Gigabit data rates over copper telephone lines
The existing copper infrastructure is used to complete the access line to, and within, the building. To determine how 1-2 Gbit/sec data rates can actually be achieved in such environments, researchers from Fraunhofer ESK will be working with Lantiq and InnoRoute GmbH until 2016 as part of the FlexDP research project.
Achieving high access data rates requires utilisation of the higher frequency ranges on the phone lines. This is possible only if the copper line segment of the data transmission channel is relatively short. With this in mind, Fraunhofer ESK is analysing the channel properties within these high frequency ranges as part of the FlexDP project. Lantiq and InnoRoute will use the results of this work to eventually develop a reverse powered, flexible distribution point installed closer to the customers’ premises. Through a combination of research, implementation and testing, the partners are laying the groundwork for the practical application of FTTdp.
Measuring channel properties in the 300 MHz frequency range
VDSL2 uses frequencies up to 30 MHz. With the aim of achieving still higher data rates, Fraunhofer ESK is examining the use of frequencies up to 300 MHz. Apart from the transmission characteristics of the line, background noise and sporadic impulse interference are important factors that impact transmission speeds. Higher frequency ranges permit the deployment of new transmission schemes such as G.fast, which operates up to 212 MHz and is currently in the standardisation stage. By extending the currently used spectrum, data rates of up to 2 Gbit/sec are theoretically possible, but only if the channel characteristics are consistently taken into consideration.
In order to gain a realistic picture of the situation in Germany, Fraunhofer ESK researchers identified and measured the various types of cables used in the country and examined typical customer premise wiring installations. Based on this preparatory work and with new measurements in the 300 MHz extended frequency range, engineers will develop a simulation environment allowing them to recreate and test a variety of network scenario. Researchers will then be able to pinpoint early on any issues that affect high bit rate data transmission, thus paving the way for the development of reliable solutions. The know-how gleaned from this work will furthermore flow into future transmission system designs and installations.
Energy-efficient, flexible distribution points accelerate network build-out
Higher data rates with a hybrid network can be achieved on short lines. With G.fast, this equates to a maximum of around 250 metres. It also requires locations closer to the customer premises, a task made easier if the distribution points are not dependent on existing power lines and instead are reverse-power fed by the customer’s telephone lines. That means the shoebox-sized distribution points must be extremely energy-efficient.
The major challenge of this remote power concept lies in the fluctuating loads placed on the network since each customer’s behaviour is usually different with respect to bandwidth usage and time of day. The hardware architectures and components that will be developed by Lantiq and InnoRoute must be as energy-efficient as possible, just like the transmission method itself, in order to deal with varying customer usage patterns. That means a single customer modem must provide enough power to operate the distribution point. Transmitter and receiver components also need the capability to dynamically turn on and off, which in turn results in dynamic changes to the crosstalk interference environment. This creates another challenge in developing algorithms for stable transmission in dynamically-changing scenarios. Fraunhofer ESK is also working on emergency operation concepts to compensate for power outages.
This project is being funded by the Bavarian Research Foundation.
The project partners:
Fraunhofer Institute for Embedded Systems and Communication Technologies ESK undertakes applied research geared toward new information and communication technology (ICT) processes and methods. www.esk.fraunhofer.de/en
InnoRoute (Germany) is adapting its FlowEngine packet processor to meet the special challenges associated with G.fast distribution points. This involves relying on the company’s experience in cost-efficient packet processing and design space exploration methods. InnoRoute is also researching an SDN-based solution for controlling access network quality of service and is developing an IPv6 router concept. www.innoroute.com
Lantiq is a provider of semiconductor solutions powering broadband, next generation networks and the digital home, specialising in broadband communications, including analogue, digital and mixed-signal ICs, as well as complementary comprehensive software suites; www.lantiq.com
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