Random access method and apparatus

Abstract

Disclosed are a random access method and apparatus, relating to the technical field of communications. The method comprises: when a network device, after receiving a preamble sent by a terminal device, finds that a PUSCH occasion corresponding to the preamble is invalid, the network device actively sends feedback information to the terminal device indicating uplink authorization, so that the terminal device can send a PUSCH over a time-frequency resource indicated by the uplink authorization in a timely manner, and complete random access. Thus, the terminal device is prevented from sending on an invalid first PUSCH occasion corresponding to the preamble, thereby effectively shortening random access delay and improving the success rate of random access.

Description

Random access method and device

[0001] The present application claims priority from the Chinese patent application No. 202411396015.4 filed on September 30, 2024, and entitled "Random access method and device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

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

[0003] On a network energy saving (NES) cell, the transmission of synchronization signal and PBCH block (SSB) is allowed to be changed, for example, the transmission of SSB is turned on, the transmission of SSB is turned off, or the transmission pattern of SSB is changed. The idle state terminal device cannot perceive the change of SSB on the cell and does not know whether the validity of some physical uplink shared channel (PUSCH) occasions changes. If the terminal device performs random access, the random access message is sent on the invalid PUSCH occasion, which may cause the random access delay to increase, and even the random access to fail. SUMMARY

[0004] The present application provides a random access method and device, which can shorten the random access delay and improve the success rate of random access.

[0005] In a first aspect, a random access method is provided, which is executed by a terminal device or a module applied to the terminal device, and includes: receiving first system information indicating a first PUSCH occasion; sending a preamble in a first message; receiving a feedback message from a network device within a first time window; and sending a PUSCH in the first message according to an uplink grant indicated by the feedback message. The duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble.

[0006] The terminal device receives the first PUSCH occasion indicated by the first system information indication, and can initiate Type-2 random access (RA). The present application provides a method for a network device to indicate an uplink grant for Type-2 RA to a terminal device. Since the network device knows whether the first PUSCH occasion corresponding to the preamble is valid, the network device does not need to wait for the duration of the time window indicated by msgA-PUSCH-TimeDomainOffset-r16. After receiving the preamble, if the network device determines that the first PUSCH occasion corresponding to the preamble is invalid, the network device sends a feedback message to the terminal device to indicate the uplink grant. The terminal device receives the uplink grant indicated by the network device within the first time window, that is, the terminal device has learned the uplink grant before sending the PUSCH in the first message at the first PUSCH occasion corresponding to the preamble, and sends the PUSCH in the first message according to the uplink grant, thereby avoiding the terminal device to send at the invalid first PUSCH occasion corresponding to the preamble, shortening the random access delay and improving the success rate of random access.

[0007] The uplink grant indicates a specified time-frequency domain resource for transmitting the PUSCH, and the specified time-frequency domain resource is, for example, a valid PUSCH occasion. The valid PUSCH occasion is different from the first PUSCH occasion corresponding to the preamble.

[0008] The feedback message directly indicates the uplink grant, so that the terminal device can learn the uplink grant in time, send the PUSCH in the first message at the new valid PUSCH occasion indicated by the uplink grant, avoid sending at the invalid first PUSCH occasion corresponding to the preamble, shorten the random access delay, and improve the success rate of random access.

[0009] In a possible implementation, the feedback message further indicates the transmission state of the SSB. The terminal device can determine whether the corresponding PUSCH occasion is valid through the transmission state of the SSB, thereby avoiding sending the PUSCH at the invalid PUSCH, shortening the random access delay, and improving the success rate of random access.

[0010] In another possible implementation, the feedback message is a fallback random access response. For example, the feedback message is a special message B in Type-2 RA.

[0011] In another possible implementation, the method further includes receiving second system information from the network device, and the second system information indicates the first time window. For example, the second system information is a system information block type 1 (SIB1), and the SIB1 indicates the first time window.

[0012] By configuring the first time window, the terminal device monitors the feedback message of the network device after sending the preamble, in the case that the first PUSCH occasion corresponding to the preamble is invalid, the uplink authorization is learned in time, the PUSCH in the first message is sent according to the uplink authorization, the terminal device is prevented from sending on the invalid first PUSCH occasion corresponding to the preamble, the random access delay is shortened, and the random access success rate is improved.

[0013] In a second aspect, a random access method is provided, which is performed by a network device or a module applied to the network device, and includes: sending first system information, the first system information indicating a first PUSCH occasion; receiving a preamble in a first message from a terminal device; in the case that the first PUSCH occasion corresponding to the preamble is invalid, sending a feedback message before the first PUSCH occasion corresponding to the preamble in the first message, the feedback message indicating an uplink authorization; and receiving a PUSCH in the first message from the terminal device according to the uplink authorization.

[0014] In another possible implementation, the method further includes: sending second system information, the second system information indicating a first time window.

[0015] In a third aspect, a random access method is provided, which is performed by a terminal device or a module applied to the terminal device, and includes: at a first time, receiving a first message from a network device, the first message including a sending state of an SSB; and at a second time, updating a valid PUSCH occasion, the second time being later than the first time.

[0016] In this way, the network device dynamically adjusts the sending state of the SSB as needed, for example, after starting the sending of the SSB, stopping the sending of the SSB, or changing the sending pattern of the SSB, the concept of the second time is introduced, so that the terminal device knows when to re-determine the valid PUSCH occasion, and the ambiguity that may exist between the network device and the terminal device in the case of introducing the dynamic adjustment of the sending state of the SSB by the network device is eliminated.

[0017] In a possible implementation, the second time indicates a time unit in which the sending state of the SSB indicated by the first message is adjusted.

[0018] In another possible implementation, the second time indicates a time unit in which the first message is located.

[0019] In another possible implementation, the second time indicates a next time unit of the time unit in which the first message is located.

[0020] The time unit is in units of a slot, a subframe, or a symbol.

[0021] In a possible implementation, the transmission state of the SSB comprises starting transmission of the SSB, stopping transmission of the SSB, or changing a transmission pattern of the SSB.

[0022] In a possible implementation, the first message is a media access control-control element (MAC-CE), a downlink control information (DCI), or a radio resource control (RRC) reconfiguration message.

[0023] In a fourth aspect, a communication apparatus is provided. Benefits can be derived from the description of the first aspect, the second aspect, or the third aspect. The communication apparatus has functions of the method of the first aspect, the second aspect, or the third aspect. The functions can be implemented by hardware, or by executing corresponding software with hardware. The hardware or software includes one or more modules corresponding to the functions. In a possible design, the communication apparatus includes a transceiver and a processing unit.

[0024] When the communication apparatus is configured to implement the functions of the terminal device, the transceiver is configured to receive first system information indicating a first PUSCH occasion; the transceiver is further configured to transmit a preamble in a first message, and receive, within a first time window, a feedback message from the network device, the feedback message indicating an uplink grant; and the transceiver is further configured to transmit, according to the uplink grant, a PUSCH in the first message. A duration of the first time window is less than an interval between the preamble and the first PUSCH occasion corresponding to the preamble. The processing unit is configured to determine the uplink grant according to the feedback message.

[0025] When the communication apparatus is configured to implement the functions of the network device, the transceiver is configured to transmit first system information indicating a first PUSCH occasion; the transceiver is further configured to receive a preamble from the terminal device; and in a case where the first PUSCH occasion corresponding to the preamble is invalid before the first PUSCH occasion corresponding to the preamble, the transceiver is further configured to transmit a feedback message indicating an uplink grant; and the transceiver is further configured to receive, according to the uplink grant, a PUSCH in a first message from the terminal device. The processing unit is configured to determine that the first PUSCH occasion corresponding to the preamble is invalid.

[0026] The modules can perform the corresponding functions in the method examples of the first aspect, the second aspect, or the third aspect. For details, refer to the descriptions of the method examples.

[0027] In a fifth aspect, a communication apparatus is provided. The communication apparatus can be a terminal device in the method embodiments, or a chip arranged in the terminal device. The communication apparatus includes a communication interface and a processor, and optionally, a memory. The memory is configured to store computer programs or instructions. The processor is coupled to the memory and the communication interface. When the processor executes the computer programs or instructions, the communication apparatus performs the method performed by the terminal device in the method embodiments.

[0028] In a sixth aspect, a communication apparatus is provided. The communication apparatus can be a network device in the method embodiments, or a chip arranged in the network device. The communication apparatus includes a communication interface and a processor, and optionally, a memory. The memory is configured to store computer programs or instructions. The processor is coupled to the memory and the communication interface. When the processor executes the computer programs or instructions, the communication apparatus performs the method performed by the network device in the method embodiments.

[0029] In a seventh aspect, a computer program product is provided. The computer program product includes computer program codes. When the computer program codes are executed, the method performed by the terminal device in the aspects is performed.

[0030] In an eighth aspect, a computer program product is provided. The computer program product includes computer program codes. When the computer program codes are executed, the method performed by the network device in the aspects is performed.

[0031] In a ninth aspect, a chip system is provided. The chip system includes a processor configured to implement the functions of the terminal device in the methods in the aspects. In a possible design, the chip system further includes a memory configured to store program instructions and / or data. The chip system can be composed of a chip, or include a chip and other discrete devices.

[0032] In a tenth aspect, a chip system is provided. The chip system includes a processor configured to implement the functions of the network device in the methods in the aspects. In a possible design, the chip system further includes a memory configured to store program instructions and / or data. The chip system can be composed of a chip, or include a chip and other discrete devices.

[0033] In an eleventh aspect, a computer readable storage medium is provided. The computer readable storage medium stores a computer program. When the computer program is executed, the method performed by the terminal device in the aspects is implemented.

[0034] In a twelfth aspect, a computer-readable storage medium is provided, and the computer-readable storage medium stores a computer program. When the computer program is executed, the method performed by the network device in the above aspects is implemented.

[0035] The technical effects brought by the implementation manners of any one of the second aspect to the twelfth aspect can refer to the technical effects brought by the corresponding implementation manners of the first aspect and the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a schematic diagram of an architecture of a communication system provided by the present application;

[0037] FIG. 2 is a schematic diagram of a random access process provided by the present application;

[0038] FIG. 3 is a schematic diagram of a time domain relative position between a PRACH slot and a PUSCH slot in a MsgA provided by the present application;

[0039] FIG. 4 is a schematic diagram of a time-frequency resource structure provided by the present application;

[0040] FIG. 5 is a schematic diagram of an SSB time-frequency domain structure, SSB beam sweeping, and SSB burst set transmission period provided by the present application;

[0041] FIG. 6 is a schematic diagram of a terminal device in an idle state on an NES cell performing Type-2 RA on an invalid PUSCH occasion provided by the present application;

[0042] FIG. 7 is a schematic diagram of a random access method provided by the present application;

[0043] FIG. 8 is a schematic diagram of a configuration of a first time window provided by the present application;

[0044] FIG. 9 is a schematic diagram of another random access method provided by the present application;

[0045] FIG. 10 is a schematic diagram of updating a valid PUSCH occasion provided by the present application;

[0046] FIG. 11 is a schematic diagram of a structure of a communication apparatus provided by the present application;

[0047] FIG. 12 is a schematic diagram of a structure of another communication apparatus provided by the present application. DETAILED DESCRIPTION

[0048] FIG. 1 is a schematic diagram of an architecture of a communication system provided by an embodiment of the present application. As shown in FIG. 1, the communication system 1000 includes a radio access network (RAN) 100, wherein the RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG. 1, collectively referred to as 110), and can further include at least one terminal (e.g., 120a-120j in FIG. 1, collectively referred to as 120). The RAN 100 can further include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG. 1). The terminals 120 are connected to the RAN nodes 110 in a wireless manner. Terminals and terminals, and RAN nodes and RAN nodes can be connected to each other in a wired or wireless manner. The communication system 1000 can further include a core network 200. The RAN nodes 110 are connected to the core network 200 in a wireless or wired manner. The core network devices in the core network 200 and the RAN nodes 110 in the RAN 100 can be independent and different physical devices, or can be the same physical device integrated with the logical functions of the core network devices and the logical functions of the RAN nodes. The communication system 1000 can further include the Internet 300.

[0049] The RAN 100 can be an evolved universal terrestrial radio access system, a new radio (NR) system, and a future wireless access system defined in the 3rd generation partnership project (3GPP). The RAN 100 can further include two or more different wireless access systems described above. The RAN 100 can also be an open RAN (O-RAN).

[0050] The RAN node, also referred to as a radio access network device, a RAN entity, or an access node, is used to help terminals access the communication system in a wireless manner. In an application scenario, the RAN node can be a base station, an evolved base station, a transmission and reception point, a next-generation base station in a 5th generation mobile communication system, or a base station in a future mobile communication system. The RAN node can be a macro base station (e.g., 110a in FIG. 1), a micro base station or an indoor station (e.g., 110b in FIG. 1), or a relay node or a donor node. The network device refers to the radio access network device.

[0051] In another application scenario, a terminal can access a wireless network through cooperation of multiple RAN nodes, and different RAN nodes implement part of functions of a base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). The CU here implements functions of a radio resource control protocol and a packet data convergence layer protocol of the base station, and can also implement a function of a service data adaptation protocol; the DU implements functions of a radio link control layer and a medium access control layer of the base station, and can also implement part of a physical layer or all of the physical layer; for specific descriptions of the above protocol layers, refer to relevant technical specifications of the 3GPP. The RU can be used to implement a function of transceiving a radio frequency signal. The CU and the DU can be two independent RAN nodes, or can be integrated in the same RAN node, for example, integrated in a baseband unit. The RU can be included in a radio frequency device, for example, included in a radio frequency remote unit or an active antenna unit. The CU can be further divided into two types of RAN nodes: a CU-control plane and a CU-user plane.

[0052] In different systems, a RAN node can have different names. For example, in an O-RAN system, a CU can be referred to as an open CU (O-CU), a DU can be referred to as an open DU (O-DU), and an RU can be referred to as an open RU (O-RU). The RAN node in the embodiments of the present application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. For example, the RAN node can be a server loaded with a corresponding software module. The embodiments of the present application do not limit specific technologies and specific device forms adopted by the RAN node. For ease of description, a base station is described as an example of the RAN node in the following.

[0053] A terminal is a device with wireless transceiver function, which can send signals to a base station or receive signals from a base station. A terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. A terminal can be widely applied in various scenarios, such as device-to-device (D2D), vehicle to everything (V2X) communication, machine type communication, Internet of Things, virtual reality, augmented reality, industrial control, autonomous driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. A terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, airplane, ship, robot, mechanical arm, smart home device, etc. Embodiments of the present application do not limit the specific technology and specific device form of the terminal.

[0054] A base station and a terminal can be in a fixed position or movable. A base station and a terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water surface; can also be deployed on an airplane, balloon and artificial satellite. Embodiments of the present application do not limit the application scenarios of a base station and a terminal.

[0055] The roles of a base station and a terminal can be relative, for example, the helicopter or drone 120i in FIG. 1 can be configured as a mobile base station, and for those terminals 120j accessing the wireless access network 100 through 120i, the terminal 120i is a base station; but for the base station 110a, 120i is a terminal, that is, 110a and 120i communicate through a wireless air interface protocol. Of course, 110a and 120i can also communicate through a base station-to-base station interface protocol, at this time, relative to 110a, 120i is also a base station. Therefore, a base station and a terminal can be collectively referred to as a communication apparatus, 110a and 110b in FIG. 1 can be referred to as a communication apparatus with base station function, and 120a-120j in FIG. 1 can be referred to as a communication apparatus with terminal function.

[0056] A base station and a terminal, a base station and a base station, a terminal and a terminal can communicate through licensed spectrum, can also communicate through unlicensed spectrum, and can also communicate through licensed spectrum and unlicensed spectrum at the same time; can communicate through spectrum below 6 gigahertz (GHz), can also communicate through spectrum above 6 GHz, and can also communicate through spectrum below 6 GHz and spectrum above 6 GHz at the same time. Embodiments of the present application do not limit the spectrum resources used for wireless communication.

[0057] In the embodiments of the present application, the functions of the base station can also be performed by a module (such as a chip) in the base station, or by a control subsystem containing the functions of the base station. The control subsystem containing the functions of the base station herein can be a control center in the above-mentioned application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal can also be performed by a module (such as a chip or a modem) in the terminal, or by a device containing the functions of the terminal.

[0058] In the present application, the base station sends a downlink signal or downlink information to the terminal, and the downlink information is carried on a downlink channel; the terminal sends an uplink signal or uplink information to the base station, and the uplink information is carried on an uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection on a cell controlled by the base station. The cell with which the terminal establishes a wireless connection is called the service cell of the terminal. When the terminal communicates with the service cell, it will also be interfered by signals from neighboring cells.

[0059] In the embodiments of the present application, the time domain symbol can be an orthogonal frequency division multiplexing symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol. If not specified, the symbol in the embodiments of the present application refers to a time domain symbol.

[0060] It can be understood that, in the embodiments of the present application, the physical downlink control channel (PDCCH) and the PUSCH are only used as an example of a downlink control channel and an uplink data channel, respectively. In different systems and different scenarios, data channels and control channels can have different names, and the embodiments of the present application do not limit this.

[0061] In order to facilitate understanding, the main terms involved in the present application are explained.

[0062] The random access procedure refers to the process from the start of sending a preamble for random access by the terminal device to attempt to access the network device to the establishment of a basic signaling connection between the network device.

[0063] Random access is a basic and important process in a long term evolution system. The main purposes of random access include establishing uplink synchronization, dynamically allocating a unique identifier of a terminal device by a network device, such as a cell radio network temporary identifier of the terminal device, and requesting the network device to allocate an uplink resource to the terminal device. Random access is not only used for initial access, but also used for new cell access in a handover process, access after a radio link failure, and recovery of uplink synchronization during uplink data transmission or downlink data transmission.

[0064] Random access is divided into contention-based random access (CBRA) and contention-free random access (CFRA). The random access mentioned below refers to contention-based random access.

[0065] In NR, random access includes Type-1 RA and Type-2 RA. Type-1 RA is also called 4-step RA. Type-2 RA is also called 2-step RA. Compared with Type-1 RA, Type-2 RA contains a two-step interaction process between the network device and the terminal device, which greatly reduces the time delay in the random access process.

[0066] For a UE in an RRC_CONNECTED state (referred to as a connected state, that is, the UE has established an RRC connection with the network device) and a UE in an RRC_IDLE / RRC_INACTIVE state (referred to as an idle state, that is, the UE has not established an RRC connection with the network), it is possible to initiate a Type-2 RA process to the network device. For example, for an idle state UE, the UE performs uplink synchronization and completes initial access through Type-2 RA. For a connected state UE, when uplink synchronization is problematic, the UE performs uplink synchronization again through Type-2 RA.

[0067] FIG. 2 is a process diagram of random access provided by the present application. As shown in (a) of FIG. 2, it is a process of Type-1 RA provided by the present application.

[0068] Step 1, the terminal device sends a random access request to the network device. The random access request includes a preamble. Correspondingly, the network device receives the random access request from the terminal device. Step 2, the network device sends a random access response to the terminal device. Correspondingly, the terminal device receives the random access response from the network device.

[0069] A terminal device randomly selects a preamble from a preamble pool and initiates a contention-based random access on a physical random access channel (PRACH). For example, there can be multiple terminal devices selecting the same preamble at the same time to initiate random access.

[0070] The terminal device continuously monitors the PDCCH in the random access response window to receive a random access response.

[0071] In the case that no random access response from the network device is received in the random access response window, the random access procedure fails.

[0072] In the case that a random access response from the network device is received in the random access response window, and the preamble in the random access response is the same as the preamble sent by the terminal device, the random access procedure succeeds. The random access response also indicates the uplink grant PUSCH occasion.

[0073] Step 3, the terminal device sends a connection request to the network device. Correspondingly, the network device receives the connection request from the terminal device. Step 4, the network device sends a connection completion to the terminal device. Correspondingly, the terminal device receives the connection completion from the network device.

[0074] After the terminal device obtains the uplink grant PUSCH occasion, it sends uplink data based on the uplink grant PUSCH occasion. The terminal device starts a contention resolution timer to continuously monitor the PDCCH. After receiving an acknowledgement from the network device, the terminal device determines that the connection is successful.

[0075] As shown in (b) of FIG. 2, a Type-2 RA procedure provided by the present application is shown. In step 1, the terminal device sends a message A (MsgA) to the network device. Correspondingly, the network device receives the MsgA from the terminal device.

[0076] The MsgA contains a preamble and a PUSCH corresponding to the preamble. The network device needs to provide configuration information of the preamble and configuration information of the PUSCH corresponding to the preamble, i.e. configuration information of the preamble resource and the PUSCH resource, including but not limited to time-frequency locations of the two resources.

[0077] The preamble included in MsgA in Type-2 RA corresponds to the preamble included in the random access request in Type-1 RA; the PUSCH included in MsgA in Type-2 RA corresponds to the PUSCH in the connection request in Type-1 RA. In Type-1 RA, after the terminal device sends the random access request to the network device, the terminal device needs to wait for the random access response fed back by the network device before continuing to send the connection request to the network device. In Type-2 RA, the terminal device can transmit MsgA including the preamble and the PUSCH corresponding to the preamble at one time, without waiting for the network device to feed back the random access response in between, thus shortening the random access delay.

[0078] In Type-2 RA, the PUSCH is sent later than the preamble. The interval between the preamble and the preamble corresponding PUSCH occasion is given by the information element msgA-PUSCH-TimeDomainOffset-r16. For example, as shown in FIG. 3, a schematic diagram of the relative time domain position between the PRACH slot and the PUSCH slot in MsgA is provided. The interval between the preamble and the preamble corresponding PUSCH occasion is in units of slots, indicating the relative position between the first symbol of the slot (i.e., the PRACH slot) where the preamble resource is located and the first symbol of the slot (i.e., the PUSCH slot) where the PUSCH resource is located. After the terminal device receives the above configuration information, the terminal device determines the interval between the preamble and the preamble corresponding PUSCH when sending MsgA.

[0079] For the terminal device in the idle state, the information element msgA-PUSCH-TimeDomainOffset-r16 is obtained from the SIB1 broadcast by the network device.

[0080] For the terminal device in the connected state, the information element msgA-PUSCH-TimeDomainOffset-r16 is obtained from the RRC reconfiguration message sent by the network device.

[0081] Since the terminal device performs contention-based random access, the above configuration information of the preamble resource and the PUSCH resource is public and can be obtained by any terminal device. If multiple terminal devices obtain the configuration information and initiate random access at the same time, a contention conflict may occur, resulting in random access failure.

[0082] Step 2, the network device sends a message B (MsgB) to the terminal device. Correspondingly, the terminal device receives MsgB from the network device. MsgB is used for contention resolution.

[0083] After the terminal device sends MsgA, it monitors the MsgB feedback from the network device. The network device needs to monitor a DCI format 1_0 scrambled with MsgB-RNTI (used to further indicate to the terminal device how to receive the MsgB message) within a time window. The length of this time window is given by the information element msgB-ResponseWindow-r16.

[0084] For the terminal device in idle state, the information element msgB-ResponseWindow-r16 is obtained from the SIB1 broadcasted by the network device.

[0085] For the terminal device in connected state, the information element msgB-ResponseWindow-r16 is obtained from the RRC reconfiguration message sent by the network device.

[0086] In some embodiments, the network device successfully receives the preamble in MsgA, but fails to receive the PUSCH due to some reasons. For example, multiple terminal devices send messages on the same block of PUSCH resources, causing contention, reception failure. In this case, the network device sends a special MsgB, carrying a fallback random access response (FallbackRAR), in the time window indicated by msgB-ResponseWindow-r16. The fallback random access response indicates the failure of PUSCH transmission in MsgA. At this time, the terminal device falls back from Type-2 RA to Type-1 RA, i.e. the MsgB carrying the FallbackRAR contains an uplink grant, which allocates a dedicated PUSCH resource to the terminal device, so there is no need for contention, and the terminal device retransmits on the uplink grant PUSCH resource. The MsgB carrying the FallbackRAR is equivalent to the random access response in step 2 of Type-1 RA, and the retransmitted PUSCH is equivalent to the connection request in step 3 of Type-1 RA. Obviously, the above process ensures that in abnormal situations (e.g. multiple terminal devices competing for the same block of common PUSCH resources for Type-2 RA, causing network device reception failure), the terminal device can still fall back from Type-2 RA to Type-1 RA with higher latency but more stable Type-1 RA to continue to initiate random access.

[0087] The NR specification also defines valid PUSCH resources, i.e. after the network device indicates the location of the PUSCH time-frequency resource to the terminal device, the terminal device also needs to further determine whether the configured PUSCH resource is valid according to some rules, and perform Type-2 RA based on the valid PUSCH resource.

[0088] In the following, the terms PUSCH resource and PUSCH occasion can be used interchangeably.

[0089] According to the NR specification, a PUSCH occasion is a valid PUSCH occasion if the following conditions are met.

[0090] 1. The PUSCH occasion does not overlap with a valid PRACH occasion in time and frequency domain, and the valid PRACH occasion is used for Type-1 RA or Type-2 RA.

[0091] 2. The PUSCH occasion and SSBs need to meet the following conditions in time domain location. The time domain location of SSBs is provided by ssb-PositionsInBurst information element in SIB1 or ServingCellConfigCommon in RRC.

[0092] ① If the terminal device is not configured tdd-UL-DL-ConfigurationCommon, the PUSCH occasion cannot be located in front of an SSB in a PUSCH slot, and needs to be located at least N symbols after the last SSB.

[0093] ② If the terminal device is configured tdd-UL-DL-ConfigurationCommon, the PUSCH occasion needs to be located in an UL symbol, or: cannot be located in front of an SSB in a PUSCH slot, and needs to be located at least N symbols after the last SSB.

[0094] Through the definition of valid PUSCH occasions, the terminal device can further determine the valid PUSCH resources that can be used for transmitting Type-2 RA MsgA according to the occupation of PRACH, SSB, etc. in time and frequency domain resources.

[0095] In the time domain, the time-frequency resource structure of 5G NR includes frame, subframe, slot, and symbol. For example, as shown in FIG. 4, the frame length is fixed at 10 milliseconds, and the frame number ranges from 0 to 1023. The subframe length is fixed at 1 ms, and the subframe number ranges from 0 to 9. In the case of using a normal cyclic prefix, the slot length is 14 symbols. The symbol length is not fixed and is related to the subcarrier spacing.

[0096] The scheduling time unit in the data domain of 5G NR is a slot. Although the length of the slot is determined by the number of symbols, the length of the symbol is related to the subcarrier spacing, so the length of the slot is not fixed. For example, when the subcarrier spacing is 15 kHz, there is 1 slot in each subframe (1 ms); and when the subcarrier spacing is 120 kHz, there are 8 slots in each subframe (1 ms).

[0097] The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The terminal device continuously performs cell search and measurement based on the SSB when moving in the system, selects a suitable SSB beam, and realizes initial access and mobility management of the terminal device. As shown in (a) of FIG. 5, each SS / PBCH Block occupies 4 consecutive symbols in the time domain and 20 resource blocks (i.e., 240 subcarriers) in the frequency domain. Among them, the PSS and the SSS occupy 127 subcarriers in the first symbol and the third symbol of the SSB, respectively. The PBCH (which includes a demodulation reference signal) occupies the second symbol and the fourth symbol of the entire SSB, and additionally occupies 48 subcarriers at both ends of the third symbol.

[0098] In NR, the SSB is transmitted in the form of beam sweeping, that is, the network device transmits a beam direction at a certain time, and covers the entire cell in the required direction by transmitting different beams at multiple times, as shown in (b) of FIG. 5. A certain round of beam sweeping transmits N SS / PBCH Blocks in different directions, and the entire transmission of this round is called an SSB burst set (SSB Burst). In order to avoid ambiguity, in the following, SS / PBCH Block refers to a single SSB signal occupying 4 symbols in the time domain, and SSB Burst refers to the entire SS / PBCH Block transmitted in a round of beam sweeping.

[0099] NR specifies that, when the terminal device initially accesses, the period of the SSB burst set is 20 ms, and the transmission window of the SSB burst set is performed in units of half frames (5 ms in length). As shown in (c) of FIG. 5, within the 20 ms period, the SSB burst set is always limited to a time interval of 5 ms (half frame in length), and the remaining 15 ms does not transmit SSB.

[0100] In some embodiments, the network device periodically transmits SSB, regardless of the needs of the network device or the terminal device, and the SSB burst set is continuously transmitted according to the configured period.

[0101] Network energy saving refers to that NR supports multiple techniques for changing the signal transmission mode in the time domain, so as to reduce the overhead and power consumption of the network device, and achieve the effect of network energy saving. In the following, the cell that can support configuring such a technique will be referred to as a network energy saving cell (NES cell). The following introduces two key NES techniques related to the SSB signal.

[0102] On-demand SSB refers to that the network device starts to send SSB and instructs the terminal device to receive SSB when there is a specific demand. The on-demand SSB sending mode on a cell has been supported. When there is no demand, the network device does not send SSB, and when there is demand, the network device sends SSB and sends signaling to instruct the terminal device to receive the SSB. The demand includes the need to use SSB for cell measurement, time-frequency synchronization, cell activation, and the like. In this way, the network device dynamically decides whether to send SSB signals on the cell according to whether there is a demand, and achieves the energy saving effect compared with the strategy of always sending SSB signals.

[0103] SSB time domain characteristic dynamic change refers to that the network device sends signaling to the terminal device to inform the terminal device of the information of the changed time domain characteristic of SSB, and sends a kind of SSB with different time domain characteristics. The terminal device receives SSB according to the new configuration. The time domain characteristic of SSB on a cell has been changed. Specifically, the time domain characteristics that SSB can change include the following two kinds.

[0104] 1. In units of SSB burst set, including changing the period of SSB. For example, a kind of SSB with a period of 20 ms is sent on a cell, and at a certain moment, the network device instructs the terminal device to send a kind of SSB with a period of 160 ms.

[0105] 2. In units of SS / PBCH Block, including changing the position and number of SS / PBCH Block inside an SSB burst set. For example, a kind of SSB with a specific pattern is sent on a cell, and at a certain moment, the network device instructs the terminal device to send a kind of SSB with a new pattern, and the position or number of SS / PBCH Block inside each SSB burst set changes compared with before.

[0106] In this way, the network device can dynamically adjust the period, beam number and position of SSB according to the actual demand (for example, in the middle of the night, the user is less, and a kind of SSB sending mode with longer period and fewer beams can be changed), and compared with the strategy of always sending SSB signals with fixed period and fixed beam number and position, the energy saving effect is achieved.

[0107] On the NES cell, it is allowed to change the sending state of SSB, for example, to start sending SSB, to stop sending SSB, or to change the sending pattern of SSB. The idle state terminal device cannot perceive the change of SSB on the cell and does not know whether the validity of certain PUSCH occasions changes. If the terminal device performs random access and sends a random access message on an invalid PUSCH occasion, it may cause the random access delay to increase, and even the random access to fail.

[0108] The invalid PUSCH occasion is illustrated by taking a scenario of two terminal devices as an example, and the scenario of multiple terminal devices is not described further. As shown in (a) of FIG. 6, it is assumed that UE 1 has established an RRC connection with a network device, and UE 1 supports transmission of on-demand SSBs or dynamic change of SSB time-domain characteristics on a cell. UE 2 has not established an RRC connection with the network, and the idle-state UE 2 obtains the configuration of Type-2 RA on the cell through SIB1 broadcast on the cell, including the interval between the preamble and the PUSCH occasion corresponding to the preamble indicated by the information element msgA-PUSCH-TimeDomainOffset-r16. At a certain moment, the network device indicates to UE 1 that the on-demand SSB starts to be transmitted or the SSB time-domain characteristics are changed, at this time, the idle-state UE 2 cannot obtain this information through such connection-state signaling (such as an RRC message or a MAC-CE or a DCI). At a certain time later, UE 2 initiates Type-2 RA to the network device, and UE 2 transmits MsgA on a certain PUSCH occasion according to the configuration in SIB1, but this PUSCH occasion may have changed in validity because of the triggered / changed SSB, in other words, UE 2 may transmit MsgA on an invalid PUSCH occasion.

[0109] As shown in (b) of FIG. 6, the network device cannot successfully receive MsgA transmitted by UE 2 on the invalid PUSCH occasion, and the network device sends a MsgB carrying a FallbackRAR to UE 2, indicating the above-mentioned grant, so that UE 2 performs random access again on a new specified PUSCH resource.

[0110] To solve the problem of increasing random access latency or random access failure, the present application provides a random access method, which comprises that a network device configures a terminal device with a new first time window, the duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble. The terminal device initiates a Type-2 RA procedure, and monitors a feedback message within the first time window after transmitting the preamble in the first message. After receiving the preamble, the network device determines that the first PUSCH occasion corresponding to the preamble is invalid, and sends a feedback message to the terminal device within the first time window, the feedback message indicating an uplink grant. After receiving the feedback message within the first time window, the terminal device transmits the PUSCH in the first message according to the uplink grant indicated by the feedback message, and the network device receives the PUSCH in the first message from the terminal device according to the uplink grant.

[0111] After the terminal device sends the preamble in MsgA to the network device, it waits for the time window indicated by msgA-PUSCH-TimeDomainOffset-r16 before continuing to send the PUSCH in the MsgA message. If the terminal device subsequently continues to send on an invalid PUSCH occasion, the terminal device has to wait for a considerable period of time from beginning to end to obtain a new designated PUSCH occasion indicated by MsgB for re-random access, for example, the terminal device monitors the network device for feedback of a new designated PUSCH occasion within the time window indicated by msgB-ResponseWindow-r16, resulting in an increase in random access latency or random access failure.

[0112] The present application provides a method for a network device to indicate an uplink grant for Type-2 RA to a terminal device. Since the network device knows whether the first PUSCH occasion corresponding to the preamble is valid, the network device does not need to wait for the duration of the time window indicated by msgA-PUSCH-TimeDomainOffset-r16. After receiving the preamble, if the network device determines that the first PUSCH occasion corresponding to the preamble is invalid, it sends a feedback message to the terminal device indicating the uplink grant. The terminal device receives the indication of the uplink grant from the network device within the first time window, i.e., the terminal device has already learned the uplink grant before sending the PUSCH in the first message at the first PUSCH occasion corresponding to the preamble, and sends the PUSCH in the first message according to the uplink grant, thereby avoiding the terminal device to send at the invalid first PUSCH occasion corresponding to the preamble, shortening the random access latency, and improving the success rate of random access.

[0113] On an NES cell, the network device knows the transmission state of the SSB and how the transmission state of the SSB affects the validity of each PUSCH occasion in the time domain, but the idle-state terminal device does not. Therefore, after the terminal device sends the preamble and the network device successfully receives the preamble, the network device knows whether the PUSCH to be sent by the terminal device is on a valid PUSCH occasion, does not need to wait for the duration of the time window indicated by msgA-PUSCH-TimeDomainOffset-r16, and indicates an uplink grant to the terminal device to re-perform random access, thereby shortening the random access latency, improving the success rate of random access, and ensuring the normal progress of Type-2 RA on the NES cell.

[0114] The embodiments of the random access method provided by the present application are described in detail below with reference to the accompanying drawings.

[0115] Next, the method of random access is described in detail. Here, the terminal device randomly accesses the network device is taken as an example for description. The terminal device does not establish RRC connection with the network device, and the terminal device is in idle state. The terminal device and the network device are, for example, the terminal and the base station shown in FIG. 1. As shown in FIG. 7, the method includes the following steps.

[0116] Step 710, the network device sends the first system message, and the first system message indicates the first PUSCH occasion. Correspondingly, the terminal device receives the first system message from the network device.

[0117] The network device indicates the available PUSCH occasion to the terminal device through the first system information. The first system information is, for example, SIB1. Since the terminal device knows the available PUSCH occasion in advance, when the terminal device initiates the contention-based random access, the terminal device sends the MsgA by adopting the Type-2 RA procedure.

[0118] Step 720, the terminal device sends the preamble, and the preamble is the preamble in the first message. Correspondingly, the network device receives the preamble from the terminal device.

[0119] The terminal device initiates the contention-based random access by sending the PRACH, for example, the terminal device initiates the Type-2 RA procedure by sending the PRACH. The first message is, for example, the MsgA in the Type-2 RA. The preamble contained in the first message can be the preamble randomly selected by the terminal device from the preamble pool.

[0120] After the terminal device sends the preamble contained in the first message, the terminal device monitors the feedback message from the network device. For example, starting from the time slot in which the first symbol after the preamble is located, the terminal device monitors the feedback message from the network device.

[0121] The monitoring duration of the feedback message from the network device is the first time window. That is, the terminal device monitors the feedback message from the network device within the first time window.

[0122] The duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble. That is, the duration of the first time window is less than the duration of the time window indicated by the element msgA-PUSCH-TimeDomainOffset-r16.

[0123] Optionally, the first time window is in units of time slots, symbols or subframes. The duration of the first time window is configured as any value in 1-32 time slots. For example, the duration of the first time window contains more than 3 time slots in 1-32 time slots.

[0124] Understandably, the terminal device can receive the feedback message sent by the network device before sending the PUSCH in the first message.

[0125] At step 730, the network device sends the feedback message before the first PUSCH occasion corresponding to the preamble in the first message, in the case that the first PUSCH occasion corresponding to the preamble is invalid. Correspondingly, the terminal device receives the feedback message from the network device.

[0126] Since the network device knows the valid PUSCH occasions specified by NR and the first PUSCH occasion corresponding to the preamble, after receiving the preamble from the terminal device, the network device can know whether the first PUSCH occasion corresponding to the preamble is valid.

[0127] For example, the valid PUSCH occasions are related to SSB. In the case that the network device changes the sending state of SSB, the validity of the PUSCH occasion determined according to SSB can also change. After receiving the preamble from the terminal device, the network device determines the validity of the first PUSCH occasion corresponding to the preamble according to the sending state of SSB on the current cell. The sending state of SSB includes starting sending SSB, stopping sending SSB, or changing the sending pattern of SSB.

[0128] In the case that the first PUSCH occasion corresponding to the preamble is invalid, the network device sends the feedback message to the terminal device before the first PUSCH occasion corresponding to the preamble. The feedback message indicates the uplink grant. The present application does not limit the way in which the network device determines the valid PUSCH occasion, for example, the determination way of the valid PUSCH occasion specified by NR described above.

[0129] In some embodiments, the network device sends the feedback message within a first time window. The duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble.

[0130] It can be understood that, before the network device receives the PUSCH contained in the first message from the terminal device, the network device has already learned that the first PUSCH occasion corresponding to the preamble is invalid, and does not need to wait for a duration of a time window indicated by msgA-PUSCH-TimeDomainOffset-r16 to determine that the first PUSCH occasion corresponding to the preamble is invalid, and the valid PUSCH occasion is informed to the terminal device in advance. Therefore, the terminal device has learned the uplink grant before the PUSCH in the first message is sent at the first PUSCH occasion corresponding to the preamble, and the terminal device sends the PUSCH in the first message according to the uplink grant, thereby shortening the random access delay in the case that the first PUSCH occasion corresponding to the preamble is invalid, avoiding the terminal device from sending at the invalid PUSCH occasion, and improving the random access success rate.

[0131] The feedback message is, for example, MsgB in Type-2 RA. For example, the feedback message is, for example, a fallback random access response. The difference from MsgB in Type-2 RA is that, in the case that the first PUSCH occasion corresponding to the preamble is invalid, the network device indicates the uplink grant to the terminal device in the first time window in advance relative to the time window indicated by msgA-PUSCH-TimeDomainOffset-r16.

[0132] In some embodiments, the uplink grant indicates a specified time-frequency domain resource for transmitting the PUSCH, and the specified time-frequency domain resource is, for example, a valid PUSCH occasion. The valid PUSCH occasion is different from the first PUSCH occasion corresponding to the preamble.

[0133] In another embodiment, in the case that the network device changes the transmission state of the SSB, the feedback message includes the transmission state of the SSB. The transmission state of the SSB is used by the terminal device to determine the valid PUSCH occasion. Therefore, the network device does not need to indicate the uplink grant in the feedback message, but the terminal device directly selects the valid PUSCH occasion to send the PUSCH in the first message according to the transmission state of the SSB.

[0134] For example, the feedback message includes a first information field. The first information field is used to indicate the start of the transmission of the SSB and the stop of the transmission of the SSB. For example, the first information field includes 1 bit. In the case that the value of the first information field is 0, the transmission of the SSB is stopped, and in the case that the value of the first information field is 1, the transmission of the SSB is started. Alternatively, in the case that the value of the first information field is 1, the transmission of the SSB is stopped, and in the case that the value of the first information field is 0, the transmission of the SSB is started.

[0135] Optionally, the feedback message comprises a second information field, the second information field comprises a plurality of bits, and the plurality of bits are used to indicate a transmission pattern of the SSB. The transmission pattern of the SSB can indicate a beam distribution of the SSB burst or a period of the SSB burst. The transmission pattern of the SSB can be directly indicated by the second information field. Alternatively, a plurality of candidate transmission patterns of the SSB can be predefined by a protocol or indicated by the network device to the terminal device through the first system message, and the second information field indicates one of the plurality of candidate transmission patterns of the SSB.

[0136] The configuration information of the feedback message, for example, follows the configuration of MsgB in the existing protocol, or can be provided by adding a new configuration message in SIB1.

[0137] When the terminal device initiates the contention-based random access, the terminal device sends the MsgA by using the Type-2 RA procedure. In the case that the preamble corresponding PUSCH occasion is invalid, the terminal device has obtained the uplink grant before sending the PUSCH in the first message at the first PUSCH occasion corresponding to the preamble. The terminal device sends the PUSCH in the first message according to the uplink grant, and does not need to wait for the indication of the PUSCH occasion by the network device after sending the preamble in the Type-1 RA procedure. Therefore, the random access delay in the case that the preamble corresponding PUSCH occasion is invalid is shortened.

[0138] In step 740, the terminal device sends the PUSCH in the first message according to the uplink grant. Correspondingly, the network device receives the PUSCH in the first message from the terminal device.

[0139] After the terminal device sends the preamble contained in the first message, the terminal device monitors the feedback message from the network device. The terminal device receives the feedback message from the network device within a first time window, and the feedback message indicates the uplink grant.

[0140] In some embodiments, since the duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble, the terminal device has obtained the uplink grant indicated by the feedback message before sending the PUSCH in the first message at the invalid first PUSCH occasion corresponding to the preamble. The terminal device sends the PUSCH in the first message according to the uplink grant, thereby shortening the random access delay in the case that the preamble corresponding PUSCH occasion is invalid, avoiding the terminal device from sending at the invalid PUSCH occasion, and improving the success rate of random access.

[0141] The sending of the PUSCH in the first message refers to, for example, the sending of random access uplink configuration information carried by the PUSCH in the first message, or the sending of random access uplink configuration information. For example, the random access uplink configuration information includes device identification information (such as an international mobile equipment identity or a temporary mobile equipment identity), time synchronization information, and access priority.

[0142] Optionally, the feedback message also indicates the sending state of the SSB. Through the sending state of the SSB, the terminal device can determine whether the corresponding PUSCH occasion is valid, thereby avoiding the sending of the PUSCH on an invalid PUSCH, shortening the random access delay, and improving the random access success rate.

[0143] In some embodiments, the terminal device sends the preamble included in the first message before the configuration of the first time window. For example, the network device configures the first time window for the terminal device through a system message. As shown in FIG. 8, before step 710, step 750 is further included.

[0144] In step 750, the network device sends second system information including the first time window. Correspondingly, the terminal device receives the second system information from the network device.

[0145] By configuring the first time window, the terminal device monitors the feedback message of the network device after sending the preamble. In the case of an invalid first PUSCH occasion corresponding to the preamble, the terminal device can timely learn the uplink grant and send the PUSCH in the first message according to the uplink grant, thereby avoiding the sending of the terminal device on the invalid first PUSCH occasion corresponding to the preamble, shortening the random access delay of Type-2 RA, and improving the random access success rate.

[0146] The second system information is, for example, SIB1. For example, the first time window is added in the SIB1, and the network device indicates the first time window to the terminal device through the SIB1. Optionally, the upper-level information element of the first time window is MsgA-ConfigCommon. The second system information is the same as or different from the broadcast message. The second system information is also a unicast message or a groupcast message.

[0147] After the terminal device sends the preamble in MsgA to the network device, it waits for the time window indicated by msgA-PUSCH-TimeDomainOffset-r16 before continuing to send the PUSCH in MsgA, and then monitors the network device feedback to indicate whether the PUSCH occasion just sent is valid, which increases the random access delay or causes random access failure. The present application provides a method for the network device to indicate the uplink grant for Type-2 RA to the terminal device. That is, the network device knows whether the first PUSCH occasion corresponding to the preamble is valid, so the network device does not need to wait for the duration of the time window indicated by msgA-PUSCH-TimeDomainOffset-r16. After the network device receives the preamble, if it determines that the first PUSCH occasion corresponding to the preamble is invalid, it sends a feedback message to the terminal device indicating the uplink grant. The terminal device receives the uplink grant indicated by the network device within the first time window, that is, the terminal device has already learned the uplink grant before sending the PUSCH in the first message at the first PUSCH occasion corresponding to the preamble, and sends the PUSCH in the first message according to the uplink grant, thereby shortening the random access delay of Type-2 RA and avoiding the terminal device sending at an invalid PUSCH occasion, improving the success rate of random access.

[0148] Especially, on the NES cell, the network device itself knows the transmission state of the SSB on the cell, so after the network device receives the preamble in MsgA, it determines whether the first PUSCH occasion corresponding to the preamble is valid. In the case where the first PUSCH occasion corresponding to the preamble is invalid, the network device sends a feedback message to the terminal device indicating the uplink grant, thereby shortening the Type-2 RA delay on the NES cell.

[0149] In some embodiments, if the network device determines that the first PUSCH occasion corresponding to the preamble is valid after receiving the preamble from the terminal device, the network device will not send a feedback message within the first time window, and accordingly, the terminal device will not receive the feedback message within the first time window. The terminal device sends the PUSCH in the first message at the first PUSCH occasion corresponding to the preamble.

[0150] The terminal device in connected state triggering random access includes the following scenarios.

[0151] In the case where the network device needs to transmit downlink data to the terminal device, but the network device finds that the terminal device is in an uplink out-of-sync state, the network device will control the terminal device to initiate random access to ensure smooth data transmission.

[0152] In a case where the terminal device needs to transmit uplink data to the network device but finds that it is in an uplink out-of-sync state, the terminal device initiates random access to reestablish synchronization with the network device and transmit data.

[0153] The method of indicating the uplink grant for Type-2 RA by the network device to the terminal device is applicable not only to the terminal device in the idle state but also to the terminal device in the connected state. For example, for the terminal device in the connected state, the network device configures a new first time window for the terminal device, and the duration of the first time window is less than the interval between the preamble and the first PUSCH occasion corresponding to the preamble. After the terminal device initiates the Type-2 RA procedure and transmits the preamble in the first message to the network device, the terminal device monitors the feedback message in the first time window. After the network device receives the preamble, the network device determines that the first PUSCH occasion corresponding to the preamble is invalid, and transmits the feedback message to the terminal device in the first time window, where the feedback message indicates the uplink grant. After the terminal device receives the feedback message in the first time window, the terminal device transmits the PUSCH in the first message according to the uplink grant. For a detailed explanation, reference can be made to the above embodiments.

[0154] In addition to the above-mentioned problem of transmitting random access uplink configuration information on the invalid PUSCH by the terminal device in the idle state, for the terminal device in the connected state, after the network device provides the RRC configuration for the terminal device, the terminal device determines the valid PUSCH occasion, but currently there is no provision for the terminal device to determine the valid PUSCH occasion again after the network device dynamically starts, stops or changes the transmission pattern of the SSB on demand. Obviously, in this case, there may be ambiguity between the network device and the terminal device.

[0155] The present application provides another random access method, that is, for the terminal device in the connected state, an effective PUSCH occasion updating rule is defined. After the terminal device receives the message indicating the transmission state of the SSB, the terminal device determines the valid PUSCH occasion again after a certain time.

[0156] Here, the terminal device randomly accesses the network device is taken as an example for illustration. The terminal device and the network device establish an RRC connection, and the terminal device is in the connected state. The terminal device and the network device are, for example, the terminal and the base station shown in FIG. 1. As shown in FIG. 9, the method includes the following steps.

[0157] Step 910, the network device transmits a first message at a first time, and the first message includes the transmission state of the SSB. Correspondingly, the terminal device receives the first message from the network device.

[0158] At the first time, the network device dynamically adjusts the transmission state of the SSB, for example, starts the transmission of the SSB, stops the transmission of the SSB, or changes the transmission pattern of the SSB. Then the network device sends a first message to the terminal device. The transmission state of the SSB in the first message includes starting the transmission of the SSB, stopping the transmission of the SSB, or changing the transmission pattern of the SSB. The first message is, for example, a MAC-CE, a DCI, or an RRC reconfiguration message.

[0159] Step 920, the terminal device updates the valid PUSCH occasion at a second time, which is later than the first time.

[0160] After the terminal device receives the first message, it re-determines the validity of the PUSCH occasion, and the newly determined valid PUSCH occasion is updated from at least the second time. The second time is defined as follows.

[0161] a) The time unit of the transmission state adjustment of the SSB indicated by the first message.

[0162] b) The time unit in which the first message is located.

[0163] c) The next time unit of the time unit in which the first message is located.

[0164] Wherein, the time unit is in units of slots, subframes or symbols.

[0165] For example, as shown in FIG. 10, the first message indicates that the SSB burst period is changed from 5ms to 160ms, and the second time is defined as the next PUSCH slot of the slot in which the first message is located. The terminal device receives the first message in the fourth slot in FIG. 10, and according to the rules for determining the valid PUSCH occasion in the existing protocol, the new valid PUSCH occasion is determined from the first PUSCH slot (the sixth slot in FIG. 10) that follows. The second arrow in FIG. 10 is the second time.

[0166] In this way, in the case of dynamically starting, stopping or changing the transmission of the SSB by the network device, the concept of the second time is introduced, the terminal device redefines the process of the valid PUSCH occasion, and the potential ambiguity of the definition of the valid PUSCH occasion by the terminal device and the network device is eliminated.

[0167] It should be understood that, in order to implement the functions in the above embodiments, the network device and the terminal device comprise hardware structures and / or software modules corresponding to the functions. Those skilled in the art should easily understand that, in combination with the units and method steps of the examples described in the embodiments disclosed in the present application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in hardware or computer software driven hardware depends on the specific application scenarios and design constraints of the technical solutions.

[0168] FIG. 11 and FIG. 12 are structural schematic diagrams of possible communication apparatuses provided by the embodiments of the present application. The communication apparatuses can be used to implement the functions of the terminal device or the network device in the above method embodiments, and thus can also achieve the beneficial effects possessed by the above method embodiments. In the embodiments of the present application, the communication apparatus can be the terminal 120 as shown in FIG. 1, or the base station 110 as shown in FIG. 1, or a module (such as a chip) applied to a terminal device or a network device.

[0169] As shown in FIG. 11, the communication apparatus 1100 comprises a processing unit 1110 and a transceiver unit 1120. The communication apparatus 1100 is used to implement the functions of the terminal device or the network device in the method embodiments shown in FIG. 7, FIG. 8 and FIG. 9.

[0170] When the communication apparatus 1100 is used to implement the functions of the terminal device in the method embodiment shown in FIG. 7, the transceiver unit 1120 is used to perform steps 710, 720, 730 and 740, and the processing unit 1110 is used to determine the uplink grant according to the feedback message.

[0171] When the communication apparatus 1100 is used to implement the functions of the network device in the method embodiment shown in FIG. 7, the transceiver unit 1120 is used to perform steps 710, 720, 730 and 730, and the processing unit 1110 is used to determine that the first PUSCH occasion corresponding to the preamble is invalid.

[0172] When the communication apparatus 1100 is used to implement the functions of the terminal device or the network device in the method embodiment shown in FIG. 8, the transceiver unit 1120 is further used to perform step 750.

[0173] When the communication apparatus 1100 is used to implement the functions of the network device in the method embodiment shown in FIG. 9, the transceiver unit 1120 is used to perform step 910, and the processing unit 1110 is used to perform step 920.

[0174] For more detailed description of the processing unit 1110 and the transceiver unit 1120, reference can be made to the relevant description in the method embodiments shown in FIG. 7, FIG. 8 and FIG. 9.

[0175] As shown in FIG. 12, the communication apparatus 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It can be understood that the interface circuit 1220 can be a transceiver or an input / output interface. Optionally, the communication apparatus 1200 can further include a memory 1230 for storing instructions executed by the processor 1210 or storing input data required by the processor 1210 to execute instructions or storing data generated after the processor 1210 executes instructions. Sometimes, the interface circuit 1220 can also be understood as a part of the processor 1210, and the communication apparatus 1200 includes the processor 1210.

[0176] When the communication apparatus 1200 is used to implement the methods shown in FIG. 7, FIG. 8, and FIG. 9, the processor 1210 is configured to implement the functions of the processing unit 1110, and the interface circuit 1220 is configured to implement the functions of the transceiver unit 1120.

[0177] When the communication apparatus is a terminal chip, the terminal chip implements the functions of the terminal in the above method embodiments. The terminal chip receives information from a base station, which can be understood as that the information is first received by other modules (such as a radio frequency module or an antenna) in the terminal, and then transmitted to the terminal chip by the modules. The terminal chip transmits information to the base station, which can be understood as that the information is first transmitted to other modules (such as a radio frequency module or an antenna) in the terminal, and then transmitted to the base station by the modules.

[0178] When the communication apparatus is a base station chip, the base station chip implements the functions of the base station in the above method embodiments. The base station chip receives information from a terminal, which can be understood as that the information is first received by other modules (such as a radio frequency module or an antenna) in the base station, and then transmitted to the base station chip by the modules. The base station chip transmits information to the terminal, which can be understood as that the information is first transmitted to other modules (such as a radio frequency module or an antenna) in the base station, and then transmitted to the terminal by the modules.

[0179] In the present application, the sending of information from entity A to entity B can be directly from A to B, or indirectly from A to B via other entities. Similarly, the receiving of information from entity A by entity B can be directly from A by B, or indirectly from A by B via other entities. The entities A and B can be RAN nodes or terminals, or modules within RAN nodes or terminals. The sending and receiving of information can be the information exchange between RAN nodes and terminals, e.g., the information exchange between base stations and terminals; the sending and receiving of information can also be the information exchange between two RAN nodes, e.g., the information exchange between a CU and a DU; the sending and receiving of information can also be the information exchange between different modules within one apparatus, e.g., the information exchange between a terminal chip and other modules of the terminal, or the information exchange between a base station chip and other modules of the base station.

[0180] It can be understood that the processor in the embodiments of the present application can be a central processing unit, and can also be other general-purpose processors, digital signal processors, application-specific integrated circuits, field programmable gate arrays or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor, or any conventional processor.

[0181] The method steps in the embodiments of the present application can be implemented in hardware, or in software instructions executable by a processor. The software instructions can be composed of corresponding software modules, which can be stored in a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, a read-only optical disk, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from, and write information to, the storage medium. The storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an application-specific integrated circuit. In addition, the application-specific integrated circuit can be located in a base station or a terminal. The processor and the storage medium can also exist as discrete components in the base station or the terminal.

[0182] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments are performed. The computer can be a general purpose computer, a special purpose computer, a computer network, a network device, a user equipment or other programmable apparatus. The computer programs or instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer programs or instructions can be transferred from one website site, computer, server or data center to another website site, computer, server or data center through wired or wireless manner. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center and the like integrated with one or more available media. The available media can be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape; or an optical medium, such as a digital video disc; or a semiconductor medium, such as a solid state disk. The computer readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile storage media.

[0183] In various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be referred to each other if there is no special description and logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0184] In the present application, "at least one" means one or more, and "multiple" means two or more. The association relationship between the associated objects is described, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following cases: A exists alone, A and B exist together, B exists alone, where A and B can be singular or plural. In the literal description of the present application, the character " / ", generally represents that the associated objects before and after are in an "or" relationship; in the formula of the present application, the character " / ", represents that the associated objects before and after are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0185] It can be understood that various numerical numbers involved in the embodiments of the present application are only distinguished for convenience of description, and are not used to limit the scope of the embodiments of the present application. The size of the serial number of the above processes does not mean the execution order, and the execution order of the processes should be determined according to its function and inherent logic.

Claims

1. A random access method, characterized by, The method comprises: receiving first system information, the first system information indicating a first physical uplink shared channel (PUSCH) occasion; sending a preamble, the preamble being a preamble in a first message; receiving, within a first time window, a feedback message from a network device, the feedback message indicating an uplink grant, a duration of the first time window being less than an interval between the preamble and the first PUSCH occasion corresponding to the preamble; sending, according to the uplink grant, a PUSCH in the first message.

2. The method of claim 1, wherein, The method further comprises: receiving second system information from the network device, the second system information indicating the first time window.

3. A random access method, comprising: The method comprises: sending first system information, the first system information indicating a first physical uplink shared channel (PUSCH) occasion; receiving a preamble from a terminal device, the preamble being a preamble in a first message; in a case where the first PUSCH occasion corresponding to the preamble is invalid, sending a feedback message before the first PUSCH occasion corresponding to the preamble, the feedback message indicating an uplink grant; receiving, according to the uplink grant, a PUSCH in the first message from the terminal device.

4. The method of claim 3, wherein, The method further comprises: sending second system information, the second system information indicating the first time window.

5. The method according to any one of claims 1-4, characterized in that, The feedback message further indicates a transmission state of a synchronization signal block (SSB).

6. The method according to any one of claims 1-5, characterized in that, The feedback message is a fallback random access response.

7. A communication device, characterized by The communication device comprises a processor and an interface circuit, the interface circuit being configured to receive a signal from another communication device outside the communication device and transmit the signal to the processor or transmit a signal from the processor to the another communication device outside the communication device, and the processor is configured to implement the method according to any one of claims 1 to 6 by means of a logic circuit or executing code instructions.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program or instructions, and when the computer program or instructions are executed by a communication device, the communication device implements the method according to any one of claims 1 to 6.

9. A computer program product, characterised in that, The computer program product comprises a computer program or instructions, and when the computer program or instructions are executed by a communication device, the communication device implements the method according to any one of claims 1 to 6.

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