Báo cáo hóa học: Research Article Particle Swarm Optimization Based Noncoherent Detector for Ultra-Wideband Radio in Intensive Multipath Environments

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Báo cáo hóa học: " Research Article Particle Swarm Optimization Based Noncoherent Detector for Ultra-Wideband Radio in Intensive Multipath Environments"Hindawi Publishing CorporationEURASIP Journal on Advances in Signal ProcessingVolume 2011, Article ID 341836, 14 pagesdoi:10.1155/2011/341836Research ArticleParticle Swarm Optimization Based Noncoherent Detector forUltra-Wideband Radio in Intensive Multipath Environments Bin Li, Zheng Zhou, Weixia Zou, and Wanxin Gao Key Lab of Universal Wireless Communications, MOE, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications (BUPT), P.O. Box 96, Xi Tu Cheng Road, Beijing 100876, China Correspondence should be addressed to Bin Li, stonebupt@gmail.com Received 11 June 2010; Revised 13 November 2010; Accepted 17 January 2011 Academic Editor: Yannis Kopsinis Copyright © 2011 Bin Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Given the dense multipath propagation in typical ultra-wideband channels, traditional coherent receivers may become computationally complex and impractical. Recently, noncoherent UWB architectures have been motivated with simple implementations. Nevertheless, the rudimentary statistical assumption and practical information uncertainty inevitably results in a hardly optimistic receiving performance. Inspired by the nature processes, in this paper we suggest a noncoherent UWB demodulator based on the particle swarm intelligence which can be realized in two steps. Firstly, a characteristic spectrum is developed from the received samples. From a novel pattern recognition perspective, four distinguishing features are extracted from this characteristic waveform to thoroughly reveal the discriminant properties of UWB multipath signals and channel noise. Subsequently, this established multidimensional feature space is compressed to a two-dimension plane by the optimal features combination technique, and UWB signal detection is consequently formulated to assign these pattern points into two classes at the minimum errors criterion. The optimal combination coefficients and the decision bound are then numerically derived by using the particle swarm optimization. Our biological noncoherent UWB receiver is independent of any explicit channel parameters, and hence is essentially robust to noise uncertainty. Numerical simulations further validate the advantages of our algorithm over the other noncoherent techniques.1. Introduction health monitoring [7], due to its simple implementations and extremely low radiation. Impulse radio (IR) is one of physical proposal forThe fast growing interest in ultra-wideband (UWB) has UWB communications, in which the information bit isbeen stimulated by the attractive features including low directly coded into a set of short-duration baseband pulsesprobability of detection (LPD), low power consumption [1, 8]. If the principle of UWB-IR is taken into account,and low-scomplexity baseband operations [1, 2]. Due to its without the complicated radio frequency (RF) front-end, thepotential that provides an extremely high data rates even low-complexity transmitter seems to be feasible generally.surpassing 1 Gbps, UWB has long been considered as a Nevertheless, owing to the enormous bandwidth of emissionpromising candidate for high-speed transmissions in wireless pulses which even may be up to several gigahertz (GHz),personal area networks (WPANs) [3, 4], mainly for the signal processing for UWB receivers has been remained asonline broadband multimedia stream services in short range formidable challenges in the presence of the highly dis-applications (10–15 m). Meanwhile, with its outstanding persive propagations [9–11]. So, those traditionally derivedcapability of positioning and material penetrating (e.g., the optimal coherent receivers may be not applicable for UWBfoliage and walls), UWB has intensive military applications, systems in three considerations [12]. First, synchronizationsuch as the high-resolution ground penetrating radars in coherent receivers must be accomplished at the scale(GPRs), through-wall imaging, and precise navigation [5, 6]. of subnanosecond duration, which requires sophisticatedMost recently, the emerging body area networks (BANs) algorithm and lo ...