# A Dependable Localization Algorithm for Survivable Belt-Type Sensor Networks
## 2 Topological Modeling
### Model Requirements  
When deploying a wireless sensor network, if an aircraft is utilized to randomly distribute the anchor nodes, this may cause some nodes to be closely adjacent or overlapping, resulting in waste of resources and making many unknown nodes unable to be located. We use the packet structure model as the research basis, considering the characteristics of belt-type networks and the formation mechanism of the regional nodes when designing the topology. Grouping nodes in the network can improve the efficiency of communication channels and effectively control the resources occupied by the activity. The packet structure model is a common application object in sensor networks which is also the basis of an effective node deployment. The network topology is shown in Figure 1. In belt-type sensor networks, the normal nodes are usually placed along the edges of the coverage area, which makes it look like they are all in an extended line. For the sake of convenience, the nodes have the same information processing and communication capabilities in our model. Each type of node has its own sequence label (ID). The spatial distribution of nodes conforms to the following two principles: first, all nodes in the network are in the coverage of the whole detection area; secondly, in each sensor node group, the central node automatically becomes the group center, and the rest of the sensor nodes in each group can be covered by the central node of this group. The source node is a network node that acts as a sender to transmit the original packet. We name it \"Source\" for short. Sink, also known as \"sink node\", is responsible for connecting the sensor network to other networks. Normally, it can be considered as a gateway. The node with relay function is named as the \"relay node\". They are able to transmit data and information in a wireless, multi-hop manner. The beacon node is also known as an \"anchor node\" which belongs to a node that already knows its own position. In belt-type sensor networks, the communication between a sensor node and a monitoring base station should be executed through a relay node in the multi-hop way. Therefore, the closer the node is with the monitoring station, the more data it needs to forward. After operating for a long time, the network can easily form a \"hot zone\" that increases the burden of the whole network. The energy consumption is increasing quickly as well [9; 30]. Neighbor nodes near the base station are prone to \"empty energy\" phenomena. The emergence of the hot zone makes the number of nodes (near the base  
Figure 1: Adiagram of the network topology. station) continuously accumulates, and the activity occupies a large amount of the communication bandwidth. The calculation ability of the node is severely reduced, which can cause the rate of packet loss to rise. Therefore, the location valid information cannot be effectively passed and tested, and the positioning accuracy is finally affected. The network of nodes loses communication and computing power, which can easily cause the network down and positioning failure. To study the problem more effectively, we assume that:  
1. The sensor nodes are distributed in a wide rectangular area (length is \(L\) and width is \(M\), \(L>>M\)). The central gateway node is located in the middle of the strip area, and the sink node is located at the left side. The communication between the sensor node and the gateway node adopts the multi-hop mode, and the communication radius of the node is \(R\). The distances between most sensor nodes and base stations are greater than the \(R\) of the nodes themselves. The nodes in the group can communicate directly with the sink nodes, and the communication distances between the intergroup nodes are one-hop. At this point, the sink node and the source node communication radius should be greater than the length of the group (shown in Figure 2). 2. Each sensor node has a unique ID, and they can carry out information perception and collection independently.