Pairwise joint probability propagation in BICM-ID

Abstract

International audienceThe iterative decoding of BICM is analyzed from an optimization point of view. The objective function in standard iterative decoding proceeds from a coarse approximation of the optimal Maximum Likelihood Decoding. This approximation is suitable when large block of data are processed but may be critical for short blocks. In this contribution, it is proved that refined approximations can be obtained by propagating extrinsics on groups of bits instead of single bits. The particular case of pairwise joint probability propagation is investigated. The computational complexity is similar to the standard iterative decoding. Simulations show the favorable behaviour of the proposed method with both AWGN and fading channels