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With portable computers and handheld computers have become more popular, the rapid development of wireless communication technology, driven by the development of the network protocols. Advances in communication technology makes wireless transmission network (such as cellular networks and satellite networks) are very popular, WLAN, GSM, PCS, CDMA and UMTS equipment and services: applications of \\The new network and new applications demand caused by the timely application of wireless networks - Ad hoc network design and research. Adhoc network does not rely on fixed infrastructure, self-organizing wireless network, the network is convenient, fast, without time and space restriction applies both to the rescue, meeting, battlefield, adventure, remote or hazardous environments the target monitoring occasions, can also be used for the expansion of the cellular terminal network. Ad Hoc networks with wireless transmission, highly dynamic topology, no center, multi-hop routing features, which makes many of the problems become complex and difficult to achieve. The various protocols and technologies used in fixed wired networks and cellular networks can not be directly applied to the Ad Hoc network. Therefore, since the proposed date, Ad Hoc networks attracted enormous attention and widespread interest in all aspects, until now, there are still many problems to be solved, the Ad Hoc network. Ad hoc network access layer and network layer protocol, both in this context the study, improvement and comparative studies, focusing on the individual network layer protocol feasibility program. Chapter overview of the definition, characteristics and development of Ad hoc networks. Focused on the description of the Ad hoc network architecture, and key technology. The second chapter of the main classification Ad hoc network access protocol and network layer protocol of the MAC layer. Analysis of several typical channel access protocol and introduce four types of routing protocols. The third chapter is the focus of this paper, first introduced the main content of the on-demand routing protocol DSR protocol put forward new ideas, and then, based on this agreement, proposed a new algorithm to find and store the alternative route, focus on improving alternative route timeliness , making it when the trunk path disconnection, real aging alternative of the connection can be formed, thereby improving the data packet transmission efficiency of the entire network, and reduce interrupt routing continued access time. Modeling simulation and analysis of simulation results on the environment concluded. Chapter IV summarizes the development and application prospects of the Ad hoc network.
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