The project FTTX-PLAN aims at the development of innovative methods and tools for planning broadband access networks based on mathematical models. These tools should enable network operators to decide upon planning and design issues by providing specifically tailored analyses.

Research carried out at ZIB comprises the development of mathematical models and methods for the design of such networks. In particular, various aspects of the problem shall be taken into account, such as technical and economic factors, where currently available tools include only single aspects.

Increasing use of new broadband communication services requires broadband connections between subscribers---industry, public administration, and private homes---and the world wide communication network. Access networks based on fiber optic technology, such as Fiber-to-the-Curb (FTTC), Fiber-to-the-Building (FTTB), and Fiber-to-the-Home (FTTH) make it possible to provide such infrastructure in the near future.

However, the construction of such networks requires major investments and therefore a strategic planning, which fits the specific constraints of a given scenario. A number of aspects have to be considered, such as existing infrastructure, available technology, the expected number of subscribers as well as services to be delivered, geographical constraints and last but not least the cost for constructing and operating the network.

The main goal of our research is the optimization of structures and configurations of fiber optic networks, bearing these constraints in mind.

To this end, ZIB is designing mathematical models for the main tasks that arise in the strategic planning of FTTx networks. These models shall incorporate the specific transmission technologies and structural characteristics of optical networks in different levels of detail. Also, the underlying mathematical structure of these models as well as their algorithmic properties are studied. To allow for efficient practical solutions new valid inequalities and algorithmic approaches shall be identified. As a result, new algorithms will be designed and implemented to solve the initial problem, up to scales that are relevant in practice.

Evaluating the developed methods, reviewing surveys are carried out in cooperation with all partners. Here, reference networks are optimized and the different alternatives for technologies are evaluated. The goal is to analyze and improve the considered approaches, models, and methods on the one hand, and to compare the different available network architectures on the other.