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 user equipment UE receives a PDCCH order command sent by a base station or a network side, the PDCCH order command instructing the UE to execute a random access process in a candidate cell; after receiving the PDCCH order command, the UE determines a random access channel used for transmitting a preamble sequence / physical random access channel (PRACH) and the transmitted preamble sequence; the UE triggers a random access process based on the random access channel in a candidate cell and transmits the preamble sequence, and the UE judges whether the random access process is completed or not and discards the random access resource indicated in the PDCCH order command according to the judgment result.

Description

Technical Field

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

[0002] When a UE in an RRC connected state moves from the coverage area of ​​one cell to the coverage area of ​​another cell, in order to ensure service continuity, the base station or the network side usually instructs the UE to perform a cell switch (Cell Switch / Cell Handover) operation. The switch in the prior art is triggered by RRC signaling, that is, when the UE receives an RRC reconfiguration message carrying a synchronization identifier (here referred to as a layer 3 switch command), it will synchronize to the target cell specified in the message. The period from receiving the layer 3 switch command to completing synchronization with the target cell is called the switching delay. In the switching delay, the period of time that the UE initiates random access in the target cell to obtain uplink synchronization accounts for a large proportion of the switching delay.

[0003] In order to shorten the uplink synchronization time, a feasible method is to configure one or more candidate cells for the UE before the base station or the network instructs the UE to perform cell switching. Before performing the switching operation, the UE can perform uplink synchronization on this or these candidate cells in advance to obtain the transmission time advance of uplink synchronization. Such an operation can be achieved by the UE sending a preamble sequence to the candidate cell. The UE receives a PDCCH order (PDCCHorder) sent by the serving cell, which triggers the UE to send a preamble sequence to the candidate cell.

[0004] The existing PDCCH order triggers a random access process, in which the UE sends a preamble sequence to the target cell and receives a random access response message sent by the network side, and then sends the UE's third message on the uplink resources carried in the random access response message to resolve contention conflicts, and then receives the downlink control information (Downlink Control Information) or downlink assignment (Downlink Assignment) sent to the UE by the network side. In one case, the UE successfully completes the random access process, or the UE does not successfully complete the random access process. In either case, the random access process is considered to be completed, and the UE will discard the random access resources assigned to the UE in the PDCCH order when the random access is completed.

[0005] In order to obtain the transmission time advance of the uplink synchronization of the candidate cell, the UE may be triggered by the PDCCH order to perform a random access process for the candidate cell. In order to simplify the process, in such a random access process for the candidate cell, the UE will send a preamble sequence to the candidate cell, but will not receive a random access response message sent by the network side, as well as subsequent operations, as in the existing random access process triggered by PDCCH ordere.

[0006] Therefore, when the UE discards the random access resources assigned to the UE in the PDCCH order is a problem that needs to be solved. Summary of the invention

[0007] The purpose of the present disclosure is to provide a method executed by a user equipment and the user equipment.

[0008] According to a first aspect of the present disclosure, a method performed by a user equipment UE is provided, comprising: the user equipment UE receives a PDCCH order command sent from a base station or a network side, the PDCCH order command instructing the UE to perform a random access process in a candidate cell; after receiving the PDCCH order command, the UE determines a random access channel for sending a preamble sequence / physical random access channel PRACH, and a transmitted preamble sequence; the UE triggers a random access process based on the random access channel in the candidate cell, and transmits the preamble sequence, wherein the UE determines whether the random access process is completed, and discards the random access resources indicated in the PDCCH order command according to the determination result.

[0009] In the method of the first aspect above, preferably, the UE can start a timer V-order when receiving the PDCCH order command. If the timer V-order times out, it is determined that the random access process is completed and the random access resources indicated in the PDCCH order command are discarded.

[0010] In the method of the first aspect above, preferably, when the UE determines that a transmission conflict occurs, if the UE chooses to give up sending the preamble sequence in the candidate cell, or the UE chooses to continue uplink transmission on the serving cell, it is determined that the random access process is completed, and the random access resources indicated in the PDCCH order command are discarded.

[0011] In the method of the first aspect above, preferably, when the UE determines that a transmission conflict occurs, if the UE chooses to continue the random access process of the candidate cell, it is determined whether the random access process is completed based on whether the timer V-order has timed out.

[0012] In the method of the first aspect above, preferably, when the UE receives the PDCCH order command, it determines the transmit power of the preamble sequence. When the UE determines that the transmit power has reached or exceeded the maximum allowed transmit power value, the UE determines that the random access process is completed and discards the random access resources indicated in the PDCCH order command.

[0013] In the method of the first aspect above, preferably, after sending the preamble sequence, the UE determines that the random access procedure is completed and discards the random access resources indicated in the PDCCH order command.

[0014] In the method of the first aspect above, preferably, the PDCCHorder command also indicates at least one of the following information: random access resource information, including frequency information for determining a PRACH channel and / or time information for determining a PRACH channel; Random Access Preamble index random access preamble sequence number, the preamble sequence corresponding to the number will be used for the triggered random access process, or the preamble sequence sent to the candidate cell; carrier type, indicating that the RACH channel is located in the primary carrier or the secondary carrier; SS / PBCH index: indicating the sequence number used to determine the RACH timing.

[0015] In the method of the first aspect above, preferably, when the UE selects a preamble sequence for sending, the UE sets the sequence number corresponding to the selected preamble sequence to the value of the parameter PREAMBLE INDEX, determines the next PRACH opportunity that can be used for transmission among multiple PRACH opportunities, and the UE sends the selected preamble sequence on the determined PRACH opportunity.

[0016] 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.

[0017] Effects of the Invention

[0018] According to the method performed by the user equipment and the user equipment of the present disclosure, when performing a cell switching operation, it is possible to shorten the switching delay while ensuring the normal operation of the target cell after the switching, thereby improving the efficiency and quality of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 It is a flowchart showing a method executed by a user equipment UE involved in Embodiment 1 of the present disclosure.

[0021] Figure 2 is a block diagram showing a brief structure of a user equipment involved in the present disclosure.

[0022] It should be noted that the drawings are not necessarily drawn to scale, emphasis instead being placed on illustrating the principles of the technology disclosed herein. In addition, for clarity, like reference numerals throughout the drawings refer to like elements. DETAILED DESCRIPTION

[0023] The present disclosure is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the present disclosure 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 disclosure are omitted to prevent confusion in the understanding of the present disclosure.

[0024] Before the detailed description, some terms mentioned in the present disclosure are explained as follows. Unless otherwise specified, the terms involved in the present disclosure have the following meanings.

[0025] UE User Equipment

[0026] RLF Radio Link Failure

[0027] NR New Radio Next Generation Wireless Technology

[0028] LTE Long Term Evolution

[0029] Elte Enhaced Long Term Evolution

[0030] RRC Radio Resource Control

[0031] PDCP Packet Data Convergence Protocol1 Packet Data Convergence Protocol (layer)

[0032] RLC Radio Link Control, radio link control (layer)

[0033] MAC Medium Access Control Media Access Control (layer)

[0034] PHY physical layer

[0035] MAC CE Medium Access Control Control Element Media Access Control Layer Control Element

[0036] PDU Protocol Data Unit Protocol Data Unit

[0037] UE User Equipment

[0038] NR New Radio Next Generation Wireless Technology

[0039] HARQ Hybrid Automatic Repeat reQuest

[0040] DCI Downlink Control Information Downlink control information

[0041] SRB signaling radio bear

[0042] SS Synchronization Signal

[0043] PBCH Physical Broadcast Channel Physical Broadcast Channel

[0044] SSB SS / PBCH block Synchronous broadcast block

[0045] CSI-RS Channel State Information-Reference Signal Channel State Information Reference Signal

[0046] RSRP Reference Signal Received Power Reference signal received power

[0047] PRACH Physical Random Access Channel

[0048] PDCCH Physical Downlink Control Channel

[0049] PUCCH Physical Uplink Control Channel Physical Uplink Control Channel

[0050] PUSCH Physical Uplink Shared Channel Physical Uplink Shared Channel

[0051] RACH Random Access Channel Random Access Channel

[0052] LTM (Layer1 / Layer 2-triggered mobility, L1 / L2 triggered mobility)

[0053] LTM refers to the UE performing mobility operations upon receiving layer 1 / layer 2 signaling. Layer 1 / layer 2 signaling here refers to signaling for cell switching, which carries or indicates information about the target cell. The UE changes the serving cell by applying or executing the configuration information of the target cell.

[0054] Here, the target cell refers to the cell that will replace the current serving cell and provide services to the UE. The serving cell that provides services to the UE before receiving the handover signaling can be called the source cell. That is, after receiving the handover signaling, the UE will switch from the source cell to the target cell, and the target cell will continue to provide services to the UE. The movement of the UE leads to a change in the serving cell, which is triggered by L1 or L2.

[0055] The handover and cell change involved in this article are mainly the handover and cell change triggered by the LTM mentioned above.

[0056] LTM candidate cells

[0057] Before executing LTM, the UE will be configured with one or more candidate cells, one of which will become the target cell of LTM. The base station provides the UE with the configuration information of these candidate cells, which may be in the form of configuration information of a cell group, and numbers or sorts these candidate cells, each number or sequence number corresponds to a candidate cell, or the configuration information of a candidate cell can be determined. The configuration information may include at least the identification information of each candidate cell, such as the physical identification (Physical Cell ID, PCID) or cell ID of the cell, and may also include the channel configuration of the cell, such as the time frequency information of the PRACH channel, etc.

[0058] Cell group configuration

[0059] The configuration information of the cell group may include at least the configuration information of the MAC layer of the cell group, the configuration information of the physical layer, the configuration information of the primary serving cell (Spcell), and the configuration information of the optional secondary serving cell.

[0060] Since the configuration information of the candidate cells is included in the cell group configuration information, that is, the configuration information of the primary serving cell in the cell group configuration information can be used for the configuration of the candidate cells.

[0061] Therefore, in this article, the configuration information of the candidate cell and the configuration information of the cell group can be replaced with each other.

[0062] Preamble

[0063] In a random access procedure, the UE will send a preamble sequence on the transport channel RACH. This operation can also be considered as a PRACH transmission, where PRACH is the physical layer random access channel and its corresponding transport layer channel is RACH. The sent preamble sequence will be received by the base station. Since the base station can control the coverage of one or more cells, such a PRACH transmission is performed on one of the cells under the control of the base station.

[0064] In order to implement PRACH transmission, the UE needs to determine the PRACH channel of the target cell of the transmission, as well as the adopted preamble sequence and the transmission power of the preamble sequence.

[0065] In this article, the terms associated, corresponding, and relevant can be used interchangeably.

[0066] Since the UE needs to perform uplink or downlink synchronization (synchronization, sync) operations on the target cell when performing a cell change (Cell Switch), "cell change" in this article can also be replaced by "cell synchronization", that is, the switching command can be a message or instruction instructing the UE to synchronize the target cell.

[0067] The method executed by the user equipment of the present disclosure is described below in conjunction with an embodiment.

[0068] Example 1

[0069] use Figure 1 Embodiment 1 of the present disclosure will be described in detail. Figure 1 FIG. 1 is a flowchart schematically showing a method performed by a user equipment UE according to Embodiment 1 of the present disclosure. Figure 1As shown, this embodiment may include the following steps:

[0070] Step 1: The UE receives a command from the base station or the network side.

[0071] This command may trigger the UE to initiate a random access process, and such a random access process is performed in the candidate cell.

[0072] Alternatively, the command is a command instructing the UE to send (or transmit) a preamble sequence to the candidate cell, or a command instructing to send a PRACH.

[0073] The candidate cell here mainly refers to the candidate cell of LTM. Since the random access process triggered by the command will be performed on this candidate cell, it can be considered that this candidate cell is the target cell of the random access process to be performed, or the target cell to which the UE needs to send a preamble sequence / PRACH.

[0074] The candidate cell here is not the target cell of the handover, but a candidate cell that can be used as the target cell of the handover.

[0075] The candidate cell here is not a target cell when executing synchronous reconfiguration (execute reconfiguration with sync.), but a candidate cell that can be used as a target cell for executing synchronous reconfiguration in the future.

[0076] There can be one or more candidate cells. Each time the UE receives the above command, it performs random access or sends a preamble sequence / PRACH on the indicated candidate cell. The command indicates at least one candidate cell. If more than one candidate cell is indicated, the UE needs to perform random access or send a preamble sequence / PRACH on the indicated candidate cells respectively.

[0077] The base station can send the command to the UE in the form of DCI (Downlink Control Information). Since the content of DCI is transmitted on the PDCCH channel, such a command is called a PDCCH order. The PDCCH order (or the DCI indicating the command) can also indicate the information of the candidate cell, such as the index or identity of the cell configuration information of the candidate cell, or the identification information corresponding to a candidate cell configuration. Thus, the UE can determine that this is a random access process performed in the candidate cell.

[0078] In addition, at least one of the following information may also be indicated in the PDCCH order:

[0079] Random access resource information: may include frequency information for determining a PRACH channel and / or time information for determining a PRACH channel;

[0080] Random Access Preamble index: The preamble sequence corresponding to this number will be used for the triggered random access process, or the preamble sequence sent to the candidate cell;

[0081] Carrier type: indicates whether the RACH channel is located on the primary carrier or the secondary carrier;

[0082] SS / PBCH index: indicates the number used to determine the RACH occasion.

[0083] In addition, the PDCCHorder may also indicate information for determining the initial transmission (first transmission) or retransmission (retransmission, which may be the second, third, or fourth transmission) of the preamble sequence.

[0084] Step 2: After receiving the command, the UE can determine the random access channel used to send the preamble sequence / PRACH and the transmitted preamble sequence. The UE can determine the target cell according to the information of the candidate cell indicated in the command, and determine the random access channel on the target cell according to the random access resource indicated in the command, and can also determine the preamble sequence used for sending according to the preamble sequence number indicated in the command.

[0085] Step 3: The UE transmits a preamble sequence on the random access channel determined according to the above method, which may specifically include:

[0086] 3.1UE selects random access resources for random access. In this process, it can be

[0087] -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; wherein the value of the parameter may be equal to the aforementioned Random Access Preamble Index;

[0088] -If there are multiple PRACH occasions, the UE determines the next available PRACH occasion from the PRACH occasions.

[0089] 3.2UE sends the selected preamble at the determined PRACH timing,

[0090] The PDCCH order in step 1 is received by the UE on the serving cell, and the PRACH of the candidate cell indicated therein is located in the candidate cell. From a temporal point of view, there is a gap between the two. That is, the UE receives the PDCCH order from the serving cell at time T1 and sends the preamble sequence on the candidate cell at time T2. T1 is not equal to T2, and T1 is earlier than T2.

[0091] A possible implementation method may be that when the UE receives the PDCCH order shown in step 1, it starts a PDCCH order validity timer V-order to determine the validity period of the currently received PDCCH order. Then, when the timer V-order times out, it can be considered that the random access process is over, and the UE can discard the random access resources indicated in the PDCCH order.

[0092] Another possible implementation is that the UE can determine before time T2 (including time T1) that the PRACH channel of the candidate cell and the uplink transmission of the UE in the serving cell, at least including the transmission on the PRACH channel, PUCCH or PUSCH channel in the serving cell, may conflict (collision / overlap), and such conflict can be in time or frequency. For example, the transmission resources determined by the UE on the PRACH channel of the candidate cell overlap with the transmission resources of the UE on the PUCCH channel of the serving cell, for example, one or more symbols of these resources overlap; for example, the time interval between the two is too short to support the UE to switch from one transmission resource to another, etc., which can be regarded as sending conflicts.

[0093] In the case of determining that a conflict occurs, the UE may choose to continue the random access process of the candidate cell, thereby giving up the uplink transmission on the serving cell; or the UE may choose to give up sending the preamble sequence in the candidate cell (i.e., end the random access process in the candidate cell), thereby ensuring that the uplink transmission on the serving cell continues. When the UE chooses to give up sending the preamble sequence in the candidate cell or ends the random access process in the candidate cell, or chooses to continue uplink transmission on the serving cell, it can be considered that the random access process triggered by the UE in the candidate cell is completed (or ended, complete), preferably, it can be considered as an unsuccessful completion (or unsuccessfully ended, unsuccessfully complete), then the UE can discard the random access resources indicated in the PDCCH order at this time.

[0094] The above operation of determining transmission conflict needs to be performed after determining the random access resource, and thus can be performed before the aforementioned step 3, preferably after determining the random access resource in step 2, which is not limited here.

[0095] Another possible implementation is that the UE determines the transmit power of the preamble sequence when receiving the PDCCH order. When the UE determines that the transmit power has reached or exceeded the maximum allowed transmit power value, it can be considered that the random access process triggered by the UE in the candidate cell is completed, preferably, it can be considered as an unsuccessful completion, and the UE can discard the random access resources indicated in the PDCCH order at this time.

[0096] There are multiple methods for the UE to determine whether the transmit power reaches or exceeds the maximum allowed transmit power value, which may be a direct or indirect determination.

[0097] Direct judgment means that after the UE determines or calculates the current transmission power, it compares it with the pre-configured maximum allowed transmission power value. If it does not exceed the pre-configured allowed transmission power value, then the random access process can be continued and the preamble sequence can be transmitted; if it is equal to or greater than the pre-configured allowed transmission power value, then the UE can consider that the random access process triggered by the UE in the candidate cell is completed.

[0098] Indirect judgment refers to determining whether the maximum allowed transmit power is exceeded by other means. For example, the PDCCH order may also indicate information about initial transmission or retransmission. When the UE receives information indicating initial transmission, a variable COUNT may be set to a value of 1; when the UE receives information indicating retransmission, the value of the variable COUNT may be set plus 1. This COUNT can be used to calculate the transmit power of the preamble sequence. The network side may pre-configure the maximum value of the variable COUNT, for example, by broadcasting the maximum value to the UE in the system information or by including the configuration information of the candidate cell sent to the UE. When the value of COUNT is equal to or greater than the maximum value, it may indirectly indicate that the transmit power has reached or exceeded the maximum allowed transmit power value. In this way, the UE can indirectly determine whether the power has reached or exceeded the maximum value based on the value of the COUNT. The above implementation method may be: the UE receives the PDCCH order, determines the value of COUNT, for example, adds 1 to the COUNT value according to the retransmission indication information therein, or sets the COUNT value to 1 according to the initial transmission indication information therein, and then determines whether the COUNT value is greater than or equal to a pre-configured maximum value. If the COUNT value is greater than or equal to the pre-configured maximum value, then it can be considered that the random access process triggered by the UE in the candidate cell is completed, preferably, it can be considered as an unsuccessful completion, and then the UE can discard the random access resources indicated in the PDCCH order at this time.

[0099] As a supplement, if COUNT is not greater than or less than a preconfigured maximum value, the UE may transmit a preamble sequence.

[0100] The above power determination operation needs to be performed before sending the preamble sequence, and thus can be performed before the aforementioned step 3, after receiving the PDCCH order in step 1, or when determining the random access resource in step 2, which is not limited here.

[0101] Before executing step 1, the UE needs to be configured with relevant information of the candidate cells, so that the UE can determine the candidate cells and their corresponding configuration information according to the instructions in the command.

[0102] Example 2

[0103] Based on Embodiment 1, the UE may also discard the random access resources indicated in the PDCCHorder after executing step 3 to send the preamble sequence. That is, the UE may determine that the random access is completed after sending the preamble sequence in step 3, and discard the random access resources indicated in the PDCCHorder.

[0104] Example 3

[0105] In the aforementioned embodiment, the UE may perform the operation of discarding the random access resource after deeming that the random access is completed (or ended). Alternatively, the UE may not need to determine whether the random access is completed (or ended), but directly perform the operation of discarding the random access resource at the moments of "timer V-order operation timeout", "giving up sending the preamble sequence in the candidate cell", and "COUNT value is greater than or equal to the pre-configured maximum value", etc., where the discarded random access resource is the random access resource indicated in the PDCCH order.

[0106] Figure 2 2 is a block diagram showing a simplified structure of the user equipment 20 involved in the present disclosure. Figure 2 As shown, the user device 20 includes a processor 201 and a memory 202. The processor 201 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 202 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, etc. The memory 202 stores program instructions. When the instructions are executed by the processor 201, the above-mentioned method (such as the method of executing the user device) described in detail in the present disclosure may be executed. Figure 1 ).

[0107] The program running on the device according to the present disclosure may be a program that enables a computer to implement the functions of the embodiments of the present disclosure by controlling a central processing unit (CPU). The program or information processed by the program may 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.

[0108] The program for realizing the functions of each embodiment of the present disclosure 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 readable by a computer.

[0109] The various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., monolithic or multi-chip integrated circuits). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. 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 disclosure may also be implemented using these new integrated circuit technologies.

[0110] In addition, the present disclosure is not limited to the above-mentioned embodiments. Although various examples of the embodiments have been described, the present disclosure is not limited thereto. Fixed or non-mobile electronic devices installed indoors or outdoors can be used as UE devices or communication devices, such as AV equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0111] As mentioned above, the embodiments of the present disclosure 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 disclosure also includes any design changes that do not deviate from the main purpose of the present disclosure. In addition, various changes can be made to the present disclosure 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 disclosure. In addition, the components with the same effect described in the above embodiments can be replaced by each other.

Claims

1. A method performed by a user equipment UE, include: The user equipment UE receives a PDCCH order command sent from a base station or a network side, where the PDCCH order command instructs the UE to perform a random access procedure in a candidate cell; After receiving the PDCCH order command, the UE determines a random access channel for sending a preamble sequence / physical random access channel PRACH, and a transmitted preamble sequence; The UE triggers a random access process based on the random access channel in the candidate cell and transmits the preamble sequence, The UE determines whether the random access process is completed, and discards the random access resources indicated in the PDCCHorder command according to the determination result.

2. The method according to claim 1, in, When the UE receives the PDCCH order command, it starts a timer V-order. If the timer V-order times out, it is determined that the random access process is completed, and the random access resources indicated in the PDCCH order command are discarded.

3. The method according to claim 1, in, In the case where the UE determines that a transmission conflict occurs, if the UE chooses to give up sending the preamble sequence in the candidate cell, or the UE chooses to continue uplink transmission on the serving cell, it is determined that the random access process is completed, and the random access resources indicated in the PDCCH order command are discarded.

4. The method according to claim 2, in, In the case where the UE determines that a transmission conflict occurs, if the UE chooses to continue the random access process of the candidate cell, whether the random access process is completed is determined based on whether the timer V-order has timed out.

5. The method according to claim 1, in, When receiving the PDCCH order command, the UE determines the transmit power of the preamble sequence, When the UE determines that the transmit power has reached or exceeded the maximum allowed transmit power value, the UE determines that the random access process is completed and discards the random access resources indicated in the PDCCH order command.

6. The method according to claim 1, in, After sending the preamble sequence, the UE determines that the random access process is completed, and discards the random access resources indicated in the PDCCHorder command.

7. The method according to claim 1, in, The PDCCH order command also indicates at least one of the following information: Random access resource information: including frequency information for determining a PRACH channel and / or time information for determining a PRACH channel; Random Access Preamble index: The preamble corresponding to this number will be used for the triggered random access process, or the preamble sent to the candidate cell; Carrier type: indicates whether the RACH channel is located on the primary carrier or the secondary carrier; SS / PBCHindex: indicates the sequence number used to determine the RACH timing.

8. The method according to claim 1, in, When the UE selects a preamble sequence for transmission, the UE sets the sequence number corresponding to the selected preamble sequence to the value of the parameter PREAMBLE INDEX. Determine the next PRACH opportunity that can be used for transmission among multiple PRACH opportunities, The UE sends the selected preamble sequence at the determined PRACH opportunity.

9. A user device, include: processor; as well as A memory storing instructions; When the instructions are executed by the processor, the user equipment is caused to perform the method according to any one of claims 1 to 8.

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