WO2019213974A1 - Method for message transmission in random access process and related device - Google Patents

Abstract

The embodiments of the present application provide a method for message transmission in a random access process and a related device. The method comprises: receiving downlink control information from a network device, the downlink control information comprising a modulation and coding scheme field, a first part of bits of the modulation and coding scheme field being used to indicate a first transport block size (TBS) for resending a scheduling transmission message concerning a random access; determining a target TBS according to the first TBS above; according to the target TBS, resending to the network device the scheduling transmission message concerning the random access. With the embodiments of the present application, the efficiency of message transmission in a random access process can be improved, the delay in message transmission can be reduced, the power consumption of message transmission can be reduced, and a strong applicability can be achieved.

Description

Method and related device for message transmission in random access process Technical field

The present application relates to the field of communications technologies, and in particular, to a method and related apparatus for message transmission in a random access procedure.

Background technique

The Internet of Things (IoT) is a "Internet of Things" that extends the Internet's client to any item and item, and exchanges and communicates information between any item and item. Also known as machine type communications (MTC). In order to meet the communication needs of MTC applications such as coverage enhancement, low speed, low cost and low energy consumption, research topics on how to support extremely low complexity and low cost Internet of Things in cellular networks have emerged. The research project was adopted in the 3rd generation partnership project (3GPP) of the Mobile Communications Standardization Organization and was established as the subject of narrowband internet of things (NB-IOT).

In the prior art, before the NB-IOT terminal device is connected to the network, random access is required through a random access channel (RACH), and radio resource control (RRC) is performed on the network device with the network side. Signaling interaction to establish an RRC link. After the terminal device establishes an RRC link with the network device, the service data communication is performed with the network device, and the terminal device completes the random access procedure to establish an RRC link, which takes a long time, and has multiple interaction signaling, and the terminal device communicates with the service data of the network device. The delay is large, the power consumption of the terminal device is high, and the applicability is poor.

Summary of the invention

The embodiment of the present invention provides a method and a related device for message transmission in a random access process, which can improve the efficiency of message transmission in a random access process, reduce the delay of message transmission, and reduce power consumption of message transmission, and the applicability is further improved. Strong.

In a first aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving downlink control information from a network device, where the downlink control information includes a modulation and coding scheme domain, and the modulation and coding scheme domain The first part of the bit is used to indicate that the first transport block size TBS of the random access scheduled transmission message is retransmitted, wherein the first TBS is one TBS in the candidate TBS set; the target TBS is determined according to the first TBS; The target TBS resends the scheduled access transmission message of the random access to the network device. In the embodiment of the present application, the TBS used for retransmitting the random access scheduling transmission message may be determined according to the TBS indicated by the partial bit of the modulation and coding scheme field in the downlink control information, and the retransmission random access scheduling transmission message is adopted. The TBS is determined in a more flexible manner. The TBS of the retransmission random access scheduling transmission message may be directly determined by the partial bits of the modulation and coding scheme field in the downlink control information, and the TBS of the retransmission random access scheduling transmission message is determined based on the TBS, thereby improving the random access procedure. The efficiency and reliability of message transmission are more applicable.

In a possible implementation manner, the first partial bit is located in a low bit of the modulation coding scheme field.

In a possible implementation manner, the first partial bit is located in a high bit of the modulation coding scheme field.

In a possible implementation manner, the bits other than the first partial bits in the above modulation and coding scheme field are filled with fixed bit values.

In the embodiment of the present application, the selection mode of the partial bit used to indicate the first TBS in the modulation and coding scheme field of the downlink control information is flexible, and the applicability is stronger.

In a possible implementation manner, the determining the target TBS according to the foregoing first TBS includes determining the foregoing first TBS as the target TBS. The operation is simple and the message transmission efficiency is high.

In a possible implementation manner, the first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of a scheduled transmission message for performing random access using a candidate TBS that is less than or equal to the first TBS is allowed to be used. The determining the target TBS according to the foregoing first TBS includes selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS. The selection method of the TBS used for the retransmission of the random access scheduling message is more flexible. The terminal device can select the TBS that is closest to the uplink service data, avoiding waste of resources, and reducing the power consumption of the uplink transmission.

In a possible implementation manner, the first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of a scheduled transmission message that is less than or equal to the candidate TBS of the first TBS for random access is not allowed. The determining the target TBS according to the first TBS described above includes determining the first TBS as the target TBS. The method for determining the TBS used for retransmission of the scheduled transmission message of the random access is simpler, thereby avoiding unnecessary blind detection when scheduling the transmission of the message and saving resources.

In the embodiment of the present application, part of the bits of the modulation and coding scheme field in the downlink control information may jointly indicate the first TBS allowed to be used for retransmitting the scheduled transmission message of the random access, and may also indicate whether the allowed use is less than the allowed use. The other TBSs of the first TBS perform message transmission, which increases the diversity of the selection manner of the TBS used for retransmitting the random access scheduled transmission message, and improves the transmission efficiency of the uplink service data in the random access process.

In a possible implementation manner, the foregoing modulation and coding scheme domain further includes a second partial bit, where the second partial bit is used to indicate that a scheduled transmission message that is less than or equal to the candidate TBS of the first TBS is used for random access. Resend. The determining the target TBS according to the first TBS includes selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.

In a possible implementation manner, the foregoing modulation and coding scheme field further includes a second partial bit, where the second partial bit is used to indicate that the scheduled transmission message that is less than or equal to the candidate TBS of the first TBS for random access is not allowed to be used. Resend. The determining the target TBS according to the first TBS described above includes determining the first TBS as the target TBS.

In the embodiment of the present application, the first part of the bits of the modulation and coding scheme field in the downlink control information may indicate the first TBS that is allowed to be used for retransmitting the scheduled transmission message of the random access, and the second part of the bit may indicate whether the use is allowed to be less than The other TBSs of the first TBS that are allowed to use the message transmission, which increases the diversity of the indication manner of the TBS that is allowed to be used for retransmitting the random access scheduling transmission message, thereby also increasing the scheduling transmission message of the retransmission random access. The diversity of selection methods of the used TBS can improve the transmission efficiency of uplink service data in the random access process.

In a possible implementation, before receiving the downlink control information from the network device, receiving the system message sent by the network device, where the system message includes configuration information, where the configuration information is used to indicate whether the use of the first TBS is less than or equal to the first TBS. The candidate TBS performs retransmission of the scheduled transmission message for random access.

In a possible implementation manner, when the foregoing configuration information is used to indicate that retransmission of a scheduled transmission message that is less than or equal to the candidate TBS of the first TBS for random access is allowed, the target TBS is determined according to the foregoing first TBS. And selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.

In a possible implementation manner, when the foregoing configuration information is used to indicate that retransmission of a scheduled transmission message that is less than or equal to the candidate TBS of the first TBS for random access is not allowed, the foregoing determining the target according to the foregoing first TBS The TBS includes determining the first TBS described above as a target TBS.

In the embodiment of the present application, the configuration information in the system message may indicate whether to allow other TBSs that are smaller than the allowed first TBS to perform message transmission, which may save downlink control information signaling overhead and increase retransmission random access. The diversity of the indication manner of the TBS allowed by the scheduling transmission message, thereby increasing the diversity of the selection manner of the TBS used for retransmitting the random access scheduling transmission message, and the scope of application is wider.

In a possible implementation manner, when the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used may be determined as the target TBS. Here, the TBS actually required to be used may be a TBS used for initially transmitting a random access scheduled transmission message to the network device.

In a possible implementation manner, when the first TBS is smaller than the TBS actually required to be used, the TBS of the communication protocol specified size may be determined as the target TBS.

In a possible implementation manner, when the first TBS is smaller than the TBS actually needed to be used, the first TBS may be determined as the target TBS.

In the embodiment of the present application, the TBS of the retransmission random access scheduling transmission message may be determined according to the first TBS indicated by the network device and the TBS actually required to be used in the random access process, thereby ensuring scheduled transmission of random access. The reliability of the transmission of the message.

In a second aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving downlink control information from a network device, where the downlink control information is used to indicate resending a scheduled transmission message of a random access. The first transport block size is TBS. Determining a target TBS according to the foregoing first TBS; resending a scheduled access transmission message of the random access to the network device according to the foregoing target TBS.

In a possible implementation manner, when the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used may be determined as the target TBS.

In a possible implementation manner, when the first TBS is smaller than the TBS actually required to be used, the TBS of the communication protocol specified size may be determined as the target TBS.

In a possible implementation manner, when the first TBS is smaller than the TBS actually needed to be used, the first TBS may be determined as the target TBS.

In the embodiment of the present application, the TBS of the retransmission random access scheduling transmission message may be determined according to the first TBS indicated by the network device and the TBS actually required to be used in the random access process, thereby ensuring scheduled transmission of random access. The reliability of the transmission of the message.

In a third aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving downlink control information from a network device, where the downlink control information is used to indicate resending a scheduled transmission message of a random access. The second transport block size is TBS. Determining a first TBS according to the foregoing second TBS, and determining a target TBS according to the foregoing first TBS; and resending a scheduled access transmission message of the random access to the network device according to the target TBS.

In a possible implementation manner, determining, according to the foregoing second TBS, that the first TBS includes, by the terminal device, selecting a candidate TBS that is closest to the second TBS value from the candidate TBS set according to the second TBS, or from the candidate TBS set. Selecting a candidate TBS that is closest to the second TBS value and larger than the second TBS, or selects a candidate TBS that is closest to the second TBS value and smaller than the second TBS from the candidate TBS set. The selected candidate TBS is taken as the first TBS.

In a possible implementation manner, when the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used may be determined as the target TBS.

In a possible implementation manner, when the first TBS is smaller than the TBS actually required to be used, the TBS of the communication protocol specified size may be determined as the target TBS.

In a possible implementation manner, when the first TBS is smaller than the TBS actually needed to be used, the first TBS may be determined as the target TBS.

In the embodiment of the present application, the first TBS may be determined according to the second TBS indicated by the network device in the random access process, and the TBS of the retransmitted random access scheduled transmission message is determined according to the first TBS and the TBS actually needed to be used. Thereby, the transmission reliability of the scheduled transmission message of the random access can be guaranteed.

In a fourth aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving a system message broadcasted by a network device, and determining, according to the system message, a maximum transport block size TBS that is allowed to be used; The network device receives the downlink control information, where the downlink control information includes a modulation and coding scheme field, where a part of the bits of the modulation and coding scheme field is used to indicate whether to allow a scheduled transmission message that is less than or equal to the candidate TBS of the maximum TBS to perform random access. Resend. Determining a target TBS according to the indication of the maximum TBS and the partial bits of the modulation and coding scheme field; and resending the scheduled access transmission message of the random access to the network device according to the target TBS. In the embodiment of the present application, a part of the bits of the modulation and coding scheme field in the downlink control information may directly indicate whether the terminal device retransmits the randomly scheduled scheduling transmission message to allow use of a certain TBS that is smaller than the maximum TBS broadcast by the system message. The message transmission is performed without indicating the first TBS that is allowed to be used, and the diversity of the selection manner of the TBS used by the terminal device to retransmit the scheduled transmission message of the random access is increased, and the bits occupying the modulation and coding scheme field are also saved. save resources.

In a possible implementation manner, when the partial bit indicates that the candidate TBS less than or equal to the maximum TBS is not allowed to perform retransmission of the scheduled transmission message, the maximum TBS may be determined as the target TBS.

In a possible implementation manner, when the foregoing partial bit indicates that the candidate TBS that is less than or equal to the maximum TBS is allowed to perform retransmission of the scheduled transmission message, the candidate TBS set may be determined according to the size of the maximum TBS, where the candidate is At least one candidate TBS is included in the TBS set. A candidate TBS less than or equal to the maximum TBS is selected from the candidate TBS sets, and the selected candidate TBS is determined as the target TBS.

In a fifth aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving downlink control information from a network device; and interpreting the terminal device before resending the scheduled transmission message of the random access Each of the above downlink control information except the modulation coding scheme domain. Resending the scheduled transmission message of the random access to the network device according to the scheduling information of each domain and the target transmission block size TBS, where the target TBS is used for transmitting the scheduled transmission message of the random access to the network device for the first time. TBS.

In a possible implementation manner, the foregoing candidate TBS set is determined by the network device by using the maximum allowed TBS indicated by the system message;

The size of each candidate TBS in the candidate TBS set is less than or equal to the size of the maximum TBS.

In a possible implementation manner, the foregoing candidate TBS set is determined by the network device by using the maximum TBS and the number of candidate TBSs that are allowed to be indicated by the system message;

The candidate TBS set includes N candidate TBSs, and the size of each candidate TBS in the N candidate TBSs is less than or equal to the size of the maximum TBS.

In the embodiment of the present application, before the terminal device resends the scheduled transmission message of the random access, each domain except the modulation and coding scheme field in the downlink control information may be interpret, that is, the scheduling of the modulation and coding scheme domain in the DCI may not be performed. The information is interpreted, thereby saving the signaling overhead of transmitting data in the random access process, improving the efficiency and reliability of data transmission during the random access process, and being more applicable.

In a sixth aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: receiving downlink control information from a network device, where the downlink control information includes a modulation and coding scheme domain, and the modulation and coding scheme domain. The partial bits are used to indicate the first transport block size TBS that is allowed to be used for resending the scheduled transmission message. If the first TBS is smaller than the actual TBS to be used, the random access is re-initiated after the random access is re-initiated or the contention timing of the random access is timed out. In the embodiment of the present application, the retransmission of the scheduled transmission message of the random access may be determined according to the TBS actually used, so that the reliability of the message transmission is ensured, and the applicability is stronger.

In a seventh aspect, the embodiment of the present application provides a method for transmitting a message in a random access process, where the method includes: sending downlink control information to a terminal device, where the downlink control information includes a modulation and coding scheme domain, and the modulation and coding scheme domain. The first part of the bit is used to indicate that the first transport block size TBS of the random access scheduled transmission message is retransmitted, the first TBS is one TBS in the candidate TBS set; and the foregoing first TBS receives the foregoing retransmission of the terminal equipment according to the foregoing Random access scheduling transmission messages.

In a possible implementation, the receiving, by the first TBS, the scheduled transmission message of the random access that is retransmitted by the terminal device according to the foregoing, the receiving, by the first TBS, receiving, by using the first TBS, the scheduled transmission message of the random access. In the embodiment of the present application, the TBS used for retransmitting the random access scheduling transmission message may be based on a partial bit indication of the modulation and coding scheme field in the downlink control information, and may prevent the random access scheduled transmission message from being received. Unnecessary blind detection can improve the efficiency and reliability of message transmission in the random access process, and the applicability is stronger.

In a possible implementation, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed by using a candidate TBS that is less than or equal to the first TBS. The scheduling transmission message of the random access that is retransmitted by the terminal device according to the foregoing first TBS includes: determining, by the first candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a scheduled transmission message. The TBS set is detected, and the scheduled transmission message of the random access is received and processed according to the one or more candidate TBSs.

In a possible implementation, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed. The receiving, according to the foregoing first TBS, the scheduled transmission message of the random access retransmitted by the terminal device, includes: receiving, according to the first TBS, the scheduled transmission message of the random access.

In the embodiment of the present application, part of the bits of the modulation and coding scheme field in the downlink control information may jointly indicate the first TBS allowed to be used for retransmitting the scheduled transmission message of the random access, and may also indicate whether the allowed use is less than the allowed use. The other TBSs of the first TBS perform message transmission, which increases the diversity of the selection manner of the TBS used for retransmitting the random access scheduled transmission message, and improves the transmission efficiency of the uplink service data in the random access process.

In a possible implementation, the foregoing modulation and coding scheme field further includes a second partial bit, where the second partial bit is used to indicate that the scheduled transmission message of the random access is allowed to be used by using the candidate TBS that is less than or equal to the first TBS. Resend. The scheduling transmission message of the random access that is retransmitted by the terminal device according to the foregoing first TBS includes: determining, by the first candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a scheduled transmission message. The TBS set is detected, and the scheduled transmission message of the random access is received and processed according to the one or more candidate TBSs.

In a possible implementation manner, the foregoing modulation and coding scheme field further includes a second partial bit, where the second partial bit is used to indicate that retransmission of the scheduled transmission message by using the candidate TBS that is less than or equal to the first TBS is not allowed. The receiving, according to the foregoing first TBS, the scheduled transmission message of the random access retransmitted by the terminal device, includes: receiving, according to the first TBS, the scheduled transmission message of the random access.

In the embodiment of the present application, the first part of the bits of the modulation and coding scheme field in the downlink control information may indicate the first TBS that is allowed to be used for retransmitting the scheduled transmission message of the random access, and the second part of the bit may indicate whether the use is allowed to be less than The other TBSs of the first TBS that are allowed to use the message transmission, which increases the diversity of the indication manner of the TBS that is allowed to be used for retransmitting the random access scheduling transmission message, thereby also increasing the scheduling transmission message of the retransmission random access. The diversity of selection methods of the used TBS can improve the transmission efficiency of uplink service data in the random access process.

In an eighth aspect, the embodiment of the present application provides a method for message transmission in a random access process, where the method includes: broadcasting a system message to a terminal device, where the system message is used to instruct the terminal device to resend the scheduled transmission message of the random access. The maximum transport block size TBS allowed. Transmitting the downlink control information to the terminal device, where the downlink control information includes a modulation and coding scheme field, where a part of the bits of the modulation and coding scheme field is used to indicate whether to allow scheduling of the random access by using a candidate TBS that is less than or equal to the maximum TBS. Retransmission of the transport message; receiving, according to the indication of the partial bit and the maximum TBS, the scheduled transmission message of the random access retransmitted by the terminal device.

In a possible implementation manner, the foregoing partial bits are used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the maximum TBS is not allowed. And the foregoing scheduling, based on the indication of the partial bit and the receiving, by the maximum TBS, the scheduled transmission message of the random access retransmitted by the terminal device, to perform receiving processing on the scheduled transmission message of the random access according to the maximum TBS.

In a possible implementation manner, the foregoing partial bits are used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed by using the candidate TBS that is less than or equal to the maximum TBS. And the scheduling transmission message of the random access that is retransmitted by the terminal device by the foregoing maximum TBS, and the determining, by the foregoing maximum TBS, the candidate TBS set corresponding to the maximum TBS as the blind detection of the scheduled transmission message of the random access. The TBS is set, and the scheduled transmission message of the random access is received according to the candidate TBS in the candidate TBS set.

The ninth aspect, the embodiment of the present application provides a terminal device, where the terminal device includes any possible implementation manner of any one of the foregoing first to fifth aspects, and/or any one of the aspects, The method unit and/or module of the message transmission in the provided random process, and thus the beneficial effects (or advantages) of the method for message transmission in the random process provided by any of the first to fifth aspects can be achieved. .

In a tenth aspect, the embodiment of the present application provides a network device, where the network device includes any possible implementation manner of any one of the sixth aspect to the seventh aspect, and/or any one of the foregoing aspects. The method unit and/or module for message transmission in a random process is provided, and thus the beneficial effects (or advantages) of the method for message transmission in the random process provided by the sixth aspect or the seventh aspect can be achieved.

In an eleventh aspect, an embodiment of the present application provides a terminal device, where the terminal device includes a memory, a transceiver, and a processor; wherein the memory, the transceiver, and the processor are connected by using a communication bus. The memory is for storing a set of program code, the transceiver and the processor for calling the program code stored in the memory to perform any one of the first to fifth aspects and/or any one of the above aspects The implementation method, the method for message transmission in the random process provided, can also achieve the beneficial effects of the method for message transmission in the random process provided by any one of the first aspect to the fifth aspect.

In a twelfth aspect, the embodiment of the present application provides a network device, where the network device includes a memory and a transceiver processor; wherein the memory and the transceiver processor are connected by using a communication bus. The memory is for storing a set of program code, the transceiver processor for calling the program code stored in the memory to perform any one of the sixth aspect to the seventh aspect and/or any one of the possible implementations The method for message transmission in a random process provided by the method can also achieve the beneficial effects of the method for message transmission in the random process provided by the sixth aspect or the seventh aspect.

In a thirteenth aspect, the embodiment of the present application provides a computer readable storage medium, where the computer readable storage medium stores an instruction, when the instruction is run on the terminal device, causing the terminal device to perform the first aspect to the first Any of the five aspects and/or any one of the possible implementations of any of the aspects, the method for transmitting a message in a random process, or the method of any of the first aspect to the fifth aspect The beneficial effects of the method of message transmission in a random process.

In a fourteenth aspect, the embodiment of the present application provides a computer readable storage medium, where the computer readable storage medium stores an instruction, when the instruction is run on a network device, causing the network device to perform the sixth aspect to the foregoing The method for transmitting a message in a random process provided by any one of the seven aspects and/or any one of the possible implementations of any of the aspects can also implement the message transmission in the random process provided by the sixth aspect or the seventh aspect The beneficial effects of the method.

In a fifteenth aspect, the embodiment of the present application provides a communication device, which may be a chip or a plurality of chips working in cooperation, and the communication device includes an input device coupled to a communication device (eg, a chip) for The technical solution provided by any one of the first aspect to the fifth aspect, and/or any one of the possible implementation manners of any one of the embodiments. It should be understood that "coupled" herein means that two components are combined directly or indirectly with each other. This combination may be fixed or movable, which may allow for the transfer of fluid, electrical, electrical or other types of signals between the two components.

In a sixteenth aspect, the embodiment of the present application provides a communication device, which may be a chip or a plurality of chips working together, and the communication device includes an input device coupled to a communication device (eg, a chip) for The technical solution provided by the sixth aspect or the seventh aspect of the embodiment of the present application is implemented. It should be understood that "coupled" herein means that two components are combined directly or indirectly with each other. This combination may be fixed or movable, which may allow for the transfer of fluid, electrical, electrical or other types of signals between the two components.

In a seventeenth aspect, the embodiment of the present application provides a communication system, including a transceiver and a processor, the transceiver and the processor are configured to be coupled to a memory, and read and run instructions in the memory to support random access. The apparatus for process message transmission implements the functions involved in any of the above first to fifth aspects, for example, the method of generating or processing the message transmission in the random process provided by any of the above first to fifth aspects The information involved. In one possible design, the communication system further includes a memory for storing program instructions and data necessary for the device for random access procedure message transmission. The communication system can be composed of chips, and can also include chips and other discrete devices.

In an eighteenth aspect, the embodiment of the present application provides a communication system, including a transceiver processor, configured to be coupled to a memory, to read and run instructions in the memory for supporting a random access procedure message. The transmitting device implements the functions involved in the sixth aspect or the seventh aspect described above, for example, generating or processing information involved in the method of message transmission in the random process provided by the sixth aspect or the seventh aspect. In one possible design, the communication system further includes a memory for storing program instructions and data necessary for the device for random access procedure message transmission. The communication system can be composed of chips, and can also include chips and other discrete devices.

In a nineteenth aspect, the embodiment of the present application provides a computer program product comprising instructions, when the computer program product is run on a terminal device, causing the terminal device to perform the foregoing any one of the first aspect to the fifth aspect The method of message transmission in a random process can also achieve the beneficial effects of the method of message transmission in the random process provided by any one of the first aspect to the fifth aspect.

In a twentieth aspect, the embodiment of the present application provides a computer program product comprising instructions, when the computer program product is run on a network device, causing the network device to perform the random in-process message provided by the sixth aspect or the seventh aspect. The method of transmission can also achieve the beneficial effects of the method of message transmission in the random process provided by the second aspect.

DRAWINGS

1 is a schematic structural diagram of a communication system provided by an embodiment of the present application;

2 is a schematic flowchart of a method for message transmission in a random access process according to an embodiment of the present application;

3 is a schematic structural diagram of a message sent by a network device to a terminal device in a random access process;

4 is a schematic diagram of message transmission of random access;

FIG. 5 is a schematic flowchart of a method for message transmission in a random access process according to an embodiment of the present application;

6 is another schematic flowchart of a method for message transmission in a random access process according to an embodiment of the present application;

FIG. 7 is another schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application;

FIG. 8 is another schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of a communication apparatus according to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of a terminal device according to an embodiment of the present application;

11 is a schematic structural diagram of a network device according to an embodiment of the present application;

FIG. 12 is another schematic structural diagram of a terminal device according to an embodiment of the present application;

FIG. 13 is another schematic structural diagram of a network device according to an embodiment of the present application.

detailed description

The technical solutions in the present application will be clearly and completely described below in conjunction with the drawings in the present application.

The method for message transmission in the random access process provided by the embodiment of the present application may be applicable to a long term evaluation (LTE) system, or other wireless communication systems using various radio access technologies, for example, using code division multiple access ( Code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single A system of access technologies such as single carrier-frequency division multiple access (SC-FDMA). The method for message transmission in the random access process provided by the embodiment of the present application is also applicable to other wireless communication systems, such as a subsequent evolution system, such as the fifth generation wireless (5th generation, 5G, also known as New Radio (NR)). System (or NR system), etc., no restrictions here. Further, the embodiment of the present application can also be specifically applied to a communication system in the NB-IoT, and an enhanced machine type communication (eMTC) system. FIG. 1 is a schematic structural diagram of a communication system provided by an embodiment of the present application. The communication system provided by the embodiment of the present application includes, but is not limited to, a network device and a terminal device (for example, the terminal device 1 to the terminal device 6), which is not limited herein. The network device and the terminal device shown in FIG. 1 may be referred to as a communication device, and the network device and the terminal device may each be a chip or a plurality of chips working together, and the network device and/or the terminal device may further include The network device and/or the input device coupled to the terminal device are used to perform the method for message transmission in the random access process provided by the embodiment of the present application. It can be determined according to the actual application scenario, and no limitation is imposed here. The network device and the terminal device provided by the embodiments of the present application may perform data or signaling transmission, including uplink transmission and downlink transmission. It can be understood here that the uplink transmission may be that the terminal device sends data or signaling to the network device, and the downlink transmission may be that the network device sends data or signaling to the terminal device.

The terminal device involved in the present application may be a device that provides voice and/or data connectivity to a user, including a wired terminal and a wireless terminal. The wireless terminal may be a handheld device having a wireless connection function, or another processing device connected to the wireless modem, and a mobile terminal that communicates with one or more core networks via a radio access network (RAN). For example, the wireless terminal can be a mobile phone, a computer, a tablet, a personal digital assistant (PDA), a mobile internet device (MID), a wearable device, and an e-book reader. Wait. As another example, the wireless terminal can be a gas station, a printer, an electric meter, a watch, a water dispenser, and the like. As another example, the wireless terminal can also be a portable, pocket, handheld, computer built-in or in-vehicle mobile device. For another example, the wireless terminal can be a mobile station, an access point, or the like. The specific representation of the wireless terminal may be determined according to the actual application scenario of the NB-IOT, and is not limited herein. User equipment (UE) is a type of terminal equipment and is a name in the LTE system. For convenience of description, in the following description of the present application, the above-mentioned device will be described by taking a terminal device as an example. The network device involved in the embodiment of the present application is a communication device deployed in a radio access network for providing a wireless communication function for a terminal device. The network device may include various forms of macro base stations, micro base stations, relay stations, access point base station controllers, transmission and reception nodes (TRPs), and the like. In a system using different radio access technologies, the specific name of the network device may be different. For example, in an LTE network, a network device (or a base station) is called an evolved node B (eNB), and is followed by In the evolution system, it can also be called a new radio node B (new radio node B, gNB). For convenience of description, in the subsequent description of the present application, the above-mentioned devices are collectively referred to as network devices.

In the 3GPP protocol R13 or R14, the terminal device needs to complete the random access first, and establish a radio resource control (RRC) link with the network device before the uplink service data can be transmitted, due to random access and RRC. There are many interactive signalings during the establishment of the link, and the power consumption of the terminal device is high. Especially for NB-IoT-based terminal devices, the resulting delay and power consumption are more obvious.

Referring to FIG. 2, FIG. 2 is a schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application. The random access procedure performed before the terminal device accesses the network can be referred to the following steps S101 to S104.

S101. The terminal device sends a message 1 to the network device.

In some feasible implementation manners, the message 1 may also be referred to as an Msg1 (Message 1) message, and the message 1 may specifically be a preamble. When the terminal device sends the preamble sequence, the resource may be randomly selected to send the preamble sequence. If multiple terminal devices send the same preamble sequence on the same resource, a collision may occur. If multiple terminal devices send different preamble sequences on the same resource and the sequences are orthogonal, no collision will occur.

S102. The network device sends a message 2 to the terminal device.

In some feasible implementation manners, after the message 1 sent by the terminal device to the network device, if the network device detects the preamble sequence on a certain time-frequency resource, the network device carries the preamble sequence in message 2 (Msg2), indicating that the network The device detected the preamble sequence. At the same time, the network device also carries a random access response (RAR) in message 2. How many RARs are carried in the message 2, how many preamble sequences are detected by the network device on the time-frequency resource.

Illustratively, the structure of the message 2 is described below with reference to FIG. 3. FIG. 3 is a schematic structural diagram of a message sent by the network device to the terminal device in the random access process. As shown in FIG. 3, the message 2 includes a media access control (MAC) frame header and a random access response. In addition to this, message 2 may also include padding. The MAC header includes a number of MAC subheaders, and the MAC header includes a backoff identifier and a random access preamble identifier.

When the network device detects n (n is an integer greater than or equal to 1) preamble sequence, the MAC frame header in message 2 includes n random access preamble identifiers (RAPIDs), message 2 The random access response in the middle includes n random access responses (MAC RAR1, MAC RAR2...MAC RARn).

Exemplarily, the random access response specifically includes: a timing advanced command, an uplink grant (UL grant), a temporary (Cell Radio Network Temporary Identifier, C-RNTI), and Reserved bits (remembered as R).

In some feasible implementation manners, the uplink grant information (UL grant) included in the message 2 is used to indicate a transport block size (TBS) that is allowed to be used in the message 3.

S103. The terminal device sends a message 3 to the network device.

In some feasible implementation manners, after receiving the message 2, the terminal device checks whether the message 2 carries the preamble sequence that it previously sent to the network device. If the preamble sequence sent by the terminal device is not included in the message 2, the random access is considered to be unsuccessful, and the terminal device needs to perform step 101 to resend the message 1 again. If the message 2 includes the preamble sequence sent by the terminal device, the terminal device sends the message 3 according to the time-frequency resource indicated by the uplink grant (UL grant) in the random access response corresponding to the preamble sequence. When transmitting the message, the terminal device carries the cell radio network temporary identifier (C-RNTI) of the terminal device or the terminal device identifier from the core network in the message 3. Therefore, the message 3 carries the unique identifier of the terminal device and is used to identify the current terminal device that requests access.

S104. The network device sends a message 4 to the terminal device.

After the network device detects the message 3, it will send a message 4 to the terminal device, and in the message 4, specify which terminal device wins in the conflict resolution. Among them, the above message 3 and message 4 are mainly used to solve the conflict problem.

The above steps S101 to S104 show a complete random access procedure.

In the random access procedure shown in the foregoing steps S101 and S104, the terminal device sends a message 1 to the network device, and requests the network device to allocate an uplink grant (UL Grant) through the message 1 to transmit the uplink service in the message 3. data. If the network device has sufficient resources, the terminal device is assigned a larger uplink grant and is sent to the terminal device through message 2. The terminal device sends a message 3 to the network device and carries the uplink service data in the message 3. After receiving the message 3, the network device may send a message 4 to the terminal device, where the contention resolution and the end indication are carried in the message 4. After receiving the message 4, the terminal device can feed back an acknowledgement (ACK) to the network device. Through the random access process, the terminal device completes the transmission of the uplink service data, and the terminal device does not need to enter the connection state, and can quickly enter the idle state to save power consumption of the terminal device.

In the random access procedure shown in the above steps S101 to S104, the network device cannot know exactly what the application layer service data that the terminal device needs to transmit. Therefore, for data transmission during random access, the network device can only allocate a fixed maximum size of transport block (TB) (ie, maximum TBS). If the maximum TBS is much larger than the TB size required for the terminal device to transmit the application layer service data, the terminal device needs to perform a large proportion of packet padding at the MAC layer, which makes the transmission efficiency of the uplink transmission low.

For example, the terminal device may only need to send 400 bits of uplink service data (including application layer service data, packet header overhead of each layer, etc.). However, since the network device does not know the actual amount of data that the terminal device needs to send, the network device is The TBS allocated by the terminal device to send message 3 is 1000 bits. The terminal device receives the message 2 from the network device, and determines, by using the indication of the uplink grant in the RAR corresponding to the terminal device in the message 2, that the TBS allocated by the network device is 1000 bits, and then the terminal device fills when sending the message 3 ( The ratio of padding is actually (1000-400) / 1000 = 60%. The Ratio is too high, that is, most of the actually transmitted bits are padded bits, which greatly wastes power consumption of uplink resources and terminal devices.

In order to reduce power consumption of the terminal device and reduce waste of uplink resources, the terminal device may be allowed to select a TBS that is smaller than the TBS allocated by the network device to perform uplink service data transmission. For example, if the terminal device only needs 400 bits of uplink service data to be transmitted, the terminal device can independently select 500 bits (the TBS can be a TBS that the terminal device actually needs to use, and for convenience of description, it can be assumed that TBS1) to send the message 3. Instead of using 1000 bits of TBS (assumed to be TBS2) to send. At this time, the network device needs to demodulate and decode the message 3 according to different TBS assumptions (according to the assumption of TBS1 and the assumption of TBS2, respectively). If the network device can correctly demodulate the decoded message 3, the TBS size of the message 3 can be determined, and the content of the application layer service data carried by the message 3 can be obtained at the same time. However, such uplink service data transmission methods still have problems.

For example, as shown in FIG. 4 and FIG. 4, FIG. 4 is a schematic diagram of message transmission of random access. After the terminal device sends the message 3 to the network device, the network device may not correctly demodulate and decode the narrowband physics of the message 3, whether under the assumption of TBS1 or under the assumption of TBS2, when the message 3 is sent for the first time. Narrowband physical downlink shared channel (NPDSCH). At this point, the network device cannot get the correct TBS for message 3 (eg, TBS1). In order to continue to obtain the content in the message 3, the network device may use the Narrowband Physical Downlink Control Channel (NPDCCH) to schedule retransmission of the message 3. However, at this time, since the actual TBS size of the message 3 is not known, the network device can only retransmit the message 3 according to the resource required by the TBS2 (assumed to be 1000 bits, including the remaining resources except the message 3), so that the message 3 The retransmission brings a very large waste of uplink resources.

In the NB-IoT, the network device scheduling terminal device performs retransmission (ie, retransmission) of the message 3 by using the NPDCCH, specifically, scheduling by using downlink control information (DCI) format N0. For the definition of each domain of the above DCI format N0, refer to section 6.4.3.1 of 3GPP TS36.212 as follows:

The terminal device can interpret the 'resource assignment' field in the DCI format N0, and obtain the index of the resource unit (RU) by interpreting the 'Resource assignment' field (index, which can be recorded as _IRU for convenience description). The index of the MCS (index, which can be recorded as I _MCS for convenience of description) is obtained by interpreting the 'modulation and coding scheme (MCS)' field in the DCI format N0. The terminal device can determine the index of the TBS (referred to as I _TBS ) according to the I _MCS , and further determine the TBS according to (I _TBS , I _RU ) and Table 1. Table 1 is a transport block size (TBS) lookup table for NPDCCH (ie, Table 16.5.1.2-2 in 3GPP TS 36.212: Transport block size (TBS) table for NPUSCH), see 16.5 in 3GPP TS 36.213. Section 1.2, no restrictions here.

Table 1

However, when data is transmitted during the random access procedure, the combination of the newly defined TBS and _IRU cannot be queried in Table 1 above. For example, suppose that the TBS used in the initial transmission of message 3 is 776 bits, and the corresponding I _RU is 6. When message 3 is retransmitted, the scheduling information is indicated by DCI format N0, and DCI format N0 can only indicate the one defined in Table 1 above. The combination of _TBS , I _RU ), for a TBS with an I _RU of 6, cannot find a suitable I _TBS such that the determined TBS is 776 bits. When the message 3 is retransmitted, the DCI sent by the network device to the terminal device cannot directly indicate the combination of the TBS and the _IRU used in the initial transmission of the message 3. Therefore, the TBS used for retransmitting the message 3 cannot be determined, and the operation is inconvenient and the applicability is poor. .

The embodiment of the present application provides a method and a device for message transmission in a random access procedure, which can redefine the 'modulation and coding scheme' field in the DCI format N0, and can pass the 'modulation in the DCI format N0 when the message 3 is retransmitted. The and coding scheme' field is re-interpreted, so that the TBS used for retransmission of the message 3 can be determined by the scheduling information corresponding to the 'modulation and coding scheme' field, and the operation is simple and the applicability is strong.

Embodiment 1:

Referring to FIG. 5, FIG. 5 is a schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application. The method provided by the embodiment of the present application may include the following steps:

S201. The terminal device receives downlink control information from the network device.

In some possible implementation manners, the various domains included in the foregoing downlink control information may be referred to the DCIformat N0. As shown in the above DCI format N0, the DCI sent by the network device to the terminal device may include a modulation and coding scheme field (ie, a 'modulation and coding scheme' field), and part of the bits of the modulation and coding scheme field are used to indicate that the retransmission of the scheduled transmission message is allowed. The TBS used.

In some feasible implementation manners, when the network device does not correctly demodulate and decode the message 3 of the first transmission (also referred to as initial transmission) of the terminal device, the retransmission of the NPDCCH scheduling message 3 may be used. Optionally, the network device may send a DCI to the terminal device, and schedule retransmission of the message 3 (also referred to as retransmission) through the DCI format N0. The terminal device can interpret the 'modulation and coding scheme' field in the DCI format N0, and determine the TBS allowed to be used by the retransmission message 3 by interpreting the state corresponding to the partial bits in the 'modulation and coding scheme' field. Here, the used TBS can be described by taking the first TBS as an example. Optionally, for the scheduling message of other domains in the DCI format N0, the terminal device can be interpreted by using the implementation manner specified in the 6.4.3.1 section of the protocol 3GPP TS 36.212, which is not limited herein.

Optionally, in the DCI sent by the network device to the terminal device, the allowed TBS indicated by the partial bits of the modulation and coding scheme field may be a TBS in the candidate TBS set, and the TBS is the first TBS, which is convenient. Description, the TBS can be described as a designated TBS (for example, Ti). The candidate TBS set may include one or more candidate TBSs including the specified TBS.

Optionally, the terminal device may determine the candidate TBS set of the retransmission message 3 by using any one of the following group composition mode 1 to the group composition mode 2.

The composition of the collection is one:

Optionally, the foregoing candidate TBS set may be determined by a maximum TBS broadcast by the network device. The terminal device may obtain the maximum TBS allowed for the retransmission message 3 from the system message broadcasted by the network device, and determine the candidate TBS set according to the maximum TBS.

In some feasible implementation manners, the size (in bits) of the maximum TBS broadcast by the network device through the system message may be {1000, 936, 808, 680, 584, 504, 408, 328}. The size of the maximum TBS is different, and the number of optional TBSs corresponding to the size of the optional TBS is also different, as shown in Table 2 below. Table 2 is a schematic diagram of the value of TBS. As shown in the following Table 2, if the maximum TBS broadcasted by the network device through the system message is 1000 bits, the terminal device retransmits the message 3 using four optional TBSs, respectively TBS1 (marked as T1 for convenience of description), TBS2 (which can be labeled as T2 for convenience of description), TBS3 (which can be labeled as T3 for convenience of description), and TBS4 (which can be labeled as T4 for convenience of description). As shown in Table 2 below, the above values of T1, T2, T3 and T4 are 328, 536, 776 and 1000, respectively. At this time, T1, T2, T3, and T4 can be combined to obtain a candidate TBS set, and T1, T2, T3, and T4 are all candidate TBSs.

Table 2

	328	408	504	584	680	808	936	1000
T1	328	328	328	328	328	328	328	328
T2		408	408	408	456	504	504	536
T3			504	504	584	680	712	776
T4				584	680	808	936	1000

Optionally, the foregoing Table 2 may be configured by a network device, or may be specified by a communication protocol, and is not limited herein.

Optionally, if the maximum TBS of the network device broadcasted by the system message is 504 bits, the terminal device retransmits the message 3 by using three optional TBSs, which can be respectively labeled as T1, T2, and T3, where the T1 and T2 are respectively The values of T3 and T3 are 328, 408 and 504, respectively. At this time, T1, T2, and T3 may be combined to obtain a candidate TBS set, and T1, T2, and T3 are all candidate TBSs in the candidate TBS set.

The network device may indicate that one of the candidate TBS sets is a designated TBS by using a partial bit in the above-mentioned 'modulation and coding scheme' field, and indicates the designated TBS as a TBS allowed to be used by the retransmission message 3. Similarly, when the maximum TBS of the network device broadcasted by the system message is 936 bits, 808 bits, 680 bits, 584 bits, 408 bits, or 328 bits, the terminal device can determine the number of optional TBSs and the size of each TBS through the foregoing Table 2, and then The determined one or more TBSs are combined into a candidate TBS set, and the size of each TBS in the candidate TBS set is less than or equal to the value of the maximum TBS of the system message broadcast, and is not limited herein.

Collection composition two:

Optionally, the set of candidate TBSs allowed by the foregoing terminal device retransmission message 3 may be determined by the maximum TBS and the preset number of TBSs broadcast by the network device. The number of the preset TBSs may be configured by the network device, or may be specified by the communication protocol. For convenience of description, the preset number of TBSs may also be described as an example, and is not limited herein.

In some feasible implementation manners, the terminal device may determine one or more optional TBSs corresponding to the largest TBS broadcasted by the network device system message according to the foregoing set composition manner, and then determine the determined one or more optional TBSs. Compose a candidate TBS set. For convenience of description, the first candidate TBS set may be used as an example for description. In addition, optionally, for each cell, if there are multiple optional TBSs of the terminal device retransmission message 3 corresponding to the maximum TBS broadcasted by the system message by the network device, some of the plurality of selectable TBSs may be combined. Candidate TBS set. For convenience of description, the second candidate TBS set may be taken as an example. At this time, the second candidate TBS set is a candidate TBS set allowed for the terminal device to retransmit the message 3.

For each cell, among the plurality of candidate TBSs constituting the first candidate TBS set and/or the second candidate TBS set, each candidate TBS may compose the candidate TBS set according to the value from small to large, that is, at the first Ti<Ti+1 in the candidate TBS set and/or the second candidate TBS set. For example, in the first candidate TBS set {T1, T2, T3, and T4} (corresponding to {328, 536, 776, 1000}), the value of T1 (328) is smaller than the value of T2 (536), and the value of T2 is taken. The value (536) is less than the value of T3 (776).

Optionally, the network device configurable terminal device selects a TBS component message of the preset TBS number (one or more) from the first candidate TBS set (that is, multiple selectable TBSs corresponding to the maximum TBS broadcasted by the system message). 3 Retransmission of the candidate TBS set that is allowed to be used.

For example, when the network device passes the optional TBS corresponding to the largest TBS broadcasted by the system message (that is, the TBS that the terminal device actually allows to transmit), there are four, for example, {T1, T2, T3, T4}, and the preset TBS is configured. The number is 4, and the terminal device can form the four candidate TBSs of the above {T1, T2, T3, T4} into the second candidate TBS set. When the second candidate TBS set is {T1, T2, T3, T4}, the terminal device may select the candidate TBS as the TBS used for retransmission of the message 3 by using the following method (for the convenience of description, the TBS may be specified as an example). Description).

Method 1: T2 or T4;

The terminal device may select T2 or T4 as the designated TBS from the second candidate TBS set {T1, T2, T3, T4}.

Method 2: T1 or T2 or T3 or T4;

The terminal device may select T1, or T2, or T3, or T4 as the designated TBS from the second candidate TBS set {T1, T2, T3, T4}.

There are four optional TBSs corresponding to the maximum TBS broadcasted by the network device through the system message (that is, the TBS actually allowed to be transmitted by the terminal device), for example, {T1, T2, T3, T4}, and the preset TBS number is configured as 3. The terminal device may form three candidate TBSs of the above {T1, T2, T3, T4}, for example, {T1, T2, T3} into a second candidate TBS set. When the second candidate TBS set is {T1, T2, T3}, the terminal device may select the candidate TBS as the designated TBS used for the retransmission of the message 3 in the following manner.

Method 1: T2 or T3;

The terminal device may select T2 or T3 as the designated TBS from the second candidate TBS set {T1, T2, T3}.

Method 2: T1 or T2 or T3;

The terminal device may select T1, or T2, or T3 as the designated TBS from the second candidate TBS set {T1, T2, T3}.

There are 4 optional TBSs corresponding to the maximum TBS broadcast by the network device through the system message (that is, the TBS actually allowed to be transmitted by the terminal device) (for example, {T1, T2, T3, T4}, or 3 (for example, {T1, T2, T3}, for convenience of description, taking 4 as an example), and configuring the preset number of TBSs to be 2, the terminal device may select 2 candidate TBSs of the above {T1, T2, T3, T4}, for example, {T1, T2} constitutes a second candidate TBS set. When the second candidate TBS set is {T1, T2}, the terminal device can select T1 or T2 as the designated TBS used for message 3 retransmission.

In some feasible implementation manners, the network device may indicate, by using a part of the bits in the 'modulation and coding scheme' field, the candidate TBS set (including the first candidate TBS set determined by the foregoing set composition mode 1 and/or the above set composition) One of the second candidate TBS sets determined by mode 2 (for example, T1) is a designated TBS.

Optionally, the specified TBS that is allowed to be used by the network device to indicate that the terminal device retransmits the message 3 through the partial bits in the 'modulation and coding scheme' field may be implemented by using the following indication mode 1 or the indication mode 2:

Direction 1:

Optionally, the eight states corresponding to the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI sent by the network device to the terminal device may be used to indicate the designated TBS allowed by the terminal device to retransmit the message. ). Optionally, the eight states may also indicate, by the terminal device, whether the retransmission message 3 allows the candidate TBS that is less than or equal to Ti to perform message transmission.

Optionally, when there are four optional TBSs corresponding to the maximum TBS broadcast by the network device through the system message, the optional TBS indicated by the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI The range is {T ₁ , T ₂ , T ₃ , T ₄ }, and the indication of the designated TBS can be performed in the form of Table 3 as follows, and whether the terminal device retransmission message 3 allows the message to be used by the candidate TBS less than or equal to Ti. Instructions sent. Table 3 is an indication table of the designated TBS that the terminal device retransmits the message 3 to use. Correspondingly, the 'Modulation and coding scheme' field in DCI is 4 bits (4 bits). The correspondence between the state corresponding to the 4 bits and the designated TBS and whether the permission is allowed is configured by the network device, or is defined by a communication protocol, and is not limited herein.

table 3

I MCS (status)	TBS(Ti)	Whether to allow
0	T 1	Yes
1	T 2	Yes
2	T 3	Yes
3	T 4	Yes
4	T 1	no
5	T 2	no
6	T 3	no
7	T 4	no
8	Reserved (reserved)	Reserved
9	Reserved	Reserved
10	Reserved	Reserved
11	Reserved	Reserved
12	Reserved	Reserved
13	Reserved	Reserved
14	Reserved	Reserved
15	Reserved	Reserved

As shown in the above table 3, when the state corresponding to the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 0, the terminal device may be instructed to retransmit the designated TBS allowed by the message 3 to be T1. And the terminal device is allowed to retransmit the message 3 to use the candidate TBS smaller than T1 for message transmission. At this time, the terminal device may select the T1 retransmission message 3, and may also retransmit the message 3 using other candidate TBSs smaller than T1. Optionally, if there is no candidate TBS that is smaller than T1 in the candidate TBS, the T1 retransmission message 3 is selected, which may be determined according to the actual application scenario, and is not limited herein. When the status of the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 4, the terminal device may be instructed to retransmit the specified TBS that is allowed to be used by the message 3 to be T1, and the terminal device is not allowed to retransmit. Message 3 uses a candidate TBS less than T1 for message transmission. At this time, the terminal device selects the T1 retransmission message 3, and does not allow the candidate TBS smaller than T1 in the candidate TBS set to perform the message 3 retransmission, which will not be described below.

Optionally, when there are three optional TBSs corresponding to the maximum TBS broadcast by the network device through the system message, the optional TBS indicated by the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI The range is {T ₁ , T ₂ , T ₃ }, and the indication of the designated TBS can be performed in the form of Table 4 as follows, and whether the terminal device retransmission message 3 allows the use of the candidate TBS less than or equal to Ti for the message transmission. . Table 4 is another indication diagram of the designated TBS that the terminal device retransmits the message 3 to use. Similarly, the 'Modulation and coding scheme' field in DCI is 4 bits (4 bits).

Table 4

I MCS (status)	TBS(Ti)	Whether to allow
0	T 1	Yes
1	T 2	Yes
2	T 3	Yes
3	Reserved	Reserved
4	T 1	no
5	T 2	no
6	T 3	no
7	Reserved	Reserved
8	Reserved		Reserved
9	Reserved	Reserved
10	Reserved	Reserved
11	Reserved	Reserved
12	Reserved	Reserved
13	Reserved	Reserved
14	Reserved	Reserved
15	Reserved	Reserved

As shown in the above Table 4, when the state corresponding to the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 0, the terminal device may be instructed to retransmit the designated TBS allowed by the message 3 to be T1. And the terminal device is allowed to retransmit the message 3 to use the candidate TBS smaller than T1 for message transmission. At this time, the terminal device may select the T1 retransmission message 3, and may also retransmit the message 3 using other candidate TBSs smaller than T1. Optionally, if there is no candidate TBS that is smaller than T1 in the candidate TBS, the T1 retransmission message 3 is selected, which may be determined according to the actual application scenario, and is not limited herein. When the state corresponding to the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 4, the terminal device may be instructed to retransmit the specified TBS allowed by the message 3 to be T1, and the terminal device is not allowed to retransmit. Message 3 uses a candidate TBS less than T1 for message transmission. At this time, the terminal device selects the T1 retransmission message 3, and does not allow the candidate TBS smaller than T1 in the candidate TBS set to perform the message 3 retransmission, which will not be described below.

Optionally, when there are two optional TBSs corresponding to the maximum TBS broadcast by the network device through the system message, the optional TBS indicated by the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI The range is {T ₁ , T ₂ }, and the indication of the designated TBS can be performed in the form of Table 5 as follows, and whether the terminal device retransmission message 3 allows the use of the candidate TBS less than or equal to Ti to transmit the message. Table 5 is another indication diagram of the designated TBS allowed by the terminal device retransmission message 3.

table 5

I MCS (status)	TBS(Ti)	Whether to allow
0	T 1	Yes
1	T 2	Yes
2	Reserved	Reserved
3	Reserved	Reserved
4	T 1	no
5	T 2	no
6	Reserved	Reserved
7	Reserved	Reserved
8	Reserved		Reserved
9	Reserved	Reserved
10	Reserved	Reserved
11	Reserved	Reserved
12	Reserved	Reserved
13	Reserved	Reserved
14	Reserved	Reserved
15	Reserved	Reserved

As shown in the above Table 5, when the state corresponding to the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 0, the terminal device may be instructed to retransmit the designated TBS allowed by the message 3 to be T1. And the terminal device is allowed to retransmit the message 3 to use the candidate TBS smaller than T1 for message transmission. At this time, the terminal device may select the T1 retransmission message 3, and may also retransmit the message 3 using other candidate TBSs smaller than T1. Optionally, if there is no candidate TBS that is smaller than T1 in the candidate TBS, the T1 retransmission message 3 is selected, which may be determined according to the actual application scenario, and is not limited herein. When the status of the partial bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 5, the terminal device may be instructed to retransmit the specified TBS to be used by the message 3 to be T2, and the terminal device is not allowed to retransmit. Message 3 uses a candidate TBS less than T2 for message transmission. At this time, the terminal device selects the T2 retransmission message 3, and does not allow the candidate TBS smaller than T2 in the candidate TBS set to perform the message 3 retransmission, which will not be described below.

Direction 2:

Optionally, the 2 bits of the 'Modulation and coding scheme' field (I _MCS ) in the DCI sent by the network device to the terminal device indicate that the designated TBS is in the candidate TBS set (eg, {T1, T2, T3, T4}) One, the indication is as shown in the last column on the right side of Table 6. Table 6 is another indication diagram of the specified TBS (Ti) allowed for the terminal device retransmission message 3. Optionally, 1 bit of the 'Modulation and coding scheme' field (I _MCS ) in the DCI is used to indicate whether the terminal device retransmission message 3 allows to use a candidate TBS less than or equal to Ti for message transmission, and the available bit '0' and '1' is allowed or not allowed. It can be determined according to the actual application scenario. There is no restriction here.

Table 6

	328	408	504	584	680	808	936	1000	TBS indication
T1	328	328	328	328	328	328	328	328	00
T2		408	408	408	456	504	504	536	01
T3			504	504	584	680	712	776	10
T4				584	680	808	936	1000	11

As shown in Table 6 above, when the TBS indication of 2 bits is 00, the designated TBS corresponding to the indication is T1. When the TBS indication of 2 bits is 11, the designated TBS corresponding to the indication is T4. The correspondence between the TBS indication and the designated TBS may be configured by the network device, or may be specified by a communication protocol, and is not limited herein.

Optionally, the foregoing field (2 bits) for indicating a specified TBS, and a field (1 bit) for indicating whether the terminal device retransmission message 3 is allowed to use a candidate TBS less than or equal to Ti for message transmission is in a “Modulation and coding”. The scheme' field can be located at the upper 3 bits, or at the lower 3 bits, or it can occupy 3 bits separately. It can be determined according to the actual application scenario, and no limitation is imposed here.

S202. The terminal device determines the target TBS according to the first TBS.

In some feasible implementation manners, after receiving the DCI sent by the network device, the terminal device may interpret the 'Modulation and coding scheme' field in the DCI, and determine a retransmission message by using some bits in the 'Modulation and coding scheme' field. The designated TBS (i.e., the first TBS) that is allowed to be used, and the target TBS used by the retransmission message 3 can be determined according to the indication of the partial TBS and/or the partial bits in the above-mentioned 'Modulation and coding scheme' field. The foregoing target TBS is a TBS that the terminal device actually needs to use to resend the message 3 to the network device.

Optionally, when the specified TBS indicated by the partial bits in the above-mentioned 'Modulation and coding scheme' field may be one of the first candidate TBS set and/or the second candidate TBS set, after the terminal device determines the specified TBS, Then the designated TBS is determined as the target TBS. The terminal device retransmits the message 3 using the target TBS, and after receiving the message 3, the network device does not need to perform TBS blind detection. That is, at this time, the blind detection TBS set of the network device blindly detecting the message 3 is empty.

Optionally, when the specified TBS indicated by the partial bits in the above-mentioned 'Modulation and coding scheme' field may be one of the first candidate TBS set and/or the second candidate TBS set, and the 'Modulation and coding scheme' domain The partial bit indicates that when the candidate TBS less than or equal to the designated TBS is allowed to perform retransmission of the scheduled transmission message, the terminal device may select one candidate TBS less than or equal to the designated TBS from the candidate TBS set, and determine the selected candidate TBS as the target. TBS. The terminal device retransmits the message 3 using the target TBS. At this time, the network device does not know the size of the TBS actually used by the terminal device. Therefore, after receiving the message 3, the network device needs to perform TBS blind detection. The network device performs the TBS blind detection when receiving the TBS retransmitted by the terminal device. At this time, the TBS range of the blind detection of the network device (that is, the blind detection TBS set, which will not be described below) is the candidate TBS set corresponding to the maximum TBS of the system message broadcast. A set of candidate TBSs smaller than the specified TBS (eg, the first candidate TBS set). The TBS used by the terminal device to retransmit the message 3 may be the same as the TBS used in the initial message 3, and is not limited herein.

For example, if the maximum TBS broadcasted by the network device through the system message is 1000 bits, the number of preset TBSs allowed by the terminal device configured by the network device is 4, that is, the candidate TBS set is {328, 536, 776, 1000}. The terminal device may determine one candidate TBS from the above-mentioned candidate TBS set to perform retransmission of the message 3. The network device performs TBS blind detection based on the assumptions of the four TBSs, that is, the blind detection TBS set of the network device blindly detecting the message 3 is {328, 536, 776, 1000}. Assume that the TBS selected by the terminal device initial message 3 is 328 bits, and the specified TBS allowed to be used by the retransmission message 3 according to the partial bits in the 'Modulation and coding scheme' field (I _MCS ) in the DCI is 536 bits, and according to The partial bits of the 'Modulation and coding scheme' field (I _MCS ) determine that when the message 3 is retransmitted, the TBS that is smaller than the specified TBS (536 bits) is allowed to perform the message transmission, and the terminal device can retransmit the message 3 from {328,536}. The target TBS of the retransmission message 3 is determined, and the message 3 is sent to the network device based on the target TBS. The message 3 of the network device receiving the retransmission of the terminal device is blind detection based on the two TBS assumptions of {328, 536} to demodulate and decode the message 3.

Optionally, the specified TBS indicated by the partial bits in the 'Modulation and coding scheme' field may be one of the candidate TBS sets, and the partial bits in the 'Modulation and coding scheme' field indicate that the use is less than or equal to When the candidate TBS of the designated TBS performs retransmission of the scheduled transmission message, after the terminal device determines the specified TBS, the designated TBS is determined as the target TBS. The terminal device retransmits the message 3 using the target TBS, and after receiving the message 3, the network device does not need to perform TBS blind detection.

Optionally, if the specified TBS indicated by the part of the bits in the 'Modulation and coding scheme' field may be one of the candidate TBS sets, and the size of the designated TBS is greater than the TBS actually required by the terminal device, the terminal device according to actual needs The used TBS performs retransmission of message 3. After receiving the message 3, the network device performs TBS blind detection to demodulate and decode the message 3. If the size of the designated TBS is smaller than the TBS actually required by the terminal device, the terminal device determines the target TBS used by the retransmission message 3 according to the following manner. The TBS that the terminal device actually needs to adopt is a TBS determined by the terminal device according to the size of the uplink service data that it needs to upload. For example, when the uplink service data that the terminal device actually needs to upload is 400 bits, the TBS that the terminal device actually needs to use may be 500 bits.

Manner 1: The TBS of the specified size of the communication protocol is determined as the target TBS.

Optionally, the terminal device may perform retransmission of the message 3 according to the 88 bits described in the section 16.3.3 of the protocol 3GPP TS 36.213, that is, the terminal device may determine the 88 bits specified by the protocol as the target TBS of the message 3 retransmission. When the network device receives the retransmission message 3, in addition to performing TBS blind detection according to up to 4 types of TBSs (for example, {328, 536, 776, 1000}), it is also necessary to blindly detect 88 bits.

Manner 2: The first TBS is determined as the target TBS.

Optionally, the terminal device may fill the 88 bits of the protocol described in section 16.3.3 of the 3GPP TS 36.213 to the same size as the designated TBS (ie, the first TBS), and perform retransmission of the message 3 according to the designated TBS. That is, the terminal device may fill the 88 bits specified by the protocol to the same size as the designated TBS, and determine the TBS padded to the same size as the designated TBS as the target TBS of the message 3 retransmission.

Optionally, in some feasible implementation manners, if the size of the designated TBS indicated by the DCI sent by the network device is smaller than the TBS actually required by the terminal device, the terminal device may re-initiate random access or wait for random access competition. After the timeout expires, the random access is re-initiated, and the uplink service data is transmitted in the message 3 of the re-initiated random access procedure. Alternatively, the terminal device may re-initiate the random access, or wait for the random access competition resolution timing to timeout to re-initiate the random access, and transmit the uplink service data after the re-initiated random access procedure message 3. For example, if the TBS actually needs to be used by the terminal device is 500 bits, and the specified TBS indicated by the DCI transmitted when the network device scheduling message 3 is retransmitted is 400 bits, the terminal device may not use the scheduling of the network device, and the contention resolution (or The contention is resolved. A new random access attempt is made after the timeout expires, so that the uplink service data can be transmitted in the re-initiated random access procedure. Here, the random access attempt may select an existing random access resource or a random access resource indicating an EDT, and no limitation is imposed herein.

S203. The terminal device resends the scheduled transmission message of the random access to the network device according to the target TBS.

In some feasible implementation manners, the foregoing scheduling transmission message may be the message 3 carrying the uplink service data in the random access process, or may be sent by the terminal device to the network device in the random access procedure specified in the 3GPP protocol R13 or R14. Message 3 (88bits), no restrictions here. After the terminal device determines the target TBS, the message 3 can be resent to the network device. The resent message 3 carries the uplink service data transmitted according to the target TBS.

In the embodiment of the present application, the scheduling information of the first (first) transmission of the random access scheduled transmission message is indicated by the uplink grant in the RAR. The scheduling information of the retransmission of the random access scheduled transmission message is indicated by the DCI, and is indicated by the DCI format N0 in the NB-IoT. In the eMTC, it is indicated by DCI format 6-0A or DCI format 6-0B.

In the embodiment of the present application, the TBS used by the terminal device to retransmit the message 3 to the network device may be determined according to the TBS indicated by the partial bit of the modulation and coding scheme field in the DCI, and the method for determining the TBS used by the retransmission message 3 is increased. Sex, the implementation of the terminal device retransmission message 3 is more flexible. At the same time, the terminal device can determine the TBS of the retransmission message 3 directly from the partial bits of the modulation coding scheme field in the DCI, and determine the TBS of the retransmission message 3 based on the TBS, so as to prevent the network device from performing the retransmission message 3 on the TBS. The unnecessary blind detection can improve the efficiency and reliability of data transmission during the random access process, and the applicability is stronger.

Embodiment 2:

In the first embodiment, part of the bits of the modulation and coding scheme field in the DCI transmitted by the network device to the terminal device may directly indicate that the terminal device retransmits the TBS allowed to be used by the message 3, and/or indicates whether the terminal device retransmits the message 3 It is allowed to use a certain TBS that is smaller than the TBS allowed by the above DCI for message transmission. In addition, the partial bits of the modulation and coding scheme field in the DCI that can be sent by the network device to the terminal device in the embodiment of the present application can directly indicate whether the terminal device retransmits the message 3 to allow other TBSs smaller than the allowed TBS to be used. The message transmission is performed without indicating the TBS that is allowed to be used, and the diversity of the selection manner of the TBS used by the terminal device to retransmit the message 3 is increased, and the bits occupying the modulation and coding scheme domain are also saved, thereby saving resources.

Referring to FIG. 6, FIG. 6 is another schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application. The method provided by the embodiment of the present application may include the following steps:

S301. The terminal device receives a system message broadcast by the network device, and determines, according to the received system message, a maximum TBS that is allowed to be used.

In some feasible implementation manners, the size (in bits) of the maximum TBS broadcast by the network device through the system message may be {1000, 936, 808, 680, 584, 504, 408, 328}. The size of the maximum TBS is different, and the number of the optional TBSs is different from the size of the optional TBS. For details, refer to Table 2 above. The terminal device can receive the system message broadcasted by the network device, and the maximum TBS query table 2 broadcasted by the system message, so that the optional TBS corresponding to the largest TBS can be determined. As shown in Table 2, if the maximum TBS broadcast by the network device through the system message is 1000 bits, the terminal device retransmits the message 3 using four optional TBSs, which are respectively T1, T2, T3, and T4. As shown in Table 2, the above values of T1, T2, T3 and T4 are 328, 536, 776 and 1000, respectively. At this time, the above T1, T2, T3 and T4 may be candidate TBSs for the terminal device to retransmit the message 3.

S302. The terminal device receives downlink control information from the network device.

In some implementations, the implementation manner of the terminal device receiving the DCI from the network device may be referred to the implementation manner provided in step S101 in the foregoing Embodiment 1, and details are not described herein again.

Optionally, the DCI may include a modulation coding scheme field, where a part of the bits of the modulation coding scheme field is used to indicate whether to allow retransmission of the message 3 by using a candidate TBS that is less than or equal to the maximum TBS broadcast by the network device system message. The terminal device can reinterpret the 'Modulation and coding scheme' field (I _MCS ) in DCI format N0 when message 3 is retransmitted. The 1 bit in the 'Modulation and coding scheme' field (I _MCS ) can be used to indicate whether the terminal device is allowed to transmit using the largest TBS less than the system message broadcast when the message 3 is retransmitted. Optionally, for the scheduling message of other domains in the DCI format N0, the terminal device can be interpreted by using the implementation manner specified in the 6.4.3.1 section of the protocol 3GPP TS 36.212, which is not limited herein.

S303. The terminal device determines the target TBS according to the indication of the maximum TBS and the partial bits of the modulation and coding scheme field.

S304. The terminal device resends the scheduled transmission message of the random access to the network device according to the target TBS.

Optionally, in some feasible implementation manners, if the terminal device receives a bit from the network device, the 1 bit in the 'Modulation and coding scheme' field (I _MCS ) indicates that the terminal device is not allowed to use less than when retransmitting the message 3 The TBS indicated by the DCI (ie, the maximum TBS broadcasted by the system message), and the terminal device interprets the indication from the DCI to transmit the maximum TBS of the system message broadcast when retransmitting the message 3. The network device does not perform TBS blind detection when receiving the message 3 retransmitted by the terminal device, which can reduce the waste of resources for blind detection of the network device and improve the efficiency of data transmission during the random access process.

If the 1 bit in the 'Modulation and coding scheme' field (I _MCS ) in the DCI received by the terminal device from the network device indicates that the terminal device is allowed to use the TBS smaller than the DCI indicated when retransmitting the message 3, the terminal device is retransmitting At message 3, a candidate TBS may be determined to retransmit the message 3 in the candidate TBS set corresponding to the largest TBS broadcasted by the system message, for example, {T1, T2, T3, T4}. At this time, the candidate TBS selected by the terminal device from the candidate TBS set may be less than or equal to the maximum TBS broadcast by the system message. The network device performs TBS blind detection when receiving the message 3 retransmitted by the terminal device, and the TBS range of the network device blind detection is the candidate TBS set {T1, T2, T3, T4}. At this time, the terminal device determines that the TBS used in the retransmission message 3 is the same as the TBS used to determine the initial transmission message 3, and details are not described herein again.

For example, the maximum TBS broadcasted in the system message of the network device is 1000 bits, and the number of preset TBSs of the TBS allowed by the terminal device retransmission message 3 configured by the network device is 4, that is, the candidate TBS set is {328, 536, 776. , 1000}. The terminal device may determine one candidate TBS as the target TBS from the candidate TBS set, and resend the message 3 to the network device according to the target TBS. The network device performs blind detection based on the four TBS hypotheses in the candidate TBS set described above. It is assumed that the TBS selected by the terminal device initial message 3 is 328 bits. When the terminal device determines, according to the 1 bit in the 'Modulation and coding scheme' field (I _MCS ) in the DCI sent by the network device, the message is not allowed when retransmitting the message 3. When the TBS is smaller than the DCI indicated by the DCI (or the retransmission DCI), the terminal device may select the TBS that is the same as the maximum TBS broadcasted by the system message (ie, 1000 bits) when retransmitting the message 3, and re-establish the network device based on the maximum TBS. Send message 3. The network device does not perform TBS blind detection when receiving the message 3 retransmitted by the terminal device. When the terminal device determines, according to the 1 bit of the 'Modulation and coding scheme' field (I _MCS ) in the DCI sent by the network device, that the TBS indicated by the DCI is allowed to be used when retransmitting the message 3, the terminal device retransmits the message 3 The target TBS used by the retransmission message 3 can be determined from the candidate TBS set {328, 536, 776, 1000} described above, and the message 3 is retransmitted to the network device according to the target TBS. When the network device receives the message 3, it performs blind detection based on four assumptions in the candidate TBS set {328, 536, 776, 1000}.

In the embodiment of the present application, the network device can quickly adjust the value of 1 bit of the 'Modulation and coding scheme' field (I _MCS ) in the DCI sent to the terminal device according to the load condition, and the value of the 1 bit is used to make the value of the 1 bit. The TBS blind detection when the message 3 of the retransmission of the terminal device can be enabled or disabled can reduce the waste of message reception, thereby improving the efficiency and reliability of data transmission during the random access process, and the applicability is stronger. The TBS used by the terminal device to retransmit the message 3 to the network device may determine the TBS based on the 2-bit indication of the modulation and coding scheme field in the DCI, and increase the diversity of the TBS adopted by the retransmission message 3 to achieve more flexibility.

Embodiment 3:

Referring to FIG. 7, FIG. 7 is another schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application. The method provided by the embodiment of the present application may include the following steps:

S401. The terminal device receives downlink control information from the network device.

In some possible implementations, the network device does not need to modify the scheduling information of the modulation and coding scheme domain in the DCI sent to the terminal device. The terminal device may receive the DCI for scheduling message 3 retransmission from the network device, and interpret the scheduling information of each domain in the DCI by using an implementation manner as specified in 6.4.3.1 of the protocol 3GPP TS 36.212. The scheduling information of the modulation and coding scheme field in the DCI may be used to indicate that the terminal device retransmits the TBS allowed by the message 3. The terminal device may interpret the modulation code according to the implementation manner specified in the 6.4.3.1 section of the protocol 3GPP TS36.212. The scheduling information of the solution domain determines the allowed TBS indicated by the network device.

In some possible implementations, the network device does not need to modify the scheduling information of the modulation and coding scheme domain in the DCI sent to the terminal device. The terminal device may receive the DCI for scheduling message 3 retransmission from the network device, and interpret the scheduling information of each domain in the DCI by using an implementation manner as specified in 6.4.3.1 of the protocol 3GPP TS 36.212. The scheduling information of the modulation and coding scheme field in the DCI may be used to instruct the terminal device to resend the second TBS of the message 3. The terminal device selects a candidate TBS that is closest to the second TBS value from the candidate TBS set according to the second TBS, or selects a candidate TBS that is closest to the second TBS value and larger than the second TBS, or a candidate from the candidate TBS set. A candidate TBS that is closest to the second TBS value and smaller than the second TBS is selected in the TBS set. The selected candidate TBS is taken as the first TBS. For example, the terminal device can interpret the 'resource assignment' field in the DCI format N0, and obtain the index of the resource unit (RU) by interpreting the 'Resource assignment' field (index, which can be recorded as _IRU for convenience description) The index of the MCS (index, which can be recorded as I _MCS for convenience of description) is obtained by interpreting the 'modulation and coding scheme (MCS)' field in DCI format N0. The terminal device may determine an index of the TBS (referred to as I _TBS ) according to the I _MCS , and then determine the second TBS according to (I _TBS , I _RU ) and Table 1. Table 1 is a transport block size (TBS) lookup table for NPDCCH (ie, Table 16.5.1.2-2 in 3GPP TS 36.212: Transport block size (TBS) table for NPUSCH), see 16.5 in 3GPP TS 36.213. Section 1.2, no restrictions here. The terminal device selects a candidate TBS that is closest to the second TBS value from the candidate TBS set according to the second TBS, or selects a candidate TBS that is closest to the second TBS value and larger than the second TBS, or a candidate from the candidate TBS set. A candidate TBS that is closest to the second TBS value and smaller than the second TBS is selected in the TBS set. The selected candidate TBS is taken as the first TBS. It can be determined according to the actual application scenario, and no limitation is imposed here.

S402. The terminal device determines the target TBS according to the first TBS.

S403. The terminal device resends the scheduling transmission message to the network device according to the target TBS.

Optionally, in some feasible implementation manners, if the TBS (ie, the first TBS) allowed by the retransmission message 3 indicated by the DCI received by the terminal device from the network device is greater than or equal to the TBS actually needed by the terminal device, The terminal device can determine the TBS actually needed to be used as the target TBS. The terminal device resends the message 3 to the network device based on the TBS actually needed. After receiving the message 3, the network device performs TBS blind detection to demodulate and decode the content in the message 3.

Optionally, in some feasible implementation manners, if the TBS allowed by the retransmission message 3 indicated by the DCI received by the terminal device from the network device is smaller than the TBS actually required by the terminal device, the terminal device is as follows: Mode 2 determines the target TBS used by the retransmission message 3. The TBS that the terminal device actually needs to adopt is a TBS determined by the terminal device according to the size of the uplink service data that it needs to upload. For example, when the uplink service data that the terminal device actually needs to upload is 400 bits, the TBS that the terminal device actually needs to use may be 500 bits.

Manner 1: The TBS of the specified size of the communication protocol is determined as the target TBS.

Optionally, the terminal device may perform retransmission of the message 3 according to the 88 bits described in the section 16.3.3 of the protocol 3GPP TS 36.213, that is, the terminal device may determine the 88 bits specified by the protocol as the target TBS of the message 3 retransmission. When the network device receives the retransmission message 3, in addition to blind detection by up to 4 types of TBSs (for example, {328, 536, 776, 1000}), it is also necessary to blindly detect 88 bits.

Manner 2: The first TBS is determined as the target TBS, and the target TBS is padded to the same size as the designated TBS.

Optionally, the terminal device may fill the 88 bits of the protocol described in section 16.3.3 of the 3GPP TS 36.213 to the same size as the designated TBS (ie, the first TBS), and perform retransmission of the message 3 according to the designated TBS. That is, the terminal device may fill the 88 bits specified by the protocol to the same size as the designated TBS, and determine the TBS padded to the same size as the designated TBS as the target TBS of the message 3 retransmission.

Optionally, in some feasible implementation manners, if the size of the designated TBS indicated by the DCI sent by the network device is smaller than the TBS actually required by the terminal device, the terminal device may re-initiate random access or wait for random access competition. After the timeout expires, the random access is re-initiated, and the uplink service data is transmitted in the message 3 of the re-initiated random access procedure. Alternatively, the terminal device may re-initiate the random access, or wait for the random access competition resolution timing to timeout to re-initiate the random access, and transmit the uplink service data after the re-initiated random access procedure message 3. For example, if the TBS actually needs to be used by the terminal device is 500 bits, and the specified TBS indicated by the DCI transmitted when the network device scheduling message 3 is retransmitted is 400 bits, the terminal device may not use the scheduling of the network device, and the contention resolution (or The contention is resolved. A new random access attempt is made after the timeout expires, so that the uplink service data can be transmitted in the re-initiated random access procedure. Here, the random access attempt may select an existing random access resource or a random access resource indicating an EDT, and no limitation is imposed herein.

In the embodiment of the present application, the network device does not need to adjust the value of each bit of the 'Modulation and coding scheme' field (I _MCS ), and the implementation complexity is low. The terminal device may determine the TBS that is allowed to be used according to the scheduling information of each domain in the DCI, and determine the target TBS for retransmitting the message 3 according to the TBS that is actually needed, and increase the TBS used by the terminal device to retransmit the message 3. The flexibility of the selection method also saves the bits occupying the modulation coding scheme domain and saves resources.

Embodiment 4:

In the above embodiments, the modulation and coding scheme field in the DCI transmitted by the network device to the terminal device may indicate that the terminal device retransmits the TBS allowed to be used by the message 3. The terminal device may interpret the DCI and determine the permission according to the indication of the DCI. The TBS used. In addition, in the embodiment of the present application, the terminal device may not interpret the scheduling information of the modulation and coding scheme domain in the DCI when interpreting the DCI, thereby saving the signaling overhead of transmitting data in the random access process, and improving the random connection. The efficiency and reliability of data transmission during the process is more applicable.

Referring to FIG. 8, FIG. 8 is another schematic flowchart of a method for message transmission in a random access procedure according to an embodiment of the present application. The method provided by the embodiment of the present application may include the following steps:

S501. The terminal device receives downlink control information from the network device.

S502. The terminal device interprets each domain except the modulation and coding scheme field in the downlink control information before resending the scheduled transmission message.

S503. The terminal device resends the scheduling transmission message to the network device according to the intercepted scheduling information of each domain and the target TBS.

The foregoing scheduled transmission message is the message 3. The message 3 carries the uplink service data transmitted according to the target TBS, and the target TBS is the TBS used by the terminal device to send the message 3 to the network device for the first time.

Optionally, in some feasible implementation manners, the 'Modulation and coding scheme' field (I _MCS ) in the DCI format N0 is not limited when the message 3 is retransmitted. When the network device transmits the DCI retransmitted by the scheduling message 3, the 'Modulation and coding scheme' field (I _MCS ) can be filled with a fixed value or arbitrarily indicated a value. The terminal device does not interpret the 'Modulation and coding scheme' field (I _MCS ) in the DCI when receiving the DCI, and ensures that the TBS used in the retransmission of the message 3 is the same as the TBS used in the initial transmission. The terminal device can interpret each domain except the 'Modulation and coding scheme' field (I _MCS ) in the DCI according to the protocol, and can obtain the scheduling information of each domain according to the interpretation and the initial transmission of the message 3 The TBS resends message 3 to the network device. The network device can blindly detect the retransmission message 3 by using the same TBS assumption that the message 3 was originally transmitted.

For example, the maximum TBS broadcast by the network device through the system message is 1000 bits, and the number of preset TBSs allowed by the terminal device resending message 3 configured by the network device is 4, that is, the candidate TBS set is {328, 536, 776, 1000. }. The terminal device may determine a candidate TBS from the candidate TBS set to perform retransmission of the message 3. The network device performs blind detection of four TBS hypotheses based on candidate TBSs included in the candidate TBS set. It is assumed that the TBS selected by the terminal device initial message 3 is 328 bits, and the terminal device does not interpret the 'Modulation and coding scheme' field (I _MCS ) in the DCI that receives the retransmission of the scheduling message 3. The interpretation of the scheduling information of other domains in the DCI can be interpreted in the manner specified by the protocol, and is not limited herein. The terminal device uses the same TBS as the initial transmission when retransmitting the message 3. The network device performs blind detection based on the four TBS hypotheses of {328, 536, 776, 1000} in the candidate TBS set to obtain the content contained in the message 3.

In the embodiment of the present application, the terminal device may not interpret the scheduling information of the modulation and coding scheme domain in the DCI when interpreting the DCI, thereby saving signaling overhead of transmitting data in the random access process, and improving random access. The efficiency and reliability of data transmission during the process is more applicable.

Referring to FIG. 9, FIG. 9 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application. As shown in FIG. 9, the communication device 90 provided by the embodiment of the present application includes a processor 901, a memory 902, a transceiver 903, and a bus system 904.

The processor 901, the memory 902 and the transceiver 903 are connected by a bus system 904.

The above memory 902 is used to store programs. In particular, the program can include program code, the program code including computer operating instructions. The memory 902 includes, but is not limited to, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read only memory (EPROM), or Portable disc read-only memory (CD-ROM). Only one memory is shown in Fig. 9, and of course, the memory can be set to a plurality as needed. The memory 902 may also be a memory in the processor 901, which is not limited herein.

The memory 902 stores the following elements, executable modules or data structures, or a subset thereof, or an extended set thereof:

Operation instructions: include various operation instructions for implementing various operations.

Operating system: Includes a variety of system programs for implementing various basic services and handling hardware-based tasks.

The processor 901 controls the operation of the communication device 90. The processor 901 may be one or more central processing units (CPUs). In the case that the processor 901 is a CPU, the CPU may be a single-core CPU. It can also be a multi-core CPU.

In a specific application, the various components of the communication device 90 are coupled together by a bus system 904, which may include, in addition to the data bus, a power bus, a control bus, a status signal bus, and the like. However, for clarity of description, various buses are labeled as bus system 904 in FIG. For ease of representation, only the schematic drawing is shown in FIG.

Any of the methods of the terminal device disclosed in the foregoing embodiments of the present application, or the method of the terminal device disclosed in the foregoing embodiments; or any one of the foregoing FIG. 5 to FIG. 8 provided by the embodiment of the present application, or each of the foregoing The method of the network device of the embodiment may be applied to the processor 901 and the transceiver 903, or may be implemented by the processor 901 and the transceiver 903. The processor 901 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the foregoing method may be completed by an integrated logic circuit of hardware in the processor 901 or an instruction in a form of software. The processor 901 may be a general-purpose processor, a digital signal processing (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or Other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by the hardware decoding processor, or may be performed by a combination of hardware and software modules in the decoding processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory 902, and the processor 901 and the transceiver 903 can read the information in the memory 902, perform any one of FIG. 5 to FIG. 8 in combination with the hardware thereof, or the method steps of the terminal device described in the above embodiments. Or performing the method steps of any one of FIG. 5 to FIG. 8 or the network device described in the above embodiments in combination with its hardware.

Referring to FIG. 10, FIG. 10 is a schematic structural diagram of a terminal device according to an embodiment of the present application. As shown in FIG. 10, the terminal device provided by the embodiment of the present application includes a function module such as a processor 101, a memory 102, a user interface 103, a communication interface 104, a coupler 105, and an antenna 106. The memory 102 described above may correspond to the memory 902 of the communication device 90 shown in FIG. The above memory 102 is used to store programs. In particular, the program can include program code, the program code including computer operating instructions. The memory 102 includes, but is not limited to, a RAM, a ROM, an EPROM, or a CD-ROM, etc., and is not limited herein. In addition, the foregoing memory 102 may also be a memory in the processor 101, which is not limited herein.

The memory 102 stores the following elements, executable modules or data structures, or subsets thereof, or their extended sets:

Operation instructions: include various operation instructions for implementing various operations.

Operating system: Includes a variety of system programs for implementing various basic services and handling hardware-based tasks.

The processor 101 described above controls the operation of the terminal device, and the processor 101 may be one or more CPUs. The method of any one of FIG. 5 to FIG. 8 provided by the embodiment of the present application, or the terminal device disclosed in the foregoing embodiments may be applied to the processor 101 or implemented by the processor 101. Processor 101 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method may be completed by an integrated logic circuit of hardware in the processor 101 or an instruction in a form of software. The processor 101 described above may be a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by the hardware decoding processor, or may be performed by a combination of hardware and software modules in the decoding processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory 102, and the processor 101 reads the information in the memory 102, and performs any one of FIG. 5 to FIG. 8 in conjunction with its hardware, or the method steps of the terminal device described in the above embodiments.

The user interface 103 of the terminal device is mainly used for providing an input interface for the user, and acquiring data input by the user. The user interface 103 may include a multimedia input and/or output device 1031, a camera 1032, a display 1033, and the like, which are not limited herein. The user interface 103 may be an information input and/or output module that interacts with a user of the terminal device, such as a microphone and/or a speaker of a terminal device such as a mobile phone, a front and/or rear camera, and a touch screen, etc. Make restrictions. Optionally, the user interface 103 may also include a standard wired interface, a wireless interface, and the like, which are not limited herein.

The processor 101 of the terminal device can be coupled to an input device such as the antenna 106 through one or more communication interfaces 104 and couplers 105, and perform any one of FIG. 5 to FIG. 8 in combination with other functional modules, or as described in the above embodiments. For the implementation of the terminal device, refer to the implementation manners provided in the foregoing embodiments, which are not limited herein. "Coupled" herein means that two components are bonded directly or indirectly to each other. This combination may be fixed or movable, which may allow for the transfer of fluid, electrical, electrical or other types of signals between the two components.

Referring to FIG. 11, FIG. 11 is a schematic structural diagram of a network device according to an embodiment of the present application. As shown in FIG. 11, the network device provided by the embodiment of the present application includes a processor 1101, a memory 1102, a transmitter 1103, a receiver 1104, a network interface 1107, and the like. The functional modules such as the processor 1101, the transmitter 1103, and the receiver 1104 can be coupled to an input device such as the antenna 1106 through the coupler 1105. The processor 1101 can perform any of the implementations of the network device described in the foregoing embodiments, or the implementation manners provided by the network devices described in the foregoing embodiments. This is not a limitation. "Coupled" herein means that two components are bonded directly or indirectly to each other. This combination may be fixed or movable, which may allow for the transfer of fluid, electrical, electrical or other types of signals between the two components.

The memory 1102 can correspond to the memory 902 of the communication device 90 shown in FIG. The above memory 1102 is used to store programs. In particular, the program can include program code, the program code including computer operating instructions. The memory 1102 includes, but is not limited to, a RAM, a ROM, an EPROM, or a CD-ROM, etc., and is not limited herein. In addition, the foregoing memory 1102 may also be a memory in the processor 1101, which is not limited herein.

Memory 1102 stores the following elements, executable modules or data structures, or a subset thereof, or their extended set:

Operation instructions: include various operation instructions for implementing various operations.

Operating system: Includes a variety of system programs for implementing various basic services and handling hardware-based tasks.

The processor 1101 described above controls the operation of the network device, and the processor 1101 may be one or more CPUs. The method of any one of FIG. 5 to FIG. 8 provided by the embodiment of the present application, or the network device disclosed in the foregoing embodiments may be applied to the processor 1101 or implemented by the processor 1101. The processor 1101 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the foregoing method may be completed by an integrated logic circuit of hardware in the processor 1101 or an instruction in a form of software. The processor 1101 described above may be a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by the hardware decoding processor, or may be performed by a combination of hardware and software modules in the decoding processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory 1102, and the processor 1101 reads the information in the memory 1102, and performs any one of FIG. 5 to FIG. 8 in conjunction with its hardware, or the method steps of the network device described in the above embodiments. The network interface 1107 may optionally include a standard wired interface, a wireless interface (such as a WI-FI interface), and the like, and is not limited herein.

Referring to FIG. 12, FIG. 12 is another schematic structural diagram of a terminal device according to an embodiment of the present application. As shown in FIG. 12, the terminal device provided by the embodiment of the present application includes: a receiving unit 121, a processing unit 122, and a sending unit 123.

The receiving unit 121 is configured to receive downlink control information from the network device, where the downlink control information includes a modulation and coding scheme field, where the first part of the modulation and coding scheme field is used to indicate that the first transmission of the scheduled transmission message of the random access is retransmitted The block size TBS, the first TBS is a TBS in the candidate TBS set.

The processing unit 122 is configured to determine a target TBS according to the foregoing first TBS.

The sending unit 123 is configured to resend the random access scheduled transmission message to the network device according to the target TBS determined by the processing unit 122.

In some possible implementations, the processing unit 122 is configured to determine the first TBS as the target TBS.

In some feasible implementation manners, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message for performing the random access by using the candidate TBS that is less than or equal to the first TBS is allowed to be performed;

The processing unit 122 is configured to:

Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.

In some feasible implementation manners, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed to be used;

The processing unit 122 is configured to determine the first TBS as the target TBS.

In some feasible implementations, the foregoing modulation and coding scheme domain further includes a second partial bit;

The second part of the bit is used to indicate that retransmission of the scheduled transmission message for performing the random access by using the candidate TBS that is less than or equal to the first TBS is allowed to be used;

The processing unit 122 is configured to:

Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.

In some feasible implementations, the foregoing modulation and coding scheme domain further includes a second partial bit;

The second part of the bit is used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed to be used;

The processing unit 122 is configured to determine the first TBS as the target TBS.

In some possible implementations, the processing unit 122 is configured to:

When the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used is determined as the target TBS.

In some possible implementations, the processing unit 122 is configured to:

When the first TBS is smaller than the TBS actually required to be used, the TBS of the communication protocol specified size is determined as the target TBS.

In some possible implementations, the processing unit 122 is configured to:

When the first TBS is smaller than the TBS actually needed to be used, the first TBS is determined as the target TBS.

In a specific implementation, the terminal device can perform the implementation manners performed by the terminal device in any of the embodiments shown in FIG. 5 to FIG. 8 by using the built-in units. For details, refer to the steps provided in the foregoing steps of the foregoing embodiments. Method to realize. Therefore, the beneficial effects (or advantages) of the implementations provided in the respective steps of the above various embodiments can be achieved, and details are not described herein.

Referring to FIG. 13, FIG. 13 is another schematic structural diagram of a network device according to an embodiment of the present application. As shown in FIG. 13, the terminal device provided by the embodiment of the present application includes: a sending unit 131 and a receiving processing unit 132.

The sending unit 131 is configured to send, to the terminal device, the downlink control information, where the downlink control information includes a modulation and coding scheme field, where the first part of the modulation and coding scheme field is used to indicate that the first TBS of the scheduled transmission message of the random access is retransmitted. The first TBS is one TBS in the candidate TBS set.

The receiving processing unit 132 is configured to receive, according to the foregoing first TBS, the scheduled transmission message of the random access that is resent by the terminal device.

In some possible implementation manners, the receiving processing unit 132 is configured to: perform receiving processing on the scheduled transmission message of the random access according to the foregoing first TBS.

In some feasible implementation manners, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message for performing the random access by using the candidate TBS that is less than or equal to the first TBS is allowed to be performed;

The above receiving processing unit 132 is configured to:

Determining, by the one or more candidate TBSs in the candidate TBS set that are less than or equal to the first TBS, as a blind detection TBS set of the scheduled transmission message, and performing the scheduled transmission message of the random access according to the one or more candidate TBSs. Receive processing.

In some feasible implementation manners, the foregoing first part of the foregoing modulation and coding scheme field is further used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed to be used;

The receiving processing unit 132 is configured to: perform receiving processing on the scheduled transmission message of the random access according to the first TBS.

In some feasible implementations, the foregoing modulation and coding scheme domain further includes a second partial bit;

The second part of the bit is used to indicate that retransmission of the scheduled transmission message for performing the random access by using the candidate TBS that is less than or equal to the first TBS is allowed to be used;

The above receiving processing unit 132 is configured to:

Determining, by the one or more candidate TBSs in the candidate TBS set that are less than or equal to the first TBS, as a blind detection TBS set of the scheduled transmission message, and performing the scheduled transmission message of the random access according to the one or more candidate TBSs. Receive processing.

In some feasible implementations, the foregoing modulation and coding scheme domain further includes a second partial bit;

The second part of the bit is used to indicate that the retransmission of the scheduled transmission message is not allowed to be performed by using the candidate TBS that is less than or equal to the first TBS;

The receiving processing unit 132 is configured to: perform receiving processing on the scheduled transmission message of the random access according to the first TBS.

In a specific implementation, the network device may perform the implementation performed by the network device in any of the embodiments shown in FIG. 5 to FIG. 8 by using the built-in units. For details, refer to the steps in the foregoing various embodiments. The way to achieve it. Therefore, the beneficial effects (or advantages) of the implementations provided in the respective steps of the above various embodiments can be achieved, and details are not described herein.

The embodiment of the present application provides a computer readable storage medium, where the instructions are stored in the computer readable storage medium, and when the instruction is run on the terminal device, causing the terminal device to perform any one of the foregoing FIG. 5 to FIG. For the implementation manners of the terminal device described in the foregoing embodiments, refer to the implementation manners provided in the foregoing embodiments, and details are not described herein again.

An embodiment of the present application provides a computer readable storage medium, where the instructions are stored in a computer readable storage medium, and when the instruction is run on a network device, causing the network device to perform any one of the foregoing FIG. 5 to FIG. For the implementation manners of the network devices described in the foregoing embodiments, refer to the implementation manners provided in the foregoing embodiments, and details are not described herein again.

The embodiment of the present application further provides a computer program product comprising instructions, when the computer program product is run on the terminal device, causing the terminal device to perform any one of the foregoing FIG. 5 to FIG. 8 or described in the above embodiments. The implementation of the terminal device.

The embodiment of the present application further provides a computer program product comprising instructions, when the computer program product is run on a network device, causing the network device to perform any one of the foregoing FIG. 5 to FIG. 8 or described in the foregoing embodiments. The implementation of the network device.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims (30)

1. A method for message transmission in a random access process, comprising:

   And receiving, by the network device, the downlink control information, where the downlink control information includes a modulation and coding scheme field, where a first part of the modulation coding scheme field is used to indicate that the first transport block size TBS of the scheduled transmission message of the random access is retransmitted, The first TBS is one TBS in the candidate TBS set;

   Determining a target TBS according to the first TBS;

   And transmitting, according to the target TBS, the scheduled transmission message of the random access to the network device.
2. The method according to claim 1, wherein the determining the target TBS according to the first TBS comprises:

   The first TBS is determined as a target TBS.
3. The method according to claim 1, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that scheduling of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Resending the transmitted message;

   Determining the target TBS according to the first TBS includes:

   Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.
4. The method according to claim 1, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is not allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Scheduling the retransmission of the transmitted message;

   Determining the target TBS according to the first TBS includes:

   The first TBS is determined as a target TBS.
5. The method of claim 1, wherein the modulation and coding scheme domain further comprises a second partial bit;

   The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS;

   Determining the target TBS according to the first TBS includes:

   Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.
6. The method of claim 1, wherein the modulation and coding scheme domain further comprises a second partial bit;

   The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed to be used;

   Determining the target TBS according to the first TBS includes:

   The first TBS is determined as a target TBS.
7. The method according to claim 1, wherein the determining the target TBS according to the first TBS comprises:

   When the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used is determined as the target TBS.
8. The method according to claim 1, wherein the determining the target TBS according to the first TBS comprises:

   When the first TBS is smaller than the TBS actually required to be used, the TBS specified by the communication protocol is determined as the target TBS.
9. The method according to claim 1, wherein the determining the target TBS according to the first TBS comprises:

   When the first TBS is smaller than the TBS actually needed to be used, the first TBS is determined as the target TBS.
10. A method for message transmission in a random access process, comprising:

    Transmitting, to the terminal device, the downlink control information, where the downlink control information includes a modulation and coding scheme field, where the first part of the modulation coding scheme field is used to indicate that the first transport block size TBS of the scheduled transmission message of the random access is retransmitted, The first TBS is one TBS in the candidate TBS set;

    Receiving, according to the first TBS, the scheduled transmission message of the random access retransmitted by the terminal device.
11. The method according to claim 10, wherein the receiving, according to the first TBS, the scheduled transmission message of the random access retransmitted by the terminal device comprises:

    Receiving, by the first TBS, the scheduled transmission message of the random access.
12. The method according to claim 10, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that scheduling of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Resending the transmitted message;

    The receiving, according to the first TBS, the scheduled transmission message that is retransmitted by the terminal device, includes:

    Determining, in the candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a blind detection TBS set of scheduling transmission messages, and performing the random access according to the one or more candidate TBSs The transmission message is scheduled for reception processing.
13. The method according to claim 10, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is not allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Scheduling the retransmission of the transmitted message;

    The receiving, according to the first TBS, the scheduled transmission message that is retransmitted by the terminal device, includes:

    Receiving, by the first TBS, the scheduled transmission message of the random access.
14. The method of claim 10, wherein the modulation and coding scheme domain further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS;

    The receiving, according to the first TBS, the scheduled transmission message that is retransmitted by the terminal device, includes:

    Determining, in the candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a blind detection TBS set of scheduling transmission messages, and performing the random access according to the one or more candidate TBSs The transmission message is scheduled for reception processing.
15. The method of claim 10, wherein the modulation and coding scheme domain further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of a scheduled transmission message by using a candidate TBS that is less than or equal to the first TBS is not allowed;

    The receiving, according to the first TBS, the scheduled transmission message that is retransmitted by the terminal device, includes:

    Receiving, by the first TBS, the scheduled transmission message of the random access.
16. A terminal device, comprising:

    a receiving unit, configured to receive downlink control information from a network device, where the downlink control information includes a modulation and coding scheme field, where a first part of the modulation coding scheme field is used to indicate that the first of the scheduled transmission messages of the random access is retransmitted a transport block size TBS, the first TBS being one of the candidate TBS sets;

    a processing unit, configured to determine a target TBS according to the first TBS;

    And a sending unit, configured to resend the scheduled transmission message of the random access to the network device according to the target TBS determined by the processing unit.
17. The terminal device according to claim 16, wherein the processing unit is configured to:

    The first TBS is determined as a target TBS.
18. The terminal device according to claim 16, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Scheduling the retransmission of the transmitted message;

    The processing unit is used to:

    Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.
19. The terminal device according to claim 16, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is not allowed to be performed by using a candidate TBS that is less than or equal to the first TBS. Resending the scheduled transmission of the message;

    The processing unit is used to:

    The first TBS is determined as a target TBS.
20. The terminal device according to claim 16, wherein the modulation and coding scheme field further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS;

    The processing unit is used to:

    Selecting one candidate TBS that is less than or equal to the first TBS from the candidate TBS set, and determining the selected candidate TBS as the target TBS.
21. The terminal device according to claim 16, wherein the modulation and coding scheme field further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access by using the candidate TBS that is less than or equal to the first TBS is not allowed to be used;

    The processing unit is used to:

    The first TBS is determined as a target TBS.
22. The terminal device according to claim 16, wherein the processing unit is configured to:

    When the first TBS is greater than or equal to the TBS actually needed to be used, the TBS actually needed to be used is determined as the target TBS.
23. The terminal device according to claim 16, wherein the processing unit is configured to:

    When the first TBS is smaller than the TBS actually required to be used, the TBS specified by the communication protocol is determined as the target TBS.
24. The terminal device according to claim 16, wherein the processing unit is configured to:

    When the first TBS is smaller than the TBS actually needed to be used, the first TBS is determined as the target TBS.
25. A network device, comprising:

    a sending unit, configured to send downlink control information to the terminal device, where the downlink control information includes a modulation and coding scheme field, where a first part of the modulation coding scheme field is used to indicate that the first transmission of the random access scheduling transmission message is a transport block size TBS, the first TBS being one of the candidate TBS sets;

    a receiving processing unit, configured to receive, according to the first TBS, the scheduled transmission message of the random access retransmitted by the terminal device.
26. The network device according to claim 25, wherein the receiving processing unit is configured to:

    Receiving, by the first TBS, the scheduled transmission message of the random access.
27. The network device according to claim 25, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS. Scheduling the retransmission of the transmitted message;

    The receiving processing unit is configured to:

    Determining, in the candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a blind detection TBS set of scheduling transmission messages, and performing the random access according to the one or more candidate TBSs The transmission message is scheduled for reception processing.
28. The network device according to claim 25, wherein the first partial bit of the modulation and coding scheme field is further used to indicate that the random access is not allowed to be performed by using a candidate TBS that is less than or equal to the first TBS. Resending the scheduled transmission of the message;

    The receiving processing unit is configured to:

    Receiving, by the first TBS, the scheduled transmission message of the random access.
29. The network device according to claim 25, wherein said modulation and coding scheme field further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of the scheduled transmission message of the random access is allowed to be performed using a candidate TBS that is less than or equal to the first TBS;

    The receiving processing unit is configured to:

    Determining, in the candidate TBS set, one or more candidate TBSs that are less than or equal to the first TBS as a blind detection TBS set of scheduling transmission messages, and performing the random access according to the one or more candidate TBSs The transmission message is scheduled for reception processing.
30. The network device according to claim 25, wherein said modulation and coding scheme field further comprises a second partial bit;

    The second partial bit is used to indicate that retransmission of a scheduled transmission message by using a candidate TBS that is less than or equal to the first TBS is not allowed;

    The receiving processing unit is configured to:

    Receiving, by the first TBS, the scheduled transmission message of the random access.

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