VLSI implementation issues of lattice decoders for MIMO systems

Lattice decoders for MIMO systems, including the sphere decoder (SD) and the Schnorr-Euchner (SE) decoder, have been shown to approach the performance of Maximum-likelihood decoder with low complexity. There are three kinds of lattice decoder, sequential SD, K-best SD and sequential SE, which are popular in the literature. As a modification to the K-best SD, a lower complexity K-best SE is proposed in this paper. Furthermore, the K-best SE is shown to be a more suitable choice for VLSI implementation than the other decoders due to its low complexity in fixed-point implementation.