Channel Residual Energy based combine estimation of imperfections of receiver in MIMO-OFDM system

The performance of Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems is seriously affected by various imperfections at receiver such as In-phase/Quadrature-phase (I/Q) imbalance, Carrier Frequency Offset (CFO) and DC offset. The proper estimation of theses imperfections at the receiver lead to increase the Bit Error Rate (BER) performance of the system. The training sequence based estimation is proposed in this paper for combine correction of I/Q imbalance and CFO estimation. Channel Residual Energy (CRE) is used for estimation. The performance of the proposed system is based on Crammer-Rao bound. Simulation results shows that our proposed method gives improved results over IQ-CFO-FD method for joint estimation of (I/Q) imbalance, (CFO) and channel response. Also we show that as number of transmit antennas increases at transmitter side then mean square error is reduced, this leads the further reduction in these imperfections in MIMO-OFDM systems.