An Improved Soft Decision Based MIMO Detection Using Lattice Reduction

This paper presents a performance analysis of soft decision based Lattice Reduction (LR) aided Schnorr-Euchner (SE) multiple-input-multiple-output (MIMO) detection algorithm with that of a hard one. We develop an advanced soft decoding scheme, for 4×4 MIMO with different modulation schemes and it provides 1.3 to 1.5 dB improvement compared to the LR-aided hard decision based detection method. The optimum parameters for K and saturation limit are further derived using extensive simulation. In the conventional K-best algorithm limiting the LLR values is not beneficiary in reducing the optimum size of candidate list, whereas applying the saturation limit on the LLR values in LR-aided algorithm will result in more than 8x reduction in list size as well as in the complexity of detector and LLR calculation unit.