Efficient parallel relaying FSO communications using rateless codes in horizontal terrestrial and satellite-to-ground scenarios

The reliability of FSO communications is severely limited by atmospheric conditions. Adding redundant communication channels, like parallel relaying, is a solution to achieve high reliability. Parallel relaying can achieve non-linear propagation and compensate for signal degradation by reducing the length of single hops, but at the cost of increased resource consumption. To optimize resource utilization, a parallel relaying configuration employing rateless codes (RCs) is proposed in this paper. Since different coded packets are transmitted over each parallel link, RCs achieve higher resource utilization efficiency and lower latency, compared to standardized packet duplication. A precise analytical framework is elaborated to calculate the average required resources for parallel relaying system with RCs under atmospheric turbulence channel. Evaluated in both horizontal terrestrial scenario and satellite-to-ground scenario, the proposed RCs scheme shows superior resource utilization efficiency under a dynamic atmospheric channel.