Feature Stories - A super-fast network for the multimedia home
For many years, Wi-Fi has been the most widely used home networking solution, but even the latest 802.11n standard is unlikely to be able to meet future demands by itself, despite offering data rates in excess of 100 megabits-per-second (Mbps). In a future home, different occupants may want to stream different high-definition television (HDTV) channels or stored videos to different rooms, while at the same time someone may be playing a 3D game and someone else using a telepresence service to communicate with relatives abroad. Much higher data rates will be needed if several different data-intensive services are to work together simultaneously. 'Wi-Fi will undoubtedly play a role in future home networks… but it isn't the only solution,' says Jean-Philippe Javaudin, a project manager at Orange Labs, a division of France Telecom. Mr Javaudin coordinated the EU-funded 'Home gigabit access' (OMEGA) project, a large collaborative initiative involving 21 companies, universities and research institutes across Europe that demonstrated how different wired, radio and optical communications technologies can be used to create a hybrid network for high-speed communications in a home environment. They developed new optical solutions from scratch – using standard LED ceiling lights to transmit data, for example – and they implemented a new standard, now set to be used commercially, to ensure all the different technologies work together seamlessly and transparently for the end user. 'On the one hand, in a future home people will want to transmit large amounts of data locally, playing high-definition videos, for example from a network storage device in their basement, on the TV in their bedroom. On the other hand, they will use more data-intensive internet services… Cable networks can now bring internet to their front door at 100 Mbps and will soon be running at 1 Gbps,' Mr Javaudin notes. 'We wanted to bring the home network up to that speed.' One network, multiple technologies Starting at the home gateway where the internet connection enters the home, the OMEGA team studied how best to provide high-speed connections to all devices in the building. Within a single room, the researchers demonstrated how radio and optical solutions can be used in combination to transmit data for different services wirelessly. First, they developed a cutting-edge 60 gigahertz Wi-Fi transceiver with a demonstrated capability of several hundreds of Mbps at a range of more than 15 metres. Next, they developed an optical solution using infrared light – similar to how a TV remote control works – to transmit data at up to 280 Mbps over a distance of 10 metres. However, unlike a TV remote control and some other infrared technologies, the OMEGA system does not only provide point-to-point, unidirectional communications, but bidirectional line-of-sight communications between multiple devices to create an infrared network – one of the first of its kind. The project team also developed a groundbreaking optical solution using visible light. In a world first, they sent data using LED ceiling lighting of the kind becoming increasingly common in many homes due to its low power consumption. By flickering the lights on and off at a rate of 10 megahertz – too fast for the human eye to notice – the lights are able to double as a data broadcasting solution. At the project's final event at Orange Labs in Rennes, France, in March, the team aggregated the output from four video players into an Ethernet stream and modulated the data stream onto the electrical current driving 16 LED lights, allowing four different high-definition videos to be broadcast simultaneously at 100 Mbps. 'The technology is a novel unidirectional, point-to-multipoint solution for broadcasting data, which also doubles as a lighting source,' Mr Javaudin says. Because light and high-speed radio cannot pass through walls – due to the high frequencies used – the OMEGA team incorporated 'Power-line communications' (PLC) into their overall architecture. PLC, which uses standard electrical power wiring to transmit data, is already in use commercially. However, the OMEGA researchers implemented an enlarged frequency band of 0-100 MHz, compared to up to 30 MHz in use presently, with the aim of reaching transmission speeds of up to 1 Gbps. Significantly, from a commercial point of view, they made the system backwards compatible with the HomePlug AV/IEEE 1901 standard. They also made it compliant with existing electromagnetic compatibility regulations below 30 MHz and will make sure it will also be compliant with regulations to come in the upper band. Convergence towards commercialisation Tying all the different technologies together, and ensuring they function seamlessly and without interference, is the 'Inter-MAC' layer, which ensures convergence between different networks and devices. Inter-MAC intelligently adapts and manages transmissions across technologies, making devices aware of each other and mitigating interference. It is crucial to making home networks transparent and easy to use for end users who, the project partners envisage, will be able to bring a new device home, turn it on and have it instantly connected to the most suitable communications channel available. 'The inter-MAC layer always takes the best possible combination or cascade of standalone connections to transport the flow to the terminal with the target quality of service (QoS). We have even demonstrated that a laptop with the Inter-MAC software can be an extender itself, which is basically a network element able to extend the coverage in the home thanks to one or multiple technologies. This paves the way for future pervasive capillarity managed home networks,' says Martial Bellec, the OMEGA technical manager at Orange Labs. The project's Inter-MAC research has fed into the development of the IEEE P1905.1 standard that will soon be used commercially. 'We are planning to launch two spin-off companies from the OMEGA project – one in Italy and one in Germany – which will develop products implementing the new standard,' Mr Javaudin explains. 'It is likely that products with Inter-MAC-like functionalities will be on the market next year.' The first likely application for Inter-MAC technology will be to provide redundancy between PLC and Wi-Fi connected devices. 'At present, people have a set-top box for HDTV connected with Ethernet or PLC from their home gateway. We are looking to add Wi-Fi connectivity to that so that if there is some interference on the first connection, the other will automatically step in and provide a back up. The network will automatically switch between the best communications technology available at any given time,' Mr Javaudin says. From there, the partners plan to use Inter-MAC not just for point-to-point communications, but for fully-fledged home networks. That application, Mr Javaudin says, could be in use commercially in homes in just a few years. 'The OMEGA use cases encompassed very advanced scenarios and the key was to find short-term business needs in them,' explains Mr Bellec. 'We now have a first example of a sustainable architecture for more complex use cases into the future.' The OMEGA project received EUR 12.41 million (total project cost EUR 19.13 million) research funding under the EU's Seventh Framework Programme for research (FP7), sub-programme 'The network of the future'. Useful links: - 'Home gigabit access' project - OMEGA project data record on CORDIS Related articles: - EU-funded project to deliver innovative Internet architecture model - Internet of the future could be up to ten times as speedy - Novel optical amplifier without the noise - Easy-build wireless networks