Research On Routing Mechanism In Cognitive Network Based On Link-State Prediction

The demand for spectrum grows rapidly, because of the increasing mobile terminals and widely deployed high-speed wireless network services. So, the cognitive network becomes a hot point for research. Compared to the existing fixed spectrum allocation policy of the traditional network, cognitive network allows unauthorized users to access authorized spectrum space, and to a certain extent, solves the problem of spectrum waste. Benefit by the spectrum switching function, the links in cognitive network dynamically changes in time domain, space domain and spectrum domain. The dynamic changing feature makes the traditional routing scheme unsuitable for the cognitive network.To solve the key problem of cognitive network routing, this paper proposes a cognitive routing scheme based on link state prediction. The scheme deploys link state prediction for improving routing stability, controls routing queues for decreasing queuing delay and uses load balance for increasing end-to-end throughput. The Link-state prediction algorithm makes use of the relative position of the unauthorized users and authorized user, the moving direction of the unauthorized users to predict the interference of unauthorized users to authorized users. The aim of the link-state prediction module is to decrease the interference for authorized users, and at the same time improve unauthorized users routing performance. Routing decision algorithm, considering the load balancing, is to reduce packet waiting delay on a link. Routing mechanism based on link-state prediction decreases the interference of the unauthorized users for the authorized users, which at the same time enhances the routing performance for the unauthorized users. Then we conducted a series of simulation experiment based on our routing protocol in NS2platform. It proves that our routing scheme helps to reduce the end-to-end delay.