Optimization of survivable filterless optical networks exploiting digital subcarrier multiplexing

In aggregation networks, the traffic patterns resemble hub-and-spoke characteristics, with a few hub nodes connecting several leaf nodes to the outside of the networks. The use of traditional point-to-point transceivers in these applications results in many low-capacity devices at the hub nodes. Optical transceivers leveraging digital subcarrier multiplexing (DSCM) have recently been proposed to support point-to-multipoint transmission in the optical domain, allowing the use of fewer high-capacity devices at these nodes, thus significantly reducing both capital expenditure and operational expenditure. A high-capacity signal comprising multiple subcarriers is transmitted/received at the hub node, while each leaf node has only to transmit/receive the subset of subcarriers that are intended for it, enabling optimization of the type of transceiver used at each node. Broadcasting the optical signal using an optical tree to reach the different leaf nodes, coupled with the possibility of supporting failure survivability, requires developing algorithms to jointly optimize transceiver deployment and the underlying optical trees. This work proposes a novel integer linear programming model for optimizing the design of resilient metro-aggregation networks using DSCM-based coherent transceivers. Results obtained over two realistic mesh networks show that transceiver expenditures can be reduced by a figure between 23% and 44%.