Reduced complexity group sphere decoder joint with interference cancellation for multistream MIMO

In this paper, we propose a novel antenna-wise group sphere decoder (GSD) joint with interference cancellation for multistream MIMO. The multiple streams are partitioned and ordered into subgroups based on the cross-correlation between channel impulse responses. The signals at each subgroup are jointly detected by the sphere decoder from stronger to weaker subgroup based on the received signal with interference suppression. The justification is that the stronger signals can be detected more reliably and induce stronger interference to others. By partitioning the multistream into subgroups, the GSD has the much lower complexity than the conventional sphere decoder over the whole streams. Numerical results showed that the proposed scheme considerably outperforms the conventional OSIC (ordered successive interference cancellation), the original detection algorithm for VBLAST, and is slightly worse than the SD over the whole multiple streams.