Research On Access Selection Algorithm In Heterogeneous Wireless Networks

Integration of heterogeneous wireless network is the inevitable result of evolution of next generation wireless network system. The joint radio resource management is an important part of the integration, and the access selection as one of the key technology in radio resource management is becoming a hot issue. In the environment of heterogeneous wireless network, wireless networks differ from each other in many aspects, such as coverage, support of services, cost and so on. It has great significance to propose an access selection algorithm which would provide the best service of wireless network to users and improve the performance of the heterogeneous wireless network system.In the first place, based on plenty of researches in existing access selection algorithms, an access selection algorithm based on VIKOR and triangular fuzzy number is proposed. Uncertain values such as residence time and user preferences can perfectly be expressed by triangular fuzzy number, and it also can express the variation of certain values. VIKOR which is a sorting method based on ideal solution is used to sort the candidate networks. Simulation results show that the proposed algorithm can effectively reduce the gap between the blocking rate of each candidate network, balance the load of each network, and improve the performance of heterogeneous wireless networks.Besides, in order to solve the problem that existing network selection algorithms of heterogeneous wireless network do not consider the diversification of network’s status after the access, a selection algorithm based on Markov model is proposed. The algorithm takes into account that the diversification of available bandwidth will affect the QoS of consumer’s communication services. First, Markov model is used to predict the diversification of network’s status after the access via transition probability. Then weights of evaluating indicators should be determined by entrogy weight method. At last, by comparing the values of each network, the optical network to access should be selected. Simulation results show that, the algorithm proposed can receive a higher level of load balancing and effectively improve the average blocking rate and packet loss rate.