Wireless Sensor Networks (WSNs) have been widely used in environment monitoring to collect useful information. Packet broadcasting is an essential function for establishing a communication path from sink node to an interested region of sensor nodes. Flooding is a simple broadcasting mechanism but consumes much power and bandwidth resources and raise the packet collision and contention problems. ZBP as a cellular based broadcast protocol can achieve energy efficiency and improve packet delivery rate by reducing the number of sensor nodes that forward query request as well as properly arranging broadcasting schedule, however it may face broadcasting failure caused by blank region of sensors. This paper improves ZBP by introducing an energy efficient recovery mechanism which recovers broadcasting when blank region interrupts the request forwarding. Compared with the simple over-network flooding recovery used by ZBP, our proposed protocol can reduce much energy consumption. Keywords- Sens...