Resource Allocation in Coded Cooperative Relay for Multi-channel Cognitive Radio Networks

通过以机会主义的方式向未授权(也称为次要或认知)用户提供与授权(也称为主要)用户共享无线信道的能力，只要引入到主要用户的干扰保持在预定义的阈值以下，认知无线电技术就成为提高无线频谱资源利用率的一种有前途的解决方案。认知无线电网络通过不同的无线体系结构和动态频谱接入技术为移动用户提供高带宽，同时改善信道环境的连通性和自适应性。然而，由于对次级认知无线电终端施加的发射限制，该技术在覆盖和网络连接方面受到限制。 另一方面，协作通信技术已经在传统无线网络中得到了广泛的研究，并被证明是一种通过利用分散节点上的空间分集来对抗无线信道的不利影响和提高系统性能的有效方法。它允许多个无线节点共享它们的资源(带宽和功率)，并在信息传输中相互协助，目标是实现更好的整体性能，即更高的可靠性和效率。此外，将信道编码与协作通信相结合的编码协作在保持与可比较的非协作系统相同的信息速率、发射功率和带宽的同时，为各种信道条件提供了显著的性能增益。 本研究的目的是为能量高效的基于中继的认知无线电网络中的资源分配(中继选择、功率、速率和信道)这一基本问题提供一种新的实用框架。这将把编码协作通信技术融入到认知无线电系统的通信协议设计中，以提高频谱感知和二次传输的性能，并在保证服务质量的情况下降低每个认知用户所需的传输功率。 预期结果将为高数据速率可靠认知无线电网络的有效开发和运营提供一些科学见解，从而通过促进认知无线电技术的大规模部署，对无线通信的未来和发展产生重大影响。这些结果将对研究社区、无线行业、政府实验室、该领域的从业者和频谱管理机构具有重要意义。

By providing unlicensed (also known as secondary or cognitive) users the capability to share the wireless channel with licensed (also known as primary) users in an opportunistic manner, as long as the interference introduced to primary users is kept below a predefined threshold, cognitive radio technology has emerged as a promising solution to improve the utilization of wireless spectrum resources. Cognitive radio networks are envisioned to provide high bandwidth to mobile users via heterogeneous wireless architectures and dynamic spectrum access techniques, while improving connectivity and self-adaptability of channel environment. This technology is, however, limited in coverage and network connectivity due to emissions restrictions imposed on secondary cognitive radio terminals. On the other hand, cooperative communication technology has been studied extensively for traditional wireless networks and shown to be a powerful approach to combat the detrimental effects of wireless channels and improve system performance by exploiting the spatial diversity over dispersed nodes. It allows multiple wireless nodes to share their resources (bandwidth and power) and assist each other in information delivery, with the objective of achieving better overall performance, i.e. greater reliability and efficiency. Moreover, coded cooperation, that integrates channel coding with cooperative communication, provides significant performance gains for a variety of channel conditions while maintaining the same information rate, transmit power and bandwidth as a comparable non-cooperative system. The aim of this research program is to provide a novel practical framework for the fundamental problem of resource allocation (relay selection, power, rate, and channel) in energy-efficient relay-based cognitive radio networks. This will integrate coded cooperative communication technology into the design of the communications protocols of cognitive radio systems to improve the performance of both spectrum sensing and secondary transmissions, and to reduce the required transmission power of each cognitive user with quality-of-service guarantee. The anticipated outcomes will provide some scientific insights on issues related to the efficient development and operation of reliable cognitive radio networks with high data rates, and thus strongly impact the future and evolution of wireless communications, by contributing to the large-scale deployment of the cognitive radio technology. These outcomes will be of significant importance to the research community, the wireless industry, government labs, the practitioners in the field, and spectrum regulatory agencies.