Diversity analysis of free-space optical networks with multihop transmissions

Diversity analysis of multihop free-space optical (FSO) transmission shows the efficiency of this scheme to mitigate atmospheric turbulence. The significant performance of serial relaying is fundamentally a consequence of the distance-dependent channel variance. This prompts us to further investigate the requirements of different FSO networks to achieve a given diversity order. In other words, we aim at converting a network with multiple source and destination pairs to serially relayed transmissions. This indeed requires assisting nodes and reasonably efficient routing protocols. Besides presenting diversity analysis of multihop FSO transmission, this paper investigates how the number of relay nodes scales in terms of the number of source-destination pairs with respect to the geometry of the network and the required diversity order. Moreover, it proposes an optimal routing strategy for specific FSO networks with predefined placement of relay nodes.