Addressing the backhaul challenge to support mobile data demands

18 October 2011 | John Hibbard


New technologies could offer the solution to some long-standing difficulties.

Juniper Research recently reported that operators will need to spend $840 billion over the next five years to overcome the bottlenecks in the backhaul network to support mobile data demands. The report says that fibre and microwave will dominate with microwave having 60% by 2016. However microwave has some limitations, namely the availability of spectrum.

There is something I have been itching to talk about for some time, but it has been kept under wraps until now. It is a project I have personally associated myself with because of its clear potential. By coincidence, Attochron, a company involved in this area, decided to make its development public at the same time as the Juniper report so I can talk about it. Many of you will recall that a decade ago, it was thought that free space optical (FSO) links could be the way to service short-haul requirements. FSO systems involve eye-safe optical beams which are streamed through the air from a "telescope" to a detector. With no spectrum licensing issues and fairly simple devices, this looked like a promising development.

You may recall companies such as FSO Terabeam and fSona. However they have been less successful than was hoped due to the greatest challenge for FSO which is the weather and clear air ‘turbulence’. In the weather issue, fog is a big concern as the size of the water droplets is such as to create substantial fading, reducing the potential data rate and link availability.

Attochron has developed a different technology involving ultrashort laser pulses. The transmitting laser is modulated with femtosecond pulses and with some clever sequencing the company seems to have found a way to substantially reduce the attenuation in all weather conditions. After numerous lab experiments, they have now completed the field trial which confirmed the theory.

At this early stage of development they are looking at about 3Gbps over 3km with 99.99% availability under a normal range of climatic conditions. The CEO of Attochron, Tom Chaffee, tells me that with further development 100Gbps over 10km seems quite possible. Whether this represents a significant contributor to meeting the needs for backhaul over the coming years, only time will tell but it is nice to see the development of new technologies to provide alternatives to address some of the pressing concerns within our industry.

Jon Hibbard is CEO of Hibbard Consulting. He can be contacted at jhibbard@bigpond.com