Microsoft Word - Van der Wee_ACP_final

This paper studies the business case of migration from legacy FTTH networks like active star Ethernet and GPON towards NG-AON and TWDM-PON for a network provider, evaluating its techno-economic viability and suggesting possible improvements. Introduction and motivation It is clear that all-fiber networks are the future for telecommunications access. Although the current technologies, such as active star Ethernet or active optical network (AON) and gigabit passive optical network (GPON), are capable of offering significant speeds, ever increasing future demands will require higher, symmetrical bandwidths. Furthermore, the deployment of all-fiber networks requires high investments, mostly in the deployment of the passive infrastructure (up to 70% of deployment cost [1]), while the active equipment for lighting up the fiber only accounts for 30%. When however looking at the lifetime of both layers, the passive infrastructure is predicted to have a lifetime of 30 to 50 years, comparable to the lifetime of the traditional copper-based networks. The active equipment technology has a much shorter replacement period, e.g. 10 years. It is therefore mandatory to investigate the full longterm technology evolution and replacement when comparing FTTH investments. This paper will investigate the business case for a network provider (NP), responsible for installing and maintaining the active equipment, for an upgrade of two architectures: Next generation AON (NG-AON), migration from AON, and time and wavelength division multiplexing (TWDM) PON, migration from GPON [2]. NG-AON and TWDM-PON NG-AON (Fig. 1a) is the natural evolution of an AON, active star architecture in which the customer has already been connected by means of Ethernet switches (32 ports switches are used in the study) from the central office (CO) via an intermediate aggregation point at a remote node/cabinet. One of the NG-AON variations is to adopt WDM-PON technology which can be used to backhaul the existing AON active star architecture. In a migration towards a node consolidation strategy [3], the first level of (or legacy) COs in the current FTTH network will be closed down, and hence, the OLTs and other equipment in the CO must be relocated further to an aggregated central access node (CAN). In relation to the NG-AON solution, arrayed waveguide gratings (AWG, 1:40) are placed in the legacy CO locations to backhaul all the traffic and forward them to the CAN. In total, this NG-AON can serve up to 32x40 (1280) customers from one feeder fiber. The migration from the existing AON active star to NG-AON (WDM PON backhauling) architecture can be deployed smoothly without changing the fiber infrastructure in the existing distribution network. Some NP equipment in the existing AON architecture (e.g. optical network terminals (ONTs) and Ethernet switches) can be reused in the NG-AON. Fig. 1: Architecture changes for (a) migration from active star AON to NG-AON, and (b) migration from GPON 1:16 to TWDM-PON TWDM-PON (Fig. 1b) is a natural evolution of a TDM-PON in which the customer is connected to the CO by means of a power splitter (1:16). As TWDM-PON solution, we assume that 80 of the existing 1:16 TDM-PONs are gathered further in the network by means of a 1:80 AWG. In this way each TDM-PON has its own wavelength and serves in turn 16 customers in a TDM manner. In total, a TWDM-PON80x16 will serve up to 1280 customers from one feeder fiber. This paper will compare the migration costs of NG-AON and TWDM-PON, and indicate how OLT ONT ...