Improvement Of Mobile-Centric Transport Protocol For Wireless Local Area Networks

With the increasing application of wireless LANs, how to connect the wireless networks to Internet with a wide bandwidth becomes more and more important not only in science but also in economics. A high performance wireless Internet transport protocol is the key to solve this problem.In order to solve the promblems of traditional TCP in wireless networks, we propose the Mobile-Host-Centric Transport Protocol (MCP). MCP adopts the sender-centric control mechanism when the mobile host is the sender, however, when the mobile host is the receiver, MCP changes to the receiver-centric control mechanism. Previous work in our lab has already demonstrated the feasibility of MCP. Without adding any special improvement strategy, MCP has similar performance to TCP. In this thesis, based on our previous work, we firstly complete and strengthen the basic principles of MCP, and implement the fundamental function modules of MCP in Reno version under the simulation software NS2.Secondly, when MCP uses receiver-centric control, comparing with the traditional sender-centric control of TCP, it has certain advantages on improving the performance of the transmission control protocol. By utilizing those advantages, we propose two end-to-end methods, selective request (SREQ) and skipping request (skipping REQ).Thirdly, to further enhance the performance of MCP in WLANs and effectively make use of available information at the wireless nodes, we introduce a cross-layer design. The MAC layer of the wireless nodes collects useful information and transmits it to the transport layer, where MCP utilizes this feedback information to optimize the current congestion control algorithm.Finally, we have done a number of different simulations to evaluate the performance of MCP with skipping request mechanism and MCP together with selective request and cross-layer mechanisms. Simulation results demonstrate that MCP, with the improvement methods we have proposed in this thesis, outperforms the traditional TCP by improving the end-to-end throughput significantly with little affection towards the fairness.