Analytical BER Analysis of the V-BLAST in a Rayleigh Fading Channel

The BLAST algorithm is simple and, hence, popular solution for a signal processing at the MIMO receiver. In this paper, we present a closed-form analytical analysis of the V-BLAST without optimal ordering. A result on the zero-forcing maximum ratio combining weights at each detection step is derived to obtain a number of results: independence of noise, distribution of signal to noise ratio and block or bit error rates. We present a detailed analytical analysis and closed-form expressions for instantaneous and average BER at each detection step, which account for the error propagation and hold true for any modulation format and take simple form in some cases (BPSK). Asymptotic form, for large average SNR, of these expressions is especially simple; the effect of the error propagation in this mode is to increase the total average BER by about 20, which is not catastrophic at all. It is demonstrated that the conventional V-BLAST and QR-decomposition based V-BLAST are essentially identical and have the same performance. Extensive Monte-Carlo simulations validate the analytical results and conclusions.