Efficient resource allocation schemes for cognitive radio networks: agile spectrum sharing and enabling technologies

近年来，随着无线用户数量的不断增长，无线应用变得越来越重要。然而，无线电频谱是一种稀缺的自然资源；而且它的大部分都分配给了身份明确的授权用户。一般情况下，持牌用户不愿与其他不认识的用户分享他们的频谱，而且大部分持牌频谱没有得到充分利用。认知无线电（CR）技术（基于软件无线电）为解决频谱短缺和频谱利用不足问题提供了一种实用的方法。这是通过实现动态频谱接入的概念来实现的，使未授权的CR用户可以动态访问已授权的频谱，而不会对已授权用户造成有害干扰。本研究计划的重点是开发原创和创新的高效资源分配方案，以将CR技术集成到新兴的无线网络技术中。首先，我们将研究协同通信下运行的CR节点——通过利用邻居节点中可用的天线构建虚拟多天线系统。这种整合创造了一个认知合作系统，其中有效的资源分配算法对于提取认知和合作的利益至关重要。其次，我们将研究将动态频谱接入集成到飞蜂窝系统中。Femtocell系统提供高吞吐量、高移动性的服务，以满足新的无线应用更具挑战性的要求。每个飞蜂窝包含一个低功耗、低成本、高吞吐量的基站，通过可靠的高速连接连接到广泛的蜂窝网络。如果没有有效的资源分配、频谱接入和干扰控制方案，Femtocell的效益就会大大降低。

In recent years, wireless applications have become increasingly crucial while the number of wireless users has constantly been growing. However, the radio spectrum is a scarce natural resource; and its majority is allocated to well-identified licensed users. In general, licensed users are unwilling to share their spectrum with other unknown users and a large part of the licensed spectrum is not fully utilised. Cognitive Radio (CR) technology (based on software defined radio) presents a practical approach to spectrum scarcity and to its underutilisation. This is achieved by implementing the concept of dynamic spectrum access such that unlicensed CR users can dynamically access the licensed spectrum, without causing harmful interference to licensed users. This research program focuses on developing original and innovative efficient resource allocation schemes for the integration of CR technology in emerging wireless networking techniques. First, we will investigate CR nodes operating with cooperative communication - that builds a virtual multi-antenna system by making use of the antennas available in the neighbour nodes. This integration creates a cognitive cooperative system where efficient resource allocation algorithms are critical for extracting the benefits of both the cognition and the cooperation. Second, we will study the integration of dynamic spectrum access into femtocell cellular systems. Femtocell systems provide a high-throughput high-mobility service to answer the more-challenging requirements of new wireless applications. Each femtocell contains one low-power low-cost high-throughput base station connected to the wide cellular network through a reliable high speed connection. Femtocell benefits can be significantly curtailed without efficient resource allocation, spectrum access and interference control schemes.