BeamStar: A new low-cost data routing protocol for wireless sensor networks

Deployment of large-scale sensor networks calls for low-cost sensors and energy efficient routing schemes. The recent advances in light-weight Operating Systems, VLSI technologies, and wireless communications have greatly reduced the size and cost of wireless sensor devices. However, delivering sensed data to base stations, both reliably and energy-efficiently, is still a challenging problem. Scalable, energy-efficient, and error-resilient routing schemes are needed for such networks, with minimum requirements on sensor nodes. In this paper, we present a base station-assisted, location-aware routing protocol, which we call BeamStar, for wireless sensor networks. We make a major paradigm change by shifting computational intensive and energy consuming routing control overhead front sensor nodes to base stations. In BeamStar, each base station uses a directional antenna with power control. We show that these two capabilities are sufficient for each sensor node to determine its location, and the local location information is sufficient for power-efficient routing. Therefore, sensors are relieved of control and routing burdens, such as maintaining clusters and exchanging control information, yielding substantial energy savings. In addition, each data packet is forwarded in a constrained, loop-free mesh towards the base station, making data delivery robust to sensor failures and transmission errors. The proposed routing scheme is suitable for large-scale, dense sensor networks monitoring rare events.