Aug. 2, 2008 The ideal of affordable wireless broadband for all, and as an added bonus better quality services in urban areas, is a lot closer thanks to recent advances made by European researchers.
The next generation of broadband wireless networks is set to be simpler, cheaper for both operators and consumers, and more efficient than current technology permits. This is due to the innovative use of relay stations to boost the signals from base stations.
The FIREWORKS project will deliver fourth-generation (4G) broadband wireless access (BWA) systems to remote communities despite difficult terrain and low population densities.
In cities, where large buildings and thick walls can block or interfere with wireless signals, relays are a cost-effective and easy to deploy way of boosting reception to the end-user.
You the MAN!
The EU-funded project concentrated on OFDMA (Orthogonal Frequency Division Multiplexing Access) based networks and specifically those designed for BWA, particularly wimax and wifi. OFDMA networks have different characteristics and deliver signals in a different way to traditional fixed-line and cellular networks. OFDMA is already in widespread use and the technology will continue to be used for next-generation networks.
WiFi local area networks (LANs) are familiar to most people, with ‘hotspots’ where anybody can connect to the internet via laptop to be found in airports, cafes, hotels and other public areas all over Europe and internationally. The next evolution of WiFi is Mesh WiFi, where the individual hotspots are seamlessly linked together to form larger networks. WiMAX is designed to provide much wider coverage, which in a city would be a metropolitan area network (MAN).
“Relay stations are much smaller than base stations and are much easier to deploy – they can be fixed onto lamp posts for example,” says FIREWORKS technical manager Dr Antonis Valkanas. “They also should only cost around one-fifth of the price, as the intelligence is in the base station and, unlike base stations, they do not require a directed backhaul connection to the internet.”
FIREWORKS’ systems will also be able to provide, for the first time, seamless operation between WiMAX and WiFi networks, so somebody on the move with a mobile device or laptop will not notice the switch from one to the other.
Exploiting the overlap
One of the main challenges facing the researchers was the problem of how to maximise the gain from overlapping transmissions. The information can be accessed from either the relay or the base station at any one time, or by simultaneous transmissions by both of them.
The project was able to deliver new algorithms – small software packages – which ensure that, whatever transmission protocol is used, the best combination and clearest reception is assured.
With this problem solved, it is possible to extend the range of networks into previously inaccessible areas, whether due to high cost or rough terrain. It also is now possible to boost reception in urban blackspots by positioning relays where base stations are not feasible.
While the main benefits of FIREWORKS are not likely to be felt until the next generation of BWA networks start rolling out in Europe, from 2010, a prototype system has been developed to prove the viability of the relaying concept.
ROCKET, son of FIREWORKS
In fact, so successful was FIREWORKS that the EU has agreed to fund a follow-up project with the same core consortium.
Project ROCKET kicked off in January 2008, and will be both taking the techniques used in its predecessor forward and looking into other areas only previously touched on, such as the most efficient use and allocation of spectrum for BWA services.
The systems developed in ROCKET will conform with the latest BWA standards, including 802.16m, which are now going through the IEEE (the international engineering standards body) approval process, and so will have a shelf-life of many years.
From hop to hop-hop
The main focus of the project, though, will be to expand the scope of relay coverage from the single hop of FIREWORKS – one base station to one relay station – to a multi-hop configuration with one or more base stations sending signals onto to relay stations which can then retransmit to other relay stations. This will require a lot more work on the base-band and protocol layer to ensure what could be several different signals being combined into the best possible signal for the end-user.
While the work being done is highly technical, the end result will simply mean high-quality, low-cost wireless broadband access virtually anywhere in Europe, and eventually the whole world.
FIREWORKS was funded by the EU’s Sixth Framework Programme (FP6) for research. ROCKET is being funded by FP7.
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