Research On Adaptive Routing Algorithm Of Hybrid FSO/RF Network

Free space optical which takes the laser as the transmission medium has directive signal and centralized energy. It does not have the same frequent interference and the near-end crosstalk, moreover, as the physical layer transmission facility, any exiting transport protocol like TCP/IP may superimpose easily. FSO communication has many advantages, for example, high bandwidth, strong interference immunity, simple installation, no need frequency examination, and so on.FSO has very big attenuation under the foggy day, but RF having the low bandwidth is less vulnerable to the fog, so we can use it as the backup link. Using different characteristics of FSO and RF, we can construct high reliability FSO/RF composite network system. In this composite network, how to achieve the optimized routing algorithm and the highly effective link switching, which has a big reference value to the design and implementation of FSO.In this article, first we discussed the route issue in the FSO network, then introduced four kinds of different routing algorithms. We take average delay as the primary evaluative criteria, then compared these algorithms through the simulation, at last we obtained the Minimum Hop Count With Load Balancing Routing Algorithm.MHLB algorithm has the following features:1. Restriction of hops2. Considering the load balance of communication traffic on different paths.We also introduce specifically the adaptive dual-switching model of the link, and analyse the ideal link switching conditions, thus ensure the high availability of FSO/ RF hybrid network.Finally, we simulate the MHLB algorithm on MATLAB platform. The result demonstrates that the MHLB algorithm is much better than other routing algorithms in some aspects such as average retardation, packet loss rate and soon.