Design and dimensioning of hybrid PONs

We investigate the greenfield deployment of hybrid time division multiplexing/wavelength division multiplexing passive optical networks, i.e., the optimized covering of a given geographical area by a set of cost-effective and properly dimensioned hybrid PONs. We first propose a three-phase optimization scheme. In the first phase, a p-center model is proposed to determine the best ONU clusterings and the lower-level passive distribution node equipment locations. The second phase takes care of the placement of the upper-level passive distribution node equipment and the third one, using the traffic demands, a mix of unicast and multicast requests, selects the most appropriate passive distribution node equipment, i.e., either an arrayed waveguide gratings or a splitter. We next merge the first two phases, leading then to a two-phase scheme. Computational experiments are conducted on two sets of ONUs, one with 128 and one with 512 ONUs. We compare the two- and three-phase schemes in terms of PON design costs. We observe that the two-phase scheme provides more cost-effective solutions. We also provide a sensitivity analysis with respect to several parameters in order to identify the number of ONU clusters that minimizes the deployment cost.