On Generating Soft Outputs for Lattice-Reduction-Aided MIMO Detection

Lattice reduction (LR) aided MIMO detection has been shown to provide near-optimal hard outputs. However soft outputs are required in practical systems to fully exploit gains from forward error correction. Due to the non-linear nature of LR aided MIMO detection, generating soft information on the estimates it provides is not trivial. Consequently this problem has not been treated much in the literature. In this paper we present two related algorithms for computing soft outputs on estimates of LR-aided MIMO detection. It is shown through computer simulations that the proposed soft output generation algorithms allow LR-aided MIMO detection to achieve near- optimal performance for coded systems.