Modelling and Optimising Cognitive Radio Networks

在过去十年中，无线通信服务出现了前所未有的增长，这导致了频谱带的严重稀缺，并对可用的无线电频谱带施加了越来越大的压力。然而，许多研究人员报告的实际频率使用测量表明，一些许可的无线电频谱利用率极低。传统的静态频谱分配方法可以有效地减少不同无线业务之间的干扰，但会导致严重的频谱短缺和低的授权频谱利用率。频谱共享是缓解这一困境的潜在解决方案。为了响应谷歌、摩托罗拉、微软、Earthlink和戴尔等科技公司的要求，开放未使用的频谱（称为“白色空间”）用于未经许可的使用，美国联邦通信委员会（FCC）发布了一份拟议规则制定通知，推进认知无线电（CR）技术作为实现频谱共享的候选技术。认知无线电是一种无线电系统，它通过持续感知频谱来识别频谱白色空间，然后在授权用户的主用户不活动时在频谱中工作。为了使CR节点在不影响授权用户的情况下接入某些授权频谱，CR用户必须准确地检测未使用的频谱，选择最佳可用信道进行接入，并在CR用户之间协调对该信道的接入。在许可频谱中操作的CR用户必须保持感知频谱，并且一旦检测到主用户就立即释放信道。这些要求使得CR网络设计极具挑战性。本文的研究目标是研究认知无线电网络的建模和设计，以提高频谱检测和优化频谱共享。该研究的完成将大大提高授权频段的利用率，缓解频谱短缺的压力。主要发现将获得专利并授权给工业。此外，该项目将通过培训更多的高素质人员（HQF）帮助建设加拿大的研究能力。

The last decade has seen unprecedented growth in wireless communication services, which has consequently resulted in severe scarcity of spectrum bands and imposed increasing pressure on the available radio spectrum bands. However, actual frequency usage measurements reported by many researchers indicate some licensed radio spectrums are extremely underutilized. The conventional static spectrum assignment is effective to reduce interference between different wireless services but results in severe spectrum scarcity and low utilization of licensed spectrum. Spectrum sharing is a potential solution to alleviate this dilemma. In response to request from technology companies like Google, Motorola, Microsoft, Earthlink and Dell, to open the unused spectrum known as 'white space' for unlicensed use, the American Federal Communications Commission (FCC) has issued a Notice of Proposed Rule Making advancing cognitive radio (CR) technology as a candidate to implement spectrum sharing. Cognitive radios are radio systems that continuously sense spectrum to identify spectrum white space, and then operate in spectrums whenever the licensed users 'primary users' are not active. In order for a CR node to access certain licensed spectrum without affecting the licensed users, the CR user must accurately detect unused spectrum, select the best available channel to access, and coordinate access to this channel among CR users. The CR users that are operating in licensed spectrum must keep sensing the spectrum and immediately release the channel once a primary user is detected. These requirements make CR network design extremely challenging. The goal of the proposed research is to study CR network modeling and design in order to improve spectrum detection and optimize spectrum sharing. Completion of the proposed research will greatly improve the utilization of licensed spectrum bands and alleviate the pressing spectrum scarcity. The main findings will be patented and licensed to industries. Furthermore, this project will help building Canada research capacity by training additional Highly Qualified Personnel (HQF).