COMMUNICATION METHOD AND COMMUNICATION DEVICE

Abstract

To provide a communication method and a communication apparatus that minimize the possibility of a terminal device falling back to four-stage random access and improve the success rate of random access of the terminal device.SOLUTION: In a communication system, a communication method includes a first network device receiving a first report from a terminal device, and performing processing based on the first report. The first report includes first information, and the first information indicates whether the terminal device will passively fall back from 2-stage random access to 4-stage random access or actively fall back from the 2-stage random access to the 4-stage random access.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present application relate to the field of communications, and in particular to a communication method and device. [Background technology]

[0002] In long term evolution (LTE) communication or new radio (NR) communication, a terminal device may synchronize with a network side to set up a connection to the network side through a random access process and obtain a Cell Radio Network Temporary Identifier (C-RNTI). Currently, there are a four-step random access process and a two-step random access process. In a possible implementation, if the execution of the two-step random access process fails, the terminal device may fall back to the four-step random access process. Currently, the network side cannot optimize the configuration of the two-step random access process. As a result, the terminal device may frequently fall back to the four-step random access process, reducing the success rate of the random access of the terminal device. Summary of the Invention

[0003] The embodiments of the present application provide a communication method and a communication device to minimize the possibility that a terminal device falls back to four-stage random access and improve the success rate of random access of a terminal device.

[0004] According to a first aspect, a communication method is provided, comprising: a first network device receiving a first report from a terminal device, the first report having first information, the first information indicating that the terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access; the first information indicating a manner in which the terminal device falls back from two-stage random access to four-stage random access; and the first information indicating whether the terminal device falls back from two-stage random access to four-stage random access or whether the terminal device receives a fallback instruction. The first network device may further perform processing based on the first report.

[0005] In this embodiment of the present application, the network side adjusts the corresponding configuration information according to the fallback manner of the terminal device, thereby improving the success rate of random access of the terminal device, and avoiding frequent two-stage random access fallback caused by improper configuration on the network side as much as possible. For example, when the first information indicates that the terminal device is performing active fallback, the two-stage random access configuration parameters may be adjusted to reduce the number of fallbacks of the terminal device. For example, the maximum number of transmissions of the random access preamble or msgA in the two-stage random access process is increased. The terminal device may attempt to transmit msgA multiple times to initiate the two-stage random access, so that the success rate of the random access may be improved. Alternatively, when the first information indicates that the terminal device is performing passive fallback, the network side may adjust the time-frequency resources of the two-stage random access to allocate sufficient time-frequency resources to the terminal device for transmitting data related to the two-stage random access (e.g., msgA), thereby improving the success rate of the random access.

[0006] Referring to the first aspect, in a first possible implementation of the first aspect, the first report further includes second information, and the second information indicates a two-stage quality threshold for random access.

[0007] The second information is used by the network device to determine the quality threshold of the two-stage random access, so that the quality threshold of the two-stage random access can be increased, and the terminal device can select the four-stage random access as much as possible. To some extent, the terminal device is prevented from frequently falling back to the four-stage random access process, thereby improving the success rate of the random access of the terminal device.

[0008] Referring to the first aspect, or a first possible implementation of the first aspect, in a second possible implementation of the first aspect, the first report further has third information, and the third information has at least one of the following information: information about a physical uplink shared channel PUSCH configured for the terminal device in two-stage random access, random access configuration information in two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

[0009] The third information is used by the network device to determine two-stage random access configuration information. After receiving the first report, the network device can optimize the two-stage random access configuration information to avoid as much as possible the two-stage random access failure of the terminal device caused by improper configuration, and improve the success rate of the random access of the terminal device.

[0010] Referring to the first aspect, or the first or second possible implementation of the first aspect, in a third possible implementation of the first aspect, the first report further has fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access.

[0011] The fourth information is used by the network device to determine two-stage random access configuration information that causes the current two-stage random access fallback, so that the two-stage random access configuration information is adjusted, the success rate of the terminal device's execution of two-stage random access is improved, and to a certain extent, the terminal device is prevented from frequently falling back to four-stage random access.

[0012] With reference to the first aspect or any one of the first to third possible implementations of the first aspect, in a fourth possible implementation of the first aspect, the first report further has fifth information, and the fifth information indicates cell information for the terminal device to perform two-stage random access.

[0013] The fifth information is used by the network device to determine a network device corresponding to the first report based on the fifth information and to forward some or all of the information in the first report to the network device.

[0014] With reference to the first aspect, or any one of the first to fourth possible implementations of the first aspect, in a fifth possible implementation of the first aspect, the first report further has sixth information, wherein the sixth information indicates at least one of the following information: a network type of a first cell, a frequency type of the first cell, a service type of the first cell, a type of the first cell, and the first cell is a cell in which the terminal device performs two-stage random access.

[0015] The sixth information is used by the network device to determine characteristics of a cell in which the terminal device performs two-stage random access, so that the two-stage random access configuration information is optimized based on the cell characteristics, and the success rate of the random access of the terminal device is improved.

[0016] With reference to the first aspect, or any one of the first to fifth possible implementations of the first aspect, in a sixth possible implementation of the first aspect, the step of the first network device performing processing based on the first report includes a step of the first network device transmitting some or all of the information in the first report to a second network device.

[0017] In this embodiment of the present application, the first network device sends information related to the two-stage random access in the first report to the network device corresponding to the first report, i.e., the network device through which the terminal device performs the two-stage random access, so that the network device optimizes the two-stage random access configuration information to improve the success rate of the random access of the terminal device.

[0018] Referring to the sixth possible implementation of the first aspect, in a seventh possible implementation of the first aspect, the first network device is a centralized unit CU and the second network device is a distributed unit DU, or the first network device and the second network device are different base stations.

[0019] In this embodiment of the present application, two-stage random access related information transmission and transmission between base stations are supported, and two-stage random access related information transmission and transmission between CU and DU are further supported. In the above scenario, two-stage random access configuration information is optimized, so that the success rate of random access of terminal device can be improved.

[0020] According to a second aspect, a communication method is provided, the method including: a terminal device determining first information, the first information indicating that the terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access. The terminal device transmits a first report to a first network device, the first report including the first information.

[0021] Referring to the second aspect, in a first possible implementation of the second aspect, the first report further includes second information, where the second information indicates a quality threshold for two-stage random access.

[0022] Referring to the second aspect, or a first possible implementation of the second aspect, in a second possible implementation of the second aspect, the first report further includes third information, and the third information includes at least one of the following information: information about a physical uplink shared channel PUSCH configured for the terminal device in the two-stage random access, random access configuration information in the two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

[0023] Referring to the second aspect, or the first or second possible implementation of the second aspect, in a third possible implementation of the second aspect, the first report further has fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access.

[0024] With reference to the second aspect, or any one of the first to third possible implementations of the second aspect, in a fourth possible implementation of the second aspect, the first report further includes fifth information, where the fifth information indicates cell information for the terminal device to perform two-stage random access.

[0025] With reference to the second aspect, or any one of the first to fourth possible implementations of the second aspect, in a fifth possible implementation of the second aspect, the first report further has sixth information, wherein the sixth information indicates at least one of the following information: a network type of a first cell, a frequency type of the first cell, a service type of the first cell, a type of the first cell, and the first cell is a cell in which the terminal device performs two-stage random access.

[0026] According to a third aspect, a first communication apparatus is provided, the apparatus including: a communication unit configured to receive a first report from a terminal device, the first report including first information indicating that the terminal device passively falls back from two-stage random access to four-stage random access, or actively falls back from two-stage random access to four-stage random access; and a processing unit configured to perform processing based on the first report.

[0027] Referring to the third aspect, in a first possible implementation of the third aspect, the first report further includes second information, where the second information indicates a quality threshold for two-stage random access.

[0028] Referring to the third aspect, or the first or second possible implementation of the third aspect, in a third possible implementation of the third aspect, the first report further includes third information, and the third information includes at least one of the following information: information about a physical uplink shared channel PUSCH configured for the terminal device in two-stage random access, random access configuration information in the two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

[0029] With reference to the third aspect, or any one of the first to third possible implementations of the third aspect, in a fourth possible implementation of the third aspect, the first report further has fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access.

[0030] With reference to the third aspect, or any one of the first to fourth possible implementations of the third aspect, in a fifth implementation of the third aspect, the first report further has fifth information, and the fifth information indicates cell information for the terminal device to perform two-stage random access.

[0031] With reference to the third aspect or any one of the first to fifth possible implementations of the third aspect, in a sixth possible implementation of the third aspect, the first report further has sixth information, wherein the sixth information indicates at least one of the following information: a network type of a first cell, a frequency type of the first cell, a service type of the first cell, a type of the first cell, and the first cell is a cell in which the terminal device performs two-stage random access.

[0032] With reference to the third aspect, or any one of the first to sixth possible implementations of the third aspect, in a seventh possible implementation of the third aspect, the processing unit is specifically configured to transmit, using the communication unit, some or all of the information in the first report to a second communication device.

[0033] With reference to the seventh possible implementation of the third aspect, in an eighth possible implementation of the third aspect, the first communication device is a centralized unit CU and the second communication device is a distributed unit DU, or the first communication device and the second communication device are different base stations.

[0034] According to a fourth aspect, a communication apparatus is provided, the communication apparatus including: a processing unit configured to determine first information, the first information indicating that a terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access; and a communication unit configured to send a first report to a first network device, the first report including the first information.

[0035] Referring to the fourth aspect, in a first possible implementation of the fourth aspect, the first report further includes second information, where the second information indicates a quality threshold for two-stage random access.

[0036] Referring to the fourth aspect, or a first possible implementation of the fourth aspect, in a second possible implementation of the fourth aspect, the first report further includes third information, and the third information includes at least one of the following information: information about a physical uplink shared channel PUSCH configured for the terminal device in two-stage random access, random access configuration information in the two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

[0037] Referring to the fourth aspect, or the first or second possible implementation of the fourth aspect, in a third possible implementation of the fourth aspect, the first report further has fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access.

[0038] With reference to the fourth aspect, or any one of the first to third possible implementations of the fourth aspect, in a fourth possible implementation of the fourth aspect, the first report further has fifth information, and the fifth information indicates cell information for the terminal device to perform two-stage random access.

[0039] With reference to the fourth aspect, or any one of the first to fourth possible implementations of the fourth aspect, in a fifth possible implementation of the fourth aspect, the first report further has sixth information, wherein the sixth information indicates at least one of the following information: a network type of a first cell, a frequency type of the first cell, a service type of the first cell, a type of the first cell, and the first cell is a cell in which the terminal device performs two-stage random access.

[0040] According to a fifth aspect, there is provided a communications device including at least one processor and a memory, the at least one processor coupled to the memory, and the memory configured to store a computer program.

[0041] At least one processor is configured to execute a computer program stored in the memory to enable the apparatus to perform a method according to the first aspect and any one of the implementations of the first aspect, or a method according to the second aspect and any one of the implementations of the second aspect.

[0042] According to a sixth aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing instructions, which when executed on a communication device according to the third aspect and any one of the implementations of the third aspect, enables the communication device to perform the communication method according to the first aspect and any one of the implementations of the first aspect.

[0043] According to a seventh aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing instructions, which when executed on a communication device according to the fourth aspect and any one of the implementations of the fourth aspect, enables the communication device to perform the communication method according to the second aspect and any one of the implementations of the second aspect.

[0044] According to an eighth aspect, a wireless communication device is provided. The communication device includes a processor for implementing the method according to the first aspect and any one of the implementations of the first aspect, for example for use in the communication device. The communication device may be, for example, a chip system. In a possible implementation, the chip system further includes a memory, the memory being configured to store program instructions and data necessary to implement the functions of the method according to the first aspect.

[0045] According to a ninth aspect, a wireless communication device is provided. The communication device includes a processor for implementing the functions or methods according to the second aspect and any one of the implementations of the second aspect, for example for use in the communication device. The communication device may be, for example, a chip system. In a possible implementation, the chip system further includes a memory, the memory being configured to store program instructions and data necessary to implement the functions of the method according to the second aspect.

[0046] The chip system in the above-mentioned embodiment may be a system-on-a-chip (SOC), a baseband chip, etc. The baseband chip may include a processor, a channel encoder, a digital signal processor, a modem, an interface module, etc.

[0047] According to a tenth aspect, there is provided a communication system, the communication system including a communication device according to the third aspect, any one of the possible implementations of the third aspect, the fourth aspect, and any one of the possible implementations of the fourth aspect, or A communication device according to the fifth and sixth aspects is also included.

[0048] In a possible implementation, the communication system further includes a second network device, the second network device configured to receive some or all of the information in the first report and perform processing based on some or all of the information about the first report. [Brief description of the drawings]

[0049] [Figure 1] FIG. 1 is an architecture diagram of a communication system according to an embodiment of the present application.

[0050] [Diagram 2] FIG. 2 is another architecture diagram of a communication system according to an embodiment of the present application.

[0051] [Diagram 3] FIG. 2 is a structural block diagram of a network device according to an embodiment of the present application.

[0052] [Figure 4] FIG. 2 is another structural block diagram of a network device according to an embodiment of the present application.

[0053] [Diagram 5] 1 is a flowchart of random access according to an embodiment of the present application.

[0054] [Figure 6] 4 is another flowchart of random access according to an embodiment of the present application;

[0055] [Figure 7a] FIG. 2 is a structural block diagram of a communication device according to an embodiment of the present application.

[0056] [Figure 7b] FIG. 2 is another structural block diagram of a communication device according to an embodiment of the present application.

[0057] [Figure 8] 1 is a schematic flowchart of a communication method according to an embodiment of the present application;

[0058] [Figure 9] 4 is another schematic flowchart of a communication method according to an embodiment of the present application.

[0059] [Figure 10]4 is another schematic flowchart of a communication method according to an embodiment of the present application.

[0060] [Figure 11] FIG. 2 is another structural block diagram of a communication device according to an embodiment of the present application. [Figure 12] FIG. 2 is another structural block diagram of a communication device according to an embodiment of the present application. [Figure 13] FIG. 2 is another structural block diagram of a communication device according to an embodiment of the present application. [Figure 14] FIG. 2 is another structural block diagram of a communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] Figure 1 is a schematic diagram of a communication system to which the technical solutions provided in the present application are applicable. The communication system may include at least one network apparatus (a network device 100 is shown) and at least one terminal device (only a terminal device 201 and a terminal device 202 are shown in the figure). Figure 1 is just a schematic diagram and does not limit the applicable scenarios of the technical solutions provided in the present application.

[0062] The network device 100 may be any device having a radio transceiver function. The network device includes, but is not limited to, evolved base stations in LTE (E-UTRAN NodeB, e-NodeB, or eNB), base stations in 5G or new radio (NR) access technologies (gNodeB or gNB) or transmission / reception points (TRP), future evolved base stations in 3GPP, access nodes, radio relay nodes, or radio backhaul nodes in Wi-Fi systems, etc. The base stations may be macro base stations, micro base stations, pico base stations, small cells, relay stations, balloon stations, etc. The multiple base stations may support the network using the same technology as described above, or may support the network using different technologies than described above. The base stations may include one or more co-sited or non-co-sited TRPs. Alternatively, the network device may be a radio controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. Alternatively, the network device may be a server, a wearable device, an in-vehicle device, etc. In the following, an example in which the network device is a base station is used to provide an explanation. The multiple network devices may be the same type of base station, or may be different types of base stations. The base station may communicate with the terminal device, or may communicate with the terminal device via a relay station. The terminal device may communicate with multiple base stations using different technologies. For example, the terminal device may communicate with a base station supporting an LTE network, or may communicate with a base station supporting a 5G network, or may support dual connection with a base station supporting an LTE network and a base station supporting a 5G network.

[0063] The terminal device (e.g., the terminal device 200) is a device having a wireless transceiver function, and may be deployed on land, including indoor or outdoor, handheld, wearable, or vehicle-mounted deployment, on water (e.g., a ship), or in the air (e.g., an airplane, a balloon, and a satellite). The terminal device may be a mobile phone, a tablet, a computer having a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, an in-vehicle terminal device, a wireless terminal in self-driving, a wireless terminal in remote medical, 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, or a wearable terminal device. The application scenario is not limited to the embodiments of the present application. In some cases, the terminal may be referred to as a terminal device, user equipment (UE), access terminal device, in-vehicle terminal, industrial control terminal, UE unit, UE station, mobile station, remote station, remote terminal device, mobile device, UE terminal device, wireless communication device, UE agent, UE device, or the like. The terminal may be fixed or mobile. The terminal device of the present application may alternatively be an in-vehicle module, in-vehicle component, on-board component, on-vehicle chip, or on-vehicle unit built into the vehicle as one or more components or units. The vehicle implements the method of the present application using the in-vehicle module, on-vehicle component, on-vehicle component, on-vehicle chip, or on-vehicle unit built into the vehicle.

[0064] The network device communicates with a terminal device (e.g., terminal device 202 or terminal device 201) via a cellular link, and the terminal devices (e.g., terminal device 201 and terminal device 202) communicate with each other via a sidelink.

[0065] FIG. 2 is another schematic diagram of a communication system applicable to an embodiment of the present application. As shown in FIG. 2, the communication system may include at least two network devices, for example, the network device 101 and the network device 102 shown in FIG. 2. The communication system may further include at least one terminal device 200. The terminal device 200 may set up radio links to the network device 101 and the network device 102 using a dual connectivity (DC) technology or a multi-connectivity technology. The network device 101 may be, for example, a master base station, and the network device 102 may be, for example, a secondary base station. In this case, the network device 101 is the network device that the terminal device 200 accesses first and is responsible for radio resource control (RRC) communication with the terminal device 200. The network device 102 may be added during RRC reconfiguration and is configured to provide additional radio resources.

[0066] In addition, as shown in FIG. 2, one of the two network devices, for example, the network device 101, may be responsible for exchanging RRC messages with the terminal device 200 and may be responsible for interacting with the core network control plane entity. In this case, the network device 101 may be referred to as a master node (MN). For example, the master node may be a master evolved NodeB (MeNB) or a master next generation node base station (MgNB), which is not limited herein. The other network device, for example, the network device 102, may be referred to as a secondary node (SN). For example, the secondary node may be a secondary evolved NodeB (SeNB) or a secondary next generation node base station (SgNB), which is not limited herein. Multiple serving cells in a master node may form a master cell group (MCG) including one primary cell (PCell) and one or more optional secondary cells (SCells). Multiple serving cells in a secondary node may form a secondary cell group (SCG) including one primary secondary cell (PSCell) and one or more optional SCells. A serving cell is a cell configured by the network for a terminal to perform uplink and downlink transmissions.

[0067] Indeed, in FIG. 2, the network device 102 may be a master node, and the network device 101 may be a secondary node. This is not a limitation in the present application. In addition, for ease of understanding only, the figure shows a case where two network devices are wirelessly connected with a terminal device. Alternatively, the terminal device may have communication connections to three or more network devices simultaneously and may receive and transmit data. One of the three or more network devices may be responsible for exchanging RRC messages with the terminal and interacting with the core network control plane entity. In this case, the network device may be referred to as an MN, and the other network device may be referred to as an SN.

[0068] See Figure 3. The network device may include a centralized unit (CU) node and a distributed unit (DU) node. Optionally, the network device is a RAN device including a CU node and a DU node.

[0069] Please refer to Figure 4. The CU node can be divided into a control plane (CU-CP) and a user plane (CU-UP). The CU-CP is responsible for the control plane function, and mainly includes a radio resource control (RRC) layer and a packet data convergence protocol (PDCP)-C layer. The PDCP-C layer is mainly responsible for data encryption and decryption, integrity protection, data transmission, etc. in the control plane. The CU-UP is responsible for the user plane function, and mainly includes a service data adaptation protocol (SDAP) layer and a PDCP-U layer. The SDAP layer is mainly responsible for processing data in the core network and mapping flows to bearers. The PDCP-U layer is mainly responsible for encryption and decryption, integrity protection, header compression, serial number maintenance, data transmission, etc. in the data plane. The CU-CP and the CU-UP are connected via an E1 interface. The CU-CP indicates that the CU is connected to the core network via the NG interface and to the DU via the F1-C (control plane) interface. The CU-UP is connected to the DU via the F1-U (user plane) interface. Indeed, in another possible implementation, the PDCP-C layer is also present in the CU-UP.

[0070] Terms related to the embodiments of the present application will first be explained.

[0071] (1) Random Access

[0072] Random access is premised on communication between the terminal device and the network side. The terminal device can set up uplink synchronization through random access, obtain C-RNTI, and request the network to allocate uplink resources. Random access is not only used for initial access, but also for new cell access in handover procedure, access after radio link failure, and resumption of uplink synchronization and uplink resource request when there is uplink / downlink data transmission, etc.

[0073] After completing the random access process, the terminal device may obtain data bearer configuration information, and set up a bearer used for data transmission based on the configuration information to perform data communication with the network device.

[0074] Depending on whether it is contention-based or not, random access can be classified as contention-based random access (CBRA) and non-contention-based random access (non-contention-based or contention-free-based random access (CFRA)).

[0075] Based on the stage in the random access process, random access can be further classified into 4-step random access (4-stepRACH) and 2-step random access (2-stepRACH).

[0076] In some possible implementations, the terminal device may determine whether to select a four-stage RACH or a two-stage RACH based on the cell signal quality. In an embodiment of the present application, the cell signal quality may be represented by at least one of received signal code power (RSCP), reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR), signal to interference plus noise ratio (SINR), reference signal strength indication (RSSI), or other signal qualities. When the cell signal quality is represented by the reference signal received power, the quality threshold of the two-stage RACH may be the reference signal received power.

[0077] RSRP is used as an example. The terminal device obtains the RSRP by measuring a reference signal, and the quality threshold of the two-stage RACH is an RSRP value T. If the RSRP obtained by the terminal device through measurement is less than or equal to T, the terminal device selects the four-stage RACH, and if the RSRP obtained by the terminal device through measurement is greater than T, the terminal device selects the two-stage RACH.

[0078] (2) Four-step random access process

[0079] Refer to Figure 5. The NR system is used as an example, and the four-step random access process includes the following steps:

[0080] S1: The terminal device sends message 1 (MSG1).

[0081] It should be noted that message 1 includes a random access preamble. The terminal device receives at least one type of configuration information among four stages of RACH configuration information sent by the network device, such as preamble configuration information, RACH time-frequency resource configuration information, and maximum number of transmissions of the preamble. The preamble configuration information is used by the terminal device to determine the preamble. The RACH time-frequency resource configuration information is used by the terminal device to determine the RACH time-frequency resource. The RACH time-frequency resource is used by the terminal device to transmit the preamble.

[0082] For example, the terminal device initiates a contention-based four-step random access in a cell. The terminal device may select one preamble from the available preambles of the cell and transmit the preamble via a physical random access channel (PRACH). Alternatively, in a non-contention-based four-step random access, the terminal device transmits a preamble designated by the base station via the PRACH.

[0083] S2: After receiving the preamble sent by the terminal device, the base station sends a message 2 (MSG2) to the terminal device.

[0084] Note that message 2 may be referred to as a random access response (RAR).

[0085] After transmitting the preamble, the terminal device monitors a physical downlink control channel (PDCCH) within an RAR time window (RA response window) to receive a corresponding RAR.

[0086] In some possible implementations, after receiving the preamble transmitted by the terminal device, the base station estimates a transmission delay between the base station and the terminal device, and calculates an uplink timing advance (TA) based on the transmission delay, so that the base station calibrates the uplink timing. The base station further transmits the TA to the terminal device, so that the terminal device can perform uplink synchronization with the base station based on the TA.

[0087] In a possible implementation, the RAR includes at least one of a preamble identifier, TA information, and initial uplink grant (UL grant) information. Optionally, the RAR may further include a temporary identifier C-RNTI of the UE.

[0088] After receiving the RAR from the base station, the terminal device determines whether the preamble indicated by the preamble identifier in the RAR is the same as the preamble sent in step S1. If the preamble is the same, the RAR is deemed to be successfully received, otherwise, the reception of the RAR is deemed to be unsuccessful, and the terminal device may re-trigger the random access process.

[0089] Alternatively, if the terminal device does not receive the RAR returned by the base station within the RAR time window, the current random access process is deemed to have failed.

[0090] S3: The terminal device sends message 3 (MSG3) to the base station.

[0091] MSG3 includes the identity of the terminal device, which can be used for contention resolution in S4. The identity of the terminal device can be any one of the following: C-RNTI information of the terminal device, a resume ID or inactive RNTI (I-RNTI) of the terminal device, a system architecture evolution temporary mobile subscriber identity (S-TMSI), or a random number. The resume ID or I-RNTI is used by the base station to identify the terminal device associated with the context information, etc.

[0092] In some possible implementations, the terminal device may determine a physical uplink shared channel (PUSCH) based on the UL grant information in the RAR and transmit data via the PUSCH. The terminal device transmitting data via the PUSCH may be referred to as transmitting message 3.

[0093] The data transmitted by the terminal device via the PUSCH may include at least one of a radio resource control (RRC) layer message and user plane data of the terminal device.

[0094] S4: The base station sends message 4 (msg4) to the terminal device to resolve the contention.

[0095] Specifically, the base station may receive a message 3 sent by the terminal device and obtain the identity information of the terminal device from the message 3. The base station may send a message 4 to the terminal device to indicate the terminal device that won the random access contention, and another terminal device may resume random access. The message 4 may include a contention resolution identity (CR ID).

[0096] For example, the CR ID is the identification information of part or all of the terminal device in message 3. After receiving message 4, the terminal device compares the CR ID with the identification information of the terminal device in message 3. If the CR ID matches the identification information of the terminal device in message 3, the conflict resolution is successful. If the terminal device does not receive message 4, the terminal device may resume random access. Alternatively, if the CR ID does not match the identification information of the terminal device in message 3, that is, if the terminal device fails to resolve the conflict, the terminal device may resume random access.

[0097] (3) Two-step random access process

[0098] See Figure 6. The two-stage random access process includes the following steps:

[0099] A1: The terminal device sends a preamble and msgA.

[0100] Optionally, in some embodiments, the terminal device may only transmit msgA in A1. For example, if the TA of the terminal device is still valid or the cell radius is small, the terminal device may only transmit msgA in stage A1. The data transmitted by the terminal device through the PUSCH may include at least one of a radio resource control (RRC) layer message, an identification information of the terminal device, and user plane data. For the identification information of the terminal device, please refer to the related description above. Details will not be described again here.

[0101] It should be noted that before step A1, the terminal device receives configuration information sent by the base station. The configuration information may include two-stage random access configuration information and PUSCH configuration information. Optionally, the configuration information may further include a correspondence relationship between the two-stage random access configuration information and the PUSCH configuration information. The two-stage random access configuration information includes at least one of random access preamble configuration information and / or time-frequency resource configuration information. The random access preamble configuration information is used to determine a random access preamble, and the time-frequency resource configuration information is used to determine a time-frequency resource for transmitting the random access preamble.

[0102] For example, the two-stage random access configuration information includes preamble configuration information and PUSCH configuration information corresponding to the preamble. The preamble may have a one-to-one correspondence with the PUSCH, and multiple preambles correspond to one PUSCH, or one preamble corresponds to multiple PUSCHs.

[0103] Optionally, the configuration information may include the maximum number of transmissions of the preamble or msgA in two-stage random access.

[0104] A2: The terminal device receives msgB from the base station.

[0105] Specifically, msgB may include one or more RARs, where the RARs include a success response (success RAR) or a fallback response (fallback RAR). Optionally, msgB may hold indication information indicating whether the RAR in msgB is a success RAR or a fallback RAR.

[0106] The success RAR includes a contention resolution identifier. Optionally, the success RAR may indicate that the base station detects the preamble transmitted by the terminal device and successfully decodes the data transmitted via the PUSCH corresponding to the preamble. If the contention resolution is successful, the terminal device terminates the random access process. Otherwise, the terminal device may resume the random access.

[0107] The fallback RAR may indicate that the base station detects a preamble but fails to decode data transmitted through the PUSCH corresponding to the preamble, and that the terminal device does not win in the two-stage random access. Specifically, the fallback RAR may include at least one of a preamble identifier, TA information, and initial uplink grant information. After receiving the fallback RAR, the terminal device falls back to a four-stage random access mechanism. In other words, the terminal device may perform stage S3.

[0108] Optionally, step S4 may be further performed. If the contention resolution in step S4 fails, the terminal device initiates four-phase random access based on the four-phase random access configuration information, and performs step S1.

[0109] It can be understood that if the terminal device does not receive message B and the maximum transmission number of msgA has not been reached, the terminal device may resume the two-stage random access process.

[0110] (4) Two-stage random access fallback mechanism

[0111] The two-phase random access fallback involves two possible implementations:

[0112] In a possible implementation, if the number of initiations of the two-stage random access by the terminal device reaches a threshold (e.g., the maximum number of transmissions of the aforementioned msgA or random access preamble is reached) but the maximum number of accesses of cell connection failure is not reached, the terminal device may fall back to the four-stage random access. In an embodiment of the present application, this method may be referred to as active fallback.

[0113] In another possible implementation, the terminal device initiates a two-stage random access process. If the msgB received by the terminal device includes fallback RAR, the terminal device may fall back from the two-stage random access to the four-stage random access. In the embodiment of the present application, this method may be called passive fallback. In the prior art, the terminal device may record information in the four-stage random access process to generate a random access report (RACH report). After accessing the network device, the terminal device sends a RACH report to the network device. The RACH report may include the maximum number of preamble transmissions in the four-stage random access and whether a conflict is detected. Optionally, the RACH report may further include the carrier type of the cell in which the four-stage random access process is performed, for example, a normal uplink carrier or a supplementary uplink (SUL) carrier. The existing RACH report only supports a four-stage random access process and cannot support a two-stage random access process or a scenario in which the two-stage random access process falls back to a four-stage random access process. The network side cannot optimize the random access configuration based on the RACH report, which may result in the terminal device frequently falling back to the four-stage random access process, reducing the success rate of the random access of the terminal device.

[0114] An embodiment of the present application provides a communication method. A terminal device sends a first report to a first network device, and the first report includes first information. The first information indicates that the terminal device passively falls back from two-stage random access to four-stage random access, or actively falls back from two-stage random access to four-stage random access. The first network device receives the first report from the terminal device and performs processing based on the first report. In this embodiment of the present application, the network side adjusts corresponding configuration information according to the fallback method of the terminal device, thereby improving the success rate of random access of the terminal device and avoiding frequent two-stage random access fallback caused by improper configuration on the network side as much as possible. For example, when the first information indicates that the terminal device is performing active fallback, the two-stage random access configuration parameters may be adjusted to reduce the number of fallbacks of the terminal device. For example, the maximum number of transmissions of the random access preamble or msgA in the two-stage random access process is increased. The terminal device may attempt to transmit msgA multiple times to initiate the two-stage random access, thereby improving the success rate of the random access. Alternatively, when the first information indicates that the terminal device is performing passive fallback, the network side may adjust the time-frequency resources of the two-stage random access to allocate sufficient time-frequency resources to the terminal device for transmitting data related to the two-stage random access (e.g., msgA), thereby improving the success rate of the random access.

[0115] It may be understood that in the embodiments of the present application, the terminal device and / or the network device may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples. In the embodiments of the present application, other operations or variations of various operations may also be performed. In addition, the steps may be performed in a different order than the order presented in the embodiments of the present application, and all operations in the embodiments of the present application may not be performed.

[0116] The terminal device in the embodiment of the present application may be implemented using the communication device 710 in Fig. 7a. Fig. 7a is a schematic diagram of a hardware structure of the communication device 710 in the embodiment of the present application. The communication device 710 includes a processor 7101, a memory 7102, and at least one communication interface (here, Fig. 7a is only described using an example in which the communication device includes a communication interface 7103). The processor 7101, the memory 7102, and the communication interface 7103 are connected to each other. Optionally, the communication device 710 may not include the memory 7102.

[0117] The processor 7101 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to control the execution of programs in the solutions of the present application.

[0118] The communication interface 7103, using any device such as a transceiver, is configured to communicate with another device or a communication network, such as Ethernet, a radio access network (RAN), or a wireless local area network (WLAN).

[0119] The memory 7102 may be a read-only memory (ROM) or another type of static storage device capable of storing static information and instructions, or a random access memory (RAM) or another type of dynamic storage device capable of storing information and instructions, or may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or another optical disk storage device, an optical disk storage device (including compact optical disks, laser disks, optical disks, digital versatile optical disks, and Blu-ray disks, etc.), a magnetic disk storage medium or another magnetic storage device, or any other medium that can be used to hold or store expected program code in the form of instructions or data structures and that can be accessed by a computer. However, this is not a limitation herein. The memory may exist independently or may be connected to the processor. The memory may alternatively be integrated with the processor.

[0120] The memory 7102 is configured to store computer-executable instructions for executing the solution of the present application, and the processor 7101 controls the execution. The processor 7101 is configured to execute the computer-executable instructions stored in the memory 7102 to implement the communication methods provided in the following embodiments of the present application.

[0121] Optionally, the computer-executable instructions in this embodiment of the present application may also be referred to as application program code, which is not specifically limited in this embodiment of the present application.

[0122] During a particular implementation, in one embodiment, the processor 7101 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 7a.

[0123] During a particular implementation, in one embodiment, the communications device 710 may include multiple processors, such as, for example, processor 7101 and processor 7106 in FIG. 7a. Each of the processors may be a single-core (single-CPU) processor or a multi-core (multiple-CPU) processor, where a processor may be one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0124] During a particular implementation, in one embodiment, the communication apparatus 710 may further include an output device 7104 and an input device 7105. The output device 7104 is in communication with the processor 7101 and may display information in a number of ways. For example, the output device 7104 may be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 7105 is in communication with the processor 7101 and may receive input from a user in a number of ways. For example, the input device 7105 may be a mouse, a keyboard, a touch screen device, or a sensing device.

[0125] The communication device 710 may be a general-purpose device or a dedicated device. In a specific implementation, the communication device 710 may be a desktop computer, a portable computer, a network server, a palmtop computer (personal digital assistant, PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, or a device having a structure similar to that in FIG. 7a. The type of the communication device 710 is not limited in this embodiment of the present application.

[0126] It should be noted that the communication device 710 may be an entire terminal, a part or component implementing the function of the terminal, or a communication chip, such as a baseband chip. When the communication device 710 is an entire terminal, the communication interface may be a radio frequency module. When the communication device 710 is a communication chip, the communication interface 7103 may be an input / output interface circuit of the chip, where the input / output interface circuit is configured to read and output a baseband signal.

[0127] The network device in the embodiment of the present application may be implemented using the communication device 720 shown in Fig. 7b. For the structure of the communication device 720, please refer to the structure shown in Fig. 7b.

[0128] The communication device includes at least one processor 7201, at least one memory 7202, at least one transceiver 7203, at least one network interface 7204, and one or more antennas 7205. The processor 7201, the memory 7202, the transceiver 7203, and the network interface 7204 are connected, for example, via a bus. The antenna 7205 is connected to the transceiver 7203. The network interface 7204 is configured to allow the communication device to be connected to another communication device via a communication link. For example, the communication device is connected to a core network element via an S1 interface. In this embodiment of the present application, the connection may include various types of interfaces, transmission lines, or buses, etc. This is not limited in this embodiment. Optionally, the communication device 720 may not include a memory 7202.

[0129] In this embodiment of the present application, a processor such as the processor 7201 may include at least one of the following types: a general purpose central processing unit (CPU), a digital signal processor (DSP), a microprocessor, an application-specific integrated circuit (ASIC), a microcontroller unit (MCU), a field programmable gate array (FPGA), or an integrated circuit configured to implement logical operations. For example, the processor 7201 may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. At least one processor 7201 may be integrated into one chip or may be located on multiple different chips.

[0130] In this embodiment of the present application, a memory such as memory 7202 may include at least one of the following types: read-only memory (ROM) or another type of static storage device capable of storing static information and instructions, or random access memory (RAM) or another type of dynamic storage device capable of storing information and instructions, and may be an electrically erasable programmable read-only memory (EEPROM). In some scenarios, the memory may alternatively be a compact disc read-only memory (CD-ROM), another compact disc storage device, an optical disc storage device (including compressed optical discs, laser discs, optical discs, digital versatile discs, and Blu-ray discs, etc.), a magnetic disc storage medium, another magnetic storage device, or any other medium usable to hold or store expected program code in the form of instructions or data structures and accessible by a computer. This is not limited thereto.

[0131] The memory 7202 may exist independently or may be connected to the processor 7201. Optionally, the memory 7202 may alternatively be integrated with the processor 7201, for example, integrated into one chip. The memory 7202 may store program codes for implementing the technical solutions in the embodiments of the present application, and the processor 7201 controls the execution of the program codes. Various types of computer program codes to be executed may be regarded as drivers of the processor 7201. For example, the processor 7201 is configured to execute the computer program codes stored in the memory 7202 to implement the technical solutions in the embodiments of the present application.

[0132] The transceiver 7203 may be configured to support receiving or transmitting radio frequency signals between the communication apparatus and the terminal device, and the transceiver 7203 may be connected to an antenna 7205. Specifically, the one or more antennas 7205 may receive radio frequency signals. The transceiver 7203 may be configured to receive radio frequency signals from the antenna, convert the radio frequency signals to digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or digital intermediate frequency signals to the processor 7201, so that the processor 7201 further processes the digital baseband signals or digital intermediate frequency signals, for example, performing demodulation and decoding processes. In addition, the transceiver 7203 may be configured to receive modulated digital baseband signals or digital intermediate frequency signals from the processor 7201, convert the modulated digital baseband signals or digital intermediate frequency signals to radio frequency signals, and transmit the radio frequency signals via the one or more antennas 7205. Specifically, the transceiver 7203 may selectively perform one or more levels of frequency downmix processing and analog-to-digital conversion processing on the radio frequency signal to obtain a digital baseband signal or a digital intermediate frequency signal. The order of the frequency downmix processing and the analog-to-digital conversion processing is adjustable. The transceiver 7203 may selectively perform one or more levels of frequency upmix processing and digital-to-analog conversion processing on the modulated digital baseband signal or the digital intermediate frequency signal to obtain a radio frequency signal. The order of the frequency upmix processing and the digital-to-analog conversion processing is adjustable. The digital baseband signal and the digital intermediate frequency signal may be generally referred to as a digital signal. The transceiver may be referred to as a transceiver circuit, a transceiver unit, a transceiver component, a transmission circuit, a transmission unit, a transmission component, or the like.

[0133] It should be noted that the communication device 720 may be an entire communication device, a part or component that implements the functionality of a communication device, or may be a communication chip. If the communication device 720 is a communication chip, the transceiver 7203 may be an interface circuit of the chip, where the interface circuit is configured to read and output a baseband signal.

[0134] An embodiment of the present application provides a communication method. As shown in Figure 8, the method includes the following steps:

[0135] 801: A terminal device sends a first report to a first network device, where the first report includes first information.

[0136] The first information indicates that the terminal device passively falls back from two-stage random access to four-stage random access, or actively falls back from two-stage random access to four-stage random access.

[0137] Alternatively, the first information indicates a manner in which the terminal device falls back from two-stage random access to four-stage random access. The fallback manner of the terminal device may be a passive fallback or an active fallback.

[0138] Alternatively, the first information indicates whether the terminal device falls back from two-stage random access to four-stage random access, or the first information indicates whether the terminal device receives a fallback instruction, such as the aforementioned fallback RAR or RAR type instruction information.

[0139] In a possible implementation, the terminal device sends a first message to the first network device, where the first message includes a first report, and the first report includes first information. The first message can be a user equipment information response message, an RRC reconfiguration response message, or an RRC connection reconfiguration response message. The first report can be a report related to random access and reported by the terminal device to the first network device, such as a RACH report, a setup failure report, a resumption failure report, a radio link failure report, or a handover success report.

[0140] It should be noted that when the terminal device initiates two-stage random access and falls back to four-stage random access in the first cell, the terminal device may generate a first report to record when the terminal device performs random access in the first cell. The network device to which the first cell belongs may be referred to as the network device corresponding to the first report.

[0141] In this embodiment of the present application, the first network device is the network device to which the cell in which the terminal device currently exists belongs. The first network device may be the same network device as the network device corresponding to the first report, or may be a different network device from the network device corresponding to the first report.

[0142] For example, a terminal device initiates a two-stage random access and falls back to a four-stage random access in a cell of a first network device. The terminal device may generate a first report by recording information related to the random access and send the first report to the first network device, so that the first network device can optimize two-stage random access configuration parameters of the terminal device based on the information (e.g., the first information) in the first report, and the terminal device prevents frequent fallback to four-stage random access as much as possible, thereby improving the success rate of the random access.

[0143] Alternatively, the terminal device may initiate random access in a cell of a second network device (different from the first network device), record information related to the random access, and generate a first report. When the terminal device moves to the cell of the first network device, the terminal device may transmit the first report to the first network device, and the first network device may transmit all or part of the information in the first report to the second network device (e.g., determine the second network device corresponding to the first report based on the cell information in the first report), so that the second network device optimizes the two-stage random access configuration parameters of the terminal device based on the information in the first report (e.g., the first information).

[0144] In a possible implementation, the first information is one bit, and the one bit is a first value or a second value. When the one bit is the first value, it indicates an active falloff. Specifically, the terminal device actively falls back from two-stage random access to four-stage random access. When the one bit is the second value, it indicates a passive falloff. Specifically, the terminal device passively falls back from two-stage random access to four-stage random access.

[0145] For example, the first value is "0" and the second value is "1", or the first value is "1" and the second value is "0".

[0146] Optionally, the first report may include second information, the second information indicating a quality threshold of two-stage random access, the second information being used by the network device to determine whether a quality threshold of two-stage random access configured for the terminal device is appropriate.

[0147] For example, the terminal device measures the signal quality to obtain a measurement result, and compares the measurement result with a quality threshold of the two-stage random access to select whether to perform the four-stage random access or the two-stage random access. The signal quality can be represented by at least one of received signal code power (RSCP), reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR), signal to interference plus noise ratio (SINR), reference signal strength indication (RSSI) or other signal qualities. Accordingly, the representations of different signal qualities also have corresponding quality thresholds.

[0148] Optionally, the first report may include third information, which is used by the network device to determine two-stage random access configuration information used when the terminal device falls back from two-stage random access to four-stage random access. The third information includes at least one of the following information: physical uplink shared channel PUSCH configuration information configured for the terminal device in two-stage random access, random access configuration information in two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH configuration information. The third information may be obtained by the terminal device from a system message or from a dedicated signal.

[0149] The random access configuration information includes at least one of random access preamble configuration information and / or time-frequency resource configuration information, where the random access preamble configuration information is used to determine a random access preamble, and the time-frequency resource configuration information is used to determine a time-frequency resource for transmitting the random access preamble.

[0150] Optionally, the first report may include fourth information, and the fourth information is used by the network device to determine time information for the terminal device to fall back from two-stage random access to four-stage random access. The time information may indicate a time point, a time length, a relative time point, or a time deviation. The time point refers to a specific time. For example, the time information may be the time point when two-stage random access is initiated, the time point when the terminal device sends MSG1, the time point when the terminal device receives two-stage random access configuration information, the time point when the terminal device performs two-stage random access, or the time point when the terminal device starts four-stage random access after two-stage random access fails. This is not limited in this embodiment of the present application.

[0151] The time length is used as an example. The fourth information may be a time length that exists after "the terminal device receives the two-stage random access configuration information". For example, the time information is a time length between the time when "the terminal device receives the two-stage random access configuration information" and the time when "the terminal device reports the first report".

[0152] Alternatively, the fourth information may be a time length that exists after the terminal device falls back to the four-stage random access. For example, the time information is a time length between the time when the terminal device falls back from the two-stage random access to the four-stage random access and the time when the terminal device reports the first report.

[0153] Optionally, the first report may include fifth information, where the fifth information indicates a first cell where the terminal device performs two-stage random access. The first cell is a cell where the terminal device fails to initiate two-stage random access and falls back to four-stage random access, or the first cell is a cell corresponding to the first report recorded by the terminal device. The fifth information may include at least one of the following cell information: a cell global identifier (CGI), a physical cell identifier (PCI) and frequency information of the cell, and a cell identifier.

[0154] In a possible implementation, the fifth information may indicate whether the first report is a report corresponding to a cell of a secondary node.

[0155] For example, in the scenario shown in Figure 2, the terminal device may initiate random access (e.g., two-stage random access) in the cell of the master node MN. After the two-stage random access performed in the cell of the master node fails, the terminal device may fall back to four-stage random access. If the terminal device successfully performs random access in the cell of the MN, the terminal device may send a first report to the master network device (e.g., the first network device in this embodiment of the present application) to which the cell of the MN belongs, to indicate information related to the two-stage random access performed in the cell of the master node.

[0156] In addition, if a secondary node SN is added or changed, the terminal device may initiate random access in a cell of the new SN. In a possible implementation, after the two-stage random access performed by the terminal device in the cell of the secondary node fails, the terminal device may fall back to four-stage random access. The terminal device may send a first report to the master network device to indicate information related to the two-stage random access performed in the cell of the secondary node. The first report may further include fifth information. For example, the fifth information may be cell information of the secondary node, or the fifth information may indicate whether the first report is a report corresponding to the cell of the secondary node.

[0157] Optionally, the first report may include sixth information, where the sixth information indicates at least one of the following information: a network type of the first cell, a frequency type of the first cell, a service type of the first cell, and a type of the first cell, where the first cell is a cell in which the terminal device performs two-stage random access.

[0158] Network types may include a public network, a non-public network (NPN), a standalone non-public network (SNPN), a non-standalone non-public network (e.g., a public network integrated NPN (PNI-NPN)), or a closed access group (CAG).

[0159] The frequency type may include a carrier type of the first cell, for example, an NR UL, a supplemental uplink carrier, or an unlicensed band cell.

[0160] The service type is a type of service applied in the first cell by the terminal device. The service type may include mobile broadband (MBB), enhanced mobile broadband (eMBB), industrial internet of things (IIoT), ultra-reliable and low-latency communication (URLLC), Internet of Things (machine-type communication (MTC), massive machine-type communications (mMTC), narrowband Internet of Things (NB-IoT), augmented reality (AR), virtual reality (VR), or another service type.

[0161] The type of the first cell may include at least one of the following types: a non-terrestrial network (NTN) cell, a terrestrial cell, a low earth orbit (LEO) satellite cell, a geostationary earth orbit (GEO) satellite cell, a low earth orbit regenerative cell, and a low earth orbit transparent transmission cell, etc.

[0162] In a possible implementation, the first report may include seventh information, and the seventh information indicates at least one of the following information: the maximum transmission number of the random access preamble or msgA in the two-stage random access, whether the terminal device detects a conflict in the two-stage random access, whether the maximum transmission power of the terminal device is reached, and the actual number of times the random access preamble is transmitted by the terminal device in the two-stage random access. The actual number of transmissions is less than or equal to the maximum transmission number of the random access preamble or msgA. For example, if the terminal device receives msgB, but the CR ID in msgB is different from the CR ID of the terminal device, it indicates that the terminal device detects a conflict.

[0163] In a possible implementation, the first report may include eighth information, and the eighth information may indicate at least one of the following information: the maximum number of transmissions of the random access preamble in the four-stage random access, whether the terminal device detects a conflict in the four-stage random access, whether the maximum transmission power of the terminal device is reached, and the actual number of times the random access preamble is transmitted by the terminal device in the four-stage random access. The actual number of transmissions is less than or equal to the maximum number of transmissions of the random access preamble. For example, if the terminal device receives msg4 but the identifier in msg4 is different from the identifier of the terminal device, it indicates that the terminal device detects a conflict.

[0164] In a possible implementation, the terminal device also uses different messages to transmit one or more of the first information to the eighth information to the first network device. It can be understood that the terminal device uses N messages to transmit one or more of the first information to the eighth information to the first network device, where N is a positive integer smaller than 8. For example, one message may carry two pieces of information, or may carry more information. This is not limited in the present specification.

[0165] It may be understood that the first report may include one or more of the first information to the eighth information.

[0166] 802: The first network device receives a first report from the terminal device and performs an action based on the first report.

[0167] In some possible implementations, the first network device receives the first report sent by the terminal device, and performs corresponding processing based on the first report.

[0168] For example, the first network device obtains a first report from the first message, and if the first network device is a network device corresponding to the first report, the first network device may optimize two-stage random access parameters configured for the terminal device based on the first report to improve the success rate of the random access of the terminal device.

[0169] For another example, when the first network device determines that the second network device is a network device corresponding to the first report, the first network device transmits part or all of the information in the first report to the second network device, so that the second network device can optimize the two-stage random access parameters configured for the terminal device based on part or all of the information in the first report to improve the success rate of the random access. Optionally, the first network device may further transmit type information of the first report. The type of the first report may be pure 5G (e.g., NR or gNB), 4G connected to a 5G core network (e.g., eLTE or ng-eNB), or pure 4G (e.g., LTE or eNB). Optionally, the second network device may determine an encoding format of the first report based on the type information of the first report and perform corresponding decoding.

[0170] In a possible implementation, the first network device is a centralized unit CU, and the second network device is a distributed unit DU. The first network device transmits part or all of the information in the first report to the second network device via an F1 interface. Optionally, the first network device may further transmit type information of the first report to the second network device.

[0171] In another possible implementation, the first network device and the second network device are different base stations. The first network device may directly or indirectly transmit part or all of the information in the first report to the second network device. Optionally, the first network device may further transmit type information of the first report to the second network device. For example, if there is an interface that can be directly used for communication between the first network device and the second network device, the first network device transmits part or all of the information in the first report to the second network device via an interface between base stations. The interface between the first network device and the second network device may be an X2 interface or an Xn interface. Optionally, part or all of the information in the first report may be transmitted to the second network device using a failure indication (FAILURE INDICATION, RLF INDICATION) message or a handover report (HANDOVER REPORT) message.

[0172] When the first network device and the second network device cannot directly communicate with each other, the first network device may transmit part or all of the information in the first report to the second network device via another device (e.g., a core network device). Optionally, the first network device may further transmit type information of the first report to the second network device. For example, part or all of the information in the first report is transmitted to the core network device via an interface between the base station and the core network device. Optionally, the first network device transmits part or all of the information in the first report to the core network device via an S1 or NG interface, and the core network device forwards the information received from the first network device to the second network device. The first network device may send some or all of the information in the first report to the second network device using the following messages on the S1 / NG interface: UPLINK RAN CONFIGURATION TRANSFER message, DOWNLINK RAN CONFIGURATION TRANSFER message, eNB CONFIGURATION TRANSFER message, or MME CONFIGURATION TRANSFER message.

[0173] In another possible implementation, the first network device is a CU, and the second network device is a base station. For example, the first base station includes a CU and a DU. The terminal device may send a first report to the CU, and the CU may send some or all of the information in the first report to the second base station.

[0174] Alternatively, the first network device is a base station and the second network device is a CU. For example, the second base station includes a CU and a DU. The terminal device may send a first report to the first base station, and the first base station may send some or all of the information in the first report to the CU.

[0175] The following describes, with reference to specific information, an optimization process that may be performed by a network device (for example, the first network device or the second network device in this embodiment of the present application) based on the first report.

[0176] When the first report includes the first information, and the first information indicates that the terminal device performs active fallback, the network device may reduce the number of fallbacks of the terminal device by adjusting two-stage random access configuration parameters. For example, the maximum number of transmissions of the random access preamble or msgA in the two-stage random access process is increased. The terminal device may attempt to transmit msgA multiple times to initiate the two-stage random access, so that the success rate of the random access may be improved.

[0177] Alternatively, when the first information indicates that the terminal device is performing passive fallback, the network side may adjust the time-frequency resources of the two-stage random access to allocate sufficient time-frequency resources to the terminal device for transmitting data related to the two-stage random access (e.g., msgA), thereby improving the success rate of the random access.

[0178] When the first report includes the second information, the network device may increase the quality threshold of the two-stage random access, so that the terminal device selects the four-stage random access as much as possible. To some extent, the terminal device is prevented from frequently falling back to the four-stage random access process, thereby improving the success rate of the random access of the terminal device.

[0179] If the first report includes the third information, the network device may determine, based on the third information, a PUSCH through which the terminal device transmits data in two-stage random access, and may adjust the time-frequency resource of the PUSCH to avoid, as much as possible, two-stage random access failure of the terminal device caused by insufficient time-frequency resource of the PUSCH.

[0180] Alternatively, the second network device may determine a time-frequency resource of the random access preamble or adjust the time-frequency resource of the random access preamble based on the third information, so as to avoid random access failure of the terminal device caused by insufficient time-frequency resource for transmitting the random access preamble as much as possible.

[0181] Alternatively, the second network device may determine a correspondence between the random access configuration information and the PUSCH based on the third information, and adjust the correspondence. For example, one two-stage random access preamble may correspond to more PUSCHs to avoid two-stage random access failure of the terminal device caused by insufficient time-frequency resources of the PUSCH. Alternatively, more two-stage random access resources and corresponding PUSCHs may be assigned.

[0182] If the first report includes the fourth information, the network device determines, based on the time information indicated by the fourth information, the two-stage random access configuration information that causes the current two-stage random access fallback, thereby adjusting the two-stage random access configuration information, thereby improving the success rate of the terminal device's execution of the two-stage random access. In this way, the terminal device is prevented to a certain extent from frequently falling back to the four-stage random access.

[0183] If the first report includes the fifth information, the network device may determine a network device corresponding to the first report based on the fifth information, and forward some or all of the information in the first report to the network device. For example, the first network device may determine a network device corresponding to the first report, such as the second network device in this embodiment of the present application, by determining a cell corresponding to the first report based on the fifth information. The first network device may forward some or all of the information in the first report to the second network device, for example, forward one or more of the first information to the eighth information to the second network device.

[0184] When the first report includes the sixth information, the network device may determine characteristics of a cell in which the terminal device performs the two-stage random access, and optimize the two-stage random access configuration information based on the characteristics of the cell to improve the success rate of the random access of the terminal device. The characteristics of the cell may be one or more of a network type, a frequency type, or a service type of the cell.

[0185] For example, the two-stage random access parameters are optimized based on the network type of the first cell, and the degree of matching between the optimized parameters and the network type of the first cell is improved. This helps to improve the success rate of the random access performed by the terminal device in the first cell. The two-stage random access parameters are optimized based on the service type of the first cell, and the degree of matching between the optimized parameters and the network type of the first cell is improved. For example, the optimized parameters are more suitable for the requirements of the NPN network. This helps to improve the success rate of the random access performed by the terminal device in the first cell.

[0186] When the first report includes the seventh information, the network device may adjust the maximum transmission times of the two-stage random access preamble or msgA, so that the terminal device attempts to send the random access preamble multiple times to initiate the two-stage random access, which helps to improve the success rate of the terminal device in the first cell to perform the two-stage random access.

[0187] When the first report includes the eighth information, the network device may adjust a four-stage random access configuration parameter, such as a maximum number of transmissions of the four-stage random access preamble, which helps to improve the success rate of the execution of the four-stage random access by the terminal device in the first cell.

[0188] In the method shown in Figure 8, the terminal device actively reports information related to random access fallback to the network device. Differently, an embodiment of the present application further provides a communication method in which the terminal device may further indicate a reporting requirement of the terminal device to the network device before recording and reporting information related to random access fallback, and the terminal device reports information related to random access falloff only after the network device instructs the terminal device to report information related to random access fallback. As shown in Figure 9, the method includes the following steps.

[0189] 901: A terminal device transmits capability information to a network device.

[0190] The capability information indicates that the terminal device supports recording of reports related to two-phase random access, or that the terminal device supports recording of reports of fallback from two-phase random access to four-phase random access.

[0191] 902: The terminal device determines that a fallback from two-phase random access to four-phase random access has occurred.

[0192] In some possible implementations, the terminal device receives two-stage random access configuration information or four-stage random access configuration information, and selects whether to perform two-stage random access based on the signal quality obtained through measurement. For the procedure of performing two-stage random access by the terminal device, please refer to Figure 6 and the above related description of Figure 6. Details will not be described again here.

[0193] The terminal device may further fall back to four-stage random access. In a possible implementation, the terminal device receives a fallback instruction (e.g., fallback RAR) sent by the network device and passively falls back to four-stage random access.

[0194] In another possible implementation, when it is determined that the two-phase random access has failed, the terminal device actively falls back to the four-phase random access. For example, when the number of times that the terminal device transmits the random access preamble or msgA in the two-phase random access reaches the maximum number of transmissions of the random access preamble, the terminal device determines that the two-phase random access has failed. Alternatively, when the terminal device receives msgB but the CR ID in msgB is different from the CR ID of the terminal device, it is determined that the two-phase random access has failed. In a specific implementation, please refer to FIG. 5 and the above related description of FIG. 5 for the procedure of the four-phase random access performed by the terminal device. Details will not be described again here.

[0195] 903: The terminal device generates a first report.

[0196] Optionally, the terminal device may receive indication information sent by the network device and used to indicate whether the terminal device has recorded the first report. The terminal device may determine whether to generate the first report based on the indication information.

[0197] The first report is used to record information related to the two-stage random access performed by the terminal device, for example, the first report includes one or more of the first information to the eighth information in this embodiment of the present application.

[0198] 904: The terminal device sends first indication information to the network device.

[0199] The first indication information indicates that the terminal device needs to send a report related to the two-stage random access, such as the first report in this embodiment of the present application, to the network device.

[0200] In an example, the terminal device may send the first indication information to the network device using any one of an RRC connection setup complete message, an RRC connection resume request message, an RRC connection resume complete message, an RRC connection reconfiguration complete message, an RRC setup complete message, an RRC resume request message, an RRC resume complete message, and an RRC reconfiguration complete message.

[0201] 905: The network device sends second indication information to the terminal device.

[0202] The second indication information indicates that the terminal device sends a report related to two-stage random access, such as the first report in this embodiment of the present application.

[0203] For example, the network device may send the second indication information to the terminal device using any one of a terminal device information request message, an RRC connection reconfiguration message, and an RRC reconfiguration message.

[0204] 906: The terminal device sends a first report to the network device.

[0205] 907: The network device receives the first report and performs an action based on the first report.

[0206] It can be understood that the network devices in the above steps are used in a general sense. In other words, the network devices in all steps may be the same or different. For detailed descriptions of step 906 and step 907, please refer to the descriptions of step 801 and step 802, respectively. The details will not be described again here.

[0207] In this scenario, the order of steps 901, 902, and 903 is not limited. Step 902 may be performed first, followed by steps 901 and 903. Alternatively, steps 902 and 903 may be performed first, followed by step 901. In some implementations, step 901 is optional. Step 901 may be ignored and steps 902 to 907 may be performed.

[0208] In another possible implementation, after performing random access fallback in the cell of the network device, the terminal device may further send a report related to the two-stage random access to another network device. In step 907, the network device may determine a network device corresponding to the first report based on the information in the first report, and send part or all of the information in the first report to the network device corresponding to the first report, so that the network device corresponding to the first report can optimize the two-stage random access configuration parameters based on the received information. In this way, the terminal device is prevented from frequently falling back to four-stage random access, and the success rate of the random access of the terminal device is improved.

[0209] In this scenario, steps 902 and 903 are executed first, followed by step 901.

[0210] Please note that the steps in the procedure shown in FIG. 9 are not necessary steps to implement the communication method provided in this embodiment of the present application, and only some of those steps may be performed to implement the communication method.

[0211] In a possible implementation, the network device may instruct the terminal device to report information related to random access fallback. After receiving the instruction from the network device, the terminal device reports the information related to random access fallback. For example, the network device sends third instruction information to the terminal device, where the third instruction information instructs the terminal device to report information about random access fallback. After receiving the third instruction information, the terminal device reports a first report to the network device, where the first report includes information and a specific description of each piece of information. For details, please refer to the above description. For details, the description will not be given here.

[0212] In the communication system shown in FIG. 2, in a scenario in which the network device instructs the terminal device to add a secondary cell SN, the terminal device may initiate random access to the added secondary cell, and a fallback from two-stage random access to four-stage random access may occur. In a scenario in which the network device instructs the terminal device to update the secondary cell SN, the terminal device may initiate random access to the updated secondary cell, and a fallback from two-stage random access to four-stage random access may occur. In the above two scenarios, the terminal device may report information related to random access fallback to the primary cell MN, so that the network device to which the primary cell MN belongs (e.g., the base station to which the primary cell MN belongs) optimizes random access configuration parameters to improve the success rate of the execution of random access by the terminal device in the secondary cell. The embodiment of the present application further provides a communication method for supporting the terminal device in the step of reporting information related to random access fallback in the above scenario. As shown in FIG. 10, the method includes the following steps.

[0213] 1001: A network device to which a primary cell belongs sends fourth indication information to a terminal device.

[0214] The fourth indication information is used to instruct the terminal device to add or update the secondary cell.

[0215] 1002: The terminal device receives fourth indication information and initiates a procedure for adding a secondary cell or a procedure for updating a secondary cell.

[0216] 1003: The terminal device determines that a fallback from two-phase random access to four-phase random access has occurred.

[0217] In some possible implementations, the terminal device initiates a two-stage random access in the procedure of adding a secondary cell or updating a secondary cell. The addition of a secondary cell is used as an example. After receiving SN reconfiguration complete from the primary cell, the terminal device initiates random access in the secondary cell.

[0218] In some possible implementations, the terminal device receives two-stage random access configuration information or four-stage random access configuration information, and selects whether to perform two-stage random access based on the signal quality obtained through measurement. For the procedure of performing two-stage random access by the terminal device, please refer to Figure 6 and the above related description of Figure 6. Details will not be described again here.

[0219] The terminal device may further fall back to four-stage random access. In a possible implementation, the terminal device receives a fallback instruction (e.g., fallback RAR) sent by the network device and passively falls back to four-stage random access.

[0220] In another possible implementation, when it is determined that the two-phase random access has failed, the terminal device actively falls back to the four-phase random access. For example, when the number of times that the terminal device transmits the random access preamble or msgA in the two-phase random access reaches the maximum number of transmissions of the random access preamble, the terminal device determines that the two-phase random access has failed. Alternatively, when the terminal device receives msgB but the CR ID in msgB is different from the CR ID of the terminal device, it is determined that the two-phase random access has failed. In a specific implementation, please refer to FIG. 5 and the above related description of FIG. 5 for the procedure of the four-phase random access performed by the terminal device. Details will not be described again here.

[0221] 1004: The terminal device generates a first report.

[0222] The first report is used to record information related to the random access performed by the terminal device. For example, the first report includes one or more of the first information to the eighth information in this embodiment of the present application.

[0223] 1005: The terminal device sends a first report to a network device to which the primary cell belongs.

[0224] 1006: The network device to which the primary cell belongs receives the first report, and performs an action based on the first report.

[0225] For example, the network device for which the primary cell is executed may transmit some or all of the information in the first report to the network device to which the secondary cell belongs, so that the network device to which the secondary cell belongs determines configuration parameters for performing random access by the terminal device in the secondary cell based on the received information, and optimizes the configuration parameters to improve the success rate of performing random access by the terminal device in the secondary cell.

[0226] It should be noted that steps 1005 and 1006 are optional steps, and steps 1005 and 1006 may not be executed. After steps 1001 to 1004 are executed, the terminal device may further transmit a first report to a network device to which the secondary cell belongs, and the network device to which the secondary cell belongs may determine configuration parameters for the execution of random access by the terminal device in the secondary cell based on the information in the first report, and optimize the configuration parameters to improve the success rate of the execution of random access by the terminal device in the secondary cell.

[0227] It should be noted that the steps in the procedure shown in FIG. 10 are not necessary steps to implement the communication method provided in this embodiment of the present application, and only some of those steps may be performed to implement the communication method.

[0228] When each functional module is obtained through division based on each corresponding function, FIG. 11 is a schematic diagram of a possible structure of a communication device in the aforementioned embodiment. The communication device shown in FIG. 11 may be a terminal device described in the embodiment of the present application, or may be a component implementing the aforementioned method in a terminal device, or may be a chip used in a terminal device. The chip may be a System-On-a-Chip (SOC), or a baseband chip with communication function, etc. As shown in FIG. 11, the communication device includes a processing unit 1101 and a communication unit 1102. The processing unit may be one or more processors, and the communication unit may be a transceiver or a communication interface.

[0229] For example, the processing unit 1101 may be configured to support a terminal device in performing steps 902 and 903 or steps 1002 and 1004, and / or may be configured to perform another process of the techniques described herein.

[0230] The communication unit 1102 may be configured to support communication between a terminal device and another communication apparatus, for example, to support the terminal device in performing one or more of steps 801, 901, 904 to 906, 1002, and 1005, and / or to perform other processes of the techniques described herein.

[0231] It should be noted that all relevant contents of the steps in the above method embodiments can be cited in the functional description of the corresponding functional modules, and the details will not be described again here.

[0232] As shown in FIG. 12, the communications device may further include a storage unit 1103, configured to store program codes and / or data of the communications device.

[0233] The processing unit 1101 may include at least one processor. The communication unit 1102 may be a transceiver or a communication interface, and the storage unit 1103 may include a memory.

[0234] When each functional module is obtained through division based on each corresponding function, FIG. 13 is a schematic diagram of a possible structure of a communication device in the aforementioned embodiment. The communication device shown in FIG. 13 may be the first network device described in the embodiment of the present application, or may be a component implementing the aforementioned method in the network device, or may be a chip used in the network device. The chip may be a System-On-a-Chip (SOC), or a baseband chip with communication function, etc. As shown in FIG. 13, the communication device includes a processing unit 1201 and a communication unit 1202. The processing unit 1201 may be one or more processors, and the communication unit 1202 may be a transceiver or a communication interface.

[0235] The processing unit 1201 is configured to support the network device in performing steps 801, 907, and 1006, and / or to perform other processes of the techniques described herein.

[0236] The communications unit 1202 is configured to support communications between the network device and another communications apparatus, e.g., to support the network device in performing steps 802, 901, 904 to 906, 1001, and 1005, and / or to perform other processes of the techniques described herein.

[0237] It should be noted that all relevant contents of the steps in the above method embodiments can be cited in the functional description of the corresponding functional modules, and the details will not be described again here.

[0238] As shown in FIG. 14, the communications device may further include a memory unit 1203, configured to store program codes and data of the communications device.

[0239] The processing unit 1201 may include at least one processor. The communication unit 1202 may be a transceiver or a communication interface, and the storage unit 1203 may include at least one memory.

[0240] For the structure of the second network device in the embodiment of the present application, please refer to Figure 13 or Figure 14. The communication unit 1202 is configured to support communication between the second network device and another device, for example, to support the second network device in receiving part or all of the information in the first report sent by the first network device. The processing unit 1201 is configured to support the second network device in performing processing based on part or all of the information in the received first report, for example, optimizing random access configuration parameters based on part or all of the information in the first report, so as to improve the success rate of random access of the terminal device.

[0241] It should be noted that in the above-described communication device embodiments, each unit may be referred to as a module, a component, a circuit, or the like accordingly.

[0242] An embodiment of the present application provides a computer-readable storage medium, which stores instructions, which are used to perform the method shown in FIG.

[0243] An embodiment of the present application provides a computer program product including instructions, which, when executed on a communication device, enable the communication device to perform the method illustrated in FIG.

[0244] An embodiment of the present application provides a wireless communication device, which stores instructions, and when the instructions are executed on the communication device shown in Figure 7a, Figure 7b and Figure 11 to Figure 14, the communication device can execute the method shown in Figure 8, Figure 9 or Figure 10. The wireless communication device can be a chip.

[0245] The embodiment of the present application further provides a communication system including a terminal device and a network device. For example, the terminal device may be the communication device shown in Figure 7a, Figure 11 or Figure 12, and the network device may be the communication device shown in Figure 7b, Figure 13 or Figure 14.

[0246] From the above description of the implementation, those skilled in the art can understand that for convenience and simplicity of description, the above division of functional modules is used as an example for explanation. During practical application, the above functions can be allocated to different functional modules and implemented based on requirements, that is, the internal structure of the communication device is divided into different functional modules to implement all or part of the above functions.

[0247] The processor in this embodiment of the present application may include, but is not limited to, at least one of the following various computing devices that execute software: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor. Each computing device may include one or more cores configured to perform an operation or process by executing software instructions. The processor may be an independent semiconductor chip, or may be integrated with another circuit to form a semiconductor chip. For example, the processor may form a SoC (system on chip) with another circuit (e.g., encoding / decoding circuit, hardware acceleration circuit, or various bus and interface circuits). Alternatively, the processor may be integrated into an ASIC as an embedded processor of the ASIC, and the ASIC integrated with the processor may be packaged independently or together with another circuit. A processor includes a core configured to perform operations or processes by executing software instructions, and may further include necessary hardware accelerators, such as a field programmable gate array (FPGA), a programmable logic device (PLD), or logic circuitry that implements application-specific logic operations.

[0248] In this embodiment of the present application, the memory may include at least one of the following types: read-only memory (ROM) or another type of static storage device capable of storing static information and instructions, or random access memory (RAM) or another type of dynamic storage device capable of storing information and instructions, and may be electrically erasable programmable read-only memory (EEPROM). In some scenarios, the memory may alternatively be a compact disc read-only memory (CD-ROM), another compact disc storage device, an optical disc storage device (including compressed optical discs, laser discs, optical discs, digital versatile discs, and Blu-ray discs, etc.), a magnetic disc storage medium, another magnetic storage device, or any other medium usable to hold or store expected program code in the form of instructions or data structures and accessible by a computer. This is not limited thereto.

[0249] In this application, "at least one" means one or more. "multiple" means two or more than two. The term "and / or" describes a correspondence between associated objects and indicates that three relationships may exist. For example, A and / or B may represent the presence of only A, the presence of both A and B, or the presence of only B, where A and B may be singular or plural. Typically, the symbol " / " indicates an "or" relationship between associated objects. "At least one of the following items" or similar expressions refers to any combination of the items, including any combination of singular items or multiple items. For example, at least one of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural. In addition, for the convenience of clearly describing the technical solutions in the embodiments of the present application, terms such as "first" and "second" are used in the embodiments of the present application to distinguish between the same objects or similar objects whose functions and purposes are basically the same. Those skilled in the art can understand that terms such as "first" and "second" do not constitute limitations on the number or execution order, and terms such as "first" and "second" do not indicate clear differences.

[0250] In some embodiments provided in the present application, it should be understood that the disclosed database access apparatus and method may be implemented in other ways. For example, the described embodiment of the database access apparatus is merely an example. For example, the division of modules or units is merely a division of logical functions, and may be other divisions during actual implementation. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not performed. In addition, the shown or described mutual couplings, or direct couplings or communication connections may be implemented through some interfaces. Indirect couplings or communication connections between database access apparatuses or units may be implemented in electronic, mechanical, or other forms.

[0251] The units described as separate parts may or may not be physically separate, and the parts shown as units may be one or more physical units, or may be located in one place or distributed in different places. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0252] In addition, the functional units in the embodiments of the present application may be integrated into one processing unit, or each of the units may exist physically alone, or two or more units may be integrated into one unit. The integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0253] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially implemented in the form of a software product, or the part that contributes to the prior art, or all or part of the technical solutions may be implemented in the form of a software product. The software product is stored in a storage medium and includes some instructions that instruct a device (which may be a single-chip microcomputer, or a chip, etc.) or a processor to perform all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0254] The above description is merely a specific implementation example of the present application, and is not intended to limit the protection scope of the present application. Any modifications or replacements within the technical scope disclosed in the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims. [Other possible items] [Item 1] receiving, by a first network device, a first report from a terminal device, the first report having first information, the first information indicating that the terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access; performing an action based on the first report by the first network device; A communication method comprising: [Item 2] 2. The method of claim 1, wherein the first report further includes second information, the second information indicating two-stage random access quality thresholds. [Item 3] The method according to item 1 or 2, wherein the first report further comprises third information, and the third information comprises at least one of the following information: information about a physical uplink shared channel (PUSCH) configured for the terminal device in two-stage random access, random access configuration information in two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH. [Item 4] 4. The method according to any one of claims 1 to 3, wherein the first report further comprises fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access. [Item 5] 5. The method according to any one of claims 1 to 4, wherein the first report further comprises fifth information, and the fifth information indicates cell information for the terminal device to perform two-stage random access. [Item 6] The first report further comprises sixth information, the sixth information indicating at least one of the following information: a network type of the first cell, a frequency type of the first cell, a service type of the first cell, and a type of the first cell; 6. The method according to any one of claims 1 to 5, wherein the first cell is a cell in which the terminal device performs two-stage random access. [Item 7] The step of the first network device performing an action based on the first report includes: 7. The method of any one of claims 1 to 6, comprising the first network device transmitting some or all of the information in the first report to a second network device. [Item 8] The first network device is a centralized unit CU and the second network device is a distributed unit DU, or 8. The method of claim 7, wherein the first network device and the second network device are base stations. [Item 9] generating first information, the first information indicating that a terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access; transmitting a first report to a first network device, the first report comprising the first information; A communication method comprising: [Item 10] 10. The method of claim 9, wherein the first report further comprises second information, the second information indicating two-stage random access quality thresholds. [Item 11] Item 9 or 10, wherein the first report further includes third information, and the third information includes at least one of the following information: information about a physical uplink shared channel (PUSCH) configured for the terminal device in two-stage random access, random access configuration information in two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH. [Item 12] 12. The method according to any one of claims 9 to 11, wherein the first report further comprises fourth information, and the fourth information indicates time information for the terminal device to fall back to four-stage random access. [Item 13] 13. The method according to any one of claims 9 to 12, wherein the first report further comprises fifth information, the fifth information indicating a cell from which the terminal device performs two-stage random access. [Item 14] The first report further comprises sixth information, the sixth information indicating at least one of the following information: a network type of the first cell, a frequency type of the first cell, a service type of the first cell, and a type of the first cell; 14. The method according to any one of claims 9 to 13, wherein the first cell is a cell in which the terminal device performs two-stage random access. [Item 15] A communication device comprising a communication unit and a processing unit, the communication unit and the processing unit being configured to support the communication device in executing the communication method according to any one of claims 1 to 8. [Item 16] A communication device comprising a communication unit and a processing unit, the communication unit and the processing unit being configured to support the communication device in executing a communication method according to any one of claims 9 to 14. [Item 17] A communications device comprising a processor, the processor coupled to a memory; the memory is configured to store a computer program; A communication device, wherein the processor is configured to execute the computer program stored in the memory, thereby enabling the device to perform the communication method described in any one of items 1 to 8. [Item 18] A communications device comprising a processor, the processor coupled to a memory; the memory is configured to store a computer program; A communication device, wherein the processor is configured to execute the computer program stored in the memory to enable the device to perform the communication method described in any one of items 9 to 14. [Item 19] A computer-readable storage medium comprising a program or instructions, which, when executed by a processor, performs the communication method according to any one of items 1 to 8. [Item 20] A computer-readable storage medium comprising a program or instructions, the program or instructions being executed by a processor to perform the communication method according to any one of items 9 to 14. [Item 21] A communication device according to item 15 and a communication device according to item 16, or A communication system comprising the communication device according to item 17 and the communication device according to item 18. [Item 22] Further comprising a second network device; 22. The communication system of claim 21, wherein the second network device is configured to receive some or all of the information in a first report and perform processing based on the some or all of the information in the first report, the first report having first information, the first information indicating that the terminal device passively falls back from two-stage random access to four-stage random access or actively falls back from two-stage random access to four-stage random access.

Claims

1. receiving a first report from a terminal device, where the first report includes first information used to determine a fallback scheme from two-stage random access to four-stage random access of the terminal device, the fallback scheme including active fallback or passive fallback; and A method of communication comprising performing an action based on the first report.

2. The method of claim 1 , wherein the step of performing an action based on the first report includes transmitting some or all of the information in the first report to another network device.

3. A step of receiving a first report from a terminal device, where the first report includes first information indicating whether the terminal device falls back from two-stage random access to four-stage random access; and performing an action based on the first report; A method of communications, wherein performing an action based on the first report includes transmitting some or all of the information in the first report to another network device.

4. If the first information indicates the active fallback, increasing a maximum number of transmissions of a random access preamble or msgA in the two-stage random access; or 2. The method of claim 1, further comprising adjusting allocation of time-frequency resources for transmitting data related to the two-stage random access if the first information indicates the passive fallback.

5. generating a first report, where the first report includes first information used to determine a fallback scheme from two-stage random access to four-stage random access of a terminal device, the fallback scheme including active fallback or passive fallback; and A method of communication comprising the step of transmitting the first report.

6. The communication method according to claim 1 , wherein the first report further includes second information, the second information indicating quality thresholds for the two stages of random access.

7. A method for receiving a first report from a terminal device, wherein the first report includes first information indicating whether the terminal device falls back from two-stage random access to four-stage random access; and performing an action based on the first report; The method of claim 1, wherein the first report further includes second information, the second information indicating quality thresholds for the two-stage random access.

8. 8. The communication method according to claim 1, wherein the first report further includes third information, and the third information includes at least one of the following information: information about a physical uplink shared channel (PUSCH) configured for the terminal device in the two-stage random access, random access configuration information in the two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

9. A method for receiving a first report from a terminal device, wherein the first report includes first information indicating whether the terminal device falls back from two-stage random access to four-stage random access; and performing an action based on the first report; The communication method, wherein the first report further includes third information, the third information including at least one of the following information: information about a physical uplink shared channel (PUSCH) configured for the terminal device in the two-stage random access, random access configuration information in the two-stage random access, and a correspondence relationship between the random access configuration information and the PUSCH.

10. 10. The communication method according to claim 1, wherein the first report further includes fourth information, and the fourth information indicates time information for the terminal device to fall back to the four-stage random access.

11. The communication method according to claim 1 , wherein the first report further includes fifth information, and the fifth information indicates cell information for the terminal device to perform the two-stage random access.

12. 12. The communication method according to claim 1, wherein the first report further includes sixth information, the sixth information indicating at least one of the following information: a network type of a first cell, a frequency type of the first cell, a service type of the first cell, and a type of the first cell, the first cell being a cell from which the terminal device performs the two-stage random access.

13. The communication method according to claim 1 , wherein the first report further includes information indicating a maximum number of transmissions of msgA in the two-stage random access.

14. A communication device, the communication device being configured to implement a communication method according to any one of claims 1 to 13.

15. A program for causing a processor to execute the communication method according to any one of claims 1 to 13.

16. A communication system comprising a first network device and a second network device, the first network device configured to implement the communication method of any one of claims 1, 3, 7 and 9, and the second network device configured to communicate with the first network device.

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