Phew, we can all rest easily. Quadrature amplitude modulation means we can carry on uploading cat videos for the next decade.
University of Glasgow working with Chinese counterparts to speed up the web
In a 21st century dominated by digital communications, it seems rather counterintuitive to imagine that the internet we all enjoy could be considerably improved by old-fashioned analogue technology. But that is the nub of pioneering work being undertaken by communications technologists at the University of Glasgow, in conjunction with their academic colleagues in China.
Already demonstrated in theory, the work is now at an advanced experimental stage, and looks likely to be adopted in three to 10 years’ time by all the major telecoms companies who have a hand in managing what is known as the ‘core network’ of the worldwide web, the main feeder pipes that keep traffic along the information superhighway happily moving along.
Physically, the core network sits two steps beyond us at home; we, as broadband consumers, are situated on what is known as the ‘access network’; our data then travels to the familiar green roadside cabinets and beyond to the telephone exchanges of the ‘metropolitan area network’, and then finally to the core, the giant data tentacles that propel the likes of Google, Facebook and YouTube data from users in the UK to the rest of the world.
When I talk to Dr Duncan Brem- ner, Business Development Manager and a Senior University Teacher within the School of Engineering, he describes the core network in the UK, which travels between key cities such as Glasgow, Edinburgh, Newcastle, York, Cambridge/Peterborough, London (down one side of the country), and then up the other side passing Birmingham, Manchester and Carlisle. So a bit like a ring main, I ask?
“Yes, it is a bit like a ring main,” says Bremner, who I catch up with just a couple of days after he’s touched down from Chengdu in China. He’s still catching up from the jet lag. The prelude to our conversation lies in an announcement made by the University over the summer that it had signed a partnership agreement with one of the most important state-owned enterprise companies in China to develop an international optoelectronics industry base in the Lingang area of Shanghai. Optoelectronics is the study and application of electronic devices that source, detect and control light, and has the potential to transform communications, looking to a world beyond 0s and 1s technology, making fibre broadband ever faster and more efficient.
And it can work not by digging up the existing fibre optic network in the ground and tinkering with it; instead a combination of software and hard electronics will work at the end points of a piece of fibre – the transmitters and receivers, to boost the amount of data that can be carried along the core network.
Whilst the work being delivered at the moment by the likes of BT Open-Reach and Virgin Media to install more and more fibre in the ground will go on unabated, the technology Dr Bremner describes should futureproof the industry for the next generation, allowing the core to go from speeds of 10gbps currently, to around 5-600gbps.
“If we keep on passing many more pictures, videos of cats jumping into fridges, or whatever else, on to YouTube and Facebook, that in turn places much more demand on the core network,” says Dr Bremner. “So by increasing the capacity of the core network, by deploying this technology, it will be of notable benefit. If they deploy this new technology, it broadens those pipes out without requiring any more fibre – effectively it should alleviate the bottlenecks we are now seeing.
If you’re talking about streaming high definition television at 20mbps, you’ve got kids surfing the internet and your wife’s listening to music, whilst you’re looking at HD videos, it’s starting to get to that pain point. You notice that especially at peak periods in the evening, around 5 or 6pm.”
And it’s using theories that have been in existence since the invention of the wireless, says Dr Bremner. The techniques have long been used in radio and but can be applied in a digital setting. Currently, fibre optic communication relies on sequences of digital 1s and 0s (switching off and on) to transmit data using laser lights. Instead of there just being those two states, the new technology will introduce fractions like 1/3, and 2/3 to increase to four states, doubling the amount of data that can be transmitted. That can be further increased to 16 by splitting into four (in phase), and four (in magnitude).
“We can go up to higher orders than that,” says Dr Bremner. We can even go up to 64 QAM [Quadrature amplitude modulation], which gives you even more states, 64 different states for every symbol. You’re still running at a symbol rate of 10gbps. Instead of going just off and on, you’re sending 64 different options to it, which means you hugely increase the capacity of the fibre, but still using the same fibre.”
My head is a little befuddled by this time, but thankfully Dr Bremner says it’s a bit like having 64 lanes on a motorway, as opposed to just two, which helps alleviate my own bottleneck, and also the real one which is being squeezed every year by the annual growth in internet traffic or around 20%.
“I think that’s the most important thing. People transmitting photos on Facebook don’t really care about the finer points of whether it’s 1s or 0s or if it’s 16 QAM, they just want the photographs to get to their friends,” says Dr Bremner.
“And as we become more and more digitised and more and more dependent on the internet, not just for information but as raw communications this will be essential. It’s driving the technology forward to meet the market demand. It’s not just technology because we can, as some of the ideas are actually old, but the impor- tant thing is making sure we’re future proofing the fibre network that is being laid down today for probably the next generation or so.”
The agreement has led to the establishment of the Shanghai Lingang International Photonic Integrated Circuit Joint Laboratory (PIC Lab) which will foster collaboration between the University of Glasgow and its partners in Lingang. PIC Lab aims to accelerate the development and commercialisation of optoelectronic integrated chip technology, integrating multiple optical components on a single chip and packaging the chips with high-speed electronics, to address the demand for high speed network connections for the next generation of the Internet.