Method for random access, and related apparatus

Abstract

The present application provides a method for random access and an apparatus, helping to reduce the delay of initial access, thereby improving the efficiency of a terminal accessing a network. The method comprises: sending a first PRACH, wherein the first PRACH is used for requesting a SIB 1; receiving the SIB 1, wherein the SIB 1 comprises configuration information of a second PRACH; determining a first transmit power for the second PRACH on the basis of first information, wherein the first information comprises a transmit power of the first PRACH, or the first information comprises a parameter related to the transmit power of the first PRACH; and transmitting the second PRACH at the first transmit power.

Description

Method for random access and related apparatus

[0001] The present application claims priority to the Chinese patent application No. 202410857971.1, filed on June 27, 2024, and entitled "Method for random access and related apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

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

[0003] System information (SI) includes a master information block (MIB) and a system information block (SIB), wherein the SIB includes SIB 1 to SIB 21, and different SIBs correspond to configurations of different functions. The SIB 1 includes basic information required by a terminal to access a wireless cell, random access configuration, and scheduling information of other SIBs.

[0004] In order to reduce the energy consumption of the base station, a scheduling mode of on-demand SIB 1 is currently being discussed. Specifically, the base station can not broadcast the SIB 1, and only when the base station receives a request message for the SIB 1 from the terminal, the base station will broadcast the SIB 1. After receiving the SIB 1, the terminal can initiate random access based on the random access configuration included in the SIB 1.

[0005] However, the latency of initial access is large, resulting in low efficiency of terminal access to the network. SUMMARY

[0006] The present application provides a method for random access and related apparatus, which is beneficial to reduce the latency of initial access, thereby improving the efficiency of terminal access to the network.

[0007] In a first aspect, a method for random access is provided, which can be executed by a first communication apparatus. The first communication apparatus can be a terminal, a component (such as a processor, a chip, or a chip system, etc.) configured in the terminal, or a logic module or software capable of realizing all or part of the terminal functions, and the present application does not make any limitation in this regard. Hereinafter, the first communication apparatus is taken as an example of a terminal to introduce the method for random access of the present application.

[0008] The method comprises: sending a first physical random access channel (PRACH), the first PRACH being used to request a SIB 1; receiving the SIB 1, the SIB 1 comprising configuration information of a second PRACH; determining a first sending power of the second PRACH based on first information, the first information comprising a sending power of the first PRACH, or the first information comprising a parameter related to the sending power of the first PRACH; and sending the second PRACH at the first sending power.

[0009] The terminal sending the second PRACH can be understood as the terminal sending a random access preamble, and the terminal sending the second PRACH is for accessing the network. The first PRACH refers to a PRACH successfully received by the network device in a process of on-demand SIB 1 performed by the terminal before the terminal performs a random access process, that is, the terminal can receive the SIB 1 broadcast by the network device after sending the first PRACH, and then the terminal no longer sends a PRACH, and the first PRACH is the PRACH last sent by the terminal in the process of on-demand SIB 1.

[0010] The parameter related to the sending power of the first PRACH can also be described as a parameter used to determine the sending power of the first PRACH, for example, a target receiving power of the first PRACH or a power ramping counter of the first PRACH.

[0011] Based on the technical solution of the present application, the terminal determines the first sending power of the second PRACH based on the sending power of the first PRACH, or determines the first sending power of the second PRACH based on the parameter related to the sending power of the first PRACH. Since the first PRACH has been successfully sent, the terminal can also be successfully sent when sending the second PRACH based on the first information, or the number of PRACH retransmissions of the terminal can be greatly reduced, which is beneficial to reduce the latency of initial access, thereby improving the efficiency of the terminal accessing the network.

[0012] With reference to the first aspect, in some implementations of the first aspect, the first information comprises the sending power of the first PRACH. The determining of the first sending power of the second PRACH based on the first information comprises: determining the sending power of the first PRACH as the first sending power of the second PRACH.

[0013] In some implementations of the first aspect, the first information comprises a transmission power of the first PRACH. The first transmission power of the second PRACH is determined based on the first information by: determining a maximum value between the transmission power of the first PRACH and a second transmission power of the second PRACH as the first transmission power of the second PRACH, the second transmission power of the second PRACH being a transmission power determined based on configuration information of the second PRACH.

[0014] In some implementations of the first aspect, the first information comprises a parameter related to a transmission power of the first PRACH. The first transmission power of the second PRACH is determined based on the first information by: determining a target reception power of the second PRACH based on the parameter related to the transmission power of the first PRACH; and determining the first transmission power of the second PRACH based on the target reception power of the second PRACH.

[0015] In some implementations of the first aspect, the parameter related to the transmission power of the first PRACH comprises a target reception power of the first PRACH. The target reception power of the second PRACH is determined based on the parameter related to the transmission power of the first PRACH by: determining the target reception power of the first PRACH as the target reception power of the second PRACH.

[0016] In some implementations of the first aspect, the parameter related to the transmission power of the first PRACH comprises a power ramping counter of the first PRACH. The target reception power of the second PRACH is determined based on the parameter related to the transmission power of the first PRACH by: determining the target reception power of the second PRACH based on the power ramping counter of the first PRACH.

[0017] In some implementations of the first aspect, the target reception power of the second PRACH is determined based on the power ramping counter of the first PRACH by: determining an initial value of a power ramping counter of the second PRACH based on the power ramping counter of the first PRACH; and determining the target reception power of the second PRACH based on the initial value of the power ramping counter of the second PRACH.

[0018] In some implementations of the first aspect, the initial value of the power ramping counter of the second PRACH is determined based on the power ramping counter of the first PRACH by: determining a value of the power ramping counter of the first PRACH as the initial value of the power ramping counter of the second PRACH.

[0019] With reference to the first aspect, in some implementations of the first aspect, the initial value of the power ramping counter of the second PRACH is determined based on the value of the power ramping counter of the first PRACH, including: adding 1 to the value of the power ramping counter of the first PRACH to determine the initial value of the power ramping counter of the second PRACH.

[0020] With reference to the first aspect, in some implementations of the first aspect, the interval between the time when the terminal receives the SIB 1 and the time when the terminal transmits the second PRACH is less than or equal to the first time interval.

[0021] With reference to the first aspect, in some implementations of the first aspect, the interval between the time window when the terminal receives the SIB 1 and the time when the terminal transmits the second PRACH is less than or equal to the second time interval.

[0022] With reference to the first aspect, in some implementations of the first aspect, before determining the first transmission power of the second PRACH based on the first information, the method further includes: receiving indication information, the indication information being used to indicate that the terminal is allowed to determine the first transmission power of the second PRACH based on the first information.

[0023] The second aspect provides a method for random access, which can be executed by a second communication device. The second communication device can be an access network device, a component (such as a processor, a chip, or a chip system, etc.) configured in the access network device, or a logic module or software capable of realizing all or part of the functions of the access network device, and the present application does not limit the second communication device. In the following, the second communication device is taken as an access network device to introduce the method for random access of the present application.

[0024] The method includes: receiving a first PRACH, the first PRACH being used to request a SIB 1; transmitting the SIB 1, the SIB 1 including configuration information of a second PRACH; and receiving the second PRACH.

[0025] The second PRACH is transmitted by the terminal at a first transmission power, and the first transmission power is determined by the terminal based on first information. The first information includes a transmission power of the first PRACH, or the first information includes a parameter related to the transmission power of the first PRACH.

[0026] With reference to the second aspect, in some implementations of the second aspect, before receiving the second PRACH, the method further includes: transmitting indication information, the indication information being used to indicate that the terminal is allowed to determine the first transmission power of the second PRACH based on the first information.

[0027] It should be understood that the second aspect of the present application corresponds to the technical solutions of the first aspect of the present application, and the beneficial effects obtained by each aspect and the corresponding possible implementation manners are similar, and will not be repeated.

[0028] In a third aspect, a communication apparatus is provided, which includes: a module for performing the method in any possible implementation manner of any of the aspects above. Specifically, the apparatus includes a module for performing the method in any possible implementation manner of any of the aspects above.

[0029] In one design, the apparatus can include a module corresponding to each of the methods / operations / steps / actions described above in any of the aspects, which can be hardware circuit, software, or a combination of hardware circuit and software.

[0030] In another design, the apparatus is a communication chip, which can include an input circuit or interface for transmitting information or data, and an output circuit or interface for receiving information or data.

[0031] In another design, the apparatus is a terminal, which can include a transmitter for transmitting information or data, and a receiver for receiving information or data.

[0032] In another design, the apparatus is configured to perform the method in any possible implementation manner of any of the aspects above, and the apparatus can be configured in a terminal or an access network device.

[0033] In a fourth aspect, a communication apparatus is provided, which includes at least one processor configured to invoke and run a computer program from a memory, so that the apparatus performs the method in any possible implementation manner of any of the aspects above.

[0034] Optionally, the apparatus further includes a memory, which can be used to store instructions and data. The memory is coupled to the processor, and the processor executes the instructions stored in the memory, so as to implement the method described in the aspects above.

[0035] Optionally, the apparatus further includes a transmitter (transmitter) and a receiver (receiver), which can be separately arranged or integrated together, referred to as a transceiver (transceiver).

[0036] In a fifth aspect, a computer program product is provided, which includes a computer program (also referred to as code or instructions), which, when executed, causes a computer to perform the method in any possible implementation manner of any of the aspects above.

[0037] In a sixth aspect, a computer readable storage medium is provided, which stores a computer program (also referred to as code or instructions) that, when executed on a computer, causes the computer to perform the method in any possible implementation of any of the aspects above.

[0038] In a seventh aspect, a chip system is provided, which includes at least one processor configured to support the functions involved in any possible implementation of any of the aspects above, such as receiving or processing data involved in the methods above.

[0039] In a possible design, the chip system further includes a memory configured to store program instructions and data, and the memory is located in or out of the processor.

[0040] Optionally, the chip system can be composed of a chip, or can include a chip and other discrete devices. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a schematic diagram of an architecture of a communication system suitable for embodiments of the present application;

[0042] FIG. 2 is a schematic diagram of a flow of a four-step contention-based random access method;

[0043] FIG. 3 is a schematic diagram of a structure of a MAC PDU composed of MAC RARs;

[0044] FIG. 4 is a schematic diagram of a structure of a MAC RAR;

[0045] FIG. 5 is a schematic diagram of a flow of a two-step contention-based random access method;

[0046] FIG. 6 is a schematic diagram of a flow of a method of on-demand SIB 1;

[0047] FIG. 7 is a schematic diagram of a flow of a method for random access provided by embodiments of the present application;

[0048] FIGS. 8 and 9 are schematic block diagrams of communication apparatuses provided by embodiments of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0050] Before introducing the method for random access and related apparatus provided by embodiments of the present application, the following points are explained.

[0051] First, in the embodiments shown below, each term and English abbreviation, such as wake-up signal, WUS, PRACH, and the like, are exemplary examples given for the convenience of description, and should not constitute any limitation on the present application. The present application does not exclude the possibility of defining other terms capable of achieving the same or similar functions in existing or future protocols.

[0052] Second, in the embodiments shown below, the first, second, and various numerical numbers are only for the convenience of description, and do not limit the scope of the embodiments of the present application.

[0053] Third, "at least one" means one or more, and "multiple" means two or more. The association relationship of "and / or" describing the associated objects indicates that there can be three relationships, for example, A and / or B can represent the following cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, and c can represent: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0054] Fourth, "sending" and "receiving" in the present application represent the direction of signal transmission. For example, "sending UL WUS to the access network device" can be understood as that the destination of the UL WUS is the access network device, which can include direct transmission through the air interface, and also includes indirect transmission through the air interface by other units or modules. "Receiving UL WUS from the terminal" can be understood as that the source of the UL WUS is the terminal, which can include direct reception from the terminal through the air interface, and also can include indirect reception from the terminal through the air interface from other units or modules. "Sending" can also be understood as "output" of the chip interface, and "receiving" can also be understood as "input" of the chip interface.

[0055] In other words, sending and receiving can be between devices, for example, between a terminal and an access network device; or can be within a device, for example, between components, modules, chips, software modules or hardware modules within a device through a bus, wire or interface.

[0056] Figure 1 is a schematic diagram of an architecture of a communication system suitable for embodiments of the present application. The communication system 1000 shown in Figure 1 comprises a radio access network (RAN) 100 and a core network 101. Optionally, the communication system 1000 further includes an Internet 102. The radio access network 100 can include at least one access network device (e.g. 110a and 110b in Figure 1) and at least one terminal (e.g. 120a-120j in Figure 1). The terminal is connected to the access network device by wireless means and the access network device is connected to the core network 101 by wireless or wired means. The core network device and the access network device can be independent and different physical devices, or the functions of the core network device and the logical functions of the access network device can be integrated on the same physical device, or a physical device can integrate the functions of part of the core network device and part of the access network device. Terminals and terminals, and access network devices and access network devices can be connected to each other by wired or wireless means. Figure 1 is only a schematic diagram, and the communication system can also include other access network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1.

[0057] The radio access network 100 can be a 3rd generation partnership project (3GPP) related cellular system, for example, a 4th generation mobile communication technology (4G) system (also referred to as a long term evolution (LTE) system), a 5th generation mobile communication technology (5G) system (also referred to as a new radio (NR) system), or can also be applied to future mobile communication systems, and the specific implementation is not limited. The radio access network 100 can also be an open radio access network (open RAN, O-RAN or ORAN), a cloud radio access network (CRAN). The radio access network 100 can also be a non-terrestrial network (NTN), a satellite communication network, a high altitude platform station (HAPS) communication network, an integrated access and backhaul (IAB) communication network, a reconfigurable intelligent surface (RIS) communication network, etc. The radio access network 100 can also be a communication system in which two or more of the above systems are fused.

[0058] The access network device is a node in the radio access network, which can also be referred to as a RAN node, and can also be referred to as a RAN device. The access network device is used to help the terminal to realize wireless access. The plurality of access network devices in the communication system 1000 can be nodes of the same type or nodes of different types.

[0059] In a possible scenario, the access network device can be a base station, an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting point (TP), a next generation NodeB (gNB), a next generation base station in a 6G mobile communication system, a base station in a future mobile communication system, an access point (AP) in a satellite, an integrated access backhaul (IAB) node, an access network device in a mobile switching center non-terrestrial network (NTN) communication system, i.e., can be deployed in a high-altitude platform or a satellite, etc. The access network device can be a macro base station (such as 110a in FIG. 1), a micro base station or an indoor station (such as 110b in FIG. 1), a relay node or a donor node, or a wireless controller in a CRAN scenario. The access network device can also be a device assuming a base station function in device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, unmanned aircraft communication, or machine communication. Alternatively, the access network device can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in the V2X technology can be a road side unit (RSU).

[0060] In another possible scenario, multiple access network devices cooperate to assist a terminal to implement wireless access, and different access network devices respectively implement part of the functions of a base station. For example, the access network device can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH). It can be understood that the access network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into an access network device in a radio access network (RAN), or the CU can be divided into an access network device in a core network, which is not limited here.

[0061] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an O-RAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0062] A terminal is a device with wireless transceiving function, which can send signals to an access network device or receive signals from the access network device. The terminal can also be referred to as a terminal device, a terminal equipment, a user equipment (UE), a mobile station, a mobile terminal, etc. The terminal can be widely applied to various scenarios, such as D2D, V2X communication, machine-type communication (MTC), internet of things (IOT), 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. The terminal can specifically be a mobile phone, a tablet computer, a computer with wireless transceiving function, a wearable device, a vehicle, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc. The embodiments of this application do not limit the specific technology and specific device form adopted by the terminal.

[0063] The access network device and the terminal can be fixed in position or movable. The access network device and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; can also be deployed on an airplane, a balloon and a man-made satellite. The embodiments of this application do not limit the application scenarios of the access network device and the terminal.

[0064] The roles of the access network device and the terminal can be relative. For example, the helicopter or the drone 120i in FIG. 1 can be configured as a mobile access network device, and for the terminal 120j that accesses the wireless access network 100 through 120i, 120i is an access network device; but for the access network device 110a, 120i is a terminal, that is, 110a communicates with 120i through a wireless air interface protocol. Of course, 110a and 120i can also communicate through an interface protocol between access network devices, and in this case, 120i is also an access network device relative to 110a. Therefore, the access network device and the terminal can be collectively referred to as a communication apparatus, and 110a and 110b in FIG. 1 can be referred to as a communication apparatus with an access network device function, and 120a-120j in FIG. 1 can be referred to as a communication apparatus with a terminal function.

[0065] The access network device and the terminal, the access network device and the access network device, and the terminal and the terminal can communicate through a licensed spectrum, or through an unlicensed spectrum, or through both the licensed spectrum and the unlicensed spectrum; can communicate through a spectrum below 6 gigahertz (GHz), or through a spectrum above 6 GHz, or through both the spectrum below 6 GHz and the spectrum above 6 GHz. The embodiments of the present application do not limit the spectrum resources used for wireless communication.

[0066] In the embodiments of the present application, the functions of the access network device can also be performed by a module (such as a chip) in the access network device, or by a control subsystem containing an access network device function. The control subsystem containing an access network device function 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 a terminal function.

[0067] The related technologies and concepts involved in the present application are introduced as follows.

[0068] 1. Random access (RA)

[0069] The random access procedure refers to a procedure from sending a random access preamble by a terminal to establishing a basic signaling connection with a network before the terminal accesses the network. The purpose of random access design is to synchronize the terminal with the access network device in uplink, and the access network device allocates uplink resources for the terminal. In the random access procedure, the terminal needs to initiate access on a specific PRACH time-frequency resource. The signal sent by the terminal when initiating access is a random access preamble, which is used to indicate that the access network device has a random access request, so that the access network device can estimate the transmission delay between the terminal and the access network device. Among them, PRACH is closely related to random access channel (RACH), and PRACH is used to carry the communication requirements of RACH.

[0070] At present, random access includes a contention-based random access mechanism. For contention-based random access, the terminal randomly selects a random access preamble in the random access preamble configured by SIB 1. In this way, there may be a situation that multiple terminals select the same random access preamble, thereby causing a random access preamble collision problem. Since the access network device cannot distinguish the random access preambles sent by different terminals, the terminal needs to send a message related to itself to the access network device, so that the access network device can distinguish the random access preambles sent by different terminals.

[0071] The contention-based random access mechanism includes four-step random access and two-step random access. The following describes the two different random access methods.

[0072] FIG. 2 is a flowchart of a four-step contention-based random access method 200. As shown in FIG. 2, the method 200 includes S201 to S204, and the specific steps are as follows:

[0073] S201, the terminal sends a random access preamble to the access network device. Correspondingly, the access network device receives the random access preamble.

[0074] This step can also be referred to as transmission of message 1, or transmission of PRACH, that is, the terminal sends PRACH to the access network device. The initial random access is initiated by the media access control (MAC) layer of the terminal. Before S201, the access network device can notify all terminals which PRACH resources are allowed to transmit random access preambles.

[0075] After receiving the random access preamble, the access network device acquires a random access preamble identifier (RAPID) and a downlink transmission beam by detecting the random access preamble, and estimates a transmission delay between the terminal and the access network device.

[0076] In S202, the access network device sends a random access response (RAR) to the terminal. Accordingly, the terminal receives the random access response.

[0077] This step can also be referred to as transmission of message 2.

[0078] The access network device sends the random access response through a physical downlink shared channel (PDSCH), and one PDSCH can carry the random access response sent to multiple terminals. The random access response includes but is not limited to: a RAPID, a backoff indicator (BI), and a MAC RAR. The MAC RAR includes but is not limited to: a timing advance (TA), an uplink grant (UL grant), and a temporary cell-radio network temporary identity (TC-RNTI), and the uplink grant is used to schedule physical uplink shared channel (PUSCH) transmission.

[0079] FIG. 3 is a structure diagram of a MAC protocol data unit (PDU) composed of a MAC RAR. Referring to FIG. 3, the MAC PDU includes multiple MAC PDU subunits (MAC subPDU) and optional padding bits, for example, as shown in FIG. 3, the MAC PDU includes n MAC PDU subunits.

[0080] Among them, the MAC PDU subunit 1 has only BI (BI only), and the MAC subheader of the MAC PDU subunit 1 includes five fields (E / T / R / R / BI), wherein E is an extension field, used to indicate whether there are other fields in the MAC subheader; T is a type field, used to indicate whether the MAC subheader includes a RAPID or a BI; R is a reserved field, usually set to "0"; BI is used to indicate the time range that the terminal needs to wait before retransmitting the random access preamble.

[0081] The MAC PDU subunit 2 has RAPID (RAPID only), and the MAC subheader of the MAC PDU subunit 2 includes three fields (E / T / RAPID).

[0082] Each of the MAC PDU subunits 3 to n includes a MAC subheader composed of three fields (E / T / RAPID) and a payload (MAC RAR). The structure of the MAC RAR is shown in FIG. 4, which includes four fields: R, a timing advance command, an uplink grant, and a TC-RNTI.

[0083] As can be seen from the structure of the MAC PDU, if the access network device detects random access requests from multiple terminals on the same PRACH resource (the same RA-RNTI), the access network device can use one MAC PDU to respond to the random access requests of the multiple terminals, and each response to a random access request corresponds to one RAR.

[0084] After the terminal sends the message 1, it monitors the physical downlink control channel (PDCCH) and waits for the arrival of the random access response in the RAR window. Specifically, if the RAPID received by the terminal in the RAR window is the same as the RAPID sent by the terminal in the message 1, the response is successful, and then the terminal can send uplink scheduling information to the access network device. If the terminal does not receive a response to the message 1 within the RAR window or fails to verify the response to the message 1, the response fails. In this case, if the number of random access attempts is less than the upper limit, the terminal continues to send the random access preamble to reinitiate the random access, and if the number of random access attempts reaches the upper limit, the random access fails.

[0085] S203, the terminal sends uplink scheduling information to the access network device. Accordingly, the access network device receives the uplink scheduling information.

[0086] This step can also be referred to as the transmission of message 3. The message 3 is carried on the PUSCH and includes a contention resolution identifier, a cell-radio network temporary identity (C-RNTI) MAC control element (CE), or a common control channel (CCCH) service data unit (SDU).

[0087] After the terminal sends the uplink scheduling information, a contention resolution timer is started to count.

[0088] When PUSCH transmission fails, i.e. the access network device fails to receive the PUSCH, the access network device can use a downlink control information (DCI) scrambled by a TC-RNTI to schedule a retransmission of the PUSCH.

[0089] S204, the access network device sends contention resolution information to the terminal. Correspondingly, the terminal receives the contention resolution information.

[0090] This step can also be referred to as the transmission of message 4. The access network device uses C-RNTI on PDCCH or contention resolution identity on PUSCH to help the terminal to resolve contention.

[0091] The terminal continues to monitor PDCCH before the contention resolution timer expires, and considers contention resolution successful and stops counting when any of the following conditions is met:

[0092] (1) The terminal receives a PDCCH scrambled by C-RNTI.

[0093] (2) The terminal receives a PDCCH scrambled by TC-RNTI, and the MAC PDU is successfully decoded. Specifically, the contention resolution identity received by the terminal through PDSCH is the same as the contention resolution identity carried in the message 3 sent by the terminal.

[0094] If any of the above conditions is not met before the contention resolution timer expires, the terminal considers contention resolution to fail. In this case, if the number of random access attempts does not reach the upper limit, the terminal initiates random access again, and if the number of random access attempts reaches the upper limit, the random access fails.

[0095] Figure 5 is a schematic flowchart of a contention-based two-step random access method 500. As shown in Figure 5, the method 500 includes S501 and S502, and the specific steps are as follows:

[0096] S501, the terminal sends message A to the access network device. Correspondingly, the access network device receives message A.

[0097] Wherein, message A can be regarded as a message after message 1 and message 3 in the above four-step random access process are packaged, in other words, message A includes message 1 and message 3 in the above four-step random access process, i.e. includes PRACH and PUSCH.

[0098] S502, the access network device sends message B to the terminal. Correspondingly, the terminal receives message B.

[0099] Wherein, the message B can be regarded as the message 4 in the above four-step random access procedure, in other words, the message B includes the equivalent content of the message 4 in the above four-step random access procedure, i.e. the contention resolution information.

[0100] In the above random access procedure, the access network device can not receive the PRACH or the contention resolution fails, then the terminal needs to increase the transmission power of the PRACH to resend the PRACH, so as to increase the success rate of random access. The transmission power of the PRACH satisfies the following formula: P PRACH,b,f,c (i) = min{P CMAX,f,c (i), P PRACH,target,f,c + PL b,f,c}[dBm]

[0101] Wherein, P PRACH,b,f,c (i) represents the transmission power of the PRACH on the active bandwidth part (BWP) b of the carrier f of the cell c at the transmission occasion i. P CMAX,f,c (i) represents the maximum output power configured for the terminal at the transmission occasion i of the cell c (hereinafter referred to as the maximum output power of the terminal). PRACH,target,f,c represents the target received power of the PRACH of the carrier f of the cell c (hereinafter referred to as the target received power of the PRACH), which can be understood as the power expected to be received by the access network device. PL b,f,c is the path loss (hereinafter referred to as the path loss) obtained based on the downlink reference signal (RS) associated with the PRACH transmission on the active downlink BWP of the carrier f of the cell c.

[0102] The target received power of the PRACH P PRACH,target,f,c is denoted as PREAMBLE_RECEIVED_TARGET_POWER, which satisfies the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preeambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER-1) x PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA

[0103] Wherein, preeambleReceivedTargetPower represents the target received power of the initial random access preamble (which can be referred to as the initial preamble target received power), or the initial target received power of the PRACH, which is configured by the base station for the terminal.

[0104] The DELTA_PREAMBLE needs to be determined according to a preamble format. For example, the terminal obtains an index of a PRACH configuration from SIB 1, and then the terminal determines the preamble format according to the index of the PRACH configuration. If the preamble is a long format, the value of DELTA_PREAMBLE can be determined by Table 1 below; if the long preamble is a short format, the value of DELTA_PREAMBLE can be determined by Table 2 below, where μ is a subcarrier spacing, which can be determined according to the “msg1-SubcarrierSpacing” parameter in SIB 1, and the value can be 0, 1, 2, 3, 4, 5, or 6.

[0105] Table 1

[0106] Table 2

[0107] The PREAMBLE_POWER_RAMPING_STEP represents a power ramping step of a random access preamble (which can be referred to as a preamble power ramping step), which can be understood as that the transmission power of the PRACH is increased by a value corresponding to the preamble power ramping step for each retransmission of the PRACH.

[0108] The PREAMBLE_POWER_RAMPING_COUNTER represents a power ramping counter of a random access preamble (which can be referred to as a preamble power ramping counter), which can be understood as being used to count the number of transmissions of the random access preamble, and the initial value is 1. Each increase of 1 of the counter means that the transmission power of the PRACH is increased by a value corresponding to the PREAMBLE_POWER_RAMPING_STEP.

[0109] The POWER_OFFSET_2STEP_RA represents a power offset of two-step random access. If the type of random access is changed from two-step random access to four-step random access, the POWER_OFFSET_2STEP_RA satisfies the following formula: POWER_OFFSET_2STEP_RA = (PREAMBLE_POWER_RAMPING_COUNTER - 1) x (MSGA_PREAMBLE_POWER_RAMPING_STEP - PREAMBLE_POWER_RAMPING_STEP)

[0110] Wherein, the MSGA_PREAMBLE_POWER_RAMPING_STEP represents a power ramping step of a random access preamble of message A, and the introduction of other parameter items can refer to the description in the foregoing, which will not be described herein.

[0111] 2. On-demand SIB 1

[0112] In order to reduce the energy consumption of a cell, when there is no or few terminals to be served in the cell, the cell will enter an energy saving state, becoming a network energy saving (NES) cell. In this energy saving state, the base station of the cell can stop broadcasting synchronization signal block (SSB) or SIB 1 in the cell or keep very few transmission of SSB or SIB 1. However, the NES cell should start in time when it is needed to provide service to a terminal, because without normal transmission of SSB or SIB 1, the terminal cannot be served. Therefore, on-demand SIB 1 is currently discussed, which can be understood as that the base station does not broadcast SIB 1 by default to save the energy consumption of the base station, and only sends SIB 1 when receiving a request for SIB 1 from a terminal.

[0113] FIG. 6 is a schematic flowchart of a method 600 of on-demand SIB 1. The method 600 includes the interaction among a cell A, a cell B and a terminal, wherein the cell B is an NES cell, for example, when the load of the cell B is empty or low, the cell B enters an energy saving state and becomes an NES cell.

[0114] The method 600 includes S601 to S604, and the specific steps are as follows:

[0115] S601. The cell A sends configuration information of an uplink wake up signal (UL WUS) to the terminal. Correspondingly, the terminal receives the configuration information of the UL WUS.

[0116] The configuration information of the UL WUS includes transmission resources of the UL WUS, etc. The UL WUS is, for example, a PRACH, that is, the cell A can indicate a PRACH resource to the terminal.

[0117] The UL WUS is used for the wake up of the base station, for example, to support the wake up of the base station in a sleep power state / energy saving state (for example, SSB-free / SIB 1-free / SSB relaxed state).

[0118] S602. The terminal sends the UL WUS to the cell B. Correspondingly, the cell B receives the UL WUS.

[0119] S603. The cell B sends SIB 1. Correspondingly, the terminal receives the SIB 1.

[0120] Optionally, before S603, the method 600 further includes S604: the cell B sends a random access response to the terminal. Correspondingly, the terminal receives the random access response.

[0121] Based on the above description, in the on-demand SIB 1 procedure, the terminal sends a PRACH to the access network device, and this time the PRACH is sent to request the SIB 1. After receiving the SIB 1, the terminal can initiate a random access procedure based on the service requirement. In the random access procedure, the terminal sends a PRACH to the access network device again, and this time the PRACH is sent to request access to the network.

[0122] It should be noted that the terminal sending the UL WUS in the present application can be regarded as sending the PRACH.

[0123] In the on-demand SIB 1 procedure, the terminal is in an idle state or an inactive state. After the terminal receives the SIB 1, if the terminal needs to enter a connected state for data transmission, the terminal will perform a random access procedure to enter the connected state.

[0124] Currently, the time delay from the terminal sending the UL WUS to the completion of the random access is large, which is because: when the terminal starts to send the UL WUS to request the SIB 1, the terminal obtains the transmission power of the UL WUS by using the above formula for calculating the transmission power of the PRACH, and sends the UL WUS at the transmission power of the UL WUS. At the beginning of sending the UL WUS, the transmission power is relatively small, and the access network device may not be able to successfully receive the PRACH, therefore, the terminal needs to increase the transmission power of the UL WUS, for example, the preamble power ramping counter in the above formula is increased by 1 each time to increase the transmission power of the UL WUS, until the access network device successfully receives the UL WUS, which results in a large time delay from the terminal sending the UL WUS to receiving the SIB 1. After the terminal receives the SIB 1, when the terminal sends the message 1 or the message A in the random access procedure, similar to sending the UL WUS, the terminal still needs to start sending the PRACH from a small transmission power, until the PRACH is successfully sent, which results in a large initial access time delay of the terminal, thereby resulting in a low efficiency of the terminal accessing the network.

[0125] Therefore, the embodiments of the present application provide a method for random access, which can associate the transmission power of the PRACH in the random access procedure with the transmission power of the UL WUS in the on-demand SIB 1 procedure, to reduce the retransmission times of the PRACH, thereby reducing the initial access time delay of the terminal, and further improving the efficiency of the terminal accessing the network.

[0126] FIG. 7 is a schematic diagram of a method 700 for random access, steps of the method 700 are performed by interaction of a terminal and an access network device, the terminal is, for example, any of 120a-120j shown in FIG. 1, and the access network device is, for example, 110a or 110b shown in FIG. 1, but the present application does not make any limitation in this regard.

[0127] The method 700 includes S701-S704, and optionally, the method 700 further includes S705, and specific steps are as follows:

[0128] S701, the terminal sends a first PRACH to the access network device, and the first PRACH is used to request SIB 1. Correspondingly, the access network device receives the first PRACH.

[0129] The first PRACH can be regarded as a wake-up signal used to wake up the access network device. Before the terminal sends the first PRACH, the access network device is in an energy-saving state (or a sleep state, or an inactive state) and does not broadcast SIB 1. In some scenarios, for example, when the terminal moves into the coverage area of the access network device, the terminal can send a wake-up signal, i.e., the first PRACH, to the access network device to wake up the access network device in the energy-saving state.

[0130] The first PRACH is used to request SIB 1, and can also be described as the first PRACH is used to wake up the access network device, or the first PRACH is used to activate the access network device.

[0131] S702, the access network device sends SIB 1. Correspondingly, the terminal receives SIB 1.

[0132] The SIB 1 includes configuration information of the second PRACH, and the configuration information of the second PRACH includes time domain resources and / or frequency domain resources of the second PRACH, a subcarrier spacing of the second PRACH, a root sequence index, and the like, and further includes power parameters of the second PRACH, such as an initial target received power of the second PRACH, a power ramping step of the second PRACH, and the like.

[0133] After receiving the first PRACH, the access network device broadcasts SIB 1. It can be understood that the access network device switches from the energy-saving state to the normal running state, or the activated state, or the wake-up state.

[0134] S703, the terminal determines a first transmission power of the second PRACH based on first information. The first information includes a transmission power of the first PRACH, or the first information includes a parameter related to the transmission power of the first PRACH.

[0135] The second PRACH is used for random access, or used for accessing a network, or used for indicating an access request, or used for initial access, or used for establishing a radio resource control (RRC) connection, or used for reestablishing an RRC connection, or used for resuming an RRC connection, or used for requesting other SI, or used for small data transmission (SDT), or used for uplink synchronization, etc. However, the second PRACH is not used for requesting SIB 1.

[0136] As described above, before performing the random access procedure, the terminal needs to perform the on-demand SIB 1 procedure to obtain SIB 1, and then obtain the configuration information of the PRACH used for random access.

[0137] The first PRACH is a PRACH sent by the terminal before the second PRACH is sent, for requesting SIB 1, and the terminal receives SIB 1. Since in the on-demand SIB 1 procedure, the terminal may need to retransmit the PRACH to increase the transmission power of the PRACH until the access network device successfully receives the PRACH, after successfully receiving the PRACH, the access network device broadcasts SIB 1, and after receiving SIB 1, the terminal no longer sends the first PRACH. Therefore, the first PRACH can be regarded as the PRACH last sent by the terminal in the on-demand SIB 1 procedure, or the PRACH most recently sent by the terminal for requesting SIB 1 before receiving SIB 1.

[0138] For example, in the on-demand SIB 1 procedure, the terminal first sends a PRACH to the access network device to request SIB 1, and then the terminal receives SIB 1, so the first PRACH is the PRACH first sent by the terminal.

[0139] For example, in the on-demand SIB 1 procedure, the terminal first sends a PRACH, and then the terminal does not receive SIB 1, or the terminal does not receive a RAR, or the PRACH sent this time is not received by the access network device, therefore, the terminal secondly sends a PRACH, the PRACH sent this time is successfully received by the access network device, and then the terminal receives SIB 1, so the first PRACH is the PRACH secondly sent by the terminal.

[0140] The on-demand SIB 1 procedure can also be understood as a random access procedure for requesting SIB 1. After the on-demand SIB 1 procedure ends, the terminal can perform a subsequent random access procedure to access the network and perform normal data transmission.

[0141] The second PRACH can be understood as the PRACH that is transmitted for the first time after the terminal receives the SIB 1.

[0142] The first transmission power of the second PRACH, for example, is the initial transmission power of the second PRACH in the random access procedure. The first transmission power of the second PRACH can also be understood as the power of the PRACH that is transmitted for the first time after the terminal receives the SIB 1.

[0143] In a possible implementation, the first information includes the transmission power of the first PRACH, that is, the terminal determines the first transmission power of the second PRACH based on the transmission power of the first PRACH.

[0144] In an example, S703 includes that the terminal determines the transmission power of the first PRACH as the first transmission power of the second PRACH. In this way, since the first PRACH has been successfully received by the access network device (because the terminal has received the SIB 1), it is very likely that the second PRACH will also be successfully received by the access network device if the terminal determines the transmission power of the first PRACH as the first transmission power of the second PRACH, so that retransmission is not needed. Even if retransmission is needed, for example, the access network device does not receive the second PRACH, the access network device will perform power ramping based on the first transmission power to increase the power of the PRACH. The terminal does not need to start trying to transmit the second PRACH from a smaller transmission power (for example, start trying to transmit the second PRACH from a preamble power ramping counter of 1), which is conducive to reducing the number of times the terminal retransmits the PRACH, and is conducive to reducing the latency of initial access, thereby improving the efficiency of the terminal accessing the network.

[0145] In another example, S703 includes that the terminal determines a second transmission power of the second PRACH, and the terminal compares the second transmission power with the transmission power of the first PRACH, and determines the maximum of the two as the first transmission power of the second PRACH. Or it can be understood in this way: if the second transmission power of the second PRACH is less than the transmission power of the first PRACH, the first transmission power of the second PRACH is equal to the transmission power of the first PRACH. Otherwise, the first transmission power of the second PRACH is equal to the second transmission power of the second PRACH. Wherein, the second transmission power of the second PRACH is a transmission power determined based on the configuration information of the second PRACH, for example, the initial target reception power of the second PRACH, the power ramping step of the second PRACH, and other parameters are used to determine P PRACH,target,f,c Then, according to the formula P PRACH,b,f,c (i) = min{P CMAX,f,c (i), P PRACH,target,f,c + PLb,f,c} [dBm], determine a first transmit power of the second PRACH.

[0146] In another example, the first transmit power of the second PRACH satisfies max{P CMAX,f,c (i), P1-P2+P3}, where P CMAX,f,c (i) is the maximum output power of the terminal, P1 is the transmit power of the first PRACH, P2 is the measured path loss when the transmit power of the first PRACH is determined before, and P3 is the currently measured path loss.

[0147] In another possible implementation, the first information comprises a parameter related to the transmit power of the first PRACH, and S703 comprises: determining, by the terminal, a target receive power of the second PRACH based on the parameter related to the transmit power of the first PRACH; and determining, by the terminal, the first transmit power of the second PRACH based on the target receive power of the second PRACH.

[0148] From the above formula of the transmit power of the PRACH, it can be seen that the transmit power of the PRACH is equal to min{P CMAX,f,c (i), P PRACH,target,f,c +PL b,f,c}, that is, the minimum value of P CMAX,f,c (i) and P PRACH,target,f,c +PL b,f,c is taken, where P CMAX,f,c (i) is the maximum output power of the terminal, P PRACH,target,f,c is the target receive power of the PRACH, and PL b,f,c is the path loss. After the terminal determines the target receive power of the second PRACH based on the parameter related to the transmit power of the first PRACH, that is, P PRACH,target,f,c , the first transmit power of the second PRACH can be determined according to the formula. Specifically, the sum of the target receive power of the second PRACH and the path loss, that is, P PRACH,target,f,c +PL b,f,c , can be calculated, and the sizes of P CMAX,f,c (i) and P PRACH,target,f,c +PL b,d,c are compared, so as to determine the first transmit power of the second PRACH.

[0149] The following describes how the terminal determines the target receive power of the second PRACH based on the parameter related to the transmit power of the first PRACH.

[0150] In a possible implementation, the parameter related to the transmission power of the first PRACH includes: a target received power of the first PRACH, denoted as PfirstPRACH,target,f,c.

[0151] The terminal determines the target received power of the second PRACH based on the parameter related to the transmission power of the first PRACH, denoted as PsecondPRACH,target,f,c, including: the terminal determines the target received power of the first PRACH as the target received power of the second PRACH. It can be understood that PsecondPRACH,target,f,c = PfirstPRACH,target,f,c.

[0152] For example, when the terminal determines the target received power of the second PRACH by using the above formula of the target received power of the PRACH, an offset value can be added in the formula to make the target received power of the second PRACH equal to the target received power of the first PRACH.

[0153] Optionally, PsecondPRACH,target,f,c = max(PfirstPRACH,target,f,c, T). T is a target received power determined according to the configuration parameter of the second PRACH, for example: T = preeambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER-1) x PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA.

[0154] Optionally, the target received power PsecondPRACH,target,f,c of the second PRACH can also be determined based on the configuration information of the second PRACH carried in the SIB 1, in combination with the formula of the target received power of the PRACH shown in the above, but at the same time, PsecondPRACH,target,f,c ≥ PfirstPRACH,target,f,c is met. Specifically, it can be: PsecondPRACH,target,f,c = preeambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER-1) x PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA

[0155] The value (which can be understood as an initial value) of the PREAMBLE_POWER_RAMPING_COUNTER is a minimum positive integer satisfying that the target received power PsecondPRACH,target,f,c of the second PRACH is not less than the target received power PfirstPRACH,target,f,c of the first PRACH. For example, the target received power of the second PRACH is calculated from the value of the power ramping counter of the second PRACH being 1, until the calculated target received power of the second PRACH is not less than the target received power of the first PRACH, and then the terminal can calculate the first transmission power of the second PRACH based on the target received power of the second PRACH that satisfies the power constraint condition for the first time. The target received power of the second PRACH that satisfies the power constraint condition for the first time can be understood as the minimum value of the target received powers of the second PRACH that satisfy the power constraint condition. The power constraint condition is that the target received power of the second PRACH is not less than the target received power of the first PRACH.

[0156] In another possible implementation, the parameter related to the transmission power of the first PRACH includes a power ramping counter of the first PRACH. The terminal determines the target received power of the second PRACH based on the parameter related to the transmission power of the first PRACH, including that the terminal determines the target received power of the second PRACH based on the power ramping counter of the first PRACH.

[0157] Optionally, the terminal determines the target received power of the second PRACH based on the power ramping counter of the first PRACH, including that the terminal determines an initial value of a power ramping counter of the second PRACH based on the power ramping counter of the first PRACH, and the terminal determines the target received power of the second PRACH according to the initial value of the power ramping counter of the second PRACH.

[0158] In one example, the terminal determines the value of the power ramping counter of the first PRACH as the initial value of the power ramping counter of the second PRACH, and then the terminal can determine the target received power of the second PRACH based on the above formula for calculating the target received power of the PRACH.

[0159] In another example, the terminal determines the initial value of the power ramping counter of the second PRACH as the value of the power ramping counter of the first PRACH plus M, and then the terminal can determine the target received power of the second PRACH based on the above formula for calculating the target received power of the PRACH. It can be understood that the initial value of the power ramping counter of the second PRACH is determined according to the value of the power ramping counter of the first PRACH, for example, the initial value (for example, denoted as X) of the power ramping counter of the second PRACH = the value (for example, denoted as Y) of the power ramping counter of the first PRACH + M, where M can be a non-negative integer, for example, equal to 0, 1, 2, etc.

[0160] In S704, the terminal transmits the second PRACH at the first transmission power. Correspondingly, the access network device receives the second PRACH.

[0161] After determining the first transmission power of the second PRACH according to S703, the terminal can start the PRACH transmission in the random access procedure, that is, transmit the message 1 or the message A. The terminal can transmit the PRACH on the PRACH resource configured by the access network device. The PRACH resource is, for example, a time domain resource and / or a frequency domain resource. The second PRACH can be the PRACH in the 4-step random access or the PRACH in the 2-step random access.

[0162] In the embodiments of the present application, the terminal determines the first transmission power of the second PRACH based on the first information, which is beneficial to improve the access success rate of the second PRACH, reduce the retransmission times of the second PRACH, and thus reduce the time delay of the initial access of the terminal, and further improve the efficiency of the terminal accessing the network.

[0163] Optionally, the terminal can enable the method provided in the embodiments of the present application to determine the first transmission power of the second PRACH when the applicable condition is met. The applicable condition is introduced as follows.

[0164] In a possible implementation, the interval between the time when the terminal receives the SIB 1 and the time when the terminal transmits the second PRACH is less than or equal to the first time interval. In other words, when the interval between the time when the terminal receives the SIB 1 and the time when the terminal is about to transmit the second PRACH is less than or equal to the first time interval, the terminal uses the method provided in the embodiments of the present application, that is, the terminal determines the first transmission power of the second PRACH based on the first information. Otherwise, the terminal can determine the transmission power of the second PRACH according to the existing scheme.

[0165] In one example, the time when the terminal receives the SIB 1, the time when the terminal transmits the second PRACH, and the time interval can be at a slot level, or in other words, in units of slots. For example, the first time interval is 2 slots, the terminal receives the SIB 1 at slot 1, and transmits the second PRACH at slot 2, the interval between slot 1 and slot 2 is 1 slot, which is less than the first time interval, and therefore, the terminal can determine the first transmission power of the second PRACH using the method provided in the embodiments of the present application. The slot 1 is, for example, the starting slot occupied by the reception of the SIB 1, or the ending slot occupied by the reception of the SIB 1. Alternatively, the terminal receives the SIB 1 at slot m, the first time interval is n slots, the terminal transmits the second PRACH at slot q, and q is less than or equal to m+n, the terminal can determine the first transmission power of the second PRACH using the method provided in the embodiments of the present application, that is, based on the first information. The m, n, and q are all non-negative integers. The first time interval can be pre-defined by a protocol or configured by the access network device. Alternatively, it can also be understood that the length of the first time interval can be pre-defined by a protocol or configured by the access network device.

[0166] In another example, the time when the terminal receives the SIB 1, the time when the terminal transmits the second PRACH, and the time interval can be at a subframe level, a radio frame level, or in other words, in units of subframes or radio frames.

[0167] In one possible implementation, before the expiration of the timer or before the counter exceeds the threshold, the terminal can determine the first transmission power of the second PRACH based on the first information using the method provided in the embodiments of the present application. The terminal starts the timer or the counter when the terminal receives the SIB 1.

[0168] In another possible implementation, the RACH occasion (RO) for the terminal to transmit the second PRACH is the Nth RO after the terminal receives the SIB 1. For example, N is 1. In other words, if the terminal transmits the PRACH at the Nth RO after the terminal receives the SIB 1, the terminal can determine the first transmission power of the second PRACH based on the first information using the method provided in the embodiments of the present application. Otherwise, the terminal determines the transmission power of the second PRACH according to the existing scheme.

[0169] In another possible implementation, an interval between the time window for the terminal to receive the SIB 1 and the time for the terminal to send the second PRACH is less than or equal to the second time interval. In other words, in the case that the interval between the time window for the terminal to receive the SIB 1 and the time for the terminal to send the PRACH is less than or equal to the second time interval, the terminal can use the method provided in the embodiments of the present application, i.e., determining the first transmission power of the second PRACH based on the first information.

[0170] In the embodiments of the present application, the access network device can broadcast the SIB 1 within the time window for the terminal to receive the SIB 1, and stop broadcasting the SIB 1 outside the time window.

[0171] In one example, an interval between the end time of the time window for the terminal to receive the SIB 1 and the time for the terminal to send the second PRACH is less than or equal to the second time interval. For example, the second time interval is 2 slots, the time window is slot 0 to slot 9, the end time of the time window is slot 9, the terminal sends the second PRACH at slot 10, the interval between slot 9 and slot 10 is 1 slot, which is less than the second time interval, therefore, the terminal can use the method provided in the embodiments of the present application.

[0172] In another example, an interval between the start time of the time window for the terminal to receive the SIB 1 and the time for the terminal to send the second PRACH is less than or equal to the second time interval. For example, the second time interval is 12 slots, the time window is slot 0 to slot 9, the start time of the time window is slot 0, the terminal sends the second PRACH at slot 10, the interval between slot 0 and slot 10 is 10 slots, which is less than the second time interval, therefore, the terminal can use the method provided in the embodiments of the present application.

[0173] In the embodiments of the present application, the time window, the start time of the time window, the end time of the time window, the time for the terminal to send the second PRACH, and the time interval can be a slot, or a subframe, or a radio frame level, or in other words, in units of slots or subframes or radio frames. The second time interval can be protocol predefined or configured by the base station. Or it can also be understood that the length of the second time interval can be protocol predefined or configured by the base station.

[0174] In another possible implementation, in the case that the transmission beam of the first PRACH is the same as the transmission beam of the second PRACH, the terminal can use the method provided in the embodiments of the present application to determine the first transmission power of the second PRACH.

[0175] It should be understood that the above applicable condition can be regarded as a constraint on the time period from the terminal receiving the SIB 1 to the terminal sending the second PRACH. If the interval between the time when the terminal sends the first PRACH and the time when the terminal sends the second PRACH is long, since the terminal can move, the channel condition can change, and if the first sending power of the second PRACH is determined again based on the first information, the first sending power obtained can not be applicable to the current channel environment, thereby causing the access success rate of the second PRACH to decrease. Therefore, the terminal can enable the method of the embodiments of the present application to determine the first sending power of the second PRACH in the case where the above applicable condition is met. Conversely, if the terminal determines that the above applicable condition is not met, the method of the embodiments of the present application is not enabled to determine the first sending power of the second PRACH, that is, the sending power of the second PRACH is determined by using the existing scheme described above, and the second PRACH is sent by using the sending power.

[0176] Optionally, before S703, the method 700 further includes S705: the access network device sends indication information, the indication information being used to indicate that the terminal is allowed to determine the first sending power of the second PRACH based on the first information. Correspondingly, the terminal receives the indication information.

[0177] The embodiments of the present application do not make any limitation on the execution sequence between S705 and S702 and S701.

[0178] Optionally, the access network device can carry the indication information in the SIB 1. The indication information can also be referred to as enabling information, enabling the terminal to use the method provided by the embodiments of the present application, that is, to determine the first sending power of the second PRACH based on the first information. Of course, the access network device can also indicate the terminal not to use the method provided by the embodiments of the present application to determine the sending power of the second PRACH. That is, the terminal determines the sending power of the second PRACH according to the existing scheme described above, and sends the second PRACH by using the sending power. The indication information can also be carried in other SIBs or in the configuration information of the UL WUS.

[0179] Exemplarily, the SIB 1 includes a first field, if the field takes the value “0”, it indicates that the present scheme is not enabled, or in other words, the existing scheme is enabled; if the field takes the value “1”, it indicates that the present scheme is enabled, that is, the terminal is instructed to use the method provided by the embodiments of the present application to determine the first sending power of the second PRACH.

[0180] It can be understood that the various numbers involved in the embodiments of the present application are only used for differentiation for convenience of description, and do not limit the scope of the embodiments of the present application. The size of the serial numbers of the above processes does not mean the execution sequence, and the execution sequence of the processes should be determined according to the functions and the inherent logic.

[0181] It should be noted that, in order to implement the functions in the above embodiments, the access network device and the terminal include 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.

[0182] The method for random access according to the embodiments of the present application is described in detail above in combination with FIG. 7. The communication apparatus according to the embodiments of the present application will be described in detail below in combination with FIG. 8 and FIG. 9.

[0183] FIG. 8 and FIG. 9 are schematic block diagrams of the communication apparatus provided by the embodiments of the present application. The communication apparatus can be used to implement the functions of the terminal or the access network device in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0184] As shown in FIG. 8, the communication apparatus 800 includes a processing module 820 and a transceiver module 810. The transceiver module 810 can also be referred to as a communication interface or a communication module.

[0185] The apparatus 800 can be used to perform the actions performed by the terminal or the access network device in the above method embodiments. Alternatively, the apparatus 800 is a component (for example, a chip) configured in the terminal or the access network device. The processing module 820 is configured to perform processing-related operations of the terminal or the access network device in the above method embodiments. The transceiver module 810 is configured to perform receiving and transmitting-related operations of the terminal or the access network device in the above method embodiments.

[0186] Optionally, the transceiver module 810 can include a transmitting module and a receiving module. The transmitting module is configured to perform the transmitting operations in the above method embodiments. The receiving module is configured to perform the receiving operations in the above method embodiments.

[0187] It should be noted that the apparatus 800 can include the transmitting module and not include the receiving module. Alternatively, the apparatus 800 can include the receiving module and not include the transmitting module. Specifically, whether the apparatus 800 includes the transmitting action and the receiving action in the above solutions can be determined.

[0188] Optionally, the apparatus 800 is configured to perform the actions performed by the terminal in the embodiments shown in FIG. 7. For details, please refer to the related description in the embodiments shown in FIG. 7, which will not be described here again.

[0189] Optionally, the apparatus 800 further includes a storage module, which can be configured to store data, and / or to store computer programs or instructions, the processing module 820 can read the computer programs / instructions and / or data in the storage module, so that the apparatus 800 implements the above-mentioned method embodiments.

[0190] When the apparatus 800 is configured to implement the functions of the terminal in the method embodiments as shown in FIG. 7, the transceiver module 810 is configured to: transmit a first PRACH, the first PRACH being used to request a SIB 1; and receive the SIB 1, the SIB 1 including configuration information of a second PRACH. The processing module 820 is configured to: determine a first transmission power of the second PRACH based on first information, the first information including a transmission power of the first PRACH, or the first information including a parameter related to the transmission power of the first PRACH. The transceiver module 810 is further configured to: transmit the second PRACH at the first transmission power.

[0191] Optionally, the first information includes the transmission power of the first PRACH. The processing module 820 is configured to: determine the transmission power of the first PRACH as the first transmission power of the second PRACH.

[0192] Optionally, the first information includes the transmission power of the first PRACH. The processing module 820 is configured to: determine a maximum value between the transmission power of the first PRACH and a second transmission power of the second PRACH as the first transmission power of the second PRACH, the second transmission power of the second PRACH being a transmission power determined based on the configuration information of the second PRACH.

[0193] Optionally, the first information includes the parameter related to the transmission power of the first PRACH. The processing module 820 is configured to: determine a target reception power of the second PRACH based on the parameter related to the transmission power of the first PRACH; and determine the first transmission power of the second PRACH based on the target reception power of the second PRACH.

[0194] Optionally, the parameter related to the transmission power of the first PRACH includes a target reception power of the first PRACH. The processing module 820 is configured to: determine the target reception power of the first PRACH as a target reception power of the second PRACH.

[0195] Optionally, the parameter related to the transmission power of the first PRACH includes a power ramping counter of the first PRACH. The processing module 820 is configured to: determine the target reception power of the second PRACH based on the power ramping counter of the first PRACH.

[0196] Optionally, an interval between a time at which the terminal receives the SIB 1 and a time at which the terminal transmits the second PRACH is less than or equal to a first time interval.

[0197] Optionally, an interval between a time window for the terminal to receive the SIB 1 and a time at which the terminal transmits the second PRACH is less than or equal to a second time interval.

[0198] Optionally, the transceiver 810 is configured to receive indication information, the indication information being used to indicate that the terminal is allowed to determine the first transmission power of the second PRACH based on the first information.

[0199] When the apparatus 800 is configured to implement the functions of the access network device in the method embodiment as shown in FIG. 7, the transceiver 810 is configured to: receive a first PRACH, the first PRACH being used to request a SIB 1; transmit the SIB 1, the SIB 1 including configuration information of a second PRACH; and receive the second PRACH.

[0200] Optionally, the transceiver 810 is configured to transmit indication information, the indication information being used to indicate that the terminal is allowed to determine the first transmission power of the second PRACH based on the first information.

[0201] For more detailed descriptions of the steps, reference can be made to the related descriptions in the method embodiments above, which will not be repeated here.

[0202] FIG. 9 is a schematic block diagram of another communication apparatus 900 provided by the embodiments of the present application. As shown in FIG. 9, the apparatus 900 includes one or more processors 910 and interface circuitry 920. The one or more processors 910 and the interface circuitry 920 are coupled to each other. It can be understood that the interface circuitry 920 can be a transceiver or an input / output interface. Optionally, the apparatus 900 can further include a memory 930, which is used to store instructions executed by the processor 910, or is used to store input data required by the processor 910 to execute instructions, or is used to store data generated after the processor 910 executes instructions. Sometimes, the interface circuitry 920 can also be understood as a part of the one or more processors 910, and in this case, the apparatus 900 includes the one or more processors 910.

[0203] The one or more processors 910 and the memory 930 can be separately arranged or integrally arranged, which is not limited in the present application.

[0204] When the apparatus 900 is configured to implement the method shown in FIG. 7, the one or more processors 910 are configured to implement the functions of the processing module 820, and the interface circuitry 920 is configured to implement the functions of the transceiver 810.

[0205] When the apparatus 900 is a chip applied to a terminal, the chip of the terminal implements the functions of the terminal in the method embodiments. The chip of the terminal receives information from an access network device, 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 chip of the terminal by the modules. The chip of the terminal transmits information to the access network device, 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 access network device by the modules.

[0206] When the apparatus 900 is a chip applied to an access network device, the chip of the access network device implements the functions of the access network device in the method embodiments. The chip of the access network device 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 access network device, and then transmitted to the chip of the access network device by the modules. The chip of the access network device 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 access network device, and then transmitted to the terminal by the modules.

[0207] The embodiments of the present application further provide a computer readable storage medium for storing a computer program, which can make a computer execute the method in the above embodiments when the computer program runs on the computer. In other words, the computer program includes instructions for implementing the method in the above embodiments.

[0208] The embodiments of the present application further provide a computer program product, which includes a computer program or instructions, which can make a computer execute the method in the above embodiments when the computer program or instructions runs on the computer.

[0209] The embodiments of the present application further provide a chip, which includes at least one processor for supporting implementation of the method in the above embodiments, such as receiving or processing data involved in the method in the above embodiments.

[0210] It should be understood that, in the embodiments of the present application, the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0211] In the implementation process, each step of the above method can be completed by the integrated logic circuit of hardware in the processor or the instruction in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as the execution of hardware processor, or the execution of hardware and software module combination in the processor. The software module can be located in the storage medium mature in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, or the like. The storage medium is located in the memory, and the processor executes the instruction in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0212] Those of ordinary skill in the art can realize that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0213] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system, device and module can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0214] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. For example, the division of the modules is merely a logical function division. There can be another division manner for the actual implementation, for example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different modules can be indirect couplings or communication connections through some interfaces, devices or modules, and can be in electrical, mechanical or other forms.

[0215] The modules illustrated as separated components can or can not be physically separated, and the components illustrated as modules can or can not be physical modules, i.e., can be located in one place, or can be distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0216] In addition, the functional modules in each embodiment of the present application can be integrated into a processing module, or each module can be physically present alone, or two or more modules can be integrated into one module.

[0217] If the functions are realized in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program codes that can be stored in the medium.

[0218] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for random access, characterized by, The method comprises: sending a first physical random access channel (PRACH), the first PRACH being used for requesting a system information block (SIB) 1; receiving the SIB 1, the SIB 1 comprising configuration information of a second PRACH; determining a first transmission power of the second PRACH based on first information, the first information comprising a transmission power of the first PRACH, or the first information comprising a parameter related to the transmission power of the first PRACH; sending the second PRACH with the first transmission power.

2. The method of claim 1, wherein, The first information comprises the transmission power of the first PRACH. The determining the first transmission power of the second PRACH based on the first information comprises: determining the transmission power of the first PRACH as the first transmission power of the second PRACH.

3. The method of claim 1, wherein, The first information comprises the transmission power of the first PRACH. The determining the first transmission power of the second PRACH based on the first information comprises: determining a maximum value between the transmission power of the first PRACH and a second transmission power of the second PRACH as the first transmission power of the second PRACH, the second transmission power of the second PRACH being a transmission power determined based on the configuration information of the second PRACH.

4. The method of claim 1, wherein, The first information comprises a parameter related to the transmission power of the first PRACH. The determining the first transmission power of the second PRACH based on the first information comprises: determining a target reception power of the second PRACH based on the parameter related to the transmission power of the first PRACH; determining the first transmission power of the second PRACH based on the target reception power of the second PRACH.

5. The method of claim 4, wherein, The parameter related to the transmission power of the first PRACH comprises a target reception power of the first PRACH. The determining the target reception power of the second PRACH based on the parameter related to the transmission power of the first PRACH comprises: determining the target reception power of the first PRACH as the target reception power of the second PRACH.

6. The method of claim 4, wherein, The parameter related to the transmission power of the first PRACH comprises a power ramping counter of the first PRACH. The determining the target reception power of the second PRACH based on the parameter related to the transmission power of the first PRACH comprises: determining the target reception power of the second PRACH based on the power ramping counter of the first PRACH.

7. The method according to any one of claims 1 to 6, characterized in that, An interval between a time at which the terminal receives the SIB 1 and a time at which the terminal sends the second PRACH is less than or equal to a first time interval.

8. The method according to any one of claims 1 to 6, characterized in that, A time window for the terminal to receive the SIB 1 and a time at which the terminal sends the second PRACH is less than or equal to a second time interval.

9. The method according to any one of claims 1 to 8, characterized in that, Before the determining the first transmission power of the second PRACH based on the first information, the method further comprises: receiving indication information, the indication information being used for indicating that a terminal is allowed to determine the first transmission power of the second PRACH based on the first information.

10. A communications device, characterized by comprising means for implementing the method of any one of claims 1 to 9.

11. A communications device, characterized by comprising at least one processor coupled with a memory for storing a program or instructions that, when executed by the at least one processor, cause the method of any one of claims 1 to 9 to be performed.

12. A computer-readable storage medium, characterized in that, a computer program for storing, which, when run on a computer, causes the method of any one of claims 1 to 9 to be performed.

13. A computer program product, characterised in that, comprising: a computer program or instructions that, when run, cause the method of any one of claims 1 to 9 to be performed.

Images