Method, base station, and user equipment for reporting channel state information

1. A method for reporting channel state information, wherein the method comprises:

receiving, by a base station, a first reference signal sent by user equipment;

sending, by the base station, a first parameter set and a second reference signal to the user equipment, wherein the first parameter set is obtained by the base station by measuring the first reference signal; and

receiving, by the base station, a third parameter set sent by the user equipment, wherein the third parameter set comprises a relative value between a parameter in a second parameter set and a parameter in the first parameter set, wherein

the second parameter set is obtained by the user equipment by measuring the second reference signal, and the third parameter set and the first parameter set are used by the base station to determine a precoding matrix.

2. The method according to claim 1 , wherein the first parameter set comprises parameters of uplink channels from n ports of the user equipment to the base station, and the second parameter set comprises parameters of downlink channels from the base station to m ports of the user equipment, wherein the m ports comprise the n ports, and n and m are positive integers.

3. The method according to claim 1 , wherein the relative value between the parameter in the second parameter and the parameter in the first parameter comprises one or more of a difference between, a ratio between, and a sum of the parameter in the second parameter and the parameter in the first parameter.

4. The method according to claim 1 , wherein the first parameter set comprises a first base vector indicator set;

the first base vector indicator set comprises at least one first base vector indicator, and the at least one first base vector indicator is used to indicate at least one first base vector in a first base vector set; and

the second parameter set comprises a second base vector indicator set, the second base vector indicator set comprises at least one second base vector indicator, and the at least one second base vector indicator is used to indicate at least one second base vector in a second base vector set.

5. The method according to claim 4 , wherein the third parameter set comprises a relative value between the at least one second base vector indicator and the at least one first base vector indicator.

6. A method for reporting channel state information, wherein the method comprises:

sending, by user equipment, a first reference signal to a base station;

receiving, by the user equipment, a first parameter and a second reference signal that are sent by the base station, wherein the first parameter set is obtained by the base station by measuring the first reference signal; and

sending, by the user equipment, a third parameter set to the base station, wherein the third parameter set comprises a relative value between a parameter in a second parameter set and a parameter in the first parameter set, wherein

the second parameter set is obtained by the user equipment by measuring the second reference signal, and the third parameter set and the first parameter set are used by the base station to determine a precoding matrix.

7. The method according to claim 6 , wherein the first parameter set comprises parameters of uplink channels from n ports of the user equipment to the base station, and the second parameter set comprises parameters of downlink channels from the base station to m ports of the user equipment, wherein the m ports comprise the n ports, and n and m are positive integers.

8. The method according to claim 6 , wherein the relative value between the parameter in the second parameter and the parameter in the first parameter comprises one or more of a difference between, a ratio between, and a sum of the parameter in the second parameter and the parameter in the first parameter.

9. The method according to claim 6 , wherein

the first parameter set comprises a first base vector indicator set, the first base vector indicator set comprises at least one first base vector indicator, and the at least one first base vector indicator is used to indicate at least one first base vector in a first base vector set; and

the second parameter set comprises a second base vector indicator set, the second base vector indicator set comprises at least one second base vector indicator, and the at least one second base vector indicator is used to indicate at least one second base vector in a second base vector set.

10. The method according to claim 9 , wherein the third parameter set comprises a relative value between the at least one second base vector indicator and the at least one first base vector indicator.

11. Apparatus for reporting channel state information, wherein the apparatus comprises:

a transmitter, configured to send a first reference signal to a base station;

a receiver, configured to receive a first parameter and a second reference signal that are sent by the base station, wherein the first parameter set is obtained by the base station by measuring the first reference signal; wherein

the transmitter is further configured to send a third parameter set to the base station, wherein the third parameter set comprises a relative value between a parameter in a second parameter set and a parameter in the first parameter set; and

a processor, wherein the second parameter set is obtained by the processor by measuring the second reference signal, and the third parameter set and the first parameter set are used by the base station to determine a precoding matrix.

12. The apparatus according to claim 11 , wherein the first parameter set comprises parameters of uplink channels from n ports of the apparatus to the base station, and the second parameter set comprises parameters of downlink channels from the base station to m ports of the apparatus, wherein the m ports comprise the n ports, and n and m are positive integers.

13. The apparatus according to claim 11 , wherein the relative value between the parameter in the second parameter and the parameter in the first parameter comprises one or more of a difference between, a ratio between, and a sum of the parameter in the second parameter and the parameter in the first parameter.

14. The apparatus according to claim 11 , wherein the first parameter set comprises a first base vector indicator set, the first base vector indicator set comprises at least one first base vector indicator, and the at least one first base vector indicator is used to indicate at least one first base vector in a first base vector set; and

the second parameter set comprises a second base vector indicator set, the second base vector indicator set comprises at least one second base vector indicator, and the at least one second base vector indicator is used to indicate at least one second base vector in a second base vector set.

15. The apparatus according to claim 14 , wherein the third parameter set comprises a relative value between the at least one second base vector indicator and the at least one first base vector indicator.

16. The apparatus according to claim 14 , wherein the third parameter set comprises a relative value between second base vector amplitude information and first base vector amplitude information, wherein

the first base vector amplitude information is amplitude information of the at least one first base vector, the second base vector amplitude information is amplitude information of the at least one second base vector, and the second base vector amplitude information is obtained by the processor based on the second reference signal and the first parameter set.

17. The apparatus according to claim 14 , wherein the third parameter set comprises a relative value between a second base vector combination coefficient phase and a first base vector combination coefficient phase, the first base vector combination coefficient phase is a combination coefficient phase of the at least one first base vector, and the second base vector combination phase is a combination coefficient phase of the at least one second base vector; and

the first base vector combination coefficient phase is obtained by the processor based on the second reference signal and the first parameter set.

18. The apparatus according to claim 11 , wherein the first reference signal comprises a sounding reference signal SRS.

19. The apparatus according to claim 11 , wherein the second reference signal comprises a channel state information-reference signal CSI-RS.

20. The apparatus according to claim 11 , that the third parameter set and the first parameter set are used by the base station to determine a precoding matrix comprises:

the third parameter set is used by the base station to correct the first parameter set, to obtain the second parameter set; and

the precoding matrix is determined based on the second parameter set.