Research On Routing Protocol For Delay Tolerant Mobile Networks

With the rapid development of low-power wireless communication technology andintegrated circuit technology, there emerged a large number of low-cost, portablewireless devices. The wireless devices connect and exchange data with each other inself-organization mechanism. As the sparse density, mobility and energy consumptioninhomogeneity of the wireless nodes, the mobile network is intermittent connected,showing the characteristics of delay tolerant network. Our works in the thesis are basedon delay tolerant mobile network.Data gathering and routing is one of the major functions of delay tolerant mobilenetwork. Due to the intermittent connectivity and more delay tolerance of the network,traditional routing methods are difficult to directly apply in delay tolerant mobilenetwork. New routing protocols should be designed taking into account specificnetwork applications and the characteristics of delay tolerant network. The thesisfocuses on three specific applications of delay tolerant network: Delay Tolerant MobileSensor Network (DTMSN), Mobile Social Network (MSN), and Vehicle Ad HocNetwork (VANET). We in-depth studied the routing issue of the three networks and gotsome results. The major works include:(1) In DTMSN, existing routing researches assume that nodes are alwaysirrationally open in the working state. Based on the irrationality of the assumption, weproposed a new protocol, Periodic Sleeping-based Data routing Protocol (PSDP).Existing relevant researches consider about the compromise between data deliverysuccess ratio and data transmission overhead. Higher data delivery success ratio isobtained at the expense of node energy, so that the network lifetime is dramaticallyreduced. PSDP trades off between node energy consumption and opportunisticconnectivity, introducing periodic node sleep mechanism to save node energy. Thesleep time is decided by node data transmission probability and the distance from nodeto sink. In periodic sleep mechanism, PSDP acquires a long lifetime, acceptable datadelivery success ratio and transmission delay. In the longer lifetime, PSDP can gathermore data. (2) In Mobile Social Network (MSN), we proposed Hot Area-based RoutingProtocol (HARP). Due to certain social characteristics of MSN, the network nodesmove regularly. We can take advantage of the social characteristics and mobileregularity in data transmission and routing research. According to the hot area with theaggregated nodes and node mobile regularity, HARP gives each node a parameter calledregional access frequency, which shows the activity of the node in the network. Thenode with higher regional access frequency is more active, that is, the node has higherprobability to meet the target node. For selfish behavior of nodes in the network, weproposed HARPS (HARP with Selfish nodes) protocol. In HARPS, nodes will decidewhether or not to forward the data on their respective contributions to encourageforwarding data.(3) In VANET, we proposed Congestion Adaptive Trip Routing Protocol (CATP).For existing vehicles route planning solutions cannot adapt the real-time trafficcongestion, CATP protocol dynamically optimizes the traffic routes by gathering thetraffic information in the network. Without the assistance of the roadside infrastructure,the new protocol helps people to optimize the traffic route and improve the trafficefficiency by gathering the respective average pass time and average residence time ofthe road segments, estimating the road traffic conditions and then calculating newroutes.