News: Ericsson’s David Hammarwall explains the challenges and opportunities of the next generation mobile network.
The roll-out of 4G has been fairly successful, but within a few years it will reach its limits as a technology as connectivity demands change.
From the operator side, there is still the need to battle over spectrum every time an auction comes up. O2, for example, faced a considerable handicap when it missed out during the auction of 2013.
There are also in-built inefficiencies in the technology, as Ericsson’s David Hammarwall, Strategic Product Manager of Radio, tells CBR:
"One of the deficiencies of 4G today is that it is always broadcasting signals. That limits the kind of energy saving you can do and also reduces performance because there is a lot of interference that this broadcast is creating even if the cells are almost empty."
So while 5G is still a way off and has not even been standardised yet, it is possible to get some idea of what it will look like just by looking at the flaws in 4G which it will aim to solve.
"The energy efficiency is a key aspect of 5G. One aspect is what we call lean design, which means that you only transmit signals in conjunction with a data broadcast. The key advantage is that when there’s no traffic on a node it is essentially turned off without power consumption.
"These lean designs will not only improve performance but also enable energy efficient solutions.
"Of course, in 5G we can take this to the next level, where we have a fully standardised solution and have the opportunity to reduce the power consumption and address energy efficiency along with improving the performance."
Another problem that 5G will aim to solve is the spectrum crunch mentioned above. 4G currently operates within a fairly small range of frequencies.
"Today’s cellular networks are starting to have deployment in 3.5 GHz," Hammarwall says. "But still we are using a total of maybe 3 GHz of spectrum. Ranging up to 20 or 30 you will have more total spectrum available."
5G will be designed to operate in much higher bands, opening up a whole new range of frequencies.
"We will have much more spectrum available: we will break the current requirements for low frequency bands. We will see much higher frequency, enabling much more spectrum to make it more acceptable to traffic a lot of data.
"Another key trend will be using unlicensed spectrum. This will allow cellular operators to deliver data at very low-cost, using the same unlicensed bands which other forms of wireless have used for many years now.
"We see 5G really being built out of two key elements: the evolution of LTE and a new radio access. LTE evolution is already taking off, and we see many precursors to 5G already being enabled."
Although 4G provides faster connectivity than most consumers are used to, 5G will of course aim to boost this as well.
"We will also see improved consumer experience. We will have improved peak rates and low latency applications which will be important for high-end use-cases. We also see video being a key growth factor on the internet. We believe that by 2021, where we see broader adoption of 5G, more than 70 percent of the content will be video-driven."
Another area where 5G can learn from 4G is in the setting of standards.
"The main thing here is to look at the track record," says Hammarwall. "If you go back you used to have a huge split in standards: there was 3GPP2 versus 3GPP.
"What we’ve really seen already for 4G is the entire world uniting behind a single standardisation track, and really giving the mandate to 3GP to proceed. The key learning from that is to drive the industry in the same direction for 5G.
"We are very confident that we have established standardisation bodies, and with historic learnings we will be able to maintain this for 5G as well. It is for the greater good of the industry that everyone is driving to this common goal."
No technology is perfect, however. Basic physics means that boosting the frequency of radio signal lowers its wave-length.
"When you go up to the higher frequency bands you reduce the range. There is a number of technologies being pursued to counter-act that. First of all, there will be quite a lot of antenna: we use MIMO technology to boost the coverage.
"You can do that by beam-forming the energy to the specific user to extend the range. That along with multi-user (MU) MIMO will provide a lot of capacity."
5G will also be reliant on small cell technology, including femtocells and picocells, which have so far not seen huge adoption.
"The other aspect is to have 5G allow for much denser deployment. Small cells have been a key scene for some time but have not taken off yet. With 5G around the corner, small cells utilising this higher spectrum will be a key point. This can be split between indoor and outdoor solutions."
Ericsson is working with property developers to build small cells into Greenfield sites, including Skanska, known for building the Gherkin building in London. In Los Angeles, Ericsson is building LTE into street-lights.
In LA, Ericsson is partnering with Phillips and the City itself to roll out the network. With Skanska, it is a three-way partnership between Ericsson, the operator and the developer.
These kind of partnerships provide examples of the new business models that might emerge during the small cell roll-out.
"We are seeing small cells deployments focused on both consumers and business users," Hammarwall says. "Generally speaking, outdoors and in public venues, small cells will support both, but, for business users in office buildings, there can be more business-critical applications, which may require a higher density of small cells.
"Of course, high traffic venues, such as stadiums, will also require a more dense deployment of small cells."
Once the small cell roll-out is completed, the aim is that it won’t be needed again.
"We work with future compatibility, so of course we will add software improvements to provide compatibility with future standards. For instance, the dock system is a highly scalable solution where we connect it to our cellular macro network hardware. That will be fully future-proof, where we will have feature parity with our large-scale cellular outdoor networks."
Dave Fraser, CEO of Devicescape adds that while 5G will create "significant improvements in operators’ capabilities", it will be important that existing infrastructure is not ignored.
"Wi-f already provides the superior connectivity experience inside millions of buildings and will remain fundamental to the smartphone user. In public spaces, free amenity wi-fi of the kind offered by numerous consumer-facing businesses and premises owners has become a rich, dense connectivity resource.
"It already exists on a scale that is simply too expensive and impractical to replicate with further cellular infrastructure deployment, but can be easily integrated into a wider, operator-delivered connectivity service. Only by blending all forms of available connectivity can operators give smartphone users the consistency of experience they require."
It is encouraging to think that it won’t be long before most current connectivity problems are solved.