Research Of Optimization Algorithm For Intelligent Gateway In Heterogeneous Networks Based On Cross-layer Method

Along with the rapid development of wireless network and the encasement of themobile terminal, Internet will form a heterogeneous networks which consisting ofwired networks, wireless networks and satellite networks. Mechanism of congestioncontrol improvement is also more difficult due to the complexity of network structure,and the bottleneck of data transmission is more and more obvious. How to make theinformation transmission function of heterogeneous networks can transform as high-speed, high-quality, high-reliability as wired networks have become an active area ofresearch. In view of the characteristics of heterogeneous network, this paper proposeda kind of intelligent gateway optimization algorithm using the method of cross-layerdesign.First of all, this thesis introduces the theoretical basis of an intelligent gatewayand the concept of cross-layer method. For the characteristics of wireless link inheterogeneous networks of the larger impact on the network transmission performance,five different types of intelligent gateway were been designed based on the idea ofsplit-connect method, and compared all kinds of intelligent gateway to prove itadvantages or not. After experiment and improve continuously, an algorithm has beenwritten for the intelligent gateway to adapt to heterogeneous network, named SCTP.Secondly, in order to improve throughput performance of the gateway inheterogeneous networks, following three improvements have been done. First: thegateway used an improved program of split-connect, originally a TCP data connectionis divided into two virtual data streams, according to the features of a wireless link in aheterogeneous network, protocol was modified. Second: cross-layer design abandonedthe single-traditional factor to determine the network status, extract the requiredparameters from the OSI layers and then analyzed. These results provide reliable databasis for intelligent gateway. Third: through accurate cognition on networkperformance which used the cross-layer parameters, we designed algorithm PLC and new parameters adjustment algorithm: algorithm PLC analysis of cross-layerparameters to determine the probability of different kinds of packet loss, and improvethe algorithm of packet loss event by adjusting the data transfer; new parametersadjustment algorithm Using fuzzy mathematics and cross-layer design method, andthen design the new parameters of MDP and ToC, to optimizing the gateway algorithm.Finally, we simulated SCTP in NS2; the result shows that SCTP can makeimprovement for heterogeneous network. In this paper, heterogeneous networktransmission control conducted in-depth research. In the hope that such research canbe optimized algorithm has made a contribution to the intelligent gateway.