Open Access

Optical Wireless Sensor Network System Using Corner Cube Retroreflectors

  • Shota Teramoto1 and
  • Tomoaki Ohtsuki1
EURASIP Journal on Wireless Communications and Networking20052005:930810

https://doi.org/10.1155/WCN.2005.39

Received: 18 March 2004

Published: 30 March 2005

Abstract

We analyze an optical wireless sensor network system that uses corner cube retroreflectors (CCRs). A CCR consists of three flat mirrors in a concave configuration. When a light beam enters the CCR, it bounces off each of the three mirrors, and is reflected back parallel to the direction it entered. A CCR can send information to the base station by modulating the reflected beam by vibrating the CCR or interrupting the light path; the most suitable transmission format is on-off keying (OOK). The CCR is attractive in many optical communication applications because it is small, easy to operate, and has low power consumption. This paper examines two signal decision schemes for use at the base station: collective decision and majority decision. In collective decision, all optical signals detected by the sensors are received by one photodetector (PD), and its output is subjected to hard decision. In majority decision, the outputs of the PDs associated with the sensors are subjected to hard detection, and the final data is decided by majority decision. We show that increasing the number of sensors improves the bit error rate (BER). We also show that when the transmitted optical power is sufficiently large, BER depends on sensor accuracy. We confirm that collective decision yields lower BERs than majority decision.

Keywords

corner cube retroreflectoroptical wireless sensor networkcollective decisionmajority decision

Authors’ Affiliations

(1)
Department of Electrical Engineering, Tokyo University of Science

Copyright

© Teramoto and Ohtsuki 2005

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.