A New Stream Power Allocation Method for SU Beamforming in BICM MIMO-OFDM Systems for IEEE WLAN

In this paper, we propose a new stream power allocation method for single-user beamforming for BICM MIMO-OFDM systems. To this end, we first employ a mean mutual information per bit (MMIB) for power allocation problem to accurately estimate the error rate performance. Also, a simple stream SINR for maximum likelihood detection is derived to calculate the MMIB. Then, the optimal power allocation with a diagonal matrix is derived from the approximated function of the MMIB. Also, we extend the diagonal matrix power allocation to a rotational matrix power allocation, which can provide more diversity gain thanks to combined sub-channel process. Finally, we propose an adaptive power allocation algorithm between the diagonal matrix and the rotational matrix, since the rotation matrix incurs inter-stream interference due to off-diagonal terms so that there is a performance trade-off. From the link level simulation on IEEE WLAN, we verify that our proposed stream power allocation method is effective to improve the packet error rate performance.