Iterative soft interference cancellation for multiple antenna systems

This paper proposes an iterative soft interference cancellation scheme for a multiple antenna system. The proposed scheme is derived from the maximum a posteriori (MAP) criterion. At each iteration, the a posteriori probability is obtained by cancelling out the previous soft symbols, new soft symbols are calculated based on the a posteriori probability, and the total interference-plus-noise power is dynamically updated to account for the uncertainty in the soft symbols. The computational cost of the proposed algorithm grows linearly with the number of antennas while that of the optimum MAP detector grows exponentially. Simulations results show that an SNR gain of about 3 to 5 dB can be obtained by the proposed soft cancellation scheme