A data-aided iterative UWB receiver with LDPC

Abstract

Research on Ultra-Wideband (UWB) signal detec- tion has mainly concentrated on Rake receivers and general- izations of pilot-assisted receivers. Rake receivers are severely limited by a low energy capture for a moderate number of fingers, whereas pilot-assisted receivers require a prohibitively large number of pilots at low SNR to limit the effect of a noisy correlation template. Probability of error expressions for these two receivers are derived. The effect of channel estimation on the Rake receiver, which is usually neglected in the literature, is taken into account. Then, an iterative data-aided pilot-assisted receiver employing low density parity check coding (LDPC) is proposed. This receiver captures the entire received energy, while significantly reducing the required training overhead. The introduction of the LDPC code allows for improved template estimation in the iterative receiver. Moreover, because of impulse- based UWB's low duty cycle, coding can be introduced without severely reducing the system data rate. The proposed approach exploits the synergy between coding, improved channel estimation and large UWB bandwidth to yield large performance gains. It is shown that such a detection strategy potentially outperforms traditional receiver structures.