On Optimization of the V-BLAST Algorithm

Optimum power allocation for the V-BLAST algorithm, which is based on various criteria (average and instantaneous block and total error rates (BLER and TBER)), is considered. Closed-form expressions are derived for high-SNR case in a Rayleigh fading channel. It is demonstrated that, in that case, the optimization "on average" is almost identical to the instantaneous one (while the former requires only the feedback "on average", the latter requires instantaneous feedback and hence is of higher complexity). The BLER and TBER optimization criteria result in the same performance. Power optimization (of un-ordered BLAST) and optimal ordering result in the same performance improvement at high SNR.