Research On Handoff Decision Algorithm Based On Multi-attribute In Integrated Satellite And Terrestrial Networks

With satellite communications technology developing towards broadband andall-IP based, it is trying to design integrated with terrestrial cellular networks tocombine their most favorable part. Due to the difference of access technologies,system architecture, communication capabilities and traffic support in variouswireless communication network, the conventional mobile terminal withoutmulti-access technology is not able to meet the seamless user mobility, trafficcontinuity and dynamic adaptation of the network. As the basis of the features, userterminals should have the capability of intelligent network selection and seamlesshandoff. Therefore, the effective handoff mechanism with multi-attributedecision-making(MADM) ability is an important research in integrated satellite andterrestrial network(ISTN).Traditional MADM algorithm is to set a weighting function for an optimalhandoff target with entering the decision-making factors related to the objectiveconditions, and then the optimal handoff target network will be obtained through thegiven MADM model. For users of same weighting function and candidate network,the traditional algorithm will give almost the same target network, resulting innetwork congestion and an increased failure probability of handoff and new callrequest. In addition, it will always select the network with large service radius ashandoff target when users have a high-speed mobility. With the service requestfrequently and groups in high-speed, the network will be congestion soon.In order to solve the problems above, this thesis firstly did a research onvertical handoff procedure in ISTN. Then it proposed a novel handoff decisionmethod towards user experience and design its module through selecting thenetwork with the lowest user experience difference for handoff. Due to handoffrequest of the mobile terminal in high speed, it adopted the fuzzy method to designa module. This thesis also proposed a handoff decision method combining the speedperception with user experience and analytic-hierarchy-process method respectively.Finally, simulation performance verified the correctness of the proposed handoffdecision algorithm and proved the superiority in reducing the probability of handofffailure and new call blocking. Moreover, the system can maintain a higher averagenetwork load, which indicates the superiority of resource allocation among thewhole network.