Multidimensional Modulation and Coding for Ultra-Wideband (UWB) Low-power Wireless Communications

该项目的范围是为使用超宽带（UWB）技术的短距离、高速率、低功耗无线网络开发多维信号设计和编码方案。本课题的主要成果如下：(1)在考虑UWB无线通信峰值发射限制的情况下，明确了UWB系统中信道容量与占用带宽的关系。(2)提出了基于直接序列扩频调制的超宽带通信新信令方案；其中包括混合直接序列/跳时（DS/TH）超宽带，直接序列多波段超宽带，混合DS/TH多波段超宽带。同时，提出了一种基于ds -多波段超宽带信令的干扰抑制技术，以保护现有的无线通信系统。通过计算机仿真对该方法在多波段超宽带系统中的应用效果进行了评价。在超宽带无线通信中，并行组合超宽带信令是一种在发射限制下的多维信令和编码。(3)建立了DS-UWB通信系统性能评价的理论框架。采用简化改进高斯近似法（SIGA）和特征函数法（CF）进行多址干扰建模。实验结果表明，该方法在各种脉冲形状和衰落信道环境下都有较好的性能。通过计算机仿真验证了理论结果。(4)针对多径衰落信道环境，开发了DS-UWB无线通信系统的Rake接收。讨论了结合能量较大的若干路径的选择性Rake接收和结合较早到来的若干路径的部分Rake接收。讨论了定时抖动、脉冲间干扰和量化误差对Rake接收误码率性能的影响。提出了最佳Rake接收的概念，提出了分数间隔Rake接收以实现UWB无线通信中的次优Rake接收。少

Scope of this project is developing multidimensional signal design and coding scheme for short-range, high-rate, low-power wireless network using ultra-wideband (UWB) technology. Major achievement of this project is as follows :(1) The relationship between channel capacity and occupied bandwidth is clarified in UWB systems with considering peak emission limit in UWB wireless communications.(2) Novel signaling schemes for UWB communications are proposed based on direct sequence spread spectrum modulation ; which include hybrid direct-sequence/time-hopping (DS/TH) UWB, direct-sequence multiband UWB, hybrid DS/TH multiband UWB. Also, an interference mitigation technique based on DS-multiband UWB signaling is proposed for protecting incumbent wireless communication systems. Effect of this proposed method in DS multiband UWB systems is evaluated by computer simulation. Parallel combinatorial UWB signaling is proposed as a multidimensional signaling and coding under the emission limit in UWB … More wireless communications.(3) Theoretical framework for performance evaluation is developed in DS-UWB communication systems. Simplified improved Gaussian approximation (SIGA) method and characteristic function (CF) method are applied for modeling of multiple access interference. It is found that the CF method shows accurate performance with various pulse shape and fading channel environment. Theoretical results are validated by computer simulation.(4) Rake reception for DS-UWB wireless communication systems is developed to combat multipath fading channel environment. Selective Rake reception which combines several paths having larger energy, and partial Rake reception which combines several paths coming earlier, are discussed. Impact of timing jitter, inter-pulse interference, and quantization error to the error rate performance in the Rake reception is discussed. Concept of optimum Rake reception is proposed fractionally spaced Rake reception is proposed to achieve the suboptimum Rake reception in UWB wireless communications. Less