node U03 using a main link.

[0361] As an embodiment, the first wireless signal is a physical layer signal.

[0362] As an embodiment, the meaning of the sentence “the first wireless signal includes a first message” includes: the first wireless signal carries the first message.

[0363] As an embodiment, the meaning of the sentence “the first wireless signal includes a first message” includes: the first wireless signal carries the first message.

[0364] As an embodiment, the sentence “the second wireless signal includes a second message” means: the second wireless signal carries the second message.

[0365] As an embodiment, the meaning of the sentence “the first wireless signal includes the second message” includes: the second wireless signal carries the second message.

[0366] As an embodiment, the meaning of the sentence that the third wireless signal includes the third message includes: the third wireless signal carries the third message.

[0367] As an embodiment, the meaning of the sentence that the third wireless signal includes the third message includes: the third wireless signal carries the third message.

[0368] As an embodiment, the meaning of the sentence that the fourth wireless signal includes the fourth message includes: the fourth wireless signal carries the fourth message.

[0369] As an embodiment, the meaning of the sentence that the fourth wireless signal includes the fourth message includes: the fourth wireless signal carries the fourth message.

[0370] As an embodiment, the first wireless signal includes a first PDCP PDU, and the first PDCP PDU includes the first message; the first PDCP PDU uses encryption.

[0371] As an embodiment, the first PDCP PDU uses integrity protection.

[0372] As an embodiment, the first discovery signal is a physical layer signal.

[0373] As an embodiment, the physical channel occupied by the first discovery signal includes PSSCH.

[0374] As an embodiment, the physical channel occupied by the first discovery signal includes PSCCH.

[0375] As an embodiment, the physical channel occupied by the first discovery signal includes a physical channel of a secondary link.

[0376] As an embodiment, the first discovery signal includes or carries a first discovery message.

[0377] As a sub-embodiment of this embodiment, the first discovery message is used for discovery.

[0378] As a sub-embodiment of this embodiment, the first discovery message is used to be discovered.

[0379] As a sub-embodiment of this embodiment, the first discovery message includes a discovery message (discoverymessage).

[0380] As a sub-embodiment of this embodiment, the first discovery message uses discovery mode A.

[0381] As a sub-embodiment of this embodiment, the first discovery message uses discovery mode B.

[0382] As a sub-embodiment of this embodiment, the first discovery message is transmitted using SRB4.

[0383] As a sub-embodiment of this embodiment, the first discovery message includes a PLMN (Public Land Mobile Network) identity.

[0384] As a sub-embodiment of this embodiment, the first discovery message includes the identity of the first serving cell.

[0385] As a sub-embodiment of this embodiment, the first discovery message includes a relay service code.

[0386] As a sub-embodiment of this embodiment, the first discovery message includes a first identity and a second identity.

[0387] As a sub-embodiment of this embodiment, the second identity is used to identify the second node U02.

[0388] As a sub-embodiment of this embodiment, the first identity is used to identify the first node U01.

[0389] As a sub-embodiment of this embodiment, the first identity is used to identify a first group, and the first node U01 belongs to the first group.

[0390] As an embodiment, the second node U02 sends a first system message, and the first system message includes at least part of the bits of SIB1 of the first serving cell.

[0391] As an embodiment, the first node U01 receives the first system message.

[0392] As an embodiment, the first system message includes the identity of the first serving cell.

[0393] As an embodiment, SIB1 of the first serving cell is used to generate the first system message.

[0394] As an embodiment, SIB1 of the first serving cell is used to generate the first discovery message.

[0395] As an embodiment, the first system message is a PC5-RRC message.

[0396] As an embodiment, the first system message is sent via unicast.

[0397] As an embodiment, the first system message is sent by broadcasting.

[0398] As an embodiment, the first system message is sent via multicast.

[0399] As an embodiment, the first system message includes the PLMN identity included in the first discovery message.

[0400] As an embodiment, the PLMN identity included in the first discovery message is used to select the first serving cell.

[0401] As a sub-embodiment of the above embodiment, the PLMN indicated by the first discovery message is a PLMN supported by or allowed to be accessed by the first node U01.

[0402] As a sub-embodiment of the above embodiment, the PLMN indicated by the first discovery message is the HPLMN or EHPLMN (Equivalent Home PLMN) of the first node U01.

[0403] As a sub-embodiment of the above embodiment, when the PLMN indicated by the first discovery message is a PLMN supported by the first node U01, the first node U01 selects the first serving cell.

[0404] As a sub-embodiment of the above embodiment, when the PLMN indicated by the first discovery message is the HPLMN (Home PLMN) of the first node U01, the first node U01 selects the first serving cell.

[0405] As an embodiment, the second node U02 receives the first wireless signal.

[0406] As an embodiment, the second node U02 does not receive the first wireless signal.

[0407] As an embodiment, the first node U01 detects that the first wireless link fails, and the first wireless signal is sent through the first wireless link; in response to detecting the failure of the first wireless link, the first node U01 stops the second timer and performs service cell selection.

[0408] As a sub-embodiment of the above embodiment, the first node U01 monitors the strength of the wireless signal. When it is found that the strength of the wireless signal is lower than a predefined threshold, the first node U01 considers that a wireless link failure is detected.

[0409] As a sub-embodiment of the above embodiment, the first node U01 monitors the strength of the wireless signal on the time-frequency resources occupied by the first wireless link. When it is found that the strength of the wireless signal is lower than a predefined threshold, the first node U01 considers that a wireless link failure is detected.

[0410] As a sub-embodiment of the above embodiment, the first node U01 monitors the discovery message sent by the second node U02, and the discovery message is sent periodically. When the first node U01 fails to detect the discovery message sent by the second node U02, the first node U01 considers that a wireless link failure occurs in the first wireless link.

[0411] As a sub-embodiment of the above embodiment, when the first node U01 fails to detect ACK or NACK for the first wireless signal, the first node U01 considers that a wireless link failure occurs in the first wireless link.

[0412] As a sub-embodiment of the above embodiment, the first wireless link is a secondary link.

[0413] As a sub-embodiment of the above embodiment, the first wireless link is a wireless link between the first node U01 and the second node U02.

[0414] As a sub-embodiment of the above embodiment, the first wireless link is a direct unicast link.

[0415] As a sub-embodiment of the above embodiment, the first node U01 detects that the radio link of the first radio link fails after the first radio signal is sent.

[0416] As a sub-embodiment of the above embodiment, the first node U01 detects the radio link failure of the first radio link before the first radio signal is sent.

[0417] As a sub-embodiment of the above embodiment, the first node U01 detects that the first radio link failure is used to trigger the first node to enter the RRC idle state, and the first node entering the RRC idle state triggers the first node U01 to stop the first timer and the second timer.

[0418] As a sub-embodiment of the above embodiment, the sentence "stop the second timer" includes the following meaning: if the second timer is in a running state, the second timer is stopped.

[0419] As a sub-embodiment of the above embodiment, the sentence "stop the second timer" includes the following meaning: if the second timer is in a stopped state, the stopped state of the second timer is not interfered with.

[0420] As a sub-embodiment of the above embodiment, expiration of the second timer triggers the first node U01 to consider that failure of the first radio link is detected.

[0421] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: executing cell selection to select a suitable cell.

[0422] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: executing cell selection to select an acceptable cell.

[0423] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: performing cell selection according to an S criterion to select a suitable cell.

[0424] As a sub-embodiment of the above embodiment, the behavior of selecting a service cell includes: determining a first service cell as a receiver of the third wireless signal.

[0425] As a sub-embodiment of the above embodiment, the behavior of selecting a service cell includes: determining a first service cell, and attempting to connect to the first service cell by direct transmission.

[0426] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: determining a cell identity of the first serving cell through a SIB1 system message.

[0427] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a first serving cell as a recipient of the third message.

[0428] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: attempting RRC connection reestablishment on the third node U03.

[0429] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: attempting RRC connection reestablishment in a cell other than the first serving cell.

[0430] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: attempting RRC connection reestablishment on the first serving cell.

[0431] As a sub-embodiment of the above embodiment, the behavior of selecting a service cell includes: selecting the first service cell as the service cell, and determining that the transmission mode with the first service cell is direct transmission.

[0432] As a sub-embodiment of the above embodiment, the behavior of selecting a service cell includes: selecting a service cell other than the first service cell as a service cell, and determining that the transmission mode with the selected service cell other than the first service cell is direct transmission.

[0433] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: setting reestablishmentCellId to the identity of the selected serving cell.

[0434] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: using the first serving cell as a target cell for RRC reconstruction of the first node U01.

[0435] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: taking a serving cell other than the first serving cell as a target cell for RRC reconstruction of the first node U01.

[0436] As a sub-embodiment of the above embodiment, the third node U03 is the serving cell selected by the first node U01 after the behavior of selecting a serving cell is performed.

[0437] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a direct transmission method to connect to the selected serving cell.

[0438] As an embodiment, expiration of the second timer triggers the first node U01 to select a service cell.

[0439] As an embodiment, the second wireless signal is a physical layer signal.

[0440] As an embodiment, the second wireless signal is sent via a secondary link.

[0441] As an embodiment, the physical channel occupied by the second wireless signal includes PSSCH.

[0442] As an embodiment, the physical channel occupied by the second wireless signal includes PSCCH.

[0443] As an embodiment, the reception of the second message triggers the first node U01 to stop the first timer.

[0444] As an embodiment, the reception of the second message triggers the first node U01 to stop the second timer.

[0445] As an embodiment, the reception of the second message triggers the first node U01 to enter the RRC IDLE state, and the first node U01 entering the RRC idle state triggers the first node U01 to stop the first timer.

[0446] As an embodiment, the reception of the second message triggers the first node U01 to enter the RRC IDLE state, and the first node U01 entering the RRC idle state triggers the first node U01 to stop the second timer.

[0447] As an embodiment, the RRC connection requested by the third message includes a newly established RRC connection and a re-established RRC connection.

[0448] As an embodiment, the second message triggers the first node U01 to enter the RRC idle state, and the third message is RRCSetupRequest.

[0449] As an embodiment, the second message triggers the first node U01 to enter the RRC idle state, and the third message is RRCConnectionSetupRequest.

[0450] As an embodiment, the second message triggers the first node U01 to perform relay reselection as part of selecting a serving cell, and the third message is RRCReestablishmentRequest.

[0451] As an embodiment, the second message triggers the first node U01 to perform relay reselection as part of selecting a serving cell, and the third message is RRCConnectionReestablishmentRequest.

[0452] As an embodiment, the fourth wireless signal is a physical layer signal.

[0453] As an embodiment, the fourth wireless signal is sent via a secondary link.

[0454] As an embodiment, the physical channel occupied by the fourth wireless signal includes PDSCH (Physical Downlink Shared Channel).

[0455] As an embodiment, the physical channel occupied by the fourth wireless signal includes PDCCH (Physical Downlink Control Channel).

[0456] As an embodiment, the fourth wireless signal and the third wireless signal use the same transmission method, and the transmission method includes relay transmission and direct transmission.

[0457] As an embodiment, the fourth wireless signal and the third wireless signal use different transmission modes, and the transmission modes include relay transmission and direct transmission.

[0458] As an embodiment, the fourth message includes RRCSetup.

[0459] As an embodiment, the fourth message includes RRCRelease.

[0460] As an embodiment, the fourth message includes RRCReject.

[0461] As an embodiment, the fourth message includes RRCReestablishment.

[0462] As an embodiment, the fourth message includes RRConnectionSetup.

[0463] As an embodiment, the fourth message includes RRCConnectionReestablishment.

[0464] As an embodiment, when the third message is RRCReestablishmentRequest, the fourth message includes RRCReestablishment.

[0465] As an embodiment, when the third message is RRCReestablishmentRequest, the fourth message includes RRCReject.

[0466] As an embodiment, when the third message is RRCSetupRequest, the fourth message includes RRCSetup.

[0467] As an embodiment, when the third message is RRCSetupRequest, the fourth message includes RRCRelease.

[0468] As an embodiment, when the third message is RRCSetupRequest, the fourth message includes RRCReject.

[0469] As an embodiment, in response to receiving the fourth message, the first node U01 stops the first timer.

[0470] As an embodiment, in response to receiving the fourth message, the first node U01 stops the second timer.

[0471] As an embodiment, the fourth message triggers the first node U01 to enter the RRC idle state, and in response to entering the RRC idle state, the first node U01 stops the first timer.

[0472] As an embodiment, the fourth message triggers the first node U01 to enter the RRC idle state, and in response to entering the RRC idle state, the first node U01 stops the second timer.

[0473] Example 6

[0474] Embodiment 6 illustrates a wireless signal transmission flow chart according to an embodiment of the present application, as shown in the attached Figure 6 Attached Figure 6 In the example, U11 corresponds to the first node of the present application. It is particularly noted that the order in this example does not limit the signal transmission order and implementation order in the present application; the steps in F61, F62, and F63 are optional; Example 6 is based on Example 5, and the parts required but not described in Example 6 can be found in Example 5.

[0475] for First node U11 , receiving a first discovery signal in step S6101; sending a first wireless signal in step S6102; receiving a second wireless signal in step S6103; sending a third wireless signal in step S6104; and receiving a fourth wireless signal in step S6105.

[0476] for Second node U12 , sending a first discovery signal in step S6201; receiving a first wireless signal in step S6202; and sending a second wireless signal in step S6203.

[0477] for The third node U13 , receive the 3a wireless signal in step S6301; and send the 4a wireless signal in step S6302.

[0478] for Fourth node U14, receiving the third wireless signal in step S6401; sending the 3a wireless signal in step S6402; receiving the 4a wireless signal in step S6403; and sending the fourth wireless signal in step S6404.

[0479] As an embodiment, the second node U12 is a relay of the first node U11.

[0480] As an embodiment, the first node U11 selects a first service cell and determines that the transmission method to the first service cell is through relay transmission.

[0481] As a sub-embodiment of the above embodiment, the relay for the relay transmission is the second node U12.

[0482] As an embodiment, the first node U11 is a remote UE.

[0483] As an embodiment, the first node U12 is a UE.

[0484] As an embodiment, the third node U13 is a serving cell.

[0485] As an embodiment, the third node U13 is a service cell group.

[0486] As an embodiment, the third node U13 is a base station.

[0487] As an embodiment, the third node U13 is a primary serving cell.

[0488] As an embodiment, the third node U13 is the first service cell.

[0489] As an embodiment, the second node U12 resides in the first service cell.

[0490] As an embodiment, there is an RRC connection between the second node U12 and the first serving cell.

[0491] As an embodiment, the second message is used to trigger the first node U11 to perform relay selection or relay reselection.

[0492] As an embodiment, the second message is used to trigger the first node U11 to select a serving cell and a transmission method to the selected serving cell.

[0493] As an embodiment, the second message is used to trigger the first node U11 to select a serving cell.

[0494] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: executing relay selection.

[0495] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: executing relay selection, and the selected relay resides in the first serving cell.

[0496] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: executing relay selection, and the selected relay resides in a serving cell other than the first serving cell.

[0497] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a second node U12, where the second node U12 is a relay of the first node U12, and an RRC connection exists between the second node U12 and the first serving cell.

[0498] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a second node U12, wherein the second node U12 is a relay of the first node U11, and a PCell of the second node U12 is the first serving cell.

[0499] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a serving cell according to a PLMN identity and an identity of the serving cell included in the first discovery message.

[0500] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a serving cell according to a PLMN identity and an identity of the serving cell included in a discovery message sent by a relay node.

[0501] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting a second node U12, and a discovery message (discovery message) sent by the second node U12 includes the identity of the first serving cell.

[0502] As a sub-embodiment of the above embodiment, the behavior of selecting a serving cell includes: selecting to connect to the selected serving cell using a relay transmission method.

[0503] As an embodiment, the fourth node U14 is a UE.

[0504] As an embodiment, the fourth node U14 is a relay.

[0505] As an embodiment, the fourth node U14 is a relay of the first node U11.

[0506] As an embodiment, after receiving the second message, the fourth node U14 is determined as a relay.

[0507] As an embodiment, after receiving the second message, the transmission mode from the first node U11 to the third node U13 is determined to be relay transmission through the fourth node U14.

[0508] As an embodiment, the discovery message sent by the fourth node U14 includes the cell identity of the third node U13.

[0509] As an embodiment, the discovery message sent by the fourth node U14 includes the PLMN identity to which the third node U13 belongs or is indicated.

[0510] As an embodiment, the fourth node U14 resides on the third node U13.

[0511] As an embodiment, the fourth node U14 has an RRC connection with the third node U13.

[0512] As an embodiment, the third node U13 is the first service cell.

[0513] As an embodiment, the third node U13 is a service cell other than the first service cell.

[0514] As an embodiment, the fourth node U14 is a node other than the second node U12.

[0515] As an embodiment, the fourth node U14 belongs to the same group as the second node U12 and the first node U11.

[0516] As an embodiment, the third wireless signal is transmitted via a secondary link.

[0517] As an embodiment, the physical channel occupied by the third wireless signal includes PSSCH.

[0518] As an embodiment, the physical channel occupied by the third wireless signal includes PSCCH.

[0519] As an embodiment, the third message includes a PC5-RRC message.

[0520] As an embodiment, the third message includes a PC5-S message.

[0521] As an embodiment, the third wireless signal is used to generate the 3a-th wireless signal.

[0522] As an embodiment, the third wireless signal is used to trigger the 3a wireless signal.

[0523] As an embodiment, the physical channel occupied by the 3ath wireless signal is PUSCH.

[0524] As an embodiment, the 3ath wireless signal is an uplink wireless signal.

[0525] As an embodiment, the 3ath wireless signal includes a 3ath message.

[0526] As a sub-embodiment of the above embodiment, the 3a message is the same as the third message.

[0527] As a sub-embodiment of the above embodiment, the 3a message is different from the third message.

[0528] As a sub-embodiment of the above embodiment, the 3a message is different from the third message, the 3a message is an RRC message, and the third message is a PC5-S message.

[0529] As a sub-embodiment of the above embodiment, the 3a message is different from the third message, the 3a message is an RRC message, and the third message is a PC5-RRC message.

[0530] As a sub-embodiment of the above embodiment, the 3a message is different from the third message, and the 3a message is generated by the domain included in the third message.

[0531] As a sub-embodiment of the above embodiment, the 3a message is different from the third message, and the 3a message does not use encryption or is not encrypted; the third message uses encryption or is encrypted.

[0532] As a sub-embodiment of the above embodiment, the 3a message includes RRCSetupRequest.

[0533] As a sub-embodiment of the above embodiment, the 3a message includes RRCReestablishmentRequest.

[0534] As a sub-embodiment of the above embodiment, the 3a message includes RRCResumeRequest.

[0535] As a sub-embodiment of the above embodiment, the 3a message includes RRCResumeRequest1.

[0536] As a sub-embodiment of the above embodiment, the 3a message is used to request an RRC connection of the first node U11.

[0537] As a sub-embodiment of the above embodiment, the 3a message is used to request an RRC connection between the first node U11 and the third node U13.

[0538] As an embodiment, the physical channel occupied by the 4ath wireless signal is PDSCH.

[0539] As an embodiment, the physical channel occupied by the 4ath wireless signal is PDCCH.

[0540] As an embodiment, the 4ath wireless signal is a downlink wireless signal.

[0541] As an embodiment, the 4ath wireless signal includes a 4ath message.

[0542] As an embodiment, the 3a message triggers the 4a message.

[0543] As an embodiment, the 4a message is used to feed back the 3a message.

[0544] As an embodiment, the 4a message is used to approve or confirm the RRC connection of the first node U11 requested by the 3a message.

[0545] As an embodiment, the message 4a includes RRCSetup.

[0546] As an embodiment, the message 4a includes RRCReestablishment.

[0547] As an embodiment, the message 4a includes RRCReject.

[0548] As an embodiment, the 4a message includes RRCRelease.

[0549] As an embodiment, the fourth message is the same as the 4a message.

[0550] As an embodiment, the 4a message is used to generate the fourth message.

[0551] As an embodiment, the fourth message is used to agree or confirm the request of the third message.

[0552] As an embodiment, the fourth node U14 forwards the 4a message via the fourth wireless signal.

[0553] As an embodiment, the reception of the second message is used to trigger the stopping of the second timer.

[0554] As an embodiment, the reception of the second message is used to trigger the sending of the third wireless signal.

[0555] As an embodiment, the advantage of the above method is that the second timer is terminated in advance, which is conducive to the first node to quickly re-initiate RRC reconstruction, or initiate a request for RRC establishment, saving time and reducing interruptions.

[0556] As an embodiment, the first message is the Nth RRC reconstruction request attempt initiated by the first node U11 while the first timer is running, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; the transmission method of the N RRC reconstruction requests to the first service cell is all through relay transmission.

[0557] As a sub-embodiment of the above embodiment, the third node U13 is the first serving cell.

[0558] As a sub-embodiment of the above embodiment, N is equal to 2.

[0559] As a sub-embodiment of the above embodiment, N is equal to 4.

[0560] As a sub-embodiment of the above embodiment, the N is configurable.

[0561] As a sub-embodiment of the above embodiment, the first message includes RRCReestablishmentRequest, and before sending the first message and during the running period after the first timer starts but before it expires or stops, the first node U11 has sent RRCReestablishmentRequest at least N-1 times.

[0562] As a sub-embodiment of the above embodiment, N-1 RRC reestablishment requests sent before sending the first message are all relayed through the second node U12.

[0563] As a sub-embodiment of the above embodiment, the N-1 RRC reestablishment requests sent before sending the first message are relayed through the second node U12 and at least one node other than the second node U12.

[0564] As a sub-embodiment of the above embodiment, expiration of the second timer is used to trigger the sending of the RRC re-establishment request.

[0565] As a sub-embodiment of the above embodiment, the N RRC reestablishment request attempts are respectively directed to N different serving cells.

[0566] As a sub-embodiment of the above embodiment, the shortMAC-I included in the RRC reestablishment request messages of any two of the N RRC reestablishment request attempts is different.

[0567] As an embodiment, the second timer includes T300.

[0568] As an embodiment, the second timer includes T319.

[0569] Example 7

[0570] Embodiment 7 illustrates a schematic diagram of a candidate node group according to an embodiment of the present application, as shown in the attached figure. Figure 7 shown.

[0571] As an example, Figure 7 The first node in corresponds to the first node in this application.

[0572] As an example, Figure 7 The third node corresponds to the first service cell of this application.

[0573] As an example, Figure 7 The second node and the fourth node in belong to the first candidate node group, and the second node and the fourth node are candidate relay nodes respectively.

[0574] As an embodiment, the first candidate node group includes candidate relay nodes.

[0575] As an embodiment, the first node determines a transmission mode from the first node to the third node according to an internal algorithm, and the transmission mode includes one of relay transmission and direct transmission.

[0576] As an embodiment, the first candidate node group includes K candidate nodes, the second node and the fourth node are two of them, and K is a positive integer greater than 1.

[0577] As an embodiment, a node having the same group identity as the first node is determined as a candidate relay node.

[0578] As an embodiment, a node that has the same group identity as the first node and sends a discovery message and the sent discovery message indicates that a node can receive a relay service is determined as a candidate relay node.

[0579] As an embodiment, a node that has the same group identity as the first node and sends a discovery message, and the sent discovery message includes a relay service code is determined as a candidate relay node.

[0580] As an embodiment, the service cell of the first node configures the first candidate node group.

[0581] As an embodiment, the first node configures the first candidate node group in a serving cell before a radio link failure occurs.

[0582] As an embodiment, the service cell to which the first node is connected before sending the first wireless signal configures the first candidate node group.

[0583] As an embodiment, the first node configures the first candidate node group for the serving cell for which the first node attempts RRC reconstruction.

[0584] As an embodiment, the serving cell of the first node configures the first candidate node group through an RRCReconfiguration message.

[0585] As an embodiment, the serving cell of the first node configures the first candidate node group through an RRCRelease message.

[0586] As an embodiment, the nodes included in the first candidate node group are all UEs.

[0587] As an embodiment, the UEs included in the first candidate node group all reside in the first serving cell.

[0588] As an embodiment, any node included in the first candidate node group resides in the first serving cell, or establishes an RRC connection with the first serving cell.

[0589] As an embodiment, whether the target recipient of the third wireless signal belongs to the first candidate node group is used to determine whether the third message is used to request to establish an RRC connection or to re-establish an RRC connection.

[0590] As an embodiment, when the target recipient of the third wireless signal belongs to the first candidate node group, the third message is RRCReestablishmentRequest.

[0591] As a sub-embodiment of the above embodiment, the third wireless signal is sent through a side link, the third wireless signal includes a third MAC PDU, the third MAC PDU includes a third MAC sub-PDU, the third MAC sub-PDU includes a third MAC sub-header, and the DST field of the third MAC sub-header indicates the target recipient of the third wireless signal.

[0592] As an embodiment, when the target recipient of the third wireless signal belongs to the first candidate node group, the third message is RRCSetupRequest.

[0593] As a sub-embodiment of the above embodiment, the third wireless signal is sent through the main link, and the target receiver of the third wireless signal does not belong to the first candidate node group.

[0594] As a sub-embodiment of the above embodiment, the third wireless signal is sent through a PUSCH channel, and a target receiver of the third wireless signal does not belong to the first candidate node group.

[0595] As a sub-embodiment of the above embodiment, the third wireless signal includes a third MAC PDU, the third MAC PDU includes a third MAC sub-PDU, the third MAC sub-PDU includes a third MAC sub-header, and the DST field of the third MAC sub-header indicates the target recipient of the third wireless signal.

[0596] As an embodiment, the first node establishes a direct link with at least one node in the first candidate node group.

[0597] As an embodiment, the first node establishes direct links with more than one node in the first candidate node group.

[0598] As an embodiment, the first node establishes direct links with all nodes in the first candidate node group.

[0599] As an embodiment, the direct link comprises a direct unicast link.

[0600] As an embodiment, the first message is the Nth RRC reconstruction request attempt initiated by the first node in one operation of the first timer, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; the transmission method of the N RRC reconstruction requests to the first service cell is all through relay transmission, and the relay used for the relay transmission belongs to the first candidate node group.

[0601] As an embodiment, any candidate node in the first candidate node group is associated with a priority, and the priority is used to determine the relay in the first candidate node group.

[0602] As an embodiment, any candidate node in the first candidate node group sends information indicating load strength, and the load strength is used to determine a relay from within the first candidate node group.

[0603] Example 8

[0604] Embodiment 8 illustrates a schematic diagram of a second message according to an embodiment of the present application being used to determine that the first message is not successfully distributed, as shown in the attached Figure 8 shown.

[0605] As an embodiment, the second message includes a PC5-RRC message.

[0606] As an embodiment, the second message includes a PC5-S message.

[0607] As an embodiment, the second message indicates that an interface or link transmitting the first message fails.

[0608] As an embodiment, the second message indicates a radio link failure.

[0609] As an embodiment, the second message indicates a switching failure.

[0610] As an embodiment, the second message indicates an access failure.

[0611] As an embodiment, the second message indicates that access is blocked.

[0612] As an embodiment, the second message indicates that access is denied.

[0613] As an embodiment, the second message indicates that the RRC connection is released.

[0614] As an embodiment, the second message indicates that the RRC connection is suspended.

[0615] As an embodiment, the second message indicates an unknown error.

[0616] As an embodiment, the second message indicates that the first message was not successfully distributed.

[0617] As an embodiment, the second message indicates that the first serving cell is unsuitable.

[0618] As an embodiment, the second message indicates that the compatibility check fails.

[0619] As an embodiment, the second message indicates that the radio bearer used to send the first message is released.

[0620] As an embodiment, the second message indicates a relay failure.

[0621] As an embodiment, the second message indicates the release of a direct unicast link.

[0622] As an embodiment, the second message indicates releasing the PC5 link.

[0623] As an embodiment, the second message includes direct link modification.

[0624] As an embodiment, the second message includes a Direct link release request.

[0625] As an embodiment, the second message includes Direct link failure.

[0626] As an embodiment, the second message includes a Direct link failure indication.

[0627] As an embodiment, the second message includes direct link failure information.

[0628] As an embodiment, the second message includes a Direct link failure report.

[0629] As an embodiment, the second message indicates that a fourth timer has expired, and the expiration of the fourth timer may determine that the first message has not been correctly distributed.

[0630] As an embodiment, in response to receiving the second message, the first node resends the first message, and in response to sending the first message, the second timer is restarted.

[0631] As an embodiment, in response to receiving the second message, the first node sends the i-th wireless signal through the secondary link, and the i-th wireless signal includes an RRC reconstruction request message. In response to sending the RRC reconstruction request message, the second timer is restarted.

[0632] As an embodiment, in response to receiving the second message, the first node reselects a relay node and sends the i-th wireless signal via the secondary link, the i-th wireless signal including an RRC reconstruction request message, and in response to sending the RRC reconstruction request message, the second timer is restarted.

[0633] As an embodiment, the second message is sent via unicast.

[0634] Example 9

[0635] Embodiment 9 illustrates a schematic diagram of a second message according to an embodiment of the present application being used to trigger the reselection of a relay, as shown in the attached figure. Fig. 9 shown.

[0636] As an embodiment, the second message indicates that a sender of the second message has switched.

[0637] As a sub-embodiment of the above embodiment, the sender of the second message is a relay of the first node.

[0638] As a sub-embodiment of the above embodiment, the sender of the second message is the sender of the second wireless signal.

[0639] As a sub-embodiment of the above embodiment, the sender of the second message is the second node.

[0640] As a sub-embodiment of the above embodiment, the sender of the second message is a node in the first candidate node group in Embodiment 7.

[0641] As a sub-embodiment of the above embodiment, the sender of the second message resides in the first serving cell.

[0642] As a sub-embodiment of the above embodiment, there is an RRC connection between the sender of the second message and the first serving cell.

[0643] As a sub-embodiment of the above embodiment, the PCell of the sender of the second message is the first serving cell.

[0644] As a sub-embodiment of the above embodiment, the sender of the second message is the receiver of the first wireless signal.

[0645] As a sub-embodiment of the above embodiment, the second message indicates that a handover occurs to the sender of the second message.

[0646] As a sub-embodiment of the above embodiment, the second message indicates that the switching occurring to the sender of the second message is a conditional switching, and the conditional switching is achieved by conditional reconfiguration.

[0647] As a sub-embodiment of the above embodiment, the second message indicates that a sender of the second message has switched, triggering the first node to perform relay reselection or reselect a relay.

[0648] As an embodiment, the second message indicates that a serving cell of a sender of the second message has changed.

[0649] As a sub-embodiment of the above embodiment, the sender of the second message is a relay of the first node.

[0650] As a sub-embodiment of the above embodiment, the sender of the second message is the sender of the second wireless signal.

[0651] As a sub-embodiment of the above embodiment, the sender of the second message is the second node.

[0652] As a sub-embodiment of the above embodiment, the sender of the second message is a node in the first candidate node group in Embodiment 7.

[0653] As a sub-embodiment of the above embodiment, the sender of the second message resides in the first serving cell.

[0654] As a sub-embodiment of the above embodiment, there is an RRC connection between the sender of the second message and the first serving cell.

[0655] As a sub-embodiment of the above embodiment, the PCell of the sender of the second message is the first serving cell.

[0656] As a sub-embodiment of the above embodiment, the sender of the second message is the receiver of the first wireless signal.

[0657] As a sub-embodiment of the above embodiment, the second message indicates that a PCell of a sender of the second message changes.

[0658] As a sub-embodiment of the above embodiment, the second message indicates that the MCG of the sender of the second message has changed.

[0659] As a sub-embodiment of the above embodiment, the second message indicates that the sender of the second message has executed reconfigwithSync.

[0660] As a sub-embodiment of the above embodiment, the second message indicates that a cell where a sender of the second message resides has changed.

[0661] As a sub-embodiment of the above embodiment, the second message indicates that the sender of the second message has performed cell reselection.

[0662] As a sub-embodiment of the above embodiment, the second message indicates that a serving cell of a sender of the second message has changed, triggering the first node to perform relay reselection or reselect a relay.

[0663] As an embodiment, the time-frequency resources occupied by the second message are used to indicate that the sender of the second message is switching.

[0664] As a sub-embodiment of the above embodiment, the second message includes a discovery message.

[0665] As a sub-embodiment of the above embodiment, the second message occupies resources in the exceptional pool.

[0666] As a sub-embodiment of the above embodiment, the time-frequency resources occupied by the second message can only be used when switching is performed.

[0667] As a sub-embodiment of the above embodiment, the time-frequency resources occupied by the second message can only be used when performing random access.

[0668] As a sub-embodiment of the above embodiment, the second message indicates that a sender of the second message has switched, triggering the first node to perform relay reselection or reselect a relay.

[0669] As an embodiment, the second message includes a discovery message, the second message indicates a cell where the sender of the second message resides, and the cell where the sender of the second message indicated by the second message resides changes, triggering the first node to perform relay reselection or reselect relay.

[0670] As an embodiment, the second message includes a discovery message, the second message indicates the current serving cell of the sender of the second message, and the current serving cell of the sender of the second message indicated by the second message changes, triggering the first node to perform relay reselection or reselect relay.

[0671] As an embodiment, the first node selects a relay according to the strength of signals sent by different relay nodes.

[0672] As an embodiment, the first node determines the identity of the serving cell based on the signals sent by different relay nodes.

[0673] As an embodiment, the first node is based on the priorities of different relay nodes.

[0674] As an embodiment, the first node is based on whether different relay nodes belong to the same group.

[0675] As an embodiment, the first node is based on whether different relay nodes belong to the first candidate node group.

[0676] As an embodiment, the first node reselects a relay according to an internal algorithm.

[0677] As an embodiment, after the relay selects or reselects the relay, the relay selected by the first node is the sender of the second message.

[0678] As an embodiment, after the relay selects or reselects the relay, the relay selected by the first node is a node other than the sender of the second message.

[0679] As an embodiment, after the relay selects or reselects the relay, the relay selected by the first node is the fourth node in Embodiment 6.

[0680] As an embodiment, the reselection of relay includes at least one of cell selection or relay selection.

[0681] Example 10

[0682] Embodiment 10 illustrates a structural block diagram of a processing device used in a first node according to an embodiment of the present application; Fig.10 As shown in the attached Fig.10 In the embodiment 10, the processing device 1000 in the first node includes a first receiver 1001 and a first transmitter 1002.

[0683] The first transmitter 1002 starts a first timer; selects a first serving cell; sends a first wireless signal, wherein the first wireless signal includes a first message, wherein the first message is used to request RRC reestablishment; starts a second timer along with sending the first message; operates the first timer according to a transmission mode at least to the first serving cell; sends a third wireless signal, wherein the third wireless signal includes a third message, wherein the third message is used to request RRC connection;

[0684] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission method to at least the first service cell, including: when the transmission method to the first service cell is through relay transmission, stopping the first timer in response to selecting the first service cell; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after the behavior selects the first service cell.

[0685] As an embodiment, the first transmitter 1002 starts a first timer; selects a first serving cell; sends a first wireless signal, wherein the first wireless signal includes a first message, and the first message is used to request RRC reestablishment; starts a second timer along with sending the first message; operates the first timer according to a transmission mode at least to the first serving cell; sends a third wireless signal, wherein the third wireless signal includes a third message, and the third message is used to request an RRC connection;

[0686] Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the behavior operates the first timer according to the transmission method to at least the first service cell, including: when the transmission method to the first service cell is through relay transmission, continue to run the first timer after the behavior selects the first service cell; when the transmission method to the first service cell is direct transmission, stop the first timer in response to selecting the first service cell.

[0687] As an embodiment, the first receiver 1001 receives a second wireless signal, where the second wireless signal includes a second message, and the second message is used to determine that the first message is not successfully distributed.

[0688] As an embodiment, the second message is used to trigger the first transmitter 1002 to stop the first timer and the second timer, and the first node enters the RRC idle state;

[0689] The third wireless signal is sent when the first node enters the RRC idle state; and the third message is used to request to establish an RRC connection.

[0690] As an embodiment, the second message is used to trigger the first transmitter 1002 to restart the second timer and send the third message; the third message is used to request RRC reconstruction.

[0691] As an embodiment, the first receiver 1001 receives a fourth wireless signal, where the fourth wireless signal includes a fourth message, and the fourth message is used to feed back the third message;

[0692] The fourth message is used to trigger, at the first transmitter 1002, to stop the first timer and the second timer.

[0693] As an embodiment, the second message is used to trigger reselection of a relay.

[0694] As an embodiment, the first receiver 1001 detects that the first wireless link fails, and the first wireless signal is sent through the first wireless link;

[0695] In response to detecting the failure of the first radio link, the first receiver 1001 stops the second timer and performs serving cell selection.

[0696] As an embodiment, the first receiver 1001 receives a first discovery signal, where the first discovery signal is used to indicate a first service cell; the behavior of selecting the first service cell includes selecting a sender of the first discovery signal as a relay.

[0697] As an embodiment, the first message is the Nth RRC reconstruction request attempt initiated by the first timer of the first transmitter 1002 during operation, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; and the transmission method of the N RRC reconstruction requests to the first service cell is through relay transmission.

[0698] As an embodiment, the first transmitter 1002 selects a first serving cell; sends a first wireless signal, where the first wireless signal includes a first message, where the first message is used to request RRC reconstruction; and starts a second timer along with sending the first message;

[0699] The transmission method from the first node to the first service cell is through a first relay, and a first timer is started in response to selecting the first relay; the first relay is an L2 U2N relay; and expiration of the first timer is used to trigger the first node to enter an RRC idle state.

[0700] As an embodiment, the behavior of selecting the first serving cell includes performing relay selection and finding a suitable L2 U2N relay, namely, the first relay; and the first serving cell is a serving cell of the first relay.

[0701] As a sub-embodiment of this embodiment, when the first relay is in an RRC connected state, the first serving cell is a primary cell of the first relay.

[0702] As an embodiment, transmission through the indirect path means that the data transmission between the first node and the network is forwarded through a relay; and transmission through the direct path means that the data transmission between the first node and the network does not pass through a relay.

[0703] As an embodiment, the first transmitter 1002 selects a first relay; sends a first wireless signal, where the first wireless signal includes a first message, where the first message is used to request RRC reconstruction; and starts a second timer along with sending the first message;

[0704] The first transmitter 1002 restarts the second timer after the second timer expires; and sends a third wireless signal along with the restart of the second timer, where the third wireless signal includes a third message, and the third message is used to request an RRC connection;

[0705] The first relay is an L2 U2N relay.

[0706] As an embodiment, in response to selecting the first relay, the first timer is stopped.

[0707] As an embodiment, the first message belongs to a first RRC reconstruction process, and the initiation of the first RRC reconstruction process triggers the start of the first timer.

[0708] As an embodiment, the phrase "the second timer expires" starts a second timer for the behavior.

[0709] As an embodiment, expiration of the second timer triggers the first node to perform relay selection and the first node finds a suitable relay.

[0710] As a sub-embodiment of this embodiment, the suitable relay is a suitable L2 U2N relay.

[0711] As a sub-embodiment of this embodiment, the suitable relay is a suitable L2 U2N relay UE.

[0712] As a sub-embodiment of this embodiment, the suitable relay is not the first relay.

[0713] As a sub-embodiment of this embodiment, the suitable relay is the first relay.

[0714] As an embodiment, expiration of the first timer is used to trigger the first node to enter the RRC idle state.

[0715] As an embodiment, the actions of starting the second timer and restarting the second timer both belong to the first RRC reconstruction process.

[0716] As an embodiment, the first relay is a suitable L2 U2N relay.

[0717] As an embodiment, the first relay is a suitable L2 U2N relay UE.

[0718] As an embodiment, the first receiver 1001 receives a first configuration message, where the first configuration message is used to configure the second timer.

[0719] As a sub-embodiment of this embodiment, the phrase configuring the second timer includes configuring the number of times the second timer can be restarted during an RRC reconstruction process.

[0720] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reconstruction process is greater than 0.

[0721] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reconstruction process is greater than 1.

[0722] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reconstruction process is equal to 1.

[0723] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reconstruction process is equal to 2.

[0724] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reestablishment process is limited.

[0725] As a sub-embodiment of this embodiment, the number of times that the second timer can be restarted during an RRC reestablishment process is unlimited.

[0726] As a sub-embodiment of this embodiment, expiration of the second timer when it is last restarted during an RRC reconstruction process triggers the first node to enter an RRC idle state.

[0727] As an embodiment, the first configuration message includes a system information block.

[0728] As an embodiment, the first configuration message is an RRC message.

[0729] As an embodiment, the first configuration message is or includes RRCReconfiguration.

[0730] As an embodiment, the L2 U2N relay is a L2 U2N relay UE.

[0731] As an embodiment, the first timer is not T301.

[0732] As an embodiment, the first timer is not T311.

[0733] As an embodiment, the first timer is T311.

[0734] As an embodiment, the first node is a user equipment (UE).

[0735] As an embodiment, the first node is a terminal supporting a large delay difference.

[0736] As an embodiment, the first node is a terminal supporting NTN.

[0737] As an embodiment, the first node is an aircraft.

[0738] As an embodiment, the first node is a vehicle-mounted terminal.

[0739] As an embodiment, the first node is a relay.

[0740] As an embodiment, the first node is a vessel.

[0741] As an embodiment, the first node is an Internet of Things terminal.

[0742] As an embodiment, the first node is an industrial Internet of Things terminal.

[0743] As an embodiment, the first node is a device supporting low-latency and high-reliability transmission.

[0744] As an embodiment, the first receiver 1001 includes at least one of the antenna 452, receiver 454, receiving processor 456, multi-antenna receiving processor 458, controller / processor 459, memory 460, or data source 467 in Example 4.

[0745] As an embodiment, the first transmitter 1002 includes at least one of the antenna 452, transmitter 454, transmit processor 468, multi-antenna transmit processor 457, controller / processor 459, memory 460, or data source 467 in Embodiment 4.

[0746] A person of ordinary skill in the art can understand that all or part of the steps in the above method can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a hard disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module unit in the above embodiment can be implemented in the form of hardware or in the form of a software function module, and the present application is not limited to any specific form of software and hardware combination. The user equipment, terminal and UE in the present application include but are not limited to drones, communication modules on drones, remote-controlled aircraft, aircraft, small aircraft, mobile phones, tablet computers, notebooks, vehicle-mounted communication equipment, wireless sensors, Internet cards, Internet of Things terminals, RFID terminals, NB-IoT terminals, MTC (Machine Type Communication, machine type communication) terminals, eMTC (enhanced MTC, enhanced MTC) terminals, data cards, Internet cards, vehicle-mounted communication equipment, low-cost mobile phones, low-cost tablet computers, satellite communication equipment, ship communication equipment, NTN user equipment and other wireless communication equipment. The base stations or system equipment in this application include but are not limited to macrocell base stations, microcell base stations, home base stations, relay base stations, gNB (NR Node B) NR Node B, TRP (Transmitter Receiver Point), NTN base stations, satellite equipment, flight platform equipment and other wireless communication equipment.

[0747] The above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A first node for wireless communication, wherein: include: A first transmitter starts a first timer; Selecting a first serving cell; Sending a first wireless signal, the first wireless signal including a first message, the first message being used to request RRC reestablishment; starting a second timer along with sending the first message; operating the first timer according to a transmission mode at least to the first serving cell; Sending a third wireless signal, where the third wireless signal includes a third message, where the third message is used to request an RRC connection; Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the operation of the first timer according to the transmission method to at least the first service cell includes: when the transmission method to the first service cell is through relay transmission, as a response to selecting the first service cell, stopping the first timer; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after selecting the first service cell.

2. The first node according to claim 1, characterized in that: include: The first receiver receives a second wireless signal, wherein the second wireless signal includes a second message, and the second message is used to determine that the first message is not successfully distributed.

3. The first node according to claim 2, characterized in that: The second message is used to trigger the first transmitter to stop the first timer and the second timer, and the first node enters the RRC idle state; The third wireless signal is sent when the first node enters the RRC idle state; and the third message is used to request to establish an RRC connection.

4. The first node according to claim 2, characterized in that: include: The second message is used to trigger the first transmitter to restart the second timer and send the third message; The third message is used to request RRC re-establishment.

5. The first node according to any one of claims 1 to 4, characterized in that: include: A first receiver receives a fourth wireless signal, where the fourth wireless signal includes a fourth message, and the fourth message is used to feed back the third message; In response to receiving the fourth message, the first transmitter stops the first timer and the second timer.

6. The first node according to any one of claims 2 to 4, characterized in that: The second message is used to trigger the reselection of the relay.

7. The first node according to any one of claims 1 to 6, characterized in that: include: A first receiver detects a failure of a first wireless link through which the first wireless signal is sent; In response to detecting the failure of the first radio link, the first receiver stops the second timer and performs serving cell selection.

8. The first node according to any one of claims 1 to 7, characterized in that: include: A first receiver receives a first discovery signal, where the first discovery signal is used to indicate a first serving cell; and selecting the first serving cell includes selecting a sender of the first discovery signal as a relay.

9. The first node according to any one of claims 1 to 8, characterized in that: The first message is the Nth RRC reconstruction request attempt initiated by the first timer of the first transmitter during operation, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; the transmission method of the N RRC reconstruction requests to the first service cell is through relay transmission.

10. A method in a first node for wireless communication, wherein: include: Start the first timer; Selecting a first serving cell; Sending a first wireless signal, the first wireless signal including a first message, the first message being used to request RRC reestablishment; starting a second timer along with sending the first message; operating the first timer according to a transmission mode at least to the first serving cell; Sending a third wireless signal, where the third wireless signal includes a third message, where the third message is used to request an RRC connection; Among them, the expiration of the first timer is used to trigger the first node to enter the RRC idle state; the operation of the first timer according to the transmission method to at least the first service cell includes: when the transmission method to the first service cell is through relay transmission, as a response to selecting the first service cell, stopping the first timer; when the transmission method to the first service cell is direct transmission, continuing to run the first timer after selecting the first service cell.

11. The method in the first node according to claim 10, characterized in that: include: A second wireless signal is received, the second wireless signal including a second message, the second message being used to determine that the first message was not successfully delivered.

12. The method in the first node according to claim 11, characterized in that: The second message is used to trigger stopping the first timer and the second timer, and the first node enters the RRC idle state; The third wireless signal is sent when the first node enters the RRC idle state; and the third message is used to request to establish an RRC connection.

13. The method in the first node according to any one of claims 11, characterized in that: The second message is used to trigger the restart of the second timer and the sending of the third message; the third message is used to request RRC reconstruction.

14. The method in the first node according to any one of claims 10 to 13, characterized in that: receiving a fourth wireless signal, where the fourth wireless signal includes a fourth message, and the fourth message is used to feed back the third message; The fourth message is used to trigger and stop the first timer and the second timer.

15. The method in the first node according to any one of claims 11 to 13, characterized in that: The second message is used to trigger the reselection of the relay.

16. The method in the first node according to any one of claims 10 to 15, characterized in that: detecting that a first wireless link fails, the first wireless signal being sent via the first wireless link; In response to detecting the failure of the first radio link, the second timer is stopped and selection of a serving cell is performed.

17. The method in the first node according to any one of claims 10 to 16, characterized in that: A first discovery signal is received, where the first discovery signal is used to indicate a first serving cell; and selecting the first serving cell includes selecting a sender of the first discovery signal as a relay.

18. The method in the first node according to any one of claims 10 to 17, characterized in that: The first message is the Nth RRC reconstruction request attempt initiated by the first timer during operation, where N is greater than 1, and the service cells targeted by the N RRC reconstruction request attempts are all the first service cell; the transmission method of the N RRC reconstruction requests to the first service cell is through relay transmission.

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