Retuning method and apparatus for SRS coverage enhancement

1. A retuning method, comprising:

determining, by a terminal device, a first resource and a second resource, wherein the first resource is used to send a sounding reference signal, wherein the first resource comprises a first frequency domain resource and at least one symbol of a first subframe, wherein the at least one symbol comprises the last symbol of the first subframe, wherein the second resource is used to send a physical uplink shared channel or a physical uplink control channel, wherein the second resource comprises a second frequency domain resource and a second subframe, wherein all or a part of the first frequency domain resource is not in the second frequency domain resource, wherein the first subframe is the first subframe in two consecutive subframes, and wherein the second subframe is the second subframe in the two consecutive subframes; and

determining, by the terminal device in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning from the first resource to the second resource, a guard period for the retuning, wherein the guard period is used to forbid the terminal device to send an uplink signal in the guard period.

2. The method according to claim 1 , wherein the determining, by the terminal device in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning, a guard period for the retuning comprises:

in response to one symbol being required for retuning, determining, by the terminal device, that the guard period is in the first symbol of a plurality of symbols in the second subframe that are used to send the physical uplink shared channel.

3. The method according to claim 1 , wherein the determining, by the terminal device in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning, a guard period for the retuning comprises:

in response to two symbols being required for retuning and the second resource is used to send the physical uplink control channel, determining, by the terminal device, that the guard period is in the last symbol of the first subframe and the first symbol of a plurality of symbols in the second subframe that are used to send the physical uplink control channel.

4. The method according to claim 1 , wherein the determining, by the terminal device in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning, a guard period for the retuning comprises:

in response to two symbols being required for retuning and the second resource is used to send the physical uplink shared channel, determining, by the terminal device, that the guard period is in the first two symbols of a plurality of consecutive symbols in the second subframe that are used to send the physical uplink shared channel.

5. The method according to claim 1 , wherein before the determining, by the terminal device in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning, a guard period for the retuning, the method further comprises:

receiving, by the terminal device, first indication information, wherein the first indication information is used to instruct the terminal device to determine the guard period in at least one of the first subframe or the second subframe.

6. The method according to claim 5 , wherein the receiving, by the terminal device, first indication information comprises:

receiving, by the terminal device, radio resource control signaling, wherein the radio resource control signaling carries the first indication information.

7. The method according to claim 1 , wherein bandwidth of the first frequency domain resource is equal to transmission bandwidth of the sounding reference signal, and wherein the second frequency domain resource is a narrowband resource.

8. The method according to claim 1 , wherein the terminal device is a bandwidth-reduced low-complexity (BL) terminal device, or a coverage enhanced (CE) terminal device.

9. A retuning apparatus, comprising:

a memory storing program instructions; and

at least one processor coupled to the memory, wherein the program instructions, when executed by the at least one processor, cause the apparatus to:

determine a first resource and a second resource, wherein the first resource is used to send a sounding reference signal, wherein the first resource comprises a first frequency domain resource and at least one symbol of a first subframe, wherein the at least one symbol comprises the last symbol of the first subframe, wherein the second resource is used to send a physical uplink shared channel or a physical uplink control channel, wherein the second resource comprises a second frequency domain resource and a second subframe, wherein all or a part of the first frequency domain resource is not in the second frequency domain resource, wherein the first subframe is the first subframe in two consecutive subframes, and wherein the second subframe is the second subframe in the two consecutive subframes; and

determine, in at least one of the first subframe or the second subframe based on a quantity of symbols required for retuning from the first resource to the second resource, a guard period for the retuning, wherein the guard period is used to forbid the apparatus to send an uplink signal in the guard period.

10. The apparatus according to claim 9 , wherein the program instructions, when executed by the at least one processor, cause the apparatus to determine, in response to one symbol being required for retuning, that the guard period is in the first symbol of a plurality of symbols in the second subframe that are used to send the physical uplink shared channel.

11. The apparatus according to claim 9 , wherein the program instructions, when executed by the at least one processor, cause the apparatus to determine, in response to two symbols being required for retuning and the second resource is used to send the physical uplink control channel, that the guard period is in the last symbol of the first subframe and the first symbol of a plurality of symbols in the second subframe that are used to send the physical uplink control channel.

12. The apparatus according to claim 9 , wherein the program instructions, when executed by the at least one processor, cause the apparatus to determine, in response to two symbols being required for retuning and the second resource is used to send the physical uplink shared channel, that the guard period is in the first two symbols of a plurality of consecutive symbols in the second subframe that are used to send the physical uplink shared channel.

13. The apparatus according to claim 9 , the program instructions, when executed by the at least one processor, further cause the apparatus to:

receive first indication information before the determining, in at least one of the first subframe or the second subframe, the guard period for retuning, wherein the first indication information is used to instruct the apparatus to determine the guard period in at least one of the first subframe or the second subframe.

14. The apparatus according to claim 13 , the program instructions, when executed by the at least one processor, cause the apparatus to:

receive radio resource control signaling, wherein the radio resource control signaling carries the first indication information.

15. The apparatus according to claim 9 , wherein bandwidth of the first frequency domain resource is equal to transmission bandwidth of the sounding reference signal, and wherein the second frequency domain resource is a narrowband resource.

16. The apparatus according to claim 9 , wherein the apparatus is a bandwidth-reduced low-complexity (BL) terminal device, or a coverage enhanced (CE) terminal device.

17. A network device, comprising:

a memory storing program instructions; and

a processor coupled to the memory, wherein the program instructions, when executed by the processor, cause the network device to:

determine, based on a quantity of symbols required for retuning from a first resource to a second resource by a terminal device, a guard period for the retuning, wherein the guard period is in at least one of a first subframe or a second subframe, wherein the guard period is used to forbid the terminal device to send an uplink signal in the guard period, wherein the first resource is used for receiving a sounding reference signal, wherein the first resource comprises a first frequency domain resource and at least one symbol of the first subframe, wherein the at least one symbol comprises the last symbol of the first subframe, wherein the second resource is used for receiving a physical uplink control channel or a physical uplink shared channel, wherein the second resource comprises a second frequency domain resource and the second subframe, wherein all or a part of the first frequency domain resource is not in the second frequency domain resource, wherein the first subframe is the first subframe in two consecutive subframes, and wherein the second subframe is the second subframe in the two consecutive subframes; and

determine that no uplink signal from the terminal device exists in the guard period.

18. The network device according to claim 17 , wherein the program instructions, when executed by the processor, cause the network device to determine, in response to one symbol being required for the retuning from the first resource to the second resource by the terminal device, that the guard period is in the first symbol of a plurality of symbols in the second subframe that are used for receiving the physical uplink shared channel.

19. The network device according to claim 17 , wherein the program instructions, when executed by the processor, cause the network device to determine, in response to two symbols being required for the retuning from the first resource to the second resource by the terminal device and the second resource is used for receiving the physical uplink control channel, that the guard period is in the last symbol of the first subframe and the first symbol of a plurality of symbols in the second subframe that are used for receiving the physical uplink control channel.

20. The network device according to claim 17 , wherein the program instructions, when executed by the processor, cause the network device to determine, in response to two symbols being required for the retuning from the first resource to the second resource by the terminal device and the second resource is used for receiving the physical uplink shared channel, that the guard period is in the first two symbols of a plurality of consecutive symbols in the second subframe that are used to send the physical uplink shared channel.