Performance Evaluation in the Presence of Timing Jitter using a Novel Pulse Design Based on Hermite Functions for UWB Communications

摘要

Ultra-wideband (UWB) technology, as a possible standard for wireless personal area network (WPAN) solutions, has attracted a growing interest in research institutions and industry. The Federal Communications Commission (FCC) has regulated that UWB systems must operate with their -10 (-20)dB bandwidth of the spectrum within the frequency 3.1-10.6GHz for indoor (outdoor) communications to ensure its viable coexistence with other systems. Many pulse shapes have been proposed for UWB impulse radio systems including the Gaussian monocycles [1], modified Hermite polynomial (HP) based pulses [2] and prolate spheroidal functions (PS) based pulses [3]. Unfortunately, the widely adopted Gaussian monocycle exhibits a poor fit to the FCC spectral mask and thus is not suitable for practical usage. Pulses proposed in [3] generated from different eigenvectors are mutually orthogonal, and conform to the FCC mask. However, they require a high sampling rate (64GHz) that could lead to implementation difficulties. Recently, a set of orthogonal pulses based on Modified Hermite polynomial (MHP) was proposed in [3], but we note that the pulses of even orders have DC components and several operations are required for HP pulses to meet the FCC masks, which greatly increase the complexity of the implementation. In this paper, a novel pulse shaping algorithm based on Hermite polynomials (NMHPs) is presented in Section II. The proposed pulse has very different properties between the MHPs in [2] despite of the apparent similarity. The BER performances of NMHPs and Scholtz's monocycle in the presence of timing jitter are analyzed in Section III and simulated in Section IV for both single-link and the multi-access UWB systems. Finally, conclusions are presented in Section V.