Time-frequency multiplex estimator design of joint Tx IQ imbalance, CFO, channel estimation, and compensation for OFDM systems

A low complexity time-frequency multiplex estimator and low complexity equalizer transceiver design is proposed to combat the RF impairment problems for the zero-IF transceiver of orthogonal frequency-division multiplexing (OFDM) systems. Moreover, the proposed preamble can estimate and compensate the transmitter (Tx) in-phase and quadrature-phase (IQ) imbalance, carrier frequency offset (CFO) and channel impulse response parameters. There are two parts in the proposed system. Firstly, all parameters of impairments are estimated by the proposed time-frequency multiplex estimator design. Secondly, the estimated parameters are used to equalize the above problems and detect the transmitted signal with low complexity advantage. Simulation results confirm that the proposed estimator can provide reliable performance over the severe IQ imbalance, CFO, and multipath fading channel environment.