Optimal power allocation for space-time coded OFDM UWB systems

In the last years, a lot of attention has been devoted to ultra wideband (UWB) systems. The multi-antenna and/or multi-carrier UWB transceiver designs have been well-documented. Compared with great progress at physical layer, the corresponding medium access control (MAC) layer protocol designs are naturally placed on the schedules. In this paper, we focus on the optimal power allocation scheme, which is an integral part of the MAC layer protocol design, for UWB orthogonal frequency-division multiplexing (OFDM) transmissions with space-time code (STC). To maximize the capacity, two kinds of power allocation schemes were presented based on perfect CSI or partial CSI respectively in frequency-selective UWB channels. And our scheme can be easily extended to multi-band system. The analysis and numerical results show good performance.