In a traditional cellular system, the call requests initiated by mobile stations （MSs） must be carded through a base station （BS） via the cellular interface, but when MSs are located in the dead spots, their call ...In a traditional cellular system, the call requests initiated by mobile stations （MSs） must be carded through a base station （BS） via the cellular interface, but when MSs are located in the dead spots, their call requests will be blocked because the MSs cannot communicate with the BS. It is considered to relay these blocked calls requested using Ad-hoc network, which will improve the performance of the system as a whole. This article first introduces a novel architecture of the two-hop-relay cellular system in the dead spots, and then analyzes and compares the call blocking rate of the traditional cellular and the two-hop-relay cellular system respectively under three different conditions. The first and second conditions are the traditional cellular system without and with taking account of the effect of the dead spots. The third condition is the two-hop-relay cellular system with taking account of the effect of the dead spots. Numerical analytical result shows that the two-hop-relay cellular system can obtain lower call blocking rate than the traditional cellular system when considering the effect of dead spots. Consequently, this novel architecture can resolve the problem of coverage limitation of a traditional cellular system effectively.展开更多
Cognitive radio （CR） is found to be an emerging key for efficient spectrum utilization. In this paper, spectrum sharing among service providers with the help of cognitive radio has been investigated. The technique o...Cognitive radio （CR） is found to be an emerging key for efficient spectrum utilization. In this paper, spectrum sharing among service providers with the help of cognitive radio has been investigated. The technique of spectrum sharing among service providers to share the licensed spectrum of licensed service providers in a dynamic manner is considered. The performance of the wireless network with opportunistic spectrum sharing techniques is analyzed. Thus, the spectral utilization and efficiency of sensing is increased, the interference is minimized, and the call blockage is reduced.展开更多
Because of no strict expression of calculating call blocking probability （CBP） in the solution procedure of virtual-path bandwidth allocation problem, the process of calculating bandwidth through CBP and traffic loa...Because of no strict expression of calculating call blocking probability （CBP） in the solution procedure of virtual-path bandwidth allocation problem, the process of calculating bandwidth through CBP and traffic load adopts the iteration algorithm in common, which is an inverse process of calculating CBP through traffic load and bandwidth. It limits computing speed by a long way because of including recursion. An approximate algorithm of bandwidth is presented. We compare the performance of this algorithm with that of another classical algorithm and conclude that the former makes a great increase in speed with little error about 2 %.展开更多
基金the Hi-Tech Research and Development Program of China（2006AAQIZ208）；the Natural Science Foundation of Jiangsu Province（BK2QQ7236）；the Six Trades Talent Highland Foundation of Jiangsu Province.
文摘In a traditional cellular system, the call requests initiated by mobile stations （MSs） must be carded through a base station （BS） via the cellular interface, but when MSs are located in the dead spots, their call requests will be blocked because the MSs cannot communicate with the BS. It is considered to relay these blocked calls requested using Ad-hoc network, which will improve the performance of the system as a whole. This article first introduces a novel architecture of the two-hop-relay cellular system in the dead spots, and then analyzes and compares the call blocking rate of the traditional cellular and the two-hop-relay cellular system respectively under three different conditions. The first and second conditions are the traditional cellular system without and with taking account of the effect of the dead spots. The third condition is the two-hop-relay cellular system with taking account of the effect of the dead spots. Numerical analytical result shows that the two-hop-relay cellular system can obtain lower call blocking rate than the traditional cellular system when considering the effect of dead spots. Consequently, this novel architecture can resolve the problem of coverage limitation of a traditional cellular system effectively.
文摘Cognitive radio （CR） is found to be an emerging key for efficient spectrum utilization. In this paper, spectrum sharing among service providers with the help of cognitive radio has been investigated. The technique of spectrum sharing among service providers to share the licensed spectrum of licensed service providers in a dynamic manner is considered. The performance of the wireless network with opportunistic spectrum sharing techniques is analyzed. Thus, the spectral utilization and efficiency of sensing is increased, the interference is minimized, and the call blockage is reduced.
基金This project was supported by National Natural Science Foundation of China (69972015) Guangdong Provincial NationalScience Foundation (31391) .
文摘Because of no strict expression of calculating call blocking probability （CBP） in the solution procedure of virtual-path bandwidth allocation problem, the process of calculating bandwidth through CBP and traffic load adopts the iteration algorithm in common, which is an inverse process of calculating CBP through traffic load and bandwidth. It limits computing speed by a long way because of including recursion. An approximate algorithm of bandwidth is presented. We compare the performance of this algorithm with that of another classical algorithm and conclude that the former makes a great increase in speed with little error about 2 %.
