Linear symbol precoding for low complexity V-BLAST OFDM systems

In this paper we propose a low complexity linear precoded Vertical Bell Labs Layered Space-Time (V-BLAST) orthogonal frequency division multiplexing (OFDM) system based on QR decomposition. A conventional uncoded V-BLAST OFDM system exhibits significant system degradation in a frequency selective fading channel as it does not fully exploit the available frequency diversity. The new preceded scheme exhibits considerable error performance improvement over a conventional V-BLAST OFDM QR system. Simulation results for both linear and maximum likelihood estimators indicate a trade off between the allowable complexity against the achievable system performance. An extended analysis for error propagation across the different layers in the case of V-BLAST OFDM is also presented