Abstract
In this paper, a low-complexity near-optimal detector for 8-layer MIMO systems is proposed. The detector employs subspace detection schemes, which decompose a spacially multiplexed MIMO channel into multiple decoupled streams to be detected separately. Several existing subspace detection algorithms are studied, all of which require a significant overhead for channel matrix decomposition. We propose computationally efficient schemes based on special layer ordering, followed by permutation-robust QR Decomposition (PR-QRD) using the modified Gram-Schmidt orthogonalization procedure, and elementary matrix operations. A hardware architecture is proposed, which allows building an 8-layer detector from 4-layer and 2-layer constituent detector blocks. Simulations demonstrate that using the proposed scheme, the QRD overhead is reduced by 30%, without incurring any performance degradation.