Wireless communication method and device

Abstract

Provided are a wireless communication method and apparatus, the method comprising: if a transmission parameter corresponding to a first type of PRACH transmission satisfies a condition, a terminal device performs a second type of PRACH transmission, one transmission process of the first type of PRACH transmission including one PRACH transmission, and one transmission process of the second type of PRACH transmission including multiple PRACH transmissions. In the embodiments of the present application, the terminal device can first perform the first type of PRACH transmission, and then switch to the second type of PRACH transmission when the condition is satisfied, thereby defining the combination mode of the two transmission modes. In addition, since the first type of PRACH transmission needs fewer resources, the first type of PRACH transmission is carried out firstly, so that the occupation of the resources can be reduced. After the first type of PRACH transmission meets the condition, the second type of PRACH transmission is performed, so that the coverage of the PRACH can be improved.

Description

Wireless communication method and device Technical Field

[0001] The present application relates to the field of communication technology, and more specifically, to a method and apparatus for wireless communication. Background Art

[0002] During the random access process, the terminal device needs to send a physical random access channel (PRACH) to the network device. Currently, there are two types of PRACH transmission methods, and there is no clear way to combine these two PRACH transmission methods.

[0003] Summary of the Invention

[0004] The present application provides a method and apparatus for wireless communication. The following describes various aspects of the present application.

[0005] In a first aspect, a method for wireless communication is provided, comprising: if the transmission parameters corresponding to the first type PRACH transmission meet the conditions, the terminal device performs a second type PRACH transmission, wherein one transmission process of the first type PRACH transmission includes one PRACH transmission, and one transmission process of the second type PRACH transmission includes multiple PRACH transmissions.

[0006] On the second aspect, a method is provided in which a network device receives a PRACH transmitted based on a second type of PRACH transmission method if the transmission parameters corresponding to the first type of PRACH transmission meet the conditions, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

[0007] According to a third aspect, a terminal device is provided, comprising: a transmission unit for performing a second type of PRACH transmission if the transmission parameters corresponding to the first type of physical random access channel PRACH transmission meet the conditions, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

[0008] In a fourth aspect, a network device is provided, comprising: a receiving unit, configured to receive a PRACH transmitted based on a second type of PRACH transmission mode if the transmission parameters corresponding to the first type of physical random access channel PRACH transmission meet the conditions, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

[0009] In a fifth aspect, a terminal device is provided, comprising a processor, a memory, and a communication interface, wherein the memory is used to store one or more computer programs, and the processor is used to call the computer program in the memory so that the terminal device executes part or all of the steps in the method of the first aspect.

[0010] In the sixth aspect, a network device is provided, comprising a processor, a memory, and a communication interface, wherein the memory is used to store one or more computer programs, and the processor is used to call the computer program in the memory so that the network device executes part or all of the steps in the method of the second aspect.

[0011] In a seventh aspect, an embodiment of the present application provides a communication system, which includes the above-mentioned terminal and / or network device. In another possible design, the system may also include other devices that interact with the terminal or network device in the solution provided in the embodiment of the present application.

[0012] In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program enables a terminal to execute part or all of the steps in the methods of the above aspects.

[0013] In a ninth aspect, embodiments of the present application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, wherein the computer program is operable to cause a terminal to perform some or all of the steps of the methods described in each of the above aspects. In some implementations, the computer program product may be a software installation package.

[0014] In the tenth aspect, an embodiment of the present application provides a chip, which includes a memory and a processor. The processor can call and run a computer program from the memory to implement some or all of the steps described in the methods of the above aspects.

[0015] In the embodiment of the present application, the terminal device can first perform the first type of PRACH transmission, and then switch to the second type of PRACH transmission when the conditions are met, thereby clarifying the combination of the two transmission modes. In addition, since the first type of PRACH transmission requires fewer resources, performing the first type of PRACH transmission first can reduce resource occupancy. After the first type of PRACH transmission meets the conditions, the second type of PRACH transmission can be performed, which can improve PRACH coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a wireless communication system 100 used in an embodiment of the present application.

[0017] FIG2 is a schematic flow chart of a contention-based random access method.

[0018] FIG3 is a schematic flow chart of a method for non-contention-based random access.

[0019] FIG4 is a schematic diagram of a second type of PRACH transmission provided in an embodiment of the present application.

[0020] FIG5 is a flow chart of a wireless communication method provided in an embodiment of the present application.

[0021] FIG6 is a schematic diagram of PRACH transmission based on condition 1 provided in an embodiment of the present application.

[0022] FIG7 is a schematic diagram of PRACH transmission based on condition 2 provided in an embodiment of the present application.

[0023] FIG8 is a schematic diagram of PRACH transmission based on condition 3 provided in an embodiment of the present application.

[0024] FIG9 is a schematic diagram of unified counting of two PRACH transmission types provided in an embodiment of the present application.

[0025] FIG10 is a schematic diagram of separate counting of two PRACH transmission types provided in an embodiment of the present application.

[0026] FIG11 is a schematic block diagram of a terminal device provided in an embodiment of the present application.

[0027] FIG12 is a schematic block diagram of a network device provided in an embodiment of the present application.

[0028] FIG13 is a schematic structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solution in this application will be described below with reference to the accompanying drawings.

[0030] Figure 1 illustrates a wireless communication system 100 used in an embodiment of the present application. The wireless communication system 100 may include a network device 110 and a terminal device 120. The network device 110 may be a device that communicates with the terminal device 120. The network device 110 may provide communication coverage for a specific geographic area and may communicate with the terminal device 120 within the coverage area.

[0031] FIG1 exemplarily shows a network device and two terminals. Optionally, the wireless communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0032] Optionally, the wireless communication system 100 may further include other network entities such as a network controller and a mobility management entity, which is not limited in the embodiment of the present application.

[0033] It should be understood that the technical solutions of the embodiments of the present application can be applied to various communication systems, such as: fifth generation (5G) system or new radio (NR), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), etc. The technical solutions provided in this application can also be applied to future communication systems, such as the sixth generation mobile communication system, satellite communication system, etc.

[0034] The terminal device in the embodiments of the present application may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiments of the present application may refer to a device that provides voice and / or data connectivity to a user and can be used to connect people, objects and machines, such as a handheld device with wireless connection function, a vehicle-mounted device, etc. The terminal device in the embodiments of the present application can be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. Optionally, the UE can be used to act as a base station. For example, the UE can act as a scheduling entity that provides sidelink signals between UEs in V2X or D2D, etc. For example, a cellular phone and a car communicate with each other using sidelink signals. The cellular phone and smart home devices communicate without relaying the communication signal through the base station.

[0035] The network device in the embodiments of the present application may be a device for communicating with a terminal device, and may also be referred to as an access network device or a radio access network device. For example, the network device may be a base station. The network device in the embodiments of the present application may refer to a radio access network (RAN) node (or device) that connects a terminal device to a wireless network. A base station can broadly cover various names as follows, or be replaced with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (TRP), transmission point (TP), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. A base station can also refer to a communication module, a modem or a chip used to be set in the aforementioned device or apparatus. The base station can also be a mobile switching center and a device that performs base station functions in device-to-device D2D, vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. The base station can support networks with the same or different access technologies. The embodiments of this application do not limit the specific technology and specific device form used by the network equipment.

[0036] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

[0037] In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device may include a CU and a DU. The gNB may also include an AAU.

[0038] The network equipment and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; they can also be deployed in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the scenarios in which the network equipment and terminal devices are located.

[0039] It should be understood that all or part of the functions of the communication device in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (such as a cloud platform).

[0040] Terminal devices can achieve uplink synchronization through random access. There are two types of random access: contention-based random access and non-contention-based random access. These two random access methods are described below with reference to Figures 2 and 3.

[0041] FIG2 is a flowchart of a contention-based random access method provided in an embodiment of the present application, which includes steps S210 to S240.

[0042] In step S210, the terminal device sends a message 1 (message 1, Msg1) in a random access process to the network device, where the message 1 includes a preamble.

[0043] The terminal device can select a PRACH resource and a preamble, and send the selected preamble on the selected resource. The PRACH resource may also be referred to as a RACH resource.

[0044] The network device may send the configuration information of the PRACH resource to the terminal device in the form of broadcast. The configuration information of the PRACH resource may be used to determine the time domain information, frequency domain information and code domain information of the PRACH resource.

[0045] The configuration information of the PRACH resource includes one or more of the following information: preamble format, PRACH resource repetition period, radio frame offset, subframe number within a radio frame, starting symbol within a subframe, number of PRACH slots within a subframe, number of PRACH occasions (RO) within a PRACH slot, and duration of a PRACH occasion. Based on the configuration information of the PRACH resource, the terminal device can determine the time domain information, frequency domain information, and code domain information of the PRACH resource.

[0046] The configuration information of the PRACH resources can be carried in the system message, that is, the network device can send the configuration information of the RACH through the system message. In addition, the system message can also indicate the association relationship between the synchronization signal block (SSB) and the PRACH resource. The terminal device can determine the PRACH resources that can be used, such as the PRACH timing and the preamble code based on the detected SSB and the association relationship. In some embodiments, the network device can control the terminal device's selection of random access resources by configuring a reference signal receiving power (RSRP) threshold. The terminal device can select an SSB whose RSRP measurement value meets the RSRP threshold based on the measurement result of the SSB, and use the PRACH resource associated with the SSB to send the preamble code.

[0047] In step S220, the network device sends Msg2 to the terminal device. The Msg2 may also be called a random access response (RAR). The Msg2 may be carried by a physical downlink control channel (PDCCH).

[0048] After the terminal device sends Msg1, it can open a RAR time window and listen for the PDCCH scrambled by the random access radio network temporary identifier (RA-RNTI) within the RAR time window. The RA-RNTI is related to the time-frequency resources of the RACH used by the terminal device to send Msg1. After the terminal device receives the PDCCH, it can use the RA-RNTI to decode the PDCCH.

[0049] Msg2 may also include a preamble sent by the terminal device. If the terminal device receives a PDCCH scrambled with RA-RNTI and Msg2 contains the preamble sent by itself, the terminal device may consider that the random access response has been successfully received.

[0050] After the terminal device successfully receives the PDCCH, the terminal device can obtain the physical downlink shared channel (PDSCH) scheduled by the PDCCH, wherein the PDSCH contains the RAR. The RAR can contain multiple information. For example, the subheader of the RAR can contain a backoff indicator (BI), which can be used to indicate the backoff time for retransmitting Msg1; the random access preamble identification (RAPID) in the RAR indicates the preamble index to which the network device responds to the received data; the payload in the RAR can contain a timing advance group (TAG), which can be used to adjust the uplink timing; the RAR can also include an uplink grant (UL grant) for scheduling the uplink resource indication of Msg3; the RAR can also include a temporary cell-radio network temporary identifier (C-RNTI). For a terminal device that is initially accessing, the terminal device can use the temporary C-RNTI to decode the PDCCH of Msg4.

[0051] Step S230: The terminal device sends Msg3 to the network device. The terminal device may send Msg3 on the uplink grant scheduled by the network device. The Msg3 may also be called a Radio Resource Control (RRC) connection establishment request message.

[0052] The Msg3 is mainly used to inform the network device of the event that triggered the random access process. For example, if it is an initial random access process, the terminal device can carry the UE identity (ID) and establishment cause in the Msg3. If it is an RRC reestablishment, the terminal device can carry the connected UE identity and establishment cause in the Msg3.

[0053] Step S240: The network device sends Msg4 to the terminal device. Msg4 may also be called a conflict resolution message.

[0054] The Msg4 has two functions, one is for contention conflict resolution, and the other is to send an RRC configuration message to the terminal device. If the terminal device carries C-RNTI in Msg3, Msg4 is scheduled using the PDCCH scrambled by the C-RNTI. Accordingly, the terminal device can use the C-RNTI in Msg3 to decode the PDCCH to obtain Msg4. If the terminal device does not carry C-RNTI in Msg3, such as initial access, Msg4 can be scheduled using the PDCCH scrambled by the temporary C-RNTI. Accordingly, the terminal device can use the temporary C-RNTI in Msg2 to decode the PDCCH to obtain Msg4. After successfully decoding the PDCCH, the terminal device obtains the PDSCH carrying Msg4. The terminal device can compare the common control channel (CCCH) service data unit (SDU) in the PDSCH with the CCCH SDU in Msg3. If the two are the same, it means that the contention resolution is successful.

[0055] FIG3 is a flow chart of a non-contention-based random access method provided by an embodiment of the present application. The method includes steps S310 to S330.

[0056] In step S310, the network device sends preamble configuration information to the terminal device, where the configuration information includes the preamble and RACH resources required in the random access process.

[0057] In step S320, the terminal device may send Msg1 to the network device according to the preamble configuration information, that is, the terminal device may send the preamble to the network device on the RACH resource.

[0058] In step S330, the network device sends Msg2 to the terminal device, and the Msg2 may include RAR. After the terminal device receives the RAR, it indicates that the random access process is completed.

[0059] After each preamble transmission, the terminal device checks for the RAR within the RAR window. If the RAR sent by the network device is not received within the RAR window, or if the terminal device does not receive Msg4, the terminal device needs to retransmit the PRACH. This means that the terminal device can retransmit the preamble on the next available PRACH resource. This process is also called PRACH retransmission. The following describes PRACH retransmission using the example of a terminal device not receiving the RAR sent by the network device.

[0060] It should be noted that the random access process of the terminal device may include multiple PRACH transmissions. In the embodiment of the present application, the first PRACH transmission in the random access process may be referred to as the initial transmission of PRACH, and the subsequent PRACH transmissions may be referred to as PRACH retransmissions.

[0061] To improve PRACH coverage, the power of the preamble transmitted by the terminal device increases by one step based on the previous transmit power. For terminal devices that support multiple transmit beams, if the transmit beam remains unchanged, the transmit power of the retransmitted PRACH also increases based on the previous PRACH power. This method of determining transmit power prevents the terminal device from transmitting with more power than necessary, thereby reducing interference caused by the terminal device's PRACH transmission.

[0062] The following describes how to calculate the transmission power of the preamble.

[0063] PRACH power control uses an open-loop power control mechanism. The terminal device can determine the PRACH transmit power based on factors such as the expected receive power configured by the network equipment and path loss.

[0064] PRACH transmission power P PRACH,b,f,c (i) can be determined by the following formula (1):

[0065] P PRACH,b,f,c (i) = min{P CMAX,f,c (i),P PRACH,target,f,c +PL b,f,c} (Formula 1)

[0066] Among them, P CMAX,f,c (i) represents the maximum transmit power of the terminal device corresponding to transmission opportunity i in the serving cell c on carrier f, PL b,f,c represents the measured path loss, P PRACH,target,f,c Indicates the target received power of PRACH determined by the media access control (MAC) layer. The path loss can be the path loss measured by the terminal device on carrier f for the activated UL bandwidth part (BWP) b based on the downlink (DL) reference signal (RS) associated with the PRACH transmission in the activated downlink BWP of the serving cell c. P PRACH,target,f,c +PL b,f,c In the following, it is also referred to as the power calculated by the open-loop power control.

[0067] PREAMBLE_RECEIVED_TARGET_POWER can be determined based on the following formula (2):

[0068] PREAMBLE_RECEIVED_TARGET_POWER=preambleReceivedTargetPower+DELTA_PREAMBLE+(PREAMBLE_POWER_RAMPING_COUNTER–1)×PREAMBLE_POWER_RAMPING_STEP+POWER_OFFSET_2STEP_RA(Formula 2)

[0069] preambleReceivedTargetPower indicates the target receive power of the PRACH configured by the higher layer, DELTA_PREAMBLE indicates the compensation value, PREAMBLE_POWER_RAMPING_COUNTER indicates the number of PRACH transmissions, PREAMBLE_POWER_RAMPING_STEP indicates the power ramp step, and POWER_OFFSET_2STEP_RA indicates the offset value.

[0070] After the terminal device transmits a PRACH to the network device, it detects the RAR sent by the network device within the RAR window. If the RAR sent by the network device is not received, the terminal device retransmits the PRACH. The power of the retransmitted RAR by the terminal device can be increased according to formula (1), and the terminal device can use the increased power to retransmit the PRACH.

[0071] For the convenience of description, the above PRACH transmission mode is referred to as the first type of PRACH transmission below. From the above formula (1), it can be seen that the maximum transmission power of the first type of PRACH transmission is P CMAX,f,c (i) That is, the PRACH transmit power cannot be increased indefinitely. When PRACH coverage is limited, a terminal device cannot increase its PRACH transmit power indefinitely to allow network equipment to detect it. To improve PRACH coverage, the protocol introduces a second type of PRACH transmission, also known as PRACH repetition.

[0072] Referring to Figure 4 , the second type of PRACH transmission can be understood as a terminal device performing multiple PRACH transmissions in a single transmission process, each corresponding to a single RAR window. Figure 4 illustrates a single transmission process that includes four PRACH transmissions. Network devices can combine and receive multiple PRACHs to improve detection performance, thereby increasing PRACH coverage.

[0073] As described above, the prior art includes two PRACH transmission modes: Type I PRACH transmission and Type II PRACH transmission. Both transmission modes can improve PRACH coverage. However, there is currently no clear definition of how to combine these two transmission modes to improve PRACH coverage.

[0074] Based on this, an embodiment of the present application provides a method for wireless communication, which clarifies the combination of two transmission modes. The PRACH transmission in the embodiment of the present application includes two types, namely, first-type PRACH transmission and second-type PRACH transmission, and the first-type PRACH transmission and the second-type PRACH transmission have different transmission modes. For ease of understanding, these two types of PRACH transmission are first introduced.

[0075] The first type of PRACH transmission can be the PRACH retransmission method introduced above. The first type of PRACH transmission can be understood as a PRACH transmission performed using the first transmission mode. The first PRACH transmission can also be referred to as a single transmission or a separate transmission or a PRACH retransmission (re-transmission). In some embodiments, a transmission process of the first type of PRACH transmission includes one PRACH transmission (or one PRACH). A transmission process can be understood as a process of performing PRACH transmission between two RAR windows. In some embodiments, one PRACH transmission in the first type of PRACH transmission corresponds to one RAR window. In other words, in the first type of PRACH transmission, one RAR window corresponds to one PRACH transmission, or one RAR window is associated with one PRACH transmission.

[0076] In some embodiments, during the process of performing the first type of PRACH transmission, the terminal device may send a PRACH to the network device, and then detect the RAR sent by the network device in the RAR window. If the RAR sent by the network device is not detected, the terminal device may send another PRACH on the next available PRACH resource, and then detect the RAR on the RAR window corresponding to the PRACH, and so on. As can be seen from the above, during the process of performing the first type of PRACH transmission, each PRACH can correspond to an independent RAR window, that is, each PRACH transmission is detected on the corresponding RAR window.

[0077] The second type of PRACH transmission can be understood as a PRACH transmission performed using a second transmission mode. The second transmission mode is different from the first transmission mode. The second type of PRACH transmission can also be referred to as a repetition of PRACH. In some embodiments, a transmission process of the second type of PRACH transmission may include multiple PRACH transmissions. A transmission process can be understood as a process of performing PRACH transmission between two RAR windows. In some embodiments, multiple PRACH transmissions in the second type of PRACH transmission correspond to one RAR window. In other words, in the second type of PRACH transmission, one RAR window corresponds to multiple PRACH transmissions, or one RAR window is associated with multiple PRACH transmissions. It should be noted that in the embodiment of the present application, the multiple PRACH transmissions are recorded as a whole as one transmission.

[0078] In some embodiments, during the second type PRACH transmission process, the terminal device may send multiple PRACHs to the network device, and then detect the RAR sent by the network device in the RAR window. If the RAR sent by the network device is not detected, the terminal device may send multiple PRACHs again on the next available PRACH resource, and then detect the RAR on the RAR window corresponding to the multiple PRACHs, and so on. As can be seen from the above, during the second type PRACH transmission process, multiple PRACHs are mutually associated or bound, and the multiple PRACHs correspond to one RAR window.

[0079] The embodiments of the present application do not limit the number of PRACHs included in a single transmission of the second type of PRACH transmission. For example, the number of PRACHs included in a single transmission can be any integer greater than 1, such as 2, 3, 4, etc. It is understood that the greater the number of PRACHs included in a single transmission, the better the PRACH coverage performance.

[0080] The number of PRACHs included in one transmission process may be predefined in the protocol or indicated by the network device, and this embodiment of the present application does not specifically limit this.

[0081] In some embodiments, the network device may send a RAR to the terminal device after the transmission of multiple PRACHs in one transmission process is completed, or may send a RAR to the terminal device after receiving part of the PRACHs among multiple PRACHs. For example, a PRACH transmission process may include 4 PRACH transmissions, and the network device may send a RAR to the terminal device after receiving one PRACH transmission, 2 PRACH transmissions, or 3 PRACH transmissions of the 4 PRACH transmissions. For example, if the network device is able to completely parse the PRACH information after receiving the first PRACH, the network device may not receive other PRACHs, and may directly send a RAR to the terminal device after receiving the first PRACH.

[0082] The solution of the embodiment of the present application is described in detail below with reference to FIG5 .

[0083] Referring to Figure 5, in step S510, if the transmission parameters corresponding to the first type PRACH transmission meet the conditions, the terminal device can perform the second type PRACH transmission. That is, if the transmission parameters corresponding to the first type PRACH transmission meet the conditions, the terminal device can send a PRACH transmitted based on the second type PRACH transmission mode to the network device, that is, the network device can receive the PRACH transmitted based on the second type PRACH transmission mode sent by the terminal device.

[0084] In an embodiment of the present application, the terminal device may first perform a first type of PRACH transmission, and then switch to a second type of PRACH transmission when conditions are met. Since the first type of PRACH transmission requires fewer resources, performing the first type of PRACH transmission first can reduce resource usage. After the first type of PRACH transmission meets the conditions, the second type of PRACH transmission is performed to improve PRACH coverage.

[0085] In some embodiments, the transmission parameter may include any parameter related to PRACH transmission. For example, the transmission parameter may include one or more of the following: transmit power, number of transmissions, and downlink path loss. In other words, the condition may be associated with one or more of the following information: transmit power corresponding to the first type of PRACH transmission, number of transmissions corresponding to the first type of PRACH transmission, and downlink path loss.

[0086] The higher the PRACH transmit power, the worse the coverage at the terminal device's location, and a higher transmit power is required to meet the target transmit power. Therefore, based on the transmit power determination conditions, the terminal device can perform a second type of PRACH transmission at a higher transmit power to improve PRACH coverage.

[0087] As can be seen from formula (1), the more PRACH transmissions there are, the greater the transmit power of the terminal device is, and the worse the coverage at the terminal device's location is. Therefore, by determining the condition based on the number of transmissions, the terminal device can perform the second type of PRACH transmission when the number of transmissions is high, thereby improving PRACH coverage.

[0088] If the downlink path loss measured by the terminal device is large, it indicates that the coverage at the terminal device's location is poor. Therefore, based on the downlink path loss determination condition, the terminal device can perform the second type of PRACH transmission in the case of poor coverage to improve PRACH coverage.

[0089] The embodiments of the present application do not specifically limit the conditions. As an example, the condition may include that the transmit power corresponding to the first-type PRACH transmission reaches the maximum transmit power of the terminal device. As another example, the condition may include that the transmit power corresponding to the first-type PRACH transmission is greater than or equal to a first threshold. As yet another example, the condition may include that the number of transmissions corresponding to the first-type PRACH transmission is greater than or equal to a second threshold.

[0090] It should be noted that the embodiment of the present application may perform the second type of PRACH transmission this time when the conditions are met, or may perform the second type of PRACH transmission the next time when the conditions are met. For example, the terminal device may still perform the first type of PRACH transmission this time when the conditions are met, and switch to the second type of PRACH transmission the next time when the conditions are met.

[0091] The following is an introduction to the above three conditions respectively.

[0092] Condition 1: The transmit power corresponding to the first type of PRACH transmission reaches the maximum transmit power of the terminal device

[0093] As described above, the PRACH transmit power can be determined based on the target receive power, path loss, PRACH power ramp times, and step size configured by the higher layer. For terminal devices, open-loop power control can be used to determine the initial PRACH power, followed by a gradual power ramp, ultimately enabling network devices to successfully detect the PRACH (or preamble) sent by the terminal device. This approach has the advantage of avoiding transmitting with more power than necessary, thereby reducing interference caused by the terminal device.

[0094] For terminal devices with poor coverage, the calculated path loss will be relatively large, and the power calculated by open-loop power control may reach or exceed the maximum transmit power of the terminal device. This situation may occur during the initial transmission of PRACH, or it may occur during the retransmission process of the terminal device. For example, during the initial transmission of PRACH, the open-loop power calculated by the terminal device reaches or exceeds the maximum transmit power. For another example, during the initial transmission of PRACH, the open-loop power calculated by the terminal device does not reach or exceed the maximum transmit power, but in the subsequent retransmission process, since the terminal device will perform power climbing, the power after climbing may reach or exceed the maximum transmit power.

[0095] According to formula (1), if the power determined by open-loop power control reaches or exceeds the maximum transmit power, the terminal device will use the maximum transmit power as the PRACH transmit power. The power of subsequent PRACH retransmissions will no longer be able to increase and will only be transmitted at the maximum transmit power. In this case, the terminal device will not be able to improve PRACH coverage by increasing the PRACH transmit power.

[0096] In an embodiment of the present application, the terminal device can perform second-type PRACH transmission after the transmission power corresponding to the first-type PRACH transmission reaches the maximum transmission power, so that the PRACH coverage can be further improved.

[0097] In some embodiments, before each PRACH transmission, the terminal device may calculate the required power using the first type PRACH transmission (i.e., formula (1)) and compare the power with the maximum transmit power. If the power is less than the maximum transmit power, the first type PRACH transmission is performed. If the power is equal to the maximum transmit power, the second type PRACH transmission is performed.

[0098] The following describes the PRACH transmission process in conjunction with FIG6 .

[0099] When the terminal device performs the first PRACH transmission, it can first calculate the required transmission power according to formula (1). Since the calculated transmission power is less than the maximum transmission power, the terminal device performs the first type of PRACH transmission. If the terminal device does not detect the RAR sent by the network device in the RAR window corresponding to the first PRACH transmission, the terminal device performs the second PRACH transmission. The terminal device recalculates the transmission power according to formula (1), that is, increases the transmission power of PRACH. Since the calculated transmission power is less than the maximum transmission power, the terminal device performs the first type of PRACH transmission. If the terminal device does not detect the RAR sent by the network device in the RAR window corresponding to the second PRACH transmission, the terminal device performs the third PRACH transmission. The terminal device recalculates the transmission power according to formula (1), that is, increases the transmission power of PRACH. Since the third calculated transmission power is equal to the maximum transmission power, it meets the conditions for performing the second type of PRACH transmission, and the terminal device performs the second type of PRACH transmission. The terminal device can send multiple PRACHs during the third PRACH transmission. As shown in Figure 6, the terminal device can send four PRACHs during the third PRACH transmission process. The four PRACHs correspond to one RAR window, and the terminal device can detect the RAR sent by the network device in the RAR window.

[0100] Condition 2: The transmit power corresponding to the first type of PRACH transmission is greater than or equal to the first threshold

[0101] In some embodiments, condition 2 may also be that the transmit power corresponding to the first type PRACH transmission reaches or satisfies the first threshold.

[0102] In this embodiment, if the power calculated by open-loop power control is less than the maximum transmit power, the PRACH transmit power is equal to the power calculated by open-loop power control. The following text primarily uses the term "power calculated by open-loop power control" to describe the solution of this embodiment.

[0103] As can be seen from the previous method of calculating power through open-loop power control, the PRACH power takes into account the downlink path loss, which also reflects the current coverage level of the terminal device. Therefore, when it is necessary to determine whether to perform the second type of PRACH transmission, the path loss (the measurement result of the downlink signal) can be used as a consideration. For example, the path loss obtained by measuring the downlink reference signal and / or the PRACH power calculated based on the path loss can be used as a judgment condition for whether to perform the second type of PRACH transmission.

[0104] The terminal device can obtain the transmit power according to the open-loop power control calculation. If the transmit power is less than the maximum transmit power, the PRACH is transmitted using the transmit power. In an embodiment of the present application, the greater the transmit power of the PRACH obtained by the open-loop power control calculation, the worse the coverage of the terminal device's location, and the terminal device needs to transmit the PRACH with a higher power to meet the target receive power requirement. Therefore, an embodiment of the present application can set a threshold for the PRACH transmit power (denoted as the first threshold). If the calculated transmit power is greater than or equal to the first threshold, or if the calculated transmit power reaches or meets the first threshold, the terminal device can perform a second type of PRACH transmission. By setting a reasonable first threshold, the waste of terminal device power and the interference caused by the terminal device can be reduced.

[0105] In some embodiments, the first threshold is less than the maximum transmit power. In some embodiments, the first threshold can be determined based on the maximum transmit power. For example, the first threshold can be reduced by an offset value based on the maximum transmit power. The embodiment of the present application does not specifically limit the size of the offset value. For example, the offset value can be a value in the range of 1 to 3 dB. The terminal device can determine the first threshold based on the offset value and the maximum transmit power. In other embodiments, the first threshold can be a specific value in dBm. For ease of description, the first threshold and / or offset value will be referred to as the configuration information of the first threshold below.

[0106] The configuration information of the first threshold may be predefined in a protocol, or may be indicated by a network device to a terminal device. For example, the network device may indicate the configuration information of the first threshold in a system message.

[0107] In some embodiments, the configuration of the configuration information of the first threshold is optional. For example, the network device may configure the configuration information of the first threshold for the terminal device, or may not configure the configuration information of the first threshold for the terminal device. If the network device is configured with the configuration information of the first threshold, the terminal device may determine whether to perform the second type of PRACH transmission based on the first threshold. If the network device does not configure the configuration information of the first threshold for the terminal device, the terminal device may not determine whether to perform the second type of PRACH transmission based on the first threshold. In this case, the terminal device may not perform the second type of PRACH transmission, or the terminal device may determine whether to perform PRACH transmission based on other conditions. For example, the terminal device may determine whether to perform the second type of PRACH transmission based on the maximum transmit power (such as condition 1 described above), or the terminal device may determine whether to perform the second type of PRACH transmission based on the number of transmissions (such as condition 3 described below).

[0108] In some embodiments, each time a PRACH transmission is performed, the terminal device may first calculate the required power using a first type of PRACH transmission and compare the power with a first threshold. If the power is less than the first threshold, the first type of PRACH transmission is performed. If the power is greater than or equal to the first threshold, the second type of PRACH transmission is performed.

[0109] The following describes the PRACH transmission process in conjunction with FIG7 .

[0110] When the terminal device performs the first PRACH transmission, it can first calculate the required transmission power according to formula (1). Since the transmission power is less than the first threshold, the terminal device performs the first type of PRACH transmission. If the terminal device does not detect the RAR sent by the network device in the RAR window corresponding to the first PRACH transmission, the terminal device performs the second PRACH transmission. The terminal device recalculates the transmission power according to formula (1), that is, increases the transmission power of PRACH. Since the calculated transmission power is less than the first threshold, the terminal device performs the first type of PRACH transmission. If the terminal device does not detect the RAR sent by the network device in the RAR window corresponding to the second PRACH transmission, the terminal device performs the third PRACH transmission. The terminal device recalculates the transmission power according to formula (1), that is, increases the transmission power of PRACH. Since the third calculated transmission power is greater than or equal to the first threshold and meets the conditions for the second type of PRACH transmission, the terminal device performs the second type of PRACH transmission. The terminal device can send multiple PRACHs during the third PRACH transmission. As shown in Figure 7, the terminal device can send four PRACHs during the third PRACH transmission process. The four PRACHs correspond to a RAR window, and the terminal device can detect the RAR sent by the network device in the RAR window.

[0111] Condition 3: The number of transmissions corresponding to the first type of PRACH transmission is greater than or equal to the second threshold

[0112] In some embodiments, condition 3 may also be that the number of transmissions corresponding to the first type PRACH transmission reaches or satisfies the second threshold. For example, condition 3 may be that the number of transmissions corresponding to the first type PRACH transmission equals the second threshold.

[0113] As described above, the PRACH transmit power can be determined based on the target receive power configured by the higher layer, path loss, the number of PRACH power ramps, and the step size. The PREAMBLE_POWER_RAMPING_COUNTER is used to count the number of PRACH transmissions, thereby determining the number of PRACH power ramp steps. Therefore, the more PRACH transmissions, the higher the PRACH power transmitted by the terminal device, and the worse the coverage at the location.

[0114] In some embodiments, whether to perform second-type PRACH transmission can be determined based on the number of PRACH transmissions. For example, if the number of PRACH transmissions is greater than or equal to the second threshold, or if the number of PRACH transmissions reaches or meets the second threshold, the terminal device can perform second-type PRACH transmission. By setting a reasonable second threshold, the embodiments of the present application can reduce terminal device power waste and interference caused by the terminal device.

[0115] In some embodiments, the second threshold may be predefined in a protocol, or may be indicated by the network device to the terminal device. For example, the network device may indicate the second threshold in a system message.

[0116] In some embodiments, the configuration of the second threshold is optional. For example, the network device may configure the second threshold for the terminal device, or may not configure the second threshold for the terminal device. If the network device is configured with the second threshold, the terminal device may determine whether to perform the second type of PRACH transmission based on the second threshold. If the network device does not configure the second threshold for the terminal device, the terminal device may not determine whether to perform the second type of PRACH transmission based on the second threshold. In some embodiments, if the network device does not configure the second threshold for the terminal device, the terminal device may not perform the second type of PRACH transmission, or the terminal device may determine whether to perform PRACH transmission based on other conditions. For example, the terminal device may determine whether to perform the second type of PRACH transmission based on the maximum transmit power (such as condition 1 described above), or the terminal device may determine whether to perform the second type of PRACH transmission based on the first threshold (such as condition 2 described above).

[0117] In some embodiments, the terminal device may compare the number of transmissions with the second threshold each time a PRACH transmission is performed. If the number of transmissions is less than the second threshold, a first type of PRACH transmission is performed. If the number of transmissions is greater than or equal to the second threshold, or the number of transmissions reaches or satisfies the second threshold, a second type of PRACH transmission is performed. If the number of transmissions is greater than or equal to the second threshold, the terminal device may perform a second type of PRACH transmission during this or the next PRACH transmission. For example, if the value of the second threshold is 2, the terminal device may perform a second type of PRACH transmission during the second PRACH transmission. Alternatively, the terminal device may still perform the first type of PRACH transmission during the second PRACH transmission, but perform the second type of PRACH transmission during the third PRACH transmission.

[0118] 8 , the PRACH transmission process will be described below by taking the next second type PRACH transmission when condition 3 is satisfied as an example.

[0119] Assuming the value of the second threshold is 2, the terminal device can perform the first type of PRACH transmission during the first two PRACH transmissions and the second type of PRACH transmission during the third PRACH transmission. The terminal device can send multiple PRACHs during the third PRACH transmission. As shown in Figure 8, the terminal device can send four PRACHs during the third PRACH transmission. These four PRACHs correspond to an RAR window, and the terminal device can detect the RAR sent by the network device in this RAR window.

[0120] The multiple conditions described above can be used alone or in combination with each other, and the embodiments of the present application do not specifically limit this. As an example, condition 1, condition 2, and condition 3 can be used alone, and the terminal device can determine whether to perform a second type of PRACH transmission based on any one of condition 1, condition 2, and condition 3. As another example, condition 1, condition 2, and condition 3 can be used in combination with each other. For example, condition 1 and condition 3 can be combined with each other, and condition 2 and condition 3 can be combined with each other. If condition 1 and condition 3 are combined with each other, the terminal device can perform a second type of PRACH transmission when condition 1 and condition 3 are simultaneously met, or the terminal device can also perform a second type of PRACH transmission when any one of condition 1 and condition 3 is met. If condition 2 and condition 3 are combined with each other, the terminal device can perform a second type of PRACH transmission when condition 2 and condition 3 are simultaneously met, or the terminal device can also perform a second type of PRACH transmission when any one of condition 2 and condition 3 is met.

[0121] The embodiments of the present application are mainly concerned with the conditions for switching from the first type PRACH transmission to the second type PRACH transmission. As for how to perform the second type PRACH transmission after switching to the second type PRACH transmission, the number of transmissions of the second type PRACH transmission, or whether it is necessary to switch to the first type PRACH transmission again, the embodiments of the present application do not make specific restrictions.

[0122] As an example, after switching to the second type PRACH transmission, the terminal device may continue to perform the second type PRACH transmission until random access fails (i.e., the number of transmissions reaches the maximum number of transmissions and the RAR sent by the network device is not received), or random access succeeds.

[0123] As another example, after switching to the second type PRACH transmission, the terminal device may perform a preset number of second type PRACH transmissions. When the number of second type PRACH transmissions reaches the preset number, the terminal device may switch to the first type PRACH transmission.

[0124] As another example, after switching to the second type of PRACH transmission, the terminal device may switch to the first type of PRACH transmission after the transmit power of the PRACH reaches the target transmit power.

[0125] The embodiments of the present application do not specifically limit the transmission conditions for initiating the first type of PRACH transmission. For example, the terminal device may directly use the first type of PRACH transmission during the initial transmission of the PRACH. For another example, the terminal device may first determine whether the initial conditions for directly performing the second type of PRACH transmission are met. If the initial conditions are not met, the terminal device may first perform the first type of PRACH transmission. It should be noted that this initial condition is different from the conditions described above.

[0126] The above describes the conditions for switching from the first type PRACH transmission to the second type PRACH transmission. The following describes the transmit power corresponding to the second type PRACH transmission.

[0127] The transmit power corresponding to the second type PRACH transmission can be understood as the transmit power used for the second type PRACH transmission. For the convenience of description, the transmit power corresponding to the second type PRACH transmission is referred to as the second power below.

[0128] A transmission process of the second type of PRACH transmission includes multiple PRACH transmissions, and the second power can be the transmission power of any one of the multiple PRACH transmissions (such as the transmission power of any one of PRACH 1 to PRACH 4 in Figures 6 to 8). For example, the second power can be the transmission power of the PRACH with the earliest transmission time among the multiple PRACH transmissions (such as the transmission power of PRACH 1 in Figures 6 to 8), and the transmission power of the PRACH with the earliest transmission time can be understood as the first PRACH transmission among the multiple PRACH transmissions. Of course, the second power can also be the transmission power of other PRACHs in the multiple PRACH transmissions, such as the transmission power of the PRACH with the latest transmission time (such as the transmission power of PRACH 4 in Figures 6 to 8).

[0129] The transmit powers of the multiple PRACH transmissions may be equal or unequal. The unequal transmit powers of the multiple PRACH transmissions may include any two transmit powers of the multiple PRACH transmissions being unequal, or some transmit powers of the multiple PRACH transmissions being unequal.

[0130] If the transmit powers of the multiple PRACH transmissions are equal, the transmit powers of the multiple PRACH transmissions may all be the second power. For another example, if the transmit powers of the multiple PRACH transmissions are not equal, the second power may be the transmit power of a certain PRACH transmission among the multiple PRACH transmissions. The transmit powers of other PRACH transmissions among the multiple PRACH transmissions may be determined based on the second power. Taking the second power as the transmit power of the first PRACH transmission among the multiple PRACH transmissions as an example, the transmit powers of other PRACH transmissions may be increased on the basis of the second power. Taking Figures 6 to 8 as an example, the second power is the transmit power of PRACH 1. The transmit power of PRACH 2 may be the power after it is increased based on the second power (denoted as power a). The transmit power of PRACH 3 may be the power after it is increased based on power a (denoted as power b). The transmit power of PRACH may be the power after it is increased based on power b. The step size of the increase may be the same as or different from the traditional method, and the embodiments of the present application do not specifically limit this.

[0131] The second power may be determined based on the first power, the first power may be determined based on the transmit power corresponding to the first type of PRACH transmission, or the first power may be determined based on the maximum transmit power of the terminal device.

[0132] The transmit power corresponding to the first type PRACH transmission may refer to the transmit power corresponding to any one PRACH transmission of the first type PRACH transmission.

[0133] In some embodiments, the first power may be determined based on the transmit power corresponding to the last transmission in the first type of PRACH transmission. For ease of description, the transmit power corresponding to the last transmission in the first type of PRACH transmission is referred to as the last transmit power, and the last transmission in the first type of PRACH transmission is referred to as the last transmission. For example, the first power may be equal to the last transmit power. Taking Figures 6 to 8 as an example, the last transmit power is the power used for the second PRACH transmission. It is understandable that in the next transmission after the last transmission, the terminal device performs a second type of PRACH transmission.

[0134] In some embodiments, the first power may be greater than the last transmission power, thereby enabling the terminal device to perform the second type of PRACH transmission at a higher power to further improve the coverage of the PRACH.

[0135] In some embodiments, the first power may be determined based on the transmit power corresponding to the first PRACH transmission when the condition is met. In other words, the first power may be determined based on the transmit power corresponding to the N+1th transmission of the PRACH, where N represents the total number of transmissions corresponding to the first type of PRACH transmission. The Nth transmission may be understood as the last transmission in the first type of PRACH transmission. In other words, the first power may be determined based on the transmit power corresponding to the first type of PRACH transmission next to the last transmission. For example, the first power may be equal to the transmit power corresponding to the N+1th transmission. The following example illustrates the method for determining the first power in combination with the above conditions 1 to 3.

[0136] For condition 1, see Figure 6. During the third PRACH transmission, the terminal device first calculates the power corresponding to the first type of PRACH transmission. Since this power is equal to the maximum transmit power P CMAX,f,c (i), the terminal device can perform the second type PRACH transmission. In the embodiment of the present application, the first power can be based on the maximum transmit power P CMAX,f,c (i) Determine that the second power of the second type PRACH transmission can be based on the maximum transmit power P CMAX，,f,c (i) Determination.

[0137] For condition 2, referring to FIG7 , during the third PRACH transmission, the terminal device first calculates the power corresponding to the first type PRACH transmission (referred to as calculated power). Since the calculated power is greater than or equal to the first threshold, the terminal device can perform a second type PRACH transmission. In an embodiment of the present application, the first power can be determined based on the calculated power, that is, the second power of the second type PRACH transmission can be determined based on the calculated power.

[0138] For condition 3, referring to FIG8 , during the third PRACH transmission, since the number of transmissions is greater than the second threshold, the terminal device performs a second type of PRACH transmission. In an embodiment of the present application, the first power may be determined based on the transmit power corresponding to the third PRACH transmission. The terminal device may calculate the transmit power corresponding to the third PRACH transmission based on the first type of PRACH transmission.

[0139] In some embodiments, if the terminal device performs a second type of PRACH transmission this time when the condition is met, the transmission that meets the condition is the next transmission after the last transmission. If the terminal device performs a second type of PRACH transmission the next time when the condition is met, the transmission that meets the condition is the same transmission as the last transmission.

[0140] In some embodiments, regardless of which of the above conditions is used, the terminal device can determine the second power based on the maximum transmit power. In other words, regardless of which of the above jumps 1 to 3 is used, the terminal device can determine the second power based on the maximum transmit power.

[0141] In some embodiments, the second power may be equal to the first power, or the second power may be determined based on the adjusted first power.

[0142] For the second type of PRACH transmission, the network device can improve the detection performance of PRACH by combining reception. That is to say, the second type of PRACH transmission can improve the coverage of PRACH to a certain extent. Therefore, the embodiment of the present application can make certain adjustments to the first power and determine the second power based on the adjusted first power. As an example, the second power can be determined based on the first power and the power offset. The power offset can be greater than 0 or less than 0. In some embodiments, the second power can be the sum of the first power and the power offset. For example, the second power = first power + power offset. Of course, in some embodiments, the second power = first power - power offset.

[0143] In some embodiments, the power offset may be determined based on the number of PRACHs included in a transmission process of the second type PRACH transmission. For example, if a transmission process includes more PRACHs, the power offset may be larger; if a transmission process includes fewer PRACHs, the power offset may be smaller.

[0144] In some embodiments, the first power may be the maximum transmit power of the terminal device. The terminal device may reduce the first offset value (e.g., 1 dB) based on the maximum transmit power to obtain the second power. Taking condition 1 as an example, the terminal device may reduce the first offset value based on the maximum transmit power to use as the transmit power for the second type of PRACH transmission.

[0145] In some embodiments, taking conditions 2 and 3 as an example, the first power may be the power calculated by switching power control (referred to as open-loop power). In this case, the terminal device may perform a second offset based on the open-loop power to obtain the second power.

[0146] For example, the second power may be determined based on the following formula:

[0147] P PRACH,b,f,c (i) = min{P CMAX,f,c (i),P PRACH,target,f,c +PL b,f,c +α}

[0148] Wherein, α is the second offset value, which can be greater than or less than 0.

[0149] The second offset value may be greater than 0 or less than 0, and this embodiment of the present application does not specifically limit this.

[0150] In some embodiments, the second power may be determined based on the following formula:

[0151] P PRACH,b,f,c (i) = min{P CMAX,f,c (i), min{P CMAX,f,c (i),P PRACH,target,f,c +PL b,f,c}+β}

[0152] Where β is the offset value. β can be greater than or less than 0. This formula applies to all conditions 1 to 3 above.

[0153] In the traditional random access process, the network device will configure the maximum number of PRACH transmissions for the terminal device. When the number of PRACH transmissions reaches the maximum number of transmissions and the RAR sent by the network device is still not received, the terminal device can determine that this random access has failed. The embodiment of the present application does not specifically limit the method for configuring the maximum number of transmissions by the network device. For example, the network device can configure the maximum number of transmissions through the information element preambleTransMax. The values ​​of preambleTransMax include 3, 4, 5, 6, 7, 8, 10, 20, 50, 100, and 200.

[0154] The number of transmissions by the terminal device can be counted by a counter (PREAMBLE_POWER_RAMPING_COUNTER). Each time the terminal device transmits a PRACH, the counter is incremented by 1. When the counter value reaches the maximum number of transmissions and the terminal device still does not receive the RAR sent by the network device, it can determine that the random access has failed.

[0155] In the embodiment of the present application, the second type of PRACH transmission needs to meet certain conditions to be triggered, that is, the terminal device can first perform a first type of PRACH transmission, and then perform a second type of PRACH transmission. In other words, during the entire random access process, the terminal device needs to first perform one or more first type of PRACH transmissions, and then perform a second type of PRACH transmission when certain conditions are met. For a random access process that includes two types of PRACH transmissions, there is currently no clear way to specify the maximum number of transmissions.

[0156] Based on this, the embodiments of the present application provide two methods for specifying the maximum number of transmissions, and these two methods are introduced below.

[0157] Method 1: The number of transmissions of the first type PRACH transmission and the number of transmissions of the second type PRACH are counted together. The first type PRACH transmission and the second type PRACH transmission correspond to the same counter. That is, the total number of transmissions of the first type PRACH transmission and the second type PRACH transmission corresponds to a maximum number of transmissions. Each time the terminal device performs a first type PRACH transmission, the counter is incremented by 1. Each time the terminal device performs a second type PRACH transmission, the counter is also incremented by 1. When the total value of the counter reaches the maximum number of transmissions preambleTransMax, and the RAR sent by the network device is still not received, the terminal device can determine that the random access has failed.

[0158] The counting method of PRACH transmission is described below with reference to FIG9 .

[0159] 9 shows the first two random access processes as first type PRACH transmissions and the subsequent ones as second type PRACH transmissions. Since first type PRACH transmissions and second type PRACH transmissions are counted together, the first second type PRACH transmission can be counted as the third transmission.

[0160] Mode 2: The number of transmissions of the first type of PRACH transmission and the number of transmissions of the second type of PRACH transmission are counted separately. The first type of PRACH transmission and the second type of PRACH transmission correspond to different counters. Hereinafter, the counter corresponding to the first type of PRACH transmission is referred to as counter 1, and the counter corresponding to the second type of PRACH transmission is referred to as counter 2. The first type of PRACH transmission and the second type of PRACH transmission each correspond to a maximum number of transmissions. The first type of PRACH transmission corresponds to a maximum number of transmissions (denoted as preambleTransMax 1), and the second type of PRACH transmission corresponds to another maximum number of transmissions (denoted as preambleTransMax 2). preambleTransMax 1 and preambleTransMax 2 can be equal or different.

[0161] Type 1 PRACH transmissions are counted separately. The network device can configure a maximum number of transmissions, preambleTransMax 1, for Type 1 PRACH transmissions. Each time a terminal device performs a Type 1 PRACH transmission, Counter 1 increments by 1. When Counter 1 reaches the maximum number of transmissions, preambleTransMax 1, and the terminal device still has not received a RAR from the network device, the terminal device determines that random access has failed.

[0162] Type 2 PRACH transmissions are counted separately. The network device can configure a maximum number of transmissions, preambleTransMax 2, for Type 2 PRACH transmissions. Each time a terminal device performs a Type 2 PRACH transmission, Counter 2 increments by 1. When Counter 2 reaches the maximum number of transmissions, preambleTransMax 2, and the terminal device still has not received a RAR from the network device, the terminal device determines that random access has failed.

[0163] The counting method of PRACH transmission is described below with reference to FIG10 .

[0164] 10 shows the first two random access procedures as first type PRACH transmissions and the subsequent ones as second type PRACH transmissions. Since first type PRACH transmissions and second type PRACH transmissions are counted separately, the first second type PRACH transmission can be counted as the first transmission.

[0165] The method embodiment of the present application is described in detail above in conjunction with Figures 1 to 10. The device embodiment of the present application is described in detail below in conjunction with Figures 11 to 13. It should be understood that the description of the method embodiment corresponds to the description of the device embodiment. Therefore, for parts not described in detail, reference can be made to the above method embodiment.

[0166] FIG11 is a schematic diagram of a terminal device provided in an embodiment of the present application. The terminal device 1100 may be any of the terminal devices described above. The terminal device 1100 may include a transmission unit 1110.

[0167] The transmission unit 1110 is configured to perform a second type of PRACH transmission if the transmission parameters corresponding to the first type of PRACH transmission meet the conditions, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

[0168] In some embodiments, the transmission parameters include one or more of the following information: transmit power, number of transmissions, and downlink path loss.

[0169] In some embodiments, the conditions include one or more of the following: the transmission power corresponding to the first type PRACH transmission reaches the maximum transmission power of the terminal device; the transmission power corresponding to the first type PRACH transmission is greater than or equal to a first threshold; and the number of transmissions corresponding to the first type PRACH transmission is greater than or equal to a second threshold.

[0170] In some embodiments, the transmit power corresponding to the second type PRACH transmission is determined based on a first power, and the first power is determined based on the transmit power corresponding to the first type PRACH transmission or the maximum transmit power of the terminal device.

[0171] In some embodiments, the first power is determined based on one or more of: a transmit power corresponding to a last transmission in the first type of PRACH transmission; and a transmit power corresponding to the first type of PRACH transmission when the condition is met.

[0172] In some embodiments, the transmit power corresponding to the second type of PRACH transmission is the transmit power of any one of the multiple PRACH transmissions.

[0173] In some embodiments, the transmit power corresponding to the second type of PRACH transmission is the transmit power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

[0174] In some embodiments, the transmit power corresponding to the second type PRACH transmission is determined based on the first power and a power offset.

[0175] In some embodiments, the transmit power corresponding to the second type PRACH transmission is the sum of the first power and the power offset.

[0176] In some embodiments, the number of transmissions of the first type PRACH transmission and the number of transmissions of the second type PRACH transmission are counted uniformly, or the number of transmissions of the first type PRACH transmission and the number of transmissions of the second type PRACH transmission are counted separately.

[0177] FIG12 is a schematic diagram of a network device provided in an embodiment of the present application. The network device 1200 may be any terminal device described above. The network device 1200 may include a receiving unit 1210.

[0178] The receiving unit 1210 is configured to receive a PRACH transmitted based on a second type of PRACH transmission mode if the transmission parameters corresponding to the first type of physical random access channel PRACH transmission meet the conditions, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

[0179] In some embodiments, the transmission parameters include one or more of the following information: transmit power, number of transmissions, and downlink path loss.

[0180] In some embodiments, the conditions include one or more of the following: the transmission power corresponding to the first type PRACH transmission reaches the maximum transmission power of the terminal device; the transmission power corresponding to the first type PRACH transmission is greater than or equal to a first threshold; and the number of transmissions corresponding to the first type PRACH transmission is greater than or equal to a second threshold.

[0181] In some embodiments, the transmit power corresponding to the second type PRACH transmission is determined based on a first power, and the first power is determined based on the transmit power corresponding to the first type PRACH transmission or the maximum transmit power of the terminal device.

[0182] In some embodiments, the first power is determined based on one or more of: a transmit power corresponding to a last transmission in the first type of PRACH transmission; and a transmit power corresponding to the first type of PRACH transmission when the condition is met.

[0183] In some embodiments, the transmit power corresponding to the second type of PRACH transmission is the transmit power of any one of the multiple PRACH transmissions.

[0184] In some embodiments, the transmit power corresponding to the second type of PRACH transmission is the transmit power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

[0185] In some embodiments, the transmit power corresponding to the second type PRACH transmission is determined based on the first power and a power offset.

[0186] In some embodiments, the transmit power corresponding to the second type PRACH transmission is the sum of the first power and the power offset.

[0187] In some embodiments, the number of transmissions of the first type PRACH transmission and the number of transmissions of the second type PRACH transmission are counted uniformly, or the number of transmissions of the first type PRACH transmission and the number of transmissions of the second type PRACH transmission are counted separately.

[0188] Figure 13 is a schematic block diagram of a communication device according to an embodiment of the present application. The dashed lines in Figure 13 indicate that the unit or module is optional. Apparatus 1300 may be used to implement the method described in the above method embodiment. Apparatus 1300 may be a chip, a terminal device, or a network device.

[0189] The device 1300 may include one or more processors 1310. The processor 1310 may support the device 1300 to implement the method described in the above method embodiment. The processor 1310 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0190] The apparatus 1300 may further include one or more memories 1320. The memories 1320 store programs that can be executed by the processor 1310, causing the processor 1310 to perform the methods described in the above method embodiments. The memories 1320 may be independent of the processor 1310 or integrated into the processor 1310.

[0191] The apparatus 1300 may further include a transceiver 1330. The processor 1310 may communicate with other devices or chips via the transceiver 1330. For example, the processor 1310 may transmit and receive data with other devices or chips via the transceiver 1330.

[0192] The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0193] The present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal or network device provided in the present application, and the program causes a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0194] The embodiments of the present application also provide a computer program. The computer program can be applied to the terminal or network device provided in the embodiments of the present application, and the computer program enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0195] It should be understood that the terms "system" and "network" in this application can be used interchangeably. In addition, the terms used in this application are only used to explain the specific embodiments of this application and are not intended to limit this application. The terms "first", "second", "third", and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0196] In the embodiments of this application, the term "indication" may refer to a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" may refer to a direct indication of B, e.g., B can obtain information through A; it may refer to an indirect indication of B, e.g., A indicates C, e.g., B can obtain information through C; or it may refer to an association between A and B.

[0197] In the embodiment of the present application, "B corresponding to A" means that B is associated with A and B can be determined based on A. However, it should be understood that determining B based on A does not mean determining B based solely on A, but B can also be determined based on A and / or other information.

[0198] In the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and indication, configuration and configuration, etc.

[0199] In the embodiments of the present application, "pre-definition" or "pre-configuration" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., a terminal device and a network device). The present application does not limit the specific implementation method. For example, pre-definition may refer to information defined in a protocol.

[0200] In the embodiments of the present application, the “protocol” may refer to a standard protocol in the communications field, for example, it may include an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present application does not limit this.

[0201] In the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0202] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0203] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0204] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0205] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0206] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0207] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for wireless communication, characterized in that, Including: If the transmission parameters corresponding to the first type of Physical Random Access Channel (PRACH) transmission meet the conditions, the terminal device performs the second type of PRACH transmission, where one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

2. The method according to claim 1, characterized in that The transmission parameters include one or more of the following information: transmit power, number of transmissions, and downlink path loss.

3. The method according to claim 2, wherein The conditions include one or more of the following: The transmit power corresponding to the first type of PRACH transmission reaches the maximum transmit power of the terminal device; The transmit power corresponding to the first type of PRACH transmission is greater than or equal to a first threshold; and The number of transmissions corresponding to the first type of PRACH transmission is greater than or equal to a second threshold.

4. The method according to any one of claims 1 to 3, characterized in that, The transmit power corresponding to the second type of PRACH transmission is determined based on a first power, and the first power is determined based on the transmit power corresponding to the first type of PRACH transmission or the maximum transmit power of the terminal device.

5. The method according to claim 4, characterized in that The first power is determined based on one or more of the following: The transmit power corresponding to the last transmission in the first type of PRACH transmission; and When the conditions are met, the transmit power corresponding to the first type of PRACH transmission.

6. The method according to claim 4 or 5, characterized in that, The transmit power corresponding to the second type of PRACH transmission is the transmit power of any one of the multiple PRACH transmissions.

7. The method according to claim 6, wherein The transmit power corresponding to the second type of PRACH transmission is the transmit power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

8. The method according to any one of claims 4 to 7, characterized in that The transmit power corresponding to the second type of PRACH transmission is determined based on the first power and a power offset.

9. The method according to claim 8, wherein The transmit power corresponding to the second type of PRACH transmission is the sum of the first power and the power offset.

10. The method according to any one of claims 1-9, characterized in that, The number of transmissions of the first type of PRACH transmission and the number of transmissions of the second type of PRACH transmission are counted uniformly, or The number of transmissions of the first type of PRACH transmission and the number of transmissions of the second type of PRACH transmission are counted separately.

11. A method for wireless communication, characterized in that, Including: If the transmission parameters corresponding to the first type of Physical Random Access Channel (PRACH) transmission meet the conditions, the network device receives the PRACH transmitted based on the second type of PRACH transmission mode, where one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

12. The method according to claim 11, wherein The transmission parameters include one or more of the following information: transmit power, number of transmissions, and downlink path loss.

13. The method according to claim 12, wherein The conditions include one or more of the following: The transmit power corresponding to the first type of PRACH transmission reaches the maximum transmit power of the terminal device; The transmit power corresponding to the first type of PRACH transmission is greater than or equal to a first threshold; and The number of transmissions corresponding to the first type of PRACH transmission is greater than or equal to a second threshold.

14. The method according to any one of claims 11-13, characterized in that, The transmit power corresponding to the second type of PRACH transmission is determined based on a first power, and the first power is determined based on the transmit power corresponding to the first type of PRACH transmission or the maximum transmit power of the terminal device.

15. The method according to claim 14, wherein The first power is determined based on one or more of the following: The transmit power corresponding to the last transmission in the first type of PRACH transmission; and When the condition is satisfied, the transmit power corresponding to the first type of PRACH transmission.

16. The method according to claim 14 or 15, characterized in that, The transmit power corresponding to the second type of PRACH transmission is the transmit power of any one of the multiple PRACH transmissions.

17. The method according to claim 16, wherein The transmit power corresponding to the second type of PRACH transmission is the transmit power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

18. The method according to any one of claims 14-17, characterized in that The transmit power corresponding to the second type of PRACH transmission is determined based on the first power and a power offset.

19. The method according to claim 18, wherein The transmit power corresponding to the second type of PRACH transmission is the sum of the first power and the power offset.

20. The method according to any one of claims 11-19, characterized in that, The number of transmissions of the first type of PRACH transmission and the number of transmissions of the second type of PRACH transmission are counted uniformly, or The number of transmissions of the first type of PRACH transmission and the number of transmissions of the second type of PRACH transmission are counted separately.

21. A terminal device, characterized in that, Including: A transmission unit, configured to perform a second type of PRACH transmission if the transmission parameters corresponding to the first type of physical random access channel (PRACH) transmission satisfy a condition, where one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

22. The terminal device according to claim 21, wherein The transmission parameters include one or more of the following information: transmit power, number of transmissions, and downlink path loss.

23. The terminal device according to claim 22, wherein The condition includes one or more of the following: The transmit power corresponding to the first type of PRACH transmission reaches the maximum transmit power of the terminal device; The transmit power corresponding to the first type of PRACH transmission is greater than or equal to a first threshold; and The number of transmissions of the first type of PRACH transmission is greater than or equal to a second threshold.

24. The terminal device according to any one of claims 21-23, characterized in that, The transmit power corresponding to the second type of PRACH transmission is determined based on a first power, and the first power is determined based on the transmit power corresponding to the first type of PRACH transmission or the maximum transmit power of the terminal device.

25. The terminal device according to claim 24, wherein, The first power is determined based on one or more of the following: The transmit power corresponding to the last transmission in the first type of PRACH transmission; and When the condition is satisfied, the transmit power corresponding to the first type of PRACH transmission.

26. The terminal device according to claim 24 or 25, characterized in that, The transmit power corresponding to the second type of PRACH transmission is the transmit power of any one of the multiple PRACH transmissions.

27. The terminal device according to claim 26, wherein The transmit power corresponding to the second type of PRACH transmission is the transmit power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

28. The terminal device according to any one of claims 24-27, characterized in that, The transmit power corresponding to the second type of PRACH transmission is determined based on the first power and a power offset.

29. The terminal device according to claim 28, wherein The transmission power corresponding to the second type of PRACH transmission is the sum of the first power and the power offset.

30. The terminal device according to any one of claims 21-29, characterized in that, The transmission times of the first type of PRACH transmission and the transmission times of the second type of PRACH transmission are counted uniformly, or The transmission times of the first type of PRACH transmission and the transmission times of the second type of PRACH transmission are counted separately.

31. A network device, characterized in that, Comprising: A receiving unit, configured to receive a PRACH transmitted based on a second type of PRACH transmission manner if the transmission parameters corresponding to a first type of physical random access channel (PRACH) transmission meet a condition, wherein one transmission process of the first type of PRACH transmission includes one PRACH transmission, and one transmission process of the second type of PRACH transmission includes multiple PRACH transmissions.

32. The network device according to claim 31, wherein The transmission parameters include one or more of the following information: transmission power, transmission times, and downlink path loss.

33. The network device according to claim 32, characterized in that, The condition includes one or more of the following: The transmission power corresponding to the first type of PRACH transmission reaches the maximum transmission power of the terminal device; The transmission power corresponding to the first type of PRACH transmission is greater than or equal to a first threshold; and The transmission times corresponding to the first type of PRACH transmission are greater than or equal to a second threshold.

34. The network device according to any one of claims 31-33, characterized in that The transmission power corresponding to the second type of PRACH transmission is determined based on a first power, and the first power is determined based on the transmission power corresponding to the first type of PRACH transmission or the maximum transmission power of the terminal device.

35. The network device according to claim 34, wherein The first power is determined based on one or more of the following: The transmission power corresponding to the last transmission in the first type of PRACH transmission; and When the condition is satisfied, the transmission power corresponding to the first type of PRACH transmission.

36. The network device according to claim 34 or 35, characterized in that, The transmission power corresponding to the second type of PRACH transmission is the transmission power of any one of the multiple PRACH transmissions.

37. The network device according to claim 36, characterized in that, The transmission power corresponding to the second type of PRACH transmission is the transmission power of the PRACH with the earliest transmission time among the multiple PRACH transmissions.

38. The network device according to any one of claims 34-37, characterized in that, The transmission power corresponding to the second type of PRACH transmission is determined based on the first power and a power offset.

39. The network device according to claim 38, wherein The transmission power corresponding to the second type of PRACH transmission is the sum of the first power and the power offset.

40. The network device according to any one of claims 31-39, characterized in that, The transmission times of the first type of PRACH transmission and the transmission times of the second type of PRACH transmission are counted uniformly, or The transmission times of the first type of PRACH transmission and the transmission times of the second type of PRACH transmission are counted separately.

41. A terminal device, characterized in that, Comprising a memory and a processor, the memory is used to store a program, and the processor is used to call the program in the memory to enable the terminal to execute the method according to any one of claims 1-10.

42. A network device, characterized in that, Comprising a memory and a processor, the memory is used to store a program, and the processor is used to call the program in the memory to enable the network device to execute the method according to any one of claims 11-20.

43. A device, characterized in that, Comprising a processor for invoking a program from a memory to cause the device to execute the method according to any one of claims 1-10.

44. A device, characterized in that, Comprising a processor for invoking a program from a memory to cause the device to execute the method according to any one of claims 11-20.

45. A chip, characterized in that, Comprising a processor for invoking a program from a memory such that a device installed with the chip executes the method according to any one of claims 1-10.

46. A chip, characterized in that, Comprising a processor for invoking a program from a memory such that a device installed with the chip executes the method according to any one of claims 11-20.

47. A computer-readable storage medium, characterized in that, Having stored thereon a program which causes a computer to execute the method according to any one of claims 1-10.

48. A computer-readable storage medium, characterized in that, Having stored thereon a program which causes a computer to execute the method according to any one of claims 11-20.

49. A computer program product, characterized in that, Comprising a program which causes a computer to execute the method according to any one of claims 1-10.

50. A computer program product, characterized in that, Comprising a program which causes a computer to execute the method according to any one of claims 11-20.

51. A computer program, characterized in that, The computer program causes a computer to execute the method according to any one of claims 1-10.

52. A computer program, characterized in that, The computer program causes a computer to execute the method according to any one of claims 11-20.

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