Adaptive transmit power allocation scheme for V-BLAST system under imperfect channel state information

We propose an adaptive transmit power allocation (ATPA) scheme for vertical Bell laboratories layered space-time (V-BLAST) system in the presence of channel state information (CSI) imperfection. The proposed ATPA scheme is aimed at minimizing the bit error rate (BER). At the transmitter, subjected to the total transmit power constraint, the proposed ATPA scheme is used to allocate proper power for every sub-stream based on imperfect channel state information (I-CSI) and the statistical characteristic of channel estimation errors. At the receiver the modified minimum mean square error (MMSE) detector which takes into account the errors of channel estimation is used to remove the co-antenna interference (CAI) in order to improve BER performance further. Simulation results show that the proposed ATPA algorithm is effective for V-BLAST system under imperfect CSI, the BER performance is better than that with equal power allocation. Moreover, corresponding capacity is approximate equal to that of equal power allocation scheme.