Research On The Transport Protocol Based On Adaptive Network Coding With Loosed Packet Predicted In Mobile Ad Hoc Networks

The performance problem is always a key problem which needs to be solved.In order to solve the problem, the researchers propose the solutions such as theARQ strategy in the link layer, split connections, explicit congestion notification,sending rate control based on network status, cross layer congestion control, and soon. These solutions improve the performance of wireless network to some extent,but the throughput of wireless network decreases because of the non congestion lostpackets. These solutions can not improve the network performance effectively.The emergence of network coding offers a new solution for solving theperformance problem in wireless network. The redundancy feature of networkcoding can mask the disturbance of the random lost packets for the traditional TCPcongestion control and improve the performance of wireless network effectively.The researchers propose the TCP/NC protocol based on network coding. Thisprotocol fixes the redundancy factor parameter and gets better performance in staticwireless network. But fixing the redundancy factor can not improve theperformance effectively in dynamic network like MANET.We realize the adaptive network coding scheme with loosed packet predicted andthe revised protocol TCP/NCA which is based on TCP/NC protocol. First, wedesign the algorithm for predicting packet loss rate. Second, we propose theadaptive control algorithm which selects the redundancy factor dynamically basedon the current packet loss rate. Finally, we realize the adaptive network coding layerin TCP/IP protocol stack. We design the interface between the adaptive networkcoding layer and other layers which make the adaptive network layer becoordinated with other layers in the new TCP/IP layers.We simulate the proposed scheme by NS2in a variety of different scenarios.The simulation results show that the adaptive network coding scheme can improvethe traditional protocol and TCP/NC protocol effectively. The overhead of the newprotocol can be controlled within an acceptable range, and the advantage of thescheme is much greater than the disadvantage.