Power Allocation for Distributed Transmit Diversity with Feedback Loop Delay

We study two power allocation (PA) schemes for distributed transmit diversity systems. We first derive the performance of the instantaneous channel gain feedback-based PA (ICG-PA) scheme in the presence of channel variation during feedback delay. We then study channel gain variance feedback-based PA (CGV-PA) to mitigate the performance degradation of ICG-PA caused by feedback delay. Finally, we derive design rules for optimum CGV-PA from a compact and accurate performance expression derived.