Random access process lead code sending method, device and system

Abstract

The invention discloses a method, a device and a system for sending a preamble in a random access process, relates to the technical field of communication, and aims to solve the problem that the time delay of the random access process is prolonged if the terminal equipment increases the transmitting power during preamble retransmission because the downlink path loss measured by the terminal equipment in a UL only TRP scene is higher than the actual uplink path loss. And the efficiency of the random access process is reduced. The method comprises the following steps: the terminal equipment selects a beam for sending a lead code in a random access process, and sends the lead code; wherein the random access process at least comprises initial transmission of the lead code, and at least one retransmission of the lead code under the condition that the RAR is not received in the random access response window after the initial transmission of the lead code; and after the lead code is initially transmitted, under the condition that the RAR is not received in the random access response window, selecting a beam different from the beam for initially transmitting the lead code to perform at least one retransmission of the lead code. The scheme of the invention can be widely applied to the fields of communication technology, artificial intelligence, Internet of Vehicles, smart home networking and the like.

Description

Technical Field

[0001] This application relates to the field of communications, and in particular, to a method, apparatus, and system for transmitting a preamble in a random access process. Background Art

[0002] Random access (RA) is used for the terminal device and the network device to achieve link time synchronization, and for the network device to sense the presence of the terminal device. In the NR system, the terminal device sends a random access preamble on the physical random access channel (PRACH). If the network device correctly receives and demodulates the preamble sent by the terminal device, the network device will send a random access response (RAR) to the terminal device for the preamble; conversely, if the network device does not correctly receive and demodulate the preamble sent by the terminal device, then the terminal device can consider the transmission of this preamble to be a failure if it does not receive an RAR within the random access response window (ra-response window). After the preamble transmission fails, the terminal device can retransmit the preamble, and at the same time, the terminal device can increase the transmission power of the preamble when retransmitting the preamble.

[0003] In a traditional communication system, the transmission point (TRP) can receive the uplink signal sent by the terminal device and send the downlink signal to the terminal device. In order to improve the uplink throughput of the communication system, a new type of network device for receiving uplink signals has been proposed, which is called uplink only TRP or asymmetric TRP. The physical location where this new type of network device is deployed is different from that of the traditional TRP. Naturally, the path loss from the terminal device to the uplink only TRP and the traditional TRP is different. The reference signal for the terminal device to measure the downlink path loss comes from the traditional TRP, so that the downlink path loss measured by the terminal device is greater than the actual uplink path loss. Similarly, the beam used by the uplink only TRP to receive the signal sent by the terminal device is not reciprocal with that of the traditional TRP, and the beam used by the terminal device to receive the downlink signal sent by the traditional TRP is not reciprocal with the beam used to send the uplink signal to the uplink only TRP.

[0004] Because the downlink path loss measured by the terminal device is greater than the actual uplink path loss, the power of the terminal device when sending the preamble is too high. Therefore, if the terminal device preferentially increases the transmission power when retransmitting the preamble, it will lengthen the delay of the random access process and reduce the efficiency of the random access process. Summary of the Invention

[0005] The embodiments of the present application provide a method, device, and system for sending preambles in a random access process, so as to solve the problem that in the UL only TRP scenario, the downlink path loss measured by the terminal device is higher than the actual uplink path loss. If the terminal device increases the transmission power during preamble retransmission, it will lengthen the delay of the random access process and reduce the efficiency of the random access process.

[0006] To achieve the above object, the present application adopts the following technical solutions:

[0007] In a first aspect, the embodiments of the present application provide a method for sending a preamble in a random access process. This method can be executed by a terminal device and a functional module or chip within the terminal device. Taking the terminal device as an example, the method includes: selecting a beam for sending the preamble during the random access process and sending the preamble; where the random access process includes at least the initial transmission of the preamble, and at least one retransmission of the preamble when no RAR is received in the random access response window (ra-response window) after the initial transmission of the preamble; when no RAR is received in the random access response window after the initial transmission of the preamble, select a beam different from the beam of the initial transmission preamble for at least one retransmission of the preamble.

[0008] Based on the method described in the first aspect, compared with the terminal device retransmitting the preamble by increasing the transmission power of the preamble after the initial transmission of the preamble, the terminal device preferentially selects a beam different from the beam of the initial transmission preamble for at least one retransmission of the preamble. In the uplink only TRP scenario, the downlink path loss measured by the terminal device is greater than the actual uplink path loss, resulting in a relatively high transmission power of the terminal device during the initial transmission of the preamble. In this case, the reason why the preamble is not correctly demodulated by the uplink only TRP is more likely that the terminal device did not select the optimal beam direction during the initial transmission, rather than insufficient transmission power. By replacing the beam for preamble retransmission with a beam different from the beam of the initial transmission preamble, the possibility of the terminal device successfully performing random access is increased, achieving the goal of reducing the delay of random access.

[0009] In a possible design, the beams used for the first N - 1 transmissions of the preamble are not used as candidate beams for the Nth transmission of the preamble, where N is an integer greater than 1, N ≤ M, and M is the number of available beams.

[0010] Based on this possible design, when the number of times the terminal device sends the preamble is less than or equal to the number of available beams, the terminal device can traverse different beams of the terminal device to send the preamble, so that when no RAR is received in the random access response window after the initial transmission of the preamble, the terminal device preferentially retransmits the preamble with a beam different from the beam of the initial transmission preamble, improving the probability of successful random access of the terminal device and reducing the delay of random access.

[0011] In a possible design, after the M-th transmission of the preamble during the random access process, if a Random Access Response (RAR) has not been received within the random access response window, the (M + 1)-th transmission of the preamble is performed. The candidate beams for the (M + 1)-th transmission include M beams, and the beams used in the previous N - M - 1 transmissions of the preamble are not candidate beams for the N-th transmission of the preamble, where M < N ≤ 2M and M is the number of available beams.

[0012] Based on this possible design, when the terminal device has transmitted the preamble on all beams and has not received a RAR within the random access response window, the beam for transmitting the preamble during the (M + 1)-th transmission of the preamble can be any available beam of the terminal device. At the same time, when the number of transmissions of the preamble by the terminal device is greater than the number of available beams and less than or equal to twice the number of available beams, the terminal device can traverse the beams of the terminal device again to transmit the preamble, enabling the terminal device to select a beam different from the beam of the initial transmission of the preamble for at least one retransmission of the preamble in the case where a RAR has not been received within the random access response window after the initial transmission of the preamble. Furthermore, when the transmission power of the initial transmission of the preamble is sufficient, by replacing the beam with a beam different from the beam of the initial transmission of the preamble for the retransmission of the preamble, the gain of reducing the random access delay can be obtained.

[0013] In a possible design, the number of preamble power ramping times is counted by a preamble power ramping times counter. For example, after the M-th integer multiple of transmissions, that is, after traversing the available beams to transmit the preamble and a RAR has not been received within the random access response window, the count value of the preamble power ramping times counter is incremented by one, where M is the number of available beams. For example, M can be 2, 3, 4, etc.

[0014] Based on this possible design, it can be determined whether the power of the preamble transmitted this time is higher than the power of the preamble transmitted in the previous time by whether the count value of the preamble power ramping times counter changes. In addition, in the case where a RAR has not been received within the random access response window after each traversal of the available beams, the count value of the preamble power ramping times counter is incremented by one, enabling the terminal device to traverse the available beams to transmit the preamble again with a transmission power higher than the transmission power when traversing the available beams this time. That is, it is preferred to traverse the available beams to transmit the preamble first. If a RAR has not been received after the traversal is completed, it means that the reason for the random access failure may be insufficient transmission power, and the transmission power needs to be increased.

[0015] In a possible design, the number of preamble transmissions is counted by a preamble transmission times counter. For example, if a RAR has not been received within the random access response window after the preamble is transmitted, that is, if a RAR has not been received after each transmission, the count value of the preamble transmission times counter is incremented by one.

[0016] In a possible design, if the count value of the preamble transmission times calculator reaches a preset value, at this time, the media access control layer of the terminal device indicates a random access problem or indicates the failure of the random access process to the upper layer of the terminal device.

[0017] Based on this possible design, the operations that the terminal device needs to perform when the preamble transmission times reach the preset value are given. The reason for the random access problem may be that the preamble selected by the terminal device conflicts with other terminal devices. In this case, the terminal device can resolve the conflict problem by reselecting other preambles.

[0018] In a possible design, receive first indication information for indicating the manner of transmitting a preamble in the random access process. Based on this possible design, the terminal device can receive the indication information and transmit the preamble in the random access process in the indicated manner, so that the terminal device initially transmits and retransmits the preamble in the random access process according to the indication.

[0019] In a possible design, the manner of transmitting the preamble includes at least one retransmission of the preamble by selecting a beam different from the beam of the initially transmitted preamble in the case where no random access response (RAR) is received in the random access response window after initially transmitting the preamble, that is, transmitting the preamble by traversing different beams.

[0020] Based on this possible design, a new manner of transmitting the preamble is given, further enabling the terminal device to transmit the preamble in the manner indicated by the indication information and optimizing the manner of transmitting the preamble. For example, the indication information indicates that the manner of the terminal transmitting the preamble is the method of transmitting the preamble given in this application, or the indication information indicates that the manner of the terminal transmitting the preamble is the method specified by the current radio protocol to transmit the preamble, optimizing the manner of transmitting the preamble.

[0021] In a possible design, receiving the first indication information includes receiving downlink signaling from the network device that is used to trigger the initiation of a random access process to the network device and includes the first indication information. For example, it is possible to receive downlink control information 1_0 (DCI 1_0) of the physical downlink control channel (PDCCH) from the network device, and this DCI 1_0 carries the first indication information.

[0022] Based on this possible design, the first indication information can be carried in the reserved field of the downlink signaling sent by the network device and indicated to the terminal device, so that the first indication information is received without increasing the length of the downlink signaling, saving the overhead of the downlink signaling.

[0023] In a possible design, the first indication information is a 1-bit indication field. Based on this possible design, when the 1-bit indication field is binary bit 0, the downlink signaling including the first indication information is the same as the downlink signaling specified by the current radio protocol, achieving the effect of not affecting the terminal device's parsing of the downlink signaling.

[0024] In a possible design, the first indication information occupies 1 bit in the reserved field of DCI 1_0. When the first indication information is binary bit 1, the terminal device executes the preamble transmission according to the method given in this application; when the first indication information is binary bit 0, the terminal device executes the preamble transmission according to the method specified by the current radio protocol. Further through the foregoing actions, the terminal device can execute the preamble transmission method of the random access procedure given in this application under the indication of the first indication information.

[0025] In a second aspect, an embodiment of this application provides a method for transmitting a preamble in a random access procedure. This method can be executed by a network device and functional modules or chips within the network device. Taking the network device as an example, this method includes: transmitting first indication information, where the first indication information is used to indicate the manner of transmitting a preamble in a random access procedure.

[0026] Based on the method in the second aspect, the network device can implement indicating the manner of transmitting a preamble in a random access procedure, enabling the terminal device to transmit the preamble in the random access procedure according to the indicated manner, and optimizing the manner of transmitting the preamble.

[0027] In a possible design, the manner of transmitting a preamble includes: after initially transmitting the preamble, in the case where a random access response (RAR) is not received within the random access response window, selecting a beam different from the beam of the initially transmitted preamble for at least one retransmission of the preamble.

[0028] Based on this possible design, a new manner of transmitting a preamble is given, further enabling the terminal device to transmit the preamble according to the manner of the preamble indicated by the network device, and optimizing the manner of transmitting the preamble. For example, the network device indicates that the manner of the terminal transmitting the preamble is the method of transmitting the preamble given in this application, or the indication information indicates that the manner of the terminal transmitting the preamble is to transmit the preamble according to the method specified by the current radio protocol, optimizing the manner of transmitting the preamble.

[0029] In a possible design, transmitting the first indication information includes transmitting downlink signaling including the first indication information that is used to trigger the initiation of a random access procedure to the network device. For example, DCI format 1_0 can be sent on the PDCCH, and this DCI format 1_0 carries the first indication information.

[0030] Based on this possible design, the first indication information can be carried in the downlink signaling sent by the network device and indicated to the terminal device, so that the first indication information can be sent to the terminal device without increasing the length of the downlink signaling, saving the overhead of the downlink signaling.

[0031] In a possible design, the first indication information is a one-bit indication field. Based on this possible design, when the one-bit indication field is the binary bit 0, the downlink signaling including the first indication information is the same as the downlink signaling specified by the current radio protocol, achieving the effect of not affecting the terminal device's parsing of the downlink signaling.

[0032] In a third aspect, the present application provides a communication device, which can be a terminal device, a chip or a system-on-chip in the terminal device, or a functional module in the terminal device for implementing the method in the first aspect or any possible design of the first aspect. The communication device can implement the functions performed by the terminal device in the first aspect or any possible design of the first aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device can include a transceiver unit and a processing unit. Among them,

[0033] The processing unit is used to select a beam for transmitting the preamble during the random access process; the random access process at least includes the initial transmission of the preamble, and at least one retransmission of the preamble when no RAR is received in the random access response window after the initial transmission of the preamble; when no RAR is received in the random access response window after the initial transmission of the preamble, select a beam different from the beam of the initial transmission preamble for at least one retransmission of the preamble;

[0034] The transceiver unit is used to transmit the preamble;

[0035] Specifically, the relevant description of the beam for transmitting the preamble can be referred to in the first aspect or any possible design of the first aspect. At the same time, the execution actions of each unit of the communication device can be referred to in the first aspect or any possible design of the first aspect, and will not be elaborated here.

[0036] Fourthly, the present application provides a communication device, which may be a terminal device, a chip or a system-on-chip in the terminal device. The communication device can implement the functions performed by the terminal device in the above first aspect or any possible design of the first aspect, and the functions can be implemented by hardware. In a possible design, the communication device includes a processor and a communication interface. Among them, the processor and the communication interface are used to support the communication device to execute the preamble sending method in the random access process in the first aspect or any possible design of the first aspect. In another possible design, the communication device may further include a memory for storing necessary computer-executable instructions and data of the communication device. When the communication device runs, the processor executes the computer-executable instructions stored in the memory, so that the communication device executes the preamble sending method in the random access process as described in the above first aspect or any possible design of the first aspect.

[0037] Fifthly, the present application provides a communication device, which may be a network device, a chip or a system-on-chip in the network device, or a functional module in the network device for implementing the method in the second aspect or any possible design of the second aspect. The communication device can implement the functions performed by the network device in the above second aspect or any possible design of the second aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include a transceiver unit. Among them,

[0038] The transceiver unit is used to send first indication information, and the first indication information is used to indicate the manner of sending a preamble in the random access process.

[0039] Specifically, the relevant description of the first indication information can be referred to in the second aspect or any possible design of the second aspect. At the same time, the execution actions of each unit of the communication device can be referred to in the second aspect or any possible design of the second aspect, and will not be elaborated here.

[0040] Sixth aspect, the present application provides a communication device, which may be a network device, a chip or a system-on-chip in the network device. The communication device can implement the functions performed by the network device in the second aspect or any possible design of the second aspect, and the functions can be implemented by hardware. In a possible design, the communication device includes a processor and a communication interface. Among them, the processor and the communication interface are used to support the communication device to execute the preamble sending method in the random access procedure in the second aspect or any possible design of the second aspect. In another possible design, the communication device may further include a memory for storing necessary computer-executable instructions and data of the communication device. When the communication device runs, the processor executes the computer-executable instructions stored in the memory, so that the communication device executes the preamble sending method in the random access procedure in the second aspect or any possible design of the second aspect.

[0041] Seventh aspect, the present application provides a communication system, which includes the communication device provided in the third aspect and the communication device provided in the fifth aspect; or, the communication system includes the communication device provided in the third aspect and the communication device provided in the sixth aspect; or, the communication device includes the communication device provided in the fourth aspect and the communication device provided in the fifth aspect; or, the communication system includes the communication device provided in the fourth aspect and the communication device provided in the sixth aspect.

[0042] Eighth aspect, the present application provides a computer-readable storage medium, which stores computer instructions. When the computer instructions run on a computer, the computer is enabled to execute the preamble sending method in the random access procedure in the first aspect or any possible design of the first aspect; or, the computer is enabled to execute the preamble sending method in the random access procedure in the second aspect or any possible design of the second aspect.

[0043] Ninth aspect, the present application provides a computer program product, which includes computer instructions. When the computer instructions run on a computer, the computer is enabled to execute the preamble sending method in the random access procedure in the first aspect or any possible design of the first aspect; or, the computer is enabled to execute the preamble sending method in the random access procedure in the second aspect or any possible design of the second aspect.

[0044] Among them, for the technical effects brought by any design method in the third aspect, the fourth aspect, the seventh aspect to the ninth aspect, reference may be made to the technical effects brought by the first aspect or any possible design of the first aspect, which will not be elaborated here. For the technical effects brought by any design method in the fifth aspect, the sixth aspect, the seventh aspect to the ninth aspect, reference may be made to the technical effects brought by the second aspect or any possible design of the second aspect, which will not be elaborated here. Brief Description of the Drawings

[0045] Figure 1 It is a schematic flow chart of sending a preamble in a random access process;

[0046] Figure 2 It is a schematic diagram of a communication system provided by an embodiment of the present application;

[0047] Figure 3 It is a schematic flow chart of a method for sending a preamble in a random access process provided by an embodiment of the present application;

[0048] Figure 4 It is a schematic flow chart of a method for sending a preamble in a random access process provided by an embodiment of the present application;

[0049] Figure 5 It is a schematic flow chart of a process for sending a preamble provided by an embodiment of the present application;

[0050] Figure 6 It is a schematic flow chart of a process for sending a preamble provided by an embodiment of the present application;

[0051] Figure 7 It is a schematic structural diagram of a communication device provided by an embodiment of the present application;

[0052] Figure 8 It is a schematic structural diagram of a communication device provided by an embodiment of the present application;

[0053] Figure 9 It is a schematic structural diagram of a communication device provided by an embodiment of the present application. Detailed Description of the Embodiments

[0054] Before introducing the embodiments of the present application, some technical terms related to the embodiments of the present application are explained. It should be noted that the following explanations are for the purpose of making the embodiments of the present application easier to understand, and should not be regarded as a limitation on the scope of protection required by the embodiments of the present application.

[0055] Random access (RA) is used to achieve uplink time synchronization between a terminal device and a network device, and to establish an initial connection between the terminal device and the network device. The random access process includes: the terminal device sends a random access preamble on the physical random access channel (PRACH). If the network device correctly receives and demodulates the preamble sent by the terminal device, then the network device will send a random access response (RAR) to the terminal device; conversely, if the network device does not correctly receive and demodulate the preamble sent by the terminal device, then the terminal device can consider the transmission of this preamble to fail if it does not receive an RAR within the random access response window (ra-responsewindow). After the preamble transmission fails, the terminal device can retransmit the preamble, and the terminal device can increase the transmission power of the preamble when retransmitting the preamble.

[0056] The preamble can alternatively be described as a random access preamble or a preamble sequence or a preamble or random access request information. The preamble can be carried in the physical random access channel (PRACH) and sent to the network device. The preamble can be configured by the network device and specified for the terminal device, or the terminal device can randomly select it from the preamble set.

[0057] The random access response window can also be referred to as the random access response time window, or the RAR time window. The random access response window can be a time period / time window used to limit the reception of the RAR. Receiving an RAR within this random access response window means that the random access is successful, and not receiving an RAR within this random access response window or the random access response window timing out without receiving an RAR means that the random access fails. The configuration information of the random access response window is notified by the network device to the terminal device through the broadcast system message.

[0058] The preamble can alternatively be described as message 1 (message1, MSG1); the RAR can alternatively be described as message 2 (message2, MSG2).

[0059] Among them, the transmission power of the preamble transmitted by the terminal device is determined by the maximum transmission power of the terminal device, the expected reception power pre-configured by the MAC layer, and the path loss between the terminal device and the network device. Exemplarily, taking the case where the terminal device initially transmits a preamble to the network device in the bandwidth part (bandwidth parth, BWP) b of carrier f in cell c as an example, the transmission power P of the preamble initially transmitted by the terminal device prach,b,f,c(i) satisfies the following formula (1):

[0060] P prach,b,f,c (i) = min{P cmax,f,c (i), P prach,target,f,c + PL b,f,c}} dBm (1)

[0061] In formula (1), P cmax,f,c (i) is the maximum transmission power of the terminal device, P prach,target,f,c is the expected received power of the PRACH, which is determined by the high-layer parameter PREAMBLE_RECEIVED_TARGET_POWER, and PL b,f,c is the path loss between the terminal device and the network device. P prach,b,f,c (i) is the minimum value among the maximum transmission power of the terminal device, the sum of the expected received power of the PRACH and the path loss between the terminal device and the network device.

[0062] Currently, if the terminal device does not receive the RAR sent by the network device in the random access response window after initially transmitting the preamble, it is considered that the initial transmission of the preamble fails. At this time, the terminal device can retransmit the preamble by increasing the transmission power of the preamble, or by reselecting a new beam to retransmit the preamble. If reselecting a new beam to retransmit the preamble, the transmission power of the preamble remains unchanged; if increasing the transmission power of the preamble to retransmit the preamble, then the transmission power PREAMBLE_RECEIVED_TARGET_POWER of the retransmitted preamble satisfies the following formula (2):

[0063] PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA.

[0064] Among them, preambleReceivedTargetPower is the expected received power of the previous preamble transmission, DELTA_PREAMBLE is the power offset value related to the preamble format, PREAMBLE_POWER_RAMPING_COUNTER is the count value of the preamble power ramping counter, PREAMBLE_POWER_RAMPING_STEP is the increasing step of the transmission power each time the preamble is retransmitted, and POWER_OFFSET_2STEP_RA is the offset value related to the random access (RA) type.

[0065] If a new beam preamble is reselected for retransmission, the transmission power of the preamble remains unchanged. It can be understood that the terminal device switches the beam to send the preamble. At the same time, the preamble power ramp count counter does not count when the preamble is sent this time, that is, the count value of the preamble power ramp count counter remains unchanged, and the transmission power of the preamble sent by the terminal device this time remains unchanged compared with the transmission power of the preamble sent in the previous time.

[0066] Exemplarily, as Figure 1 shown, assume that the beams available for the terminal device to send the preamble include two beams with different transmission directions. The terminal device has performed 1 initial transmission of the preamble (or called initial transmission) and 4 retransmissions of the preamble for the random access process. Among them, the beam of the first retransmission preamble is the same as that of the initial transmission preamble, but the transmission power of the first retransmission preamble is higher than that of the initial transmission preamble. Therefore, the count value of the preamble power ramp count counter increases from 1 to 2; the beam of the second retransmission preamble is the same as that of the first retransmission preamble, but the transmission power of the second retransmission preamble is higher than that of the first retransmission preamble. Therefore, the count value of the preamble power ramp count counter increases from 2 to 3; the beam of the third retransmission preamble is different from that of the second retransmission preamble, but the transmission power of the third retransmission preamble does not increase compared with that of the second retransmission preamble. Therefore, the preamble power ramp count counter does not count and its count value remains 3; the beam of the fourth retransmission preamble is the same as that of the third retransmission preamble, but the transmission power of the fourth retransmission preamble is higher than that of the third retransmission preamble. Therefore, the count value of the preamble power ramp count counter increases from 3 to 4.

[0067] The above random access process can be applied to various communication systems. For example, it can be applied to a communication system including a terminal device, a traditional base station, and an uplink only TRP. In this communication system, since the uplink only TRP is used to receive the uplink signal sent by the terminal device but does not support downlink transmission, that is, it does not support sending downlink signals and / or data to the terminal device, it is necessary to rely on the traditional base station to send downlink signals and / or data to the terminal device. The physical locations where the traditional base station and the uplink only TRP are deployed are different, resulting in different path losses from the terminal device to the uplink only TRP and to the traditional base station. The reference signal for the terminal device to measure the downlink path loss comes from the traditional base station. Therefore, the downlink path loss measured by the terminal device is greater than the actual uplink path loss. Similarly, the communication environments and communication methods supported by the traditional base station and the uplink only TRP are different, resulting in non-reciprocity between the uplink beam between the terminal device and the uplink only TRP and the downlink beam between the traditional base station and the terminal device. When the terminal device transmits a preamble, it needs to select a beam from several configured beams for preamble transmission. In the aforementioned communication system, since the downlink path loss measured by the terminal device is greater than the actual uplink path loss, when using the above formula (1) to determine the transmission power of the initial transmission preamble, the transmission power of the initial transmission preamble of the terminal device is too high. At this time, if the terminal device needs to retransmit the preamble, the reason for the failure of the previous preamble transmission is more likely to be that the optimal beam direction is not selected rather than insufficient transmission power. If the transmission power is increased during preamble retransmission, the delay of the random access process will be lengthened, reducing the efficiency of the random access process.

[0068] To solve the problem that in the UL only TRP scenario, the measured downlink path loss of the terminal device is higher than the actual uplink path loss. If the terminal device increases the transmission power during preamble retransmission, it will lengthen the delay of the random access process and reduce the efficiency of the random access process. This application provides a method for sending preambles in the random access process, which includes: the terminal device selects a beam for initial preamble transmission, and if it does not receive a RAR in the random access response window after the initial preamble transmission, it selects a beam again for at least one retransmission of the preamble; among them, if it does not receive a RAR in the random access response window after the initial preamble transmission, it selects a beam different from the beam of the initial preamble for at least one retransmission of the preamble. In the uplink only TRP scenario, the measured downlink path loss of the terminal device is greater than the actual uplink path loss, resulting in a relatively high transmission power of the terminal device during the initial preamble transmission. At this time, the reason why the preamble is not correctly demodulated by the uplink only TRP is more likely that the terminal device does not select the optimal beam direction during the initial transmission, rather than insufficient transmission power. Thus, compared with the terminal device preferentially retransmitting the preamble by increasing the transmission power of the preamble after the initial preamble transmission, the terminal device preferentially selects a beam different from the beam of the initial preamble for at least one retransmission of the preamble, enabling the terminal device to retransmit the preamble by changing a beam different from the beam of the initial preamble when the transmission power of the initial preamble is sufficient, improving the possibility of the terminal device successfully randomly accessing and achieving the goal of reducing the delay of random access.

[0069] The following describes the method for sending preambles in the random access process provided by the embodiments of this application in conjunction with the accompanying drawings of the specification.

[0070] The technical solution of the embodiment of the present application can be applied to various communication systems, which can be a third generation partnership project (3GPP) communication system, for example, a long term evolution (LTE) system, or a fifth generation (5G) mobile communication system, a new radio (NR) system, a beyond 5G (B5G) mobile communication system, a 6th-generation (6G) mobile communication system, a new radio vehicle to everything (NR V2X) system. It can also be applied to a system with a hybrid network of LTE and 5G, or a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, the Internet of Things (IoT), and other next-generation communication systems. It can also be a non-3GPP communication system, without limitation. The following takes Figure 2 the communication system shown as an example to describe the preamble sending method for the random access procedure provided by the embodiment of the present application.

[0071] The technical solution of the embodiment of the present application can be applied to various communication scenarios, for example, one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communications (mMTC), D2D, V2X, and IoT and other communication scenarios.

[0072] The communication system applicable to the technical solution of the embodiment of the present application may include a terminal device and a network device. It can be understood that the terminal device and the network device can communicate directly or through the forwarding of other devices. The embodiment of the present application does not make specific limitations on this. Figure 2 FIG. is a schematic diagram of a communication system provided for an embodiment of the present application. As Figure 2 shown, the communication system 20 may include: a network device and a terminal device.

[0073] It can be understood that the above Figure 2This is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solutions provided by this application. Those skilled in the art should understand that in the specific implementation process, the communication system 20 may also include fewer devices than Figure 2 shown, or the communication system 20 may further include other devices. At the same time, the number of devices in the communication system 20 can also be determined according to specific needs without limitation. The devices in the Figure 2 shown system will be described below.

[0074] The terminal equipment can be a user equipment (UE), or a mobile station (MS), or a mobile terminal (MT), etc., including handheld devices, vehicle-mounted devices, wearable devices or computing devices with wireless communication functions. Specifically, the terminal equipment can be a mobile phone, a tablet computer or a computer with wireless transceiver functions, and can also be a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in smart city, smart home, vehicle-mounted terminal, etc. In the embodiments of this application, the device for implementing the functions of the terminal equipment can be the terminal equipment, or a device capable of supporting the terminal equipment to implement such functions, such as a chip system (for example, a chip, or a processing system composed of multiple chips) or a modem. Below, taking the device for implementing the functions of the terminal equipment as the terminal equipment as an example, the preamble sending method in the random access process provided by the embodiments of this application will be described.

[0075] A network device is mainly used to implement functions such as resource scheduling, radio resource management, and radio access control of a terminal device. It is a device in a radio access network (RAN) that connects a terminal device to a wireless network. The RAN can be connected to a core network (for example, it can be the core network of LTE or the core network of 5G, etc.). The network device can be an evolved Node B (eNB or eNodeB) in LTE, or a base station in a 5G network or a future evolved public land mobile network (PLMN), or a base station that supports unilateral transmission (for example, an uplink only TRP or an asymmetric TRP that supports uplink transmission but not downlink transmission), or a broadband network gateway (BNG), or an aggregation switch or a non-3GPP access device; or the network device in the embodiments of the present application can also be a radio controller in a cloud radio access network (CRAN); or a transmission and reception point (TRP), or a device including a TRP, etc. The embodiments of the present application do not make specific limitations in this regard. Optionally, the network device in the embodiments of the present application can include various forms of base stations, such as: macro base stations, micro base stations (also called small stations), relay stations, access points, etc. The embodiments of the present application do not make specific limitations in this regard. In the embodiments of the present application, the device for implementing the functions of the network device can be the network device, or a device that can support the network device to implement this function, such as a chip system (for example, a single chip or a processing system composed of multiple chips) or a modem. Hereinafter, taking the device for implementing the functions of the network device as the network device as an example, the preamble sending method for the random access process provided by the embodiments of the present application will be described.

[0076] Optionally, Figure 2 each device (such as a terminal device, a network device) in can also be referred to as a communication device, which can be a general device or a special device. The embodiments of the present application do not make specific limitations in this regard.

[0077] Optionally, the present application Figure 2The related functions of each device in [the context] can be implemented by one device, or jointly implemented by multiple devices, or implemented by one or more functional modules within one device. The embodiments of the present application do not make specific limitations on this. It can be understood that the above functions can be either network elements in hardware devices, or software functions running on dedicated hardware, or a combination of hardware and software, or virtualized functions instantiated on a platform (such as a cloud platform).

[0078] Next, in combination with Figure 2 the communication system shown, the preamble sending method for the random access process provided by the embodiments of the present application will be described. Actions, terms, etc. involved between the following embodiments can be referred to each other. The message names or parameter names in the messages exchanged between devices in each embodiment are just examples, and other names can also be used in specific implementations. For example, "corresponding" in the following embodiments can be replaced and described as "associated", etc., and "sending" in the following embodiments can be replaced and described as "transmitting", etc. Figure 3 is a schematic flowchart of a preamble sending method for the random access process provided by the embodiments of the present application. As Figure 3 shown, it may include step S301 - step S302:

[0079] S301: The terminal device selects a beam for sending the preamble during the random access process.

[0080] Among them, the terminal device can be Figure 2 the terminal device shown. This terminal device can be in a connected state, an idle state, or an inactive state, without limitation. This terminal device can include M available beams (or referred to as uplink beams). These M available beams can be replaced and described as candidate beams. The terminal device can select a beam from these M available beams to send the preamble. M is a natural number greater than 1. The value of M depends on the capabilities of the terminal device.

[0081] Among them, the random access process includes at least the initial transmission of the preamble, and at least one retransmission of the preamble in the case where no RAR is received in the random access response window after the initial transmission of the preamble. In the present application, the initial transmission of the preamble can refer to the first sending of the preamble, the first transmission of the preamble, or the initial transmission, etc. The retransmission can refer to sending the preamble again after the initial transmission of the preamble. In the case where the number of times of sending the preamble is numbered continuously starting from 1, the initial transmission can refer to the first sending, and the retransmission can refer to the Nth sending, where N is an integer greater than 1 or understood as N is an integer greater than or equal to 2. The Nth sending can also be replaced and described as the (N - 1)th retransmission.

[0082] It should be understood that the random access process at least includes the initial transmission of the preamble, and when no RAR is received in the random access response window after the initial transmission of the preamble, at least one retransmission of the preamble can mean that: the random access process is the initial transmission of the preamble, or the random access process is the initial transmission of the preamble and at least one retransmission of the preamble. At least one retransmission can include one retransmission and multiple retransmissions, and multiple retransmissions can include but are not limited to two retransmissions or three retransmissions, etc.

[0083] In this application, when no RAR is received in the random access response window after the initial transmission of the preamble, at least one retransmission of the preamble is performed by selecting a beam different from the beam of the initial transmission of the preamble, so as to transmit the preamble through different beams and improve the random access success probability. Selecting a beam different from the beam of the initial transmission of the preamble for at least one retransmission of the preamble can be replaced by describing that a beam is selected from candidate beams for retransmission of the preamble, and the candidate beams can be beams different from the initial transmission of the preamble; or, it can be replaced by describing that the preamble is transmitted through different beams or the terminal device traverses and selects different beams for transmitting the preamble during the random access process. Or, it can be replaced by describing that when no RAR is received in the random access response window after the initial transmission of the preamble, the terminal device preferentially traverses different beams to retransmit the preamble, or it can be replaced by describing that when no RAR is received in the random access response window after the first transmission of the preamble, the terminal device preferentially retransmits the preamble on other beams, or it can be replaced by describing that when no RAR is received in the random access response window after the first transmission of the preamble and the terminal device has multiple beams, the terminal device preferentially retransmits the preamble on other beams except the beam of the first transmission of the preamble, or it can be replaced by describing that when no RAR is received in the random access response window after the first transmission of the preamble and the terminal device has M available beams, the terminal device preferentially retransmits the preamble on other beams except the beam of the first transmission of the preamble among the M beams.

[0084] Taking the case where the number of available beams included in the terminal device is M as an example, when the number N of times of transmitting the preamble is an integer greater than 1 and the number N of times of transmitting the preamble is less than or equal to the number M of available beams of the terminal device, the beams used for the first N - 1 times of transmitting the preamble are not used as candidate beams for the Nth time of transmitting the preamble. After the Mth transmission of the preamble during the random access process and still not receiving the RAR in the random access response window, the (M + 1)th transmission of the preamble is performed, that is, the second round of traversing different beams to transmit the preamble is started. The candidate beams for the (M + 1)th transmission include M beams. In other words, the candidate beams during the second round of traversal are M beams. At this time, the number N of times of transmitting the preamble is greater than the number M of available beams of the terminal device and less than or equal to 2M. The beams used for the first N - M - 1 times of transmitting the preamble during the second round of traversal are not used as candidate beams for the Nth time of transmitting the preamble. And so on, after the (K * M)th transmission and still not receiving the RAR in the random access response window, the ((K * M) + 1)th transmission of the preamble is performed, that is, the (K + 1)th round of traversing different beams to transmit the preamble is started, where K is an integer greater than or equal to 2.

[0085] In this application, the description of beam replaceability is the spatial domain transmission filter, or the uplink beam, or the uplink spatial filter. The number of available beams of the terminal device, the description of replaceability is the number of beams of the terminal device, or the number of spatial domain transmission filters of the terminal device, or the number of available spatial domain transmission filters of the terminal device. Different beams correspond to different numbers or index numbers or beam index numbers. The traversal order of different rounds can be the same or different. For example, in the first round, different beams are traversed in ascending order of numbers, and in the second round, different beams are traversed in descending order of numbers, etc., without limitation.

[0086] Specifically, taking the case where the number of available beams included in the terminal device is M as an example, S301 may include:

[0087] In the case where the random access process is the initial transmission of the preamble, the M available beams are used as candidate beams, and the terminal device selects one beam from the M available beams to be used for the initial transmission of the preamble. The beam selected by the terminal device for transmitting the preamble can be any one of the available beams of the terminal device.

[0088] In the case where the random access process is the initial transmission of the preamble and the first retransmission of the preamble, the terminal device selects one beam from the M available beams as the candidate beam to send the initial transmission of the preamble. When the RAR is not received in the random access response window after the initial transmission of the preamble, the M-1 beams different from the beam of the initial transmission of the preamble are used as candidate beams, and one beam is selected from the M-1 candidate beams for the first retransmission. The candidate beams for the first retransmission include the other beams in the available beams except the beam of the initial transmission of the preamble.

[0089] In the case where the random access process is the initial transmission of the preamble and multiple retransmissions of the preamble, the terminal device selects one beam from the available beams to send the initial transmission of the preamble. When the RAR is not received in the random access response window after the initial transmission of the preamble, different beams are selected from the other beams in the available beams except the beam that sent the preamble for the first retransmission of the preamble. When the RAR is not received in the random access response window after the first retransmission, the M-2 beams different from the beam of the initial transmission of the preamble and the beam of the first retransmission of the preamble are used as candidate beams, and one beam is selected from the M-2 candidate beams for the second retransmission of the preamble. The candidate beams for the second retransmission include the other beams in the available beams except the beam of the initial transmission of the preamble and the beam of the first retransmission of the preamble. And so on, traversing the M different beams for multiple retransmissions.

[0090] S302: The terminal device sends the preamble.

[0091] Specifically, the terminal device can send the preamble to the network device. Correspondingly, the network device receives the preamble.

[0092] In this application, the terminal device can determine the transmission power of the preamble and send the preamble with the determined transmission power. The transmission power of the initial transmission of the preamble can be the preset transmission power or the transmission power determined according to the above formula (1). When the RAR is not received in the random access response window after the initial transmission of the preamble, the same transmission power as the transmission power of the initial transmission of the preamble is selected for at least one retransmission of the preamble.

[0093] For example, taking the case where the number of available beams included in the terminal device is M, the first M preambles including the initial preamble are transmitted with the same transmission power as the transmission power of the initial preamble. After transmitting the M preambles and still not receiving the RAR in the random access response window, the transmission power is increased. For example, a new transmission power is determined using the above formula (2), and the (M + 1)-th to 2M-th transmissions of the preamble are performed with the new transmission power, that is, the second round of traversing different beams to transmit the preamble is started. The transmission power when traversing different beams in the second round to transmit the preamble is higher than the transmission power when traversing different beams in the first round (i.e., the transmission power of the initial preamble). And so on, after the K*M-th transmission and still not receiving the RAR in the random access response window, the (K*M + 1)-th to (K + 1)*M-th transmissions of the preamble are performed with a transmission power higher than the previous K times, where K is an integer greater than or equal to 2.

[0094] Based on Figure 3 According to the method shown above, when the terminal device does not receive the RAR in the random access response window after transmitting the initial preamble, it selects at least one beam different from the beam of the initial preamble to retransmit the preamble, so that the terminal device can retransmit the preamble by changing to a beam different from the beam of the initial preamble when the transmission power of the initial preamble is too high, which improves the possibility of the terminal device successfully accessing randomly and achieves the goal of reducing the delay of random access.

[0095] In this application, it can be determined whether the transmission power of the preamble transmitted this time is higher than the transmission power of the preamble transmitted in the previous time by whether the count value of the preamble power ramping counter changes. Every time after transmitting M preambles and still not receiving the RAR in the random access response window, the count value of the preamble power ramping counter is incremented by one, where M is the number of available beams. For example, when transmitting the M-th preamble, the count value of the preamble power ramping counter is 1. After transmitting the M-th preamble and still not receiving the RAR in the random access response window, the count value of the preamble power ramping counter is incremented by one, and the count value of the preamble power ramping counter is 2. When transmitting the 2M-th preamble, the count value of the preamble power ramping counter is 2. After transmitting the 2M-th preamble and still not receiving the RAR in the random access response window, the count value of the preamble power ramping counter is incremented by one, and the count value of the preamble power ramping counter is 3. And so on, after the K*M-th transmission and still not receiving the RAR in the random access response window, the count value of the preamble power ramping counter is incremented by one, and the count value of the preamble power ramping counter is K.

[0096] It should be understood that the present application does not limit the initial value of the count value of the preamble power ramping count counter when the terminal device initially transmits the preamble. For example, when the terminal device initially transmits the preamble, the initial value of the count value of the preamble power ramping count counter is 1; or, when the terminal device initially transmits the preamble, the initial value of the count value of the preamble power ramping count counter is 0, which is not restricted.

[0097] Optionally, the preamble power ramping count counter can be pre-configured in the terminal device.

[0098] In the present application, the preamble transmission times can be counted by a preamble transmission counter. The count value of the preamble transmission counter is equal to the preamble transmission times. Each time a preamble is transmitted, the count value of the preamble transmission counter is incremented by one. For example, when the preamble is transmitted for the (N - 1)th time, the count value of the preamble transmission counter is N - 1. When the preamble is transmitted for the Nth time, the count value of the preamble transmission counter is incremented by one, and the count value of the preamble transmission counter is N.

[0099] Optionally, the preamble transmission counter can be pre-configured in the terminal device.

[0100] Optionally, in the initial situation or initialization state, the count value of the preamble transmission counter is 1. When the preamble is initially transmitted, the count value of the preamble transmission counter is 1. After the preamble is initially transmitted and no RAR is received in the random access response window, the first preamble retransmission is performed, and the count value of the preamble transmission counter is incremented by one, and the count value of the preamble transmission counter is 2. After the first preamble retransmission, if an RAR is received in the random access response window, the random access is successful, and the preamble transmission counter stops counting. If no RAR is received in the random access response window, the second preamble retransmission is performed, and the count value of the preamble transmission counter is incremented by one, and the count value of the preamble transmission counter is 3, and so on. After the (K * M)th transmission and no RAR is received in the random access response window, the (K * M + 1)th preamble transmission is performed, and the count value of the preamble transmission counter is incremented by one, and the count value of the preamble transmission counter is K * M + 1.

[0101] It should be understood that in the initial situation or initialization state, the present application does not limit the initial value of the count value of the preamble transmission times counter. For example, in the initial situation or initialization state, if the initial value of the count value of the preamble transmission times counter is 1, then when the terminal device initially transmits the preamble, the count value of the preamble transmission times counter is 1; or, in the initial situation or initialization state, if the initial value of the count value of the preamble transmission times counter is 0, then when the terminal device initially transmits the preamble, the count value of the preamble transmission times counter is 0, which is not restricted.

[0102] Optionally, when the terminal device is in the idle state or inactive state, the terminal device can initiate a random access procedure actively and execute Figure 3 the method shown. When the terminal device is in the connected state, the terminal device can receive downlink signaling from the network device and initiate a random access procedure in response to the received downlink signaling. This downlink signaling can be a physical downlink control channel signaling (physical downlink control channel order, PDCCH order).

[0103] The PDCCH order can include a DCI format identifier (Identifier for DCI formats), a frequency domain resource allocation (Frequency Domain Resource Assignment), a random access preamble index (Random Access Preamble index), an uplink / supplementary uplink indicator (UL / SUL indicator), an SSB index (SS / PBCH index), a random access mask index (PRACH Mask index), and a reserved bits field. The number of bits occupied by the length of each field is shown in Table 1. Among them, for the detailed interpretation of each field in Table 1, reference can be made to the description of 3GPP TS 38.212 V18.0.0 (2023-09) 7.3.1.2.1 Format 1_0.

[0104] Table 1

[0105]

[0106] Optionally, Figure 3 the preamble transmission method of the random access procedure shown can be pre-configured or agreed upon by the protocol, or can be indicated to the terminal device by other devices. For example, it can be indicated to the terminal device by the network device.

[0107] Figure 3 The preamble transmission method of the random access procedure shown can further include the following steps before S301:

[0108] S300: The network device sends first indication information. Correspondingly, the terminal device receives the first indication information.

[0109] The first indication information is used to indicate the way of sending a preamble in the random access process and is 1 bit. The way of sending a preamble includes retransmitting the preamble at least once using a beam different from the beam of the initial transmission preamble when no RAR is received in the random access response window after the initial transmission of the preamble.

[0110] The network device sending the first indication information includes: The network device sends downlink signaling for triggering a random access process to the network device, and the downlink signaling includes the first indication information.

[0111] The terminal device receiving the first indication information includes: The terminal device receives downlink signaling from the network device, and the downlink signaling is used to trigger a random access process to the network device and includes the first indication information.

[0112] Exemplarily, the downlink signaling sent by the network device for triggering a random access process to the network device is an indication field with 1 bit for the first indication information, and the 1-bit indication field can be a newly added field with a length of 1 bit. For example, the downlink signaling can be a PDCCH order, and the downlink signaling is shown in Table 2.

[0113] Table 2

[0114]

[0115] The relevant descriptions of the DCI format identifier (Identifier for DCI formats), frequency domain resource allocation (Frequency Domain Resource Assignment), random access preamble index (Random Access Preamble index), uplink / supplementary uplink indicator (UL / SUL indicator), SSB index (SS / PBCH index), and PRACH mask index fields in Table 2 are the same as the relevant descriptions of the corresponding fields in Table 1, and will not be elaborated here.

[0116] The newly added field in Table 2 has a length of 1 bit and is used to indicate the way of sending a preamble in the random access process. The way of sending a preamble includes retransmitting the preamble at least once using a beam different from the beam of the initial transmission preamble when no RAR is received in the random access response window after the initial transmission of the preamble.

[0117] In Table 2, the length of the Reserved bits field is 11 bits or 9 bits. When used for spectrum sharing, the length of this field is 11 bits; otherwise, it is 9 bits.

[0118] Optionally, when the count value of the preamble transmission times counter of the terminal device reaches a preset value, to facilitate the upper layer to perceive the underlying situation and then adopt a reasonable communication strategy / communication measure based on the underlying situation. Figure 3 The preamble transmission method for the random access process shown may further include the following step S303:

[0119] S303: When the count value of the preamble transmission times counter of the terminal device reaches the preset value, the media access control layer of the terminal device indicates a random access problem or a random access process failure to the upper layer of the terminal device.

[0120] Wherein, the count value of the preamble transmission times counter of the terminal device is the value of the parameter PREAMBLE_TRANSMISSION_COUNTER used to determine the preamble transmission times in the terminal device.

[0121] Wherein, the preset value is the value of the parameter PREAMBLE_TRANS_MAX, which is the maximum number of preamble transmissions configured by the network device. Before the terminal device performs the random access process, it will obtain the preset value set by the network device in advance through SIB2.

[0122] Wherein, the media access control (MAC) layer of the terminal device is used to initiate the random access process or indicate a random access problem or a random access process failure to the upper layer when the random access fails.

[0123] Specifically, a random access failure includes that the count value of the preamble transmission times counter reaches the preset value. Therefore, when the count value of the preamble transmission times counter of the terminal device reaches the preset value, the MAC layer of the terminal device will indicate a random access problem or a random access process failure to the upper layer. Whether the terminal device will initiate a random access process again later is determined by the upper layer of the terminal device.

[0124] Figure 3 There may be multiple network devices. Taking the network device including a traditional base station and an uplink only TRP as an example, and the terminal device including 2 available beams (Beam 1 and Beam 2) as an example, in combination with Figure 4 For Figure 3 The preamble transmission method for the random access process shown will be introduced. Figure 4 It is a schematic flowchart of a preamble transmission method for a random access process provided by an embodiment of this application. As Figure 4 shown, this method may include:

[0125] S400: The traditional base station sends a PDCCH command to the terminal device. Correspondingly, the terminal device receives the PDCCH command.

[0126] Among them, the traditional base station triggers the PDCCH command by sending downlink control information (DCI) format 1_0 through a beam, so that the terminal device and the uplink only TRP achieve uplink synchronization. DCI format 1_0 is often used to schedule the physical downlink shared channel (PDSCH) to the terminal device in the cell. DCI format 1_0 can be scrambled with a cyclic redundancy checksum (CRC) using a radio network temporary identifier (RNTI). The RNTI is used to represent the definition of the terminal device at different stages in the radio cell, paging, power control sent by the network device, and system message decoding. When the terminal device decodes the CRC scrambled with the DCI format 1_0 and the cell-radio network temporary identifier (C-RNTI) and the "Frequency Domain Resource Assignment" field is all 1s, the DCI format 1_0 is used for the random access process initiated by the PDCCH command.

[0127] Among them, the PDCCH command is used to trigger a random access process to the uplink only TRP. The PDCCH command includes a first indication information. The first indication information is 1 bit and is used to indicate the way of sending a preamble in the random access process. The way of sending a preamble includes retransmitting the preamble at least once with a beam different from the beam of the initial transmission preamble when no random access response (RAR) is received in the random access response window after the initial transmission of the preamble. For example, the PDCCH command includes the fields shown in Table 2, and the first indication information is a newly added field of 1 bit.

[0128] A possible case is that the first indication information occupies 1 bit in the PDCCH command. One bit is used to indicate the manner of transmitting the preamble in the random access process, whether to select at least one retransmission of the preamble with a beam different from that of the initial transmission preamble in the case where the random access response (RAR) is not received in the random access response window after transmitting the initial transmission preamble. For example, the binary bit 1 can indicate that in the random access process, in the case where the RAR is not received in the random access response window after transmitting the initial transmission preamble, at least one retransmission of the preamble is performed with a beam different from that of the initial transmission preamble; the binary bit 0 can indicate that in the random access process, in the case where the RAR is not received in the random access response window after transmitting the initial transmission preamble, the preamble is retransmitted by increasing the transmission power of the preamble; or, for example, the binary bit 0 can indicate that in the random access process, in the case where the RAR is not received in the random access response window after transmitting the initial transmission preamble, at least one retransmission of the preamble is performed with a beam different from that of the initial transmission preamble; the binary bit 1 can indicate that in the random access process, in the case where the RAR is not received in the random access response window after transmitting the initial transmission preamble, the preamble is retransmitted by increasing the transmission power of the preamble, etc., without limitation.

[0129] It should be understood that S400 is an optional execution. When a terminal device in the connected state needs to trigger a random access process to the network device through a PDCCH command, S400 is executed; when a terminal device in the idle state or inactive state initiates a random access process to the network device actively, S400 is not executed.

[0130] Exemplarily, the cases where a terminal device in the idle state or inactive state initiates a random access process to the network device actively may include at least one of the following scenarios: (1) Establishing a radio connection during initial access: The terminal device changes from the RRC_IDLE state to the RRC_CONNECTED state; (2) RRC connection re-establishment procedure: So that the terminal device can re-establish a radio connection after a radio link failure. (3) Handover: The terminal device needs to establish uplink synchronization with a new cell. (4) When the terminal device is in the RRC_CONNECTED state and uplink data arrives, the uplink is in an "out-of-sync" state.

[0131] Exemplarily, the scenarios where a terminal device in the connected state needs a PDCCH command to trigger a random access procedure to the network device include at least one of the following scenarios: (1) The terminal device is in the RRC_CONNECTED state, and when downlink data arrives, the uplink is in an "out-of-sync" state. (2) The terminal device is in the RRC_CONNECTED state, and the configuration information of the traditional base station has changed.

[0132] S401: The terminal device transmits the preamble to the uplink only TRP for the first time. Correspondingly, the uplink only TRP receives and decodes the preamble.

[0133] Among them, the uplink only TRP is a base station that supports uplink transmission but not downlink transmission.

[0134] Among them, the terminal device transmitting the preamble to the uplink only TRP for the first time includes: The terminal device selects a preamble from the preamble sequence. Referring to Figure 5 , the terminal device selects beam 1 from 2 available beams and transmits the selected preamble to the uplink only TRP at the transmission power P0 of the preamble. Alternatively, the terminal device selects beam 1 from 2 available beams and transmits the dedicated preamble allocated by the network device to the uplink only TRP at the transmission power P0 of the preamble. At this time, the count value of the preamble power ramp-up times counter is initialized to 1, and the count value of the preamble transmission times counter is initialized to 1.

[0135] Specifically, when the value of the Random Access Preamble index field in the PDCCH command is 0 or the terminal device actively initiates a random access procedure to the network device, the terminal device randomly selects a preamble from the preamble sequence and selects beam 1 from 2 available beams to transmit the selected preamble to the uplink only TRP; when the value of the Random Access Preamble index field in the PDCCH command is non-zero, the network device has allocated a dedicated preamble for the terminal device, and the dedicated preamble can be indicated by the Random Access Preamble index field in the PDCCH command. At this time, the terminal device selects beam 1 from 2 available beams and transmits the dedicated preamble indicated by the value of the Random Access Preamble index field in the PDCCH command to the uplink only TRP.

[0136] Exemplarily, in the case where the terminal device actively initiates a random access procedure to the uplink only TRP, the terminal device randomly selects a preamble with a preamble index of 15 from the preamble sequence, and selects beam 1 to transmit the preamble with a preamble index of 15 to the uplink only TRP for the first time. Correspondingly, the uplink only TRP receives and decodes the preamble with a preamble index of 15 transmitted by the terminal device for the first time.

[0137] S402: After the terminal device transmits the preamble for the first time, it listens for the PDCCH in the random access response window to receive the RAR sent by the traditional base station.

[0138] Herein, the traditional base station refers to a base station that supports both uplink transmission and downlink transmission.

[0139] It should be understood that the interaction between the uplink only TRP and the traditional base station in the embodiments of the present application is ideal, that is, there is no transmission delay between the uplink only TRP and the traditional base station.

[0140] Among them, the PDCCH carries scheduling and other control information, including transmission format, resource allocation, uplink scheduling permission power control, and uplink retransmission information, etc.

[0141] Among them, after the terminal device transmits the preamble for the first time, it listens for the PDCCH in the random access response window to receive the RAR sent by the traditional base station, including: the terminal device transmits the preamble for the first time to the uplink only TRP with the transmission power P0 of the preamble for the first time in beam 1. If the uplink only TRP receives and successfully decodes the preamble transmitted by the terminal device for the first time, the traditional base station will send an RAR to the terminal device. Correspondingly, the terminal device will receive the RAR in the random access response window after transmitting the preamble for the first time; if the uplink only TRP receives but fails to successfully decode the preamble transmitted by the terminal device for the first time, the traditional base station will not send an RAR to the terminal device. Correspondingly, the terminal device will not receive the RAR in the random access response window after transmitting the preamble for the first time, and performs the first retransmission of the preamble. The RAR is used to indicate the uplink resource information available to the terminal device to the terminal device. The RAR at least includes: the index number of the preamble sent by the terminal device, the time adjustment information for uplink synchronization, the dedicated uplink resource position indication information allocated to the terminal device, and the temporary C-PNTI for completing conflict resolution.

[0142] In the case where the terminal device actively initiates a random access procedure to the uplink only TRP, the terminal device randomly selects a preamble with a preamble index of 15 from the preamble sequence, and selects beam 1 to transmit the preamble with a preamble index of 15 to the uplink only TRP at the transmission power P0 of the initial transmission of the preamble. Further, after the terminal device transmits the preamble with a preamble index of 15 in the initial transmission, it listens for the PDCCH in the random access response window. Correspondingly, the uplink only TRP receives but fails to successfully decode the preamble with a preamble index of 15 transmitted by the terminal device in the initial transmission, and the traditional base station does not send an RAR to the terminal device. Therefore, the terminal device does not receive the RAR sent by the traditional base station in the random access response window after transmitting the preamble with a preamble index of 15 in the initial transmission.

[0143] S403: After the terminal device transmits the preamble in the initial transmission and does not receive an RAR in the random access response window, it selects beam 2 different from the beam of the preamble in the initial transmission for the first retransmission of the preamble.

[0144] Among them, selecting beam 2 different from the beam of the preamble in the initial transmission for the first retransmission of the preamble includes: the terminal device selects beam 2 from 2 available beams to transmit the preamble to the uplink only TRP at the transmission power P0 for the first retransmission; the transmission power of the first retransmission of the preamble is still P0, so the count value of the preamble power ramping counter does not count, and the count value of the preamble power ramping counter remains 1; the count value of the preamble transmission times counter is incremented by one, and the count value of the preamble transmission times counter increases from 1 to 2.

[0145] S404: After the terminal device retransmits the preamble for the first time and does not receive an RAR in the random access response window, it selects beam 1 for the second retransmission of the preamble.

[0146] Among them, selecting beam 1 for the second retransmission of the preamble includes: as Figure 5 shown, the terminal device selects beam 1 for the second retransmission of the preamble; at this time, the terminal device has traversed the two beams of the terminal device in the first round, and the count value of the preamble power ramping counter is incremented by one, and the count value of the preamble power ramping counter increases from 1 to 2, so that the transmission power of the preamble sent by the terminal device is increased to P1, and P1 is greater than P0; the count value of the preamble transmission times counter is incremented by one, and the count value of the preamble transmission times counter increases from 2 to 3.

[0147] Optionally, after the terminal device retransmits the preamble for the first time and does not receive an RAR in the random access response window, the terminal device can refer to Figure 6, select beam 2 for the second retransmission of the preamble. For example, when the order of the terminal device's new round of traversing the terminal device beams is different from that of the first round of traversing the terminal device beams, the terminal device refers to Figure 6 , select beam 2 for the second retransmission of the preamble. Or, when the order of the terminal device's new round of traversing the terminal device beams is the same as that of the first round of traversing the terminal device beams, the terminal device does not refer to Figure 6 , select beam 2 for the second retransmission of the preamble.

[0148] S405: After the terminal device retransmits the preamble for the second time and does not receive the RAR in the random access response window, select beam 2 for the third retransmission of the preamble.

[0149] Among them, selecting beam 2 for the second retransmission of the preamble includes: as Figure 5 shown, the terminal device selects beam 2 to retransmit the preamble with transmission power P1; the count value of the preamble power climb times counter remains unchanged, and the count value of the preamble power climb times counter is still 2; the count value of the preamble transmission times counter is incremented by one, and the count value of the preamble transmission times counter increases from 3 to 4.

[0150] Optionally, after the terminal device retransmits the preamble for the second time and does not receive the RAR in the random access response window, the terminal device can refer to Figure 6 , select beam 1 to retransmit the preamble with transmission power P1. For example, when the order of the terminal device's new round of traversing the terminal device beams is different from that of the first round of traversing the terminal device beams, the terminal device selects beam 1 to retransmit the preamble with transmission power P1. Or, when the order of the terminal device's new round of traversing the terminal device beams is the same as that of the first round of traversing the terminal device beams, the terminal device does not select beam 1 to retransmit the preamble with transmission power P1.

[0151] S406: When the count value of the preamble transmission times counter reaches the maximum number of preamble transmissions, the MAC layer of the terminal device indicates to the upper layer that this random access process fails, or a random access problem.

[0152] Among them, the maximum number of preamble transmissions is an alternative description of the aforementioned preset value. The maximum number of preamble transmissions refers to the maximum threshold of the number of times the terminal device can transmit the preamble, which is a preset value configured by the network device. This preset value is the value of PREAMBLE_TRANS_MAX configured by the network device. Before the terminal device performs the random access process, it will obtain the maximum number of preamble transmissions set by the network device in advance through SIB2.

[0153] Among them, when the count value of the preamble transmission times counter reaches the maximum transmission times of the preamble, it can alternatively be described as that the count value of the preamble transmission times counter is greater than or equal to the maximum transmission times of the preamble.

[0154] S406 is an optional execution. When the maximum transmission times of the preamble configured by the network device is 4, and the terminal device does not receive the RAR in the random access response window after the third retransmission of the preamble, S406 is executed; when the maximum transmission times of the preamble configured by the network device is a natural number greater than 4, or the terminal device receives the RAR in the random access response window after the third retransmission of the preamble, S406 is not executed.

[0155] Based on Figure 4 According to the method shown above, in a communication system including a terminal device, a traditional base station, and an uplink only TRP, in the case of ideal interaction between the traditional base station and the uplink only TRP, when the terminal device does not receive the RAR in the random access response window after the initial transmission of the preamble, the terminal device selects a beam different from the beam of the initial transmission of the preamble to perform at least one retransmission of the preamble, making full use of the characteristic that the uplink path loss between the terminal device and the uplink only TRP is less than the downlink path loss between the traditional base station and the terminal device, maximizing the use of the transmission power of the terminal device for the initial transmission of the preamble, preferentially performing the retransmission of the preamble on a beam different from the beam of the initial transmission of the preamble after the initial transmission of the preamble, improving the possibility of successful random access of the terminal device, and achieving the goal of reducing the random access delay.

[0156] The above mainly introduces the solution provided by the embodiments of the present application from the perspective of the interaction between various devices. It can be understood that in order to implement the above functions, each device, such as a network device (such as a traditional base station), a terminal device, etc., includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that in combination with the algorithm steps of each example described in the embodiments disclosed in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described function for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0157] In the embodiments of the present application, functional modules of network devices, terminal devices, etc. can be grouped according to the above method examples. For example, each functional module can correspond to each functional group, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. It should be noted that the grouping of modules in the embodiments of the present application is illustrative and is only a logical functional grouping. There may be other grouping methods in actual implementation.

[0158] Figure 7 The structural diagram of a communication device 700 is shown, and the communication device 700 can be used to execute the functions of the terminal device involved in the above embodiments. As a feasible implementation method, Figure 7 The shown communication device 700 includes: a processing unit 7001 and a transceiver unit 7002;

[0159] The processing unit 7001 is used to select a beam for transmitting a preamble during a random access process; the random access process at least includes the initial transmission of the preamble, and at least one retransmission of the preamble in the case where no RAR is received in the random access response window after the initial transmission of the preamble; in the case where no RAR is received in the random access response window after the initial transmission of the preamble, select a beam different from the beam of the initial transmission of the preamble for at least one retransmission of the preamble; for example, the processing unit 7001 can support the communication device 700 to execute S401 to S403.

[0160] The transceiver unit 7002 is used to transmit the preamble; for example, the transceiver unit 7002 can be used to support the communication device 700 to execute S401 and S403.

[0161] Among them, the relevant descriptions of the random access process, the random access response window, the initial transmission of the preamble, and at least one retransmission of the preamble can be referred to the descriptions in the above method embodiments.

[0162] Specifically, Figure 4 All relevant contents of each step involved in the above Figure 4 shown method embodiments can be cited in the function descriptions of the corresponding functional modules, and will not be elaborated here. The communication device 700 is used to execute

[0163] shown functions of the terminal device in the random access process preamble transmission method, so the same effect as the above random access process preamble transmission method can be achieved. Figure 7The communication device 700 shown includes a processing module and a communication module. The processing module is used to control and manage the operations of the communication device 700. For example, the processing module may integrate the functions of the processing unit 7001 and may be used to support the communication device 700 in performing S401 to S403 and other processes of the technologies described herein. The communication module may integrate the functions of the transceiver unit 7002 and may be used to support the communication device 700 in performing S401, S403, and communication with other network entities, such as communication with Figure 4 the functional modules or network entities shown. The communication device 700 may further include a storage module for storing the program code and data of the communication device 700.

[0164] Figure 8 FIG. shows a structural diagram of a communication device 800, which may be used to perform the functions of the network device involved in the above embodiments. As an implementable manner, Figure 8 the communication device 800 shown includes a transceiver unit 8001;

[0165] The transceiver unit 8001 is used to send first indication information, and the first indication information is used to indicate the manner of sending a preamble in a random access process. For example, the transceiver unit 8001 may be used to support the communication device 800 in performing S400.

[0166] Wherein, the related descriptions of the first indication information, the random access process, and the manner of sending a preamble may be referred to those described in the above method embodiments.

[0167] Specifically, all the relevant contents of each step involved in the above Figure 4 method embodiments can be cited in the function descriptions of the corresponding functional modules and will not be elaborated herein. The communication device 800 is used to perform Figure 4 the functions of the network device in the preamble sending method of the random access process shown, and thus can achieve the same effects as the above preamble sending method of the random access process.

[0168] As another implementable manner, Figure 8 the communication device 800 shown includes a communication module and a processing module. The communication module may integrate the functions of the transceiver unit 8001 and may be used to support the communication device 800 in performing S400 and communication with other network entities, such as communication with Figure 4 the functional modules or network entities shown. The processing module is used to control and manage the operations of the communication device 800. The communication device 800 may further include a storage module for storing the program code and data of the communication device 800.

[0169] As mentioned above, the processing module may be a processor or a controller. It may implement or execute various exemplary logic blocks, modules, and circuits described in connection with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The communication module may be a transceiver circuit or a communication interface, etc. The storage module may be a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication devices 700 and 800 involved in the embodiments of the present application may be Figure 9 the communication device 900 shown. For example, the aforementioned terminal device and network device may adopt Figure 9 the composition structure shown or include Figure 9 the components shown. Figure 9 FIG. is a schematic diagram of the composition of a communication device 900 provided by an embodiment of the present application. As Figure 9 shown, the communication device 900 may include a processor 9001, a communication line 9002, and a communication interface 9003.

[0170] Furthermore, the communication device 900 may further include a memory 9004. Among them, the processor 9001, the memory 9004, and the communication interface 9003 may be connected through the communication line 9002.

[0171] Among them, the processor 9001 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 9001 may also be other communication devices with processing functions, such as circuits, devices, or software modules, etc.

[0172] The communication line 9002 is used to transmit information between the various components included in the communication device 900.

[0173] A communication interface 9003 for communicating with other devices or other communication networks. The other communication network can be an Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc. The communication interface 9003 can be a radio frequency module, a transceiver, or any communication device capable of implementing communication. In the embodiments of this application, the communication interface 9003 is taken as an example of a radio frequency module for illustration. Among them, the radio frequency module can include an antenna, a radio frequency circuit, etc., and the radio frequency circuit can include a radio frequency integrated chip, a power amplifier, etc.

[0174] A memory 9004 for storing instructions. Among them, the instructions can be computer programs.

[0175] Among them, the memory 9004 can be a read-only memory (ROM) or other types of static storage devices that can store static information and / or instructions, or a random access memory (RAM) or other types of dynamic storage devices that can store information and / or instructions. It can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, optical disc storage, magnetic disk storage media, or other magnetic storage devices. Optical disc storage includes compressed optical discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.

[0176] It should be noted that the memory 9004 can exist independently of the processor 9001 or be integrated with the processor 9001. The memory 9004 can be used to store instructions, program codes, or some data, etc. The memory 9004 can be located inside the communication device 900 or outside the communication device 900, without limitation. The processor 9001 is configured to execute the instructions stored in the memory 9004 to implement the preamble sending method for the random access process provided in the following embodiments of this application.

[0177] In one example, the processor 9001 can include one or more CPUs, such as Figure 9 CPU0 and CPU1 in

[0178] As an optional implementation manner, the communication device 900 includes multiple processors. For example, in addition to Figure 9 the processor 9001 in

[0179] As an alternative implementation, the communication device 900 further includes an output device 9005 and an input device 9006. The input device 9006 is a keyboard, a mouse, a microphone, a joystick, etc., and the output device 9005 is a display screen, a speaker, etc.

[0180] It should be noted that the communication device 900 can be a desktop computer, a laptop computer, a network server, a mobile phone, a tablet computer, a wireless terminal, an embedded device, a chip system, or a device with a Figure 9 similar structure therein. In addition, Figure 9 the component structures shown therein do not constitute a limitation on the communication device. Except Figure 9 for the components shown, the communication device may include more or fewer components than those shown, or combine certain components, or have different component arrangements.

[0181] In the embodiments of the present application, the chip system may be composed of chips or may include chips and other discrete devices.

[0182] The embodiments of the present application further provide a computer-readable storage medium. All or part of the processes in the above method embodiments may be completed by a computer program instructing relevant hardware. The program may be stored in the above computer-readable storage medium. When the program is executed, it may include the processes of the above method embodiments. The computer-readable storage medium may be the terminal device in any of the foregoing embodiments, such as an internal storage unit including a data transmission end and / or a data receiving end, for example, the hard disk or memory of the terminal device. The above computer-readable storage medium may also be an external storage device of the above terminal device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the above terminal device. Further, the above computer-readable storage medium may also include both the internal storage unit and the external storage device of the above terminal device. The above computer-readable storage medium is used to store the above computer program and other programs and data required by the above terminal device. The above computer-readable storage medium may also be used to temporarily store data that has been output or will be output.

[0183] It should be understood that in the technical solution of the present application, the processing of collection, storage, use, processing, transmission, provision, and disclosure of the user's personal information involved all comply with relevant laws and do not violate public order and good customs. For example, in the technical solution of the present application, the processing of the user's personal information is carried out under the authorization of the user. Here, the same explanation is made once, and it will not be repeated below.

[0184] It should be noted that in the description, claims and drawings of the present application, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0185] It should be understood that in the present application, "at least one (item)" means one or more, "a plurality" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or its similar expression means any combination of these items, including any combination of single item (one) or plural items (ones). For example, at least one (one) of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0186] It should be understood that in the embodiments of the present application, "B corresponding to A" means that B is associated with A. For example, B can be determined according to A. It should also be understood that determining B according to A does not mean determining B only according to A, but B can also be determined according to A and / or other information. In addition, the "connection" that appears in the embodiments of the present application refers to various connection methods such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present application do not make any limitation on this.

[0187] Unless otherwise specified, the "transmission" (transmit / transmission) that appears in the embodiments of the present application refers to two-way transmission, including the actions of sending and / or receiving. Specifically, the "transmission" in the embodiments of the present application includes the sending of data, the receiving of data, or the sending and receiving of data. Or rather, the data transmission here includes uplink and / or downlink data transmission. The data can include channels and / or signals. The uplink data transmission is the uplink channel and / or uplink signal transmission, and the downlink data transmission is the downlink channel and / or downlink signal transmission. The "network" and "system" that appear in the embodiments of the present application express the same concept, and the communication system is the communication network.

[0188] Through the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and simplicity of description, only the grouping of the above functional modules is used as an example. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0189] In several embodiments provided in the present application, it should be understood that the disclosed communication device and method can be implemented in other ways. For example, the communication device embodiments described above are merely illustrative. For example, the grouping of the modules or units is only a logical function grouping. In actual implementation, there can be other grouping methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.

[0190] The units described as separate components may or may not be physically separated. The components displayed as units can be one physical unit or multiple physical units, that is, they can be located in one place, or they can be distributed to multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0191] In addition, each functional unit in the various embodiments of the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0192] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to enable a device, such as a single-chip microcomputer, a chip, etc., or a processor to execute all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks or optical discs that store program codes.

[0193] As described above, this is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A preamble sending method for a random access procedure, characterized in that, including: selecting a beam for transmitting a preamble during a random access procedure; transmitting the preamble; the random access procedure at least includes an initial transmission of the preamble, and at least one retransmission of the preamble if a random access response RAR is not received in a random access response window after the initial transmission of the preamble; if a RAR is not received in the random access response window after the initial transmission of the preamble, selecting a beam different from the beam used for the initial transmission of the preamble for at least one retransmission of the preamble.

2. The method according to claim 1, wherein: the beams used for the first N - 1 transmissions of the preamble are not candidate beams for the Nth transmission of the preamble, where N is an integer greater than 1, N ≤ M, and M is the number of available beams.

3. The method according to any one of claims 1 - 2, wherein: if, after the Mth transmission of the preamble during the random access procedure, a RAR is still not received in the random access response window, then a (M + 1)th transmission of the preamble is performed, and the candidate beams for the (M + 1)th transmission include M beams, and the beams used for the first N - M - 1 transmissions of the preamble are not candidate beams for the Nth transmission of the preamble, where M < N ≤ 2M and M is the number of available beams.

4. The method according to any one of claims 1 - 3, wherein: the number of preamble power ramps is counted by a preamble power ramp counter; the number of preamble power ramps being counted by a preamble power ramp counter includes: if a RAR is still not received in the random access response window after the Mth integer - multiple transmission of the preamble, the count value of the preamble power ramp counter is incremented by one, where M is the number of available beams.

5. The method according to any one of claims 1 - 4, wherein: the number of preamble transmissions is counted by a preamble transmission counter; the number of preamble transmissions being counted by a preamble transmission counter includes: if a RAR is not received in the random access response window after the preamble is transmitted, the count value of the preamble transmission counter is incremented by one.

6. The method according to any one of claims 1-5, characterized in that, The method is executed by a terminal device and further includes: if the count value of the preamble transmission counter reaches a preset value, the media access control layer of the terminal device indicates a random access problem to the upper layer of the terminal device, or indicates that the random access procedure fails.

7. The method according to claim 1, characterized in that, The method further includes: receiving first indication information for indicating a manner of transmitting the preamble during the random access procedure.

8. The method according to claim 7, wherein: the manner of transmitting the preamble includes selecting a beam different from the beam used for the initial transmission of the preamble for at least one retransmission of the preamble if a RAR is not received in the random access response window after the initial transmission of the preamble.

9. The method according to claim 7, characterized in that, The receiving the first indication information includes: receiving a downlink signaling from a network device, the downlink signaling being used to trigger initiating a random access procedure to the network device, and the downlink signaling includes the first indication information.

10. The method according to claim 7 or 8, wherein the first indication information is a one-bit indication field.

11. A method for sending a preamble in a random access procedure, characterized in that, comprising: sending first indication information, the first indication information being used to indicate a manner of sending the preamble in a random access procedure.

12. The method according to claim 11, wherein the manner of sending the preamble includes selecting a beam different from the beam for initially transmitting the preamble for at least one retransmission of the preamble when a random access response (RAR) is not received in a random access response window after initially transmitting the preamble.

13. The method according to claim 11, wherein The sending of the first indication information includes: sending a downlink signaling, the downlink signaling being used to trigger initiating a random access procedure to the network device, and the downlink signaling includes the first indication information.

14. The method according to claim 11 or 13, wherein the first indication information is a one-bit indication field.

15. A communication device, characterized in that, The communication device is applied to a terminal device, and the communication device includes: a processing unit, configured to select a beam for sending a preamble in a random access procedure; a transceiver unit, configured to send the preamble; wherein the random access procedure at least includes an initial transmission of the preamble, and a retransmission of the preamble when a RAR is not received in a random access response window after initially transmitting the preamble; selecting a beam different from the beam for initially transmitting the preamble for at least one retransmission of the preamble when a RAR is not received in a random access response window after initially transmitting the preamble.

16. A communication device, characterized in that, The communication device includes a processor and a communication interface, and the processor and the communication interface are used to support the communication device to execute the method for sending a preamble in a random access procedure according to any one of claims 1-10.

17. A communication device, characterized in that, The communication device is applied to a network device, and the communication device includes: a transceiver unit, configured to send first indication information, the first indication information indicating a manner of sending a preamble in a random access procedure.

18. A communication device, characterized in that, The communication device includes a processor and a communication interface, and the processor and the communication interface are used to support the communication device to execute the method for sending a preamble in a random access procedure according to any one of claims 11-14.

19. A communication system, characterized in that, The communication system includes the communication device according to claim 15 or 16, or the communication system includes the communication device according to claim 17 or 18.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, and when the computer instructions are run on a computer, the computer is caused to execute the method according to any one of claims 1-10, or the computer is caused to execute the method according to any one of claims 11-14.

21. A computer program product, characterized in that, The computer program product includes computer instructions, and when the computer instructions are run on a computer, the computer is caused to execute the method according to any one of claims 1-10, or the computer is caused to execute the method according to any one of claims 11-14.

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