The Relay Area Problem in Wireless Sensor Networks

Wireless sensor networks often combine many-to-one traffic flows with multi-hop communication. This leaves them vulnerable to routing holes where empty spaces or voids inside the network area cause problems with routing. Large voids prevent traffic flowing through them and require nodes to calculate routes around the holes. In this paper, we discuss what we call the relay area problem. This is when small empty spaces in the network cause routes to become less direct which increases latency and reduces energy efficiency. Our analysis shows that it is extremely difficult to prevent these small holes existing inside the network. However, they significantly impact the network´s performance. We show that, even in dense networks, nearly 20% of the nodes have the relay area problem which increases the latency of any packet passing through them. Latency can be increased by almost 15% as a result of the problem.