Energy-Efficient, Turbulence-Regime based Adaptive FSO Broadcast Systems

The need for digital multimedia has surged with advanced and affordable mobile devices. Offering multimedia via free space optical (FSO) systems is possible but doing so requires a lot of energy. Also, for optical wireless communication systems, signal strength degradation brought on by atmospheric turbulence is an unavoidable drawback. In this paper we present an energy-efficient turbulence-regime based adaptive FSO broadcast scheme, that optimally combines the turbulence-regime information at the receiver with a particular multimedia service (e.g., video quality profile) for adaptive scalable multimedia encoding of the broadcast content. The strength of turbulence at the receiver is obtained a priori based on rytov parameter at that location. Based on this information, in order to optimally use the base station power reserve the transmitter may decide to send turbulence adapted multimedia content quality namely, a fair signal strength instead of good/excellent for weak turbulence, good signal strength instead of excellent for moderate turbulence and excellent signal strength for strong turbulence . By incorporating the turbulence information in the multimedia encoding, the proposed scheme helps to achieve a better quality of experience and higher energy saving both in terms of base station power reserve and user equipment energy saving as compared to the pure quality maximizing scheme or fixed power allocation scheme. The simulation results also show that the churn rate is minimum in the proposed scheme.