A framework for performance analysis of TH-UWB communications

Ultra wide band (UWB) has been proposed in recent years as a suitable transmission technique for various applications in the wireless context and is currently under consideration of standard bodies for e.g. wireless personal area networks. UWB is also inherently indicated for distributed ad-hoc wireless networks and, in particular, for sensor networks. Since operations in shared radio resource environments are crucial to any wireless system, this paper proposes an investigation of the performance of UWB in a multi-user environment with specific interest on the time hopping (TH) alternative. Specifically, the expression of the SINR (signal-to-(noise + interference) ratio) is derived in the presence of a generic family of (multi-level) hopping codes, thus removing the common assumption of independent and identically distributed (i.i.d.) random sequences. The key point is to map a TH-UWB system with multi-level sequences into an equivalent direct sequence (DS) system with binary sequences. Application of the proposed analytical framework includes evaluation of multiple access performance and accurate analysis of synchronization algorithms. While the first step of the analysis assumes an additive white Gaussian noise (AWGN) channel, the model is further extended to incorporate the behaviour of the wireless channel, thus deriving the outage probability in a log-normal shadowed channel, by resorting to the well-known Fenton-Wilkinson approximation.