WIK Working Paper in-building infrastructure: “Fibre needed to reach gigabit targets”

WIK study

New German telecommunications regulation §145 TKG defines in-building infrastructure deployment and sharing conditions. Its purpose is to support incentives for network operators to invest in and extend very high capacity access networks. A recent study by WIK, concludes that current in-building cabling cannot support the Government’s gigabit targets…


A Working Paper from WIK (Wissenschaftliches Institut für Infrastruktur und Kommunikationsdienste GmbH) provides an overview and technical comparison of the different in-building network installations and technologies predominantly available in Germany. This has been done in order to assess which are capable of ensuring 1 Gbps delivery (down- and upstream) to the end user. In this context, WIK has analysed the identified technologies implications on promoting open access to the building and, therefore, competition among network providers.

WIK’s research indicates that fibre cables are absolutely needed to reach gigabit targets set by the German government. According to the Working Paper

“Opening up the building for competition through physical unbundling should not be the exemption but the rule, yet these copper-based networks are not capable to achieve that. Existing in-building cabling (copper or coaxial cables) cannot support the - even if competition practices of sharing in-building cabling would be commonplace.”

WIK also stresses the importance of setting binding standards for cables and cable routing pathways in the deployment and renovation of in-building infrastructure. “They not only make the require investment more predictable but also facilitate upgrade of the in-building infrastructure to very high capacity networks (VHCN) and ultimately increase their adaptability to future developments. A round table of stake holders could define those standards.” Uncertainty regarding the extent of to which end-customers can be accessed and at what cost may negatively impact investment decisions on FTTH deployment.

Comparing in-building technologies

  • Copper with XG.FAST

Twisted copper pair cabling currently accounts for more than 70% of active inhouse cabling connections in Germany. Shared use of existing inbuilding copper cables comes at the cost of lower signal quality. With copper pair cables, competition (through physical unbundling) and symmetrical gigabit speeds may be attainable and these can be pursued separately - but not together.


  • Coaxial cables

Coaxial-based DOCSIS accounts today for roughly 70% of ‘homes-passed’ and 25% of ‘homes activated’ in Germany. While quality loss is not an issue, physical unbundling coaxial cables is only possible to a limited extent, under specific circumstances and with constrained results. Unbundling coaxial cables requires individual coax cables - an in-building cabling topology which is uncommon in German residential units.


  • Fibre optic in-building cables

Deployed in a Point-to-Point topology, these can reliably deliver symmetrical gigabit speeds to the end user, according to the Working Paper. “This future-proof technology does not present any of the problems and restrictions faced by the aforementioned copper-based in-building infrastructure,” according to the study. WIK does point out that the advantages may rapidly disappear if a Point-to-Multipoint topology with cascade splitters is used for fibre deployment.

Download the WIK Working Paper “In-Building Telecommunications Infrastructure”, which also examines topologies, safety requirements, competitive aspects and more.