CN113875311B

CN113875311B - Non-contention based two-step random access method, device, terminal and storage medium

Info

Publication number: CN113875311B
Application number: CN201980095149.3A
Authority: CN
Inventors: 石聪
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2023-12-05
Anticipated expiration: 2039-09-30
Also published as: WO2021062767A1; CN113875311A

Abstract

The application discloses a non-contention-based two-step random access method, a non-contention-based two-step random access device, non-contention-based two-step random access equipment and a storage medium, and belongs to the technical field of mobile communication. The method comprises the following steps: the UE sends a message A; the base station receives the message A; the base station judges whether the load transmitted in the PUSCH of the message A is successfully received or not; when the base station fails to successfully receive the load, a message B for retransmitting the load is sent; the terminal monitors the message B in a monitoring window of the message B; the terminal retransmits the load; when the base station successfully receives the load, the base station sends a message B for indicating the permission to access the base station; the terminal receives message B. According to the technical scheme provided by the application, the message B for realizing load retransmission is sent to the UE, and the load is retransmitted to the base station after the UE receives the message B, so that the load retransmission scheduling is realized, the non-contention-based two-step random access process is completed, and the access success rate of the non-contention-based two-step random process is improved.

Description

Non-contention based two-step random access method, device, terminal and storage medium

Technical Field

The present application relates to the field of mobile communications, and in particular, to a non-contention based two-step random access method, apparatus, terminal, and storage medium.

Background

RACH (Random Access Channel ) is a channel that is important in the initial access procedure between an access network device and a UE (User Equipment). LTE (Long-Term Evolution) uses a four-step random access mechanism based on non-contention, and is simplified to a two-step random access mechanism based on non-contention under certain usage scenarios in an NR (New Radio) system.

The two-step random access mechanism based on non-competition mainly comprises: the UE uses message a (MsgA) to send a random access preamble (preamble) and a payload (payload) to the access network device, and the access network device uses message B (MsgB) to send an access solution message to the UE. When the access network device only demodulates the random access preamble and fails to demodulate the load, the access network device needs to schedule retransmission of the load.

In the non-contention based four-step random access mechanism, the retransmission scheduling is based on TC-RNT1 (Temporary Cell Radio Network Temporary Identifier ), however, in the non-contention based two-step random access mechanism, the UE does not have TC-RNT1, so how to complete the retransmission scheduling of the load in the non-contention based two-step random access mechanism is a problem to be solved.

Disclosure of Invention

The embodiment of the application provides a non-contention based two-step random access method, a non-contention based two-step random access device, a terminal and a storage medium, which can solve the technical problem of how to finish load retransmission scheduling based on a non-contention based two-step random access mechanism in the related art. The technical scheme is as follows:

according to an aspect of the present application, there is provided a non-contention based two-step random access method, which is applied to a UE, the method comprising:

transmitting a message a, the message a comprising: a random access preamble, which is a random access preamble dedicated for the UE, and a payload transmitted on a PUSCH (Physical Uplink Shared Channel ) dedicated for the UE;

monitoring the message B in a monitoring window of the message B;

and retransmitting the load according to the message B.

According to an aspect of the present application, there is provided a non-contention based two-step random access apparatus, the apparatus comprising:

a sending module, configured to send a message a, where the message a includes: a random access preamble and a load, wherein the random access preamble is a random access preamble special for the UE, and the load is transmitted on a PUSCH special for the UE;

A monitoring module, configured to monitor, in a monitoring window of a message B, the message B;

and the retransmission module is used for retransmitting the load according to the message B.

According to one aspect of the application, a communication device includes a processor and a transceiver coupled to the processor; wherein:

the transceiver is configured to send a message a, where the message a includes: a random access preamble and a load, wherein the random access preamble is a random access preamble special for the UE, and the load is transmitted on an uplink shared channel (PUSCH) special for the UE;

the transceiver is configured to monitor, in a monitoring window of a message B, the message B;

the processor is configured to retransmit the load according to the message B monitored by the transceiver.

According to one aspect of the present application, there is provided a computer readable storage medium having stored therein at least one instruction, at least one program, a set of codes or a set of instructions, the at least one instruction, the at least one program, the set of codes or the set of instructions being loaded and executed by a processor to implement a non-contention based two-step random access method as described above.

According to one aspect of the present application, there is provided a chip comprising programmable logic and/or program instructions for implementing a non-contention based two-step random access method as described above when the chip is running.

According to one aspect of the present application, there is provided a computer program product comprising one or more computer programs which, when executed by a processor, are adapted to implement a non-contention based two-step random access method as described above.

The technical scheme provided by the application has at least the following technical effects:

when the base station fails to successfully receive the load of the message A in the non-contention based two-step random access process, the UE receives the message B and then retransmits the load to the base station according to the indication and the scheduling of the message B by sending the message B for scheduling uplink resources to realize the retransmission of the load to the UE, so that the retransmission scheduling of the load in the message A is realized, the non-contention based two-step random access process is completed, and the access success rate of the non-contention based two-step random process is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a block diagram of a communication system provided by an exemplary embodiment of the present application;

fig. 2 is a flowchart of a non-contention based two-step random access method according to an exemplary embodiment of the present application;

fig. 3 is a flowchart of a non-contention based two-step random access method according to another exemplary embodiment of the present application;

fig. 4 is a flowchart of a non-contention based two-step random access method according to still another exemplary embodiment of the present application;

fig. 5 is a flowchart of a non-contention based two-step random access method according to still another exemplary embodiment of the present application;

fig. 6 is a block diagram of a non-contention based two-step random access apparatus provided by an exemplary embodiment of the present application;

fig. 7 is a block diagram of a non-contention based two-step random access apparatus provided by another exemplary embodiment of the present application;

fig. 8 is a block diagram of a non-contention based two-step random access apparatus provided by yet another exemplary embodiment of the present application;

fig. 9 is a block diagram of a non-contention based two-step random access apparatus provided by still another exemplary embodiment of the present application;

fig. 10 is a block diagram of a communication device provided in an exemplary embodiment of the present application.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with aspects of the application as detailed in the accompanying claims.

Fig. 1 shows a block diagram of a communication system provided by an exemplary embodiment of the present application. As shown in fig. 1, the communication system may include: an access network 10 and a terminal 20.

The access network 10 comprises several access network devices 11. The access network 10 may be referred to as NG-RAN (New Generation-Radio Access Network) in a 5G NR system; the access network device 11 may be a base station, which base station 11 is a device deployed in the access network 10 to provide wireless communication functions for the terminal 20, and the base station 11 includes various forms of macro base stations, micro base stations, relay stations, access points, and so on. The names of base station capable devices may vary in systems employing different radio access technologies, for example in LTE systems, called eNB (evolved NodeB); in the 5G NR system, called gNodeB or gNB (next generation NodeB). As communication technology evolves, the description of "base station" may change. For convenience, the above-described devices for providing the terminal 20 with the wireless communication function are collectively referred to as access network devices.

The number of terminals 20 is typically a plurality and one or more terminals 20 may be distributed within the cell managed by each access network device 11. The terminal 20 may include various handheld devices, in-vehicle devices, wearable devices, computing devices, or other processing devices connected to a wireless modem, as well as various forms of UEs, MSs (Mobile Station), and the like, having wireless communication capabilities. For convenience of description, the above-mentioned devices are collectively referred to as a terminal. The access network device 11 and the terminal 20 communicate with each other via some over-the-air technology, e.g. the Uu interface.

In the communication process between the terminal 20 and the access network device 11, once the terminal 20 discovers a cell, it is possible to access the cell by connecting to the access network device 11 of the cell, and the process of connecting the terminal 20 to the access network device 11 is called a random access process. Assuming that cell a and cell B are different cells, when the terminal 20 enters cell B from cell a, it is necessary to switch the connection with the access network device 11 of cell a to the connection with the access network device 11 of cell B, and the process of switching the terminal 20 between different access network devices 11 is called a non-contention based random access process.

At present, the non-contention based random access procedure includes a non-contention based four-step random access procedure and a non-contention based two-step random access procedure, and the technical solution of the embodiment of the present application may be applied to the non-contention based two-step random access procedure, but may also be applied to other non-contention based random access procedures of subsequent evolution, which is not limited by the embodiment of the present application.

The "5G NR system" in the embodiment of the present application may also be referred to as a 5G system or an NR system, but the meaning thereof will be understood by those skilled in the art. The technical scheme described in the embodiment of the application can be applied to a 5G NR system and also can be applied to a subsequent evolution system of the 5G NR system, and the embodiment of the application is not limited to the above.

In the conventional non-contention based four-step random access mechanism, the UE transmits a message 1 including a random access preamble to the base station, the base station transmits a message 2 including a random access response to the UE after receiving the message 1, the UE transmits a message 3 including identity information (or other payload) to the base station after receiving the message 2, and the base station transmits a message 4 including an access resolution message to the UE after receiving the message 3. The identity information is a UE ID (User Equipment Identify, user equipment identity), for example, the UE ID may be a C-RNTI (Cell Radio Network Temporary Identifier, cell radio network temporary identity), a TC-RNTI, a RA-RNTI (Random Access Radio Network Temporary Identifier, random access radio network temporary identity), or the like.

In the non-contention based two-step random access scheme, the message 1 and the message 3 transmitted from the UE to the base station in the non-contention based four-step random access scheme may be combined into a message a, and the message 2 and the message 4 transmitted from the base station to the UE may be combined into a message B described below.

It should be noted that, in the following, the exemplary embodiments of the present application are only exemplified by taking the non-contention based random access method as the non-contention based two-step random access method and applying to the UE access base station, and after understanding the technical solution of the present application, those skilled in the art will easily think that other non-contention based random access methods in which the non-contention based random access method provided by the present application is the subsequent evolution, and applying to the case that other terminals access other access network devices, such as the MS access base station, etc., but these extensions should be included in the protection scope of the present application.

Referring to fig. 2, a flowchart of a non-contention based two-step random access method according to an exemplary embodiment of the present application is shown. The method can be applied to the system architecture shown in fig. 1. The method may comprise the following steps (201-208):

in step 201, the ue sends a message a.

Since a two-step random access mechanism based on non-contention is often used in a cell Handover procedure, the message a is mainly configured in a Handover (HO) command message, which is used to control the UE to perform a cell Handover, i.e. a connection between the UE and a base station of the cell a is switched to a connection between the UE and a base station of the cell B.

The message a includes: the method comprises the steps of random access lead codes and load, wherein the random access lead codes are special random access lead codes configured to UE by a network, the load is transmitted on a special uplink shared data channel (PUSCH) configured to the UE by a base station, and the load mainly comprises a switching command completion message and possibly some user plane data.

After the MAC layer generates the MAC PDU corresponding to the payload of the message a, the UE stores the MAC PDU (Media Access Control Protocol Data Unit, protocol data unit of the medium access control layer) in a fixed HARQ (Hybrid Auto Repeat Request, hybrid automatic repeat request) buffer (buffer), such as a message a buffer (or a message 3 buffer). The HARQ process number for transmitting the MAC PDU is a fixed HARQ process number, such as HARQ process ID 0.

In step 202, the base station receives message a.

Step 203, the base station determines whether to successfully receive the load transmitted in PUSCH of message a; if not, go to step 204; if so, step 207 is performed.

In step 204, when the base station fails to receive the payload, a message B for retransmitting the payload is sent.

After receiving the message a, the base station decodes or decodes the message a, and when the base station does not decode the PUSCH, that is, fails to receive the payload, the base station sends a message B for scheduling the retransmission of the payload to the UE. Message B is the response of the base station to message A, and is used for directly or indirectly scheduling uplink resources for retransmitting the load, thereby realizing the purpose of retransmitting the load.

It should be noted that, because the message a includes the UE-specific random access preamble, even if the base station fails to receive the payload transmitted in the PUSCH, that is, the base station fails to decode the payload transmitted in the PUSCH, the base station may identify the UE according to the message a, and obtain the C-RNTI of the UE. Thus, regardless of whether the base station can decode the payload transmitted in the PUSCH, the base station may send a message B to the UE, illustratively including a random access response and a random access method.

In step 205, the terminal listens for message B in the listening window of message B.

In the embodiment of the application, after the UE sends the message a, a listening window of the message B is started, and in the listening window of the message B, the UE can blindly detect the PDCCH (Physical Downlink Control Channel ), wherein the PDCCH is scrambled by the RNTI (Radio Network Temporary Identifier ), that is, the PDCCH is addressed by the RNTI.

It should be noted that, step 204 may be performed after step 201, after step 202, or after step 203, and that drawing step 204 after step 201 in fig. 2 is merely an exemplary description, which is not limited by the present application.

In step 206, the terminal retransmits the load.

After receiving the message B sent by the base station, the terminal can retransmit the load according to the uplink resource directly or indirectly scheduled by the message B, so as to complete the non-contention-based two-step random access process, i.e. the UE completes the cell switching.

In step 207, when the base station successfully receives the payload, a message B indicating that access to the base station is allowed is transmitted.

Illustratively, the message B for indicating that the access to the base station is allowed does not carry an UL grant.

In step 208, the terminal receives message B.

In summary, according to the technical scheme provided by the embodiment of the application, when the base station fails to successfully receive the load of the message A in the non-contention-based two-step random access process, the message B for scheduling uplink resources to realize load retransmission is sent to the UE, and the UE retransmits the load to the base station according to the indication of the message B and the scheduling after receiving the message B, so that the retransmission scheduling of the load in the message A is realized, the non-contention-based two-step random access process is completed, and the access success rate of the non-contention-based two-step random process is improved.

When the message B is used for scheduling retransmission of the load, there are at least three different implementations as follows:

1. the DCI in the message B is scrambled by adopting a C-RNTI, and the DCI schedules downlink transmission;

2. the DCI in message B is scrambled with an MsgB-RNTI (such as RA-RNTI) and the DCI schedules the downlink transmission.

3. The DCI in message B is scrambled with a C-RNTI and the DCI schedules uplink transmissions.

Three different implementations are set forth below.

For the first possible embodiment, as shown in fig. 3, the method may include the following steps:

in step 201, the ue sends a message a.

Since the two-step random access mechanism based on non-contention is mainly used in the RRC-connected cell Handover process, the message a is mainly configured in a Handover (HO) command message, and the Handover command is used to control the UE to perform cell Handover, i.e. to switch the connection between the UE and the base station of cell a to the connection between the UE and the base station of cell B.

The message a includes: the method comprises the steps of random access lead codes and load, wherein the random access lead codes are special random access lead codes configured to UE by a network, the load is transmitted on a special uplink shared data channel (PUSCH) configured to the UE by the network, and the load mainly comprises a switching command completion message and possibly some user plane data.

After the MAC layer generates a MAC PDU corresponding to the message a payload, the UE saves the MAC PDU in a fixed HARQ buffer, such as a message a buffer (or a message 3 buffer). The HARQ process number for transmitting the MAC PDU is a fixed HARQ process number, such as HARQ process ID 0.

In step 202, the base station receives message a.

Step 203, the base station determines whether to successfully receive the load transmitted in PUSCH of message a; if not, executing step 2041; if so, step 207 is performed.

In step 2041, the base station determines the C-RNTI of the UE according to the UE-specific random access preamble.

The C-RNTI is configured in the handover command. Since the random access preamble is a UE-specific preamble, the base station may determine a C-RNTI of the UE according to the UE-specific random access preamble, which may be used to address, i.e., scramble, the PDCCH.

In step 2042, the base station transmits a message B, where the message B is a PDCCH scrambled with a C-RNTI.

In the embodiment of the present application, the PDCCH includes DCI (Downlink Control Information, downlink control command), where the DCI is used for scheduling downlink transmission, and the DCI is downlink control information sent by the base station to the UE, and the DCI may be used for scheduling uplink transmission or downlink transmission.

When DCI is used for scheduling downlink transmission, a base station transmits downlink information to UE on downlink resources scheduled by the DCI; when the DCI is used to schedule uplink transmissions, the UE transmits uplink information to the base station on the uplink resources scheduled by the DCI.

In the embodiment of the application, DCI in PDCCH is used for scheduling downlink transmission.

Step 2051, the ue listens for message B in the listening window of message B;

the UE receives the message B, obtains DCI according to the PDCCH in the message B, and receives downlink data according to DCI scheduling.

After the UE finishes sending the message a, a listening window is started, in which the UE can blindly detect the PDCCH, in this embodiment of the present application, the PDCCH is scrambled with the C-RNTI, and the DCI included in the PDCCH includes a DA (Downlink Assignment, downlink allocation), and the PDSCH (Physical Downlink Shared Channel ) is scheduled in the DA.

In step 2043, the base station transmits MAC PDUs on the PDCCH scheduled downlink resources.

The base station transmits the MAC PDU on the downlink resource scheduled by the DCI in the PDCCH.

In step 2052, the ue receives and decodes the MAC PDU.

The content included in the MAC PDU is not limited in the embodiment of the present application, and illustratively, the MAC PDU may include TAC (Timing Alignment Command ), TAC and UL grant (Up Link grant), and backoff RAR (fallback RAR).

In one example, when the TAC and UL grant are included in the MAC PDU, the TAC and UL grant may be carried in the same MAC CE (Media Access Control Control Element, medium access control layer control unit) in the MAC PDU or in different MAC CEs in the MAC PDU. The TAC is a timing alignment command, which is used to align the time domain timing of the base station and the UE.

In one embodiment, the UL grant is used to schedule uplink resources for retransmission of the payload.

In another example, when the MAC PDU includes a backoff RAR, the backoff RAR is used to indicate that the UE needs to retransmit the load, and the backoff RAR includes at least UL grant, TAC, and TC-RNTI.

Illustratively, if the MAC PDU includes TAC and UL grant, or the MAC PDU includes a backoff RAR, it indicates that the UE needs to retransmit the payload.

In step 206, if the MAC PDU carries the UL grant, the UE retransmits the payload on the uplink resource scheduled by the UL grant.

After the UE decodes the MAC PDU, if the MAC PDU carries an UL grant, it indicates that the UE needs to retransmit the payload to the base station, and the UE retransmits the payload according to the uplink resource scheduled by the UL grant.

The MAC layer of the UE obtains the saved MAC PDU from the message a buffer (or message 3 buffer) that holds the payload and transmits the MAC PDU in the UL grant.

For example, the message B for indicating the base station is allowed to be accessed is also a PDCCH scrambled with a C-RNTI, and DCI in the PDCCH is used for scheduling downlink transmission.

For example, if the MAC PDU sent by the downlink transmission scheduled by the DCI includes TAC but does not include UL grant or fallback RAR, it indicates that the base station successfully receives the payload, and the UE does not need to retransmit the payload at this time, and after the UE clears the HARQ buffer for transmitting the payload, the non-contention-based two-step random access procedure can be completed.

In step 208, the terminal receives message B.

In summary, according to the technical solution provided in the embodiment of the present application, by carrying the PDCCH including the DCI in the message B, the base station transmits the MAC PDU on the downlink resource scheduled by the DCI, the UE decodes the MAC PDU after receiving the MAC PDU, and decides whether to retransmit the load according to the difference of contents included in the MAC PDU indicated by the decoding result, so as to provide a method for determining whether to need to retransmit the load, and if so, the UE retransmits the load to the base station to implement a two-step random access procedure based on non-contention.

In a second possible implementation manner, when the base station fails to receive the load based on the embodiment shown in fig. 3, steps 2041 to 2043 may alternatively be implemented as the above method, which may include the following steps, as shown in fig. 4:

in step 204a, the base station determines the msgB-RNTI (message B Radio Network Temporary Identifier, radio network temporary identity of message B) of the UE based on the UE-specific random access preamble.

The msgB-RNTI is a radio network temporary identity corresponding to message B. When the base station does not successfully receive the load, the base station determines an msgB-RNTI of the UE according to a random access time-frequency resource location of the UE for transmitting the dedicated random access preamble, and the msgB-RNTI may scramble the PDCCH. When the base station successfully receives the payload, the base station determines the C-RNTI of the UE according to the random access preamble special for the UE, and the C-RNTI can scramble the PDCCH. That is, the base station scrambles the PDCCH using the C-RNTI when successfully receiving the load; the base station scrambles the PDCCH using the msgB-RNTI when the payload is not successfully received.

In one embodiment, the msgB-RNTI is calculated in the same manner as the RA-RNTI. The RA-RNTI is a radio network temporary identity in a non-contention based four-step random access mechanism, and is determined by the PRACH (Physical Random Access Channel ) time-frequency resource location carrying message 1. When the calculating mode of the msgB-RNTI is the same as that of the RN-RNTI, the calculating formula of the msgB-RNTI is as follows:

Where s_id is an index (0.ltoreq.s_id < 14) of a first OFDM (Orthogonal Frequency Division Multiplexing ) symbol specifying PRACH (Physical Random Access Channel), t_id is an index (0.ltoreq.t_id < 80) of a first slot in a system frame specifying PRACH, f_id is a value (0.ltoreq.f_id < 8) of PRACH specified in an index frequency domain, ul_carrier_id is an UL (Uplink) carrier (0 represents NUL (Normal Uplink) carrier) for message A (or message 1) transmission, and 1 represents SUL (Supplementary Uplink ) carrier.

In step 204B, the base station transmits a message B, wherein the message B is a PDCCH scrambled with an MsgB-RNTI.

In step 205a, the UE monitors both the msgB-RATI scrambled PDCCH and the C-RNTI scrambled PDCCH in the listening window of message B.

After the UE sends the message a, it starts a listening window, in which the UE can blindly check the PDCCH. In the embodiment of the application, when the base station fails to successfully receive the load, the PDCCH is scrambled by adopting the msgB-RNTI, and when the base station successfully receives the load, the PDCCH is scrambled by adopting the C-RNTI. The UE monitors the PDCCH scrambled by the message msgB-RATI and the PDCCH scrambled by the C-RNTI in a monitoring window of the message B, if the UE monitors the PDCCH scrambled by the msgB-RNTI, the UE is required to retransmit the load; if the UE monitors the PDCCH scrambled by the C-RNTI, the network successfully receives the msgA.

The UE receives the message B, obtains DCI according to the PDCCH in the message B, and receives downlink data according to DCI scheduling. The DCI included in the PDCCH includes a DA, and the PDSCH is scheduled in the DA.

In step 204c, the base station transmits the MAC PDU on the downlink resource scheduled by the PDCCH.

In one example, when the TAC and UL grant are included in the MAC PDU, the TAC and UL grant may be carried in the same MAC CE (Media Access Control Control Element, medium access control layer control unit) in the MAC PDU or in different MAC CEs in the MAC PDU. The TAC is a time alignment command, which is used to align the time domain timing of the base station and the UE.

In contrast to the previous embodiment, the UE can determine whether the retransmission payload is needed according to the MsgB-RNTI without decoding the MAC PDU. If the base station successfully receives the load, the PDCCH in the message B is scrambled by adopting the C-RNTI; if the base station fails to receive the payload, the PDCCH in the message B is scrambled with the msgB-RNTI. When the UE receives the message B, it can determine whether the load needs to be retransmitted according to the scrambling mode of the PDCCH in the message B. If the UE needs to retransmit the load to the base station, the UE retransmits the load according to the uplink resource scheduled by the UL grant carried by the MAC PDU.

In summary, according to the technical scheme provided by the embodiment of the application, the PDCCH is scrambled in different manners according to whether the base station successfully receives the load, if the base station successfully receives the load, the C-RNTI is used for scrambling the PDCCH, and if the base station fails to successfully receive the load, the msgB-RNTI is used for scrambling the PDCCH, so that when the UE receives the message B comprising the PDCCH, whether the load needs to be retransmitted or not can be determined without decoding, and the speed of determining whether the load needs to be retransmitted or not is improved.

In a second possible embodiment, as shown in fig. 5, the above method comprises the following steps:

in step 201, the ue sends a message a.

After the MAC layer corresponds to generating the MAC PDU, the UE saves the MAC PDU in a fixed HARQ buffer, such as a message a buffer (or a message 3 buffer). The HARQ process number for transmitting the MAC PDU is a fixed HARQ process number, such as HARQ process ID 0.

In step 202, the base station receives message a.

Step 203, the base station determines whether to successfully receive the load transmitted in PUSCH of message a; if not, go to step 204A; if so, step 207 is performed.

In step 204A, the base station determines the C-RNTI of the UE based on the UE-specific random access preamble.

In step 204B, the base station transmits a message B, wherein the message B is a PDCCH scrambled with a C-RNTI.

In the embodiment of the present application, the PDCCH includes DCI for scheduling downlink transmission, where the DCI is downlink control information sent by the base station to the UE, and the DCI includes UL grant for scheduling uplink resources.

In one embodiment, the DCI may further include an instruction indicating uplink timing alignment, i.e., TAC.

In one example, when the HARQ process ID contained in the DCI is the same as the HARQ process ID used by the payload, the UE determines that the UL grant is used to schedule uplink resource retransmission of the payload, which is illustratively a fixed HARQ process ID.

In another example, a New Data Indication (NDI) is carried in the DCI, and when the new data indication is used to indicate retransmission, the UE determines that the UL grant is used to schedule the uplink resource retransmission payload. For example, when the bit value of NDI is 0, then the NDI is used to indicate retransmission; alternatively, when the bit value of the NDI is 1, the NDI is used to indicate retransmission. Note that the value inversion of NDI is not used here to indicate retransmission.

Step 205, the ue listens for message B in the listening window of message B;

After the UE finishes sending the message a, a listening window is started, in which the UE can blindly detect the PDCCH, in the embodiment of the present application, the PDCCH is scrambled by using the C-RNTI, and the DCI included in the PDCCH includes the UL grant.

In step 206, the ue retransmits the payload according to the UL grant scheduled uplink resource.

The payload transmitted in the PDSCH of message a is stored in a fixed HARQ buffer, such as the message a buffer.

The UE retransmits the payload on the UL grant scheduled uplink resource.

For example, the message B for indicating the base station is also a PDCCH scrambled with a C-RNTI, and the DCI in the PDCCH includes TAC.

In step 208, the terminal receives message B.

In summary, according to the technical solution provided in the embodiment of the present application, the UL grant is carried in the DCI, and the PDCCH including the DCI is included in the message B sent by the base station to the UE, so that after the UE receives the DCI, the UE retransmits the load according to the uplink resource scheduled by the UL grant in the DCI, and a load retransmission manner is extended, so as to complete the non-contention-based two-step random access procedure, and further improve the access success rate of the non-contention-based two-step random procedure.

In the above method embodiment, the technical solution of the present application is described only from the point of interaction between the base station and the UE. The steps performed by the base station may be implemented separately as a non-contention based two-step random access method on the base station side, and the steps performed by the UE may be implemented separately as a non-contention based two-step random access method on the UE side.

The following are examples of the apparatus of the present application that may be used to perform the method embodiments of the present application. For details not disclosed in the embodiments of the apparatus of the present application, please refer to the embodiments of the method of the present application.

Referring to fig. 6, a block diagram of a non-contention based two-step random access device according to an exemplary embodiment of the present application is shown. The apparatus 600 has a function of implementing the above-described method embodiment on the UE side, and the function may be implemented by hardware or may be implemented by executing corresponding software by hardware. The apparatus 600 may include: a transmitting module 610, a listening module 620 and a retransmitting module 630.

A sending module 610, configured to send a message a, where the message a includes: a random access preamble and a payload, wherein the random access preamble is a UE-specific random access preamble, and the payload is transmitted on a UE-specific uplink shared channel PUSCH.

A listening module 620, configured to listen to the message B in a listening window of the message B.

And a retransmission module 630, configured to retransmit the payload when the message B is used for scheduling retransmission of the payload.

In one embodiment, as shown in fig. 7, the apparatus 600 further includes a receiving module 640: the receiving module 640 is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH schedules downlink transmission; the retransmission module 630 is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant.

In one embodiment, as shown in fig. 7, the apparatus 600 further includes a receiving module 640: the receiving module 640 is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI and the PDCCH schedules downlink transmission; the retransmission module 630 is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant.

In one implementation, the msgB-RNTI is calculated in the same manner as the random access radio network temporary identity RN-RNTI.

In one embodiment, the MAC PDU further carries: timing alignment commands TAC.

In one embodiment, the TAC and the UL grant carry the same or different control units MAC CEs of the media access control layer in the MAC PDU; or, the TAC and the UL grant carry a back-off random access response RAR in the MAC PDU.

In one embodiment, the retransmission module 630 is further configured to: when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling uplink transmission, retransmitting the load according to an UL grant indicated by the PDCCH; the hybrid automatic repeat request HARQ process ID associated with the UL grant is the same as the fixed HARQ process ID used by the payload, or the PDCCH carries a new data indication, where the new data indication is used to indicate retransmission.

In summary, according to the technical scheme provided by the embodiment of the application, when the base station fails to successfully receive the load, the UE retransmits the load to the base station after receiving the message B by sending the message B for scheduling the uplink resource to realize the retransmission of the load to the UE, so that the retransmission scheduling of the load is realized, the non-contention-based two-step random access process is completed, and the access success rate of the non-contention-based two-step random process is improved.

Referring to fig. 8, a block diagram of a non-contention based two-step random access device according to an exemplary embodiment of the present application is shown. The apparatus 800 has a function of implementing the above-described method embodiment on the base station side, and the function may be implemented by hardware or may be implemented by executing corresponding software by hardware. The apparatus 800 may include: message receiving module 810, message sending module 820.

Message receiving module 810 is configured to receive a message a, where the message a includes: a random access preamble and a load, wherein the random access preamble is a UE-specific random access preamble, and the load is transmitted on a UE-specific uplink shared channel PUSCH;

and a message sending module 820, configured to send a message B when the payload is not successfully received, where the message B is used to schedule retransmission of the payload.

In one embodiment, as shown in fig. 9, the message sending module 820 includes: an identity determining module 821, configured to determine a cell radio network temporary identity C-RNTI of the UE according to the random access preamble; an information sending module 822, configured to send a message B, where the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI, and downlink control information DCI in the PDCCH is used to schedule downlink transmission; and the data sending module 823 is configured to receive a protocol data unit MAC PDU of the media access control layer according to the downlink resource scheduled by the PDCCH when the PDCCH schedules downlink transmission, where the MAC PDU carries an uplink scheduling grant UL grant.

In one embodiment, as shown in fig. 9, the message sending module 820 includes: an identification determining module 821, configured to determine a message B radio network temporary identifier msgB-RNTI of the UE according to the random access preamble; an information sending module 822, configured to send a message B, where the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI, and downlink control information DCI in the PDCCH is used to schedule downlink transmission; a data retransmission module 823, configured to receive a MAC PDU of a media access control layer from the downlink resource scheduled by the PDCCH, where the MAC PDU carries an uplink scheduling grant UL grant.

In one embodiment, the MAC PDU further carries: timing alignment commands TAC.

In one embodiment, the message sending module 820 includes: an identity determining module 821, configured to determine a cell radio network temporary identity C-RNTI of the UE according to the random access preamble; a data sending module 824, configured to send a message B, where the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI, the PDCCH is used for scheduling downlink transmission, and an UL grant indicated by the PDCCH is used for scheduling uplink transmission; the HARQ process ID associated with the UL grant is the same as the fixed HARQ process ID used by the payload, or the PDCCH carries a new data indication, where the new data indication is used to indicate retransmission.

It should be noted that, when the device provided in the embodiment of the present application implements the functions, only the division of the above functional modules is used for illustration, in practical application, the above functional allocation may be implemented by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to implement all or part of the functions described above. In addition, the apparatus and the method embodiments provided in the foregoing embodiments belong to the same concept, and specific implementation processes of the apparatus and the method embodiments are detailed in the method embodiments and are not repeated herein.

Referring to fig. 10, a block diagram of a communication device according to an exemplary embodiment of the present application is shown. For example, the communication device may be an access network device 11, such as a base station, in the block diagram of the communication system shown in fig. 1, for performing the above-mentioned base station-side non-contention based two-step random access method; the terminal 20, e.g. UE, in the block diagram of the communication system shown in fig. 1 may also be configured to perform the above-described UE-side non-contention based two-step random access method. Specifically, the present application relates to a method for manufacturing a semiconductor device.

The processor 1001 includes one or more processing cores, and the processor 1001 executes various functional applications and information processing by running software programs and modules.

The receiver 1002 and the transmitter 1003 may be implemented as a transceiver 1006, which may be a communication chip.

The memory 1004 is connected to the processor 1001 through a bus 1005.

Further, the memory 1004 may be implemented by any type of volatile or nonvolatile storage device or combination thereof, including but not limited to: RAM (Random-Access Memory) and ROM (Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash Memory or other solid state Memory technology, CD-ROM, DVD (Digital Video Disc, high density digital video disc) or other optical storage, tape cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Wherein:

the transceiver 1006 is configured to send a message a, where the message a includes: the method comprises the steps of randomly accessing a preamble and a load, wherein the random access preamble is the random access preamble special for the UE, and the load is transmitted on an uplink shared channel (PUSCH) special for the UE.

The transceiver 1006 is configured to monitor the message B in a listening window of the message B.

The processor 1001 is configured to retransmit the payload according to the message B monitored by the transceiver.

In one embodiment, the transceiver 1006 is configured to receive a protocol data unit MAC PDU of a media access control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling downlink transmission; the processor 1001 is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant.

In one embodiment, the transceiver 1006 is configured to receive a protocol data unit MAC PDU of a media access control layer according to downlink resources scheduled by a PDCCH when the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI and the PDCCH is used for scheduling downlink transmission; the processor 1001 is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant.

In one embodiment, the MAC PDU further carries: timing alignment commands TAC.

In one embodiment, the processor 1001 is configured to retransmit the payload according to an UL grant indicated by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling uplink transmission; the HARQ process ID associated with the UL grant is the same as the HARQ process ID used by the payload.

In one embodiment, the processor is configured to retransmit the payload according to an UL grant indicated by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling uplink transmission; the PDCCH carries a new data indication, and the new data indication is used for indicating retransmission.

In an embodiment of the present application, there is further provided a computer readable storage medium, where at least one instruction, at least one section of program, a code set, or an instruction set is stored, where the at least one instruction, the at least one section of program, the code set, or the instruction set is loaded and executed by the processor to implement the above-mentioned UE-side non-contention-based two-step random access method.

In an embodiment of the present application, there is further provided a computer readable storage medium, where at least one instruction, at least one section of program, a code set, or an instruction set is stored, where the at least one instruction, the at least one section of program, the code set, or the instruction set is loaded and executed by the processor to implement the above-mentioned two-step non-contention-based random access method on the base station side.

In an embodiment of the present application, a chip is further provided, where the chip includes a programmable logic circuit and/or program instructions, and when the chip operates, the chip is configured to implement a non-contention-based two-step random access method on the UE side as described above.

In the embodiment of the application, a chip is also provided, and the chip comprises a programmable logic circuit and/or program instructions, and is used for realizing the non-contention-based two-step random access method at the base station side when the chip runs.

In an embodiment of the present application, there is also provided a computer program product for implementing the above-mentioned non-contention based two-step random access method on the UE side when the computer program product is executed by a processor of the UE.

In an embodiment of the present application, there is also provided a computer program product for implementing the above-mentioned non-contention based two-step random access method at the base station side when the computer program product is executed by a processor of the base station.

It should be understood that references herein to "a plurality" are to two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship.

The foregoing description of the exemplary embodiments of the application is not intended to limit the application to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the application.

Claims

1. A non-contention based two-step random access method, wherein the method is applied to a user equipment UE, the method comprising:

Transmitting a message a, the message a comprising: a random access preamble and a load, wherein the random access preamble is a random access preamble special for the UE, and the load is transmitted on an uplink shared channel (PUSCH) special for the UE;

monitoring the message B in a monitoring window of the message B;

retransmitting the load according to the message B;

when the message B is used for scheduling the load to be retransmitted, retransmitting the load, including:

when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling downlink transmission, receiving a protocol data unit (MAC PDU) of a media intervention control layer according to downlink resources scheduled by the PDCCH; retransmitting the load on uplink resources scheduled by the UL grant when the uplink scheduling grant UL grant is carried in the MAC PDU; or alternatively, the first and second heat exchangers may be,

when the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI and the PDCCH is used for scheduling downlink transmission, receiving a protocol data unit (MAC PDU) of a media intervention control layer according to downlink resources scheduled by the PDCCH; and retransmitting the load on uplink resources scheduled by the UL grant when the uplink scheduling grant UL grant is carried in the MAC PDU.

2. The method of claim 1 wherein when the message B is the PDCCH scrambled by the msgB-RNTI, the msgB-RNTI is calculated in the same manner as the random access radio network temporary identity RN-RNTI.

3. The method according to claim 1 or 2, wherein the MAC PDU further carries: timing alignment commands TAC.

4. The method of claim 3, wherein the step of,

the TAC and the UL grant carry control units (MAC CEs) of the same or different media intervention control layers in the MAC PDU;

or alternatively, the first and second heat exchangers may be,

the TAC and the UL grant carry a back-off random access response RAR in the MAC PDU.

5. A non-contention based two-step random access device, the device comprising:

a sending module, configured to send a message a, where the message a includes: a random access preamble and a load, wherein the random access preamble is a random access preamble special for the UE, and the load is transmitted on an uplink shared channel (PUSCH) special for the UE;

a retransmission module, configured to retransmit the load according to the message B;

The apparatus further comprises a receiving module:

the receiving module is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling downlink transmission; the retransmission module is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant; or alternatively, the first and second heat exchangers may be,

the receiving module is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI and the PDCCH is used for scheduling downlink transmission; and the retransmission module is configured to retransmit the load on uplink resources scheduled by the UL grant when the MAC PDU carries the uplink scheduling grant UL grant.

6. The apparatus of claim 5, wherein when the message B is the PDCCH scrambled by the msgB-RNTI, the msgB-RNTI is calculated in the same manner as the random access radio network temporary identity RN-RNTI.

7. The apparatus according to claim 5 or 6, wherein the MAC PDU further carries: timing alignment commands TAC.

8. The apparatus of claim 7, wherein the device comprises a plurality of sensors,

or alternatively, the first and second heat exchangers may be,

9. A communication device comprising a processor and a transceiver coupled to the processor; wherein:

the processor is used for retransmitting the load according to the message B monitored by the transceiver;

the transceiver is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a cell radio network temporary identifier C-RNTI and the PDCCH is used for scheduling downlink transmission; the processor is configured to retransmit, when the MAC PDU carries an uplink scheduling grant UL grant, the payload on an uplink resource scheduled by the UL grant; or alternatively, the first and second heat exchangers may be,

The transceiver is configured to receive a protocol data unit MAC PDU of a media intervention control layer according to downlink resources scheduled by the PDCCH when the message B is a downlink control channel PDCCH scrambled by a message B radio network temporary identifier msgB-RNTI and the PDCCH is used for scheduling downlink transmission; and the processor is used for retransmitting the load on uplink resources scheduled by the UL grant when the uplink scheduling grant UL grant is carried in the MAC PDU.

10. The communication device according to claim 9, wherein when the message B is the PDCCH scrambled by the msgB-RNTI, the msgB-RNTI is calculated in the same manner as the random access radio network temporary identity RN-RNTI.

11. The communication device according to claim 9 or 10, wherein the MAC PDU further carries: timing alignment commands TAC.

12. The communication device of claim 11, wherein the communication device is configured to,

or alternatively, the first and second heat exchangers may be,

13. A computer readable storage medium having stored therein at least one instruction, at least one program, a set of codes, or a set of instructions, the at least one instruction, the at least one program, the set of codes, or the set of instructions being loaded and executed by a processor to implement the non-contention based two-step random access method according to any one of claims 1 to 4.