Routing in Degree-Constrained FSO Mesh Networks

This paper addresses the routing problem in degree-constrained free-space optical (FSO) mesh networks. FSO mesh networks are emerging as broadband communication networks because of their high bandwidth (up to Gbps), low cost, and easy installation. Physical layer topology design of degree-constrained FSO mesh networks has been studied in a recent communication [1]. In this paper, we propose four different routing algorithms, and evaluate their performances through simulations for a number of FSO mesh networks with different topologies and nodal degrees. The performance parameter against which we evaluate these algorithms is the mean end-to-end delay. Our proposed least cost path (LCP) routing algorithm, which is based on minimizing the end-to-end delay, is considered as the bench mark. The performance of each of other three proposed algorithms is evaluated against the bench mark. Our proposed minimum hop count with load-balancing (MHLB) routing algorithm is based on the number of hops between the source and the destination node to route the traffic. Simulations show that the MHLB routing algorithm performs best in most cases compared with the other two. It results in minimum average delay and least blocked traffic.