Studies On Quality Of Service Control Problems In Wireless Sensor Networks

With regard to wireless sensor networks (WSN), which are data centric and aiming at event detecting, how to optimize the network performance with the proper application-specific QoS (Quality of Service) is the important problem to be discussed. Focused on the specific QoS problem in wireless sensor networks, some important research results are as follows:1. Node cross-layer design and modeling based on WSN characters. The specific characters in WSN determine that traditional network models are not applicable. Referring to the traditional network models, a cross-layer model of nodes is proposed with OPNET network simulation tools. The model improves and optimizes the existing network layers, incorporates and reduces redundant network layers, so as to optimize algorithms, decrease data buffer and make algorithms easy to control.2. Propose the conception of event delay. And then a mechanism of classific QoS algorithm is proposed. The application target of WSN is to detect events, so it pays more attention to the QoS of colony data packets. The proposed mechanism considers the different event delay requirements, dynamically adjusts the classific QoS parameters of each event to distribute the network resources and meet the application requirement.3. Design the WSN specific QoS mechanism based on node density domination. The number and range of power-up nodes are the specific QoS problems of WSN. Focus on these problems, the node density domination mechanisms based location information and local hop information are proposed. The location information based mechanism proposes the density domination algorithm of rectangular, circular and various elliptical areas, and designs the corresponding dynamic adjusting mechanism imposing the node relative location information. The local information based mechanism realizes the equivalent rectangular area density domination according to the hop information of neighbor nodes. This algorithm also gives the dynamic adjusting mechanism.4. Design and realize the prototype system according to the QoS requirements of WSN. With reference to the existing systems at home and abroad, the hardware platform of WSN node is finished, and the Linux C style operating system SOS is successfully ported to the hardware platform. Based on the prototype system, the event-delay based QoS mechanism is experimented on the prototype system.