Method performed by a user equipment and user equipment

Abstract

The application provides a method executed by a user equipment and the user equipment. The method executed by the user equipment is a method of a RRC connection reestablishment procedure executed by a user equipment (UE), comprising the following steps: the UE triggers or initiates the RRC connection reestablishment procedure; in the process of initiating the RRC connection reestablishment, the UE initiates a timer T311 and performs cell selection or relay selection; in the case that the UE selects a suitable cell or the UE selects a suitable relay, the UE stops the T311, wherein the suitable cell is a cell whose measurement value or level value meets the cell selection rule, and the suitable relay is a relay whose measurement value or level value meets the relay selection rule.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically, to a method performed by a user equipment and a corresponding user equipment. Background Technology

[0002] In order to provide services, in one scenario, a remote UE can communicate with a base station through a relay UE.

[0003] After a remote UE establishes an RRC connection with the base station through a relay UE, the remote UE is in an RRC connected state. The remote UE can trigger an RRC connection re-establishment process under the following conditions.

[0004] Case 1: The connection between the remote UE and the relay UE failed, for example, the remote UE detected that the number of HARQ retransmissions exceeded the preset threshold.

[0005] Scenario 2: The remote UE receives a handover command from the base station, which could be to switch the remote UE from its currently connected relay UE to another relay UE (target relay UE) or to a new cell (target cell). However, the remote UE fails to establish a connection with the target relay UE or the target cell, resulting in a handover failure.

[0006] In existing technologies, a UE only performs cell selection during RRC connection re-establishment. When a suitable cell is selected, it initiates access within that cell. However, for remote UEs, the re-establishment process should consider the presence of other candidate relay UEs in the vicinity. Therefore, how a remote UE should perform the RRC connection re-establishment process is a problem that needs to be solved. Summary of the Invention

[0007] This invention proposes a solution to the problem of how a remote UE performs the RRC connection re-establishment process.

[0008] According to one aspect of the present invention, a method is provided for an RRC connection re-establishment process performed by a user equipment (UE), comprising the following steps:

[0009] The UE triggers or initiates the RRC connection re-establishment process;

[0010] During the RRC connection re-establishment process, the UE starts timer T311 and performs cell selection or relay selection.

[0011] When the UE selects a suitable cell or a suitable relay, the UE stops T311. The suitable cell is a cell whose measured value or voltage level meets the cell selection rules, and the suitable relay is a relay whose measured value or voltage level meets the relay selection rules.

[0012] Of the methods described above that are performed by the user equipment, the preferred method is...

[0013] Non-remote UEs only perform cell selection;

[0014] Remote UEs outside the coverage area only perform relay selection;

[0015] Remote UEs within the coverage area can perform cell selection and relay selection.

[0016] Of the methods described above that are performed by the user equipment, the preferred method is...

[0017] The UEs capable of performing cell selection and relay selection execute the following sequence:

[0018] First, perform cell selection. If no suitable cell is found, then perform relay selection.

[0019] First, perform relay selection; if no suitable relay is found, then perform cell selection; or

[0020] The UE performs cell selection and relay selection according to the instructions from the network side.

[0021] Of the methods described above that are performed by the user equipment, the preferred method is...

[0022] The network-side indication received by the UE is carried in the reconfiguration message, which also carries information about handover or synchronization to the target relay or target cell.

[0023] Of the methods described above that are performed by the user equipment, the preferred method is...

[0024] This instruction directly tells the UE to perform cell selection only, or relay selection only, or to perform cell selection first and then relay selection, or to perform relay selection first and then cell selection; or...

[0025] This instruction information is used to assist the UE in determining the order or sequence of cell selection and relay selection.

[0026] Of the methods described above that are performed by the user equipment, the preferred method is...

[0027] The UE determines the priority of performing relay selection and cell selection based on the received reconfiguration message carrying information about handover or synchronization to the target relay or target cell.

[0028] Of the methods described above that are performed by the user equipment, the preferred method is...

[0029] The UE stops T311 if it has selected a suitable relay and established a PC5 connection with it. This includes the following two cases:

[0030] The UE first selects a suitable trunk, but a PC5 connection has not yet been established between the UE and the selected suitable trunk. Then, the UE stops T311 after establishing a PC5 connection with the trunk.

[0031] If the UE determines one of the relays with which it has already established a PC5 connection as a suitable relay, then the UE stops T311.

[0032] Of the methods described above that are performed by the user equipment, the preferred method is...

[0033] When T311 times out, set parameters related to cell selection and / or relay selection according to the UE type.

[0034] Among them, the type of UE mentioned above refers to the way the UE is connected to the base station, whether it is a remote UE or a non-remote UE, or whether the UE is within or outside the coverage area.

[0035] Of the methods described above that are performed by the user equipment, the preferred method is...

[0036] When the UE selects a suitable cell, the UE starts timer T301;

[0037] When the UE selects a suitable relay, timer T301-X is started;

[0038] When T301 or T301-X times out, the UE enters the idle state.

[0039] According to another aspect of the present invention, a user equipment is provided, comprising:

[0040] Processor; and

[0041] Memory, which stores instructions

[0042] When the above instructions are executed by the above processor, the above user equipment performs the method described above.

[0043] According to the method performed by the user equipment involved in this disclosure and the corresponding user equipment, the UE can appropriately perform the RRC connection re-establishment process. Attached Figure Description

[0044] Figure 1 This is a schematic diagram illustrating a communication scenario between a remote UE, a relay UE, and a base station.

[0045] Figure 2 This is a schematic diagram illustrating another communication scenario between a remote UE, a relay UE, and a base station.

[0046] Figure 3 This is a flowchart illustrating a method performed by a user equipment according to an embodiment of the present invention.

[0047] Figure 4 This is a simplified structural block diagram of the user equipment involved in the present invention. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. Furthermore, for the sake of simplicity, detailed descriptions of well-known technologies not directly related to the present invention have been omitted to prevent confusion in understanding the present invention.

[0049] Before proceeding with the detailed description, the following explanation is provided for several terms mentioned in this invention. Unless otherwise specified, the terms used in this invention shall have the meanings described below.

[0050] UE User Equipment

[0051] NR New Radio - Next-Generation Wireless Technology

[0052] LTE Long Term Evolution technology

[0053] eLTE Enhanced Long Term Evolution

[0054] Radio Resource Control (RC)

[0055] MAC Medium Access Control (layer)

[0056] MAC CE MAC Control Element

[0057] SDAP Service Data Adaptation Protocol

[0058] The following description uses NR mobile communication systems and their subsequent evolutions as example application environments, taking NR-supporting base stations and UE devices as examples, to specifically describe several embodiments according to the present invention. However, it should be noted that the present invention is not limited to the following embodiments, but is applicable to many other wireless communication systems, such as eLTE, NB-IoT, or LTE-M systems. Furthermore, it is applicable to other base stations and UE devices, such as base stations and UE devices supporting eLTE / NB-IoT / LTE-M.

[0059] Near Field Communication

[0060] Remote UEs and relay UEs connect wirelessly via near-field communication (NFC) to transmit data or signaling. The NFC method mentioned in this article primarily refers to sidelink connections. However, it can also be Wi-Fi or other connection methods. The reference point between UEs based on the sidelink connection is called PC5; therefore, the connection between a remote UE and a relay UE can be referred to as a PC5 connection.

[0061] Uu RRC connection and status

[0062] The reference point between the UE and the radio access network is called Uu, therefore the connection between the UE and the radio access network is called a Uu connection. In a Uu connection, depending on the state of the Uu RRC connection, the UE's state can be divided into idle state (RRC_IDLEstate), inactive state (RRC_INACTIVE state), and connected state (RRC_CONNECTED state). After an RRC connection is established, the UE can be in the INACTIVE or CONNECTED state. If no RRC connection is established, the UE is in the IDLE state.

[0063] Once an RRC connection is established between the remote UE and the radio access network, the remote UE can be in the INACTIVE or CONNECTED state; if no RRC connection is established, the UE is in the IDLE state. Similarly, a relay UE can also be in one of these three states.

[0064] It should be noted that when the remote UE is in the RRC connected state, the relay UE must be in the RRC connected state; when the remote UE is in the RRC INACTIVE / IDLE state, the relay UE can be in any of the three states: RRC connected state, INACTIVE / IDLE state, etc.

[0065] Furthermore, the PC5 connection between the remote UE and the relay UE does not affect the Uu connection of either the remote UE or the relay UE; the two connections are independent.

[0066] RRC connection re-establishment process

[0067] In existing technology, when the RRC connection re-establishment process is triggered, the UE starts timer T311 and performs cell selection. If no suitable cell is found, when T311 times out, the UE will perform corresponding operations and enter the idle state. The reason for releasing the RRC connection can be set to RRC connection failure.

[0068] This article describes a typical scenario such as Figure 1 As shown, the left side represents the remote UE, the middle side represents the relay UE, and the right side represents the base station, indicating communication between the radio access network and the relay UE. The remote UE and the relay UE are connected via PC5. The ellipse represents the coverage area of ​​the base station. Since the remote UE is not within the coverage area of ​​the base station, it cannot communicate directly with the base station, thus requiring the relay UE to provide relay services. Such a remote UE is considered an out-of-coverage remote UE.

[0069] Another typical scenario described in this article is... Figure 2 As shown, the left side represents the remote UE, the middle side represents the relay UE, and the right side represents the base station, indicating communication between the radio access network and the relay UE. The remote UE and the relay UE are connected via PC5. The ellipse represents the coverage area of ​​the base station. The remote UE is located at the edge of the base station's coverage area. Due to the weak signal of the base station, it cannot communicate directly with the base station and therefore needs the relay UE to provide relay services. Such a remote UE is considered an in-coverage remote UE.

[0070] Example 1

[0071] like Figure 3As shown in the figure, this embodiment provides a method executed by a user equipment, which is a method for the RRC connection re-establishment process executed by the user equipment.

[0072] Step 1: The UE triggers or initiates the RRC connection re-establishment process (refer to step S301).

[0073] The UE may trigger or initiate the RRC connection re-establishment process under the following circumstances, but this is not a limitation:

[0074] Radio link failure detected;

[0075] The reconfiguration attempt for synchronization failed.

[0076] Integrity check failed.

[0077] Step 2: During the RRC connection re-establishment process, the UE starts timer T311 and performs cell selection or relay selection (refer to step S302). Here, we take the existing T311 as an example; it could also be a newly defined timer used for RRC connection re-establishment.

[0078] Preferably, non-remote UEs only perform cell selection;

[0079] Preferably, the remote UE can perform cell selection and relay selection.

[0080] Preferably, remote UEs out of coverage only perform relay selection; remote UEs in coverage can perform both cell selection and relay selection.

[0081] For the UEs mentioned above that can perform cell selection and relay selection, the execution order can be as follows:

[0082] First, the UE performs cell selection. If no suitable cell is found, relay selection is performed. Preferably, the UE first performs cell selection and starts Timer 1. If no suitable cell is found when Timer 1 times out, the UE performs relay selection. If a suitable cell is selected during the execution of Timer 1, the UE stops Timer 1. In other words, the UE performs cell selection for a period of time, and then performs relay selection if no suitable cell is found. When the duration of Timer 1 is set to infinity, it can be assumed that the UE only performs cell selection; when the duration of Timer 1 is set to 0, it can be assumed that the UE only performs relay selection.

[0083] First, relay selection is performed. If no suitable relay is found, cell selection is performed. Preferably, the UE first performs relay selection and starts Timer 2. If Timer 2 times out and no suitable relay is found, the UE performs cell selection. If a suitable relay is selected during the execution of Timer 2, the UE stops Timer 2. In other words, the UE performs relay selection for a period of time, and performs cell selection only if no suitable relay is found. When the duration of Timer 2 is set to infinity, it can be assumed that the UE only performs relay selection; when the duration of Timer 2 is set to 0, it can be assumed that the UE only performs cell selection.

[0084] Timer 1 and Timer 2 can be the same timer.

[0085] In addition, the UE can also perform cell selection and relay selection based on instructions from the network side. The UE can receive instructions from the network side, which can be carried in a reconfiguration message. Preferably, such a reconfiguration message also carries information about handover or synchronization to the target relay or target cell.

[0086] One possible way to display the indication is that the indication information can directly instruct the UE to perform only cell selection, only relay selection, or to perform cell selection first and then relay selection; or to perform relay selection first and then cell selection. This indication information can also be information used to assist the UE in determining the order or sequence of cell selection and relay selection, such as priority information for cell selection or relay selection. For example, if the priority of relay selection is set higher than that of cell selection, then based on this indication information, the UE will always prioritize relay selection, and vice versa.

[0087] One implicit indication method is for the UE to determine the priority of relay selection and cell selection based on the received reconfiguration message carrying information about handover or synchronization to a target relay or target cell. For example, if the reconfiguration message received by the UE carries information about synchronization to (or handover to) a target relay, then a re-establishment process is initiated if the reconfiguration used for synchronization fails. In this process, the UE prioritizes relay selection. As another example, if the reconfiguration message received by the UE carries information about synchronization to a target cell, then a re-establishment process is initiated if the reconfiguration used for synchronization fails, in which case the UE prioritizes cell selection.

[0088] Step 3: The UE stops T311 under one of the following conditions (refer to step S303):

[0089] - The UE selected a suitable cell.

[0090] - The UE selects a suitable relay.

[0091] A suitable cell is one whose measured or voltage levels meet the cell selection criteria.

[0092] A suitable cell can be defined as a cell in which the UE's received signal level meets a certain criterion, such as the existing S criterion. Such a received signal level can be calculated based on the measured value of the cell's received signal level, such as RSRP or RSRQ, or calculated in other ways; there are no restrictions on this.

[0093] A suitable relay is one whose measured or voltage level satisfies the rules for relay selection.

[0094] A suitable relay can be

[0095] The UE measures / detects the wireless signal of the PC5 interface, such as the signal strength of the sidelink discovery message. If the measured value, or the level value calculated based on the measured value, meets the relay selection criteria, the relay can be considered a suitable relay. Alternatively, the UE can measure the RSRP value of the sidelink unicast connection. If the measured value, or the level value calculated based on the measured value, meets the relay selection criteria, the relay can be considered a suitable relay. The relay selection criteria can be that the measured value or the level value is not lower than a preset threshold, etc.

[0096] Preferably, the UE can also stop T311 if a suitable relay has been selected and a PC5 connection has been established with it. This includes two cases:

[0097] Scenario 1: The UE first selects a suitable relay, but a PC5 connection has not yet been established between the UE and the selected suitable relay. Then, the UE stops T311 after establishing a PC5 connection with the relay.

[0098] Scenario 2: Alternatively, the UE can determine that one of the relays with which it has already established a PC5 connection is a suitable relay, in which case the UE can stop T311.

[0099] As a supplement to this scheme, if the UE cannot select a suitable relay or cell, the UE will enter an idle state when the T311 timeout occurs.

[0100] Example 2

[0101] Based on Example 1, when T311 times out, parameters related to cell selection and / or relay selection are set according to the UE type. Here, the UE type preferably refers to the connection method between the UE and the base station. For example:

[0102] When the UE connects to the base station directly via the Uu interface, if the T311 timeout occurs, the UE sets the parameter nosuitableCellFound to true, and this parameter will be recorded in the report provided by the UE to the base station.

[0103] When the connection between the UE and the base station is established through a relay UE (i.e., not a direct connection), the UE can choose not to set the parameter `nosuitableCellFound` to true in the event of a T311 timeout. Alternatively, the UE can also set the parameter `nosuitablerelayFound` to true in the event of a T311 timeout. Preferably, depending on the actual situation, if the UE performs cell selection during the re-establishment process, then the UE sets the parameter `nosuitableCellFound` to true in the event of a T311 timeout; if the UE also performs relay selection during the re-establishment process, then the UE can also set the parameter `nosuitablerelayFound` to true in the event of a T311 timeout.

[0104] Here, nosuitableCellFound refers to the parameter used to record when there is no suitable cell, and nosuitablerelayFound refers to the parameter used to record when there is no suitable relay. When they are true, it means that there is no suitable cell / relay, and when they are false, it means that there is a suitable cell / relay.

[0105] Here, UE type can also refer to remote UE or non-remote UE. A remote UE is one that establishes an RRC connection with the base station via a relay, while a non-remote UE is one that does not establish an RRC connection with the base station via a relay, or one that communicates directly with the base station via the Uu interface. For example:

[0106] For remote UEs, in the event of a T311 timeout, the UE may not set the parameter nosuitableCellFound to true; alternatively, in the event of a T311 timeout, the UE may also set the parameter nosuitablerelayFound to true. Preferably, depending on the actual situation, if the UE performs cell selection during the re-establishment process, then in the event of a T311 timeout, the UE sets the parameter nosuitableCellFound to true; if the UE also performs relay selection during the re-establishment process, then in the event of a T311 timeout, the UE may also set the parameter nosuitablerelayFound to true.

[0107] For non-remote UEs, in the event of a T311 timeout, the UE setting parameter nosuitableCellFound will be true.

[0108] In addition, the UE type can also refer to whether the UE is in coverage or out of coverage. For example...

[0109] For UEs in coverage, if the T311 operation times out, the UE sets the parameter nosuitableCellFound to true. Optionally, if the UE also selects a relay, the UE sets the parameter nosuitablerelayFound to true.

[0110] For UEs that are out of coverage, the E setting parameter nosuitablerelayFound will be true if the T311 operation times out.

[0111] Example 3

[0112] Based on Example 1, when the UE selects a suitable cell, the UE starts timer T301; when the UE selects a suitable relay, timer T301-X is started. This example can also be used independently for the RRC re-establishment process when the UE selects a suitable relay. Here, we take the existing T301 as an example; it could also be a newly defined timer for RRC connection re-establishment.

[0113] The values ​​of T301 and T301-X can be broadcast in system information or sent to the UE via dedicated signaling.

[0114] When T301 or T301-X times out, the UE enters the idle state.

[0115] Another way to implement this solution is as follows:

[0116] When the UE selects a suitable cell, the UE sets the value of T301 to the value broadcast in the system information or the value contained in the information cell spcellconfig, and then starts timer T301;

[0117] When the UE selects a suitable relay, the UE sets the value of T301 to the value broadcast in the system information for remote UE, or the value for T301 included in the handover command received by the UE. This handover command instructs the UE to hand over from the current relay or serving cell to a target relay, and then starts timer T301.

[0118] As a supplement to this solution, when the UE receives the RRC connection re-establishment message, it can stop the running timer T301 or T301-X.

[0119] Figure 4 This is a simplified structural block diagram of the user equipment involved in the present invention. Figure 4 As shown, the user equipment UE400 includes a processor 401 and a memory 402. The processor 401 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 402 may include, for example, volatile memory (such as random access memory, RAM), a hard disk drive (HDD), non-volatile memory (such as flash memory), or other memory. Program instructions are stored on the memory 402. When executed by the processor 401, these instructions can perform the methods described in detail herein, executed by the user equipment.

[0120] A program running on a device according to the invention can be a program that enables a computer to perform the functions of embodiments of the invention by controlling a central processing unit (CPU). The program, or the information processed by the program, can be temporarily stored in volatile memory (such as random access memory, RAM), hard disk drive (HDD), non-volatile memory (such as flash memory), or other memory systems.

[0121] Programs used to implement the functions of the various embodiments of the present invention can be recorded on a computer-readable recording medium. The corresponding functions can be implemented by causing a computer system to read and execute the programs recorded on the recording medium. The term "computer system" here can refer to a computer system embedded in the device, and may include an operating system or hardware (such as peripheral devices). "Computer-readable recording medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-time dynamic storage program recording medium, or any other computer-readable recording medium.

[0122] Various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., monolithic or multi-chip integrated circuits). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. A general-purpose processor may be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above circuits may be digital circuits or analog circuits. In cases where advancements in semiconductor technology have led to new integrated circuit technologies that replace existing integrated circuits, one or more embodiments of the present invention may also be implemented using these new integrated circuit technologies.

[0123] Furthermore, the present invention is not limited to the embodiments described above. Although various examples of the embodiments have been described, the present invention is not limited thereto. Fixed or non-mobile electronic devices installed indoors or outdoors can be used as terminal devices or communication devices, such as AV equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0124] As described above, embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific structure is not limited to the above embodiments, and the present invention also includes any design modifications that do not depart from the spirit of the invention. Furthermore, various modifications can be made to the present invention within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of the present invention. In addition, components with the same effects described in the above embodiments can be substituted for each other.

Claims

1. A method executed by a user equipment, the method comprising: When initiating the Radio Resource Control (RRC) connection re-establishment process, the first timer is started and a selection is performed; Upon performing the selection, the first timer is stopped and the second timer is started, regardless of whether the selection is a suitable cell selection or a suitable relay selection. If the appropriate cell selection is performed, the second timer is started using the first value, and If the appropriate relay selection is performed, the second value is used to start the second timer; and The second timer is stopped upon receiving an RRC re-establishment message.

2. A user equipment, comprising: processor; as well as Memory, stored instructions Wherein, the instruction, when executed by the processor, causes the user equipment to: When initiating the Radio Resource Control (RRC) connection re-establishment process, the first timer is started and a selection is performed; Upon performing the selection, the first timer is stopped and the second timer is started, regardless of whether the selection is a suitable cell selection or a suitable relay selection. If the appropriate cell selection is performed, the second timer is started using the first value, and If the appropriate relay selection is performed, the second value is used to start the second timer; and The second timer is stopped upon receiving an RRC re-establishment message.

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