| With the rapid development of mobile devices and mobile wireless network technologies, people can surf the Internet anywhere at anytime, getting rid of the traditional wired Internet constrains. However, the mobile devices connect with each other via base station facilities, even in a small local scope. When the tsunami, earthquake and other natural disasters destroy the base station facilities or in the very remote places, people will not be able to communicate with each other. Mobile Ad-hoc network can solve these problems well.Mobile Ad-hoc network is a kind of self-organized wireless network which does not depend on the base station facilities. Its network topology structure is flexible. It is convenient to build an Ad-hoc network. At present, Ad-hoc network has become the hotspot of the wireless network at home and abroad. Many domestic and foreign research institutions, universities and the army have conducted in-depth research on mobile Ad-hoc network and its applications. Applications of Ad-hoc network are extensive, which can be used in the military, personal communication, wireless sensor network and so on. Recently, some domestic and foreign companies are very interested in the research of Ad-hoc network, and are preparing to apply Ad-hoc network to real life, such as vehicle communication.Currently, mobile devices are diverse, such as mobile phones and ipad. The Android mobile phone is the most popular in the market in recent years, and market share ranks first. Android system is a free open source operating system, which is developed by google. Android source code is open to the public, and it can be developed purposely again by equipment manufactures or researchers based on market conditions. Wi-Fi function module exists in the Android system. If it is in Ad-hoc mode, several Android devices can form an Ad-hoc network.In this thesis, the method of the multi-hop communication implemented by the actual Android mobile phones instead of the simulator is introduced. The standardization of the aodv routing protocol, which is transplanted into the Android system, is realized. Research and experiments are conducted on Motorola defy(ME526) mobile phone platform and Android OS 2.3.3 software platform. The main research works are as follows. Firstly, because the Android system released by manufactures does not support Ad-hoc mode, the underlying Wi-Fi configuration files need to be modified to support the Ad-hoc mode. Secondly, the battery power of mobile phone node is limited, and it is not very convenient to replace the battery frequently. In order to maximize the lifetime of mobile phone node, an on-demand routing protocol named aodv(ad hoc on-demand distance vector routing) is adopted, so that mobile phone node does not need real-time detection and maintenance to the entire network routing. Source codes of the aodv routing protocol, which are rewritten by Java, are analyzed and debugged in the experiments. Data transmission format of source code is redesigned to realize the standardization in accordance with the international standard RFC 3561, which make it possible to connect with any Ad-hoc networks using standard aodv routing protocol. Then the improved source code of aodv routing protocol is compiled into jar package by eclipse software for application call. Finally, using the UDP communication technology, communication transmission applications are developed, and some related experiments on the validation of network establishment, and verification of routing establishment and maintenance have been carried out. The data transmission time and the rate of successfully received data packet are analyzed.To test the data communication performance of the established Ad-hoc networks, a large number of tests are conducted in different site and different distances, and the experimental results are analyzed in detail. Experimental results show that several Android mobile phones can successfully establish an Ad-hoc network, and can undertake multi-hop transmission communication of the text, and build and maintain routing.Finally, the research works are summarized, and some plans about the following research task are made. |
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