Frequency dependent I/Q imbalance compensation
View Patent ↗A method and system for compensating for frequency dependent phase and amplitude imbalances is provided. A plurality of frequency sub-bands is extracted from a received wideband signal. Each of the plurality of frequency sub-bands is compensated to produce an associated plurality of compensated frequency sub-bands. The compensated sub-bands are summed in order to produce a compensated signal.
1. A method for compensating for frequency dependent imbalances comprising:
extracting a plurality of frequency sub-bands from a received wideband signal;
compensating each of the plurality of frequency sub-bands to produce an associated plurality of compensated frequency sub-bands, wherein compensating each of the plurality of frequency sub-bands comprises:
deriving blind signal separation parameters via a block estimation technique for each of the plurality of frequency sub-bands, wherein the blind signal separation parameters represent unknown imbalance parameters digitally estimated without training signals; and
removing an interference component from each of the plurality of frequency sub-bands based on the blind signal separation parameters; and
summing, by a processor, the compensated frequency sub-bands to produce a compensated signal.
2. The method of claim 1 , wherein extracting a plurality of frequency sub-bands is performed by a sub-band coder.
3. The method of claim 1 , wherein the step of compensating is performed by a frequency dependent algorithm.
4. The method of claim 1 , wherein the step of compensating is performed by a frequency independent algorithm.
5. A system for compensating for frequency dependent imbalances comprising:
means for extracting a plurality of frequency sub-bands from a received wideband signal;
means for compensating each of the plurality of frequency sub-bands to produce an associated plurality of compensated frequency sub-bands, wherein the means for compensating each of the plurality of frequency sub-bands comprises:
means for deriving blind signal separation parameters via a block estimation technique for each of the plurality of frequency sub-bands, wherein the blind signal separation parameters represent unknown imbalance parameters digitally estimated without training signals; and
means for removing an interference component from each of the plurality of frequency sub-bands based on the blind signal separation parameters; and
means for summing the compensated frequency sub-bands to produce a compensated signal.
6. The system of claim 5 , wherein the means for extracting a plurality of frequency sub-bands is a sub-band coder.
7. The system of claim 5 , wherein the means for compensating each of the plurality of frequency sub-bands comprises:
means for applying a frequency dependent algorithm.
8. The system of claim 5 , wherein the means for compensating each of the plurality of frequency sub-bands comprises:
means for applying a frequency independent algorithm.
9. A processor for compensating for frequency dependent imbalances comprising:
a plurality of sub-band coders configured to extract an associated plurality of frequency sub-band from a received wideband signal;
a plurality of compensation algorithm blocks configured to compensate each of the plurality of frequency sub-bands to produce an associated plurality of compensated frequency sub-bands, wherein each compensation algorithm block derives blind signal separation parameters via a block estimation technique for each of the plurality of frequency sub-bands and removes an interference component from each of the plurality of frequency sub-bands based on the blind signal separation parameters, wherein the blind signal separation parameters represent unknown imbalance parameters digitally estimated without training signals; and
an adder configured to sum the compensated frequency sub-bands to produce a compensated signal.
10. The processor of claim 9 , wherein each of the plurality of compensation algorithm blocks is configured to implement a frequency dependent algorithm.
11. The processor of claim 9 , wherein each of the plurality of compensation algorithm blocks is configured to implement a frequency independent algorithm.
12. The method of claim 2 , wherein the sub-band coder is a perfect reconstruction quadrature mirror filter.
13. The system of claim 6 , wherein the sub-band coder is a perfect reconstruction quadrature mirror filter.
14. The processor of claim 9 , wherein each sub-band coder is a perfect reconstruction quadrature mirror filter.
15. The method of claim 1 , wherein a compensated image of the compensated signal is reduced to at least −60 dB with an unaffected noise floor.
16. The method of claim 15 , wherein 8 or fewer subbands are extracted from the received wideband signal.