With 76 per cent of adults now owning smartphones (according to research by Statista) and ever-increasing demands for more data, at higher speeds, we are fast approaching what communications specialists have termed a ‘spectrum crunch’: namely, when the predominantly radio frequency channels that carry packets of information to our devices become so crowded that there is nowhere left to go.
In this apocalyptic vision of the future (imagine life without House of Cards), the services we all rely are potentially starved of the bandwidth oxygen they need to run quickly and smoothly, whether that’s for domestic or business consumers who are spending more and more time attached to Android or IOS devices.
With the future set to be dominated by wireless – backed by ‘core optical broadband’ – we ask John Thompson, Professor of Signal Processing and Communications at Edinburgh University, which communications technologies will win out.
Wi-Fi versus wired
‘If you look at fixed internet connections, growth is now quite slow,’ says Professor Thompson.
‘A lot of growth is likely to be in mobile networks for the foreseeable future. It’s also quite diverse according to region of the world. In Asia the growth is higher, whereas in Europe it is significantly lower because Europe has much more infrastructure and operators. The drivers are different in different parts of the world, in terms of what people want to do. Work is ongoing to define new wireless standards and I expect in the next five years the mobile industry will define 5G systems.’
‘In Europe I guess it’s true to say that companies would like to provide more capacity but I think the mobile operators are operating in more strict financial situations because they are now in more mature markets. They are looking for technologies that will allow them to open up new markets – especially to support so-called machine-to-machine or Internet of Things communications.
According to Cisco mobile offload exceeded cellular traffic for the first time in 2015, with 51 per cent of total mobile data traffic offloaded onto the fixed network through Wi-Fi or femtocell.
‘A lot of internet traffic is now carried through Wi-Fi connections,’ says Professor Thompson. “It’s better for operators as they can use resources more effectively for people who don’t have Wi-Fi.
‘In terms of mobile data for the foreseeable future because there is so much penetration of Wi-Fi, 3G and 4G, and also in Europe lots of operators have significant financial constraints, they won’t invest unless there is a compelling case i.e a they get a return.’
‘I think at the moment wireless mobile technologies standards won’t be defined until 2018 or 2020 at least,’ says Professor Thompson. ‘It may take 10 years to develop and rollout new technologies and if 5G is successful it may be 2025 until those technologies are fully deployed.’
‘With new technologies such as Li-Fi I think it probably will take some time and it may need to identify a unique selling point,’ says Professor Thompson. ‘So with Li-Fi you can make the argument that it might be useful in hospitals, if you have have a concern about radio technologies in some medical environments.’
‘It’s also a very secure technology because you can stop light going outside a building, and constrain it within a room. Right now with Li-Fi, people are looking at it for position location. If you are wandering around a supermarket, for example, where do I find the bread? It can potentially locate where you are and provide information about which aisle to find the bread. Many phones have GPS, which allow you to figure out where you are outdoors, but indoors is not as yet a solved problem.’
‘With Li-Fi we have the advantage that everyone has lighting in their home and in their offices so there’s certainly a compelling case that if you can find an effective opportunity to use it then it doesn’t take that long to move from a position where most peoples’ lights aren’t used for communication to a position where they are,’ adds Professor Thompson.
‘At the moment most cellular communications systems operate in a particular frequency range, from about maybe 6-700MHZ to about 2.5GGHZ, which is the microwave frequency band,’ says Professor Thompson.
‘In terms of radio technology something that may come in in the next 5-10 years is the use of higher frequencies, so there are frequency bands between about 10GHZ and 100GHZ or even higher which are typically called the millimetre wave spectrum,’ says Professor Thompson.
‘Up until now these frequencies have not been used because the signals don’t propagate as far and it wouldn’t be realistic to build out a complete cellular network for the whole of the UK. But on the other hand if you’re in central Edinburgh, Glasgow or London, in a similar way to Wi-Fi access points it might be cost-effective to put in millimetre wave frequency technology. Maybe in 10 years’ time your phone or laptop will have a millimetre wave technology capability. And the advantage of operating at these higher frequencies is that the bandwidths are much higher so you can achieve much higher data rates, so video streaming becomes easier.’
‘With millimetre wave I don’t think it will replace existing systems but it is another technology and could be particularly useful in urban areas or where you have lots of people around.’
‘If you look at the frequencies currently used for transmitting TV signals there are gaps in the spectrum and that is where white space spectrum exists,’ says Professor Thompson.
‘There have white space spectrum trials in the US – there was a town where they used white space Wi-Fi – but I don’t get the impression it has taken off hugely.
‘And like Wi-Fi, white space is a licence-exempt spectrum, so anyone can use it. Obviously the limitation of that is that you’ve got no protection. If you’re trying to build a commercial service on that, the danger is someone else comes in and uses that spectrum as well, and causes you interference, and maybe makes it more difficult for you to operate your system.’
Internet of Things (IoT) communications
‘Cellular networks want to use their networks to power machine-to-machine communications,’ says Professor Thompson.
‘I think there will be competition with some companies proposing proprietary or private technologies, and cellular networks and white space want to get a share of the action using existing systems. It remains to be seen who will win out.’
‘Prices of devices will be extremely low (for IoT) – and that maybe makes it a more constrained market. With mobile phones people are willing to spend maybe £2-400 on their next device but if I’m buying a communications device to put at the centre of my house or attach to my fridge it’s going to need to cost between $2-5. Every time I go to a conference there’s always huge predictions of how many machine-to-machine devices there will be out there in the next five to 10 years. But the issue is that the cost of these devices will be lower and that may influence who is the winner in this particular case.’
‘We will always need the core optical network,’ says Professor Thompson ‘If you look at energy efficiency, and communicating data over a large distance, it is orders of magnitude more efficient to do that over an optical fibre, so I don’t envisage to be honest that we would ever reach a situation where everything is done wirelessly.’
‘Just as we have seen a growth in the capacity of wireless networks there has also been a growth in terms of the wired optical technologies: there is a bit of an arms race going on. It is constantly evolving, and people are finding new ways to try and increase capacity, but in practice we need both systems. Wireless technologies will be in the main the ‘last hop’ to the user; we like to work wirelessly but I think we will always require that optical backbone to connect us all together.’