Smart Phone Based Ad Hoc Network And Its Application

Compared with traditional wireless communications,which are based on cellular base stations or WIFI access points,Ad hoc network proves its advantages characterized with independence from communication infrastructure,auto service finding,high dynamic topology,and multi-hop communications.Due to the fact that we are living in an era in which smart phones are widely used,it is of great importance to design and develop smart phone based ad hoc networks and the apps based on them.In this thesis,wireless ad hoc technology and its application in smart phones are investigated.The main work includes the following.1.The route protocols for ad hoc network are analyzed.The typical route protocols include active ones,e.g.,DSDV and OLSR,and passive ones e.g.,AODV and DSR.To decide what protocols are more suitable for smart phone based applications.their performances are simulated and compared on NS2 tool.The results show that OLSR proves the best performance in average delay and transmission rate,which can be explained by the fact that OLSR employs multipoint relay mechanism for more reliable transmission and selective control technology for avoiding flooding phenomena,thus ensuring the more efficient route selection and its timely update.2.Ad hoc networking for smart phones: Considering the fact that Android operation system dominates the smart phone operating system market and this trend will last for a long period,we choose Android based phones in our design.By borrowing the developing experience from open source project SPAN,IP address and DNS server configuration,and correction of wireless SSID and air interface control,etc.are implemented for ad hoc networking.In addition,OLSR protocol configuration is done by revising the Olsrd codes.And by downloading the codes developed in the PC to phones,the wireless ad hoc network is realized for smart phones.3.Application development: based on the ad hoc network developed above,a phone-based poll system is designed and implemented,including the software development for clients and server.In the designed system,smart phones communicate with each other and the server in a manner of ad hoc network,which is independent from the basic infrastructure.To the security of the communication,DES encryption,an algorithm widely used in the wireless communications,is analyzed and transplanted into the designed system.In summary,the route protocols are simulated and analyzed for ad hoc network design,a smart phone based ad hoc network is realized and a phone based poll system is designed and developed as an application example.