Method and system for per-cell interference estimation for interference suppression
View Patent ↗A wireless system may receive a plurality of multipath signals from a plurality of transmitters and allocate per-cell modules for generating an interference suppressed signal from the multipath signals. Data symbols may be sequentially processed in the received multipath signals utilizing the per-cell modules and subtracting the processed symbols from a residual buffer storing the received multipath signals. Desired information received from one or more of the transmitters may be recovered utilizing the interference suppressed signal. Timing of the data symbols may be correlated utilizing a cell chip combiner. The data symbols may be descrambled utilizing conjugated scrambling codes associated with one of the plurality of transmitters. Orthogonal variable spreading factor (OVSF) codes may be generated utilizing a Walsh transform on the data symbols. Power levels of the OVSF codes may be estimated and estimated signals may be generated based on the OVSF codes and the estimated power levels.
1. A method for processing a multipath signal in a receiver system including one or more processors and/or circuits, the method comprising:
generating, by the one or more processors and/or circuits, a combined chip-level signal from a plurality of path signals of the multipath signal and corresponding channel estimation parameters;
processing the combined chip-level signal to generate an interference suppressed symbol-level signal for at least one user;
generating an interference suppressed chip-level signal for the at least one user from the interference suppressed symbol-level signal and the corresponding channel estimation parameters;
generating an estimated chip-level signal from the interference suppressed chip-level signal for the at least one user;
subtracting the estimated chip-level signal from the multipath signal to generate a multipath signal residue; and
recovering user-specific information from the interference suppressed symbol-level signal for the at least one user and the multipath signal residue.
2. The method according to claim 1 , further comprising:
correlating timing of data symbols received at the receiver system from corresponding sources utilizing a cell chip combiner.
3. The method according to claim 1 , wherein the processing of the combined chip-level signal comprises:
descrambling the combined chip-level signal utilizing scrambling codes associated with a base transceiver station.
4. The method according to claim 3 , further comprising:
generating a plurality of orthogonal variable spreading factor (OVSF) codes utilizing a Walsh transform, and
wherein the processing of the combined chip-level signal further comprises:
despreading the combined chip-level signal utilizing the OVSF codes.
5. The method according to claim 4 , further comprising:
estimating power levels of the OVSF codes.
6. The method according to claim 5 , wherein generating the interference suppressed chip-level signal for the at least one user comprises:
spreading the interference suppressed symbol-level signal for the at least one user utilizing the OVSF codes and the estimated power levels.
7. The method according to claim 6 ,
wherein the multipath signal is received by a plurality of antennas of the receiver system,
wherein the multipath signal residue comprises a plurality of residual signals associated with the plurality of antennas, and
wherein the subtracting comprises:
subtracting an estimated chip-level signal associated with an antenna of the plurality of antennas from a corresponding path signal of the multipath signal.
8. The method according to claim 1 , further comprising:
processing the multipath signal residue to generate a symbol-level signal residue for the at least one user; and
generating a plurality of addback data symbols for the at least one user from an additive sum of the symbol-level signal residue for the at least one user and a corresponding interference suppressed symbol-level signal.
9. The method according to claim 8 , further comprising:
generating an updated interference suppressed symbol-level signal for the at least one user from the plurality of addback data symbols and a plurality of weighting factor values.
10. The method according to claim 9 , further comprising:
generating an incremental signal for the at least one user from a subtractive difference between the updated interference suppressed symbol-level signal for the at least one user and the plurality of addback data symbols for the at least one user.
11. A system for wireless communication, the system comprising:
one or more antennas configured to receive a multipath signal; and
one or more processors and/or circuits for use in a wireless communication system, the one or more processors and/or circuits being configured to:
generate a combined chip-level signal from a plurality of path signals of the multipath signal and corresponding channel estimation parameters;
process the combined chip-level signal to generate an interference suppressed symbol-level signal for at least one user;
generate an interference suppressed chip-level signal for the at least one user from the interference suppressed symbol-level signal and the corresponding channel estimation parameters;
generate an estimated chip-level signal from the interference suppressed chip-level signal for the at least one user;
subtract the estimated chip-level signal from the multipath-signal to generate a multipath signal residue; and
recover user-specific information from the interference suppressed symbol-level signal for the at least one user and the multipath signal residue.
12. The system according to claim 11 , wherein the one or more processors and/or circuits are further configured to correlate timing of data symbols received from corresponding sources utilizing a cell chip combiner.
13. The system according to claim 11 , wherein the one or more processors and/or circuits are further configured to descramble the combined chip-level signal utilizing scrambling codes associated with a base transceiver station.
14. The system according to claim 13 , wherein the one or more processors and/or circuits are further configured to:
generate a plurality of orthogonal variable spreading factor (OVSF) codes utilizing a Walsh transform; and
despread the combined chip-level signal utilizing the OVSF codes to generate the interference suppressed symbol-level signal.
15. The system according to claim 14 , wherein the one or more processors and/or circuits are configured to estimate power levels of the OVSF codes.
16. The system according to claim 15 , wherein the one or more processors and/or circuits are further configured to generate the interference suppressed chip-level signal for the at least one user by spreading the interference suppressed symbol-level signal for the at least one user utilizing the OVSF codes and the estimated power levels.
17. The system according to claim 16 , wherein the multipath signal residue comprises a plurality of residual signals associated with the one or more antennas, and
wherein the one or more processors and/or circuits are configured to calculate the multipath signal residue by subtracting an estimated chip-level signal associated with an antenna of the one or more antennas from a corresponding path signal of the multipath signal.
18. The system according to claim 11 , wherein the one or more processors and/or circuits are configured to:
process the multipath signal residue to generate a symbol-level signal residue for the at least one user; and
generate a plurality of addback data symbols for the at least one user from an additive sum of the symbol-level signal residue for the at least one user and a corresponding interference suppressed symbol-level signal.
19. The system according to claim 18 , wherein the one or more processors and/or circuits are configured to generate an updated interference suppressed symbol-level signal for the at least one user from the plurality of addback data symbols and a plurality of weighting factor values.
20. The system according to claim 19 , wherein the one or more processors and/or circuits are configured to generate an incremental signal for the at least one user from a subtractive difference between the interference suppressed symbol-level signal for the at least one user and the plurality of addback data symbols for the at least one user.