Method and apparatus for reporting RSRP

1. A user equipment (UE), comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and

at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to:

obtain a first measured RSRP value;

receive a first message from a base station;

select a first quantization table from one or more quantization tables according to the first message, wherein the one or more quantization tables comprises a non-uniform quantization table;

convert the first measured RSRP value to a first quantized RSRP value according to the first quantization table; and

send the first quantized RSRP value to the base station,

wherein the at least one processor is further configured to execute the computer-executable instructions to:

obtain a second measured RSRP value;

obtain a first differential RSRP value by calculating a difference value between the first measured RSRP value and the second measured RSRP value;

convert the first differential RSRP value to a first quantized differential RSRP value according to a second quantization table that is not among the one or more quantization tables; and

send the first quantized differential RSRP value to the base station.

2. The UE of claim 1 , wherein the non-uniform quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein the plurality of RSRP ranges comprises a first RSRP range and a second RSRP range, wherein a first power level of the first RSRP range is lower than a second power level of the second RSRP range, and the first RSRP range is larger than the second RSRP range.

3. The UE of claim 1 , wherein the non-uniform quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein each RSRP range has a corresponding power level, and the RSRP range decreases as the corresponding power level increases.

4. The UE of claim 1 , wherein the second quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein the plurality of RSRP ranges comprises a first RSRP range and a second RSRP range, wherein a first power level of the first RSRP range is lower than a second power level of the second RSRP range, and the first RSRP range is larger than the second RSRP range.

5. The UE of claim 1 , wherein the second quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, and each of the plurality of RSRP ranges is equal to a step size, and the step size is greater than 2 dB.

6. The UE of claim 5 , wherein the step size is equal to 6 dB.

7. The UE of claim 5 , wherein the at least one processor is further configured to execute the computer-executable instructions to:

receive a second message from the base station, wherein the second message indicates the step size.

8. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:

obtain a plurality of measured RSRP values, wherein the plurality of measured RSRP values include the first measured RSRP value;

select a reference RSRP value among the plurality of measured RSRP values;

obtain a plurality of differential RSRP values by calculating a plurality of difference values between the reference RSRP value and each of the plurality of measured RSRP values;

convert the plurality of differential RSRP values to a plurality of quantized differential RSRP values according to a second quantization table that is not among the one or more quantization tables; and

send the plurality of quantized differential RSRP values to the base station.

9. The UE of claim 1 , wherein the non-uniform quantization table is fixed and stored in the UE.

10. The UE of claim 1 , wherein the one or more quantization tables further comprises a uniform quantization table.

11. The UE of claim 1 , wherein the first message comprises one of a radio resource control (RRC) message, a medium access control (MAC) control element (CE) message, and a downlink control information (DCI) message.

12. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:

convert the first measured RSRP value to the first quantized RSRP value according to a default quantization table, when the UE does not successfully receive the first message from the base station.

13. A method of reporting RSRP performed by a UE, the method comprising:

obtaining a first measured RSRP value;

receiving a first message from a base station;

selecting a first quantization table from one or more quantization tables according to the first message, wherein the one or more quantization tables comprises a non-uniform quantization table;

converting the first measured RSRP value to a first quantized RSRP value according to the first quantization table;

sending the first quantized RSRP value to the base station,

obtaining a second measured RSRP value;

obtaining a first differential RSRP value by calculating a difference value between the first measured RSRP value and the second measured RSRP value;

converting the first differential RSRP value to a first quantized differential RSRP value according to a second quantization table that is not among the one or more quantization tables; and

sending the first quantized differential RSRP value to the base station.

14. The method of claim 13 , wherein the non-uniform quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein the plurality of RSRP ranges comprises a first RSRP range and a second RSRP range, wherein a first power level of the first RSRP range is lower than a second power level of the second RSRP range, and the first RSRP range is larger than the second RSRP range.

15. The method of claim 13 , wherein the non-uniform quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein each RSRP range has a corresponding power level, and the RSRP range decreases as the corresponding power level increases.

16. The method of claim 13 , wherein the second quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, wherein the plurality of RSRP ranges comprises a first RSRP range and a second RSRP range, wherein a first power level of the first RSRP range is lower than a second power level of the second RSRP range, and the first RSRP range is larger than the second RSRP range.

17. The method of claim 13 , wherein the second quantization table maps a plurality of RSRP ranges to a plurality of quantized outputs respectively, and each of the plurality of RSRP ranges is equal to a step size, and the step size is greater than 2 dB.

18. The method of claim 17 , wherein the step size is equal to 6 dB.

19. The method of claim 17 , further comprising:

receiving a second message from the base station, wherein the second message indicates the step size.

20. The method of claim 13 , further comprising:

obtaining a plurality of measured RSRP values, wherein the plurality of measured RSRP values include the first measured RSRP value;

selecting a reference RSRP value among the plurality of measured RSRP values;

obtaining a plurality of differential RSRP values by calculating a plurality of difference values between the reference RSRP value and each of the plurality of measured RSRP values;

converting the plurality of differential RSRP values to a plurality of quantized differential RSRP values according to a second quantization table that is not among the one or more quantization tables; and

sending the plurality of quantized differential RSRP values to the base station.

21. The method of claim 13 , wherein the non-uniform quantization table is fixed and stored in the UE.

22. The method of claim 13 , wherein the one or more quantization tables further comprises a uniform quantization table.

23. The method of claim 13 , wherein the first message comprises one of a radio resource control (RRC) message, a medium access control (MAC) control element (CE) message, and a downlink control information (DCI) message.

24. The method of claim 13 , further comprising:

converting the first measured RSRP value to the first quantized RSRP value according to a default quantization table, when the UE does not successfully receive the first message from the base station.