Method and apparatus for reference signal configuration of a wireless communication system

1. A method comprising:

receiving, by a base station, a plurality of uplink sequences from an uplink channel;

performing, by the base station, an optimal combining procedure on the plurality of uplink sequences to output a combined result of the plurality of uplink sequences;

determining, by the base station, channel signature information based on the combined result;

detecting, by the base station, a plurality of complex signals at peak positions from the plurality of uplink sequences based on the channel signature information;

estimating, by the base station, a correlation level based on the plurality of complex signals; and

determining a density of a reference signal and a Modulation and Coding Scheme based on the correlation level;

wherein the channel signature information comprises a power delay profile.

2. The method of claim 1 , wherein the uplink channel is a Physical Random Access Channel (PRACH).

3. The method of claim 2 , wherein the uplink sequences for the PRACH are PRACH sequences.

4. The method of claim 1 , wherein the uplink channel is a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

5. The method of claim 4 , wherein the uplink sequences for the PUCCH or the PUSCH are Demodulation Reference Signals (DM-RSs).

6. The method of claim 1 , wherein optimal combining procedure is a Maximum Ratio Combining (MRC) procedure.

7. The method of claim 1 , further comprising: determining, by the base station, a plurality of power peak levels from the plurality of uplink sequences based on the power delay profile; and estimating, by the base station, a frequency offset based on the plurality of power peak levels.

8. The method of claim 7 , further comprising: compensating, by the based station, the frequency offset based on the channel signature information.

9. The method of claim 1 , wherein the reference signal is a Demodulation Reference Signal (DM-RS) or a Phase Tracking Reference Signal (PT-RS).

10. A base station, 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:

receive a plurality of uplink sequences from an uplink channel;

perform an optimal combining procedure on the plurality of uplink sequences to output a combined result of the plurality of uplink sequences;

determine channel signature information based on the combined result;

detect a plurality of complex signals at peak positions from the plurality of uplink sequences based on the channel signature information;

estimate a correlation level based on the plurality of complex signals; and

determine a density of a reference signal and a Modulation and Coding Scheme based on the correlation level;

wherein the channel signature information comprises a power delay profile.

11. The base station of claim 10 , wherein the uplink channel is a Physical Random Access Channel (PRACH).

12. The base station of claim 11 , wherein the uplink sequences for the PRACH are PRACH sequences.

13. The base station of claim 10 , wherein the uplink channel is a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

14. The base station of claim 13 , wherein the uplink sequences for the PUCCH or the PUSCH are Demodulation Reference Signals (DM-RSs).

15. The base station of claim 10 , wherein optimal combining procedure is a Maximum Ratio Combining (MRC) procedure.

16. The base station of claim 10 , wherein the at least one processor is further configured to execute the computer-executable instructions to: determine a plurality of power peak levels from the plurality of uplink sequences based on the power delay profile; and estimate a frequency offset based on the plurality of power peak levels.

17. The base station of claim 16 , wherein the at least one processor is further configured to execute the computer-executable instructions to: compensate the frequency offset based on the channel signature information.

18. The base station of claim 10 , wherein the reference signal is a Demodulation Reference Signal (DM-RS) or a Phase Tracking Reference Signal (PT-RS).