Method executed by user equipment and user equipment

Abstract

The invention provides a method executed by user equipment and the user equipment. The method executed by user equipment UE comprises the following steps: the UE starts a random access process; the UE judges whether the random access process is triggered by a physical downlink control channel command (PDCCH) order oriented to a TRP or TAG associated with a special cell (SpCell) under the condition that the number of times of transmission of a preamble sequence exceeds a threshold value of the number of times of transmission in the execution process of the random access process; under the condition that the UE judges that the random access process is triggered by the PDCCH order oriented to the TRP or TAG associated with the SpCell, the UE executes at least one of the following operations: stopping a TA timer associated with a first TAG in at least two TAGs associated with the SpCell; and determining that the random access procedure is not successfully completed.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and more particularly, to a method executed by a user equipment and corresponding user equipment. Background Art

[0002] In order to further enhance the uplink transmission and reception performance in NR technology, the Third Generation Partnership Project (3GPP) intends to study uplink transmission under multiple transmit and receive nodes (TRPs). In a service cell, more than one transmit and receive node TRP can be deployed, and each TRP provides services to the same UE, such as Figure 1 As shown. Due to the different physical distances between different TRPs and UEs, the propagation delays are different, so that the values ​​of the timing advance (TimingAdvance) used by the UE when sending for different TRPs are different. In the prior art, the UE receives a PDCCH order (PDCCHorder) from the network layer to trigger a random access process, and obtains a valid TA value in the process, thereby updating the timing advance it maintains. In the prior art, during the random access process performed by the UE, when the number of transmissions of the leading sequence exceeds the maximum allowed number, the UE can indicate a random access problem to the upper layer, which leads to RRC connection reconstruction, thereby causing service delays. Under the configuration of multiple TRP nodes, if this operation is continued, the result is that if there is a problem with the random access on one TRP, the entire link will be rebuilt, but in fact another TRP can still work normally. In this case, rebuilding the link is not conducive to the maintenance of network performance. Therefore, how to avoid premature link reconstruction is a problem that needs to be solved. Summary of the invention

[0003] In order to solve the above problem, the present invention provides a method performed by a user equipment and the user equipment.

[0004] According to one aspect of the present invention, a method performed by a user equipment UE is provided, comprising: the UE starts a random access process; during the execution of the random access process, when the number of transmissions of a preamble sequence exceeds a transmission number threshold, the UE determines whether the random access process is triggered by a physical downlink control channel command PDCCH order for a TRP or TAG associated with a special cell SpCell; when the UE determines that the random access process is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, the UE performs at least one of the following operations: stops a TA timer associated with a first TAG among at least two TAGs associated with the SpCell; and determines that the random access process is not successfully completed.

[0005] In the method of the first aspect above, preferably, if the value of the variable PREAMBLE TRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, it means that the number of times the preamble sequence is sent exceeds the sending number threshold.

[0006] In the method of the first aspect above, preferably, the first TAG is a TAG for which the random access procedure triggered by the PDCCH order is directed.

[0007] In the method of the first aspect above, preferably, when the UE determines that the random access procedure currently started is not triggered by the PDCCH order, the UE indicates a random access problem to an upper layer of a media access control MAC layer.

[0008] In the method of the above-mentioned first aspect, preferably, the at least two TAGs also include a second TAG associated with the SpCell. When the UE determines that the random access process is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, the UE further determines whether the TA timer associated with the second TAG is running. When the TA timer associated with the second TAG is running, the UE performs at least one of the following operations: stops the TA timer associated with the first TAG; determines that the random access process is not successfully completed.

[0009] In the method of the first aspect above, preferably, when the TA timer associated with the second TAG is not running, the UE performs the following operations: indicating a random access problem to an upper layer of a MAC layer of the UE.

[0010] In the method of the first aspect above, preferably, when the UE determines that the random access process is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, the UE further determines whether the value of the variable RA_PROBLEM_OCCUR is true. When the value of the variable RA_PROBLEM_OCCUR is true, the UE performs the following operations: indicating the random access problem to the upper layer of the MAC layer of the UE.

[0011] In the method of the first aspect above, preferably, when the value of the variable RA_PROBLEM_OCCUR is false, the UE performs at least one of the following operations: setting the value of the variable RA_PROBLEM_OCCUR to true; stopping the TA timer associated with the first TAG; and determining that the random access procedure is not successfully completed.

[0012] In the method of the first aspect above, preferably, when the TA timer associated with the second TAG is running, the UE performs at least one of the following operations: stops the TA timer associated with the first TAG; determines that the random access procedure is not successfully completed; and sets the value of the variable RA_PROBLEM_OCCUR to true. When the TA timer associated with the second TAG is not running, the UE further determines whether the value of the variable RA_PROBLEM_OCCUR is true. If the value of RA_PROBLEM_OCCUR is true, the UE indicates the random access problem to the upper layer of the MAC layer; if the value of RA_PROBLEM_OCCUR is false, the UE starts a random access procedure.

[0013] In addition, according to a second aspect of the present invention, a user equipment is provided, comprising: a processor; and a memory storing instructions, wherein the instructions execute the method described above when executed by the processor.

[0014] Effects of the Invention

[0015] According to the method performed by the user equipment and the user equipment of the present invention, under the configuration of multiple TRP nodes, it is possible to avoid premature link reconstruction, which can be beneficial to the maintenance of network performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram showing uplink transmission under multiple transmitting receiving nodes (TRPs).

[0017] Figure 2 It is a schematic diagram showing the time advance.

[0018] Figure 3 is a flow chart showing the four-step random access process.

[0019] Figure 4 is a flow chart showing a two-step random access process.

[0020] Figure 5 is a flowchart showing a method executed by a user equipment according to an embodiment of the present invention.

[0021] Figure 6 It is a brief structural block diagram of the user equipment involved in the present invention. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. In addition, for the sake of simplicity, detailed descriptions of known technologies that are not directly related to the present invention are omitted to prevent confusion in understanding the present invention.

[0023] Before the detailed description, some terms mentioned in the present invention are explained as follows. Unless otherwise specified, the terms involved in the present invention have the following meanings.

[0024] UE:User Equipment, user equipment;

[0025] NR: New Radio, a new generation of wireless technology;

[0026] LTE: Long Term Evolution, long-term evolution technology;

[0027] eLTE: Enhanced Long Term Evolution, enhanced long-term evolution technology;

[0028] RRC: Radio Resource Control, radio resource control (layer);

[0029] MAC: Medium Access Control, media access control (layer);

[0030] MAC CE: MAC Control Element, MAC control element;

[0031] PHY: physical layer, physical layer;

[0032] RB: radio bearer, wireless bearer;

[0033] DRB: Data Radio Bearer, data radio bearer;

[0034] SRB: Signalling Radio Bearer, signaling radio bearer;

[0035] TCI: Transmission Configuration Indicator, transmission configuration indication;

[0036] DCI: Downlink Control Information

[0037] RSRP: Reference Signal Received Power, reference signal received power;

[0038] PRACH: Physical Random Access Channel, physical random access channel;

[0039] PDCCH: Physical Downlink Control Channel, physical downlink control channel;

[0040] RA: Random Access, random access;

[0041] RAR: Random Access Response, random access response;

[0042] TRP: Transmit / Receive Point, sending and receiving node;

[0043] SS:Synchronization Signal,synchronization signal;

[0044] PBCH: Physical Broadcast Channel, physical broadcast channel;

[0045] SSB: SS / PBCH block, synchronized broadcast block;

[0046] CSI-RS: Channel State Information-Reference Signal channel state information reference signal.

[0047] MCG Master Cell Group

[0048] SCG Secondary Cell Group

[0049] SpCell Special Cell

[0050] PCell Primary Cell

[0051] PSCell Primary SCG Cell SCG main service cell

[0052] SCell Secondary Cell auxiliary service cell

[0053] Hereinafter, a description is given of related art of the present invention.

[0054] Time advance N TA

[0055] Time advance N TA It can be used to calculate the timing advance between downlink and uplink.

[0056] like Figure 2 As shown, in order to maintain uplink synchronization, the UE needs to start the transmission of the i-th uplink frame (Uplink Frame i) some time before the start position of the i-th downlink frame (Downlink Frame i). This time period can be determined by the time advance value T TA Characterization, T TA =(N TA +N TA，offset )*T c , where T c It is a time parameter related to the carrier frequency.

[0057] The Timing advance command contains an index value, which is recorded as TA and is used to calculate N TA Upon receiving the Timing advance command included in the random access response, the UE may A To calculate N TA Or T A Indirectly indicates N TA The value of .

[0058] Timing Advance Group

[0059] In the prior art, in order to maintain uplink time alignment (UL time alignment), each serving cell is divided into a TAG, and serving cells with the same time advance belong to the same TAG. In order to manage the validity of the TA value, each TAG can have its own timer timeAlignmentTimer, which is used to control the effective time of the uplink synchronization of the serving cells (ServingCells) belonging to the TAG. When the TA value is updated, the timeAlignmentTimer of the corresponding TAG will be started or restarted; when the timeAlignmentTimer of a TAG times out, it means that the uplink of the serving cell belonging to the TAG is no longer synchronized.

[0060] In the scenario of multiple TRPs, a service cell can contain more than one TRP, and each TRP has its own corresponding time advance. Then one implementation method can be that a service cell can belong to more than one TAG, for example, there can be two TAGs, each TAG corresponds to a TRP, or each TRP has its own associated TAG. Similarly, each TAG can have its own timeAlignmentTimer.

[0061] Another implementation is that a serving cell belongs to a TAG, but the TAG has more than one TA value, for example, a TAG can have at least two TA values, each TA value corresponds to or is associated with a TRP. Similarly, each TA can have its own timeAlignmentTimer, so the TAG can have multiple timeAlignmentTimers.

[0062] In this article, any of the above methods can be used to manage TA.

[0063] In this document, since TRP and TAG / TA correspond to each other, the two terms can be used interchangeably. For example, if the TRP corresponding to the PDCCH order triggering random access is determined, the TAG corresponding to the PDCCH order triggering random access is also determined accordingly.

[0064] PDCCH order

[0065] A proprietary DCI format is used to characterize the PDCCH order. Such DCI is carried in the PDCCH to trigger the random access process. In such a DCI format, the random access preamble index and the SS / PBCH index can be clearly indicated.

[0066] Serving Cell

[0067] The serving cell includes PCell, PSCell and SCell. When the UE works in dual connectivity mode, SpCell can refer to the PCell of MCG or the PSCell of SCG.

[0068] Synchronous Broadcast Block SSB

[0069] When the NR system operates in the high frequency band, the base station often cannot send multiple beams covering the entire cell at the same time. Therefore, beam scanning technology is introduced in the NR system to solve the problem of cell coverage.

[0070] Beam scanning means that the base station only sends one or several beam directions at a certain time, and sends different beams at multiple times to cover all directions required by the entire cell. The synchronized broadcast block set is designed for beam scanning, and is used to send the primary synchronization signal, secondary synchronization signal and physical broadcast channel required by the UE to search for the cell in each beam direction, and these signals constitute a synchronized broadcast block (SSB). The synchronized broadcast block set is a collection of multiple synchronized broadcast blocks within a certain time period. In the same period, each synchronized broadcast block corresponds to a beam direction, and the beam directions of each synchronized broadcast block in a synchronized broadcast block set cover the entire cell.

[0071] In the scenario of multiple TRPs, it can be considered that one TRP corresponds to some SSBs in the synchronous broadcast block set, and another TRP corresponds to some SSBs in the set. The SSBs corresponding to the two constitute the full set of the synchronous broadcast block set, that is, covering the entire cell. Therefore, in the random access process, when the UE selects the random access resource, it needs to first determine the random access beam direction, that is, determine the SSB.

[0072] In the scenario of multiple TRPs, there can also be a primary TRP (primary TRP) corresponding to all SSBs in the synchronized broadcast block set, achieving coverage of the entire cell. At the same time, there are one or more secondary TRPs (Secondary TRPs), and their corresponding beam directions can be partial SSBs, or more subdivided, which can be represented by CSI-RS, that is, corresponding to the beam direction of CSI-RS.

[0073] Therefore, it can be considered that there is a corresponding relationship between TRP and SSB or CSI-RS, or that they are related to each other.

[0074] This correspondence can be directly reflected in the RRC configuration information. For example, if one or more SSB numbers are configured for a TRP, then these SSBs are associated with the TRP; for example, if one or more CSI-RSs are configured for a TRP, then these CSI-RSs are associated with the TRP. Such a correspondence can also be represented indirectly, for example, by TCI states. The UE detects PDCCH on the configured search space. The configuration information of each search space contains information about the control resource set (ControlResource Set, CORESET) used by the search space. The control resource set provides resource blocks in the frequency domain and time domain. Each control resource set is associated with a series of TCI states. Each TCI state contains information about at least one SSB or CSI-RS. The control resource set used for the same search space can be numbered by coresetPoolIndex, where the number value 0 can correspond to the first TRP or primary TRP, the number value 1 can correspond to the second TRP or secondary TRP, and so on. Therefore, the configuration of the TCI state of the resource set can correspond to the TRP corresponding to the resource set, thereby forming a corresponding relationship between the TRP and the SSB or CSI-RS.

[0075] In this document, since TRP and TCI state or coresetPoolIndex correspond to each other, the two terms can be interchanged. For example, if the TRP corresponding to the PDCCH order triggering random access is determined, the TCIstate or coresetPoolIndex corresponding to the PDCCH order triggering random access is also determined accordingly.

[0076] 4-step Random Access procedure (4-step RA)

[0077] The following is a description with reference to the accompanying drawings. Specifically, Figure 3 As shown, the UE performs a 4-step random access process including the following steps:

[0078] Step S300: The UE selects a random access resource for random access.

[0079] - The UE selects a preamble sequence for transmission and sets the sequence number corresponding to the selected preamble to the value of the parameter PREAMBLE_INDEX; and

[0080] -determine the next available PRACH occasion from the PRACH occasions.

[0081] Step S301: The UE sends the selected preamble at the determined PRACH timing.

[0082] Step S302: The UE receives a random access response (Random Access Response, RAR) sent by the base station side.

[0083] If the RAR carries the sequence number (preambleindex id) corresponding to the preamble sent by the UE in step S301, the UE can determine that the RAR is sent to itself.

[0084] Such a RAR will carry a UL grant indicating the PUSCH resources used to transmit message 3.

[0085] The RAR also carries a Timing Advance Command, which contains the index value T used to control the TA value of the timing adjustment. A The value is used to index or correspond to a valid uplink synchronization timing advance TA. When the UE receives such a Timing Advance Command, it will apply the timing advance indicated in it for the next uplink transmission.

[0086] After receiving the above RAR, the UE will apply the Timing Advance Command to obtain a valid TA value. If this random access process is a non-contention based random access process, for example, a dedicated preamble is provided in the PDCCH order, then at this point, the random access process is considered to have been successfully completed. If not, the UE will continue to perform the following steps.

[0087] After receiving the above RAR, the UE processes the UL grant carried in the RAR and indicates it to the lower layer. If this is the first time that the UE successfully receives the above RAR, the UE obtains the MAC PDU for transmission from the multiplexing and assembly entity and stores it in the MSG3 buffer.

[0088] If the UE does not receive the above RAR within the predetermined time, the UE will increase the value of the variable PREAMBLE_TRANSMISSION_COUNTER by 1, and the initial value of the variable is 0. If PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1, the UE considers that the random access process has not been successfully completed. In one case, when the random access preamble sequence is sent on the SpCell, the MAC layer of the UE can indicate the random access problem to the upper layers. The variable PREAMBLE_TRANSMISSION_COUNTER is used to record the number of times the preamble is sent, and the parameter preambleTransMax is a preconfigured value, and its value indicates the maximum number of times the preamble is allowed to be sent.

[0089] Step S303: The UE sends message 3 on the PUSCH resources indicated by the UL grant.

[0090] In this message 3, the UE will carry identification information used for contention conflict resolution.

[0091] Step S304: The UE receives message 4 sent by the base station side.

[0092] If message 4 carries the identification information carried by the UE in message 3, the UE considers that the contention conflict is resolved and the random access process is successfully completed.

[0093] If the UE does not receive the message 4 within the predetermined time, the UE will increase the value of the variable PREAMBLE_TRANSMISSION_COUNTER by 1, and the initial value of the variable is 0. If PREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1, the UE considers that the random access process is not successfully completed and can indicate the random access problem to the upper layer.

[0094] Since the UE undergoes the message transfer process of steps S301 to S304 in the above random access process, it is called a "four-step random access" (4-step RA) process.

[0095] The above four-step random access process can also be called the first type of layer 1 random access (Type-1 layer1 Random Access Procedure, type 1 L1 RA). From the perspective of the physical layer (also known as layer 1), the type 1 L1 RA process at least includes the transmission of the random access preamble sequence (or the transmission of message 1) on the PRACH, and the transmission / reception of the random access response message (Random Access Response Message). The transmission of this random access response message is scheduled by the PDCCH and is transmitted on the PDSCH; in addition, the type 1 L1 RA process can also include the PUSCH scheduled by the uplink grant carried in the random access response, and the subsequent PDSCH for contention resolution.

[0096] 2-step Random Access procedure (2-step RA)

[0097] The following is a description with reference to the accompanying drawings. Specifically, Figure 4 As shown, the two-step random access process includes the following steps:

[0098] Step S400: The UE selects a random access resource for random access.

[0099] -The UE selects a preamble sequence for transmission and sets the sequence number corresponding to the selected preamble to the value of the parameter PREAMBLE_INDEX;

[0100] -determine the next available PRACH occasion from the PRACH occasions; and

[0101] -Determine a PUSCH resource corresponding to the preamble sequence.

[0102] Step S401: The UE sends a message A (MSGA) to the base station.

[0103] Message A includes a preamble and a payload of message A.

[0104] The preamble is sent on the PRACH, and the payload of message A is sent on the PUSCH. The payload of message A is packaged into a MAC PDU and transmitted on the PUSCH. When the UE determines the timing for sending message A, if this is the first time that the UE sends MSG A, the UE obtains the MAC PDU for sending from the multiplexing and assembly entity and saves it in the buffer area of ​​Message A (MSGA buffer).

[0105] Step S402: The UE receives a message B (MSG B) sent by the base station.

[0106] Message B carries information for contention conflict resolution.

[0107] If the UE does not receive the above MSG B within the predetermined time, the UE will increase the value of the variable PREAMBLE_TRANSMISSION_COUNTER by 1. The initial value of the variable is 0. If PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1, the UE considers that the random access process has not been successfully completed and can indicate the random access problem to the upper layer. The variable PREAMBLE_TRANSMISSION_COUNTER is used to record the number of times the preamble is sent, and the parameter preambleTransMax is a preconfigured value, which indicates the maximum number of times the preamble is allowed to be sent.

[0108] In the present invention, network, base station and RAN can be used interchangeably, and the network can be a long-term evolution LTE network, a new radio access technology (New RAT, NR) network, an enhanced long-term evolution eLTE network, or other networks defined in subsequent evolution versions of 3GPP.

[0109] Specific embodiments are listed below to illustrate the processing method of the present invention.

[0110] Example 1

[0111] This embodiment provides a method executed by a user equipment. Figure 5 is a flow chart showing a method performed by a user equipment according to an embodiment of the present invention. Figure 5 As shown, the method performed by the user equipment in Embodiment 1 may include the following steps.

[0112] Step S501: UE initiates / triggers a random access procedure. Such a random access procedure may be the four-step random access as described above, or a two-step random access. Here, the four-step random access is taken as an example.

[0113] The reason for triggering or starting the random access process may be that the UE receives a PDCCH order sent from the network side or the base station side, or that the UE itself has a scheduling request, thereby triggering the random access process; it may also be that the UE triggers a random access request due to a beam failure recovery request, etc.

[0114] Among them, in the random access triggered by the UE's scheduling request, the preamble sequence sent in the process is selected by the UE's MAC layer, so such a random access process is also considered to be a random access process in which the preamble sequence is selected by the UE's MAC layer. In the random access triggered by PDCCHorder or the random access process triggered by the failure of requesting beam recovery, the preamble sequence sent by the UE may be specified by the network side, so such a random access process is also considered to be a random access process in which the preamble sequence is not selected by the UE's MAC layer.

[0115] Step S502: During the execution of the random access procedure, if the number of transmissions of the preamble sequence exceeds the transmission number threshold, as an example, if the value of the variable PREAMBLE_TRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, (PREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1), then the UE can perform corresponding operations according to the following situations:

[0116] In one case, the Random Access Preamble is transmitted on the SpCell, then the UE can further determine whether the random access procedure is triggered / started by a PDCCH order and is directed to a TRP or TAG associated with the SpCell. Alternatively, the UE determines whether the random access procedure is triggered by a PDCCH order indicating TRP or TAG related information.

[0117] For example, the SpCell is associated with at least two TAGs, wherein the TAG targeted by the random access process triggered by the above-mentioned PDCCH order, or the TAG associated with the targeted TRP, or the TAG indicated or associated with the above-mentioned PDCCH order is called the first TAG, and the other TAG can be called the second TAG.

[0118] In one case, the random access procedure for sending the preamble sequence on the SpCell is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, or by the PDCCH order indicating the TRP or TAG related information, then the UE may perform at least one of the following operations:

[0119] - Stop the TA timer associated with the first TAG, or consider that the TA timer associated with the first TAG has timed out. And, correspondingly, corresponding operations when the TA timer times out can be performed;

[0120] - consider the Random Access procedure unsuccessfully completed.

[0121] As a supplement, if the currently started random access process is not triggered by the above PDCCH order, the UE can indicate a random access problem to the upper layer of the MAC layer of the UE (e.g., the RRC layer). After receiving the indicated random access problem, the upper layer of the UE can consider that a radio link failure is detected, and then perform an RRC connection re-establishment operation.

[0122] As a supplement, in another case, for example, the Random Access Preamble is transmitted on an SCell, the UE only determines that the random access process is not successfully completed, and does not need to indicate the random access problem to the upper layer.

[0123] As an illustration, if the UE performs two-step random access, since the two-step random access is always performed on the SpCell, that is, the UE always sends message A on the SpCell (message A includes the preamble and the payload of message A), therefore when the UE performs two-step random access, when applying the scheme of this article, for the judgment of the random access process, the UE does not need to additionally judge whether the random access process is sending the preamble sequence on the SpCell, but only needs to judge whether the random access process is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, or is triggered by the PDCCH order indicating TRP or TAG related information.

[0124] Example 2

[0125] On the basis of Embodiment 1, for the random access process initiated by the UE, if the number of transmissions of the preamble sequence exceeds the transmission number threshold, as an example, if the value of the variable PREAMBLE_TRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, (PREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1), the UE may also perform corresponding operations according to the following situations:

[0126] If the random access process of sending the preamble sequence on the SpCell is triggered by the PDCCH order for the TRP or TAG associated with the SpCell, or is triggered by the PDCCH order indicating TRP or TAG related information, the UE can further determine whether the TAtimer associated with another TAG associated with the SpCell, namely the second TAG, is running.

[0127] In one case, if the TA timer associated with another TAG, namely the second TAG, is running, the UE may perform at least one of the following operations:

[0128] - Stop the TA timer associated with the first TAG, or consider that the TA timer associated with the first TAG has timed out. And, correspondingly, corresponding operations when the TA timer times out can also be performed;

[0129] - consider the Random Access procedure unsuccessfully completed.

[0130] In another case, if the TA timer associated with the second TAG is not running or has timed out, the UE may perform the following operations:

[0131] -Indicate a random access problem to an upper layer of the MAC layer of the UE (eg, the RRC layer).

[0132] Correspondingly, after receiving the random access problem indicated, the upper layer of the UE may consider that a radio link failure (Radio link Failure) is detected, and then perform an RRC connection re-establishment operation.

[0133] Example 3

[0134] On the basis of Embodiment 1 or 2, for the random access process initiated by the UE, if the number of transmissions of the preamble sequence exceeds the transmission number threshold, as an example, if the value of the variable PREAMBLE_TRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, (PREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1), the UE may perform corresponding operations according to the following situations:

[0135] If the random access procedure for sending the preamble sequence on the SpCell is triggered by a PDCCH order for the TRP or TAG associated with the SpCell, or by a PDCCH order indicating TRP or TAG related information, the UE can further determine whether the value of the variable RA_PROBLEM_OCCUR is true:

[0136] In one case, the variable RA_PROBLEM_OCCUR is set to true, then the UE may perform the following operations:

[0137] -Indicates a random access problem to the upper layer of the UE's MAC layer (e.g., the RRC layer)

[0138] In another case, the value of the variable RA_PROBLEM_OCCUR is False, then the UE may perform one or more of the following operations:

[0139] - Set the variable RA_PROBLEM_OCCUR to True;

[0140] - Stop the TA timer associated with the first TAG, or consider that the TA timer associated with the first TAG has timed out. And, correspondingly, corresponding operations when the TA timer times out can be performed;

[0141] -consider the Random Access procedure unsuccessfully completed;

[0142] -Preferably, when the TA timer associated with the second TAG is not running,

[0143] The UE may also initiate a random access procedure.

[0144] The initial value of the variable RA_PROBLEM_OCCUR is false. When the TA timer associated with any TAG (TAGs) associated with the SpCell is started or restarted, the value of the variable RA_PROBLEM_OCCUR is set to false, or to the initial value.

[0145] Here, the value of the variable RA_PROBLEM_OCCUR can also be 0 and 1 (or 1 and 0) to represent the true and false states.

[0146] Example 4

[0147] On the basis of Embodiment 1-3, for the random access process initiated by the UE, if the number of transmissions of the preamble sequence exceeds the transmission number threshold, as an example, if the value of the variable PREAMBLETRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, (PREAMBLE_TRANSMISSION_COUNTER=preambleTransMax+1), the UE can perform corresponding operations according to the following situations:

[0148] If the random access procedure for sending the preamble sequence on the SpCell is triggered by a PDCCH order for the TRP or TAG associated with the SpCell, or by a PDCCH order indicating TRP or TAG related information, the UE can further determine whether another TAG associated with the SpCell, i.e., the second TAG, and its associated TAtimer are running:

[0149] If the TA timer associated with the second TAG is running, the UE may perform at least one of the following operations:

[0150] - Stop the TA timer associated with the first TAG, or consider that the TA timer associated with the first TAG has timed out. And, correspondingly, corresponding operations when the TA timer times out can be performed;

[0151] -consider the Random Access procedure unsuccessfully completed;

[0152] -Set the variable RA_PROBLEM_OCCUR to True

[0153] If the TA_timer associated with the second TAG is not running or has timed out, the UE may further determine whether the value of the variable RA_PROBLEM_OCCUR is true, and then perform corresponding operations based on the determination result:

[0154] - If the value of RA_PROBLEM_OCCUR is true, then a random access problem is indicated to the upper layers of the UE's MAC layer (e.g., the RRC layer).

[0155] - If the value of RA_PROBLEM_OCCUR is false, the UE may initiate a random access procedure;

[0156] - If the value of RA_PROBLEM_OCCUR is false, the UE may also:

[0157] ■Stop the TA timer associated with the first TAG, or consider that the TA timer associated with the first TAG has timed out. And, correspondingly, corresponding operations when the TA timer times out can be performed;

[0158] ■consider the Random Access procedure unsuccessfully completed;

[0159] ■Set the variable RA_PROBLEM_OCCUR to True

[0160] Example 5

[0161] In the foregoing embodiment, when the TA timer runs out of time or is considered to have run out of time, at least one of the following operations may be performed:

[0162] - No uplink transmission other than the random access preamble sequence or message A is performed

[0163] - Clear the HARQ buffer

[0164] -Notify the RRC layer to release PUCCH

[0165] -Notify the RRC layer to release SRS

[0166] - Clear all configured downlink assignments and configured uplink grants

[0167] - Clear PUSCH resources for CSI reporting

[0168] -Maintain / save the NTA value of this TAG.

[0169] Example 6

[0170] In the above embodiment, how the UE determines whether a random access procedure is triggered by a PDCCH order for a TRP or TAG associated with the serving cell, or triggered by a PDCCH order indicating TRP or TAG related information, may be in the following ways:

[0171] Method 1: Determine by CORESETPoolIndex corresponding to the ControlResourceSet configured with the search space for receiving the PDCCH carrying the PDCCH order.

[0172] For example, the UE receives a PDCCH on the search space corresponding to the ControlResourceSet with a CORESETPoolIndex value of 0. Since the corresponding or associated TRP of the ControlResourceSet with a CORESETPoolIndex value of 0 may be TRP-1, for such a PDCCH, when it carries the PDCCH order, the triggered random access procedure is for TRP1; and the UE receives a PDCCH on the search space corresponding to the ControlResourceSet with a CORESETPoolIndex value of 1. Since the corresponding or associated TRP of the ControlResourceSet with a CORESETPoolIndex value of 1 may be TRP-2, for such a PDCCH, when it carries the PDCCH order, the triggered random access procedure is for TRP2.

[0173] The UE may also be configured with a TAG and CORESETPoolIndex or ControlResourceSet association, for example, TAG-1 is associated with a ControlResourceSet with a CORESETPoolIndex value of 1, and TAG-2 is associated with a ControlResourceSet with a CORESETPoolIndex value of 0.

[0174] Then the PDCCH order detected and received by the UE on the search space corresponding to the ControlResourceSet with a CORESETPoolIndex value of 1 is the PDCCH order for TAG-1, and the random access procedure triggered by it is the random access procedure for TAG-1. The PDCCH order detected and received by the UE on the search space corresponding to the ControlResourceSet with a CORESETPoolIndex value of 0 is the PDCCH order for TAG-2, and the random access procedure triggered by it is the random access procedure for TAG-2.

[0175] Method 2: Determine through TCI state.

[0176] For example, if the UE receives a PDCCH order on an activated TCI state, the corresponding TRP is the TRP configured with the TCI state, or the corresponding TAG is the TAG configured or associated with the TCI state. The random access procedure triggered by this PDCCH order is a random access procedure for the TRP or TAG associated with the TCI state.

[0177] It is also possible to determine the TRP or TAG corresponding to the PDCCH order according to the TCI state indicated in the received DCI format for the PDCCH order and its associated TRP or TAG, and then determine the TRP or TAG for the random access process triggered by the PDCCH order.

[0178] Or all TCI states configured by the UE can be divided into several groups or sets, each of which can correspond to a TRP or TAG. Then the TRP or TAG can be determined according to the TCIstate set to which the TCI state indicated in the received DCI format for the PDCCH order belongs. Or the TRP or TAG can be determined according to the TCIstate set to which the TCIstate used to receive the PDCCH belongs, and then the TRP or TAG for the random access process triggered by the PDCCH order is determined.

[0179] Method 3: Direct Instruction

[0180] The DCI format used for the PDCCH order carries indication information, indicating the TRP / TAG corresponding to the PDCCH order. For example, when the value of the TRP field is set to 0, it corresponds to TRP-1, and when the value is 1, it corresponds to TRP-2.

[0181] Specifically, it can be determined based on the indication information carried in the DCI format used for the PDCCH order, for example, the PDCCH order indicates the identification information corresponding to the TRP, such as '0' represents the first TRP, or the primary TRP, and '1' represents the second TRP or the secondary TRP. It can also be information indicating the TAG ID associated with the service cell. Since a service cell configured with multiple TRPs can be associated with at least two TAGs, the TAG identification (TAG ID) information can be directly indicated in the PDCCH order to determine the corresponding TRP or TAG. In the case of only two TAGs, '0' can also be used to represent the first TAG, which can be the ID number or the TAG ID with a smaller value; '1' can be used to represent the second TAG, which can be the ID number or the TAG ID with a larger value, to determine the corresponding TRP or TAG. It can also indicate the added cell physical ID (additionalPCI). When the ID appears, it corresponds to one of the TRPs (or TAGs), and when the ID does not appear, it corresponds to another TRP (or TAG). Therefore, the random access process triggered by the PDCCH order is triggered by the PDCCH order indicating TRP or TAG related information.

[0182] In addition, it can also be implicitly indicated, for example, the RACH access resources (which may include a preamble sequence, or SSB, etc.) will be indicated in the PDCCH order. If these access resources are pre-configured and associated with a certain TAG or TRP, it also means that the PDCCH order is oriented to the TRP or TAG of the serving cell to trigger or start the random access process, or that the TRP or TAG related information is indicated in the PDCCH order, so the triggered random access process is triggered by the PDCCH order indicating the TRP or TAG related information.

[0183] In addition to the above methods, this article does not restrict the UE from determining the TRP or TAG corresponding to the PDCCH order through other methods.

[0184] Example 7

[0185] If the random access resources selected by the UE (including the selected random access channel, preamble sequence, SSB, CSI-RS, etc.) are associated with a certain TRP or TAG during the random access process, it can be considered that the random access process is associated with the TRP or TAG. This association relationship can be achieved through a configuration relationship, such as configuring the SSB to be associated with a certain TRP or TAG, or configuring the SSB to be associated with a certain CORESETPoolIndex value, and then the association between the SSB and the TAG can be determined through the association relationship between the CORESETPoolIndex value and the TAG.

[0186] In the above case, the condition in the above embodiment, "if the random access procedure for sending the preamble sequence on the SpCell is triggered by a PDCCH order for the TRP or TAG associated with the SpCell, or by a PDCCH order indicating TRP or TAG related information," can be replaced by the following condition:

[0187] "If the random access process of sending the preamble sequence on the SpCell is associated with a certain TRP or TAG."

[0188] The TAG associated with the random access process is the first TAG, and the other TAG associated with the Spcell is the second TAG.

[0189] Alternatively, it can be considered that the random access process triggered by the PDCCH order for the TRP or TAG associated with the SpCell, or triggered by the PDCCH order indicating TRP or TAG related information is also a random access process associated with a certain TRP or TAG, and then the aforementioned implementation plan is executed.

[0190] Figure 6 It is a brief structural block diagram of the user equipment involved in the present invention.

[0191] like Figure 6 As shown, the user equipment 600 includes at least a processor 601 and a memory 602. The processor 601 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 602 may include, for example, a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory systems, etc. Program instructions are stored on the memory 602. When the instructions are executed by the processor 601, one or more steps of the processing method of the UE disclosed in the present invention may be executed.

[0192] The method and the related equipment of the present disclosure have been described above in conjunction with the preferred embodiments. It can be understood by those skilled in the art that the method shown above is only exemplary, and the embodiments described above can be combined with each other without contradiction. The method of the present invention is not limited to the steps and sequence shown above.

[0193] The user equipment shown above may include more modules, for example, modules that can be developed or developed in the future and can be used for base stations, MMEs, or UEs, etc. The various identifiers shown above are only exemplary and not restrictive, and the present disclosure is not limited to the specific information elements used as examples of these identifiers. Those skilled in the art may make many changes and modifications based on the teachings of the illustrated embodiments.

[0194] It should be understood that the above embodiments of the present disclosure can be implemented by software, hardware, or a combination of software and hardware. For example, the various components inside the base station and user equipment in the above embodiments can be implemented by a variety of devices, including but not limited to: analog circuit devices, digital circuit devices, digital signal processing (DSP) circuits, programmable processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic devices (CPLDs), and the like.

[0195] In addition, the program running on the device according to the present invention can be a program that enables a computer to implement the functions of the embodiments of the present invention by controlling a central processing unit (CPU). The program or the information processed by the program can be temporarily stored in a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory systems.

[0196] The program for realizing the functions of various embodiments of the present invention can be recorded on a computer-readable recording medium. The corresponding functions can be realized by making a computer system read the program recorded on the recording medium and executing these programs. The so-called "computer system" herein can be a computer system embedded in the device, and can include an operating system or hardware (such as a peripheral device). "Computer-readable recording medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium of a short-term dynamic storage program, or any other recording medium that is computer-readable.

[0197] The various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., single-chip 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. The 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 the case where new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present invention may also be implemented using these new integrated circuit technologies.

[0198] In addition, the present invention is not limited to the above-mentioned embodiments. 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.

[0199] As mentioned above, the 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 changes that do not deviate from the main purpose of the present invention. In addition, the present invention can be modified in various ways within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. In addition, the components with the same effect described in the above embodiments can be replaced with each other.

Claims

1. A method performed by a user equipment UE, comprising: The UE starts a random access process; During the execution of the random access procedure, when the number of transmissions of the preamble sequence exceeds the transmission number threshold, the UE determines whether the random access procedure is triggered by a physical downlink control channel command PDCCH order for a TRP or TAG associated with a special cell SpCell; In a case where the UE determines that the random access procedure is triggered by the PDCCH order for a TRP or TAG associated with the SpCell, the UE performs at least one of the following operations: Stopping a TA timer associated with a first TAG among at least two TAGs associated with the SpCell; and It is determined that the random access procedure is not successfully completed.

2. The method according to claim 1, wherein: If the value of the variable PREAMBLE_TRANSMISSION_COUNTER is equal to the value of the parameter preambleTransMax plus 1, it means that the number of times the preamble sequence is sent exceeds the sending number threshold.

3. The method performed by a user equipment UE according to claim 1 or 2, wherein: The first TAG is a TAG for which a random access procedure triggered by the PDCCH order is directed.

4. The method performed by a user equipment UE according to claim 1 or 2, wherein: In a case where the UE determines that the currently initiated random access procedure is not triggered by the PDCCH order, the UE indicates a random access problem to an upper layer of a media access control MAC layer.

5. The method performed by a user equipment UE according to claim 1 or 2, wherein: The at least two TAGs further include a second TAG associated with the SpCell, In a case where the UE determines that the random access procedure is triggered by the PDCCHorder for the TRP or TAG associated with the SpCell, the UE further determines whether a TA timer associated with the second TAG is running, In a case where the TA timer associated with the second TAG is running, the UE performs at least one of the following operations: Stopping a TA timer associated with the first TAG; It is determined that the random access procedure is not successfully completed.

6. The method performed by the user equipment UE according to claim 5, wherein: In a case where the TA timer associated with the second TAG is not running, the UE performs the following operations: The random access problem is indicated to an upper layer of the MAC layer of the UE.

7. The method performed by a user equipment UE according to claim 1 or 2, wherein: In the case where the UE determines that the random access procedure is triggered by the PDCCHorder for the TRP or TAG associated with the SpCell, the UE further determines whether the value of the variable RA PROBLEM OCCUR is true, When the value of the variable RA PROBLEM OCCUR is true, the UE performs the following operations: The random access problem is indicated to an upper layer of the MAC layer of the UE.

8. The method performed by the user equipment UE according to claim 7, wherein: When the value of the variable RA PROBLEM OCCUR is false, the UE performs at least one of the following operations: Set the value of the variable RA PROBLEM OCCUR to true; Stopping a TA timer associated with the first TAG; It is determined that the random access procedure is not successfully completed.

9. The method performed by the user equipment UE according to claim 5, wherein: In a case where the TA timer associated with the second TAG is running, the UE performs at least one of the following operations: Stopping a TA timer associated with the first TAG; Determining that the random access procedure is not successfully completed; and Set the variable RA PROBLEM OCCUR to true. In a case where the TA timer associated with the second TAG is not running, the UE further determines whether the value of the variable RAPROBLEM OCCUR is true, If the value of RA PROBLEM OCCUR is true, the UE indicates a random access problem to an upper layer of the MAC layer; If the value of RA PROBLEM OCCUR is false, the UE initiates a random access procedure.

10. A user equipment, comprising: processor; as well as Memory, which stores instructions, Wherein, the above instructions, when executed by the above processor, execute the method according to any one of claims 1 to 9.

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