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

通过向未授权（也称为辅助或认知）用户提供与授权（也称为主要）用户以机会性方式共享无线信道的能力，只要将引入主要用户的干扰保持在预定义的阈值以下，认知无线电技术已成为提高无线频谱资源利用率的有希望的解决方案。认知无线网络的设想是通过异构无线架构和动态频谱接入技术为移动用户提供高带宽，同时提高信道环境的连通性和自适应性。然而，由于二级认知无线电终端的发射限制，该技术在覆盖范围和网络连接方面受到限制。另一方面，协作通信技术在传统无线网络中得到了广泛的研究，并被证明是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力方法。它允许多个无线节点共享它们的资源（带宽和电力），并在信息传递中相互帮助，目的是实现更好的整体性能，即更高的可靠性和效率。此外，编码合作将信道编码与合作通信相结合，在保持与非合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提升。本研究计划的目的是为节能中继认知无线网路中资源分配（中继选择、功率、速率和频道）的基本问题提供一个新的实用框架。将编码协作通信技术集成到认知无线电系统通信协议的设计中，以提高频谱感知和二次传输的性能，在保证服务质量的前提下降低每个认知用户所需的传输功率。预期的结果将为高效开发和运行具有高数据速率的可靠认知无线电网络提供一些科学见解，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。这些成果将对研究团体、无线行业、政府实验室、该领域的从业者和频谱监管机构具有重要意义。

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.