MIMO turbo receiver with new probability data association soft interference cancellation

We propose a multiple-input multiple-output (MIMO) turbo receiver with a new soft-in soft-out (SISO) probability data association (PDA) soft interference cancellation (SIC) detector. Within this turbo receiver architecture, SIC is performed by subtracting the soft estimated values of interfering signals from the received vector. Based on Gaussian forcing of transmitted symbols, the likelihood function associated with the received vector after SIC is calculated and then extrinsic bit likelihood ratio (BLR) or log-likelihood ratio (LLR) is obtained and fed into the SISO channel decoder as a priori information. This process is different from conventional processing of a PDA type detector, in which a posteriori symbol probability is calculated, but the a posteriori probability cannot be delivered into the channel decoder directly in the turbo receiver. Simulation results show that this PDA SIC MIMO turbo receiver has exactly the same performance as the minimum mean square error (MMSE) SIC MIMO turbo receiver, which is widely used, but the computation of the PDA SIC detector is more efficient and numerically stable.