Communication method and apparatus for reducing a retransmission process delay

1 . A communication method, comprising:

receiving, by a terminal device, a first physical downlink shared channel (PDSCH) from a network device;

decoding, by the terminal device, data carried on the first PDSCH to obtain a decoding result;

determining, by the terminal device whether the result of the decoding of the data carried on the first PDSCH is correct;

based on determining the result of the decoding of the data carried on the first PDSCH is not correct, reducing a transmission latency by directly sending by the terminal device a sounding reference signal (SRS) to the network device on a first time-frequency resource without waiting for scheduling from the network device to reduce time from unsuccessfully decoding the first PDSCH to a time the SRS is sent to the network device by the terminal device, and receiving, by the terminal device, a retransmission of the first PDSCH from the network device using an adjusted retransmission parameter of the first PDSCH based on a result of a measurement of the SRS sent without waiting on rescheduling from the network device; and

based on determining the result of the decoding of the data carried on the first PDSCH is correct, sending by the terminal device feedback information of the first PDSCH to the network device, wherein the feedback information includes acknowledgement information.

2 . The method according to claim 1 , in response to the data carried on the first PDSCH being successfully decoded by the terminal device, the method further comprises:

skipping sending, by the terminal device, the SRS to the network device on the first time-frequency resource.

3 . The method according to claim 1 , wherein the SRS is an aperiodic SRS, and the method further comprises:

receiving, by the terminal device, first downlink control information (DCI) from the network device, wherein the first DCI indicates the first time-frequency resource.

4 . The method according to claim 3 , further comprising using, by the terminal device, the first DCI to schedule the first PDSCH.

5 . The method according to claim 1 , wherein the first time-frequency resource is the same as a time-frequency resource used to carry the feedback information of the first PDSCH.

6 . The method according to claim 1 , wherein the method further comprises:

receiving, by the terminal device, first indication information from the network device, wherein the first indication information indicates a frequency domain resource of the first time-frequency resource; and

determining, by the terminal device, a first time domain resource, wherein the first time domain resource is a time domain resource of the first time-frequency resource, and there is a first correspondence between the first time domain resource and a second time domain resource, wherein the second time domain resource is a time domain resource occupied by the first PDSCH, a time domain resource occupied by the feedback information of the first PDSCH, or a time domain resource occupied by a second Downlink Control Information (DCI), and using, by the terminal device, the second DCI to schedule the first PDSCH.

7 . The method according to claim 1 , wherein the SRS is a periodic SRS, and the method further comprises:

receiving, by the terminal device, first configuration information from the network device, using, by the terminal device, the first configuration information to determine a transmission periodicity of the periodic SRS and a first time-frequency resource set for carrying the periodic SRS, the first time-frequency resource is in the first time-frequency resource set and whose start moment is not earlier than a start moment of a symbol S1, and the symbol S1 is the 1st symbol after a first time length starting from an end moment of a second time domain resource, wherein the second time domain resource is a time domain resource occupied by the first PDSCH, a time domain resource occupied by the feedback information of the first PDSCH, or a time domain resource occupied by a second Downlink Control Information (DCI), and using, by the terminal device, the second DCI to schedule the first PDSCH.

8 . A communication method, comprising:

sending, by a network device, a first physical downlink shared channel (PDSCH) to a terminal device for decoding by the terminal device to determine, by the terminal device, whether a result of the decoding of data carried on the first PDSCH is correct;

based the result of the decoding of the data carried on the first PDSCH being determined not to be correct, receiving, by the network device, feedback information of the first PDSCH from the terminal device, and the feedback information being negative acknowledgement information, and receiving, by the network device, a sounding reference signal (SRS) directly sent from the terminal device on a first time-frequency resource without waiting for scheduling from the network device to reduce time from unsuccessfully decoding the first PDSCH to a time the SRS is sent to the network device, and sending, by the network device, a retransmission of the first PDSCH to the terminal device using an adjusted retransmission parameter of the first PDSCH based on a result of a measurement of the SRS sent without waiting on rescheduling from the network device; and

based the result of the decoding of the data carried on the first PDSCH being determined not to be correct, not receiving, by the network device, the feedback information of the first PDSCH from the terminal device, and receiving, by the network device, the SRS directly sent from the terminal device on the first time-frequency resource without waiting for the scheduling from the network device.

9 . The method according to claim 8 , wherein the SRS is an aperiodic SRS, and the method further comprises:

sending, by the network device, first downlink control information (DCI) to the terminal device, wherein the first DCI indicates the first time-frequency resource.

10 . The method according to claim 9 , wherein further comprising using, by the network device, the first DCI to schedule the first PDSCH.

11 . The method according to claim 8 , wherein the first time-frequency resource is the same as a time-frequency resource used to carry the feedback information of the first PDSCH.

12 . The method according to claim 8 , wherein the method further comprises:

sending, by the network device, first indication information to the terminal device, wherein the first indication information indicates a frequency domain resource of the first time-frequency resource; and

determining, by the network device, a first time domain resource, wherein the first time domain resource is a time domain resource of the first time-frequency resource, and there is a first correspondence between the first time domain resource and a second time domain resource, wherein the second time domain resource is a time domain resource occupied by the first PDSCH, a time domain resource occupied by the feedback information of the first PDSCH, or a time domain resource occupied by a second Downlink Control Information (DCI), and using, by the network device, the second DCI to schedule the first PDSCH.

13 . A communication apparatus, comprising:

a memory, configured to store a computer program or instructions;

a processor, connected to the memory; and

a transceiver, configured to receive a first physical downlink shared channel (PDSCH) from a network device;

wherein the processor is configured to execute computer-readable instructions to:

receive, via the transceiver, a first physical downlink shared channel (PDSCH) from a network device, decode data carried on the first PDSCH to obtain a decoding result, determine whether the result of the decoding of the data carried on the first PDSCH is correct, reduce a transmission latency by directly sending, via the transceiver, a sounding reference signal (SRS) to the network device on a first time-frequency resource without waiting for scheduling from the network device to reduce time from unsuccessfully decoding the first PDSCH to a time the SRS is sent to the network device, and receive a retransmission of the first PDSCH from the network device using an adjusted retransmission parameter of the first PDSCH based on a result of a measurement of the SRS sent without waiting on rescheduling from the network device; and send, via the transceiver, feedback information of the first PDSCH to the network device in response to the result of the decoding by the processor of the data carried on the first PDSCH by the processor is correct, wherein the feedback information includes acknowledgement information.

14 . The apparatus according to claim 13 , in response to the data carried on the first PDSCH being successfully decoded, the processor is configured to:

skip sending the SRS to the network device on the first time-frequency resource.

15 . The apparatus according to claim 13 , wherein the SRS is an aperiodic SRS, and the processor further configured to:

receive, via the transceiver, first downlink control information (DCI) from the network device, wherein the first DCI indicates the first time-frequency resource.

16 . The apparatus according to claim 13 , wherein the processor is further configured to:

receive, via the transceiver, first indication information from the network device, wherein the first indication information indicates a frequency domain resource of the first time-frequency resource; and

determine a first time domain resource, wherein the first time domain resource is a time domain resource of the first time-frequency resource, and there is a first correspondence between the first time domain resource and a second time domain resource, wherein the second time domain resource is a time domain resource occupied by the first PDSCH, a time domain resource occupied by the feedback information of the first PDSCH, or a time domain resource occupied by a second Downlink Control Information (DCI), and the processor is further configured to use the second DCI to schedule the first PDSCH.

17 . A communication apparatus, comprising:

a memory, configured to store a computer program or instructions;

a processor coupled to the memory; and

a transceiver; configured to send a first physical downlink shared channel (PDSCH) to a terminal device; and

wherein the processor is configured to execute the computer program or instructions to:

receive, via the transceiver, a first physical downlink shared channel (PDSCH) from a network device, decode data carried on the first PDSCH to obtain a decoding result, determine whether the result of the decoding of the data carried on the first PDSCH is correct, directly receive, via the transceiver, a sounding reference signal (SRS) sent from the terminal device on a first time-frequency resource without the terminal device waiting for scheduling on a first time-frequency resource to reduce time from unsuccessfully decoding the first PDSCH to a time the SRS is sent by the terminal device, and in response to feedback information of the first PDSCH being received from the terminal device indicating the result of the decoding by the terminal device of the data on the first PDSCH is determined to not be correct, the feedback information is negative acknowledgement information; and configured to receive the SRS from the terminal device on the first time-frequency resource in response to the feedback information of the first PDSCH not being received from the terminal device indicating the terminal device determined the result of the decoding of the data carried on the first PDSCH is incorrect.

18 . The apparatus according to claim 17 , wherein the SRS is an aperiodic SRS, and the processor is further configured to:

send, via the transceiver, first downlink control information (DCI) to the terminal device, wherein the first DCI indicates the first time-frequency resource.

19 . The apparatus according to claim 17 , wherein the first time-frequency resource is the same as a time-frequency resource used to carry the feedback information of the first PDSCH.

20 . The apparatus according to claim 17 , wherein the processor is further configured to:

send, via the transceiver, first indication information to the terminal device, wherein the first indication information indicates a frequency domain resource of the first time-frequency resource; and

determine a first time domain resource, wherein the first time domain resource is a time domain resource of the first time-frequency resource, and there is a first correspondence between the first time domain resource and a second time domain resource, wherein the second time domain resource is a time domain resource occupied by the first PDSCH, a time domain resource occupied by the feedback information of the first PDSCH, or a time domain resource occupied by a second Downlink Control Information (DCI), and the processor is configured to use the second DCI to schedule the first PDSCH.