Investigation on the performance of space-time block coded ultrawide band communication systems

摘要

Ultrawide band (UWB) communication systems show many advantages over the conventional narrow band systems. In this paper, three UWB systems at the same transmission efficiency are investigated. The first one is a conventional system with only one transmit antenna (non-STBC). The second one is combined with the space-time block coding (STBC) over one symbol (STBC-1). The third system is combined with the STBC over two symbols (STBC-2), which is in accordance with Almouti's scheme. Both theoretical analysis and simulations show that the STBC-1 system performs the best. In addition, the adoption of the normalized modified Hermite polynomial based orthogonal pulses (NMHP) instead of the Gaussian pulse (GP) to represent the m-ary symbol constellation can increase the data rate and lead to an improvement of the signal to noise ratio (SNR) by about 101og_10M dB at the bit error rate (BER) of 10{sup}(-4) at any symbol constellation for any UWB system. The simulations in both flat-fading channels and frequency-selective channels have confirmed such improvement.