Comparison of ordered successive receivers for space-time transmission

In recent years, a lot of attention has been drawn to the use of multiple antennas at both the transmitter and receiver sides. Such techniques are named here as space-time transmission and noted as STT. By their use of the available space dimension, STT techniques can achieve very high spectral efficiencies at Rayleigh fading channels with rich scattering. In this paper, the use of STT techniques at indoor wireless systems with huge number of antennas is considered. As a low complexity detection algorithm, ordered successive detection based schemes are considered. In this literature, a scheme that is known as V-BLAST has been proposed in the zero forcing criterion (ZF). In a previous work, it has been shown how this scheme can be much improved by the use of a backward iterative detection algorithm. In this paper, an extension of the conventional V-BLAST algorithm to the minimum mean square error (MMSE) criterion is proposed. For the proposed receiver an ordering metric is defined. Then, the effect of ordering on both receivers is discussed. And finally, it is shown how the ordering metric in the MMSE criterion can be simplified.