Methods and apparatuses for in-phase and quadrature-phase imbalance compensation
At least one example embodiments discloses a method of compensating for in-phase and quadrature (IQ) imbalance in a base station. The method includes generating, at the base station, compensation filter weights based on a plurality of IQ imbalanced training signals, the generating including, determining the compensation filter weights based on the plurality of imbalanced training signals in a frequency domain. The method further includes filtering based on the compensation filter weights.
1. A method of compensating for in-phase and quadrature (IQ) imbalance in a base station, the method comprising:
generating input signals for an analog circuit of the base station, a plurality of IQ imbalanced training signals being outputs of the analog circuit and based on the input signals, the generating input signals includes,
determining Discrete Fourier Transforms (DFT) of real signals of the input signals;
generating, at the base station, compensation filter weights based on the plurality of IQ imbalanced training signals, the generating compensation filter weights including,
determining the compensation filter weights based on the plurality of imbalanced training signals in a frequency domain; and
filtering based on the compensation filter weights.
2. The method of claim 1 , wherein the generating input signals includes generating continuous wave tone signals as the input signals.
3. The method of claim 1 , wherein the generating input signals includes generating wideband signals as the input signals.
4. The method of claim 1 , the filtering includes,
receiving a signal from a remote device, and
filtering the signal to reduce an IQ imbalance of the signal.
5. The method of claim 4 , wherein the filtering includes,
outputting a compensated output signal, the compensated output signal being based on a DFT of the received signal.
6. The method of claim 5 , wherein the compensated output signal is two times the DFT of the real signal of the received signal.
7. A method of compensating for in-phase and quadrature (IQ) imbalance in a base station, the method comprising:
generating, at the base station, compensation filter weights based on the plurality of IQ imbalanced training signals, the generating compensation filter weights including,
determining the compensation filter weights based on the plurality of imbalanced training signals in a frequency domain, the determining the compensation filter weights includes,
determining DFTs of the IQ imbalanced training signals; and filtering based on the compensation filter weights.
8. The method of claim 7 , wherein the determining the compensation filter weights includes,
determining the compensation filter weights based on a least-squares fit of the DFTs of the IQ imbalanced training signals.
9. The method of claim 7 , wherein, each IQ imbalanced training signal has a direct-path signal and an image signal, the determining the DFTs of the IQ imbalance training signals includes,
determining the DFTs of the direct-path signals and image-path signals of the IQ imbalanced training signals.
10. The method of claim 9 , further comprising:
filtering at least one of the plurality of IQ imbalanced signals using the compensation, filter weights.
11. The method of claim 10 , wherein the filtering includes,
digitally filtering at least one of the plurality of IQ imbalanced signals using the compensation filter weights.
12. A user equipment (UE) configured to receive a compensated signal from a base station, the signal being compensated based on Discrete Fourier Transforms of real signals of input signals for an analog circuit of the base station, a plurality of IQ imbalanced training signals being outputs of the analog circuit, the signal being compensated being further based on the plurality of IQ imbalanced training signals and compensation filter weights based on the plurality of imbalanced training signals in a frequency domain.