CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a national stage of International Application No. PCT/CN2018/112260, filed on Oct. 27, 2018, which claims priority to Chinese Patent Application No. 201711148343.2, filed on Nov. 17, 2017. Each of these applications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the field of communications technologies, and in particular, to a communication method and a communications device.

BACKGROUND

In a long term evolution (LTE) system, data is transmitted between a base station and a terminal device based on a transport block (TB). Therefore, in the LTE system that supports a hybrid automatic repeat request (HARQ) technology, after receiving a data packet of a TB, a receiving device sends a response (for example, an acknowledgement/negative acknowledgement (ACK/NACK)) to a sending device to notify the sending device of a status of receiving (or decoding) the TB by the receiving device, so that the sending device determines, based on the receiving status of the TB, whether to retransmit the TB.

In the response, a payload of one bit may be used to indicate the receiving status of the TB. For example, when a value of the bit is 1 (that is, the response is a success response (for example, an ACK)), it indicates that the TB is received successfully; or when a value of the bit is 0 (that is, the response is a failure response (for example, a NACK)), it indicates that the TB fails to be received.

In the foregoing TB-based data transmission process, if a small part of the entire TB is received incorrectly, the entire TB is retransmitted. This wastes transmission resources. To resolve this problem, a data transmission technology based on a code block group (CBG) is introduced in a fifth-generation wireless access system—a new radio (NR) system. In the NR system, a TB to be sent by a sending device includes N CBGs. In this case, when some CBGs in the TB fail to be received due to a cause such as a poor channel status, the sending device retransmits only this part of CBGs that fail to be received. Compared with a TB-based data transmission technology, this technology can reduce retransmission overheads of the sending device, thereby saving transmission resources.

However, in a CBG-based data transmission process, when feeding back a response for the TB sent by the sending device each time, the receiving device needs to use a specified indication manner, to ensure that a payload in the feedback response can indicate a receiving status of the N CBGs (where N can be an integer greater than 2). According to the used indication manner, in a payload of different responses sent for a same TB, a bit in a same location indicates a receiving status of a CBG in a same location. A quantity of bits of a payload in a response affects both indication precision of the response and transmission resources of the response.

It can be learned from the foregoing descriptions that, in a communications system using the CBG-based data transmission technology, a single response indication manner has poor flexibility, and therefore the communications system cannot achieve a balance between improving indication precision of a response and reducing transmission resources of the response.

SUMMARY

This application provides a communication method and a communications device, to improve flexibility of a response indication manner.

According to a first aspect, an embodiment of this application provides a communication method. The method may be applied to a communications system that includes a terminal device and a network device. A first device is the terminal device or the network device that receives target data. A second device is the terminal device or the network device that sends the target data. In the method, indication manners of two responses (a first response and a second response) that are separately sent by the first device to the second device and that are used to indicate a transmission result of the target data are different.

According to the method, because indications of the two responses that are sent by the first device at different times and that are used to indicate transmission of the same target data may be different, this solution can improve flexibility of a response indication manner. Therefore, the communications system can flexibly adjust indication manners of responses sent at different times to ensure indication precision of the responses while reducing transmission resources of the responses.

In a possible implementation, before the first device sends the first response to the second device, the first device receives first data from the second device, where the first data is data in Xthtransmission of the target data, the first data includes some or all of the target data, the first response is used to indicate a transmission result of the target data after the Xthtransmission, and X is an integer greater than or equal to 1; and the first device generates the first response based on the transmission result of the target data after the Xthtransmission. Similarly, before the first device sends the second response to the second device, the first device receives second data from the second device, where the second data is data in Ythtransmission of the target data, the second data includes some or all of the target data, the second response is used to indicate a transmission result of the target data after the Ythtransmission, and Y is an integer greater than X; and the first device generates the first response based on the transmission result of the target data after the Xthtransmission.

According to the foregoing implementation, after each transmission of the target data, the first device may generate a corresponding response based on a transmission result of the target data after the transmission.

In a possible implementation, the response indication manner may include but is not limited to at least one of the following: a total data range indicated by the response, a quantity of indication bits included in the response, a quantity of first indication bits included in the indication bits of the response, a quantity of data blocks indicated by each first indication bit, a location of each data block indicated by each indication bit (including a first indication bit), whether locations of at least two data blocks indicated by each first indication bit are consecutive, or a logical operation method used for generating each first indication bit.

According to the foregoing implementation, the communications system may adjust the response indication manner from a plurality of perspectives, further improving flexibility of the response indication manner.

In a possible implementation, each response is used to indicate a transmission result of all of the target data, or indicate a transmission result of data transmitted each time. For example, when the second data includes some of the target data, the second response is used to indicate a transmission result of this part of data after the Y transmission.

According to the foregoing implementation, flexibility of a response in the communications system can be improved.

In a possible implementation, the first response includes PXindication bits, the PXindication bits are used to indicate a transmission result of the target data, the second response includes PYindication bits, the PYindication bits are used to indicate a transmission result of the target data, and both PXand PYare positive integers. In this case, that an indication manner of the first response is different from an indication manner of the second response includes at least the following several cases:

first case: PXand PYare unequal; and

second case: PXand PYare equal, and a k bit in the PXindication bits and a kthbit in the PYindication bits indicate transmission results of different parts of the target data, where k is a positive integer less than or equal to PX.

In a possible implementation, when the communications system transmits uplink data and downlink data by using a data-block-based data transmission technology, the target data includes N data blocks, where N is a positive integer. When each response is used to indicate all of the target data, the PXindication bits are used to indicate a transmission result of the N data blocks, where PXis less than or equal to N; and the PYindication bits are used to indicate a transmission result of the N data blocks, where PYis less than or equal to N.

In a possible implementation, the Piindication bits include Qifirst indication bits, any first indication bit is used to indicate a transmission result of at least two of the N data blocks, i is equal to X or Y, and Qiis a positive integer less than or equal to Pi.

In a possible implementation, each first indication bit in any response indicates at least two data blocks in consecutive locations; or each first indication bit in a response indicates at least two data blocks in nonconsecutive locations; or each of some indication bits in a response indicates at least two data blocks in consecutive locations, and each of another part of first indication bits indicates at least two data blocks in nonconsecutive locations.

According to this implementation, indication flexibility of a first indication bit in a response can be improved.

In a possible implementation, each of the Qifirst indication bits indicates a same quantity of data blocks; or

a quantity of data blocks indicated by at least one of the Qifirst indication bits is different from a quantity of data blocks indicated by another first indication bit.

According to this implementation, indication flexibility of a first indication bit in a response can be improved.

In a possible implementation, when N is an integer multiple of Ki, each of the Qifirst indication bits is used to indicate a transmission result of KiCBGs, Qi=N/Ki, and Kiis an integer greater than or equal to 2. For example, when N=9 and Ki=3, a corresponding response includes three first indication bits, and each first indication bit indicates a transmission result of three data blocks.

In a possible implementation, the Piindication bits include Pi−1 first indication bits and an indication bit used to indicate a transmission result of Lidata blocks, each of the Pi−1 first indication bits is used to indicate a transmission result of Kidata blocks, Pi=[N/Ki], Kiis an integer greater than or equal to 2, and Li=N−Ki×(Pi−1). When Li=1, Pi−1=Qi; or when Li>1, the indication bit indicating the transmission result of the Lidata blocks is also a first indication bit, that is, Pi=Qi.

In a possible implementation, Kimay be obtained from a response indication manner sent after ithtransmission.

In a possible implementation, Qi=Qi0+Qi1, where each of the Qi0first indication bits is used to indicate a transmission result of Ki0data blocks, each of the Qi1first indication bits is used to indicate a transmission result of Ki1data blocks, both Qi0and Qi1are positive integers, Ki0and Ki1are integers greater than or equal to 2, and Ki0and Ki1are unequal.

In a possible implementation, when X=1, the first data includes the N data blocks, PXis equal to N, and each of the PXindication bits indicates a transmission result of one of the N data blocks. PYis less than N, and the PYindication bits include at least one first indication bit.

According to this implementation, indication precision of a response after initial transmission of target data can be improved.

In a possible implementation, a response indication manner may be specifically set based on different transmission times of the target data. For example, a response indication manner is set for first transmission of the target data, and a response indication manner is set for retransmission of the target data; or a corresponding response indication manner is set for each transmission of the target data.

According to this implementation, flexibility of a response indication manner in the communications system can be improved.

In a possible implementation, an indication manner of any response is agreed on by the first device and the second device, or is sent by the second device to the first device.

This implementation can ensure that a response indication manner used by the first device to generate a response after each transmission of the target data is consistent with a response indication manner used by the second device to parse the response, thereby ensuring transmission reliability and efficiency of the target data.

In a possible implementation, when the second device is the network device, and the first device is the terminal device, the second device may add an indication manner of any response to any of the following information and send the information to the first device:

DCI, a media access control (MAC) control element (CE), radio resource control (RRC) signaling, and a system message, where the system message may include a master information block (MIB) and a system information block (SIB).

In a possible implementation, when the second device is transmitting data blocks of the target data, if determining that some or all of the data blocks may fail to be transmitted in the current transmission due to some special factors (for example, transmission resources are pre-empted), the second device notifies the first device by using indication information. In this way, the first device may determine, based on the indication information, data blocks whose transmission is to fail. This prevents the first device from performing processing operations, such as decoding and storage (for soft combination or check), on the data blocks whose transmission is to fail, thereby saving resources of the first device. After receiving the indication information, the first device deletes the stored data blocks that are determined based on the indication information. Therefore, when the data blocks are retransmitted next time, because the previously transmitted data blocks are not stored, the first device cannot perform soft combination or check on the data blocks. This is equivalent to that the data blocks are transmitted for the first time. To ensure precision of indicating the data blocks by a response generated after the next-time retransmission, optionally, the response includes second indication bits whose quantity is the same as that of the data blocks, and each second indication bit is used to indicate a transmission result of one of the data blocks.

For example, the first data includes MXdata blocks of the N data blocks, and MXis a positive integer less than or equal to N;

before or when sending third data, the second device sends indication information to the first device if determining that data blocks of the third data may fail to be transmitted, where the third data is data in (X−1)thtransmission of the target data, and the third data includes some or all data blocks of the target data;

the first device receives the indication information from the second device, and determines MX0data blocks from the MXdata blocks based on the indication information, where MX0is an integer greater than or equal to 0 and less than or equal to MX; and

the PXindication bits included in the first response include at least MX0second indication bits, and each of the MX0second indication bits is used to indicate a transmission result of one of the MX0data blocks.

According to this implementation, during specific transmission of the target data, if some data blocks of the target data fail to be transmitted due to a special cause (for example, transmission resources are pre-empted), precision of indicating the data blocks by a response generated after next-time retransmission can be ensured.

In a possible implementation, when the communications system supports pre-emption (pre-emption), the indication information is discontinuous transmission indication information. The discontinuous transmission indication is used to indicate a transmission resource. After receiving the indication information, the first device determines that the transmission resource indicated by the discontinuous transmission indication partially overlaps a transmission resource occupied by the second device in the (X−1)thtransmission of the target data, and may determine that transmission of data blocks to be received on the transmission resource indicated by the discontinuous transmission indication fails after the (X−1)thtransmission. A response sent by the first device to the second device after the (X−1)thtransmission indicates that the transmission of the data blocks fails. Therefore, the first device may determine the retransmitted data blocks (namely, the MX0data blocks) from the first data (namely, the MXdata blocks) in the Xthtransmission, and therefore may determine a transmission result of the MX0data blocks and further generate the second response including the MX0second indication bits.

In a possible implementation, when the communications system sets a corresponding response indication manner for each transmission of the target data, after receiving the indication information from the second device, the first device may generate the first response according to the following methods:

First method: The first device no longer generates the first response in a response indication manner that is set for the Xthtransmission, but generates the first response including N indication bits. Each of the N indication bits indicates a transmission result of one of the N data blocks. The N indication bits include the MX0second indication bits.

Second method: The first device still generates the first response in the response indication manner that is set for the Xthtransmission, that is, a transmission result of data blocks other than the MX0data blocks in the N data blocks is still indicated in the response indication manner that is set for the Xthtransmission.

In a possible implementation, when the first device generates the first response by using the first method in the foregoing implementation, the first device may generate a response after (X+1)thtransmission in the response indication manner that is set for the Xthtransmission, or skipping the response indication manner that is set for the Xthtransmission but directly using a response indication manner that is set for the (X+1)thtransmission.

Optionally, in the communications system, the first device and the second device also need to agree on the following content, or the network device or the second device configures the following content after transmission resources are pre-empted in the (X−1)thtransmission: a method for generating a response to be sent after the Xthtransmission, and a response indication manner used to subsequently generate a response after (X+j)thtransmission, where j is an integer greater than 0.

According to a second aspect, an embodiment of this application provides a communication method. The method may be applied to a communications system that includes a terminal device and a network device. A first device is a receiving device of target data in the terminal device and the network device. A second device is a sending device of the target data in the terminal device and the network device. In the method, indication manners of two responses (a first response and a second response) that are separately received by the second device from the first device and that are used to indicate a transmission result of the target data are different.

According to the method, because indications of the two responses that are sent by the first device at different times and that are used to indicate transmission of the same target data may be different, this solution can improve flexibility of a response indication manner. Therefore, the communications system can flexibly adjust indication manners of responses sent at different times to ensure indication precision of the responses while reducing transmission resources of the responses.

In a possible implementation, before the second device receives the first response from the first device, the second device sends first data to the first device, where the first data is data in Xthtransmission of the target data, the first data includes some or all of the target data, the first response is used to indicate a transmission result of the target data after the Xthtransmission, and X is an integer greater than or equal to 1; and before the second device receives the second response from the first device, the second device sends second data to the first device, where the second data is data in Ythtransmission of the target data, the second data includes some or all of the target data, the second response is used to indicate a transmission result of the target data after the Ythtransmission, and Y is an integer greater than X.

According to this implementation, the first device may generate the first response and the second response based on the received transmission results of the target data after the Xthtransmission and the Ythtransmission.

In a possible implementation, when the second device is transmitting data blocks of the target data, if determining that some or all of the data blocks may fail to be transmitted in the current transmission due to some special factors (for example, transmission resources are pre-empted), the second device notifies the first device by using indication information. In this way, the first device may determine, based on the indication information, data blocks whose transmission is to fail. This prevents the first device from performing processing operations, such as decoding and storage (for soft combination or check), on the data blocks whose transmission is to fail, thereby saving resources of the first device. After receiving the indication information, the first device deletes the stored data blocks that are determined based on the indication information. Therefore, when the data blocks are retransmitted next time, because the previously transmitted data blocks are not stored, the first device cannot perform soft combination or check on the data blocks. This is equivalent to that the data blocks are transmitted for the first time. To ensure precision of indicating the data blocks by a response generated after the next-time retransmission, optionally, the response includes second indication bits whose quantity is the same as that of the data blocks, and each second indication bit is used to indicate a transmission result of one of the data blocks.

According to a third aspect, this application provides a first device, including units or modules configured to perform the steps in the first aspect.

According to a fourth aspect, this application provides a second device, including units or modules configured to perform the steps in the second aspect.

According to a fifth aspect, this application provides a first device, including a transceiver, a processor, and a memory. The processor is configured to invoke and execute a computer program stored in the memory, and implement the method provided in the first aspect by sending and receiving data by using the transceiver.

According to a sixth aspect, this application provides a second device, including a transceiver, a processor, and a memory. The processor is configured to invoke and execute a computer program stored in the memory, and implement the method provided in the second aspect by sending and receiving data by using the transceiver.

According to a seventh aspect, this application provides a communications device, including at least one processing element (or chip) configured to perform the method in the first aspect or the second aspect.

According to an eighth aspect, this application provides a program. When being executed by a processor, the program is used to perform the method in any one of the foregoing aspects.

According to a ninth aspect, this application provides a program product, for example, a computer readable storage medium, including the program in the eighth aspect.

According to a tenth aspect, this application provides a chip. The chip is configured to read and execute a computer program stored in a memory, to implement the method in any one of the foregoing aspects.

According to an eleventh aspect, an embodiment of this application provides a chip system. The chip system includes a processor, configured to support either a first device or a second device in implementing a function described in the foregoing corresponding aspects. In a possible implementation, the chip system further includes a memory. The memory is configured to store a program instruction and data that are required for the device. The chip system may include a chip, or may include a chip and another discrete device.

According to a twelfth aspect, an embodiment of this application provides a communications system. The communications system includes a first device configured to implement the first aspect, and a second device configured to implement the second aspect.

In the solution provided in the embodiments of this application, the first device in the communications system separately sends, to the second device, the responses used to indicate the transmission result of the target data: the first response and the second response, where the indication manner of the first response is different from the indication manner of the second response. In this solution, because indications of the two responses that are sent by the first device at different times and that are used to indicate transmission of the same target data may be different, this solution can improve flexibility of a response indication manner. Therefore, the communications system can flexibly adjust indication manners of responses sent at different times to ensure indication precision of the responses while reducing transmission resources of the responses.

