Research On The Spectrum Resource Management Based On Cognitive Wireless Networks

From the perspective of international and domestic progress, the research of cognitive wireless network will provide a good foundation for future wireless networks. In particular, the dynamic use of spectrum holes can effectively solve the problem of inadequate frequency resources. With the rapid development of cognitive radio technology and the hardware processing capacity, the shortage of spectrum resources in the existing fixed spectrum allocation mechanism could be solved by cognitive wireless network.This paper focuses on the topic of spectrum management in cognitive radio. As a kind of special, precious and non-renewable source, wireless spectrum is an important approach for transmitting information. With the increase of business needs, the demand for spectrum resources is also growing accordingly. The main purpose of this paper is exploring how to meet people’s business needs by making full use of limited spectrum resources. Due to the high variability of practical network environment and spectrum resources, efficient reliable and fair approaches of spectrum management become an important issue. With the purpose of constructing a comprehensive dynamic spectrum management model, this paper hope to find the optimal spectrum allocation mechanism, based on the premise of guaranteeing the QoS requirement of cognitive user. The model can improve utilization of spectrum resources through some techniques, including:dynamic prediction, distributed collaboration detection, distributed cross-layer design, the algorithm of fairness access, power control.Chapter 1 introduces the background of this paper, and point out that the cognitive wireless network has been recognized the preferred technology to solve the current and future spectrum resource conflicts. It is considered the basis for the next-generation wireless networks. It has a relatively broad prospect, but there are some urgently technical problems. Then the domestic and international research status about the cognitive wireless network is introduced. Finally the author summarizes the purpose and significance of this paper.Chapter 2 describes the key technologies of the spectrum resource management technology in cognitive wireless network. The author firstly describes the relevant characteristics of the spectrum resources. Because the characteristics of spectrum will affect the use of the spectrum resource, the understanding of the spectrum resources is very important. Then the author introduces the evaluation criteria of the spectrum resource. Finally the author introduces the key technologies associated with the spectrum management, including:spectrum allocation model, power control, sensing technology, spectrum etiquette and the spectrum switch. Through these presentations we can understand various characteristics of spectrum management in cognitive wireless networks, and various difficulties.Chapter 3 presents and analyzes a new spectrum resource management program. The core idea of the program is that the user who has the higher values of QoS priority will has the right to use the spectrum resources. Firstly the central base station will generate two queues, named the cognitive user queue and the available spectrum band queue. The position of the cognitive user related to the values of QoS priority in the cognitive user queue. Then the central base station matches the two queues to complete the allocation of spectrum resources. At the end of this chapter, the problem of the access conflict are described, the author uses the two handshake mechanism to avoid the conflict of the transmission control channel.Chapter 4 introduces the specific spectrum allocation plan base on the introduced spectrum resource management program. Firstly the author proposes a new spectrum allocation model based on graph theory. The model considers two requirements: maximizing the total profit and minimizing the present probability of authorized users. Simulation results indicate that the new model can be better to reduce the present probability of authorized users at the expense of some throughput performance. However, the loss of throughput performance will not be much. In practice the new algorithm can provide higher QoS guarantee for cognitive user and can reduce the probability of re-spectrum allocation. Because the new model did not consider the channel capacity constraints of the relay use in multi-hop network; the second part of this chapter introduces a new spectrum allocation model based on linear programming. The author proposes a new spectrum allocation model and provides the practical solution of the problem. The objective of this model is to maximize the average throughput of the entire network. Simulation results verify the validity of this model.Chapter 5 introduces the power control model. Firstly the author proposes a new power control model based on game theory. The model considers the SINR satisfaction, and use the penalty function to limit the interference between different users. At the same time the author verify the existence and uniqueness of Nash equilibrium. Simulation results verify the validity and the fast convergence of this model. Because the power control model did not consider the multi-hop network condition; the second part of this chapter introduces a new power control model based on linear programming. The objective of this model is to minimize the total transmit power. And the author provides the details solving process. Simulation results verify the validity of this model.At last, the author summarizes the work of this paper, and proposes the future research directions.