Wanchen Hu

In a multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) system, the conventional singular value decomposition (SVD) based precoders may destroy the smoothness of the effective channel, - i.e., the concatenation of the precoders and the channel - in the frequency domain, causing difficulties to the channel estimation. This letter proposes a phase-rotated SVD (PR-SVD) via exploiting the phase non-uniqueness of SVD to make the effective channel as smooth as possible in the frequency domain to facilitate the channel estimation. The simulation results verify that the proposed PR-SVD based precoding method can improve the channel estimation and consequently can significantly outperform the state-of-the-art method in bit error rate (BER).

This letter proposes a multi-input multi-output (MIMO) transceiver design termed channel bi-diagonalization (CBD), whose precoder and equalizer bi-diagonalize the channel matrix. By representing the bidiagonal MIMO channel with a trellis diagram, we can apply the Viterbi algorithm for the maximum likelihood (ML) detection and decoding, or the BCJR algorithm for the maximum a posteriori (MAP) detection and decoding, which drastically simplifies the optimal MIMO communications. Simulation results verify the superior performance of the proposed CBD scheme.