MAC And TCP Cross-layer Cooperation-based Performance Optimization In Wireless Ad Hoc Network

With the rapid development of moden wireless communication and Internet, people has become more and more dependent on mobile information services. This trend is driving the technology of wireless network, which requires low cost and little dependency on infrastructure, to become one of the hottest focuses in academic and professional research. A wireless ad hoc network is a collection of peer wireless mobile or stationary nodes that autonomously form a network without relying on pre-existing fixed network infrastructure and with distributed administration. This kind of network will play an increasingly important role in many environments, e.g. military communication, disaster recovery, search-and-rescue and distributed computing. Performance optimization is one of the most important objectives in the design of wireless network protocols, cross-layer cooperation is main strategy to enhance performance in Ad Hoc network. In this thesis,a method based on MAC protocol and TCP cross-layer cooperation to improve the performance of Ad Hoc network are presented, the main contributions maked in this thesis as described in the following paragraphs.The thesis gives a review of problems in the IEEE 802.11 MAC Ad Hoc network. With an extensive analysis of IEEE 802.11 MAC, and the hidden terminal problem in single hop WLAN, the extended hidden terminal problem still exist after used RTS/CTS in Ad Hoc, the greatest source of extended hidden terminal problem in Ad Hoc is network overload. With an extensive analysis cross-layer interaction in 802.11 networks, the extended hidden terminal problem is the main source of low throughput and its instability in Ad Hoc.Based on the cost and renewal processes and markov processes, the performance of IEEE 802.11 MAC Ad Hoc network is analysed.The following three kinds of sences are involoved, tcp sender window is 2 and delayed acknowledgement parameter is 1, tcp sender window is 2 and delayed acknowledgement parameter is 2, tcp sender window is 3 and delayed acknowledgement parameter is 3.The thesis gives a review of problems of TCP in Ad Hoc network,and the proposals to improve the performance of Ad Hoc network. A new method based on cross-layer...