A power-preserving broadcast protocol for wireless sensor networks

Broadcast presents a special challenge for Wireless Sensor Networks (WSNs). In situations such as time synchronisation or routing path establishment, broadcast messages must be securely transmitted to all nodes, but these messages may be attacked by adversaries. We consider the example of an adversary who launches a denial-of-service attack by forcing an intermediate node to repeatedly re-broadcast, draining that intermediate node's power reserves. We examine a solution to this attack that limits the number of message-relaying nodes in the network, thus reducing the amount of energy required to broadcast a message (thus reducing vulnerability to this attack). This paper presents a power-preserving broadcast protocol (BOPP) that uses a packet reception reliability metric. The reliability score is computed for every communication link in the network. BOPP then selects a set of repeater nodes that most contributes to a broadcast. The selection process is repeated whenever the score distribution changes.