CAREER: Signal Processing Research in Ultra Wideband Communications

随着美国联邦通信委员会（FCC）于2002年发布了超宽带（UWB）信号频谱掩码，UWB已经成为一项令人兴奋的技术，商用无线通信和局域网的“时代已经到来”。超宽带通过类脉冲无线电（IR）波形传输信息，具有独特的吸引力：低功率密度无载波传输、充足的多径分集、低复杂性基带收发器、容量巨大增加的潜力，以及覆盖现有射频系统的能力。然而，为了实现红外的潜力，UWB研究和开发必须应对艰巨的挑战，包括：对超短脉冲接收时间的高灵敏度，明显频率选择性的衰落传播效应的缓解，解码高性能多址协议的低复杂性限制，以及由最小化UWB通信器之间干扰的愿望所施加的严格功率限制，以及共存的RF系统。本研究解决了UWB通信中出现的及时信号处理问题，重点关注：(1)开发最优和低复杂度的次最优定时历元估计器以及评估其性能的指标，以及对UWB系统误码率和吞吐量的影响。(2) UWB多址协议中基于低复杂度近最优软判决的多用户检测器和多通道均衡器的推导和收敛性分析。(3)研究覆盖问题、调制方案、编码、解码和干扰抑制算法，以实现UWB频谱掩码兼容性，并与其他无线业务共存。(4)部署多收发天线，提高低复杂度解码、时序估计和多用户检测性能。这项研究的结果将影响即将到来的多址超宽带无线系统的基本理论、设计和部署。

Abstract 0238174Zhi Tian Michigan Tech Univ. With the recent release of the Ultra Wideband (UWB) signal spectral mask by the Federal Communications Commission (FCC) in 2002, UWB has emerged as an exciting technology whose ``time has come'' for commercial wireless communications, and local area networking. Conveying information over Impulse-like Radio (IR) waveforms, UWB comes with uniquely attractive features: low-power-density carrier-freetransmissions, ample multipath diversity, low-complexity baseband transceivers, a potential for huge increase in capacity, and the capability to overlay existing RF systems. However, to bring the potencyof IR to fruition, UWB research and development has to cope with formidable challenges that include: high sensitivity to timing the reception of ultra-short pulses, mitigation of fading propagation effects with pronounced frequency-selectivity, low-complexity constraints in decoding high-performance multiple access protocols, and the strict power limitations imposed by the desire to minimize interference between UWB communicators, and co-existing RF systems. This research addresses timely signal processing issues arising in UWB communications, with focuses on: (1) The development of optimal and low-complexity sub-optimal timing epoch estimators along with metrics to assess their performance, and influence on the bit error probability and throughput of UWB systems. (2) The derivation and convergence analysis of low-complexity near-optimal soft-decision based multiuser detectors, and multi-channel equalizers for UWB multiple access protocols. (3) The investigation of overlay issues, modulation schemes, coding, decoding, and interference suppression algorithms to enable UWB spectral mask compatibility, and co-existence with other wireless services. (4) The deployment of multiple transmit-receive antennae to improve performance of low-complexity decoding, timing estimation, and multiuser detection. The outcome of this research will impact the basic theory, design, and deployment of forthcoming multiple access UWB wireless systems.