A Systematic Luby Transform Coded V-BLAST System

Abstract

Systematic Luby Transform (SLT) codes have shown good performance for single antenna aided systems for transmission over AWGN and uncorrelated Rayleigh fading channels. For the sake of improving both the Bit Error Ratio (BER) performance and the diversity gain of Vertical Bell Laboratories Layered Space Time (V-BLAST) schemes, in this paper we propose a SLT coded V-BLAST system having four transmit and four receive antennas. As a benefit of iteratively exchanging the Log-Likelihood Ratios (LLRs) between the QPSK demapper and the SLT decoder of each antenna-specific stream of the V-BLAST system, the system exhibits an infinitesimally low BER for E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> values in excess of 6.5 dB, when using an interleaver length of L = 1, 200 bits. Additionally, the SLT coded system provides an E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> gain of 5 dB at a BER of 10 6 over its benchmark scheme employing iterative extrinsic information exchange between a Recursive Systematic Convolution (RSC) code and a unity-rate code, having an interleaver length of L= 1,200 bits.