Transmission method and device for physical random access channel of non-serving cell

Abstract

Methods and systems are provided for enabling a terminal device to perform physical random access channel (PRACH) transmissions on a non-serving cell. In some embodiments, the method comprises the following steps: (1) the terminal equipment receives configuration information of a PRACH (Physical Random Access Channel) of one or more non-serving cells; (2) the terminal equipment receives the control signaling; (3) the terminal equipment determines a PRACH lead code and a PRACH opportunity according to the configuration information; and (4) the terminal equipment sends the PRACH preamble in the PRACH opportunity. And the control signaling instructs the terminal equipment to send the PRACH information to a first non-serving cell in the one or more non-serving cells.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 296,344, filed on January 4, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to transmission of a physical random access channel (PRACH). More specifically, a system and method are provided to enable a terminal device to perform PRACH transmission to a non-serving cell. Background Art

[0003] New radio (NR) and fifth generation (5G) communication systems support physical downlink control channel (PDCCH) order (PDCCH order) PRACH transmission. "PDCCH order PRACH transmission" is a mechanism by which a base station can order a terminal device to initiate a PRACH transmission. An example of this mechanism is that when a base station finds that the timing between the base station and the terminal device UE needs to be corrected, the base station can order the terminal device to send PRACH, and then the base station can measure the uplink timing.

[0004] In the NR / 5G system, the base station uses "DCI format 0_1" to trigger the PDCCH command PRACH transmission. The method 100 shown in Figure 1 shows a traditional process. In box 101, the base station provides the configuration of PRACH to the terminal device. In box 103, the base station sends "DCI format 1_0" to trigger PRACH transmission. In box 105, the terminal device then decodes "DCI format 1_0" and sends a PRACH preamble according to the indication information indicated in "DCI format 1_0". In box 107, the base station then detects the PRACH preamble. In box 109, the base station then sends a PRACH response to the terminal device.

[0005] The aforementioned conventional method cannot trigger the terminal device to send a PRACH preamble to a non-serving cell. Therefore, when the terminal device is connected to a serving cell, the terminal device cannot send any PRACH information to the non-serving cell. The above defects result in the terminal device needing to perform a random access process on the non-serving cell when the terminal device is instructed to switch to the non-serving cell. Because cell switching increases the latency of the entire system, it is inefficient and undesirable. Therefore, an improved system and method that can solve the above problems is desirable and beneficial. Summary of the invention

[0006] The present disclosure relates to systems and methods for enabling a terminal device to perform PRACH transmissions to non-service cells. In some embodiments, a terminal device (or user equipment (UE)) may be provided with a configuration of PRACH for one or more non-service cells. The base station (or "gNB") may then send a downlink control information (DCI) format to trigger PRACH transmissions to non-service cells. The DCI format is specifically designed to trigger PRACH transmissions to non-service cells. The base station may then indicate to the terminal device a timing advance value for the non-service cell (e.g., a timing advance command in a media access control (MAC) control element (CE) message). The terminal device may then perform PRACH transmissions to non-service cells based on the timing advance value.

[0007] Advantages of the present technology include, for example, that the present technology can significantly reduce the latency of inter-cell mobility (or cell switching). For example, before switching to a target cell (which is a non-service cell), the service cell (e.g., a base station) can trigger the terminal device to send the PRACH information of the terminal device to the target cell. With this arrangement, the terminal device can even obtain the uplink timing of the non-service cell before the terminal device switches to the target cell. Therefore, the latency of inter-cell mobility or cell switching can be reduced, and the overall system efficiency can be improved.

[0008] In some embodiments, the method may be implemented by a tangible, non-transitory, computer-readable medium having processor instructions stored thereon, which, when executed by one or more processors, cause the one or more processors to perform one or more aspects / features of the method described herein. In other embodiments, the method may be implemented by a system including a computer processor and a non-transitory computer-readable storage medium storing instructions, which, when executed by a computer processor, cause the computer processor to perform one or more actions of the method described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly describe the technical solutions in the embodiments of the present disclosure, the following briefly describes the drawings. The drawings only show some aspects or embodiments of the present disclosure, and ordinary technicians in this field can still deduce other drawings from these drawings without creative efforts.

[0010] FIG. 1 is a flow chart showing a conventional method used in the prior art.

[0011] Figure 2 is a schematic diagram of a wireless communication system according to one or more embodiments of the present disclosure.

[0012] Figure 3 is a schematic block diagram of a terminal device according to one or more embodiments of the present disclosure.

[0013] Figure 4 is a flow chart of a method according to one or more embodiments of the present disclosure.

[0014] Figure 5 is a flow chart of a method according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0015] In order to more clearly describe the technical solutions in the embodiments of the present disclosure, the following briefly describes the drawings. The drawings only show some aspects or embodiments of the present disclosure, and ordinary technicians in this field can still deduce other drawings from these drawings without creative efforts.

[0016] Figure 2 2 is a schematic diagram of a wireless communication system 200 according to one or more embodiments of the present disclosure. The wireless communication system 200 may implement the method discussed herein for enabling a terminal device to perform PRACH transmission on a non-serving cell. Figure 2 As shown, the wireless communication system 200 includes a first network device (or base station / cell) 201 and a second network device (or base station / cell) 207 .

[0017] Examples of the first network device 201 and the second network device 207 include a base transceiver station (BTS), a NodeB (NB), an evolved NodeB (eNB or eNodeB), a next generation NodeB (gNB or gNodeB), a wireless fidelity (Wi-Fi) access point (AP), etc. In some embodiments, the network devices 201 and 207 may include a relay station, an access point, a vehicle-mounted device, a wearable device, etc. The first network device 201 and the second network device 207 may include wireless connection devices for communication networks such as: global system of mobile communication (GSM) network, code division multiple access (CDMA) network, wideband CDMA (WCDMA) network, LTE network, cloud radio access network (CRAN), Institute of electrical and electronics engineers (IEEE) 802.11-based network (e.g., Wi-Fi network), Internet of things (IoT) network, device to device (D2D) network, next generation network (e.g., 5G network), future evolved public land mobile network (PLMN), etc. 5G system or network may be referred to as NR system or network.

[0018] exist Figure 2In the wireless communication system 200, the terminal device 203 is further comprised of a terminal device 203. The terminal device 203 may be a terminal user device for facilitating wireless communication. The terminal device 203 may be configured to wirelessly connect to a first network device 201 (via, for example, a wireless channel 205A) according to one or more corresponding communication protocols / standards. In a "cell-switch" event, the terminal device 203 may be switched to wirelessly connect to a second network device 207 (via, for example, a wireless channel 205B). Before the "cell-switch" event, the first network device 201 may be recorded as a "serving cell" and the second network device 207 may be recorded as a "non-serving cell". After the "cell-switch" event, the second network device 207 becomes a "serving cell" and the first network device 201 becomes a "non-serving cell".

[0019] The terminal device 203 may be mobile or fixed. The terminal device 203 may be a user equipment (UE), an access terminal, a user unit, a user station, a mobile site, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device. Examples of the terminal device 203 include a modem, a cellular phone, a smart phone, a wireless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, an IoT device, a device used in a 5G network, or a device used in a future evolving public land mobile network, etc. For illustrative purposes, Figure 2 Only two network devices 201 and 207 and one terminal device 203 are shown in the wireless communication system 200. However, in some cases, the wireless communication system 200 may include additional network devices 201 and / or terminal devices 203.

[0020] The first network device 201 (for example, as a serving cell) may instruct the terminal device 203 to send PRACH information to the second network device 207 (for example, as a non-serving cell). In some embodiments, the first network device 201 may provide the terminal device 203 with the PRACH configuration of one or more non-serving cells (including the second network device 207). The first network device 201 may send a first control signaling (for example, MAC CE, DCI, etc.) to instruct the terminal device 203 to send PRACH information to the second network device 207. When the first control signaling is received, the terminal device 203 is requested to send a PRACH preamble to the second network device 207 in a determined PRACH opportunity.

[0021] In some embodiments, based on an SS / PBCH of the indicated second network device 207, a random access channel (RACH) timing for PRACH transmission may be indicated to the terminal device 203. In some embodiments, the terminal device 203 may be requested to determine an uplink transmission configuration for transmitting a PRACH preamble based on the SS / PBCH of the indicated second network device 207. In some embodiments, the uplink transmission configuration may include a spatial transmit filter and / or an uplink transmit power.

[0022] When receiving the PRACH preamble from the terminal device 203, the first network device 201 determines a timing advance value for uplink transmission to the second network device 207. The first network device 201 may indicate the timing advance for uplink transmission to the second network device 207 to the terminal device 203.

[0023] In some embodiments, the first network device 201 may use "DCI format X" to trigger the terminal device 203 to send a PRACH preamble to a non-serving cell (e.g., the second network device 207). "DCI format X" may include one or more of the following bit fields: (1) an indicator indicating an identification (ID) of a cell; (2) an indicator of the SS / PBCH of the cell; (3) an indicator of a random access preamble index; and (4) an indicator of a PRACH mask index.

[0024] In some embodiments, the "indicator indicating a cell ID" may indicate a non-serving cell (e.g., the second network device 207), wherein the terminal device 203 is instructed to send a PRACH preamble to the non-serving cell. The "SS / PBCH indicator of the cell" may indicate the SS / PBCH of the non-serving cell (e.g., the second network device 207). The terminal device 203 may be requested to use the indicated SS / PBCH to determine the RACH timing for PRACH transmission. In some embodiments, the "indicator of the random access preamble index" may indicate a PRACH preamble for transmission by the terminal device 203. In some embodiments, the "indicator of the PRACH mask index" may be used to indicate the RACH timing for PRACH transmission.

[0025] In some embodiments, the first network device 201 may send a "DCI format 1_0" to trigger the terminal device 203 to send a PRACH transmission. In such an embodiment, the "DCI format 1_0" may include the following fields:

[0026] [i] Random Access Preamble index: In one example, this field may be 6 bits. This field may also indicate a RACH preamble index.

[0027] [ii]UL / SUL indicator: In one example, this field may be 1 bit. This field indicates which UL carrier in the network device is to transmit the PRACH.

[0028] [iii]Indicator of physical cell ID (PCI): This field indicates the serving cell in which the PRACH is to be transmitted.

[0029] [ iv]SS / PBCH index: This field may be 6 bits. This field may indicate an SS / PBCH of the serving cell indicated by the "indicator of physical cell ID", and the SS / PBCH may be used to determine the RACH timing of PRACH transmission.

[0030] [v] PRACH Mask index: This field may be 4 bits. This field may indicate the RACH opportunity associated with the SS / PBCH indicated by the "SS / PBCH index" of the PRACH transmission.

[0031] In some embodiments, "DCI format 1_0" may include the following fields:

[0032] [a] Random Access Preamble index: In one example, this field may be 6 bits. This field may indicate a RACH preamble index.

[0033] [b] UL / SUL indicator:In one example, this field may be 1 bit. This field indicates which UL carrier in the cell is to transmit the PRACH.

[0034] [c] SS / PBCH index: This field may indicate one SS / PBCH of a serving cell or a non-serving cell, which SS / PBCH is used to determine the RACH timing of PRACH transmission. For example, this field may be 8 bits, and one of the first "N1" values ​​of this field may indicate one SS / PBCH of one cell, and one of the next "N2" values ​​of this field may indicate one SS / PBCH of another cell.

[0035] [d] PRACH Mask index: This field may be 4 bits. This field may indicate the RACH opportunity associated with the SS / PBCH indicated by the "SS / PBCH index" of the PRACH transmission.

[0036] In some embodiments, the bit field of "DCI format 1_0" for triggering PRACH transmission may vary depending on whether the terminal device 203 is configured with inter-cell PDCCH commanding PRACH transmission. For example, if the terminal device 203 is not configured with inter-cell PDCCH commanding PRACH transmission, the "DCI format 1_0" for triggering PRACH transmission does not indicate the SS / PBCH of the non-serving cell. If the terminal device 203 is configured with inter-cell PDCCH commanding PRACH transmission, the "DCI format 1_0" for triggering PRACH transmission may indicate the SS / PBCH of the serving cell or the non-serving cell.

[0037] In some embodiments, the "DCI format 1_0" for triggering PRACH transmission to a non-serving cell may be scrambled with a dedicated radio network temporary identity (RNTI). For example, if the cyclic redundancy check (CRC) of the "DCI format 1_0" is scrambled by the first RNTI, the "DCI format 1_0" triggers PRACH transmission to the non-serving cell, and the "DCI format 1_0" may indicate information of a physical cell ID (e.g., showing to which cell the triggered PRACH transmission is to).

[0038] In some embodiments, a timing advance value of a non-serving cell (e.g., second network device 207) may be provided to terminal device 203. For example, first network device 201 may provide a timing advance command for second network device 207 to terminal device 203. When terminal device 203 switches to second network device 207, terminal device 203 may apply the provided timing advance command on uplink transmission to second network device 207.

[0039] In some embodiments, first network device 201 may provide a timing advance command for second network device 207 in a MAC CE message. In some embodiments, first network device 201 may provide a timing advance for second network device 207 in a response message to a PDCCH order PRACH transmission with a preamble sent to second network device 207.

[0040] In some embodiments, in the MAC CE message, the first network device 201 may provide one or more of the following information elements: an indicator indicating a physical cell ID, a timing advance group (TAG), a timing advance value, etc. In some embodiments, the terminal device 203 may use the timing advance value in the uplink transmission to the cell identified by the above-mentioned "indicator indicating a physical cell ID" field.

[0041] In some embodiments, the first network device 201 may first send PDCCH information to trigger a PDCCH command PRACH transmission to the first cell (e.g., the second network device 207). After decoding the PDCCH information, the terminal device 203 initiates a PRACH transmission as requested by the first network device 201. The first network device 201 may then detect the PRACH transmission and calculate the timing advance value. Thereafter, the first network device 201 may indicate the calculated timing advance value for the first cell to the terminal device 203, for example, via a MAC CE.

[0042] Figure 3It is a schematic block diagram of a terminal device 203 according to one or more embodiments of the present disclosure (for example, a method discussed herein can be implemented). As shown in the figure, the terminal device 203 includes a processor 310 (for example, a DSP, a CPU, a GPU, etc.) and a memory 320. The processor 310 can be used to implement instructions corresponding to the methods discussed herein and / or other aspects of the above-mentioned embodiments. It should be understood that the processor 310 in the embodiment of the present technology can be an integrated circuit chip and has signal processing capabilities. In the implementation process, each step in the above method can be implemented by using an integrated logic circuit of hardware in the processor 310 or an instruction in the form of software. The processor 310 can be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic device, a discrete gate or transistor logic device, and a discrete hardware component. The method, steps and logic block diagram disclosed in the embodiment of the present technology can be implemented or executed. The general-purpose processor 310 can be a microprocessor, or the processor 310 can be any conventional processor, etc. The steps in the method disclosed with reference to the embodiments of the present technology can be directly executed or completed by a decoding processor implemented as hardware, or by using a combination of hardware and software modules in the decoding processor. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, or other mature storage media in the art. The storage medium is located in the memory 320, and the processor 310 reads the information in the memory 320 and completes the steps in the above method in combination with the hardware of the memory 320.

[0043] It is understood that the memory 320 in the embodiment of the present technology can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. The non-volatile memory can be a ROM, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM) and the RAM is used as an external cache. For exemplary and non-limiting description, many forms of RAM can be used, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SyncLink Dynamic Random Access Memory, SLDRAM), direct memory bus random access memory (Direct Rambus Random Access Memory, DR RAM). It should be noted that the memory of the system and method described herein is intended to include, but is not limited to, these memories and any other suitable types of memory. In some embodiments, the memory can be a non-temporary computer-readable storage medium that stores instructions that can be executed by a processor.

[0044] Figure 44 is a flow chart of a method 400 according to one or more embodiments of the present disclosure. The method 400 is used to enable a terminal device to perform PRACH transmission on a non-serving cell. The method 400 may be implemented by a system (e.g., a wireless communication system 200). For example, the method 400 may also be implemented by the terminal device 203, the first network device 201, and / or the second network device 207.

[0045] The method 400 includes, at block 401, the terminal device receives configuration information of PRACH of one or more non-serving cells. At block 403, the method 400 continues, the terminal device receives a control signaling. The control signaling instructs the terminal device to send PRACH information to a first non-serving cell (eg, the second network device 207).

[0046] At block 405, the method 400 continues with the terminal device determining a PRACH preamble and a PRACH opportunity based on the configuration information. At block 407, the method 400 continues with the terminal device sending a PRACH preamble in a PRACH opportunity (to the first network device 201). In some embodiments, the first network device 201 then detects the PRACH preamble and can then determine the uplink timing of the terminal device 203 and the first non-serving cell.

[0047] At block 409, the method 400 continues with the terminal device receiving a PRACH response. The PRACH response indicates an uplink timing for the terminal device to switch to the first non-serving cell.

[0048] Figure 5 1 is a flow chart of a method 500 according to one or more embodiments of the present disclosure. The method 500 enables a terminal device to perform PRACH transmission on a non-serving cell. The method 500 may be implemented by a system (e.g., a wireless communication system 200). For example, the method 500 may also be implemented by the terminal device 203, the first network device 201, and / or the second network device 207.

[0049] The method 500 includes, at block 501, a base station (e.g., a first network device 201) sending configuration information of a PRACH of a first non-serving cell (e.g., a second network device 207) to a terminal device (e.g., a terminal device 203). At block 503, the method 500 continues, the base station sending a timing advance command to the terminal device. The timing advance command includes a first timing advance for uplink transmission to the first non-serving cell.

[0050] At block 505, method 500 continues with the base station sending a control command instructing the terminal device to switch to the first non-serving cell. In some embodiments, the control command may be a DCI. In some embodiments, the control command may be a MAC CE. The terminal device may then perform a cell switching process (or an inter-cell mobility event) and switch to the first non-serving cell. The terminal device may start performing uplink transmissions to the first non-serving cell according to the first timing advance. Other considerations

[0051] The above specific implementations of the examples of the disclosed technology are not intended to be exhaustive or to limit the disclosed technology to the precise form disclosed above. Although the specific examples of the disclosed technology are described above for illustrative purposes, as can be appreciated by those skilled in the relevant art, various equivalent modifications can be made within the scope of the described technology. For example, when the process or frame is presented in a specific order, other embodiments can perform routines with steps in different orders or adopt systems with frames, and can remove, move, add, subdivide, combine and / or modify some processes or frames to provide other embodiments or sub-combinations. Each of these processes or frames can be implemented in various different ways. In addition, although the process or frame is sometimes shown as being executed in series, these processes or frames can be executed or implemented in parallel, or can be executed at different times. In addition, any specific numbers described herein are only examples; other embodiments can adopt different values ​​or ranges.

[0052] In the specific embodiments, many specific details are set forth to provide a comprehensive understanding of the technology currently described. In other embodiments, the technology described herein can be implemented without these specific details. In other instances, in order to avoid unnecessarily obscuring the present disclosure, well-known features such as specific functions or routines are not described in detail. The reference to "implementation / embodiment", "one implementation / embodiment", etc. in the specification indicates that the specific features, structures, objects or characteristics described are included in at least one embodiment of the described technology. Therefore, the appearance of such phrases in the specification does not necessarily refer to the same implementation / embodiment. On the other hand, such descriptions are not necessarily mutually exclusive. In addition, specific features, structures, objects or characteristics can be combined in any suitable manner in one or more implementations / embodiments. It should be understood that the various implementations shown in the figures are merely illustrative representations and are not necessarily drawn to scale.

[0053] For the sake of clarity, some details describing structures or processes are not set forth herein, which are well known and commonly associated with communication systems and subsystems, but which may unnecessarily obscure some important aspects of the disclosed technology. In addition, although the following disclosure sets forth some embodiments of different aspects of the present disclosure, some other embodiments may have different configurations or different components than the embodiments described in this section. Therefore, the disclosed technology may have other embodiments with additional elements or without some of the elements described.

[0054] Many embodiments or aspects of the technology described herein can take the form of computer executable instructions or processor executable instructions, including routines performed by programmable computers or processors. It will be appreciated by those skilled in the relevant art that the described technology can be implemented on a computer or processor system other than those illustrated and described. The technology described herein can be implemented in a special-purpose computer or data processor, which is specially programmed, configured or constructed to perform one or more of the described computer executable instructions. Therefore, the terms "computer" and "processor" commonly used herein refer to any data processor. The information processed by these computers and processors can be presented on any suitable display medium. Instructions for performing computer executable tasks or processor executable tasks can be stored in or on any suitable computer-readable medium, including hardware, firmware, or a combination of hardware and firmware. Instructions can be included in any suitable memory device, including, for example, a flash drive and / or other suitable media.

[0055] The term "and / or" in this specification is only used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0056] These and other changes can be made to the disclosed technology in accordance with the above-described specific embodiments. Although the specific embodiments describe certain examples of the disclosed technology and the best mode considered, no matter how detailed the above description is in the text, the disclosed technology can be implemented in many ways. The details of the system may vary significantly in its specific implementation, but are still covered by the technology disclosed herein. As described above, specific terms used when describing certain features or aspects of the disclosed technology should not be taken as implying that the term is redefined herein to be limited to any specific characteristics, features, or aspects of the disclosed technology associated with the term. Therefore, the present invention is not limited except in the appended claims. In general, the terms used in the claims should not be understood to limit the disclosed technology to the specific examples disclosed in the specification unless the above-mentioned specific implementation section explicitly defines these terms.

[0057] Those skilled in the art will appreciate that, in conjunction with the examples described in the embodiments disclosed in this specification, the units and algorithm steps can be implemented with electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0058] Although certain aspects of the invention are presented below in certain claim forms, applicants recognize that the various aspects of the invention may take any number of claim forms. Applicants therefore reserve the right to issue additional claims in this or a continuation application after filing this application.

Claims

1. A method comprising: The terminal device receives configuration information of a physical random access channel (PRACH) of one or more non-serving cells; The terminal device receives control signaling, wherein the control signaling instructs the terminal device to send PRACH information to a first non-serving cell among the one or more non-serving cells; The terminal device determines a PRACH preamble and a PRACH timing according to the configuration information; and The terminal device sends the PRACH preamble code at the PRACH timing.

2. The method according to claim 1, wherein: The PRACH preamble code is sent to the serving base station in the PRACH opportunity.

3. The method according to claim 2, wherein: The terminal device receives the configuration information of the PRACH of the one or more non-serving cells from the serving base station.

4. The method according to claim 2, wherein: The terminal device receives the control signaling from the serving base station.

5. The method according to claim 2, wherein: The serving base station detects the PRACH preamble code.

6. The method according to claim 5, wherein: The serving base station determines the uplink timing of the terminal device according to the PRACH preamble code.

7. The method according to claim 5, wherein: The serving base station determines the first non-serving cell according to the PRACH preamble code.

8. The method according to claim 2, further comprising: The terminal device receives a PRACH response from the serving base station.

9. The method according to claim 8, wherein: The PRACH response indication is used for the uplink timing of the terminal device switching to the first non-serving cell.

10. The method according to claim 1, wherein: The control signaling includes downlink control information (DCI).

11. The method according to claim 1, wherein: The control signaling includes a Medium Access Control (MAC) Element (CE) message.

12. A method comprising: The base station sends configuration information of a physical random access channel (PRACH) of a first non-serving cell to the terminal device; The base station sends a timing advance command to the terminal device, wherein the timing advance command includes a first timing advance for uplink transmission to the first non-serving cell; The base station sends a control command instructing the terminal device to switch to the first non-serving cell.

13. The method according to claim 12, wherein: The control command includes downlink control information (DCI).

14. The method according to claim 12, wherein: The control command comprises a medium access control (MAC) element (CE) message.

15. The method according to claim 12, wherein: The timing advance command is determined based on a PRACH preamble received from the terminal device.

16. The method according to claim 15, further comprising: The base station determines the first non-serving cell from two or more non-serving cells according to the PRACH preamble code.

17. The method according to claim 15, further comprising: The uplink timing of the terminal device to the first non-serving cell is determined according to the PRACH preamble code.

18. A system comprising: processor; as well as A memory, the memory being used to store instructions, which when executed by the processor are used to: receiving configuration information of a physical random access channel (PRACH) of one or more non-serving cells; receiving control signaling, wherein the control signaling instructs the terminal device to send PRACH information to a first non-serving cell among the one or more non-serving cells; Determine a PRACH preamble and a PRACH timing according to the configuration information; and The PRACH preamble is sent in the PRACH opportunity.

19. The system of claim 18, wherein: The PRACH preamble code is sent to the serving base station in the PRACH opportunity.

20. The system of claim 18, wherein: The terminal device receives the control signaling from the serving base station, wherein the serving base station detects the PRACH preamble code, and wherein the serving base station determines the uplink timing of the terminal device to the first non-serving cell based on the PRACH preamble code.

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