Enhanced cooperative diversity communications

在过去的十年中，对无线数据服务的需求呈爆炸式增长。特别是，从无线语音到无线互联网数据和无线视频的演变导致对无线容量的需求呈指数级增长。然而，提高无线传输速率通常是非常困难的，因为无线信道受到许多伪影的影响，包括衰落，这大大降低了信号的质量。缓解这些挑战的关键方法之一是在发射器和/或接收器上实现多个天线。然而，在许多应用中，例如蜂窝网络、自组织网络和传感器网络，由于终端的尺寸、功率和成本限制，实现多个天线并不总是实际的。为了解决这个问题，一种被称为合作多样性的新技术被提出，最近引起了人们的极大兴趣。合作分集的基本思想是多个单天线终端“合作”以减轻衰落。也就是说，多个终端相互帮助，以便在无线衰落信道上更可靠地发送自己和他人的信号。合作网络的基本性质和性能近年来在许多出版物中得到了研究。然而，仍有一些重要问题有待解决。在本文的研究中，这些问题将得到解决，以增强基于合作分集的无线通信系统。例如，我们将研究合作分集网络中系统资源的最优分配和传输信号分组的有效组合方法等问题。本研究的最终目标是优化合作多样性系统。该研究结果将有助于无线通信公司减少费用，实现利润最大化。由于加拿大有许多无线通信公司，因此这项研究将对加拿大产生直接的经济效益。此外，本研究将为本科生和研究生提供基本的和最新的通信理论，对他们的培训有重要的贡献。

Over the past decade, there has been an explosive growth in demand for wireless data services. In particular, the evolution from wireless voice to wireless internet data and wireless video is causing exponentially increasing demand for wireless capacity. However, it is generally very hard to increase the wireless transmission rates, because the wireless channel suffers from many artifacts including fading, which significantly degrades the quality of the signal. One of the key methods to mitigate such challenges is to implement multiple antennas at the transmitter and/or at the receiver. In many applications, however, such as in cellular, ad hoc, and sensor networks, it is not always practical to implement multiple antennas due to the size, power, and cost limitations of the terminals. Addressing this problem, a new class of technology, called cooperative diversity, was proposed and it has recently drawn a great deal of interest. The basic idea of cooperative diversity is that several single-antenna terminals "cooperate" in order to mitigate the fading. That is, the multiple terminals help one another in order to send their own and other's signals more reliably over wireless fading channels. The basic properties and performance of cooperative networks have recently been studied in many publications. However, there still remain a number of important issues to be solved. In the proposed research, these problems will be solved to enhance the wireless communication systems based on cooperative diversity. For example, we will study the issues on optimum system resource allocation and efficient methods to combine transmitted signal packets in cooperative diversity networks. The final objective of the proposed research is to optimize cooperative diversity systems. The outcomes of this research will enable wireless communications companies to reduce the expenses and help them maximize profits. Since there are many wireless communications companies in Canada, this research will have a direct economic benefit for Canada. Furthermore, this research will significantly contribute to the training of undergraduate and graduate students by providing them with the fundamental and the state-of-the-art theories on communications.