Research On The Power Control And The Improvement Of TCP Protocol For Ad Hoc Networks

Mobile Ad hoc Networks (MANET) which is a new kind of wireless mobile network, has the advantages of easy constructing, fast self-organization, strong adaptability, low cost etc, and it has broad application prospects in military and commercial fields. Ad hoc networks which is formed with a group of independent mobile nodes connecting with each other, is independent of the fixed infrastructure and is managed with the distributed methods, meanwhile it is a self-creation, self-organization and self-management. Ad hoc networks isbecoming a hot spot in the related research area.Freedom and flexibility are two major characteristics of Ad hoc networks, and it leads the changes of node density quickly, the huge consumption of energy, etc. The algorithm of Step Power Control of Ad hoc Node is given to meet these characteristics, which can control the radiation power according to different states of network when the state are being in the state of waiting and communication working state. The algorithm provides the different power radiation due to the time slice and current topological information of the waiting state. When the node transfers into the communication state, an appropriate step is chosen from the step powers according to the routing information and topology. Being the communication state, the current time slice of the power radiation, following radiation power and time slice is determined by the communication connectivity and fault rate of current power radiation.Finally, the current TCP protocol and the communication features of Ad hoc network are analyzed in detail, and a new ACCOUNT TCP protocol is proposed. The protocol gives an improvement on the testing with little and starting quick to make the communication links to be used quickly when the network environment is effective. To deal with the feature of high overhead of the lower network link, this thesis figures out methods of waiting of intensive node, sorting ability, elongate retransmission waiting time, error correction fields adding, selection retransmission, double sliding windows and packet-loss difference and processing respectively. It improves the utilization ratio of information packets of destination nodes and decreases the dependences of lower level. The performance of TCP in Ad hoc networks and transport layer are improved.