Linear dynamic adaptation of the BW granularity allocation for elastic optical OFDM networks

In this paper, we consider the impact of spectrum fragmentation along the optical single/multipath routing transmission on the efficiency of the elastic optical network (EON). Using O-OFDM multicarrier transmission as a promising technique makes it possible to choose an adequate portion of available spectrum to satisfy the requested capacity. In a multipath routing scheme, distributing the light path request (LR) capacity over many paths results in increasing the network management complexity; meanwhile, using only single path scheme leads to an increase in the blocking probability ratio. In addition to these drawbacks, the spectrum fragmentation degrades the spectrum efficiency over the entire network. This work involves reducing the fragmentation effects by dynamically updating and controlling a suitable minimum bandwidth (BW) allocation granularity (g) for dynamic single/multipath routing over EON. We investigated the concept of “BW allocation granularity adaptation” based on dynamic change of g to replace using a fixed minimum bandwidth granularity over all candidate path(s) to serve the light path requests over multipath networks. We adopted a dynamic linear adaptation mechanism that is proportional to the optical link/path bandwidth fragmentation status. Simulation results show that improved performance over fixed minimum bandwidth allocation granularity with respect to the bandwidth blocking probability, throughput, and the number of path splitting.