A High-Performance Double Differential OFDM UWB Receiver

Ultra-wideband (UWB) radio has unique features and is one of the most promising broadband wireless technologies of our times. In this paper, we investigate an OFDM UWB receiver based on single and double differential modulation/demodulation schemes. Since differential detection eliminates the need for channel estimation, it is a highly attractive option where simplicity and robustness of implementation are desired. However, differential detection suffers from a performance gap when compared to coherent detection with perfect channel knowledge at the receiver. We show that this gap is quite small when channel estimation is taken into consideration for the coherent system. Moreover, in the presence of frequency offset, a double- differential system can outperform a coherent system. We also investigate a differential space-time block-coded system based on the Alamouti scheme, and analyze its performance for the UWB environment.