Random access method and communication device

Abstract

A random access method and a communication device, the method may comprise: a terminal device sends a message 1 to a network device, the message 1 being associated with a first reference signal; the network equipment sends a message 2 to the terminal equipment, wherein the message 2 is associated with the first reference signal; the terminal equipment sends a message 3 to the network equipment, wherein the message 3 comprises the candidate reference signal information; and the network equipment determines a second reference signal according to the candidate reference signal information and sends a message 4 to the terminal equipment, and the message 4 is associated with the second reference signal. Therefore, the appropriate reference signal can be selected for transmission, so that the uplink information and the downlink information can be transmitted by using the appropriate beam, and the transmission efficiency and performance can be improved.

Description

[0001] This application is a divisional application. The application number of the original application is 201980103202.X, and the original application date is December 31, 2019. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a random access method and a communication device. Background Art

[0003] Beamforming technology is used to limit the energy of the transmitted signal to a certain beam direction, thereby enhancing the signal strength and improving the signal reception efficiency. Beamforming technology can effectively expand the transmission range of wireless signals and reduce signal interference, thereby achieving higher communication efficiency and obtaining higher network capacity.

[0004] In a communication system using beamforming technology, for example, the communication system includes a network device and a terminal device, the network device uses beams to send and receive signals, and the terminal device also uses beams to send and receive signals. Different beams correspond to different reference signals. How to select a suitable reference signal for transmission is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide a random access method and a communication device, which can select a suitable reference signal for transmission, so that a suitable beam can be used for transmission, thereby improving the efficiency and performance of transmission.

[0006] A first aspect of an embodiment of the present application provides a random access method, including:

[0007] Sending a message 1 to a network device, where the message 1 is associated with a first reference signal;

[0008] receiving a message 2 from a network device, the message 2 being associated with a first reference signal;

[0009] Sending a message 3 to a network device, where the message 3 includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal; optionally, the message 3 is associated with the first reference signal;

[0010] receiving a message 4 from a network device, the message 4 being associated with a second reference signal;

[0011] The first reference signal and the second reference signal are synchronization signal blocks, belonging to the same synchronization signal block period. In addition to being synchronization signal blocks, the first reference signal and the second reference signal may also be channel state information reference signals.

[0012] The method provided in the first aspect of the embodiment of the present application can be executed by a terminal device, or by a component of the terminal device (such as a processor, a chip, or a chip system, etc.). The reference signal associated with messages 1 to 4 is not fixed to a certain reference signal, so that the uplink information and downlink information after message 4 can be associated with different reference signals, and the association with different reference signals is also associated with different beams, which can realize the use of appropriate beams to transmit signals, thereby improving the efficiency and performance of transmission.

[0013] In a possible implementation manner, after receiving the message 4 from the network device, one or more of the following is further included:

[0014] (1) sending uplink information to a network device, where the uplink information is associated with a first reference signal;

[0015] (2) receiving downlink information from a network device, where the downlink information is associated with a second reference signal;

[0016] (3) sending uplink information to the network device, where the uplink information is associated with the second reference signal;

[0017] (4) Receive downlink information from a network device, where the downlink information is associated with a first reference signal.

[0018] The terminal device may execute one of (1)-(4), or two or more of the four items. For example, by executing (1) and (2), the uplink information may be associated with the first reference signal, and the downlink information may be associated with the second reference signal, so that the uplink information may be associated with a suitable uplink beam or downlink beam, and the downlink information may be associated with a suitable downlink beam or uplink beam. For another example, by executing (1) and (3), the uplink information may be associated with the first reference signal at a certain moment, and with the second reference signal at another moment, so that the beam associated with the uplink information may be flexibly selected.

[0019] In one possible implementation, message 2 may be used to indicate a reference signal associated with message 3, and may indicate that the reference signal associated with message 3 is a first reference signal, so that when the terminal device sends message 3, it may use a beam corresponding to the first reference signal.

[0020] In a possible implementation, before sending message 1 to the network device, the terminal device may determine the first reference signal so that the terminal device can use the beam corresponding to the first reference signal to send message 1. The terminal device may determine the first reference signal from multiple reference signals based on the measurement results of each reference signal and / or the back-off power corresponding to each reference signal. The measurement results may include the reference signal received power and / or the signal-to-noise ratio of layer 1. The back-off power refers to the amount of reducing the transmit power.

[0021] In a possible implementation, before sending message 1 to the network device, the terminal device may further select a second reference signal so that the terminal device carries the index of the second reference signal in message 3. The terminal device may select the second reference signal from multiple reference signals according to the measurement results of each reference signal and / or the back-off power corresponding to each reference signal.

[0022] The random access timing for selecting the first reference signal may be different from the random access timing for selecting the second reference signal. For example, the first reference signal is selected at random access timing 1 and the second reference signal is selected at random access timing 2.

[0023] The method for selecting the first reference signal may be the same as or different from the method for selecting the second reference signal. For example, the first reference signal is selected from multiple reference signals based on the reference signal received power of each reference signal and the back-off power of each reference signal; and the second reference signal is selected from multiple reference signals based on the signal-to-noise ratio of layer 1 of each reference signal.

[0024] In a possible implementation, the candidate reference signal information included in message 3 may include one or more of the following: path loss information, an index of the second reference signal, a back-off power corresponding to the reference signal, and a measurement result of the reference signal. The path loss information, the back-off power corresponding to the reference signal, and the measurement result of the reference signal may be used by the network device to determine the second reference signal.

[0025] A second aspect of an embodiment of the present application provides a random access method, including:

[0026] receiving a message 1 from a terminal device, where the message 1 is associated with a first reference signal;

[0027] Sending a message 2 to a terminal device, where the message 2 is associated with a first reference signal;

[0028] receiving a message 3 from a terminal device, the message 3 including candidate reference signal information; optionally, the message 3 is associated with a first reference signal;

[0029] Determining a second reference signal according to the candidate reference signal information;

[0030] Sending a message 4 to a terminal device, where the message 4 is associated with a second reference signal;

[0031] The first reference signal and the second reference signal are synchronization signal blocks, belonging to the same synchronization signal block period. In addition to being synchronization signal blocks, the first reference signal and the second reference signal may also be channel state information reference signals.

[0032] The method provided in the second aspect of the embodiment of the present application can be executed by a network device, or by a component of the network device (such as a processor, a chip, or a chip system, etc.). The reference signal associated with messages 1 to 4 is not fixed to a certain reference signal, so that the uplink information and downlink information after message 4 can be associated with different reference signals, and the association with different reference signals is also associated with different beams, which can realize the use of appropriate beams to transmit signals, thereby improving the efficiency and performance of transmission.

[0033] The method provided in the second aspect corresponds to the method provided in the first aspect, and reference may be made to the description of various implementation methods of the first aspect.

[0034] In a possible implementation, if the candidate reference signal information includes path loss information, the network device may determine the second reference signal based on the path loss information. If the candidate reference signal information includes the index of the second reference signal, the network device may directly determine the second reference signal. If the candidate reference signal information includes the measurement results of each reference signal, the network device may determine the second reference signal from multiple reference signals based on the measurement results of each reference signal. If the candidate reference signal information includes the backoff power corresponding to each reference signal, the network device may determine the second reference signal from multiple reference signals based on the backoff power corresponding to each reference signal. If the candidate reference signal information includes the measurement results of each reference signal and the backoff power corresponding to each reference signal, the network device may determine the second reference signal from multiple reference signals based on the measurement results and the backoff power.

[0035] A third aspect of an embodiment of the present application provides a random access method, including:

[0036] Sending a message A to a network device, where the message A is associated with a first reference signal; the message A includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal;

[0037] receiving a message B from a network device, the message B being associated with a second reference signal;

[0038] The first reference signal and the second reference signal are synchronization signal blocks, belonging to the same synchronization signal block period. In addition to being synchronization signal blocks, the first reference signal and the second reference signal may also be channel state information reference signals.

[0039] The method provided in the third aspect of the embodiment of the present application can be executed by a terminal device, or by a component of the terminal device (such as a processor, a chip, or a chip system, etc.). The reference signal associated with message A and message B is not fixed to a certain reference signal, so that the uplink information and downlink information after message B can be associated with different reference signals, and the association with different reference signals is also associated with different beams, which can realize the use of appropriate beams to transmit signals, thereby improving the efficiency and performance of transmission.

[0040] In a possible implementation manner, after receiving the message B from the network device, one or more of the following is also included:

[0041] (1) sending uplink information to a network device, where the uplink information is associated with a first reference signal;

[0042] (2) receiving downlink information from a network device, where the downlink information is associated with a second reference signal;

[0043] (3) sending uplink information to the network device, where the uplink information is associated with the second reference signal;

[0044] (4) Receive downlink information from a network device, where the downlink information is associated with a first reference signal.

[0045] The terminal device may execute one of (1)-(4), or two or more of the four.

[0046] In a possible implementation, the candidate reference signal information included in message A may include one or more of the following: path loss information, an index of the second reference signal, a back-off power corresponding to the reference signal, and a measurement result of the reference signal. The path loss information, the back-off power corresponding to the reference signal, and the measurement result of the reference signal may be used by the network device to determine the second reference signal.

[0047] A fourth aspect of an embodiment of the present application provides a random access method, including:

[0048] receiving a message A from a terminal device, the message A being associated with a first reference signal; the message A including candidate reference signal information;

[0049] Determining a second reference signal according to the candidate reference signal information;

[0050] Sending a message B to the terminal device, where the message B is associated with the second reference signal;

[0051] The first reference signal and the second reference signal are synchronization signal blocks, belonging to the same synchronization signal block period. In addition to being synchronization signal blocks, the first reference signal and the second reference signal may also be channel state information reference signals.

[0052] The method provided in the fourth aspect of the embodiment of the present application can be executed by a network device, or by a component of the network device (such as a processor, a chip, or a chip system, etc.). The reference signal associated with message A and message B is not fixed to a certain reference signal, so that the uplink information and downlink information after message B can be associated with different reference signals, and the association with different reference signals is also associated with different beams, which can realize the use of appropriate beams to transmit signals, thereby improving the efficiency and performance of transmission.

[0053] The method provided in the fourth aspect corresponds to the method provided in the third aspect, and reference may be made to the description of various implementation methods of the third aspect.

[0054] A fifth aspect of the embodiments of the present application provides a communication device, which may be a terminal device, or a device in a terminal device, or a device that can be used in combination with a terminal device. The communication device has the function of implementing some or all of the functions of the terminal device in the method example described in the first aspect or the third aspect. For example, the functions of the terminal device may have the functions of some or all of the embodiments in the embodiments of the present application, or may have the functions of implementing any embodiment of the present application alone. The function may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0055] In a possible design, the structure of the terminal device may include a processing unit and a communication unit. The processing unit is configured to support the terminal device to perform the corresponding functions of the method provided in the first aspect or the third aspect. The communication unit is used to support communication between the terminal device and other devices, and the other devices may be network devices. The terminal device may also include a storage unit, which is coupled to the processing unit and the communication unit and stores the necessary programs / instructions and data of the terminal device.

[0056] In one implementation, the terminal device includes a processing unit and a communication unit;

[0057] A processing unit, configured to send a message 1 to a network device using a communication unit, wherein the message 1 is associated with a first reference signal; receive a message 2 from the network device, wherein the message 2 is associated with the first reference signal; send a message 3 to the network device, wherein the message 3 includes candidate reference signal information, wherein the candidate reference signal information is used to determine a second reference signal; receive a message 4 from the network device, wherein the message 4 is associated with the second reference signal;

[0058] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0059] In another embodiment, the terminal device includes a processing unit and a communication unit;

[0060] A processing unit is configured to send a message A to a network device using a communication unit, where the message A is associated with a first reference signal; the message A includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal; and receive a message B from the network device, where the message B is associated with the second reference signal;

[0061] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0062] As an example, the processing unit may be a processor, the communication unit may be a transceiver, and the storage unit may be a memory.

[0063] In one implementation, the terminal device includes a processor and a transceiver;

[0064] The processor is configured to send a message 1 to a network device using a transceiver, wherein the message 1 is associated with a first reference signal; receive a message 2 from the network device, wherein the message 2 is associated with the first reference signal; send a message 3 to the network device, wherein the message 3 includes candidate reference signal information, wherein the candidate reference signal information is used to determine a second reference signal; receive a message 4 from the network device, wherein the message 4 is associated with the second reference signal;

[0065] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0066] In another embodiment, the terminal device includes a processor and a transceiver;

[0067] The processor is configured to send a message A to a network device using a transceiver, the message A being associated with a first reference signal; the message A including candidate reference signal information, the candidate reference signal information being used to determine a second reference signal; and receive a message B from the network device, the message B being associated with the second reference signal;

[0068] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0069] In the specific implementation process, the processor can be used to perform the method provided in the first aspect or the third aspect above, such as but not limited to baseband related processing, and the transceiver can be used to perform, such as but not limited to, radio frequency transceiver. The above-mentioned devices can be respectively arranged on chips independent of each other, or at least partially or completely arranged on the same chip. For example, the processor can be further divided into an analog baseband processor and a digital baseband processor. Among them, the analog baseband processor can be integrated with the transceiver on the same chip, and the digital baseband processor can be arranged on an independent chip. With the continuous development of integrated circuit technology, more and more devices can be integrated on the same chip. For example, the digital baseband processor can be integrated with a variety of application processors (such as but not limited to graphics processors, multimedia processors, etc.) on the same chip. Such a chip can be called a system on chip or a chip system. Whether each device is independently arranged on different chips or integrated on one or more chips often depends on the specific needs of product design. The embodiment of the present application does not limit the specific implementation form of the above-mentioned devices.

[0070] The sixth aspect of the embodiment of the present application provides a processor for executing the method provided in any of the first aspect or the third aspect. In the process of executing the method provided in the first aspect or the third aspect, the process of sending the above information or data and receiving the above information or data can be understood as the process of outputting the above information or data by the processor, and the process of receiving the above information or data input by the processor. Specifically, when outputting the above information or data, the processor outputs the above information or data to the transceiver so that it can be transmitted by the transceiver. Further, after the above information or data is output by the processor, it may also be processed in other ways before it reaches the transceiver. Similarly, when the processor receives the above information or data input, the transceiver receives the above information or data and inputs it into the processor. Further, after the transceiver receives the above information or data, the above information or data may be processed in other ways before it is input into the processor.

[0071] Based on the above principles, for example, the receiving message mentioned in the method provided in the first aspect or the third aspect can be understood as the transceiver inputting the received message into the processor.

[0072] In this way, for the transmission, sending and receiving operations involved in the processor, unless otherwise specified, or unless otherwise contradictory to its actual function or internal logic in the relevant description, they can be more generally understood as processor output, reception, input and other operations, rather than the transmission, sending and receiving operations performed by the RF circuit and antenna.

[0073] In the specific implementation process, the above processor can be a processor specifically used to execute these methods, or a processor that calls computer instructions in the memory to execute these methods, such as a general-purpose processor. The above memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or can be set on different chips. The embodiment of the present application does not limit the type of memory and the setting method of the memory and the processor.

[0074] A seventh aspect of an embodiment of the present application provides a chip system, which includes a processor and an interface, and the chip system can be deployed in a terminal device.

[0075] In one possible design, the processor is configured to send a message 1 to a network device through an interface, the message 1 being associated with a first reference signal; receive a message 2 from the network device, the message 2 being associated with the first reference signal; send a message 3 to the network device, the message 3 including candidate reference signal information, the candidate reference signal information being used to determine a second reference signal; receive a message 4 from the network device, the message 4 being associated with the second reference signal;

[0076] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0077] In one possible design, a processor is configured to send a message A to a network device through an interface, the message A being associated with a first reference signal; the message A including candidate reference signal information, the candidate reference signal information being used to determine a second reference signal; and receive a message B from the network device, the message B being associated with the second reference signal;

[0078] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0079] An eighth aspect of an embodiment of the present application provides a computer-readable storage medium for storing computer programs / instructions used for the above-mentioned terminal device, which includes programs / instructions involved in executing the method described in the first aspect or the third aspect above.

[0080] A ninth aspect of the embodiments of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the first or third aspect above.

[0081] A tenth aspect of the embodiments of the present application provides a computer program comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the first aspect or the third aspect above.

[0082] The eleventh aspect of the embodiments of the present application provides a communication device, which may be a network device, or a device in a network device, or a device that can be used in combination with a network device. The communication device has some or all of the functions of the terminal device in the method example described in the second aspect or the fourth aspect. For example, the function of the network device may have some or all of the functions in the embodiments of the present application, or may have the function of implementing any of the embodiments of the present application separately. The function may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0083] In a possible design, the structure of the network device may include a processing unit and a communication unit. The processing unit is configured to support the terminal device to perform the corresponding functions of the method provided in the second aspect or the fourth aspect. The communication unit is used to support communication between the network device and other devices, and the other devices may be terminal devices. The network device may also include a storage unit, which is coupled to the processing unit and the communication unit and stores necessary program instructions and data for the network device.

[0084] In one embodiment, the network device includes a processing unit and a communication unit;

[0085] A processing unit, a processing unit, configured to receive a message 1 from a terminal device using the communication unit, the message 1 being associated with a first reference signal; send a message 2 to the terminal device, the message 2 being associated with the first reference signal; receive a message 3 from the terminal device, the message 3 including candidate reference signal information; determine a second reference signal according to the candidate reference signal information; send a message 4 to the terminal device, the message 4 being associated with the second reference signal;

[0086] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0087] In another embodiment, the network device includes a processing unit and a communication unit;

[0088] A processing unit, configured to receive a message A from a terminal device using a communication unit, the message A being associated with a first reference signal; the message A including candidate reference signal information; determining a second reference signal according to the candidate reference signal information; and sending a message B to the terminal device, the message B being associated with the second reference signal;

[0089] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0090] As an example, the processing unit may be a processor, the communication unit may be a transceiver, and the storage unit may be a memory.

[0091] In one implementation, the terminal device includes a processor and a transceiver;

[0092] The processor is configured to receive a message 1 from a terminal device using a transceiver, wherein the message 1 is associated with a first reference signal; send a message 2 to the terminal device, wherein the message 2 is associated with the first reference signal; receive a message 3 from the terminal device, wherein the message 3 includes candidate reference signal information; determine a second reference signal according to the candidate reference signal information; and send a message 4 to the terminal device, wherein the message 4 is associated with the second reference signal;

[0093] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0094] In another embodiment, the terminal device includes a processor and a transceiver;

[0095] The processor is configured to receive a message A from a terminal device using a transceiver, the message A being associated with a first reference signal; the message A including candidate reference signal information; determining a second reference signal according to the candidate reference signal information; and sending a message B to the terminal device, the message B being associated with the second reference signal;

[0096] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0097] In the specific implementation process, the processor can be used to perform the method provided in the second aspect or the fourth aspect, such as but not limited to baseband related processing, and the transceiver can be used to perform, such as but not limited to radio frequency transceiver. The above devices can be respectively arranged on independent chips, or at least partially or completely arranged on the same chip.

[0098] A twelfth aspect of an embodiment of the present application provides a processor for executing the method provided in the second or fourth aspect above.

[0099] A thirteenth aspect of an embodiment of the present application provides a chip system, which includes a processor and an interface, and the chip system can be deployed in a network device.

[0100] In one possible design, the processor is configured to receive a message 1 from a terminal device through an interface, the message 1 being associated with a first reference signal; send a message 2 to the terminal device, the message 2 being associated with the first reference signal; receive a message 3 from the terminal device, the message 3 including candidate reference signal information; determine a second reference signal according to the candidate reference signal information; send a message 4 to the terminal device, the message 4 being associated with the second reference signal;

[0101] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0102] In one possible design, the processor is configured to receive a message A from a terminal device through an interface, the message A being associated with a first reference signal; the message A including candidate reference signal information; determining a second reference signal according to the candidate reference signal information; and sending a message B to the terminal device, the message B being associated with the second reference signal;

[0103] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0104] A fourteenth aspect of an embodiment of the present application provides a computer-readable storage medium for storing computer programs / instructions used for the above-mentioned terminal device, which includes programs / instructions involved in executing the method described in the second aspect or the fourth aspect above.

[0105] A fifteenth aspect of the embodiments of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the second or fourth aspect above.

[0106] A sixteenth aspect of the embodiments of the present application provides a computer program comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the second or fourth aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0107] Figure 1a is a schematic diagram of a four-step contention-based random access process;

[0108] Figure 1b is a schematic diagram of a contention-based two-step random access process;

[0109] Figure 2 is an example diagram of a synchronization signal block period;

[0110] Figure 3 An example diagram of beam alignment is shown below;

[0111] Figure 4 A schematic diagram of a network architecture for applying an embodiment of the present application;

[0112] Figure 5 A schematic diagram of a random access method provided in an embodiment of the present application;

[0113] Figure 6 An example diagram of beam alignment provided in an embodiment of the present application;

[0114] Figure 7 Based on Figure 5 An example diagram of

[0115] Figure 8 A schematic diagram of a flow chart of another random access method provided in an embodiment of the present application;

[0116] Fig. 9 Based on Figure 8 An example diagram of

[0117] Fig.10 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0118] Fig.11 A schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0119] Fig.12 A schematic diagram of the structure of a chip provided in an embodiment of the present application;

[0120] Fig.13 A schematic diagram of the structure of a terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0121] In order to better understand the technical solutions provided by the embodiments of the present application, the technologies or names involved in the embodiments of the present application are first introduced.

[0122] 1. Random access process

[0123] The random access process refers to the process from when the terminal device sends a random access preamble sequence to try to access the network device to when it establishes a basic signaling connection with the network device. The terminal device establishes a connection with the cell and obtains uplink synchronization through the random access process. The random access process can be divided into a contention-based random access process and a non-contention-based random access process. In the contention-based random access process, the random access preamble sequence is generated by the terminal device. The random access preamble sequences generated by different terminal devices may conflict (that is, access is performed using the same random access preamble sequence). The network device needs to resolve the access of different terminal devices through competition. In the non-contention-based random access process, the random access preamble sequence is allocated by the network device to the terminal device, which can avoid conflicts in the random access preamble sequences of different terminal devices. The contention-based random access process can be divided into a contention-based four-step random access process and a contention-based two-step random access process.

[0124] (1) Contention-based four-step random access process

[0125] The four-step random access process based on contention can be found in Figure 1a Schematic diagram shown. Figure 1aIn the process, the terminal device sends a random access preamble sequence to the network device; the network device sends a random access response (RAR) to the terminal device; the terminal device sends message 3 (message 3, Msg3) to the network device; and the network device sends message 4 to the terminal device.

[0126] Among them, the random access preamble sequence can also be described as message 1 (message1, Msg1) or message 1 carrying a random access preamble sequence, etc.; the random access response can also be described as message 2 (message2, Msg2) or message 2 carrying a random access response, etc.; message 4 can also be described as a contention resolution message or a conflict resolution message, etc.

[0127] The terminal device sends the selected random access preamble sequence on the selected physical random access channel (PRACH) occasion. When sending, the random access radio network temporary identity (RA-RNTI) is calculated according to the selected PRACH occasion. One PRACH occasion corresponds to one RA-RNTI. When the terminal device subsequently receives message 2, it monitors the physical downlink control channel (PDCCH) scrambled by its own RA-RNTI, so as to determine that it is the PDCCH sent to itself. After sending the random access preamble sequence, the terminal device monitors the PDCCH within a window. The PDCCH will indicate the location of the physical downlink shared channel (PDSCH), and the PDSCH includes the RAR. Message 3 may include the terminal device's identity, which is used for contention resolution. For a terminal device in a connected state, the identity may be a cell radio network temporary identity (C-RNTI). Message 4 may include an identifier. If the identifier is consistent with the identifier included in message 3, the contention resolution is successful and the terminal device can access the network device. If the identifier is inconsistent with the identifier included in message 3, the contention resolution fails and the terminal device fails to access the network device.

[0128] (2) Contention-based two-step random access process

[0129] The contention-based two-step random access process can be found in Figure 1b Schematic diagram shown. Figure 1b In the example, the terminal device sends message A to the network device; the network device sends message B to the terminal device.

[0130] Message A may include a random access preamble sequence and a physical uplink shared channel (PUSCH). Message B is a response message after the network device receives message A, and may include a time advance (TA).

[0131] In the embodiment of the present application, the contention-based four-step random access process is described using messages 1 to 4; the contention-based two-step random access process is described using messages A and B.

[0132] 2. Synchronization signal / physical broadcast channel block (SS / PBCH block)

[0133] The synchronization signal / physical broadcast channel block may be referred to as a synchronization signal block (SSB). For the convenience of description, the synchronization signal block (SSB) is used for description in the embodiment of the present application. The synchronization signal block may include one or more of a physical broadcast channel (PBCH), a primary synchronization signal (PSS), and a secondary synchronization signal (SSS).

[0134] A synchronization signal block period (or SSB period) may include one or more SSBs, such as 4, 8, or 64 SSBs. th -generation, 5G) communication technology), multiple SSBs included in one SSB cycle do not have a quasi co-located (QCL) relationship. Having a QCL relationship means that one or more of the following can be used: the same delay spread, the same Doppler spread, the same average gain, the same average delay, the same spatial parameters for sending or receiving signals, and the same beam for sending or receiving signals.

[0135] The duration of the synchronization signal block included in the synchronization signal block period may be 5 milliseconds (ms). During the implementation process, the network device may send the SSB in a spatial beam scanning manner, and the terminal device scans multiple SSBs in the SSB period within 5ms. For example, if an SSB period includes 8 SSBs, the terminal device scans 8 SSBs within 5ms. The synchronization signal block period may be one of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms}.

[0136] For example, see Figure 2 An example diagram of the SSB cycle is shown. Figure 2 In the SSB cycle, there are 8 SSBs. When the network device sends SSBs in this SSB cycle, it can use 8 different beams to send these 8 SSBs respectively, and each SSB corresponds to a beam. The network device can use beams to send SSBs and can also use beams to receive signals; the terminal device can also use beams to send and receive signals.

[0137] When the beam of the network device is aligned with the beam of the terminal device, a matching beam pair will appear, and the performance of signal transmission through the matching beam pair is better than that of signal transmission without the matching beam pair. The terminal device can obtain the matching beam pair based on beam measurement. For example, see Figure 3 As shown in the example diagram, the terminal device can obtain a matching beam pair (including a downlink beam of the network device and beam 1 of the terminal device) based on beam measurement. The beam pair may also be referred to as a connection beam pair or a data connection beam pair (beam pair link, BPL), etc.

[0138] Figure 3 In the example, the user is close to point A of the terminal device. When the terminal device uses beam 1 for uplink data transmission, power backoff is required; point B of the terminal device is far away from the user. Although the performance of beam 2 is worse than that of beam 1, if beam 2 is used for uplink data transmission, power backoff is not required. However, the terminal device still selects beam 1 for uplink data transmission. Even if the difference corresponding to beam 1 is smaller than the difference corresponding to beam 2, beam 1 will be selected for uplink data transmission. The difference corresponding to beam 1 refers to the difference between the layer 1 reference signal receiving power (L1-RSRP) of the downlink beam corresponding to beam 1 and the maximum allowable radiation (MPE) corresponding to beam 1, that is, the difference between L1-RSRP1 and MPE1; the difference corresponding to beam 2 refers to the difference between the L1-RSRP of the uplink beam corresponding to beam 2 and the MPE corresponding to beam 2, that is, the difference between L1-RSRP2 and MPE2.

[0139] Among them, MPE is the maximum radiation allowed by the terminal equipment. In order to meet the MPE specifications of different countries and regions, it is necessary to reduce the transmit power to meet the MPE specifications. According to the time average value requirements in the standard, the time average integral dynamic control method can be used to adjust the transmit power in different ways to ensure that it does not exceed the standard within any standard time window. The above-mentioned power backoff refers to reducing the transmit power. For example, when the terminal device uses beam 1 for uplink data transmission, the transmit power needs to be reduced. The MPE corresponding to the beam can be understood as the amount by which the transmit power needs to be reduced, that is, how much the transmit power needs to be reduced.

[0140] Figure 3 In the present invention, for the terminal device, beam 1 is a downlink beam and beam 2 is an uplink beam. However, the current solution selects the downlink beam instead of the uplink beam when performing uplink data transmission. It is understandable that in the current solution, when a matching beam pair is determined, the matching beam pair is used for uplink and downlink transmission. However, the matching beam pair may not be suitable for uplink transmission or downlink transmission, so that the network device and the terminal device cannot use the appropriate beam for transmission.

[0141] In view of this, an embodiment of the present application provides a random access method and a communication device, which can select a suitable reference signal for transmission during and after the random access process, so that a suitable beam can be used for transmission, thereby improving the efficiency and performance of the transmission.

[0142] In the embodiment of the present application, a suitable uplink beam refers to an uplink beam determined by comprehensively considering factors such as power backoff and beam performance, and a suitable downlink beam is also a downlink beam determined by comprehensively considering factors such as power backoff and beam performance. Suitable can also be described as appropriate, better, more preferred, optional, etc. A suitable uplink beam can be called an uplink beam, and a suitable downlink beam can be called a downlink beam. In the following description, unless otherwise specified, an uplink beam can be interchanged with a suitable uplink beam, and a downlink beam can be interchanged with a suitable downlink beam.

[0143] The technical scheme in the embodiment of the present application will be described below in conjunction with the drawings in the embodiment of the present application. Among them, in the description of the embodiment of the present application, unless otherwise specified, " / " indicates that the objects associated before and after are an "or" relationship, for example, A / B can represent A or B; "and / or" represents three relationships, for example, a and / or b can represent a, b, a and b, these three relationships. In the description of the present application, unless otherwise specified, "multiple" refers to two or more than two. In addition, in order to facilitate the clear description of the technical scheme of the embodiment of the present application, in the embodiment of the present application, the words "first", "second" and the like are used to distinguish between technical features with basically the same or similar functions and effects. Those skilled in the art can understand that the words "first", "second" and the like do not limit the quantity and execution order, and the words "first", "second" and the like do not limit them to be necessarily different.

[0144] See also Figure 4 , is a schematic diagram of a network architecture for applying an embodiment of the present application. Figure 4 The network architecture shown includes a network device 401 and a terminal device 402 . Figure 4 The device form and quantity shown are for illustrative purposes only and do not constitute a limitation on the embodiments of the present application. For example, a network device can communicate with multiple terminal devices, and a terminal device can be connected to multiple network devices.

[0145] Among them, the network device 401 can be any device with wireless transceiver function. Including but not limited to: a base station in a Long Term Evolution (LTE) system or a base station (next-generation Node basestation, gNodeB or gNB) in a NR system or a transmission receiving point (transmission receiving point / transmission reception point, TRP) in a NR system, a base station of subsequent evolution of 3GPP, an access node in a WiFi system, a wireless relay node, a wireless backhaul node, etc. The base station can be: a macro base station, a micro base station, a micro-micro base station, a small station, a relay station, or a balloon station, etc. Multiple base stations can support the networks of the same technology mentioned above, or they can support the networks of different technologies mentioned above. The network device 401 can also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The network device 401 can also be a server, a wearable device, or a vehicle-mounted device, etc. The following is an example of network device 401 being a base station. The multiple network devices may be base stations of the same type or different types. A base station may communicate with a terminal device or communicate with the terminal device through a relay station.

[0146] Among them, the terminal device 402 is a device with wireless transceiver function, which can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.). The terminal device 402 can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a vehicle-mounted terminal device, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a wearable terminal device, etc. The embodiments of the present application do not limit the application scenarios. The terminal device 402 may also be sometimes referred to as a terminal, a mobile terminal, a user equipment (UE), an access terminal device, a vehicle-mounted terminal, an industrial control terminal, a UE unit, a UE station, a mobile station, a mobile station, a remote station, a remote terminal device, a mobile device, a UE agent or a UE device, etc. The terminal device 402 may also be fixed or mobile.

[0147] In the embodiment of the present application, the network device 401 is a network device that supports multiple beams, for example, it can support beams based on wide coverage, and it can also support beams based on fixed wireless access (FWA) precise coverage, and so on.

[0148] In the embodiment of the present application, the network device 401 and the terminal device 402 can perform a contention-based four-step random access process or a contention-based two-step random access process. With the embodiment of the present application, during and after the random access process, a suitable reference signal is selected for transmission, so that the network device 401 and the terminal device 402 can use a suitable beam for transmission, thereby improving the efficiency and performance of the transmission.

[0149] The embodiments of the present application can be applied to LTE systems, NR systems, and can also be applied to future communication systems, such as future networks or sixth-generation communication systems.

[0150] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that with the evolution of the network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0151] based on Figure 4 The network architecture shown in the figure, the random access method provided by the embodiment of the present application will be described in detail below. In the introduction process, the names of the messages or signals exchanged between the terminal device and the network device are used as examples and do not constitute a limitation on the embodiment of the present application.

[0152] See also Figure 5 , is a flow chart of a random access method provided in an embodiment of the present application, which is a four-step random access process based on contention. The process may include but is not limited to the following steps:

[0153] Step 501: The terminal device sends a message 1 to the network device, where the message 1 is associated with a first reference signal. Correspondingly, the network device receives the message 1 from the terminal device.

[0154] Step 502: The network device sends a message 2 to the terminal device, where the message 2 is associated with the first reference signal. Correspondingly, the terminal device receives the message 2 from the network device.

[0155] Step 503: The terminal device sends a message 3 to the network device, where the message 3 includes candidate reference signal information. Accordingly, the network device receives the message 3 from the terminal device. Optionally, the message 3 is associated with the first reference signal.

[0156] Step 504: The network device determines a second reference signal according to the candidate reference signal information.

[0157] Step 505: The network device sends a message 4 to the terminal device, where the message 4 is associated with the second reference signal. Correspondingly, the terminal device receives the message 4 from the network device.

[0158] In one possible implementation, the first reference signal and the second reference signal may be synchronization signal blocks (ie, SSBs) and belong to the same synchronization signal block period. That is, the first reference signal and the second reference signal may be different SSBs in the same SSB period, corresponding to different SSB indexes, having different beam directions, and having no QCL relationship. For example, the SSB period includes 8 SSBs (SSB0 to SSB7), the first reference signal is SSB1, and the second reference signal is SSB4, with different beam directions. The first reference signal and the second reference signal are different SSBs in the same SSB period, compared to different SSBs in different SSB periods (for example, the first reference signal is SSB1 in SSB period 1, and the second reference signal is SSB4 in SSB period 2), which can avoid searching for SSBs and beam measurements again, thereby saving latency.

[0159] In a possible implementation, the first reference signal and the second reference signal are channel state information reference signals (CSI-RS). The beam directions corresponding to the first CSI-RS and the second CSI-RS are different. The CSI-RS may be periodically configured, non-periodically configured, or semi-persistently configured. Whether the first CSI-RS and the second CSI-RS belong to the same CSI-RS period is related to the configuration of the CSI-RS. For example, if the CSI-RS is periodically configured, then the first CSI-RS and the second CSI-RS may belong to the same CSI-RS period. The first CSI-RS and the second CSI-RS may be CSI-RSs configured with different CSI-RS resources, that is, the CSI-RS resource configurations of the first CSI-RS and the second CSI-RS are different. The first CSI-RS and the second CSI-RS may be CSI-RSs configured with different CSI-RS resource sets, that is, the CSI-RS resource set configurations of the first CSI-RS and the second CSI-RS are different.

[0160] In addition to the above two methods, the first reference signal and the second reference signal may also be other types of reference signals, and other types of reference signals may satisfy that the first reference signal and the second reference signal have different beam directions and do not have a QCL relationship. In the embodiment of the present application, the first reference signal and the second reference signal are introduced as SSB as an example, that is, the first reference signal is the first SSB and the second reference signal is the second SSB as an example, and other types of reference signals may refer to SSB.

[0161] Before the terminal device executes step 501, the terminal device matches the SSB sent by the network device with its own beam to determine a matching beam pair. For example, see Figure 6The example diagram of beam alignment shown below assumes that the beam of SSB1 of the network device and the beam 1 of the terminal device are a matching beam pair. However, in the matching beam pair, the beam of SSB1 is not necessarily the uplink beam, that is, for uplink transmission, the beam of SSB1 is not necessarily suitable; or the beam of SSB1 is not necessarily the downlink beam, that is, for downlink transmission, the beam of SSB1 is not necessarily suitable. Therefore, the terminal device needs to determine the uplink beam and / or downlink beam. The uplink beam is used to achieve uplink transmission, and the downlink beam is used to achieve downlink transmission. The beam associated with the SSB refers to the beam corresponding to the SSB. One SSB corresponds to one beam, which can be understood as one SSB using one beam or one beam carrying one SSB, etc.

[0162] The terminal device can determine the uplink beam and / or downlink beam according to the measurement result of the SSB and / or the back-off power corresponding to the SSB.

[0163] In one embodiment, the terminal device can determine the uplink beam according to the measurement result of the SSB and the back-off power corresponding to the SSB. Among them, the measurement result of the SSB can include the reference signal receiving power (RSRP).

[0164] Assume that the beam of SSB1 and the beam 1 of the terminal device are a matching beam pair. The expected power configured by the network device is P0, the back-off power of the beam 1 of the terminal device is MPE1, and the RSRP of receiving SSB1 is PL1; the back-off power of the beam 2 of the terminal device is MPE2, and the RSRP of receiving SSB2 is PL2.

[0165] If |P0 + PL2 - MPE2| - |P0 + PL1 - MPE1| < X decibels (dB), the terminal device can select the beam of SSB1 as the uplink beam, and the transmit power is backed off by MPE1 (that is, the back-off power corresponding to SSB1 is MPE1); if |P0 + PL2 - MPE2| - |P0 + PL1 - MPE1| >= X dB, the terminal device can select the beam of SSB2 as the uplink beam, and the transmit power is backed off by MPE2 (that is, the back-off power corresponding to SSB2 is MPE2). Due to the power back-off factor, the maximum transmit powers of different beams of the terminal device are different: Pmax1 is used to represent the maximum transmit power of the beam 1 of the terminal device, and Pmax2 is used to represent the maximum transmit power of the beam 2 of the terminal device. When P0 + PL1 + Delta * n < Pmax1, the terminal device can select to use beam 1 for uplink transmission; otherwise, it can select to use beam 2 for uplink transmission.

[0166] As can be seen from the above, if |P0 + PL2 - MPE2| - |P0 + PL1 - MPE1| < X dB and P0 + PL1 + Delta * n < Pmax1, the terminal device can choose to use the beam of beam 1 and SSB1 to send uplink information; if |P0 + PL2 - MPE2| - |P0 + PL1 - MPE1| >= X dB and P0 + PL1 + Delta * n >= Pmax1 (or P0 + PL1 + Delta * n < Pmax2), the terminal device can choose to use the beam of beam 2 and SSB2 to send uplink information.

[0167] Among them, the specific value of X can be agreed upon by the protocol or configured by the network device. Delta represents the power adjustment amount. When the terminal device sends a random access preamble to the network device for the (n - 1)-th time and does not receive a random access response for this random access preamble, the terminal device adjusts the transmit power and, according to the adjusted power, sends a random access preamble to the network device for the n-th time. Delta represents the power adjustment amount between the transmit power of the random access preamble sent for the n-th time and the transmit power of the random access preamble sent for the (n - 1)-th time. n represents the n-th time, and n is an integer greater than or equal to 1.

[0168] The terminal device can also determine the downlink beam according to the measurement result of the SSB and the fallback power corresponding to the SSB. The specific process can refer to the process of determining the uplink beam.

[0169] It can be understood that when the terminal device selects an uplink beam, it is to select the SSB associated with the uplink information. For example, if the uplink beam is the beam of SSB1, then the uplink information can be associated with SSB1. When the terminal device selects a downlink beam, it is to select the SSB associated with the downlink information. For example, if the downlink beam is the beam of SSB2, then the downlink information can be associated with SSB2.

[0170] Among them, the uplink information is associated with SSB1, which can also be described as the uplink information is related to SSB1, the uplink information has an association relationship with SSB1, the SSB associated with the uplink information is SSB1, the beam used to send the uplink information corresponds to SSB1, or the beam used to send the uplink information is the beam of SSB1, etc. Association can also be described as mapping, correspondence, correlation, or assignment, etc. The uplink information is associated with SSB1, which can be understood as the uplink information has a QCL relationship with SSB1, and signals can be sent or received using the same delay spread, or the same Doppler spread, or the same average gain, or the same average delay, or the same spatial domain parameters, or the same beam for sending or receiving. The explanation of the downlink information associated with SSB2 can refer to the explanation of the uplink information associated with SSB1.

[0171] In one embodiment, the terminal device may determine the uplink beam according to the RSRP of the SSB and the backoff power corresponding to the SSB; determine the downlink beam according to the layer 1 signal to interference and noise ratio (L1-SINR) of the SSB. Or, determine the downlink beam according to the RSRP of the SSB and the backoff power corresponding to the SSB; determine the uplink beam according to the L1-SINR of the SSB. The L1-SINR of the SSB can be understood as one of the measurement results of the SSB. The embodiments of the present application do not limit how the terminal device determines the downlink beam or the uplink beam according to the L1-SINR of the SSB.

[0172] Exemplarily, the SSB cycle includes SSB0 to SSB7. According to the RSRP and fallback power of the SSB, the SSB associated with the uplink information is determined to be SSB0. Among SSB1 to SSB7, the L1-SINR of SSB4 is the largest, so it can be determined that the SSB associated with the downlink information is SSB4.

[0173] Among them, L1-SINR refers to the signal-to-noise ratio of the reference signal of the physical layer.

[0174] Optionally, taking the determination of the SSB associated with the downlink information according to the L1-SINR of the SSB as an example, the SSB associated with the downlink information is selected from the SSBs whose RSRP meets the threshold according to the L1-SINR of the SSB. For example, the SSBs whose RSRP meets the threshold include SSB3 to SSB7, and among these five SSBs, the L1-SINR of SSB4 is the largest, so the SSB associated with the downlink information can be selected as SSB4.

[0175] In one embodiment, the terminal device may determine the uplink beam and the downlink beam according to the L1-SINR of the SSB, that is, determine the SSB associated with the uplink information and the SSB associated with the downlink information.

[0176] In the above three embodiments, the terminal device selects a PRACH occasion of an SSB associated with uplink information, which is different from the PRACH occasion of an SSB associated with downlink information. For example, an SSB associated with uplink information is selected in PRACH occasion 1, and an SSB associated with downlink information is selected in PRACH occasion 2. The PRACH occasion may also be referred to as a random access channel (PACH) occasion or a random access occasion.

[0177] For step 502, message 1 is associated with the first SSB, which can be described as that the beam used by the terminal device to send message 1 is the same as the beam associated with the first SSB, or the terminal device uses the beam associated with the first SSB to send message 1, or the beam used by the terminal device to send message 1 is the beam associated with the first SSB, or the beam for sending message 1 has a QCL relationship with the beam associated with the first SSB, etc.

[0178] The protocol may stipulate that message 1 is associated with the first SSB, or the network device may configure message 1 to be associated with the first SSB. Further, the protocol may stipulate that the beam associated with message 1 and the first SSB is an uplink beam or a downlink beam, or the network device may configure the beam associated with message 1 and the first SSB to be an uplink beam or a downlink beam. That the beam associated with message 1 and the first SSB is an uplink beam can be understood as that the beam used by the terminal device to send message 1 is an uplink beam; that the beam associated with message 1 and the first SSB is a downlink beam can be understood as that the beam used by the terminal device to send message 1 is a downlink beam.

[0179] For step 502, the explanation of message 2 being associated with the first SSB can refer to the explanation of message 1 being associated with the first SSB. It can be understood that the beam used by the network device to send message 2 is the beam for receiving 1. The protocol may stipulate that message 2 is associated with the first SSB. Further, the protocol may stipulate that the beam associated with message 2 and the first SSB is an uplink beam or a downlink beam, or the network device may configure the beam associated with message 2 and the first SSB to be an uplink beam or a downlink beam according to the protocol. Optionally, if the beam associated with message 1 and the first SSB is an uplink beam, then the beam associated with message 2 and the first SSB is also an uplink beam; if the beam associated with message 1 and the first SSB is a downlink beam, then the beam associated with message 2 and the first SSB is also a downlink beam.

[0180] Optionally, message 2 may include first indication information, and the first indication information is used to indicate that the quality of the SSB corresponding to the uplink beam is Y dB lower than the quality of the SSB corresponding to the downlink beam, where Y < X. Then, when the terminal device obtains this indication information, it can use a contention-based two-step random access procedure for random access, thereby overcoming the problem of poor performance of message 2.

[0181] Optionally, message 2 may include second indication information, and the second indication information is used to indicate the SSB associated with message 3. For example, it indicates that the SSB associated with message 3 is the first SSB, that is, the SSB associated with message 3 is the same as the SSB associated with message 1. That is, the SSBs associated with the uplink messages in the random access procedure are the same, and the associated beams are the same.

[0182] For step 503, message 3 is associated with the first SSB, and its interpretation can refer to the interpretation of message 1 associated with the first SSB. Message 3 includes candidate reference signal information, and the candidate reference signal information is used by the network device to determine the second SSB. It can be understood that message 3 is used to report candidate beams, and the candidate beams can be uplink beams or downlink beams. The candidate beam is the beam associated with the second SSB. The protocol may specify that the candidate beam is an uplink beam or a downlink beam, or the network device may configure the candidate beam reported by message 3 to be an uplink beam or a downlink beam. If the beam associated with message 1 is an uplink beam, then the candidate beam is a downlink beam; if the beam associated with message 1 is a downlink beam, then the candidate beam is an uplink beam.

[0183] Among them, the candidate reference signal information may include one or more of the following: path loss information, the index of the second SSB, the backoff power corresponding to the SSB, and the measurement result of the SSB.

[0184] The path loss information specifies the path loss difference between the SSB corresponding to the uplink beam and the SSB corresponding to the downlink beam, for example, the path loss difference between the first SSB and the second SSB. The network device can determine the first SSB through message 1, and can determine the second SSB based on the path loss difference and the first SSB.

[0185] The index of the second SSB, that is, the terminal device can directly report the index of the second SSB, and the network device can directly determine the second SSB according to the index of the second SSB.

[0186] The fallback power corresponding to the SSB includes the index of each SSB and the fallback power corresponding to the index of each SSB. For example, it includes fallback power MPE0 corresponding to SSB0, fallback power MPE1 corresponding to SSB1, fallback power MPE2 corresponding to SSB2, and fallback power MPE3 corresponding to SSB3. The network device can determine the second SSB from multiple SSBs according to the fallback power corresponding to each SSB.

[0187] The measurement results of the SSB may include the index of each SSB and the measurement results corresponding to the index of each SSB. The measurement results may include RSRP and / or LI-SINR. The network device may determine the second SSB from multiple SSBs based on the measurement results of each SSB.

[0188] Optionally, the network device may determine the second SSB from multiple SSBs based on the backoff power corresponding to the SSB and the measurement result of the SSB.

[0189] For step 505, message 4 is associated with the second SSB, and its explanation can refer to the explanation of message 1 being associated with the first SSB.

[0190] In a possible implementation, when receiving message 4, the terminal device calculates the difference DeltaTA between the first time when message 4 is received and the second time when message 4 is estimated to be received, and adjusts the TA value of the uplink information sent according to the difference, and the adjustment amount is TA+DeltaTA. If the terminal device fails to receive message 4, for example, message 4 is not received due to timeout, the terminal device can use the beam associated with the first SSB to send a retransmission request message to the network device, and the retransmission request message is used to request the network device to retransmit message 4.

[0191] For example, see Figure 7 , based on Figure 5 An example diagram of . Figure 7 It is assumed that the first SSB is SSB2, and the beam associated with SSB2 is the uplink beam; the second SSB is SSB1, and the beam associated with SSB1 is the downlink beam. The terminal device selects SSB1 at random access channel occasion (RO) 1 and selects SSB2 at RO2. Message 1 is associated with SSB2, message 2 is associated with SSB2, message 3 is associated with SSB2, message 3 includes the index of SSB1, and message 4 is associated with SSB1. For another example, the beam associated with SSB2 is the downlink beam, and the beam associated with SSB1 is the uplink beam.

[0192] In one possible implementation, if the network device fails to send message 4 using the beam associated with the first SSB, the beam associated with the second SSB may be used to send message 4, that is, message 4 is associated with the second SSB at this time. When receiving message 4, the terminal device calculates the difference DeltaTA between the first time when message 4 is received and the second time when message 4 is estimated to be received, and adjusts the TA value of the uplink information sent according to the difference, and the adjustment amount is TA+DeltaTA. It can be understood that in this method, when the network device fails to send message 4 using the beam associated with the first SSB, it uses the beam associated with the second SSB to send message 4 instead.

[0193] exist Figure 5 In the illustrated embodiment, during the four-step random access process, the SSB associated with the uplink message is different from the SSB associated with the downlink message, so that the transmission of the uplink message can use a suitable beam and the transmission of the downlink message can use a suitable beam, thereby improving transmission efficiency and performance.

[0194] As an optional embodiment, after step 505, one or more of the following is also included:

[0195] (1) The terminal device sends uplink information to the network device, where the uplink information is associated with the first SSB.

[0196] (2) The network device sends downlink information to the terminal device, where the downlink information is associated with the second SSB.

[0197] (3) The terminal device sends uplink information to the network device, where the uplink information is associated with the second SSB.

[0198] (4) The network device sends downlink information to the terminal device, where the downlink information is associated with the first SSB.

[0199] One, two or more of the above (1) to (4) may be executed.

[0200] In one possible implementation, (1) and (3) are performed. After the terminal device accesses the network device through a random access process, the uplink information sent to the network device can be associated with the first SSB at one moment and with the second SSB at another moment. That is, the uplink information is not fixedly associated with the first SSB.

[0201] In one possible implementation, (2) and (4) are executed. After the terminal device accesses the network device through a random access process, the downlink information sent by the network device to the terminal device may be associated with the first SSB at one moment and may be associated with the second SSB at another moment. That is, the downlink information is not fixedly associated with the second SSB.

[0202] In one possible implementation, (1) and (2) are performed, and after the terminal device accesses the network device through a random access process, the uplink information sent to the network device is associated with the first SSB; thereafter, the downlink information sent by the network device to the terminal device is associated with the second SSB.

[0203] In one possible implementation, (3) and (4) are performed, and after the terminal device accesses the network device through a random access process, the uplink information sent to the network device is associated with the second SSB; thereafter, the downlink information sent by the network device to the terminal device is associated with the first SSB.

[0204] The uplink information may be, for example, HARQ information of message 4, or message 5, or uplink data, or uplink signal, etc. The downlink information may be, for example, message 6, or downlink data, or downlink signal, etc.

[0205] In this optional embodiment, after the random access process, the uplink information and the downlink information are not fixedly associated with one SSB, which is flexible and has a wide adaptability, so that the uplink and downlink transmissions after the random access process have higher efficiency and performance.

[0206] See also Figure 8, is a flow chart of another random access method provided in an embodiment of the present application, which is a two-step random access process based on contention. The process may include but is not limited to the following steps:

[0207] Step 801: The terminal device sends a message A to the network device, the message A is associated with a first reference signal, and the message A includes candidate reference signal information. Correspondingly, the network device receives the message A from the terminal device.

[0208] Step 802: The network device determines a second reference signal according to candidate reference signal information.

[0209] Step 803: The network device sends a message B to the terminal device, where the message B is associated with the second reference signal. Correspondingly, the terminal device receives the message B from the network device.

[0210] The description of the first reference signal and the second reference signal can be found in Figure 5 The description of the first reference signal and the second reference signal in the illustrated embodiment will not be repeated here.

[0211] The description of the terminal device before executing step 801 is the same as Figure 5 The description of the terminal device before executing step 501 in the illustrated embodiment is similar. The difference is that: Figure 5 In the PRAChoccasion, the terminal device selects the SSB associated with the uplink information, which is different from the PRACH occasion that selects the SSB associated with the downlink information. Therefore, the terminal device carries the candidate reference signal information in message 3; Figure 8 In the message A, the PRACH occasion of the SSB associated with the uplink information selected by the terminal device may be the same as the PRACH occasion of the SSB associated with the downlink information selected, so the terminal device may carry the candidate reference signal information in message A.

[0212] For step 801, the explanation of the association of message A with the first SSB can refer to the explanation of the association of message 1 with the first SSB. Message A includes candidate reference signal information, which can be found in Figure 5 The description of the candidate reference signal information in the illustrated embodiment is not repeated here. Message A may include a random access preamble sequence and a PUSCH, and the PUSCH may include the candidate reference signal information. Message A is associated with the first SSB, which may be a random access preamble sequence associated with the first SSB.

[0213] For step 803, message B is associated with the second SSB, similar to the association of message 4 with the second SSB.

[0214] When receiving message B, the terminal device calculates the difference DeltaTA between the first time when message B is received and the estimated second time when message B is received, and adjusts the TA value of the uplink information sent according to the difference, and the adjustment amount is TA+DeltaTA.

[0215] For example, see Fig. 9 , based on Figure 8 An example diagram of . Fig. 9 It is assumed that the first SSB is SSB1, and the beam associated with SSB1 is the uplink beam; the second SSB is SSB2, and the beam associated with SSB2 is the downlink beam. The terminal device selects SSB1 and SSB2 in RO1. Message A is associated with SSB1, and message B is associated with SSB2. For another example, the beam associated with SSB1 is the downlink beam, and the beam associated with SSB2 is the uplink beam.

[0216] exist Figure 8 In the illustrated embodiment, during the two-step random access process, the SSB associated with the uplink message is different from the SSB associated with the downlink message, so that the transmission of the uplink message can use a suitable beam and the transmission of the downlink message can use a suitable beam, thereby improving transmission efficiency and performance.

[0217] As an optional embodiment, after step 803, one or more of the following is also included:

[0218] (1) The terminal device sends uplink information to the network device, where the uplink information is associated with the first SSB.

[0219] (2) The network device sends downlink information to the terminal device, where the downlink information is associated with the second SSB.

[0220] (3) The terminal device sends uplink information to the network device, where the uplink information is associated with the second SSB.

[0221] (4) The network device sends downlink information to the terminal device, where the downlink information is associated with the first SSB.

[0222] For this optional embodiment, reference may be made to the description after step 505, which will not be repeated here.

[0223] Corresponding to the method provided in the above method embodiment, the embodiment of the present application further provides a corresponding communication device, which includes a module for executing the corresponding module of the above embodiment. The module can be software, hardware, or a combination of software and hardware.

[0224] See also Fig.10 , is a structural diagram of a communication device provided in an embodiment of the present application. Fig.10The communication device 900 shown may include a communication unit 901 and a processing unit 902. The communication unit 901 may include a sending unit 9011 and a receiving unit 9012. The sending unit 9011 is used to implement a sending function, and the receiving unit 9012 is used to implement a receiving function. The communication unit 901 may implement a sending function and / or a receiving function. The communication unit 901 may also be described as a transceiver unit.

[0225] The communication device 900 may be a terminal device, or a device in a terminal device, or a device that can be used in conjunction with a terminal device.

[0226] The communication device 900 is used to implement Figure 5 Functions of the terminal device in the embodiment shown:

[0227] In one embodiment, the processing unit 902 is configured to use the communication unit 901 to send a message 1 to the network device, where the message 1 is associated with the first reference signal; receive a message 2 from the network device, where the message 2 is associated with the first reference signal; send a message 3 to the network device, where the message 3 includes candidate reference signal information, where the candidate reference signal information is used to determine the second reference signal; receive a message 4 from the network device, where the message 4 is associated with the second reference signal;

[0228] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0229] The processing unit 902 is further configured to determine a first reference signal from the multiple reference signals according to the measurement result of the reference signal and / or the back-off power corresponding to the reference signal.

[0230] In one embodiment, a sending unit 9011 is used to send a message 1 to a network device, and the message 1 is associated with a first reference signal; a receiving unit 9012 is used to receive a message 2 from the network device, and the message 2 is associated with the first reference signal; the sending unit 9011 is also used to send a message 3 to the network device, and the message 3 includes candidate reference signal information, and the candidate reference signal information is used to determine a second reference signal; the receiving unit 9012 is also used to receive a message 4 from the network device, and the message 4 is associated with the second reference signal; wherein the first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0231] The processing unit 902 is configured to determine a first reference signal from multiple reference signals according to a measurement result of the reference signal and / or a back-off power corresponding to the reference signal.

[0232] The communication device 900 is used to implement Figure 8 Functions of the terminal device in the embodiment shown:

[0233] In one embodiment, the processing unit 902 is configured to use the communication unit 901 to send a message A to the network device, where the message A is associated with the first reference signal; the message A includes candidate reference signal information, where the candidate reference signal information is used to determine the second reference signal; and receive a message B from the network device, where the message B is associated with the second reference signal;

[0234] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0235] In one embodiment, a sending unit 9011 is used to send a message A to a network device, where the message A is associated with a first reference signal; the message A includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal; a receiving unit 9012 is used to receive a message B from the network device, where the message B is associated with the second reference signal; wherein the first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0236] The communication device 900 may be a network device, or a device in a network device, or a device that can be used in conjunction with a network device.

[0237] The communication device 900 is used to implement Figure 5 The functions of the network devices in the illustrated embodiment are as follows:

[0238] In one embodiment, the processing unit 902 is configured to receive a message 1 from a terminal device using the communication unit 901, where the message 1 is associated with a first reference signal; send a message 2 to the terminal device, where the message 2 is associated with the first reference signal; receive a message 3 from the terminal device, where the message 3 includes candidate reference signal information; determine a second reference signal according to the candidate reference signal information; send a message 4 to the terminal device, where the message 4 is associated with the second reference signal;

[0239] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0240] In one embodiment, the receiving unit 9012 is used to receive a message 1 from a terminal device, and the message 1 is associated with a first reference signal; the sending unit 9011 is used to send a message 2 to the terminal device, and the message 2 is associated with the first reference signal; the receiving unit 9012 is also used to receive a message 3 from the terminal device, and the message 3 includes candidate reference signal information; the processing unit 902 is used to determine a second reference signal based on the candidate reference signal information; the sending unit 9011 is also used to send a message 4 to the terminal device; wherein the first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0241] The communication device 900 is used to implement Figure 8 The functions of the network devices in the illustrated embodiment are as follows:

[0242] In one embodiment, the processing unit 902 is configured to receive a message A from a terminal device using the communication unit 901, where the message A is associated with a first reference signal; the message A includes candidate reference signal information; determine a second reference signal according to the candidate reference signal information; and send a message B to the terminal device, where the message B is associated with the second reference signal;

[0243] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0244] In one embodiment, the receiving unit 9012 is used to receive a message A from a terminal device, where the message A is associated with a first reference signal; the message A includes candidate reference signal information; the sending unit 9011 is used to send a message B to the terminal device, where the message B is associated with a second reference signal; wherein the first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0245] Fig.11 A schematic diagram of the structure of a communication device is given. The communication device 1000 may be a terminal device, or a chip, a chip system, or a processor that supports the terminal device to implement the above method. The device may be used to implement the method described in the above method embodiment, and the details may refer to the description in the above method embodiment.

[0246] The communication device 1000 may include one or more processors 1001. The processor 1001 may be a general-purpose processor or a dedicated processor, etc. For example, it may be a baseband processor or a central processing unit. The baseband processor may be used to process the communication protocol and communication data, and the central processing unit may be used to control the communication device (such as a base station, a baseband chip, a terminal, a terminal chip, a DU or a CU, etc.), execute a software program, and process the data of the software program.

[0247] Optionally, the communication device 1000 may include one or more memories 1002, on which instructions 1004 may be stored, and the instructions may be executed on the processor 1001, so that the device 1000 performs the method described in the above method embodiment. Optionally, data may also be stored in the memory 1002. The processor 1001 and the memory 1002 may be provided separately or integrated together.

[0248] Optionally, the communication device 1000 may further include a transceiver 1005 and an antenna 1006. The transceiver 1005 may be referred to as a transceiver unit, a transceiver, a communication interface or a transceiver circuit, etc., for implementing a transceiver function. The transceiver 1005 may include a receiver and / or a transmitter, the receiver may be referred to as a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., for implementing a transmitting function.

[0249] The communication device 1000 is a terminal device: the processor 1001 can use the transceiver 1005 to execute Figure 5 Steps 501 to 503 and 505 in the above; Execute Figure 8 Step 801 and step 803 in .

[0250] In another optional design, the processor 1001 may include a transceiver for implementing the receiving and sending functions. For example, the transceiver may be a communication interface, a transceiver circuit, or an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and sending functions may be separate or integrated. The above-mentioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the above-mentioned transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0251] In another possible design, optionally, the processor 1001 may store an instruction 1003, and the instruction 1003 runs on the processor 1001, so that the device 1000 can execute the method described in the above method embodiment. The instruction 1003 may be solidified in the processor 1001, in which case the processor 1001 may be implemented by hardware.

[0252] In another possible design, the communication device 1000 may include a circuit that can implement the functions of sending or receiving or communicating in the aforementioned method embodiment. The processor and transceiver described in this application can be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit RFIC, a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channelmetal oxide semiconductor, PMOS), bipolar junction transistor (Bipolar Junction Transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0253] The communication device described in the above embodiments may be a network device or a terminal device, but the scope of the communication device described in the present application is not limited thereto, and the structure of the communication device may not be limited thereto. Fig.11 The communication device may be a stand-alone device or may be part of a larger device.

[0254] For the case where the communication device may be a chip or a chip system, see Fig.12 Schematic diagram of the chip structure shown. Fig.12 The chip 1100 shown includes a processor 1101 and an interface 1102. The number of the processor 1101 can be one or more, and the number of the interface 1102 can be multiple.

[0255] For the case where the chip is used to implement the functions of the terminal device in the embodiment of the present application:

[0256] In one design, processor 1101 sends message 1 to a network device through interface 1102, where message 1 is associated with a first reference signal; receives message 2 from the network device, where message 2 is associated with the first reference signal; sends message 3 to the network device, where message 3 includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal; receives message 4 from the network device, where message 4 is associated with the second reference signal;

[0257] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0258] In one design, processor 1101 sends a message A to a network device via interface 1102, where the message A is associated with a first reference signal; the message A includes candidate reference signal information, where the candidate reference signal information is used to determine a second reference signal; receives a message B from the network device, where the message B is associated with the second reference signal;

[0259] The first reference signal and the second reference signal are synchronization signal blocks and belong to the same synchronization signal block period.

[0260] Optionally, the chip further includes a memory 1003, and the memory 1003 is used to store program instructions and data necessary for the terminal device.

[0261] Fig.13 A schematic diagram of the structure of a terminal device is provided. For ease of explanation, Fig.13 The main components of the terminal equipment are shown. Fig.13 As shown, the terminal device 1200 includes a processor, a memory, a control circuit, an antenna, and an input-output device. The processor is mainly used to process the communication protocol and communication data, and to control the entire terminal, execute the software program, and process the data of the software program. The memory is mainly used to store the software program and data. The control circuit may include a radio frequency circuit, which is mainly used for converting baseband signals and radio frequency signals and processing radio frequency signals. The antenna is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. The input-output device, such as a touch screen, a display screen, a keyboard, etc., is mainly used to receive data input by the user and output data to the user.

[0262] When the terminal device is turned on, the processor can read the software program in the storage unit, parse and execute the instructions of the software program, and process the data of the software program. When sending data wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the RF circuit. The RF circuit processes the baseband signal to obtain the RF signal and sends the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, and the RF signal is further converted into a baseband signal, and the baseband signal is output to the processor, and the processor converts the baseband signal into data and processes the data.

[0263] For ease of explanation, Fig.13 A memory and a processor are shown. In an actual terminal device, there may be multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiments of the present application.

[0264] As an optional implementation, the processor may include a baseband processor and a central processing unit. The baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire terminal device, execute software programs, and process software program data. Fig.13 The processor in integrates the functions of the baseband processor and the central processing unit. Those skilled in the art will understand that the baseband processor and the central processing unit may also be independent processors, which are interconnected through technologies such as buses. Those skilled in the art will understand that the terminal device may include multiple baseband processors to adapt to different network standards, and the terminal device may include multiple central processing units to enhance its processing capabilities. The various components of the terminal device may be connected through various buses. The baseband processor may also be described as a baseband processing circuit or a baseband processing chip. The central processing unit may also be described as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data may be built into the processor, or may be stored in the storage unit in the form of a software program, and the processor executes the software program to implement the baseband processing function.

[0265] Those skilled in the art may also understand that the various illustrative logical blocks and steps listed in the embodiments of the present application may be implemented by electronic hardware, computer software, or a combination of the two. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the functions described for each specific application, but such implementation should not be understood as exceeding the scope of protection of the embodiments of the present application.

[0266] The present application also provides a computer-readable storage medium having a computer program stored thereon, and the computer-readable storage medium implements the functions of any of the above method embodiments when executed by a computer.

[0267] The present application also provides a computer program product, which implements the functions of any of the above method embodiments when executed by a computer.

[0268] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0269] Those skilled in the art can understand that the various digital numbers such as first and second involved in the present application are distinguished for the convenience of description and are not used to limit the scope of the embodiments of the present application, and also indicate the order of precedence.

[0270] The corresponding relationships shown in each table in the present application can be configured or predefined. The values ​​of the information in each table are examples and can be configured to other values, which are not limited by the present application. When configuring the corresponding relationship between the information and each parameter, it is not necessarily required to configure all the corresponding relationships illustrated in each table. For example, in the table in the present application, the corresponding relationships shown in some rows may not be configured. For another example, appropriate deformation adjustments can be made based on the above table, such as splitting, merging, etc. The names of the parameters shown in the titles of the above tables can also use other names that can be understood by the communication device, and the values ​​or representations of the parameters can also be other values ​​or representations that can be understood by the communication device. When implementing the above tables, other data structures can also be used, such as arrays, queues, containers, stacks, linear lists, pointers, linked lists, trees, graphs, structures, classes, heaps, hash tables or hash tables.

[0271] The predefined in the present application may be understood as defined, predefined, stored, pre-stored, pre-negotiated, pre-configured, solidified, or pre-burned.

[0272] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in 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. Professional and technical personnel can 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.

[0273] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0274] The above is a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A random access method, characterized in that: include: Sending a message 1 to a network device, wherein the message 1 is associated with a first reference signal; receiving a message 2 from the network device, wherein the message 2 is associated with the first reference signal; Sending a message 3 to the network device, wherein the message 3 includes candidate reference signal information, and the candidate reference signal information is used to determine a second reference signal; A message 4 is received from the network device, wherein the message 4 is associated with the second reference signal.

2. The method according to claim 1, characterized in that After receiving the message 4 from the network device, the method further includes one or more of the following: Sending uplink information to the network device, where the uplink information is associated with the first reference signal; receiving downlink information from the network device, where the downlink information is associated with the second reference signal; Sending uplink information to the network device, where the uplink information is associated with the second reference signal; Downlink information is received from the network device, where the downlink information is associated with the first reference signal.

3. The method according to claim 1, characterized in that The message 2 is used to indicate that the reference signal associated with the message 3 is the first reference signal.

4. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: The first reference signal is determined from multiple reference signals according to a measurement result of the reference signal and / or a back-off power corresponding to the reference signal.

5. The method according to claim 4, characterized in that The candidate reference signal information includes one or more of the following: path loss information, an index of the second reference signal, a back-off power corresponding to the reference signal, and a measurement result of the reference signal.

6. A random access method, characterized in that: include: receiving a message 1 from a terminal device, wherein the message 1 is associated with a first reference signal; Sending a message 2 to the terminal device, where the message 2 is associated with the first reference signal; receiving a message 3 from the terminal device, wherein the message 3 includes candidate reference signal information; Determining a second reference signal according to the candidate reference signal information; A message 4 is sent to the terminal device, where the message 4 is associated with the second reference signal.

7. The method according to claim 6, characterized in that After sending the message 4 to the terminal device, the method further includes one or more of the following: receiving uplink information from the terminal device, where the uplink information is associated with the first reference signal; Sending downlink information to the terminal device, where the downlink information is associated with the second reference signal; receiving uplink information from the terminal device, where the uplink information is associated with the second reference signal; Send downlink information to the terminal device, where the downlink information is associated with the first reference signal.

8. The method according to claim 6, characterized in that The message 2 is used to indicate that the reference signal associated with the message 3 is the first reference signal.

9. The method according to any one of claims 6 to 8, characterized in that: The candidate reference signal information includes one or more of the following: path loss information, an index of the second reference signal, a back-off power corresponding to the reference signal, and a measurement result of the reference signal.

10. A communication device, characterized in that: The method comprises a processor and a transceiver, wherein the processor utilizes the transceiver to execute the method according to any one of claims 1 to 5, or executes the method according to any one of claims 6 to 9.

11. A communication device, characterized in that: The method comprises a processor and an interface, wherein the processor executes the method according to any one of claims 1 to 5 or executes the method according to any one of claims 6 to 9 through the interface.

12. A communication device, characterized in that: The method comprises a processor, and when the processor executes the computer program / instructions in the memory, the method according to any one of claims 1 to 5 is executed, or the method according to any one of claims 6 to 9 is executed.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium comprises a computer program / instruction. When the computer program / instruction is executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 5 or the method according to any one of claims 6 to 9.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium comprises a computer program / instruction, and when the computer program / instruction is executed on a computer, the computer is caused to execute the method according to any one of claims 6 to 9, or the method according to any one of claims 6 to 9.

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