An Improved Detection Technique For Receiver Oriented MIMO-OFDM Systems

In rich scattering environments, layered Space Time architectures like the BLAST (Bell Labs Layered Space Time) system may exploit the capacity advantage of multiple antenna systems. In case of a broadband wireless transmission, the channel undergoes frequency selective fading which necessitates the receiver to have a multi tap equalizer. This can be avoided by employing an OFDM (Orthogonal Frequency Division Multiplexing) scheme which would also increase the spectral efficiency of the system. In this paper, we present an efficient algorithm for detecting layered architectures as applied to an OFDM system. It utilizes a QR decomposition of the channel matrix for each subcarrier and a successive interference cancellation (SIC) structure. The performance of the above method is further improved by likelihood weighting of the detected symbols based on the estimated channel coefficients and soft decision Viterbi decoding.