| Wireless Sensor Networks are composed of many smart sensor nodes which are small, withlimited processing, computing resources and limited energy. These sensors can be deployed in anAd-Hoc manner and self-organized into a system that monitor events in an area of interest andforward data back to a central node. Many sensor network applications, such as ocean monitoringand earthquake response systems, are designed to help human to have a more comprehensiveunderstanding of the physical world. As wireless sensor networks has great application potential andattracts more and more attentions, it needs to design high reliable and energy-efficient routingprotocols to provide QoS of the network.The limitation of the energy and computing capability of the WSNs poses great challenge todesign QoS routing protocols. This thesis does a deep research into WSN QoS protocol. In order tomeet the QoS requirement of WSNs and take advantage of the broadcast nature of the wirelessmedium, this thesis exploits a Grid-based QoS Opportunistic Routing (GQOR) protocol. GQOR isan opportunistic routing protocol based on virtual grid. With the help of location information, itdivides the network into virtual grid and it realizes the directed transmission towards the Sink nodeand avoids traffic flooding to the whole network to conserve energy by utilizing grid forward routingbased on congestion state. In order to provide a higher QoS guarantee, GQOR introduces delayprediction mechanism, speed prediction mechanism and energy balance mechanism into the routingprocess between virtual grids. And at the time the congestion control mechanism is proposed in thisthesis to further improve the performance of GQOR.The simulation results and the theoretical analysis results show that compared with thetraditional QoS routing protocols, the GQOR protocol can significantly improve the reliability,extend the lifetime of the network at very low cost of delay in the data transmission process. |
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