CN116017753A

CN116017753A - Random access method and device

Info

Publication number: CN116017753A
Application number: CN202111225347.2A
Authority: CN
Inventors: 王珏; 娄崇; 顾志方
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2023-04-25
Also published as: WO2023066335A1

Abstract

The embodiment of the application provides a random access method and device. The terminal equipment judges whether synchronous signals and physical broadcast channel blocks SSB with synchronous reference signal received power SS-RSRP higher than a first threshold value exist or not; the terminal equipment judges whether the condition of repeating the request message 3 is satisfied; if the condition that the request message 3 is repeated is satisfied, and there is an SSB that the SS-RSRP is higher than a first threshold, performing non-contention random access; alternatively, contention based random access is performed, and message 3 repetition is performed in the course of performing the contention based random access. By the method, the contradiction between the SSB selection and the repeated judgment of the message 3 of the terminal equipment can be solved, and the time delay and the resource efficiency of the random access can be further considered.

Description

Random access method and device

Technical Field

Embodiments of the present application relate to the field of wireless communications, and in particular, to a method and apparatus for random access.

Background

With the development of communication technology and the improvement of user demands, terminal devices in a communication scene gradually exhibit a large number of characteristics, multiple forms and the like. For example, in an industrial automation scenario, there are a large number of monitoring devices, machines, or sensors, etc. in a factory building; in home and living scenarios, there are a large number of cell phones, tablets, wearable devices, smart home appliances, or vehicle-mounted terminal devices, etc. The random access process is an important process for establishing a wireless link between the terminal device and the network, so that the time delay of the random access process is reduced, and the improvement of the efficiency of the random access process becomes a problem to be solved.

Disclosure of Invention

The application provides a random access method and device, which are used for reducing the time delay of a random access process and improving the efficiency of the random access process.

In a first aspect, the present application provides a method for random access, where an execution body of the method is a terminal device. The method comprises the steps that a terminal device judges whether synchronous signals and physical broadcast channel blocks SSB with synchronous reference signal receiving power SS-RSRP higher than a first threshold value exist or not, wherein the first threshold value is preset by an access network device; the terminal equipment judges whether the condition of repeating the request message 3 is satisfied; if the condition that the request message 3 is repeated is met, and SSB that the SS-RSRP is higher than a first threshold exists, the terminal equipment executes non-competitive random access; or if the condition that the request message 3 is repeated is satisfied and there is an SSB in which the SS-RSRP is higher than a first threshold, the terminal device performs contention-based random access and performs message 3 repetition in 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 determination of message 3 repetition can be resolved. When the network load is higher and the time delay requirement is higher, the CFRA can be selected to be executed when the contradiction occurs, and the time delay of the terminal equipment to access the access network equipment is reduced by avoiding the collision of preamble and simplifying the steps of the random access process; when the network load is low and the requirement on the time delay is low, the random access resource is sufficient, and the CBRA can be selectively executed when the contradiction occurs. By implementing the method, the time delay and the resource efficiency of the random access can be considered.

In a possible implementation manner of the first aspect, the condition that the request message 3 is repeated is satisfied specifically includes: and the Reference Signal Receiving Power (RSRP) of the downlink reference signal is lower than a second threshold, wherein the second threshold is preset for the access network equipment.

In a possible implementation manner of the first aspect, the determining whether the condition for repeating the request message 3 is satisfied specifically includes: if there is no SSB for which the SS-RSRP is higher than the first threshold, it is determined whether the condition for repeating the request message 3 is satisfied. By implementing the method, if the terminal equipment judges to execute the CFRA when executing SSB selection, the repeated judgment of the message 3 is not needed to be executed; if the terminal device determines to execute CBRA when executing SSB selection, then the repeated determination of message 3 is executed again. Thereby, the contradiction between the execution of SSB selection and the repeated judgment of the message 3 in the terminal equipment can be avoided, and the random access efficiency is improved.

In a possible implementation manner of the first aspect, the terminal device determines whether there are random access resources supporting the repetition of the message 3 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; and the terminal equipment determines the repetition times of the message 3 corresponding to each SSB in a first SSB set according to the configuration information, wherein the first SSB set is part or all SSB of all SSB which can be detected by the terminal equipment.

In a possible implementation manner of the first aspect, the terminal device selects a first SSB from the first SSB set, and sends a random access preamble corresponding to the first SSB to the access network device on a physical random access channel opportunity RO resource 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 the message 3.

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

By implementing the method described in the second aspect, the terminal device can select the repetition number of the message 3 of the reporting request, and the access network device can also instruct the adjusted repetition number of the message 3 by sending the information, so that the terminal device can send the message 3 with the proper repetition number, thereby improving the reliability of random access and avoiding the waste of resources.

In a third aspect, a communication device is provided, comprising functional modules for implementing the method of the 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, there is provided a communication device comprising a processor and interface circuitry for receiving signals from or transmitting signals to the processor from or to other communication devices than the communication device, the processor being operable to implement the method of any of the foregoing first aspect, any of the possible implementations of the first aspect, the second aspect, any of the possible implementations of the second aspect by logic circuitry or executing code instructions.

In a fifth aspect, a communications apparatus is provided, comprising a processor and a memory, the processor being coupled to the memory, the processor being configured to control the apparatus to implement the method of any of the foregoing first aspect, any possible implementation of the first aspect, the second aspect, and any possible implementation of the second aspect.

In a sixth aspect, a computer readable storage medium is provided, in which a computer program or instructions is stored which, when executed, implement the method of the foregoing first aspect, any possible implementation of the first aspect, the second aspect, and any possible implementation of the second aspect.

A seventh aspect provides a computer program product comprising instructions which, when executed, implement the method of the foregoing first aspect, any possible implementation of the first aspect, the second aspect, any possible implementation of the second aspect.

In an eighth aspect, a computer program is provided, the computer program comprising code or instructions which, when executed, implement the method of the foregoing first aspect, any possible implementation of the first aspect, the second aspect, any possible implementation of the second aspect.

A ninth aspect provides a chip system comprising a processor and possibly a memory, implementing the method of the foregoing first aspect, any possible implementation manner of the first aspect, the second aspect, and any possible implementation manner of the second aspect. The chip system may be formed of a chip or may include a chip and other discrete devices.

Drawings

Fig. 1 is a schematic diagram of four-step random access based on contention according to an embodiment of the present application;

fig. 2 is a schematic diagram of two-step contention-based random access according to an embodiment of the present application;

fig. 3 is a schematic diagram of a non-contention based four-step random access method according to an embodiment of the present application;

fig. 4 is a schematic diagram of a non-contention based two-step random access according to an embodiment of the present application;

fig. 5, fig. 6, and fig. 7 are schematic flow diagrams of a data transmission method according to an embodiment of the present application;

fig. 8 and fig. 9 are schematic structural diagrams of a possible communication device according to an embodiment of the present application.

Detailed Description

The technical scheme provided by the embodiment of the application can be applied to various communication systems, for example: the long term evolution (long term evolution, LTE) system, a fifth generation (5th generation,5G) mobile communication system, a WiFi system, a future communication system, or a system in which multiple communication systems are integrated, etc., the embodiments of the present application are not limited. Wherein 5G may also be referred to as New Radio (NR).

The technical scheme provided by the embodiment of the application can be applied to various communication scenes, for example, one or more of the following communication scenes: enhanced mobile broadband (enhanced mobile broadband, eMBB), ultra-reliable low-latency communication (URLLC), machine type communication (machine type communication, MTC), large-scale machine type communication (massive machine type communications, mctc), device-to-device (D2D), vehicle-to-device (vehicle to everything, V2X), vehicle-to-vehicle (vehicle to vehicle, V2V), and internet of things (internet of things, ioT), among others.

In the embodiment of the present application, "/" may indicate that the associated object is an "or" relationship, for example, a/B may indicate a or B; "and/or" may be used to describe that there are three relationships associated with an object, e.g., a and/or B, which may represent: a exists alone, A and B exist together, and B exists alone. Wherein A, B may be singular or plural. In the embodiments of the present application, the words "first", "second", and the like may be used to distinguish between technical features that are the same or similar in function. The terms "first," "second," and the like do not necessarily denote any order of quantity or order of execution, nor do the terms "first," "second," and the like. In this application embodiment, the terms "exemplary" or "such as" and the like are used to denote examples, illustrations, or descriptions, and embodiments or designs described as "exemplary" or "such as" should not be construed as being preferred or advantageous over other embodiments or designs. The use of the word "exemplary" or "such as" is intended to present the relevant concepts in a concrete fashion to facilitate understanding.

The terminal device according to the 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 (UE) including a handheld device, an in-vehicle device, a wearable device, or a computing device with wireless communication capabilities. The UE may be a mobile phone, a tablet computer, or a computer with wireless transceiving function, for example. The terminal device may also be a virtual reality terminal device, an augmented reality terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned, a wireless terminal in telemedicine, a wireless terminal in smart grid, a wireless terminal in smart city, and/or a wireless terminal in smart home, etc.

In the embodiment of the present application, the device for implementing the function of the terminal device may be the terminal device; or a device, such as a chip system, capable of supporting the terminal device to implement the function, which may be installed in the terminal device or used in cooperation with the terminal device. In the embodiment of the application, the chip system may be formed by a chip, and may also include a chip and other discrete devices. In the technical solution provided in the embodiments of the present application, the device for implementing the function of the terminal device is an example of the terminal device, and the technical solution provided in the embodiments of the present application is described.

The access network device according to the embodiment of the present application includes a Base Station (BS), which may be a device deployed in a radio access network and capable of performing wireless communication with a terminal device. The base station may take many forms, such as macro base station, micro base station, relay station, access point, etc. The base station referred to in the embodiments of the present application may be a base station in a 5G system or a base station in an LTE system, where the base station in the 5G system may also be referred to as a transmission reception point (transmission reception point, TRP) or a next generation node B (generation Node B, gNB or gndeb). In the embodiment of the present application, the means for implementing the function of the access network device may be the access network device; or may be a device, such as a system-on-a-chip, capable of supporting the access network device to perform this function, which may be installed in or used in conjunction with the access network device. In the technical solution provided in the embodiments of the present application, taking the device for implementing the function of the access network device as an example of the access network device, the technical solution provided in the embodiments of the present application is described.

The following explains the related technical features related to the embodiments of the present application. It should be noted that these explanations are for easier understanding of the embodiments of the present application, and should not be construed as limiting the scope of protection claimed in the present application.

1. Random access

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

(a)CBRA

Step 1: the terminal device sends a preamble (also referred to as Msg 1) to the access network device, and the access network device acquires an ID (RAPID) of the preamble by detecting the preamble and estimates a transmission delay.

Step 2: the access network device replies an RAR (also referred to as Msg 2) to the terminal device, where the RAR carries a Time Advance (TA) corresponding to the transmission delay estimated in step 1, a time-frequency domain resource configured for transmission of the message 3 (also referred to as Msg 3) in step 3, and a temporary cell identifier (temporary cell radio network temporary identity, TC-RNTI), and so on.

Step 3, step 4: if multiple terminal devices transmit the same preamble using the same time-frequency domain resource in step 1, collision and contention may occur, and steps 3 and 4 are used for performing contention resolution. Specifically, after receiving an RAR corresponding to its RAPID, the terminal device adjusts uplink timing according to the TA therein, and sends a message 3 on the time-frequency domain resource allocated by the RAR, where the message 3 carries the identity of the terminal device. Then, the access network device replies a contention resolution message (message 4, which may also be referred to as Msg 4) to the terminal device, and if the terminal device receives the message 4 corresponding to its own identity, the random access procedure is successfully completed.

(b)CFRA

If the terminal device meets the CFRA condition, the terminal device uses the dedicated random access resource and preamble, and there is no contention conflict at this time, so step 3 and step 4 in CBRA do not need to be executed.

Wherein whether the terminal device performs CBRA or CFRA depends on triggering a random access event and the random access resources configured by the access network device for the terminal device. The event triggering CBRA may include:

(1) Terminal device initial access cell from radio resource control (radio resource control, RRC) idle state to RRC connected state

(2) RRC connection reestablishment

(3) The terminal equipment is in an RRC connected state, has uplink data arriving, but is in an uplink unsynchronized state or has no available physical uplink shared channel (physical uplink shared channel, PUSCH) resource transmission scheduling request (scheduling request, SR)

(4) SR transmission failure

(5) Terminal device from RRC inactive state to RRC connected state

Events that trigger CFRA may include:

(1) The terminal equipment is in RRC connection state, has downlink data to arrive, but is in uplink asynchronous state

(2) RRC-triggered synchronous reconfiguration, e.g. handover

(3) Establishing uplink synchronization between a terminal device and a secondary cell (SCell) after adding the SCell

(4) System message request

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

In the event of triggering CFRA, except event (3), CBRA is performed if CFRA conditions are not met, e.g. the access network device is not configured with CFRA resources.

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

The random access may include a four-step random access and a two-step random access.

In the four-step random access, the terminal equipment sends a preamble (preamble) to the access network equipment through a physical random access channel (physical random access channel, PRACH), namely, sends a message 1 to the access network equipment; after receiving the access preamble, the access network device sends a random access response (random access response, RAR) to the terminal device, that is, the access network device sends a message 2 to the terminal device, where the RAR may indicate the resource location of PUSCH; the terminal equipment sends a message 3 to the access network equipment through the PUSCH according to the resource position of the PUSCH indicated by the message 2; after receiving message 3, the access network device may send message 4 to the terminal device. Alternatively, the message 3 may include an RRC setup request (rrcsetup request) message or an RRC resume request (rrcresemerequest) message. Optionally, one or more of the following information may be included in the message 4: RRC setup (RRCSetup) message, RRC resume (rrcresse) message, acknowledgement/negative acknowledgement (negative acknowledgement, NACK) of PUSCH in message 3, and power control commands, etc. In the embodiment of the present application, "four-step random access" may also be referred to as: "4-step RACH" or "four-step RACH", the present embodiments do not limit the name.

In the two-step random access, the terminal equipment sends an access preamble (preamble) to the access network equipment through the PRACH, and sends uplink data to the access network equipment through the PUSCH, namely the terminal equipment sends a message A to the access network equipment; after receiving the message A, the access network device sends a message B to the terminal device. Alternatively, the message a may include an RRC setup request (rrcsetup request) message or an RRC resume request (rrcresemerequest) message. Optionally, one or more of the following information may be included in message B: RRC setup (RRCSetup) message, RRC resume (rrcrenule) message, ACK/NACK for PUSCH in message a, and power control commands, etc. In the embodiment of the present application, "two-step random access" may also be referred to as "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 procedure, the terminal device only transmits the preamble in the Msg1, and in the two-step random access procedure, the terminal device transmits uplink data in addition to the preamble in the MsgA.

As shown in fig. 1 to 4, the third generation partnership project (3rd Generation Partnership Project,3GPP) classifies the random access procedure into four kinds of: a four-step random access based on contention (hereinafter referred to as 4-step CBRA), a four-step random access based on non-contention (hereinafter referred to as 4-step CFRA), a two-step random access based on contention (hereinafter referred to as 2-step CBRA), and a two-step random access based on non-contention (hereinafter referred to as 2-step CFRA).

3. Random access initialization and resource selection

Before sending the preamble, the terminal device needs to perform random access initialization, and selects a carrier (NUL or SUL) for performing random access. Illustratively, if the access network device configures both NUL and SUL for the terminal device, the terminal device compares the reference signal received power (reference signal received power, RSRP) of the downlink reference signal with a threshold value RSRP-threshold ssb-SUL configured by the access network device, and if the RSRP is higher than the RSRP-threshold ssb-SUL, the terminal device performs random access on NUL, otherwise performs random access on SUL.

The terminal device needs to select a partial Bandwidth (BWP). The terminal device checks, for example, whether random access resources are available on the currently active upstream BWP, and if not, switches to BWP indicated by the parameter initiallinkbwp.

After the terminal device has selected the carrier and BWP, it needs to determine the type of random access (4-step random access or 2-step random access). Illustratively, if both 2-step random access resources and 4-step random access resources are configured on the selected BWP and the RSRP of the downlink reference signal is above a Threshold MsgA-RSRP-Threshold, the terminal device selects 2-step random access, otherwise 4-step random access is selected.

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

Illustratively, for the scenario of triggering CFRA, the access network device configures one or more synchronization signals and physical broadcast channel blocks (synchronization signal and physical broadcast channel block, SSB) for the terminal device to determine whether to perform CFRA, and if the terminal device determines that SSB with synchronization reference signal received power (synchronization signal reference signal received power, SS-RSRP) above threshold RSRP-threshold SSB exists in the configured one or more SSBs, the terminal device selects one SSB from SSBs with SS-RSRP above threshold RSRP-threshold SSB to perform CFRA.

4. Message 3 (Msg 3) repetition

Message 3 repetition is a coverage enhancement technique, and by repeating the transmission of message 3 multiple times in the random access process, the reliability of uplink transmission of users (especially cell edge users) is improved, so as to achieve the purpose of expanding uplink coverage.

Illustratively, the terminal device determines whether to request the 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 that requested the repetition of message 3.

The terminal device obtains the threshold configured by the access network device and used for judging whether the request message 3 needs to be repeated from the system message, and the threshold is denoted as rsrp-threshold msg3Rep in the embodiment of the application, and the name of the parameter is not limited in the embodiment of the application. In the process of random access initialization and resource selection, the terminal equipment compares the RSRP of the downlink reference signal with the RSrp-Threshold Msg3Rep, if the RSRP of the downlink reference signal is lower than the RSrp-Threshold Msg3Rep, the terminal equipment requests the access network equipment to execute the message 3 repetition, otherwise, the terminal equipment does not request the message 3 repetition.

The terminal device may group ROs and/or preambles according to parameters configured by the access network device, and the terminal device that requests and does not request the repetition of message 3 may select a different group of ROs and/or preambles for message 1 transmission.

The access network device determines whether the terminal device requests the message 3 to repeat according to the preamble and/or the RO of the transmission preamble sent by the terminal device. For the terminal equipment with repeated request message 3, the access network equipment informs the terminal equipment of the repeated times through RAR.

In the event of triggering the CFRA, for the CFRA triggered by the events (2) and (5), if the access network device configures resources of the 4-step CFRA for the terminal device, and at least one SS-RSRP of the configured SSBs is higher than the threshold RSRP-threshold SSB, the terminal device will execute the CFRA. CFRA may be performed if the terminal device performs selection of message 3 repetition prior to SSB selection and determines that request message 3 repetition is required, but finds that there is an SSB with SS-RSRP above a threshold RSRP-threshold SSB at SSB selection. And since there is no need to transmit message 3 in CFRA, the conclusion of whether message 3 is requested to repeat and the conclusion of SSB selection are contradictory. In addition, when the terminal device requests the message 3 to repeat, the access network device determines the number of times of the message 3 to repeat according to the channel quality estimated by the message 1 sent by the terminal device and indicates the number of times to the terminal device. Once the multi-user interference noise is large, or the preamble collision conflict occurs, the channel estimation error is large, at this time, the access network device may indicate an improper repetition number to the terminal device, if the repetition number is too large, the random access resource waste is caused, and if the repetition number is too small, the transmission failure is easily caused.

In view of this, the present invention provides a random access method for reducing the time delay of the random access process and improving the efficiency and reliability of the random access process.

Fig. 5 is a flow chart of a random access method provided in the embodiment of the present application, where the embodiment relates to a specific process of performing random access by an access network device and a terminal device. The execution body of the embodiment may be an access network device and a terminal device, or may be modules, such as chips, applied to the access network device and the terminal device, respectively. The following description will take an access network device and a terminal device as an execution body as an example.

As shown in fig. 5, the method may include: s501, S502 and S503, wherein S503 may be replaced by S503 a. The execution order of the steps is not limited in the embodiment of the present application, for example, S502 may be executed prior to S501.

S501, the terminal equipment judges whether the condition of repeating the request message 3 is satisfied. Illustratively, if the RSRP of the downlink reference signal is lower than a second threshold preset by the access network device, a condition that the request message 3 is repeated is satisfied; otherwise, if the RSRP of the downlink reference signal is higher than or equal to the second threshold preset by the access network device, the RSRP is not satisfied.

S502, the terminal equipment judges whether SSB with SS-RSRP higher than a first threshold exists. Optionally, the first threshold is preset for the access network device. In one possible way, the terminal device may determine, among one or more SSBs configured by the access network device for the terminal device, whether there is an SSB with an SS-RSRP above a first threshold. In another possible way, the terminal device may also determine whether there is an SSB with SS-RSRP higher than the first threshold among all SSBs that the terminal device can detect.

S503, if the condition that the request message 3 is repeated is satisfied, and there is an SSB with SS-RSRP higher than the first threshold, the terminal device executes CFRA. For example, if the condition that the request message 3 is repeated is satisfied and there is an SSB having an SS-RSRP higher than the first threshold among one or more SSBs configured by the access network device for the terminal device, the terminal device performs CFRA.

Illustratively, the terminal device selects one SSB from SSBs having SS-RSRP higher than a first threshold, then selects an RO and preamble corresponding to the selected SSB from random access resources configured by the access network device, and performs CFRA. Alternatively, the random access resource configured by the access network device may be a 4-step CFRA resource. The access network device illustratively configures the terminal device with 4-step CFRA resources on the BWP selected by the terminal device.

Alternatively, if the condition for requesting the message 3 repetition is not satisfied 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 the message 3 repetition.

Illustratively, the terminal device selects one SSB among all SSBs that the terminal device can detect, and selects a random access resource (RO and/or preamble) corresponding to the selected SSB from the set of random access resources repeatedly corresponding to the unsolicited message 3, and performs CBRA using the random access resource.

Alternatively, if the condition for requesting the repetition of message 3 is satisfied and there is no SSB with SS-RSRP higher than the first threshold, the terminal device performs CBRA and the terminal device performs message 3 repetition.

Illustratively, the terminal device selects one SSB among all SSBs that the terminal device can detect, and selects a random access resource (RO and/or preamble) corresponding to the selected SSB from the set of random access resources repeatedly corresponding to the request message 3, and performs CBRA using the random access resource.

Alternatively, if the condition for request message 3 repetition is not satisfied and there is an SSB with SS-RSRP higher than the first threshold, the terminal device performs CFRA.

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

Alternatively, S503 may be replaced by S503 a.

S503a, if the condition for requesting the repetition of message 3 is satisfied and there is an SSB with SS-RSRP higher than the first threshold, the terminal device performs CBRA, and in the process of performing CBRA, performs message 3 repetition.

Illustratively, the terminal device selects one SSB among SSBs whose SS-RSRP is higher than the first threshold, and selects a random access resource (RO and/or preamble) corresponding to the selected SSB from the set of random access resources repeatedly corresponding to the request message 3, and performs CBRA using the random access resource.

It is understood that in S503a, if the condition for message 3 repetition is satisfied, CBRA is performed, and in the process of performing CBRA, message 3 repetition is performed. That is, if the terminal device determines that the condition for message 3 repetition is satisfied, S502 may not be executed.

The above embodiments provide a random access method, which can solve the contradiction that occurs when a terminal device performs SSB selection and message 3 repetition judgment. When the network load is higher and the time delay requirement is higher, the CFRA can be selected to be executed when the contradiction occurs, and the time delay of the terminal equipment to access the access network equipment is reduced by avoiding the collision of preamble and simplifying the steps of the random access process; when the network load is low and the requirement on the time delay is low, the random access resource is sufficient, and the CBRA can be selectively executed when the contradiction occurs. By implementing the method, the time delay and the resource utilization rate of random access can be considered.

Fig. 6 is a flow chart of a random access method provided in the embodiment of the present application, where the embodiment relates to a specific process of performing random access by an access network device and a terminal device. The execution body of the embodiment may be an access network device and a terminal device, or may be modules, such as chips, applied to the access network device and the terminal device, respectively. The following description will take an access network device and a terminal device as an execution body as an example.

As shown in fig. 6, the method may include: s601, S602, S603, and S604. The execution sequence of each step is not limited in the embodiment of the present application.

S601, the terminal equipment judges whether SSB with SS-RSRP higher than a first threshold exists. Optionally, the first threshold is preset for the access network device. Alternatively, the terminal device may determine whether there is an SSB with SS-RSRP higher than the first threshold in one or more SSBs configured by the access network device for the terminal device. Alternatively, the terminal device may also determine whether there is an SSB with SS-RSRP higher than the first threshold value among all SSBs that the terminal device can detect.

S602, if SSB with SS-RSRP higher than a first threshold exists, executing S604; if there is no SSB with SS-RSRP higher than the first threshold, it is determined whether the condition for repeating the request message 3 is satisfied. Wherein, judging whether the condition of the request message 3 repetition is satisfied specifically includes: if the RSRP of the downlink reference signal is lower than a second threshold preset by the access network equipment, the condition that the request message 3 is repeated is met; otherwise, it is not satisfied.

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

If the condition for requesting the repetition of message 3 is not satisfied, the terminal device performs CBRA, and does not perform message 3 repetition in the process of performing CBRA.

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

The above embodiment provides a random access method, in which the terminal device performs SSB selection first, and then performs repeated judgment of the message 3. When SSB selection is executed, if the terminal equipment judges to execute CFRA, the repeated judgment of the message 3 is not executed; when SSB selection is performed, if the terminal device determines to perform CBRA, the repeated determination of message 3 is performed again. Thereby, the contradiction between the execution of SSB selection and the repeated judgment of the message 3 in the terminal equipment can be avoided, and the random access efficiency is improved.

Alternatively, in the embodiments shown in fig. 5 and 6, the terminal device determining whether there is an SSB with SS-RSRP higher than the first threshold may be replaced with: the terminal device determines whether a channel state information reference signal (channel state information reference signal, CSI-RS) having a channel state information reference signal received power (channel state information reference signal received power, CSI-RSRP) above a third threshold is present. Optionally, the third threshold is preset for the access network device. For example, the terminal device may determine whether there is a CSI-RS with a CSI-RSRP higher than a third threshold in one or more CSI-RS configured by the access network device for the terminal device.

Those skilled in the art will understand that in the embodiments shown in fig. 5 and 6, "SSB with SS-RSRP higher than the first threshold" may be replaced with "CSI-RS with CSI-RSRP higher than the third threshold" and "SSB without SS-RSRP higher than the first threshold" may be replaced with "CSI-RS without CSI-RSRP higher than the third threshold". That is, the determination that the terminal device performs the comparison of the SS-RSRP of the SSB with the first threshold may be replaced with the determination that the terminal device performs the comparison of the CSI-RSRP of the CSI-RS with the third threshold, the roles of both being identical.

Alternatively, the terminal device may determine whether there are random access resources supporting coverage enhancement on the active uplink BWP before performing the random access procedure.

If only the random access resource supporting coverage enhancement exists on the active uplink BWP, executing a first random access procedure; if the coverage enhanced random access resource is not supported on the active uplink BWP, performing a second random access procedure; if both the random access resources supporting coverage enhancement and the random access resources not supporting coverage enhancement are present on the active uplink BWP, any one or more of the embodiments S501 to S503a shown in fig. 5 are performed, or any one or more of the embodiments S601 to S605 shown in fig. 6 are performed.

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

Illustratively, if there are only random access resources on the active uplink BWP of the terminal device that support coverage enhancement, CBRA comprising message 3 repetition is performed when CBRA is triggered.

Optionally, the random access resources supporting coverage enhancement represent random access resources for performing the first random access procedure. That is, supporting coverage enhanced random access resources can also be understood as supporting message 3 repeated random access resources.

Alternatively, if no random access resource is configured on the active uplink BWP of the terminal device, or the number of times of coverage-enhanced random access resource and preamble transmission exceeds a threshold value on the active uplink BWP, the active uplink BWP is switched to the BWP indicated by the parameter initiallinkbwp, and any one of the embodiments S501 to S503a shown in fig. 5 is performed, or any one of the embodiments S601 to S605 shown in fig. 6 is performed.

Fig. 7 is a flow chart of a random access method provided in the embodiment of the present application, where the embodiment relates to a specific process of performing random access by an access network device and a terminal device. The execution body of the embodiment may be an access network device and a terminal device, or may be modules, such as chips, applied to the access network device and the terminal device, respectively. The following description will take an access network device and a terminal device as an execution body as an example.

As shown in fig. 7, the method may include: s701, S702, S703, S704 and S705, wherein S705 is optional. The execution sequence of each step is not limited in the embodiment of the present application.

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

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

Illustratively, 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 corresponds to the value of the repetition number of one message 3. Illustratively, one form of this configuration information is shown in Table 1.

Table 1 relationship between SS-RSRP value range and message 3 repetition number

SS-RSRP value range	Message 3 repetition times
		a～b	P
c～d	Q
		e～f	R

S703, the terminal equipment determines the first SSB and the number of message 3 repetition times corresponding to the first SSB according to the number of message 3 repetition times corresponding to each SSB in the first SSB set.

Illustratively, the terminal device selects one SSB from SSBs corresponding to the message 3 having the least number of repetitions, and determines the number of repetitions corresponding to the SSB. The terminal device selects one SSB from SSBs with the repetition number of the corresponding message 3 being less than or equal to a certain threshold, and determines the repetition number corresponding to the SSB, where the threshold may be preset by the access network device. Illustratively, the terminal device selects one of M SSBs with highest SS-RSRP, where M is a positive integer, and determines the number of repetitions corresponding to the SSB. The method for determining the first SSB by the terminal device is not limited in the embodiment of the present application.

S704, the terminal equipment sends a preamble corresponding to the first SSB to the access network equipment on RO resources 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 repetition number of the message 3 corresponding to the first SSB.

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

Illustratively, the first message includes two bits, as shown in table 2.

Table 2 an example of a first message

It is to be understood that table 2 is only an example, and the value and meaning of the first message are not limited in this embodiment of the present application. For example, the access network device divides the number of repetitions of the message 3 into 3 steps, which are 2,4,8, through the configuration information, and the first message may further indicate that the number of repetitions of the message 3 requested by the terminal device is reduced by 1. The number of message 3 repetitions reported by the terminal device is, for example, 8, and the access network device indicates, through the first message, that the adjusted number of message 3 repetitions is the gear of the number of message 3 repetitions requested by the terminal device minus 1, that is, the adjusted number of message 3 repetitions is 4.

The above embodiment provides a method for random access, where the terminal device may select the repetition number of the message 3 of the reporting request, and the access network device may also instruct the adjusted repetition number of the message 3 by sending the information, so that the terminal device may send the message 3 with an appropriate repetition number, thereby improving the reliability of random access and avoiding the waste of resources.

With respect to the embodiments of fig. 5 to 7, it should be noted that:

(1) The step numbers of the flowcharts described in the embodiments are only an example of the execution flow, and do not limit the execution sequence of the steps, and in the embodiments of the present application, there is no strict execution sequence between the steps without time sequence dependency relationship. Furthermore, not all the steps illustrated in the respective flowcharts are necessarily performed, and partial steps may be added or deleted on the basis of the respective flowcharts according to actual needs.

(2) The embodiments of fig. 5 to 7 described above may be implemented independently or may be combined with each other, for example, the embodiment of fig. 5 and the embodiment of fig. 7 are combined with each other, the embodiment of fig. 6 and the embodiment of fig. 7 are combined with each other, and so on.

(3) The above embodiments use messages and parameters in some 5G communication systems, but in implementations, different messages or message names may be used, which embodiments do not limit.

Fig. 8 to fig. 9 are schematic structural diagrams of possible communication devices according to embodiments of the present application. As shown in fig. 8, the communication apparatus 800 includes a processing unit 810 and a transceiving unit 820.

The communication apparatus 800 is configured to implement the functions of the first access network device in the method embodiments shown in fig. 5 to 7, or the communication apparatus 800 may include a module configured to implement any of the functions or operations of the first access network device in the method embodiments shown in fig. 5 to 7, which may be implemented in whole or in part by software, hardware, firmware, or any combination thereof.

When the communication apparatus 800 is used to implement the function of the terminal device in the method embodiment shown in fig. 5, the processing unit 810 is configured to determine whether the condition for repeating the request message 3 is satisfied; processing unit 810 is further configured to determine whether there is an SSB with SS-RSRP above a first threshold; if the condition that the request message 3 is repeated is satisfied and there is an SSB with SS-RSRP higher than the first threshold, the transceiver unit 820 is configured to perform CFRA; alternatively, if the condition that the request message 3 is repeated is satisfied and there is an SSB that the SS-RSRP is higher than the first threshold, the transceiving unit 820 is configured to perform CBRA, and in the process of performing CBRA, perform message 3 repetition.

When the communication apparatus 800 is configured to implement the function of the terminal device in the method embodiment shown in fig. 6, the processing unit 810 is configured to determine whether there is an SSB with an SS-RSRP higher than the first threshold; if there is an SSB with SS-RSRP higher than the first threshold, the processing unit 810 is further configured to determine whether the condition for repeating the request message 3 is satisfied; if the condition for requesting repetition of message 3 is satisfied, the transceiving unit 820 is configured to perform CBRA, and in the process of performing CBRA, message 3 repetition is performed.

When the communication apparatus 800 is used to implement the function 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 configured to determine, according to the configuration information, a number of repetitions of the message 3 corresponding to each SSB in the first SSB set; the processing unit 810 is further configured to determine the first SSB and the number of message 3 repetitions corresponding to the first SSB according to the number of message 3 repetitions corresponding to each SSB in the first SSB set; the transceiver 820 is further configured to send a preamble corresponding to the first SSB to the access network device on an RO resource corresponding to the first SSB; the transceiver unit 820 is further configured to receive a first message from the access network device, where the first message indicates the adjusted number of repetitions of the message 3.

The above-mentioned more detailed descriptions of the processing unit 810 and the transceiver unit 820 may be directly obtained by referring to the related descriptions in the method embodiments shown in fig. 5, fig. 6 or fig. 7, which are not repeated herein.

Fig. 9 is a schematic structural diagram of another possible communication device according to an embodiment of the present application. As shown in fig. 9, the 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 is 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 for storing input data required by the processor 910 to execute the instructions or for 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, 6, or 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 is to be appreciated that the processor in embodiments of the present application may be a central processing unit (Central Processing Unit, CPU), but may 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 arrays (Field Programmable Gate Array, FPGA) or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general purpose processor may be a microprocessor, but in the alternative, it may be any conventional processor.

The processor in embodiments of the present application may be in random access Memory (Random Access Memory, RAM), flash Memory, read-Only Memory (ROM), programmable ROM (PROM), erasable Programmable ROM (EPROM), electrically Erasable Programmable EPROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may reside in a network device or terminal device. The processor and the storage medium may reside as discrete components in a network device or terminal device.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed 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 apparatus. The computer program or instructions may be stored in or transmitted across 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 that integrates one or more available media. The usable medium may be a magnetic medium, e.g., floppy disk, hard disk, tape; but also optical media such as DVD; but also semiconductor media such as Solid State Disks (SSDs).

In the various embodiments of the application, if there is no specific description or logical conflict, terms and/or descriptions between the various embodiments are consistent and may reference each other, and features of the various embodiments may be combined to form new embodiments according to their inherent logical relationships.

It will be appreciated that the various numerical numbers referred to in the embodiments of the present application are merely for ease of description and are not intended to limit the scope of the embodiments of the present application. The sequence number of each process does not mean the sequence of the execution sequence, and the execution sequence of each process should be determined according to the function and the internal logic.

Claims

1. A method of random access, the method being applied to a terminal device or a chip in a terminal device, the method comprising:

judging whether synchronous signals and physical broadcast channel blocks SSB with synchronous reference signal receiving power SS-RSRP higher than a first threshold value exist or not, wherein the first threshold value is preset by access network equipment;

judging whether the repeated condition of the request message 3 is satisfied;

if the condition that the request message 3 is repeated is satisfied, and there is an SSB in which the SS-RSRP is higher than a first threshold, non-contention random access is performed, or contention-based random access is performed, and message 3 is repeated in the course of performing the contention-based random access.

2. The method according to claim 1, wherein the condition for satisfying the repetition of the request message 3 specifically comprises:

and the Reference Signal Receiving Power (RSRP) of the downlink reference signal is lower than a second threshold, wherein the second threshold is preset for the access network equipment.

3. The method according to claim 1 or 2, wherein the determining whether the condition for repeating the request message 3 is satisfied specifically comprises:

if there is no SSB for which the SS-RSRP is higher than the first threshold, it is determined whether the condition for repeating the request message 3 is satisfied.

4. A method according to any one of claims 1 to 3, further comprising:

it is determined whether there are random access resources supporting the repetition of message 3 on the active upstream partial bandwidth BWP.

5. The method according to any one of claims 1 to 4, further comprising:

receiving configuration information from the access network equipment;

and determining the repetition times of the message 3 corresponding to each SSB in a first SSB set according to the configuration information, wherein the first SSB set is part or all of SSBs of all SSBs which can be detected by the terminal equipment.

6. The method of claim 5, wherein the method further comprises:

and selecting a first SSB from the first SSB set, and sending a random access preamble corresponding to the first SSB to the access network equipment on a physical random access channel (RO) resource corresponding to the first SSB.

7. The method of claim 6, wherein the method further comprises:

a first message is received from the access network device, the first message indicating the number of repetitions of the adjusted message 3.

8. The method of claim 7, wherein the first message is carried on a random access response message.

9. A communication device, the device comprising:

a processing unit, configured to determine whether there are 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 an access network device;

the processing unit also judges whether the condition of repeating the request message 3 is satisfied;

and a transceiving unit, if the condition that the request message 3 is repeated is satisfied, and there is an SSB that the SS-RSRP is higher than a first threshold value, the transceiving unit is configured to perform non-contention random access, or perform contention-based random access, and perform message 3 repetition in the process of performing the contention-based random access.

10. The apparatus according to claim 9, wherein the condition for satisfying the repetition of the request message 3 specifically includes:

11. The apparatus according to claim 9 or 10, wherein the determining whether the condition for repeating the request message 3 is satisfied specifically comprises:

12. The apparatus according to any one of claims 9 to 11, wherein the processing unit is further configured to:

13. The device according to any one of claims 9 to 12, wherein,

the receiving and transmitting unit is further used for receiving configuration information from the access network equipment;

the processing unit is further configured to determine, according to the configuration information, a repetition number of a message 3 corresponding to each SSB in a first SSB set, where the first SSB set is part or all of SSBs that can be detected by the terminal device.

14. The apparatus of claim 13, wherein the device comprises a plurality of sensors,

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 random access preamble corresponding to the first SSB to the access network device on a physical random access channel opportunity RO resource corresponding to the first SSB.

15. The apparatus of claim 14, wherein the transceiver unit is further configured to:

16. The apparatus of claim 15, wherein the first message is carried on a random access response message.

17. A communication device comprising means for performing the method of any of claims 1 to 8.

18. A communication device comprising a processor and a memory, the processor and the memory being coupled, the processor being configured to control the device to implement the method of any one of claims 1 to 8.

19. A communication device comprising a processor and interface circuitry for receiving signals from other communication devices than the communication device and transmitting signals from the processor to the processor or sending signals from the processor to other communication devices than the communication device, the processor being configured to implement the method of any one of claims 1 to 8 by logic circuitry or executing code instructions.

20. A computer readable storage medium, characterized in that the storage medium has stored therein a computer program or instructions which, when executed by a communication device, implement the method of any of claims 1 to 8.

21. A computer program product comprising instructions which, when executed by a computer, implement the method of any one of claims 1 to 8.