频谱异构环境下基于协作感知的认知无线ad hoc网络MAC技术研究

In a practical wireless communication system, different spatial locations of communication nodes may result in the difference of their available spectrum resources. To overcome the difficulty of spectrum resource management caused by this environment of spectrum heterogenity, cognitive radio ad hoc networks should adopt the technique of cooperative sensing to enhance the accuracy and spatial range of spectrum sensing by network nodes, control the access of heterogeneous spectrum resources by network nodes reasonably based on the sensing results, and provide as much as possible the communication spectrums that are available for both transmitters and receivers. Thus the present project proposes to perform throrough research on the design of MAC protocols for cognitive radio ad hoc networks based on cooperative sensing in the environment of spectrum heterogenity. By exploring the methods of distributive cooperative sensing with low time synchronization requirements and relatively fixed additional costs, we shall breakthrough the design of MAC protocols for cognitive radio ad hoc networks based on various mechanisms for exchanging control information, i.e. out-band common control channel, in-band frequency hopping and in-band clustering,. Hopefully, this research would disclose the general principle for cognitive radio ad hoc networks to perform self-adaptive spectrum management in the heterogeneous environment of available spectrum resources. Through the software- or hardware-based simulation, verification and performance evaluation on the proposed key techniques and methods, this project could build a solid basis for solving the key problems of spectrum resource management in implementing practical cognitive radio ad hoc networks.

在实际的无线通信系统中，由于通信节点所处空间位置不同，其可用的频谱资源也并不相同。为克服这一频谱异构环境所造成的频谱资源管控困难，认知ad hoc网络需要利用协作感知技术增强网络节点频谱感知的准确性和空间范围，并根据感知结果合理控制网络节点对异构频谱资源的接入，以尽可能地提供收发皆可用的通信频段。为此，本项目拟在频谱异构环境下针对基于协作感知的认知ad hoc网络MAC协议设计进行深入研究，在探索低时钟同步要求和附加开销相对固定的分布式协作感知方法的基础上，突破基于带外公共控制信道、带内跳频和带内分簇等多种控制信息交互方式的认知ad hoc网络MAC协议设计，揭示认知ad hoc网络在可用频谱资源不均衡环境中实现自主适变频谱管控的一般性规律，并对所提出的关键技术和方法进行基于软/硬件的仿真验证和性能评估，为解决认知ad hoc网络在实用化过程中所面临的关键性频谱资源管控问题奠定基础。

为克服频谱异构所造成的认知ad hoc网络频谱资源管控困难，本项目深入研究了基于协作感知的认知MAC协议设计问题，在探索分布式协作感知方法的基础上，突破了基于带外公共控制信道、带内跳频和带内分簇等多种控制信息交互方式的认知ad hoc网络接入控制机制。.首先，本项目所提出的基于能量检测的分布式协作感知机制能在缩短感知融合时间，降低时钟同步要求，以及具备相对固定附加开销的同时，获得比传统OR、AND和K-out-of-N等感知融合判决机制更低的感知融合虚警概率、比OR和AND法则更低的融合错误概率、以及与K-out-of-N法则类似的融合错误概率。其次，在基于带外公共控制信道的认知MAC协议研究中，本项目分别针对不同的应用场景提出了一种业务自适应无线频谱资源租赁技术、一种适用于D2D通信的能效优先控制信道检测技术和一种适用于全双工通信的频谱和功率资源联合分配技术，并基于上述技术所获得的通信频谱资源设计了一种基于带外公共控制信道的认知ad hoc网络MAC协议，以更好地适应认知节点动态变化的通信业务需求和提升无线频谱资源的利用率。再次，本项目所提出的基于带内跳频的认知MAC协议不依赖于任何固定和预设的公共控制信道，能有效限制授权用户通信对认知ad hoc网络的干扰范围，降低控制信息交互所需的通信附加开销，避免基于单个公共控制信道的认知MAC协议所面临的控制信道流量饱和问题，因而具备更强的环境适变和抗干扰能力。最后，本项目所提出的基于带内分簇的认知MAC协议既具备较低的计算复杂度和节点间的通信开销，又能在确保每个节点簇均具备一定数量控制信道的基础上尽可能地降低全网节点簇的个数，从而在簇内控制信息交互的健壮性和簇间控制信息交互的效率之间取得了优化折中。.综上所述，本项目研究揭示了认知ad hoc网络在可用频谱资源不均衡环境中利用不同方式实现自主适变频谱管控的一般性规律，为解决认知ad hoc网络在实用化过程中所面临的关键性频谱资源管控问题奠定了理论基础。