Hybrid Radio and Optical Communications for Energy-efficient Wireless Sensor Networks

Abstract

A wireless sensor network (WSN) consists of a large number of networked sensor nodes deployed to sense and report a particular phenomenon to a base station. One of the main design considerations for WSNs is the energy consumption of the individual sensor nodes. Currently, most WSNs are radio frequency (RF) based, and communications account for a significant portion of the energy expended. The hybrid radio frequency/free space optical (RF/FSO) WSN is proposed to lower energy consumption. The RF and FSO link models used for the RF/FSO WSN are first discussed. Next, the energy expended by the sensor nodes for sensing, data processing and communications is modeled. These models are used to simulate the lifetime of the WSN. To investigate the energy efficiency of the RF/FSO WSN, an RF-only WSN is used for comparison. Simulations show that the average energy consumed by the nodes in the RF/FSO network is significantly lower than that of the RF-only network, thus increasing the lifetime of traditional RF-based WSNs.

Keywords:

• Free space optics
• Radio frequency communications
• Sensor networks

Additional information

Notes on contributors

Sashigaran Sivathasan

Sashigaran Sivathasan received his MSc (2001) and DPhil (2008) degrees from the University of London (Imperial College London) and the University of Oxford respectively. He is a Lecturer at Central Queensland University. His current research is in the area of wireless sensor networks. E-mail: [email protected]

Dominic O’Brien

Dominic O’Brien is a Professor of Engineering Science at the University of Oxford, and leads the optical wireless communications group. He gained MA(1991) and PhD (1993) degrees from the Department of Engineering at the University of Cambridge. From 1993–1995, he was a NATO fellow at the Optoelectronic Computing Systems Center at the University of Colorado. His current research is in the field of optical wireless systems. He is the author or co-author of approximately 150 publications or patents in the area of optics and optoelectronics. E-mail: [email protected]