Demonstration of how millimeter-wave (MMW) part of spectrum can be used for Internet access in developing world
Facebook’s efforts to connect the entire planet to the Internet continue after news emerged of its demonstration of a “record-breaking” data rate using millimeter-wave (mmWave) technology.
This technology is seen by many as a way of boosting connectivity speeds and capacity, but Facebook hopes to use it to connect areas where there is currently no Internet access.
Fujitsu and the Tokyo Institute of Technology for example achieved ‘world record’ transmission speeds of 56 Gbps in February, thanks to the use millimeter-wave (mmWave) frequencies located between 30-300GHz.That speed however was achieved in indoor tests across a distance of just 10cm.
Facebook on the other hand has revealed that earlier this year it had conducted tested a terrestrial point-to-point link in Southern California, and “demonstrated a record data rate of nearly 20 Gbps over 13 km with MMW technology.”
The demonstration took place on a mountaintop in Malibu, CA, and a building rooftop in Woodland Hills, CA, separated by a line-of-sight distance of 13.2 km.
Facebook engineer’s have concerned about making this technology as energy efficient as possible, because most parts of the developing world still lack traditional infrastructure and reliable power sources.
The researchers said they built a set of custom-built components, and were able to achieve the speed with only 105 watts of total direct current (DC) power consumption at the transmitter and receiver.
“The transmission used a bandwidth of 2 GHz, resulting in an overall spectral efficiency of 9.8 bits per second per Hertz,” said the researchers in a blog post. “To put this in perspective, our demonstrated capacity is enough data to stream almost 1,000 ultra-high-definition videos at the same time.”
The researchers believe that mmWave could be applicable in a number of connectivity solutions going forward.
“For example, it could be used as a terrestrial backhaul network to support access solutions like OpenCellular, or as a reliable backup to free space optical solutions such as the laser communications gimbal and optical detector in case of fog and clouds,” they wrote. “Ultimately, the point-to-point MMW radio link is expected to serve as the connection between a ground station and Aquila, our solar powered UAV. However, we still have several connectivity and technical challenges to resolve before the technology is fully ready for deployment.”
These challenges are not inconsiderable. For example terrestrial wireless links will have to be deployed on towers or structures in regions where there is intermittent or no electricity. This means that solar panels would have to supply the required juice.
It should be remembered that Facebook is also building a solar powered drone (Aquila), that will allow for Internet laser-beamed to unconnected parts of the world from 90,000ft in the sky.
“Our goal is for Aquila-to-ground links to support capacities in excess of 30 Gbps over 30-50 km,” said the researchers. “In addition, since Aquila is a long-endurance, solar-powered UAV, there are strict size, weight, and power consumption constraints on the communication payloads hosted on the aircraft.”
The next step for the Facebook team involves flight testing its first generation air-to-ground bidirectional link capable of 20 Gbps in each direction. The aerial payload is mounted on a Cessna aircraft and is being flown at altitudes up to 20,000 ft.
They point out however that the next generation air-to-ground communication system will be capable of supporting 40 Gbps each on uplink and downlink between an aircraft and a ground station, and this is scheduled to be flight-tested in early 2017.
“We will continue to push the limits of wireless capacity over long ranges while staying within the tough size, weight and power constraints of Aquila communication payloads,” they said.
Facebook is not the only tech firm looking to connect the developing world. Google has been steadily ramping up efforts on its Project Loon program, an initiative that sees giant balloons beam down Internet to regions without online access.
Google has been working on Project Loon since 2013. The project uses high-altitude balloons placed in the stratosphere at an altitude of 20 miles to create an aerial wireless network with up to 3G-like speed.
Sri Lanka announced it would be the first to use Google’s Project Loon to cover the country with Internet access.
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