on the snr penalty for antenna subset diversity
In this paper, we derive the asymptotic symbol error probability (SEP) of antenna subset diversity (SSD), where the signals from a subset of antenna elements are selected and combined in the presence of channel estimation error. The analysis is valid for arbitrary two-dimensional signaling constellations. We investigate the asymptotic SNR penalty, or performance loss between this system and an ideal system, caused by estimation error. We also compare this SNR penalty to that of a SSD system operating with perfect selection, but imperfect combining. We consider independent identically distributed (i.i.d.) Rayleigh fading channels and use an estimator structure based on the maximum likelihood (ML) estimate which arises naturally as the sample mean of N p pilot symbols. In both cases our analytical results show that the practical ML channel estimator still preserves the diversity order of an ideal SSD system with N d branches.
antenna subset diversity practical channel estimation incomplete channel state information