O33-based linear decorrelating detector for asynchronous UWB systems over multipath fading channels

In this paper, a convenient signaling scheme, termed orthogonal on–off Ultra wideband (UWB) (O33UWB), along with a simple one-shot linear decorrelating detector (LDD) and a Rake bank, is proposed. This scheme is useful for conducing multi-user detection because temporally adjacent bits in receiver signals from different users are decoupled using on–off signaling. This mechanism also leads to one-shot detection that overcomes the main disadvantage, long detection delay, of the conventional LDD. In addition, the data rate is maintained, with no increases in the transmission rate, by adopting an orthogonal structure. In this paper, we study the system performance over a flat fading channel. Four types of channel models, including Rayleigh fading, Nakagami-mm fading, Rician fading, and Lognormal fading, are considered. Since multipath fading still significantly degrades UWB system performance, the Rake bank is included to recover multipath diversity gain. Numerical analysis and simulation results show that the O33UWB LDD receiver still offers a good near-far resistant property over fading channels compared to the conventional UWB receiver.