High-performance compensation scheme for frequency-dependent IQ imbalances in OFDM transmitter and receiver

An efficient compensation scheme combining a time-domain Gaussian elimination (GE) channel estimator and a frequency-domain GE equalizer is proposed for orthogonal frequency division multiplexing (OFDM) systems with frequency-dependent in-phase and quadrature-phase (IQ) imbalances at both transmitter and receiver. Compared with the traditional least square and least mean square compensation schemes, the proposed compensation scheme achieves the same bit error rate as the ideal IQ branches by using only two training OFDM symbols instead of about 20 OFDM symbols.