WO2023066335A1

WO2023066335A1 - Random access method and apparatus

Info

Publication number: WO2023066335A1
Application number: PCT/CN2022/126406
Authority: WO
Inventors: 王珏; 娄崇; 顾志方
Original assignee: 华为技术有限公司
Priority date: 2021-10-21
Filing date: 2022-10-20
Publication date: 2023-04-27
Also published as: CN116017753A

Abstract

Embodiments of the present application provide a random access method and apparatus. A terminal device determining whether there is a synchronization signal and physical broadcast channel block (SSB) having a synchronization reference signal receiving power (SS-RSRP) higher than a first threshold; the terminal device determining whether a condition that a request message 3 is repeated is satisfied; if the condition that the request message 3 is repeated is met, and if there is an SSB having an SS-RSRP higher than the first threshold, executing contention-free random access; or, executing contention-based random access, and executing message 3 repetition during execution of the contention-based random access. By means of the present method, conflict occurring when a terminal device executes SSB selection and message 3 repetition determination can be resolved, while also taking time delay and resource efficiency of random access into account.

Description

Method and device for random access

This application claims the priority of the Chinese patent application with the application number 202111225347.2 and the title of the invention "method and device for random access" submitted to the State Intellectual Property Office of China on October 21, 2021, the entire contents of which are incorporated herein by reference Applying.

technical field

The embodiments of the present application relate to the field of wireless communication, and in particular, to a random access method and device.

Background technique

With the development of communication technology and the improvement of user needs, the terminal equipment in the communication scene gradually presents the characteristics of large quantity and multiple forms. For example, in the industrial automation scenario, there are a large number of monitoring equipment, machines, or sensors in the factory; in the family and life scenarios, there are a large number of mobile phones, tablets, wearable devices, smart home appliances, or vehicle-mounted terminal devices. The random access process is an important process for establishing a wireless link between the terminal device and the network. Therefore, reducing the time delay of the random access process and improving the efficiency of the random access process has become an urgent problem to be solved.

Contents of the invention

The present application provides a random access method and device, which are used to reduce the time delay of the random access process and improve the efficiency of the random access process.

In a first aspect, the present application provides a method for random access, where the subject of execution of the method is a terminal device. The terminal device judges whether there is a synchronization signal and a physical broadcast channel block SSB with a synchronization reference signal received power SS-RSRP higher than a first threshold, wherein the first threshold is preset by the access network device; the terminal device judges whether the request is satisfied The condition for message 3 repetition; if the condition for requesting message 3 repetition is satisfied, and there is an SSB with the SS-RSRP higher than the first threshold, the terminal device performs non-contention random access; or, if the request is satisfied The condition of message 3 repetition, and there is an SSB with the SS-RSRP higher than the first threshold, the terminal device performs contention-based random access, and performs message 3 repetition during the process of performing the contention-based random access .

By implementing the method described in the first aspect, the contradiction that occurs when the terminal device performs SSB selection and message 3 repetition judgment can be resolved. When the network load is high and the delay requirement is high, you can choose to implement CFRA when the above contradictions occur, and reduce the time for terminal equipment to access the access network equipment by avoiding preamble collisions and simplifying the steps of the random access process. Delay; when the network load is low, the delay requirement is low, and the random access resources are sufficient, CBRA can be selected when the above contradiction occurs. By implementing the above method, both the time delay and resource efficiency of random access can be taken into consideration.

In a possible implementation manner of the first aspect, the satisfying the condition for requesting message 3 repetition specifically includes: the reference signal received power RSRP of the downlink reference signal is lower than a second threshold, where the second threshold is The aforementioned access network devices are preset.

In a possible implementation manner of the first aspect, the judging whether the condition for requesting message 3 repetition is met specifically includes: if there is no SSB whose SS-RSRP is higher than the first threshold, judging whether the Condition for request message 3 repetition. By implementing this method, if the terminal device judges to execute CFRA when executing SSB selection, it does not need to execute the judgment of message 3 repetition; if the terminal device judges to execute CBRA when executing SSB selection, it then executes the judgment of message 3 repetition. In this way, it is possible to avoid conflicts between the terminal device performing SSB selection and the judgment of message 3 repetition, and to improve the efficiency of random access.

In a possible implementation manner of the first aspect, the terminal device judges whether there is a random access resource supporting message 3 repetition on the active uplink partial bandwidth BWP.

In a possible implementation manner of the first aspect, the terminal device receives configuration information from the access network device; the terminal device determines the number of repetitions of message 3 corresponding to each SSB in the first SSB set according to the configuration information, Wherein, the first SSB set is part or all of all SSBs that can be detected by the terminal device.

In a possible implementation manner of the first aspect, the terminal device selects a first SSB from the first SSB set, and sends an The network access device sends a random access preamble corresponding to the first SSB.

In a possible implementation manner of the first aspect, the terminal device receives a first message from the access network device, where the first message indicates the adjusted number of repetitions of message 3 .

In a second aspect, the present application provides a method for random access, where the subject of execution of the method is a terminal device. The terminal device receives configuration information from the access network device; the terminal device determines the number of repetitions of message 3 corresponding to each SSB in the first SSB set according to the configuration information; the terminal device repeats according to the message 3 corresponding to each SSB in the first SSB set The number of times determines the first SSB and the number of repetitions of message 3 corresponding to the first SSB; the terminal device sends the preamble corresponding to the first SSB to the access network device on the RO resource corresponding to the first SSB.

In a possible implementation manner of the second aspect, the terminal device receives a first message from the access network device, where the first message indicates the adjusted number of repetitions of message 3 .

By implementing the method described in the second aspect, the terminal device can choose to report the requested number of repetitions of message 3, and the access network device can also indicate the adjusted number of repetitions of message 3 by sending information, so that the terminal device can use an appropriate number of repetitions Sending message 3 avoids waste of resources while improving the reliability of random access.

In a third aspect, a communication device is provided, including functional modules for implementing the method in the foregoing first aspect, any possible implementation manner of the first aspect, the second aspect, and any possible implementation manner of the second aspect.

In a fourth aspect, a communication device is provided, including a processor and an interface circuit, and the interface circuit is used to receive signals from other communication devices other than the communication device and transmit them to the processor or send signals from the processor For other communication devices other than the communication device, the processor is used to implement the aforementioned first aspect, any possible implementation of the first aspect, the second aspect, and any possible implementation of the second aspect through a logic circuit or by executing code instructions. method in the implementation.

In a fifth aspect, a communication device is provided, including a processor and a memory, the processor is coupled to the memory, and the processor is used to control the device to implement the aforementioned first aspect, any possible implementation of the first aspect, and the second aspect, a method in any possible implementation of the second aspect.

According to the sixth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores computer programs or instructions. When the computer programs or instructions are executed, any possibility of the aforementioned first aspect and the first aspect can be realized. The implementation manner of the second aspect, the method in any possible implementation manner of the second aspect.

In a seventh aspect, a computer program product containing instructions is provided. When the instructions are executed, the aforementioned first aspect, any possible implementation of the first aspect, the second aspect, and any possible implementation of the second aspect are realized methods in methods.

In an eighth aspect, a computer program is provided, the computer program includes codes or instructions, and when the codes or instructions are executed, the aforementioned first aspect, any possible implementation of the first aspect, the second aspect, the second A method in any possible implementation of an aspect.

In the ninth aspect, there is provided a chip system, the chip system includes a processor, and may also include a memory, so as to implement the aforementioned first aspect, any possible implementation of the first aspect, the second aspect, and any possible implementation of the second aspect methods in methods. The system-on-a-chip may consist of chips, or may include chips and other discrete devices.

Description of drawings

FIG. 1 is a schematic diagram of a contention-based four-step random access provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of a contention-based two-step random access provided by an embodiment of the present application;

FIG. 3 is a schematic diagram of a non-contention-based four-step random access provided by an embodiment of the present application;

FIG. 4 is a schematic diagram of a non-contention-based two-step random access provided by an embodiment of the present application;

FIG. 5, FIG. 6 and FIG. 7 are schematic flowcharts of the data transmission method provided by the embodiment of the present application;

FIG. 8 and FIG. 9 are schematic structural diagrams of a possible communication device provided by an embodiment of the present application.

Detailed ways

The technical solutions provided by the embodiments of the present application can be applied to various communication systems, such as: long term evolution (long term evolution, LTE) system, fifth generation (5th generation, 5G) mobile communication system, WiFi system, future communication system, Or a system in which multiple communication systems are integrated, etc., are not limited in this embodiment of the present application. Among them, 5G can also be called new radio (new radio, NR).

The technical solution provided by the embodiment of the present application can be applied to various communication scenarios, for example, it can be applied to one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (ultra -reliable low-latency communication (URLLC), machine type communication (machine type communication, MTC), large-scale machine type communication (massive machine type communications, mMTC), device-to-device (device-to-device, D2D), outside the vehicle Networking (vehicle to everything, V2X), vehicle to vehicle (vehicle to vehicle, V2V), and Internet of things (Internet of things, IoT), etc.

In the embodiment of this application, "/" can indicate that the objects associated before and after are in an "or" relationship, for example, A/B can indicate A or B; "and/or" can be used to describe that there are three types of associated objects A relationship, for example, A and/or B, may mean: A exists alone, A and B exist simultaneously, and B exists alone. Among them, A and B can be singular or plural. In this embodiment of the application, words such as "first" and "second" may be used to distinguish technical features with the same or similar functions. The words "first" and "second" do not limit the number and execution order, and the words "first" and "second" do not necessarily mean that they must be different. In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or illustrations, and embodiments or designs described as "exemplary" or "for example" should not be interpreted as More preferred or more advantageous than other embodiments or design solutions. The use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner for easy understanding.

The terminal device involved in this embodiment of the present application may also be referred to as a terminal, and may be a device with a wireless transceiver function). The terminal device may be a user equipment (user equipment, UE), and the UE includes a handheld device with a wireless communication function, a vehicle device, a wearable device, or a computing device. Exemplarily, the UE may be a mobile phone, a tablet computer, or a computer with a wireless transceiver function. Terminal devices can also be virtual reality terminal devices, augmented reality terminal devices, wireless terminals in industrial control, wireless terminals in unmanned driving, wireless terminals in telemedicine, wireless terminals in smart grids, and wireless terminals in smart cities , and/or wireless terminals in a smart home, etc.

In this embodiment of the application, the device used to realize the function of the terminal device may be a terminal device; it may also be a device capable of supporting the terminal device to realize the function, such as a chip system, which may be installed in the terminal device or connected with the terminal device Matching is used. In the embodiment of the present application, the system-on-a-chip may be composed of chips, or may include chips and other discrete devices. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application will be described by taking the terminal device as an example for realizing the functions of the terminal device.

The access network device involved in the embodiment of the present application includes a base station (base station, BS), which may be a device deployed in a wireless access network and capable of wireless communication with a terminal device. Base stations may come in various forms, such as macro base stations, micro base stations, relay stations, and access points. The base station involved in the embodiment of the present application may be a base station in the 5G system or a base station in the LTE system, where the base station in the 5G system may also be called a transmission reception point (transmission reception point, TRP) or a next-generation node B (generation Node B, gNB or gNodeB). In the embodiment of the present application, the device for implementing the function of the access network device may be the access network device; it may also be a device capable of supporting the access network device to realize the function, such as a chip system, and the device may be installed on the access network It can be used in network access equipment or matched with access network equipment. In the technical solution provided by the embodiment of the present application, the technical solution provided by the embodiment of the present application is described by taking the access network device as an example for realizing the function of the access network device.

The relevant technical features involved in the embodiments of the present application are explained below. It should be noted that these explanations are for the purpose of making the embodiments of the present application easier to understand, and should not be regarded as limiting the scope of protection required by the present application.

1. Random access

Random access includes contention based random access (CBRA) and contention free random access (CFRA).

(a) CBRA

Step 1: The terminal device sends a preamble (also called Msg1) to the access network device, and the access network device obtains the preamble ID (RAPID) by detecting the preamble, and estimates the transmission delay.

Step 2: The access network device replies RAR (also called Msg2) to the terminal device, which carries the timing advance (timing advance, TA) corresponding to the transmission delay estimated in step 1, which is the message 3 in step 3 (also called The time-frequency domain resource and the temporary cell radio network temporary identity (TC-RNTI) etc. which may be referred to as the transmission configuration of Msg3).

Step 3, step 4: If multiple terminal devices use the same time-frequency domain resources to send the same preamble in step 1, conflicts and competition will occur, and steps 3 and 4 are used for contention resolution. Specifically, after receiving the RAR corresponding to its own RAPID, the terminal device adjusts the uplink timing according to the TA in it, and sends message 3 on the time-frequency domain resources allocated by the RAR, and the message 3 will carry the identity of the terminal device. Next, the access network device replies a contention resolution message (message 4, also referred to as Msg4) to the terminal device, and if the terminal device receives message 4 corresponding to its own identity, it successfully completes the random access process.

(b) CFRA

If the terminal device meets the CFRA conditions, it will use dedicated random access resources and preamble. At this time, there is no contention conflict, so it is not necessary to perform steps 3 and 4 in CBRA.

Wherein, whether the terminal device performs CBRA or CFRA depends on triggering a random access event and random access resources configured by the access network device for the terminal device. Events that trigger a CBRA can include:

(1) The terminal device initially accesses the cell, from the radio resource control (radio resource control, RRC) idle state to the RRC connection state

(2) RRC connection reestablishment

(3) The terminal device is in the RRC connection state, and uplink data arrives, but the uplink is not synchronized or there is no available physical uplink shared channel (PUSCH) resource transmission scheduling request (scheduling request, SR)

(4) SR sending failed

(5) The terminal device changes from the RRC inactive state to the RRC connection state

Events that trigger CFRA can include:

(1) The terminal device is in the RRC connection state, and the downlink data arrives, but the uplink is not synchronized

(2) Synchronous reconfiguration triggered by RRC, such as handover

(3) After adding the secondary cell (SCell), the uplink synchronization between the terminal device and the SCell is established

(4) System message request

(5) Special cell (Spcell) beam failure recovery. Among them, when there is dual connection, SpCell refers to the primary cell (PCell) in the primary cell group (master cell group, MCG) and the primary secondary cell (PSCell) in the secondary cell group (secondary cell group, SCG); when there is no In dual connectivity, the SpCell is the primary cell.

Among the events that trigger CFRA, except event (3), if the CFRA conditions are not met in other cases, for example, the access network device is not configured with CFRA resources, CBRA will be executed.

2. Four-step random access and two-step random access

Random access may include four-step random access and two-step random access.

In four-step random access, the terminal device sends a preamble (preamble) to the access network device through a physical random access channel (PRACH), that is, sends a message 1 to the access network device; the access network device After receiving the access preamble, a random access response (random access response, RAR) is sent to the terminal device, that is, the access network device sends a message 2 to the terminal device, and the RAR can indicate the resource location of the PUSCH; PUSCH resource location, send message 3 to the access network device through PUSCH; after receiving message 3, the access network device can send message 4 to the terminal device. Optionally, message 3 may include an RRC setup request (RRCSetupResuest) message or an RRC resume request (RRCResumeResuest) message. Optionally, message 4 may include one or more of the following information: RRC setup (RRCSetup) message, RRC recovery (RRCResume) message, PUSCH acknowledgment (acknowledgment)/negative acknowledgment (negative acknowledgment) in message 3, NACK), and power control commands, etc. In the embodiment of the present application, "four-step random access" may also be called: "4-step RACH" or "four-step RACH", and the embodiment of the present application does not limit the name.

In two-step random access, the terminal device sends an access preamble to the access network device through the PRACH, and sends uplink data to the access network device through the PUSCH, that is, the terminal device sends a message A to the access network device; After receiving message A, the access network device sends message B to the terminal device. Optionally, the message A may include an RRC setup request (RRCSetupResuest) message or an RRC resume request (RRCResumeResuest) message. Optionally, message B may include one or more of the following information: RRC Setup (RRCSetup) message, RRC Resume (RRCResume) message, ACK/NACK of PUSCH in message A, and power control command. In the embodiment of the present application, "two-step random access" may also be called "2-step RACH" or "two-step RACH", and the embodiment of the present application does not limit the name.

It should be noted that in the four-step random access process, the terminal device only sends the preamble in Msg1, while in the two-step random access process, the terminal device also sends uplink data in MsgA in addition to the preamble.

As shown in Figures 1 to 4, the 3rd Generation Partnership Project (3rd Generation Partnership Project, 3GPP) divides the random access process into the following four types: contention-based four-step random access (hereinafter referred to as 4-step CBRA ), non-contention-based four-step random access (hereinafter referred to as 4-step CFRA), contention-based two-step random access (hereinafter referred to as 2-step CBRA) and non-contention-based two-step random access (hereinafter referred to as called 2-step CFRA).

3. Random access initialization and resource selection

Before sending the preamble, the terminal device needs to perform random access initialization first, and select a carrier (NUL or SUL) for performing random access. Exemplarily, if the access network device configures NUL and SUL for the terminal device at the same time, the terminal device compares the reference signal received power (reference signal received power, RSRP) of the downlink reference signal with the threshold value rsrp configured by the access network device -ThresholdSSB-SUL, if RSRP is higher than rsrp-ThresholdSSB-SUL, the terminal device performs random access on NUL, otherwise performs random access on SUL.

The terminal device needs to select a part of the bandwidth (Bandwidthpart, BWP). Exemplarily, the terminal device checks whether random access resources are available on the currently active uplink BWP, and if not, switches to the BWP indicated by the parameter initialUplinkBWP.

After selecting the carrier and BWP, the terminal device needs to determine the type of random access (4-step random access or 2-step random access). Exemplarily, if 2-step random access resources and 4-step random access resources are configured on the selected BWP at the same time, and the RSRP of the downlink reference signal is higher than the threshold MsgA-RSRP-Threshold, the terminal device selects 2-step Random access, otherwise select 4-step random access.

Then the terminal device needs to select the downlink transmission beam, and inform the access network device of the selection result through the corresponding PRACH transmission resource (PRACH occasion, RO) and the preamble carried on the RO, so as to realize downlink beam alignment.

Exemplarily, for the scenario of triggering CFRA, the access network device configures one or more synchronization signals and physical broadcast channel block (synchronization signal and physical broadcast channel block, SSB) for the terminal device to determine whether to execute CFRA, if the terminal device If it is determined that one or more SSBs of this configuration have an SSB whose synchronization signal reference signal received power (SS-RSRP) is higher than the threshold rsrp-ThresholdSSB, then the terminal device will start from the SS-RSRP higher than the threshold rsrp-ThresholdSSB Select one of the SSBs to perform CFRA.

Four, message 3 (Msg 3) repeat

Message 3 repetition is a coverage enhancement technology, which improves the reliability of uplink transmission of users (especially cell edge users) by repeatedly sending message 3 in the random access process, and achieves the purpose of expanding uplink coverage.

Exemplarily, the terminal device determines whether to request repetition of message 3 from the access network device, and the access network device indicates the number of repetitions of message 3 to the terminal device requesting repetition of message 3 .

The terminal device obtains the threshold configured by the access network device from the system message for judging whether to request message 3 repetition, which is recorded as rsrp-ThresholdMsg3Rep in this embodiment of the application, and the name of the parameter is not limited in this embodiment of the application. In the process of random access initialization and resource selection, the terminal device compares the RSRP of the downlink reference signal with rsrp-ThresholdMsg3Rep, if the RSRP of the downlink reference signal is lower than rsrp-ThresholdMsg3Rep, it requests the access network device to perform message 3 repetition, and vice versa is not requested.

Terminal devices can group ROs and/or preambles according to parameters configured by access network devices, and terminal devices that request or do not request message 3 repetition will select different groups of ROs and/or preambles for message 1 transmission.

The access network device determines whether the terminal device requests message 3 to be repeated according to the preamble sent by the terminal device and/or the RO transmitting the preamble. For a terminal device that requests repetition of message 3, the access network device informs the terminal device of the number of repetitions through the RAR.

In the above events that trigger CFRA, for CFRA triggered by events (2) and (5), if the access network device configures 4-step CFRA resources for the terminal device, and there is at least one SS-RSRP in the configured SSB If it is higher than the threshold rsrp-ThresholdSSB, the terminal device will perform CFRA. If the terminal device performs the selection of message 3 repetition before SSB selection and judges that it needs to request message 3 repetition, but finds that there is an SSB whose SS-RSRP is higher than the threshold rsrp-ThresholdSSB during SSB selection, CFRA can be performed. However, since message 3 does not need to be transmitted in CFRA, the conclusion of whether to request message 3 repetition and the conclusion of SSB selection are contradictory. In addition, when the terminal device requests message 3 to be repeated, the access network device will determine the number of repetitions of message 3 according to the channel quality estimated from message 1 sent by the terminal device and indicate it to the terminal device. Once the multi-user interference noise is large, or the preamble collision occurs, the channel estimation error will be large. At this time, the access network device may indicate an inappropriate number of repetitions to the terminal device. If the number of repetitions is too large, it will cause Random access resources are wasted, and if the number of repetitions is too small, transmission failure will easily occur.

In view of this, the present invention provides a random access method, which is used to reduce the time delay of the random access process and improve the efficiency and reliability of the random access process.

FIG. 5 is a schematic flowchart of a random access method provided by an embodiment of the present application. This embodiment relates to a specific process of random access performed by an access network device and a terminal device. The executors of this embodiment may be the access network device and the terminal device, or may be modules respectively applied to the access network device and the terminal device, for example, a chip. In the following, an access network device and a terminal device are taken as execution bodies as examples for description.

As shown in Fig. 5, the method may include: S501, S502 and S503, wherein S503 may be replaced by S503a. The embodiment of the present application does not limit the execution sequence of each step, for example, S502 may be executed before S501.

S501. The terminal device judges whether a condition for requesting message 3 repetition is satisfied. Exemplarily, if the RSRP of the downlink reference signal is lower than the second threshold preset by the access network device, the condition of requesting message 3 repetition is satisfied; otherwise, if the RSRP of the downlink reference signal is higher than or equal to the preset threshold of the access network device The second threshold is not satisfied.

S502. The terminal device determines whether there is an SSB whose SS-RSRP is higher than the first threshold. Optionally, the first threshold is preset by the access network device. In a possible manner, the terminal device may determine whether there is an SSB whose SS-RSRP is higher than the first threshold among one or more SSBs configured by the access network device for the terminal device. In another possible manner, the terminal device may also determine whether there is an SSB whose SS-RSRP is higher than the first threshold among all SSBs that can be detected by the terminal device.

S503. If the condition of requesting message 3 repetition is satisfied, and there is an SSB whose SS-RSRP is higher than the first threshold, the terminal device executes CFRA. For example, if the condition of requesting message 3 repetition is met, and there is an SSB whose SS-RSRP is higher than the first threshold among one or more SSBs configured by the access network device for the terminal device, the terminal device executes CFRA.

Exemplarily, the terminal device selects an SSB from the SSBs whose SS-RSRP is higher than the first threshold, then selects the RO and preamble corresponding to the selected SSB from the random access resources configured by the access network device, and performs CFRA. Optionally, the random access resources configured by the access network device may be 4-step CFRA resources. Exemplarily, the access network device configures 4-step CFRA resources for the terminal device on the BWP selected by the terminal device.

Optionally, if the condition for requesting message 3 repetition is not met, and there is no SSB with SS-RSRP higher than the first threshold, the terminal device performs CBRA, and the terminal device does not perform message 3 repetition.

Exemplarily, the terminal device selects an SSB among all SSBs that the terminal device can detect, and selects a random access resource corresponding to the selected SSB from the group of random access resources corresponding to the repetition of the message 3 ( RO and/or preamble), and use the random access resources to perform CBRA.

Optionally, if the condition for requesting repetition of message 3 is met, and there is no SSB whose SS-RSRP is higher than the first threshold, the terminal device executes CBRA, and the terminal device executes repetition of message 3 .

Exemplarily, the terminal device selects one SSB among all SSBs that can be detected by the terminal device, and selects a random access resource (RO and/or preamble), and use the random access resources to perform CBRA.

Optionally, if the condition for requesting message 3 repetition is not met, and there is an SSB with SS-RSRP higher than the first threshold, the terminal device executes CFRA.

Exemplarily, the terminal device selects an SSB from the SSBs whose SS-RSRP is higher than the first threshold, then selects the RO and preamble corresponding to the selected SSB from the 4-step CFRA resources configured by the access network device, and executes CFRA .

Optionally, S503 may be replaced by S503a.

S503a. If the condition for requesting message 3 repetition is met, and there is an SSB with SS-RSRP higher than the first threshold, the terminal device executes CBRA, and in the process of executing CBRA, executes message 3 repetition.

Exemplarily, the terminal device selects an SSB among the SSBs whose SS-RSRP is higher than the first threshold, and selects a random access resource corresponding to the selected SSB in the group of random access resources corresponding to the request message 3 repetition ( RO and/or preamble), and use the random access resources to perform CBRA.

It can be understood that in S503a, if the condition of repeating message 3 is met, CBRA will be executed, and during the process of executing CBRA, repeating message 3 will be executed. That is, if the terminal device judges that the condition for repeating message 3 is met, S502 may not be executed.

The foregoing embodiments provide a method for random access, which can resolve the contradiction that occurs when the terminal device performs SSB selection and message 3 repetition judgment. When the network load is high and the delay requirement is high, you can choose to implement CFRA when the above contradictions occur, and reduce the time for terminal equipment to access the access network equipment by avoiding preamble collisions and simplifying the steps of the random access process. Delay; when the network load is low, the delay requirement is low, and the random access resources are sufficient, CBRA can be selected when the above contradiction occurs. By implementing the above method, the random access time delay and resource utilization can be taken into consideration.

FIG. 6 is a schematic flowchart of a random access method provided by an embodiment of the present application. This embodiment relates to a specific process of random access performed by an access network device and a terminal device. The executors of this embodiment may be the access network device and the terminal device, or may be modules respectively applied to the access network device and the terminal device, for example, a chip. In the following, an access network device and a terminal device are taken as execution bodies as examples for description.

As shown in FIG. 6, the method may include: S601, S602, S603 and S604. The embodiment of the present application does not limit the execution sequence of each step.

S601. The terminal device determines whether there is an SSB whose SS-RSRP is higher than a first threshold. Optionally, the first threshold is preset by the access network device. Optionally, the terminal device may determine whether there is an SSB whose SS-RSRP is higher than the first threshold among one or more SSBs configured by the access network device for the terminal device. Optionally, the terminal device may also determine whether there is an SSB whose SS-RSRP is higher than the first threshold among all SSBs that can be detected by the terminal device.

S602. If there is an SSB whose SS-RSRP is higher than the first threshold, execute S604; if there is no SSB whose SS-RSRP is higher than the first threshold, judge whether the condition for requesting message 3 repetition is met. Wherein, judging whether the condition for requesting message 3 repetition is satisfied specifically includes: if the RSRP of the downlink reference signal is lower than the second threshold preset by the access network device, the condition for requesting message 3 repetition is satisfied; otherwise, it is not satisfied.

S603. If the condition for requesting message 3 repetition is met, the terminal device executes CBRA, and in the process of executing CBRA, executes message 3 repetition.

If the condition for requesting message 3 repetition is not satisfied, the terminal device executes CBRA, and does not execute message 3 repetition during the process of executing CBRA.

S604. The terminal device executes CFRA. Exemplarily, the terminal device selects an SSB from the SSBs whose SS-RSRP is higher than the first threshold, and then selects the RO and preamble corresponding to the SSB from the 4-step CFRA resources configured by the access network device to perform random access.

The foregoing embodiments provide a method for random access. The terminal device first performs SSB selection, and then performs the judgment of message 3 repetition. When performing SSB selection, if the terminal device judges to execute CFRA, it does not need to perform the judgment of message 3 repetition; when performing SSB selection, if the terminal device judges to execute CBRA, it then executes the judgment of message 3 repetition. In this way, it is possible to avoid conflicts between the terminal device performing SSB selection and the judgment of message 3 repetition, and to improve the efficiency of random access.

Optionally, in the embodiments shown in FIG. 5 and FIG. 6, the terminal device's judgment of whether there is an SSB whose SS-RSRP is higher than the first threshold may be replaced by: the terminal device's judgment of whether there is a channel state information reference signal received power (channel A channel state information reference signal (channel state information reference signal, CSI-RS) whose state information reference signal received power (CSI-RSRP) is higher than the third threshold. Optionally, the third threshold is preset by the access network device. Exemplarily, the terminal device may determine whether there is a CSI-RS whose CSI-RSRP is higher than the third threshold among one or more CSI-RSs configured by the access network device for the terminal device.

Those skilled in the art should understand that in the embodiments shown in FIG. 5 and FIG. 6, "there is an SSB whose SS-RSRP is higher than the first threshold" can be replaced with "there is a CSI-RS whose CSI-RSRP is higher than the third threshold." ", "there is no SSB with SS-RSRP higher than the first threshold" may be replaced with "there is no CSI-RS with CSI-RSRP higher than the third threshold". That is, the judgment that the terminal device performs the comparison between the SS-RSRP of the SSB and the first threshold can be replaced by the judgment that the terminal device performs the comparison between the CSI-RSRP of the CSI-RS and the third threshold, and the functions of the two are the same.

Optionally, before performing the random access procedure, the terminal device may determine whether there is a random access resource supporting coverage enhancement on the active uplink BWP.

If there are only random access resources supporting coverage enhancement on the active uplink BWP, perform the first random access process; if there is no random access resource supporting coverage enhancement on the active uplink BWP, perform the second random access process ; If the active uplink BWP has random access resources that support coverage enhancement and non-coverage enhanced random access resources at the same time, execute any one or more of the embodiments S501 to S503a shown in Figure 5, or execute the Any one or more items in the embodiments S601 to S605 are illustrated.

Optionally, the first random access procedure is CBRA including message 3 repetition, and the second random access procedure is CBRA not including message 3 repetition.

Exemplarily, if the active uplink BWP of the terminal device has only random access resources supporting coverage enhancement, when CBRA is triggered, CBRA including message 3 repetition is performed.

Optionally, the random access resources supporting coverage enhancement represent random access resources used to execute the first random access procedure. That is, the random access resources supporting coverage enhancement can also be understood as the random access resources supporting message 3 repetition.

Optionally, if no random access resource is configured on the active uplink BWP of the terminal device, or there is no random access resource supporting coverage enhancement on the active uplink BWP and the number of preamble transmissions exceeds the threshold, the active uplink BWP is switched It is the BWP indicated by the parameter initialUplinkBWP, and executes any one of the embodiments S501 to S503a shown in FIG. 5 , or executes any one of the embodiments S601 to S605 shown in FIG. 6 .

FIG. 7 is a schematic flowchart of a random access method provided by an embodiment of the present application. This embodiment relates to a specific process of random access performed by an access network device and a terminal device. The executors of this embodiment may be the access network device and the terminal device, or may be modules respectively applied to the access network device and the terminal device, for example, a chip. In the following, an access network device and a terminal device are taken as execution bodies as examples for description.

As shown in FIG. 7, the method may include: S701, S702, S703, S704, and S705, wherein S705 is optional. The embodiment of the present application does not limit the execution sequence of each step.

S701. The terminal device receives configuration information from the access network device. Correspondingly, the access network device sends configuration item information to the terminal device.

S702. The terminal device determines the number of repetitions of message 3 corresponding to each SSB in the first SSB set according to the configuration information. Wherein, the first SSB set is part or all of all SSBs that can be detected by the terminal device.

Exemplarily, the access network device divides the SS-RSRP value range of the SSB into N interval segments, where N is a positive integer. Each interval segment corresponds to a value of the repetition times of message 3. Exemplarily, a form of the configuration information is shown in Table 1.

Table 1 The relationship between the value range of SS-RSRP and the number of repetitions of message 3

SS-RSRP取值范围SS-RSRP value range	消息3重复次数message 3 repetitions
a～ba~b	PP
c～dc~d	QQ
e～fe～f	RR

S703. The terminal device determines the first SSB and the message 3 repetition times corresponding to the first SSB according to the message 3 repetition times corresponding to each SSB in the first SSB set.

Exemplarily, the terminal device selects an SSB from the SSBs corresponding to the least number of repetitions of message 3, and determines the number of repetitions corresponding to the SSB. Exemplarily, the terminal device selects an SSB from the SSBs whose corresponding message 3 repetition times is less than or equal to a certain threshold, and determines the corresponding repetition times of the SSB, where the threshold may be preset by the access network device. Exemplarily, the terminal device selects one of the M SSBs with the highest SS-RSRP, where M is a positive integer, and determines the number of repetitions corresponding to the SSB. The embodiment of the present application does not limit the manner in which the terminal device determines the first SSB.

S704. The terminal device sends the preamble corresponding to the first SSB to the access network device on the RO resource corresponding to the first SSB. Correspondingly, the access network device receives the preamble from the terminal device, determines that the SSB used by the terminal device is the first SSB according to the preamble and the RO receiving the preamble, and determines the number of repetitions of message 3 corresponding to the first SSB.

Optionally, S705. The terminal device receives the first message from the access network device, and correspondingly, the access network device sends the first message to the terminal device. The first message indicates the adjusted number of repetitions of message 3 . Wherein, the first message may be carried on the UL grant field of the RAR.

Exemplarily, the first message includes two bits, as shown in Table 2.

An example of the first message in Table 2

第一消息的取值The value of the first message	第一消息的含义meaning of first message
0000	同意终端设备请求的消息3重复次数Number of repetitions of message 3 that agrees to the request of the terminal device
0101	终端设备请求的消息3重复次数减1The number of repetitions of message 3 requested by the terminal device minus 1
1010	终端设备请求的消息3重复次数加1Add 1 to the number of repetitions of message 3 requested by the terminal device
1111	不同意终端设备的消息3重复请求Disagree with message 3 repeat request from end device

It can be understood that Table 2 is only an example, and this embodiment of the present application does not limit the value and meaning of the first message. For example, the access network device divides the number of repetitions of message 3 into three levels through the configuration information, which are 2, 4, and 8. The first message may also indicate that the number of repetitions of message 3 requested by the terminal device is reduced by 1. Exemplarily, the number of repetitions of message 3 reported by the terminal device is 8, and the access network device indicates through the first message that the adjusted number of repetitions of message 3 is the gear of the number of repetitions of message 3 requested by the terminal device minus 1, that is, after adjustment The repetition count of message 3 is 4 times.

The above embodiments provide a method for random access. The terminal device can choose to report the number of repetitions of message 3 requested, and the access network device can also indicate the adjusted number of repetitions of message 3 by sending information, so that the terminal device can use an appropriate The number of repetitions to send message 3 avoids waste of resources while improving the reliability of random access.

With regard to the embodiments of the above-mentioned Figures 5 to 7, it should be noted that:

(1) The step numbers of the various flow charts described in the embodiment are only an example of the execution flow, and do not constitute a restriction on the sequence of execution of the steps. There is no strict order of execution. In addition, not all the steps illustrated in each flow chart are steps that must be executed, and some steps may be added or deleted on the basis of each flow chart according to actual needs.

(2) The above-mentioned embodiments of Fig. 5 to Fig. 7 can be implemented independently, and can also be combined with each other, for example, the embodiment shown in Fig. 5 and the embodiment shown in Fig. 7 are combined with each other, the embodiment shown in Fig. 6 and the embodiment shown in Fig. 7 The embodiments are combined with each other and the like.

(3) Some messages and parameters in the 5G communication system are used in the above embodiments, but in specific implementation, different messages or message names may be used, which is not limited in this embodiment of the present application.

FIG. 8 to FIG. 9 are schematic structural diagrams of possible communication devices provided by the embodiments of the present application. As shown in FIG. 8 , a communication device 800 includes a processing unit 810 and a transceiver unit 820 .

The communication apparatus 800 is used to implement the functions of the first access network device in the method embodiments shown in FIGS. 5 to 7 above, or, the communication apparatus 800 may include an Any function or operation module of the first access network device, the module may be fully or partially implemented by software, hardware, firmware or any combination thereof.

When the communication device 800 is used to realize the functions of the terminal equipment in the method embodiment shown in FIG. 5 , the processing unit 810 is used to judge whether the condition for requesting message 3 repetition is met; the processing unit 810 is also used to judge whether there is an SS-RSRP high SSB at the first threshold; if the condition of repeating the request message 3 is satisfied, and there is an SSB with SS-RSRP higher than the first threshold, the transceiver unit 820 is configured to perform CFRA; or, if the condition of repeating the request message 3 is met , and, there is an SSB whose SS-RSRP is higher than the first threshold, the transceiver unit 820 is configured to perform CBRA, and during the process of performing CBRA, perform message 3 repetition.

When the communication device 800 is used to realize the functions of the terminal equipment in the method embodiment shown in FIG. 6 , the processing unit 810 is used to judge whether there is an SSB whose SS-RSRP is higher than the first threshold; if there is an SS-RSRP higher than the first threshold For the SSB of the threshold, the processing unit 810 is also used to judge whether the condition for requesting message 3 repetition is met; if the condition for requesting message 3 repetition is met, the transceiver unit 820 is used for executing CBRA, and during the process of executing CBRA, execute message 3 repetition.

When the communication device 800 is used to implement the functions of the terminal device in the method embodiment shown in FIG. 7 , the transceiver unit 810 is used to receive configuration information from the access network device; the processing unit 810 is used to determine the first SSB according to the configuration information The number of repetitions of message 3 corresponding to each SSB in the set; the processing unit 810 is also used to determine the first SSB and the number of repetitions of message 3 corresponding to the first SSB according to the number of repetitions of message 3 corresponding to each SSB in the first SSB set; the transceiver unit The 820 is further configured to send the preamble corresponding to the first SSB to the access network device on the RO resource corresponding to the first SSB; the transceiver unit 820 is further configured to receive a first message from the access network device, the first message indicating the adjusted Number of repetitions for message 3.

More detailed descriptions about the processing unit 810 and the transceiver unit 820 can be directly obtained by referring to the related descriptions in the method embodiments shown in FIG. 5 , FIG. 6 or FIG. 7 , and will not be repeated here.

FIG. 9 is a schematic structural diagram of another possible communication device provided by an embodiment of the present application. As shown in FIG. 9 , a communication device 900 includes a processor 910 and an interface circuit 920 . The processor 910 and the interface circuit 920 are coupled to each other. It can be understood that the interface circuit 920 may be a transceiver or an input-output interface. Optionally, the communication device 900 may further include a memory 930 for storing instructions executed by the processor 910 or storing input data required by the processor 910 to execute the instructions or storing data generated after the processor 910 executes the instructions.

When the communication device 900 is used to implement the method shown in FIG. 5 , FIG. 6 , or FIG. 7 , the processor 910 is used to implement the functions of the processing unit 810 , and the interface circuit 920 is used to implement the functions of the transceiver unit 820 .

It can be understood that the processor in the embodiments of the present application can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application-specific integrated circuits (Application Specific Integrated Circuit, ASIC), Field Programmable Gate Array (Field Programmable Gate Array, FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. A general-purpose processor can be a microprocessor, or any conventional processor.

In the embodiment of the present application, the processor can be random access memory (Random Access Memory, RAM), flash memory, read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable In addition to programmable read-only memory (Erasable PROM, EPROM), electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium known in the art middle. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be a component of the processor. The processor and storage medium can be located in the ASIC. In addition, the ASIC can be located in a network device or a terminal device. Certainly, the processor and the storage medium may also exist in the network device or the terminal device as discrete components.

In the above embodiments, all or part of them may be implemented by software, hardware, firmware or any combination thereof. When implemented using software, it may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer programs or instructions. When the computer program or instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a terminal device, or other programmable devices. The computer program or instructions may be stored in or transmitted via a computer-readable storage medium. The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server integrating one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it may also be an optical medium, such as a DVD; it may also be a semiconductor medium, such as a solid state disk (solid state disk, SSD).

In each embodiment of the present application, if there is no special explanation and logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referred to each other, and the technical features in different embodiments are based on their inherent Logical relationships can be combined to form new embodiments.

It can be understood that the various numbers involved in the embodiments of the present application are only for convenience of description, and are not used to limit the scope of the embodiments of the present application. The size of the serial numbers of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic.

Claims

A random access method, characterized in that the method is applied to a terminal device or a chip in the terminal device, and the method includes:

Judging whether there is a synchronization signal and a physical broadcast channel block SSB with a synchronization reference signal received power SS-RSRP higher than a first threshold, where the first threshold is preset by the access network device;

Judging whether the condition for repeating the request message 3 is met;

If the condition for repeating the request message 3 is met, and there is an SSB whose SS-RSRP is higher than the first threshold, perform non-contention random access, or perform contention-based random access, and perform the Message 3 repetitions are performed during contention-based random access.
The method according to claim 1, wherein the condition for satisfying the repetition of the request message 3 specifically includes:

The RSRP of the downlink reference signal is lower than a second threshold, where the second threshold is preset by the access network device.
The method according to claim 1 or 2, wherein the judging whether the condition for requesting message 3 repetition is satisfied specifically includes:

If there is no SSB whose SS-RSRP is higher than the first threshold, it is judged whether the condition for repeating the request message 3 is satisfied.
The method according to any one of claims 1 to 3, wherein the method further comprises:

It is judged whether there is a random access resource supporting the repetition of message 3 on the active uplink partial bandwidth BWP.
The method according to any one of claims 1 to 4, wherein the method further comprises:

receiving configuration information from the access network device;

Determine the number of repetitions of message 3 corresponding to each SSB in the first SSB set according to the configuration information, where the first SSB set is part or all of all SSBs that can be detected by the terminal device.
The method according to claim 5, wherein the method further comprises:

Select a first SSB from the first SSB set, and send a random access preamble corresponding to the first SSB to the access network device on a physical random access channel (RO) resource corresponding to the first SSB .
The method according to claim 6, further comprising:

Receive a first message from the access network device, where the first message indicates the adjusted number of repetitions of message 3 .
The method according to claim 7, wherein the first message is carried in a random access response message.
A communication device, characterized in that the device includes:

A processing unit, configured to determine whether there is a synchronization signal and a physical broadcast channel block SSB whose synchronization reference signal received power SS-RSRP is higher than a first threshold, where the first threshold is preset by the access network device;

The processing unit also judges whether the condition for requesting message 3 repetition is satisfied;

The transceiver unit, if the condition for repeating the request message 3 is met, and there is an SSB with the SS-RSRP higher than the first threshold, the transceiver unit is configured to perform non-contention random access, or to perform contention-based random access Random access, and performing message 3 repetition during the process of performing the contention-based random access.
The device according to claim 9, wherein the condition for satisfying the repetition of the request message 3 specifically includes:

The RSRP of the downlink reference signal is lower than a second threshold, where the second threshold is preset by the access network device.
The device according to claim 9 or 10, wherein said judging whether the condition for repeating request message 3 is satisfied, specifically includes:

If there is no SSB whose SS-RSRP is higher than the first threshold, it is judged whether the condition for repeating the request message 3 is satisfied.
The device according to any one of claims 9 to 11, wherein the processing unit is further configured to:

It is judged whether there is a random access resource supporting the repetition of message 3 on the active uplink partial bandwidth BWP.
Apparatus according to any one of claims 9 to 12, characterized in that

The transceiver unit is further configured to receive configuration information from the access network device;

The processing unit is further configured to determine the number of repetitions of the message 3 corresponding to each SSB in the first SSB set according to the configuration information, wherein the first SSB set is part of all SSBs that can be detected by the terminal device Or all SSBs.
The device according to claim 13, characterized in that,

The processing unit is further configured to select a first SSB from the first SSB set, and the transceiver unit is further configured to send a message to the access network on the physical random access channel (RO) resource corresponding to the first SSB The device sends a random access preamble corresponding to the first SSB.
The device according to claim 14, wherein the transceiver unit is also used for:

Receive a first message from the access network device, where the first message indicates the adjusted number of repetitions of message 3 .
The device according to claim 15, wherein the first message is carried in a random access response message.
A communication device, characterized by comprising a module for performing the method according to any one of claims 1-8.
A communication device, characterized by comprising a processor and a memory, the processor is coupled to the memory, and the processor is used to control the device to implement the method according to any one of claims 1 to 8.
A communication device, characterized in that it includes a processor and an interface circuit, the interface circuit is used to receive signals from other communication devices other than the communication device and transmit them to the processor or transfer signals from the processor The signal is sent to other communication devices other than the communication device, and the processor implements the method according to any one of claims 1 to 8 through a logic circuit or executing code instructions.
A computer-readable storage medium, characterized in that computer programs or instructions are stored in the storage medium, and when the computer programs or instructions are executed by a communication device, the implementation of any one of claims 1 to 8 Methods.
A computer program product, characterized in that the computer program product includes instructions, and when the instructions are executed by a computer, the method according to any one of claims 1 to 8 is implemented.