Timing Recovery for Ultra Wideband Systems

This paper examines the problems of symbol timing estimation and timing recovery for ultra wideband impulse radio signals. Two different approaches based onthe maximum likelihood technique are investigated. The first approach is based on derivative matched filter and the second one takes advantage of the early-late technique. Furthermore, two non-coherent timing recovery circuits are proposed and discussed. The first circuit is a digital delay-locked loop (DDLL) and the second circuit is based on early-late technique. Finally, performance analysis of the proposed techniques for IEEE 802.15.3a channel models in terms of the minimum squared error (MSE) is provided

A Novel DS-UWB Pulses Design Using Genetic Algorithm

[[abstract]]This paper proposes a new pulse design method to improve spectrum utilization rate and reduce the outage probability in ultra wide band (UWB) system. Several third derivative Gaussian waveforms are employed to generate the pulse based on the bandwidth constraint set by the US Federal Communications Commission (FCC) mask. The genetic algorithm (GA) is used to find the optimal pulse parameter. This method is an easy way to achieve in practical circuit implementation compared to one pulse generator, since COMS circuit is hard to produce one pulse with short duration and complex pulse shape. Comparisons with the traditional Gaussian pulse, the synthesis pulse by GA not only satisfy the FCC emission mask but also have high spectrum utilization rate. Simulation results show that the performances in indoor UWB system using the synthesis pulse by GA is better than that using traditional Gaussian pulse. Numerical results show that the synthesis pulse by GA is higher 30 percent of spectrum utilization rate and lower 65 percent of outage probability for the same transmission power, as well as lower 21 percent of outage probability for fixed signal-to-noise ratio (SNR)at the receiver comparing with traditional Gaussian pulse. This proposed method not only use in indoor UWB system but also can extend to different communication system just changing the system object function.[[conferencetype]]國際[[conferencedate]]20090403~20090405[[iscallforpapers]]Y[[conferencelocation]]Kuala Lumpar, Malaysi

Random sampling of signals concentrated on compact set in localized reproducing kernel subspace of Lp(Rn)L^p({\mathbb R}^n)

The paper is devoted to studying the stability of random sampling in a localized reproducing kernel space. We show that if the sampling set on $\Omega$ (compact) discretizes the integral norm of simple functions up to a given error, then the sampling set is stable for the set of functions concentrated on $\Omega$. Moreover, we prove with an overwhelming probability that ${\mathcal O}(\mu(\Omega)(\log \mu(\Omega))^3)$ many random points uniformly distributed over $\Omega$ yield a stable set of sampling for functions concentrated on $\Omega$.Comment: 17 page

Novel UWB pulse shaping using prolate spheroidal wave functions

In this paper novel prolate spheroidal wave functions are proposed as pulse shapes for use in impulse radio (ultra-wideband) communications. These classes of functions yields orthogonal pulses and have a constant pulse width regardless of the pulse order. This is an important property since it eliminates inter-symbol interference. An M-ary communications system is considered that employs these pulses, and the generation of these pulses using the eigenfunction form of a self-adjoint operator is proposed. It is also shown that these pulses are suitable for use in pulse position modulation (PPM) ultra wideband (UWB) communication systems