Research On Resource - Constrained Wireless Ad Hoc Network Routing Algorithm

Wireless ad-hoc network is a wireless distributed network with uncentralized, multihop and infrastructureless, so it can be widely deployed in special area which wired network can not cover or in business, military and disaster relief scenarios. Although the extensive popularization and deep research on wireless ad-hoc networks provide technical support for data transmission in a mobile environment, the network is not connected for a long time caused by devices mobility, coverage density variability, limited power, smaller buffer resources and wireless devices communication interference. Two most important issues should be considered to guarantee message delivery in wireless ad-hoc network:routing protocols and efficient buffer management strategy. At the same time, lower transmission bandwidth, limited power, and smaller buffer resources of nodes should be taken into account accordingly in routing decisions. Therefore, in this thesis, we are focused on features of data transmission in wireless ad-hoc networks with limited resources. The main achievements and contributions of our work can be summarized as follows:(1) To cope with the demands of multiple QoS and multipath of wireless sensor networks, a cost-aware multipath routing algorithm (CMPR) is proposed to obtain multiple paths for mobile wireless sensor networks. Based on MP-OLSR routing algorithm, CMPR dos not gain routing paths by the predefined weight values of links and nodes. The proposed algorithm simultaneously considers the real-time residual energy of nodes and the real-time queue length of nodes in routing decision, then gains several node-disjoint optimum multipaths though the Dijkstra algorithm that we improved. Furthermore, the scheduling strategy of priority-based multimedia data flow is presented. Then, the routing algorithm is described, and the correctness and time-space complexity of CMPR routing algorithm are analyzed. Experimental results based on the Qualnet simulator show that the CMPR routing algorithm can evidently achieves better performance in terms of the balance of node energy consumption, the ratio of received packets, the end-to-end transmission delay and the delay jitter.(2) To make up for the lack of traditional WiFi communication mechanism only supports broken-point continuingly-transferring communication between both parties, a shared video on-demand streaming system (SVSS) in WiFi-based mobile opportunistic networks is designed and implemented. The proposed SVSS routing algorithm can upload or download data from the "break-point" and also receive one file from different sources. At the same time, the architecture and routing algorithm of the SVSS are described, and the correctness and time-space complexity of SVSS routing algorithm are analyzed. Experimental results in the real world scenarios demonstrate significant performance benefits in terms of information diffusion between SVSS routing algorithm and traditional WiFi which only support broken-point continuingly-transferring for two parties. Compared with WiFi communication, the SVSS routing algorithm significantly increases the amount of packet forwarding, reduces the equipment power consumption and has strong practicability in mobile environments.(3) To solve the problem of limited energy and buffer resources of mobile nodes for opportunities network, a practical routing algorithm based on WiFi for resources-constrained opportunistic networks (ONRWF) is designed. ONRWF routing algorithm contains delivery prediction which can decide next hop routing by comparing the prediction of future meeting time of all nodes. Scheduling policy reassigns the priorities for each message and determines which messages should be transmitted when two nodes need to exchange messages. In the strategy of buffer management, considering the characteristics of RWP mobility model and multi-level data, the scheduling policy of ONRWF aims to improve message delivery of high priority, and the proposed drop policy focuses on improving the efficiency of buffer space. At the same time, the routing algorithm of ONRWF is described, and the correctness and time-space complexity of ONRWF routing algorithm are analyzed. Experimental results in the real world scenarios demonstrate significant performance benefits in terms of information diffusion between ONRWF routing algorithm, WiFi and SVSS routing algorithm. Experimental results demonstrate significant performance benefits in terms of message delivery ratio, average energy consumption and average queue length.(4) To verify the correctness of SVSS routing algorithm and ONRWF routing algorithm for opportunistic networks, two prototype systems named SVSS and ONRWF are designed and implemented based Android smartphone operating system platform. Moreover, the architecture of SVSS and ONRWF are discussed deeply, and its running processes are analyzed. At last, experimental results based on the real campus scenarios show that the prototype systems implemented in the thesis are correct and efficient.This project is funded by the National Natural Science Foundation of China named "Research on theories and methods of temporal-space dynamics about propogation of malicious code in mobile wirless sensor networks" (No.61173094). In the thesis, we are focused on features of data transmission in wireless ad-hoc networks with limited resources. Three routing models are constructed and implemented, which can provide theoretical and technical support for the well-designed data transmission performance routing study of wireless ad hoc networks. The results also have certain practicability in mobile wireless environments.