A low-complexity receiver for iterative parallel interference cancellation and decoding in MIMO–OFDM systems

A novel low-complexity iterative receiver for coded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed in this letter. The soft-in soft-out (SISO) detector is simply a parallel interference cancellation (PIC)–maximum ratio combining (MRC) operation. However, system performance would be degraded because of ignoring the existence of the residual interference from other transmit antennas. In our scheme, the log likelihood ratios (LLRs) of encoded bits after channel decoding are multiplied by a constant factor to achieve a performance gain. The constant factor is optimized according to the extrinsic information transfer (EXIT) chart. Simulation results show that the proposed iterative receiver can significantly improve the system performance and converge to the matched filter bound (MFB) with low computational complexity at high signal-to-noise ratios (SNRs).