Deployment Strategies for Protected Long-Reach PON

The mass deployment of fiber access networks is probably the most important network upgrade strategy for operators over the coming decade. Next-generation networks, and in particular the long-reach passive optical network (LR-PON) solution, aim to increase the long-term economic viability and sustainability of fiber-to-the-premises (FTTP) deployment. The LR-PON solution achieves this by minimizing the number of nodes and the amount of electronic equipment required within the network. Since an LR-PON replaces the metro backhaul network, which is usually a protected part of the network, protecting the long-reach part of an LR-PON against failure becomes a critical issue that needs to be taken into account. In this paper, we introduce a novel protection mechanism which, by spreading the load generated by a node failure over the network, can significantly reduce the overall protection capacity required. We then present a practical FTTP deployment scenario based on our protected LR-PON architecture for a European country. The problem is modeled using integer linear programming, and the optimization results, obtained using a real dataset provided by a national operator, show that a small number of metro/core nodes can provide protected connection to FTTP users. By applying a detailed cost model to the outcome of the optimization, we are able to show that our LR-PON deployment strategy, which minimizes the overall protection capacity, rather than just minimizing fiber distances in the LR-PON, can significantly reduce costs.