Research On Channel Assignment Method In Heterogeneous And Hierarchical Cognitive Radio Sensor Networks

With the development of wireless communication and sensor technology, wireless sensor networks(WSN) is widely favored by people for its increasingly important role in smart home, disaster monitoring and other aspects. However the lack of communication bands seriously restrict the development of WSN. Cognitive radio sensor networks(CRSN) with dynamic spectrum management ability can improve the utilization efficiency of spectrum resources and the performance of network communication, which has gradually get people’s attention and recognition. Meanwhile, with the demand increase and the scale expend of network, heterogeneous and hierarchical CRSN which have strong endurance and spectrum resource management capabilities are more prominent. As a key factor in influencing the performance of CRSN, it is important to improve and consummate the method of channel assignment and energy consumption optimization.CRSN is a wireless communication system, which is introduced cognitive radio technology in the traditional WSN. According to the differences between CRSN and WSN, this paper introduces the node structure, the cross-layer spectrum management mechanism and the network protocol architecture of CRSN firstly.Secondly, the common network topology models of CRSN as well as their characteristics are presented. The cluster deployment problem of heterogeneous and hierarchical CRSN is solved by means of the improved K-means clustering algorithm. On the premise of avoiding the isolated nodes of network, the clustering number is controlled effectively. The deployment costs and communication energy consumption of heterogeneous and hierarchical CRSN have decreased. This section laid the foundation for the research of the channel assignment and energy consumption optimization.Finally, the channel assignment and energy consumption optimization based on the sustained-transmission rule in heterogeneous and hierarchical CRSN are researched. In the channel assignment process, the centralized channel assignment task is completed according to different transmission conditions of network nodes as well as the characteristics of the idle channels and the residual energy of network nodes, which improve the success rate of packet transmission. What’s more, the energy consumption per bit in information transmission process of nodes is reduced through optimizing the packet size adaptation mechanism. Thus, the efficiency of energy utilization of heterogeneous and hierarchical CRSN is improved and the life-time of the CRSN is prolonged.