Research On Capacity Of Congitive Radio Network

The rapid development of mobile data service improves users’ quality of experience (QoE), and valuable spectrum resource seems more scarce. Driven by the innovation of varieties of mobile communication technologies, wireless network system as formed the network pattern of coexistence of many radio access technologies, which makes the network connectivity more serious. Cognitive radio network, which was proposed by Joseph Mitola in1999, is designed to improve the spectrum efficiency and promote the convergence of heterogenous networks and further users’ QoE. Study on cognitive radio network draws more and more attention.Network capacity is an important metric of network performance, which aims to evaluate network performance and provide theory evidence for high quality network building and the reasonable allocation of network resources. Wireless communication networks will become heterogenous multi-service network, so it is very essential to investigate the network capacity. The dissertation focuses on network capacity evaluation for cognitive radio network with different spectrum access schemes. Firstly, cognition flow-core concept of cognitive radio network is analyzed and key technologies are presented; Secondly, three spectrum sharing schemes are presented as below.1. The hybrid overlay/underlay spectrum sharing scheme, where underlay and overlay access approaches are combined to improve the transmission capacity of the SR network. Analysis and numeric results show that hybrid mode has greater superiority than either overlay mode or underlay mode on the transmission capacity of the SR network, especially when the primary network has light load.2. The spectrum sharing scheme with preservation regions to avoid excessive interference, and transmission capacity of cognitive radio networks with this spectrum sharing scheme is presented. From analysis and numeric results, this scheme shows its advantage.3. The spectrum sharing scheme with primary outage constraint, where secondary users access spectrum under the primary outage constrict. Compared with the related works in the literature which mainly give order sense results like scaling laws, we derive an expression of the single-hop transport capacity for the secondary network under the outage constraint of the primary network. The Aloha medium access control (MAC) protocol and the nearest neighbor routing protocol are considered.We study and verify the proposed spectrum sharing schemes from the perspective of theoretical analysis and numerical analysis.Our dissertation conducts the research with the support from national973project "Behavior analysis and network performance research on cognitive radio network" and related works have been published in IEEE international conferences.