Cooperative Hybrid VLC-RF Systems for WSNs

In this paper, a cooperative hybrid visible light communication (VLC)-radio frequency (RF) wireless sensor network, which includes a transmitter (S) with a cluster of light emitting diodes (LED) lamps, a relay (R) and a destination (D), is taken into consideration. Specially, R is randomly located in the coverage of the LED lamps, D is randomly distributed out of the coverage of the LED lamps. Then, VLC is employed for S-R link and traditional radio frequency (RF) communication technology is adopted over R-D link. Moreover, both of decode-forward (DF) and amplify-forward (AF) relay schemes are considered at R to aid the data transmissions between S and D. Considering Nakagami-m fading over R-D link, and the randomness of the locations of R and D, the statistical characteristics of the received signal-to-noise ratio at D under both AF and DF relay schemes are characterized, respectively. After that, approximated analytical expressions for the outage probability of the considered system are respectively derived. Finally, simulation and numerical analysis are conducted to verify the correctness of our proposed analytical models.