Location-free boundary detection in mobile wireless sensor networks with a distributed approach

Location-free boundary detection is an important issue in wireless sensor networks (WSNs). Detecting and locating boundaries have a great relevance for network services, such as routing protocol and coverage verification. Previous designs, which adopt topology-based approaches to recognizing obstacles or network boundaries, do not consider the environment with mobile sensor nodes. When a network topology changes, a topology-based approach has to reconstruct all boundaries. This study develops a distributed boundary detection (DBD) algorithm for identifying the boundaries of obstacles and networks. Each node only requires the information of its three-hop neighbors. Other information (e.g., node locations) is not needed. A node with DBD can determine whether itself is a boundary node by a distributed manner. The DBD approach further identifies the outer boundary of a network. Performance evaluation demonstrates that DBD can detect boundaries accurately in both static and mobile environments. This study also includes experiments to show that DBD is applicable in a real sensor network.