Multicast Performance Analysis Of Large Scale Wireless Sensor Networks With Obstacles

Recently with the development of Wireless Sensor Network (WSN) technology and the increase of the applications of wireless sensor networks, research on the wireless sensor networks has gradually got the focus from industry and academe. Due to the characteristics of the wireless sensor networks, such as large scale, limited transmission range, the transport ability of the whole network, denoted as the network capacity is attaining more and more attention. A better understanding of the network capacity can help better design the network and deploy the sensor nodes.There are plenty of works that analyze the network capacity for flat network regions with large amount of solid results. While in practice, the network region that the sensor nodes are deployed in may contain some obstacles, for example, in a mountainous area, the forest and a building. The existence of the obstacles is one of the biggest impacts on the network performance. Firstly, the obstacles will restrict the deployment of the sensor nodes, and the network topology will change in consequence. Secondly, the existence of the obstacles will damage the radio signals and intercept the communication between sensor nodes. There are two research topic regarding to these problems in wireless sensor network with obstacles. Firstly, what is the impact of the obstacles on the network capacity, including the size or the shape of the obstacles. Secondly, regarding to this impact, how to design effective routing mechanism of the communication to maximize the achievable capacity of the sensor network. We will discuss these problems respectively in the paper.Multicast transmission which incorporates both the broadcast and the unicast transmission is a frequently-used transmission style, and is more efficient compared to multiple unicast transmission, it is well applied in the multi-media and military communications. There are plenty of researches on multicast capacity of wireless networks under different models and different transmission technique to improve the multicast capacity which we will discuss in the paper later. In this paper, we will consider the multicast capacity in the sensor network with obstacles. The obstacles are modeled by dividing the network region into cells and pointing out the obstructed cells. The multicast capacity of the network is discussed in terms to the scale of the multicast group. Both the upper bounds and the lower bounds of the multicast capacity is discussed in the paper. An efficient routing mechanism is proposed to bypass the obstacle area and balance the network load. A concept of virtual destination node is proposed to help connect destination nodes which are departed by the obstacles. The upper bound order of multicast capacity can be reached by applying the proposed routing mechanism.