The Design And Implementation Of End-to-end Transmission Protocol In Adhoc

A wireless ad- hoc network is a kind of self-organizing network dynamically built by wireless networking devices build. It does not require the fixed network infrastructureand all nodes in it have equal positions, which is able to rapidly construct a network platform by a special network protocols and algorithms for military and civilian applications. Because of its high flexibility, Ad Hoc Networks have have gained widespread concern and became the focus of research.In Wireless ad-hoc network, Radio channel high error rate, time-varying, vulnerable to interference and other characteristics, packet’s multi- hop transmission and node’s fast- moving makes packet loss rate is high. for the transmission of important information, you need a reliable transport protocol to solve the packet loss issue. TCP is based on the traditional wired network connection-oriented, reliable transport protocol. Its congestion control mechanism assumes that packet loss is caused by network congestion. If the traditional TCP congestion control mechanisms is directly used in wireless ad- hoc network, non-congestion packet loss results in frequently unnecessary congestion control. And the lower transmission window causes a sharp decline in the transmission. So the transmission performance is not guaranteed. In addition, multi- hop transmission in wireless ad- hoc network also led to transmission fairness issues of end-to-end between "long- flow" and "short- flow". In summary, exploring end-to-end transport protocol adapted to wireless ad-hoc network becomes very important.On analyzing the basic principles of traditional TCP and congestion control algorithms, End-to-End transport protocol VTCP have been proposed to adapt to wireless ad-hoc network in this paper. It includes imporving congestion control algorithm and resolving multi- hop transimission fairness. Through advantages and defects of analyzing the existing congestion control algorithms, This paper propose a congestion control algorithm-TCP Effective VAW adapting the wireless ad-hoc network and improving transmission performance. O n analyzing the reasons for fairness of end-to-end transmission, multi- level cache priority queue scheduling mechanism is designed to improve the unfairness between "long flow" and "slow flow". Finally, on the hardware platform of ARM and FPGA, the ad-hoc network system and end-to-end transport protocol VTCP have been implemented. And the performance and fairness were tested in several scenes to verify the validity of this protocol.