CN117377118A

CN117377118A - Method executed by user equipment and user equipment

Info

Publication number: CN117377118A
Application number: CN202210727514.1A
Authority: CN
Inventors: 张崇铭; 刘仁茂; 山田升平
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2022-06-23
Filing date: 2022-06-23
Publication date: 2024-01-09
Also published as: WO2023246765A1

Abstract

The invention provides a method executed by user equipment and the user equipment, wherein the method comprises the following steps: the User Equipment (UE) receives a Physical Downlink Control Channel (PDCCH) command from a base station and triggers a random access process; when a PDCCH command is received, under the condition that a service cell in which the UE is positioned is configured with a plurality of transmitting and receiving nodes TRPs and a time advance TA value corresponding to each TRP is independent, the UE determines the TRP corresponding to the PDCCH command; and the UE performs random access resource selection according to the determined TRP.

Description

Method executed by user equipment and user equipment

Technical Field

The present 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

To further enhance the performance of uplink transmission and reception in NR technology, the third generation partnership project (3 GPP) is looking to study uplink transmissions under multiple transmitting and receiving nodes (TRP). In one serving cell, more than one transmitting and receiving node TRP may be arranged, with each TRP providing service to the same UE, as shown in fig. 1. The physical distances between different TRPs and the UE are different, so that the propagation delay is different, and the value of the time Advance (Timing Advance) adopted by the UE when the UE transmits aiming at the different TRPs is different. In the prior art, the UE receives a PDCCH order (PDCCH order) from the network layer, and may trigger a random access procedure, and obtain a valid TA value in the procedure, so as to update the timing advance maintained by the UE. In the prior art, the UE interacts with only one TRP on one serving cell, maintaining one TA value; with the introduction of multiple TRPs, how a UE maintains multiple TA values is a problem to be solved.

Disclosure of Invention

In order to solve the above-described problems, the present invention provides a method performed by a user equipment and a corresponding user equipment capable of efficiently maintaining a plurality of TA values to reliably perform uplink transmission under a plurality of TRPs even in a case where the UE is configured with a plurality of TRPs on one serving cell.

According to one aspect of the present invention, there is provided a method performed by a user equipment, comprising the steps of:

the User Equipment (UE) receives a Physical Downlink Control Channel (PDCCH) command from a base station and triggers a random access process;

when a PDCCH command is received, under the condition that a service cell in which the UE is positioned is configured with a plurality of transmitting and receiving nodes TRPs and a time advance TA value corresponding to each TRP is independent, the UE determines the TRP corresponding to the PDCCH command;

and the UE performs random access resource selection according to the determined TRP.

In the method performed by the user equipment, the method preferably further includes the following steps:

based on the determined TRP, a proprietary random access resource associated with the determined TRP is selected for the triggered random access procedure.

According to the determined TRP, SSB or CSI-RS associated with the determined TRP is selected for the triggered random access process, and the value of a random access parameter PREAMBLE sequence number PREABLE_INDEX is set to be equal to the PREAMBLE sequence number corresponding to the selected SSB or CSI-RS.

In the above-described method performed by the user equipment, preferably,

the UE performs selection of the random access resource according to the determined TRP only when the determined TRP is the secondary TRP.

in the random access process started by the UE, when the number of times of PREAMBLE TRANSMISSION is equal to the value of the maximum allowed PREAMBLE TRANSMISSION times plus 1, namely, when the variable preamble_transmission_counter is equal to the value of the parameter preambbleTransMax plus 1,

if the random access procedure is triggered by a PDCCH order, and the triggered PDCCH order is associated with a determined TRP, the UE indicates a random access problem to an upper layer, and indicates that the random access is triggered by a PDCCH order from a certain TRP;

if the random access procedure is triggered for or associated with a determined TRP, the UE indicates a random access problem to an upper layer and indicates that the random access is triggered for or associated with the TRP;

When the upper layer of the UE receives the random access problem indication from the lower layer, the UE determines that the radio link failure RLF is detected if the random access is not triggered by a PDCCH order from the TRP or is not triggered for the TRP.

if the random access procedure is triggered by a PDCCH order, and the triggered PDCCH order is associated with the determined TRP, the UE does not indicate a random access problem to an upper layer;

if the random access procedure is triggered for or associated with a TRP, the UE does not indicate a random access problem to an upper layer;

when the upper layer of the UE receives the random access problem indication from the lower layer, the UE judges that the radio link failure RLF is detected.

for a random access procedure that is not successfully completed, if the random access procedure is triggered by a PDCCH order and the triggered PDCCH order is associated with a determined TRP, or if the random access procedure is triggered for or associated with a TRP, the UE generates a MAC CE in which information of the TRP associated with the random access is indicated, and information indicating that a random access failure occurs.

the TRP corresponding to the PDCCH command is determined by transmitting the configuration indication TCI state.

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

a processor; and

a memory in which instructions are stored,

wherein the instructions, when executed by the processor, perform the method described above.

According to the method performed by the user equipment and the corresponding user equipment, even if the UE is configured with a plurality of TRPs on one service cell, the plurality of TA values can be effectively maintained, so that uplink transmission under the plurality of TRPs can be reliably performed.

Drawings

Fig. 1 is a diagram illustrating uplink transmission under a plurality of transmitting and receiving nodes (TRPs).

Fig. 2 is a schematic diagram showing the time advance.

Fig. 3 is a flowchart showing a four-step random access procedure.

Fig. 4 is a flowchart showing a two-step random access procedure.

Fig. 5 is a flow chart illustrating a method performed by a user equipment according to an embodiment of the present invention.

Fig. 6 is a schematic block diagram of a user equipment according to the present invention.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description. It should be noted that the present invention should not be limited to the specific embodiments described below. In addition, for the sake of brevity, detailed descriptions of well-known techniques, which are not directly related to the present invention, are omitted to prevent confusion of the understanding of the present invention.

Before the detailed description, several terms mentioned in the present invention are explained as follows. Unless otherwise indicated, all terms used in the present invention have the following meanings.

UE: user Equipment;

NR: new Radio, new generation wireless technology;

LTE: long Term Evolution, long term evolution technology;

eLTE: enhaced Long Term Evolution, enhanced long term evolution technology;

RRC: radio Resource Control, radio resource control (layer);

MAC: medium Access Control, medium access control (layer);

MAC CE: MAC Control Element, MAC control element;

PHY: physical layer;

RB: a radio bearer;

DRB: data Radio Bearer, data radio bearer;

SRB: signalling Radio Bearer, signaling radio bearers;

TCI: transmission Configuration Indicator, transmitting a configuration indication;

DCI: downlink Control Information downlink control information

RSRP: reference Signal Received Power, reference signal received power;

PRACH: physical Random Access Channel physical random access channel;

PDCCH: physical Downlink Control Channel, physical downlink control channel;

RA: random Access;

RAR: random Access Response, random access response;

TRP: transmit/Receive Point, transmitting and receiving node;

SS: synchronization Signal, synchronization signal;

PBCH: physical Broadcast Channel, physical broadcast channel;

SSB: SS/PBCH block, synchronized broadcast block;

CSI-RS: channel State Information-Reference Signal channel state information Reference Signal.

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

Random access procedure Random Access procedure

The random access procedure includes a four-step random access procedure and a two-step random access procedure.

Four-step random access procedure

Hereinafter, a four-step random access procedure in the related art will be described first. The UE generally includes the following steps when performing a 4-step random access procedure.

Step 0: the UE selects a random access resource for random access. In this process

-the UE selecting a PREAMBLE sequence (PREAMBLE) for transmission, setting the sequence number corresponding to the selected PREAMBLE to the value of the parameter preamble_index; and

-determining a next PRACH occasion (determine the next available PRACH occasion from the PRACH occasions) available for transmission among a plurality of PRACH occasions (PRACH occlusions).

Step 1: the UE transmits the selected preamble on the determined PRACH occasion.

Step 2: the UE receives a random access response (Random Access Response, RAR) transmitted from the base station side.

If the sequence number (preamble index id) corresponding to the preamble sent by the UE in step 1 is carried in this RAR, the UE may determine that the RAR is to be sent to itself.

Such RAR carries an uplink grant (UL grant) and a time advance command (Timing Advance Command).

Wherein the UL grant indicates PUSCH resources for transmitting message 3. Timing Advance Command indicates a sequence number value (the index value T _A used to control the amount of timing adjustment)。

After receiving the RAR, the UE may apply Timing Advance Command to obtain a valid TA value. If this random access procedure is a non-contention based random access procedure, e.g. providing a proprietary preamble in the PDCCH order, then to this point the random access procedure is considered to be successful. If not, the UE may proceed to process the UL grant carried in the RAR and indicate it to the lower layer. If this is the first successful receipt of the above RAR by the UE, the UE obtains (obtain) the MAC PDU for transmission from the multiplexing and assembling entity (Multiplexing and assembly entity) and saves it in the buffer (MSG 3 buffer) of message 3.

Step 3: the UE sends message 3 on PUSCH resources indicated by the UL grant.

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

Step 4: the UE receives the message 4 sent from the base station side.

In the message 4, if the identification information carried by the UE in the message 3 is carried, the UE considers that the contention conflict is resolved, and the random access procedure is successfully completed.

Since the UE undergoes the message passing procedure of steps 1-4 in the random access procedure described above, it is called a "four-step random access" (4-step RA) procedure.

Two-step random access procedure

Next, the "two-step random access procedure" according to the present invention will be described in detail. The "two-step random access procedure" in the present invention generally includes the following steps.

-the UE selecting a PREAMBLE sequence (PREAMBLE) for transmission, setting the sequence number corresponding to the selected PREAMBLE to the value of the parameter preamble_index;

-determining a next PRACH occasion (determine the next available PRACH occasion from the PRACH occasions) available for transmission among a plurality of PRACH occasions (PRACH occalations); and

-determining PUSCH resources corresponding to the preamble sequence.

Step 1: the UE sends a message a (MSG a) to the base station.

Wherein, the message A contains a preamble and a payload (payload) of the message A.

Wherein, the preamble is sent on PRACH and the payload of message a is sent on PUSCH. The payload of message a is transmitted on PUSCH packaged as a MAC PDU. The payload of the message a may carry an RRC message, for example, an RRC connection establishment request message, and may also carry a user data packet.

Step 2: the UE receives a message B (MSG B) sent by the base station.

Wherein message B carries information for contention conflict resolution.

From the time sequence, the UE first transmits MSG a, including the load of transmitting preamble and transmitting message a; and then the UE receives the message B sent by the base station. Message B is response information of the network side/base station to the MSG a sent by the UE.

Further, when the UE determines a transmission opportunity available for message a, the UE acquires a MAC PDU for transmission from the multiplexing and assembling entity (Multiplexing and assembly entity) and saves the acquired MAC PDU in a buffer.

Since the message a includes the preamble sequence transmitted in the PRACH and the load information of the message a transmitted on the PUSCH, as the transmission timing available for the message a, for example, the following cases may be used as the transmission timing, including: the UE determines PUSCH occasions that can be used to transmit the payload of message a; or the UE determines the next available PRACH occasion which is used for transmitting the preamble sequence; or the UE selects a preamble sequence and the selected preamble sequence is used for the random access process; or the preamble sequence selected by the UE is associated with PUSCH or PUSCH occasion.

_TA Time advance N

Time advance N _TA May be used to calculate a time advance value (Timing advance between downlink and uplink) between upstream and downstream.

As shown in fig. 2, in order to maintain Uplink synchronization, the UE needs to start transmission of the i-th Uplink Frame (Uplink Frame i) a period of time before the start position of the i-th Downlink Frame (Downlink Frame i). This time may be defined by a time advance value T _TA Characterization, T _TA ＝(N _TA +N _TA，offset )*T _c Wherein T is _c Is a time parameter related to the carrier frequency.

Timing advance command includes an index value (T) _A For calculating N _TA . Upon receiving Timing advance command contained in the random access response, the UE may respond to T therein _A To calculate N _TA Is a value of (a). Or T _A Indirectly indicate N _TA Is a value of (2).

Time advance group (Timing Advance Group)

In the prior art, in order to maintain uplink time consistency (UL time alignment), each serving cell is divided into a TAG, and the serving cells with the same time advance belong to the same TAG. To manage the validity of the TA values, each TAG may have its own timer timeAlignmentTimer for controlling the validity time of the uplink synchronization of the Serving Cells (Serving Cells) belonging to that TAG. When the TA value is updated, the corresponding TAG timealignmentTimer is started or restarted; when the timeAlignmentTimer of a TAG runs out, it indicates that the uplink of the serving cell belonging to the TAG is no longer synchronized.

In the scenario of multiple TRPs, one serving cell may contain more than one TRP, each with its own corresponding time advance, then one embodiment may be that one serving cell may belong to more than one TAG, e.g. there may be two TAGs, each TAG corresponding to one TRP, or each TRP with its own associated TAG. Similarly, each TAG can have its own timealignmentTimer.

Yet another embodiment is that one serving cell belongs to one TAG, but this TAG has more than one TA value, e.g. one TAG may have at least two TA values, each TA value corresponding or associated with one TRP. Each TA that is similar may have its own timeAlignmentTimer, then the TAG may have multiple timealignmenttimers.

In this context, any of the manners described above may be employed for management of the TA.

In this context, since TRP and TAG/TA correspond to each other, the two expressions can be replaced with each other, for example, TRP corresponding to PDCCH order triggering random access is determined, and TAG corresponding to PDCCH order triggering random access is also determined accordingly.

PDCCH order (PDCCH order)

A proprietary DCI format is used to characterize PDCCH order, and such DCI is carried in PDCCH to trigger random access procedure. In such DCI formats, the sequence number (Random access preamble index) of the random access preamble sequence may be explicitly indicated, or the SS/PBCH sequence number may be explicitly indicated.

Synchronous broadcast block SSB

When the NR system works in the high frequency band, the base station often cannot simultaneously transmit a plurality of beams covering the entire cell, so a beam scanning technique is introduced into the NR system to solve the problem of cell coverage.

Beam scanning refers to that a base station only transmits one or several beam directions at a certain moment, and transmits all directions required for different beams to cover the whole cell at a plurality of moments. The set of synchronization broadcast blocks is designed for beam scanning and is used for transmitting a primary synchronization signal, a secondary synchronization signal and a physical broadcast channel required for searching a cell by the UE in each beam direction, and these signals constitute one synchronization broadcast block (SSB). The synchronous broadcast block set is a set of a plurality of synchronous broadcast blocks within a certain time period, each synchronous broadcast block corresponds to a beam direction within the same period, and the beam directions of the synchronous broadcast blocks of one synchronous broadcast block set cover the whole cell.

In a multiple TRP scenario, one TRP may be considered to correspond to a part of SSBs in the set of synchronized broadcast blocks, while another TRP corresponds to a part of SSBs in the set, both SSBs corresponding to the same constituting the complete set of synchronized broadcast blocks, i.e. covering the whole cell. In the random access procedure, the UE needs to first determine the beam direction of the random access, i.e. determine the SSB, when selecting the random access resource.

In multiple TRP (multiple TRPs) scenarios, it is also possible that one primary TRP (primary TRP) corresponds to all SSBs of the set of synchronized broadcast blocks, so that coverage of the entire cell is achieved, while there are one or more secondary TRP (Secondary TRP), whose corresponding beam directions may be part of SSBs or be more sub-divided, and may be characterized by CSI-RS, i.e. correspond to the beam directions of CSI-RS.

The corresponding relationship between TRP and SSB or CSI-RS may be considered to exist or be related to each other.

This correspondence may be directly embodied in RRC configuration information, e.g. a TRP is configured with the sequence numbers of one or more SSBs that are associated with the TRP; also for example, one or more CSI-RSs are configured for a TRP, then the CSI-RSs are associated with the TRP. Such correspondence may also be characterized by indirect means, such as by TCI states (TCI states). The UE detects the PDCCH on a configured search space (search space). The configuration information for each search space includes information about the set of control resources (Control Resource Set, CORESET) used by the search space. The control resource set provides resource blocks in the frequency and time domains. Each control resource set is associated with a series of TCI states. Each TCI state contains at least one SSB or CSI-RS information. The control resource sets for the same search space may be numbered by coresetPoollindex, where a number of 0 may correspond to a first TRP or primary TRP, a number of 1 may correspond to a second TRP or secondary TRP, and so on. Therefore, the configuration of the TCI state of the resource set can be corresponding to the TRP corresponding to the resource set, so that the TRP and the SSB or the CSI-RS form a corresponding relation.

In this context, since TRP and TCI state or coresetpoolndex correspond to each other, the two expressions may be replaced with each other, for example, TRP corresponding to PDCCH order triggering random access is determined, and TCI state or coresetpoolndex corresponding to PDCCH order triggering random access is also determined accordingly.

Four-step random access procedure (4 step Random Access procedure,4-step RA)

The following description refers to the accompanying drawings, and in particular, as shown in fig. 3, the UE performing a 4-step random access procedure includes the following steps:

step S300: the UE selects a random access resource for random access. In this process

Step S301: the UE transmits the selected preamble on the determined PRACH occasion.

Step S302: the UE receives a random access response (Random Access Response, RAR) transmitted from the base station side.

If the sequence number (preamble index id) corresponding to the preamble transmitted by the UE in step S301 is carried in this RAR, the UE may determine that the RAR is transmitted to itself.

Such RAR carries a UL grant indicating PUSCH resources for transmitting message 3.

Timing Advance Command (timing advance adjustment indication) is also carried in the RAR, and includes a sequence number value (the index value T _A used to control the amount of timing adjustment) for indexing or corresponding to a valid uplink synchronization time advance TA. The UE receives such Timing Advance CommandThe time advance indicated therein is applied for the next uplink transmission.

After receiving the RAR, the UE may apply Timing Advance Command to obtain a valid TA value. If this random access procedure is a non-contention based random access procedure, e.g. a proprietary preamble is provided in the PDCCH order, then to this point the random access procedure is considered to be successful. If not, the UE may continue to perform the following steps.

Upon receiving the above-mentioned RAR, the UE processes the UL grant carried in the RAR and indicates it to the lower layer. If this is the first successful receipt of the above RAR by the UE, the UE obtains (obtain) the MAC PDU for transmission from the multiplexing and assembling entity (Multiplexing and assembly entity) and saves it in the buffer (MSG 3 buffer) of message 3.

If the UE does not receive the RAR within a predetermined time, the UE increases the value of the variable preamble_transmission_counter by 1, whose initial value is 0. If preamble_transmission_counter=preableTransMax+1, then the UE considers that the random access procedure is not successfully completed, and may indicate a random access problem to the upper layer. The variable preamble_transmission_counter is used for recording the number of times of PREAMBLE TRANSMISSION, and the parameter PREAMBLE TRANSMISSION max is a preconfigured value, and the value of the parameter PREAMBLE TRANSMISSION max represents the maximum allowed number of times of PREAMBLE TRANSMISSION.

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

Step S304: the UE receives the message 4 sent from the base station side.

If the UE does not receive the message 4 for a predetermined time, the UE increases the value of the variable preamble_transmission_counter by 1, the initial value of which is 0. If preamble_transmission_counter=preableTransMax+1, then the UE considers that the random access procedure is not successfully completed, and may indicate a random access problem to the upper layer.

Since the UE has undergone the message passing process of steps S301 to S304 in the above random access procedure, it is called a "four-step random access" (4-step RA) procedure.

The above four-step random access procedure may also be referred to as layer 1 random access (Type-1 layer 1 Random Access Procedure,type 1L1 RA) of the first Type. From the physical layer (also called layer 1, layer 1) perspective, the type 1L1 RA procedure involves at least transmission of a random access preamble sequence (or transmission called message one) on the PRACH, and transmission/reception of a random access response message (Random Access Response Message), the transmission of which is scheduled by the PDCCH and transmitted on the PDSCH; in addition, the type 1l1 RA procedure may further include PUSCH scheduled by uplink grant carried in random access response, and PDSCH for contention resolution (contention resolution) therewith.

Two-step random access procedure (2 step Random Access procedure,2-step RA)

The following description refers to the accompanying drawings, and in particular, as shown in fig. 4, the two-step random access procedure comprises the following steps:

step S400: the UE selects a random access resource for random access. In this process

-determining PUSCH resources corresponding to the preamble sequence.

Step S401: the UE sends a message a (MSG a) to the base station.

Wherein, the preamble is sent on PRACH and the payload of message a is sent on PUSCH. The payload of message a is transmitted on PUSCH packaged as a MAC PDU. When the UE determines the occasion for transmitting message a, if this is the first time the UE transmits MSG a, the UE acquires (obtain) the MAC PDU for transmission from the multiplexing and assembling entity (Multiplexing and assembly entity) and saves it in the buffer (MSGA buffer) of message a.

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

Wherein message B carries information for contention conflict resolution.

In the present invention, the network, the base station and the RAN are used interchangeably, and the network may be a long term evolution LTE network, a New radio access technology (New RAT, NR) network, an enhanced long term evolution LTE network, or other networks defined in a later evolution version of 3 GPP.

Specific examples will be given below to illustrate the treatment method of the present invention.

Example 1

This embodiment presents a method performed by a user equipment, as shown in fig. 5, comprising the following steps.

Step S501: the UE receives PDCCH order from the base station and triggers a random access process.

Step S502: when receiving the PDCCH order, when a serving cell in which the UE is located is configured with a plurality of transmitting and receiving nodes TRPs and a TA value corresponding to each TRP is independent, the UE determines the TRP corresponding to the PDCCH order.

Step S503: and the UE performs random access resource selection according to the determined TRP.

When receiving the PDCCH order, the UE may determine whether the PDCCH order is from a specific TRP.

In one case, the UE is configured with multiple TRPs in the serving cell, and the TA value corresponding to each TRP is independent (it can also be understood that the UE is configured with multiple TA values or multiple TAGs in the serving cell, which are mutually interchangeable hereinafter), then the UE needs to determine which TRP the PDCCH order is associated with or which TA value/TAG when receiving the PDCCH order.

In addition, in another case, the UE does not have the plurality of TRPs configured as described above in the serving cell, and the UE does not need to make the above-described determination.

After the above determination, the UE may determine a TRP corresponding to the PDCCH order, and may consider that the random access procedure triggered by the PDCCH order also corresponds to the TRP or is associated with the determined TRP.

The UE then makes a selection of random access resources (Random Access Resource selection).

If the sequence number of the RA preamble sequence is explicitly indicated in the PDCCH for PDCCH order, the UE selects the SSB indicated by the PDCCH order, and if the sequence number of the RA preamble sequence is not explicitly indicated in the PDCCH for PDCCH order, the UE further judges whether the exclusive random access resource is configured. In particular, the method comprises the steps of,

1. in one case, the number (RA-preambieindex) of the RA PREAMBLE is explicitly indicated in the PDCCH for PDCCH order indication, and the value of this explicitly indicated RA-preambieindex is not equal to 0b000000, then the UE may set the value of the parameter preamble_index in the random access procedure to the indicated RA-preambieindex, and select the SSB indicated in the PDCCH.

2. In one case, there is no explicit sequence number indicating the RA preamble sequence in the PDCCH for PDCCH order indication, or the sequence number of the indicated RA preamble sequence has a value of 0b000000, and the UE needs to select RA resources in other manners.

For example, the UE further determines whether a dedicated random access resource is configured, where the dedicated random access resource includes at least configuration information of a random access resource (content-free Random Access Resources) based on a non-contention conflict, and the configured random access resource is associated with the SSB or the CSI-RS.

2.1 in one case, the configured proprietary RACH resource is associated with TRP. Then based on the previously determined TRP, the UE first needs to select the proprietary random access resource associated with the determined TRP for resource selection of the triggered random access procedure. If the configured dedicated random access resource is associated with other TRPs, then it should not be used for the resource selection of this random access, since this triggered random access procedure is associated with a determined TRP. Then, in the proprietary random resource associated with the determined TRP, if there is an SSB (or CSI-RS) satisfying the level condition, one is selected from SSBs (or CSI-RS) satisfying the condition, and the value of the parameter preamble_index is set to ra-preableindex corresponding to the SSB (or CSI-RS).

2.2 in another case, the configured proprietary random access resource is not associated with TRP. Then, when the resource selection of the random access procedure is performed in the dedicated random access resource, the selected SSB (or CSI-RS) needs to satisfy another condition, in addition to the requirement in the foregoing level, that the SSB (or CSI-RS) needs to be associated with the determined TRP. Then, one of SSB (or CSI-RS) meeting the condition is selected, and the value of the parameter PREABLE_INDEX is set as ra-Preamble INDEX corresponding to the SSB (or CSI-RS).

3. In another case, the UE is not configured with the foregoing configured with the dedicated random access resource, or the SSB or CSI-RS that satisfies the condition is not found in the foregoing configured with the dedicated random access resource, then the UE needs to select the random access resource in another manner.

3.1 for example, in case the serving cell is configured with multiple TRPs, the UE may select a suitable SSB on the SSBs associated with the above-determined TRPs, by which is meant that the SSB at least meets the level value requirement; if there is no SSB satisfying the level value requirement, the UE may select any one SSB from the SSBs associated with the TRP determined previously. Accordingly, the UE may always select a PREAMBLE in Random Access Preambles group A and set the value of the parameter preamble_index to the sequence number (INDEX) of the selected PREAMBLE. Or selecting a PREAMBLE from the random access PREAMBLE sequence packet associated with the above-determined TRP, and setting the value of the parameter preamble_index as the sequence number (INDEX) of the selected PREAMBLE.

3.2 also for example, in case the serving cell is configured with multiple TRPs, the UE may select an appropriate CSI-RS on the CSI-RS associated with the TRP determined as described above. By appropriate is meant that the CSI-RS can meet the level value requirements. If there is no CSI-RS satisfying the level value requirement, the UE may select any one CSI-RS from among CSI-RSs associated with the TRP determined as described above.

-if the selected CSI-RS has a corresponding random access resource, the UE may set the value of the parameter preamble_index to the sequence number (INDEX) of the corresponding PREAMBLE according to its corresponding random access resource;

-if the selected CSI-RS has no corresponding random access resource, the UE may select an SSB coupled (quantized) with the CSI-RS. The leader sequence was then selected according to the manner described in 3.1.

Example 2

The difference from embodiment 1 is that the UE performs the operations in embodiment 1 only when the determined TRP is a second TRP, and the specific implementation is as follows:

the UE receives the PDCCH order and triggers a random access process.

Upon receiving the PDCCH order, the UE may determine whether the PDCCH order is from a specific TRP.

In one case, the UE is configured with at least two TRPs in the serving cell, and the TA value corresponding to each TRP is independent (it can also be understood that the UE is configured with multiple TA values or multiple TAGs in the serving cell, which are mutually replaceable hereinafter), then the UE needs to determine which TRP the PDCCH order is associated with or which TA value/TAG when receiving the PDCCH order. Taking two TRP as an example, one is called primary TRP and the other is called secondary TRP.

When the UE determines that the TRP corresponding to the PDCCH order is a primary TRP, the UE may perform operation one in performing random access resource selection. Additionally, in another case, the UE does not have the plurality of TRPs configured as described above in the serving cell, so the UE does not need to make the above-described determination, and the UE may perform operation one in making random access resource selection.

When the UE determines that the TRP corresponding to the PDCCH order is a secondary TRP, the UE may perform operation two in performing random access resource selection.

Operation one:

in one case, the RA PREAMBLE sequence number (RA-preambieindex) is explicitly indicated in the PDCCH order, and the value of this explicitly indicated RA-preambieindex is not equal to 0b000000, then the UE may set the value of the parameter preamble_index in the random access procedure to the indicated RA-preambieindex, and select the SSB indicated in the PDCCH order.

In one case, there is no explicit sequence number indicating the RA preamble sequence in the PDCCH order, or the sequence number of the indicated RA preamble sequence has a value of 0b000000, and the UE needs to select RA resources in other manners.

In the configured exclusive random resource, if there is an SSB (or CSI-RS) satisfying the level condition, one is selected from SSBs (or CSI-RS) satisfying the condition, and the value of the parameter preamble_index is set to ra-preambieindex corresponding to the SSB (or CSI-RS).

If the UE is not configured with the foregoing configured random access resource, or the SSB or CSI-RS that satisfies the condition is not found in the foregoing configured random access resource, the UE selects a suitable SSB on the SSB, where suitable means that the SSB at least satisfies the level value requirement; if there is no SSB satisfying the level value requirement, the UE may select any one SSB from all SSBs.

And (2) operation II: as shown in example 1, wherein the determined TRP is a secondary TRP.

Example 3

For UE-initiated random access procedures, if the variable preamble_transmission_counter is equal to the parameter PREAMBLE transitmax plus 1, (preamble_transmission_counter=preamble transitmax+1), the UE may indicate a random access problem to an upper layer (e.g., RRC layer) of the MAC layer of the UE (Random access problem).

If the random access procedure is PDCCH order triggered and the triggered PDCCH order is associated with a determined TRP, the UE may indicate a random access problem to an upper layer (Random access problem) and indicate that the random access is triggered by a PDCCH order from a certain TRP;

Or if the random access procedure is triggered for or associated with a determined TRP, the UE indicates a random access problem (Random access problem) to an upper layer and indicates that the random access is TRP-triggered or associated with a TRP;

in other cases, the UE may indicate the random access problem directly to the upper layer.

The upper layer of the UE, e.g. the RRC layer, receives an indication of a random access problem from the lower layer, and if the random access is not triggered by PDCCH order from TRP or is not triggered for TRP, the UE considers that a radio link failure is detected (consider radio link failure to be detected); otherwise, the UE does not consider RLF detected.

Or the upper layers of the UE, e.g. the RRC layer, receives an indication of a random access problem from the lower layers, except that the UE always considers that a radio link failure is detected in such a case that the random access is triggered by PDCCH order from TRP or is triggered for TRP.

Embodiment 3 may be used in combination with embodiments 1 and 2 or may be used alone to manage random access problems associated with TRP.

In particular, the UE may use different treatments for primary TRP and secondary TRP triggered random access.

For example, for a UE-initiated random access procedure, if the variable preamble_transmission_counter is equal to the parameter preambmantransmax plus 1, (preamble_transmission_counter=preambmantransmax+1),

if the random access is triggered by primary TRP, the UE indicates the random access problem directly to the upper layer; when the upper layer receives the indication, the upper layer considers that the radio link is detected to fail, so that the RRC connection reestablishment flow can be triggered;

if the random access is triggered by the secondary TRP, the UE indicates a random access problem triggered by the secondary TRP to an upper layer; the upper layer, upon receiving the indication, does not consider that a radio link failure was detected.

That is, when the upper layer receives the random access problem indication from the lower layer, if the indication is not associated with or triggered by the second TRP, the UE considers that the radio link failure is detected.

Or when the upper layer receives the random access problem indication from the lower layer, the UE always considers that the radio link failure is detected except for the random access problem triggered by the secondary TRP.

Example 4

The difference from embodiment 3 is that when the UE judges the cause of triggering the random access procedure, if the random access procedure is PDCCH order-triggered and the triggered PDCCH order is associated with the determined TRP, the UE does not indicate a random access problem to an upper layer (Random access problem);

Or if the random access procedure is triggered for or associated with a TRP, the UE does not indicate a random access problem to an upper layer (Random access problem);

Additionally, the upper layers of the UE, such as the RRC layer, consider that a radio link failure is detected (Radio Link Failure) when receiving a random access problem indication from the lower layers.

Example 5

On the basis of embodiment 3 or 4, for the UE-initiated random access procedure, if the variable preamble_transmission_counter is equal to the parameter preableTransMax plus 1, (preamble_transmission_counter=preableTransMax+1), the UE considers that the random access procedure is not successfully completed (Random Access procedure unsuccessfully completed).

For a random access procedure that is not successfully completed, if the random access procedure is PDCCH order triggered and the triggered PDCCH order is associated with a determined TRP, or if the random access procedure is triggered for or otherwise associated with a TRP, the UE may generate a MAC CE in which information of the TRP associated with the random access may be indicated, and also information that a random access failure occurs may be indicated. The UE then transmits the MAC CE to the base station.

Example 6

In the foregoing embodiment, how the UE determines the TRP corresponding to the PDCCH order may be the following ways:

in one aspect, the search space for receiving the PDCCH is determined by the coreetpolindex corresponding to the control resource set to which the search space is configured.

For example, the PDCCH received by the UE on the search space corresponding to the control resource with value 0 of coresetpolindex may be TRP-1; and the corresponding TRP of the PDCCH received by the UE on the resource corresponding to coresetpoolndex value 1 on the search space may be TRP-2.

Or PDCCH received by UE on search space corresponding to coresetpolindex value 1 (such Coreset may be referred to as second Coreset), the corresponding TRP may be second TRP or second TRP; and the PDCCH received by the UE on the search space corresponding to the control resource (which may be referred to as the first Coreset) to which coresetpolindex is not assigned may be primary TRP or the first TRP.

Mode two, is determined by TCI state.

For example, the PDCCH received by the UE on the activated TCI state, the corresponding TRP is the TRP configured with the TCI state.

The TRP corresponding to the PDCCH order may be determined according to the TCI state indicated in the DCI format for the PDCCH order received.

Or all TCI states configured by the UE may be divided into several groups or sets, each of which may correspond to one TRP. The TRP may be determined from the set of TCI states to which it belongs, indicated in the DCI format for PDCCH order, received. Or determines TRP according to TCI state activation to which TCI state for receiving PDCCH belongs.

Mode three: direct indication

The DCI format used for the PDCCH order carries indication information, and indicates the TRP corresponding to the PDCCH order, for example, the TRP corresponds to TRP-1 when the value of the TRP domain is set to 0, and corresponds to TRP-2 when the value of the TRP domain is set to 1.

In addition to the above manner, the UE is not limited to determining the TRP corresponding to the PDCCH order in other manners herein.

As shown in fig. 6, the user equipment 600 includes at least a processor 601 and a memory 602. The processor 601 may include, for example, a microprocessor, microcontroller, embedded processor, or the like. The memory 602 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 systems. The memory 602 has stored thereon program instructions. The instructions, when executed by the processor 601, may perform one or more steps in a processing method of a UE of the present disclosure.

The method of the present disclosure and the apparatus involved have been described above in connection with the preferred embodiments. It will be appreciated by those skilled in the art that the methods shown above are merely exemplary and that the embodiments described above can be combined with one another without contradiction. The method of the present invention is not limited to the steps and sequences shown above.

The user equipment shown above may comprise further modules, e.g. modules that may be developed or developed in the future, available for a base station, MME, or UE, etc. The various identifiers shown above are merely exemplary and are not limiting, and the present disclosure is not limited to specific cells as examples of such identifiers. Many variations and modifications may be made by one of ordinary skill in the art in light of the teachings of the illustrated embodiments.

It should be understood that the above-described embodiments of the present disclosure may be implemented by software, hardware, or a combination of both software and hardware. For example, the various components within the base station and user equipment in the above embodiments may be implemented by a variety of means including, but not limited to: analog 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.

Further, the program running on the apparatus according to the present invention may be a program for causing a computer to realize the functions of the embodiments of the present invention by controlling a Central Processing Unit (CPU). The program or information processed by the program may be temporarily stored in a volatile store such as a random access memory RAM, a Hard Disk Drive (HDD), a nonvolatile store such as a flash memory, or other memory system.

A program for realizing the functions of the embodiments of the present invention may be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read programs recorded on the recording medium and execute the programs. The term "computer system" as used herein may be a computer system embedded in the device and may include an operating system or hardware (e.g., peripheral devices). The "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium in which a program is stored dynamically at a short time, or any other recording medium readable by a computer.

The various features or functional modules of the apparatus used in the embodiments described above may be implemented or performed by circuitry (e.g., single-chip or multi-chip integrated circuits). Circuits designed to perform the functions described herein may include a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The circuit may be a digital circuit or an analog circuit. Where new integrated circuit technologies are presented as an alternative to 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.

Furthermore, the present invention is not limited to the above-described 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 may be used as terminal devices or communication devices such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, vending machines, and other home appliances, etc.

As 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-described embodiment, and the present invention also includes any design modification without departing from the gist of the present invention. In addition, 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 the different embodiments are also included in the technical scope of the present invention. Further, the components having the same effects described in the above embodiments may be replaced with each other.

Claims

1. A method performed by a user equipment, comprising the steps of:

2. The method performed by a user equipment of claim 1, further comprising the step of:

3. The method performed by a user equipment of claim 1, further comprising the step of:

4. The method performed by a user equipment according to any one of claims 1 to 3, wherein,

5. A method performed by a user equipment according to any of claims 1 to 3, further comprising the step of:

in the random access process started by the UE, when the number of times of sending the preamble sequence is equal to the value of the maximum allowed preamble sequence sending times plus 1,

6. A method performed by a user equipment according to any of claims 1 to 3, further comprising the step of:

7. The method performed by the user equipment of claim 5, further comprising the step of:

8. The method performed by the user equipment of claim 6, further comprising the step of:

9. A method performed by a user equipment according to any of claims 1 to 3, further comprising the step of:

10. A user equipment, comprising:

a processor; and

a memory in which instructions are stored,

wherein the instructions, when executed by the processor, perform the method according to any one of claims 1 to 9.