Is the real 5G more muscle, longer arms, smarter brains or just a glamorous face?
5G began as a largely unstructured dialogue in the research community. This allowed a free flow of ideas but also led to a very expansive all-embracing vision emerging that has excited the interest of governments around the world but unchallenged by the realities of the world it has to find its place in. The next phase of 5G will whittle down 5G to the elements of the vision that have the most industrial support (this has already started in the standards body) and soon the market will whittle down further “the real 5G”. How will this “real 5G” add to the mobile broadband infrastructure we already have? Will it be more muscle, longer arms, smarter brains or just a glamorous face? Can we have it all in one big revolutionary bang in 2020?
The glamorous face of a change of mobile technologies generation is the exciting new services and applications it enables. The three most mentioned in a 5G context are:
- Internet of Things
- Applications within vertical industries to modernise those industries
- 4K video and virtual reality – both massively data hungry
Each of these requires better networks in different ways:
The first is about how networks deal with massive concurrent connectivity. The Internet of Things is not waiting for 5G networks to arrive but they will become essential to lift the ceiling to allow massive numbers to emerge in the future.
The second demands very pervasive coverage and poses “a chicken and egg” problem. There has to be pervasive coverage before a number of industries will rely on upon wireless solutions for their modernisation.
Finally any really enhanced video will require a more muscular wireless infrastructure able to do considerably more very heavy lifting of data across wireless networks.
“More muscle” has been central to 5G network research effort. The research output can be delivered in two quite distinct flavours of enhanced mobile broadband networks that poses rather different challenges – an easy one and very difficult one. The easier approach offers data speeds of 10 Gb/s (or more) with very low latency. But the coverage is limited to “hot spots” that might only number in the 10’s of thousands across the country with very large gaps in between. This makes it a nomadic rather than mobile service…an augmentation of today’s WiFi but with a more certain quality of experience. Places like football stadiums and other spots where large numbers of people come together in relatively small spaces will notice the difference with the arrival of this version of 5G enhanced mobile broadband.
The more difficult approach aims to only offer a more modest 1-2 Gb/s but spread it pervasively over a wide urban area (and indoors). It is a true enhanced “mobile” service broadband service. Mobility is what consumers want, it demands contiguous coverage and is hard to achieve even over dense urban areas. There are serious barriers in the way of such a hugely powerful up-grading of urban mobile infrastructures:
- A lack of ready access to RF channels at least 100 MHz wide in spectrum below 5 GHz (ie the 3.4-3.8 GHz band)
- The current site rents are prohibative for the number of cell sites needed. An inversion of the site rental model is needed from the current relatively few sites with a high rent per site to very large number of sites with a low rent per site
- Broadband back-haul is a gating factor even with today’s less demanding 4G networks. Daisy-chaining microwave links will help but may require access to dark fibre at the fixed network entry points.
- Lack of a new dense small cell roaming model to aggregate the coverage of all the installed small cells however provided – public or private. Without this (or some alternative radical cost sharing approach) the goal of pervasive urban wide mobile coverage delivering Gb/s data speeds is economically unattainable.
- Lack of a conditional spectrum liberalisation model that would allow mass private use of 5G spectrum (where the scale economies bring equipment prices down for public use) but ensures harmful interference to public cells can be effectively controlled. There is a need for some sort of interference control brokers…that could be the MNO’s.
All of these impediments have solutions but not with the current regulatory and business models. Without the will to think differently and piece together a model that solves the above challenges – this area coverage backbone of a 5G mobile revolution is unlikely to happen.
Longer Arms – The reach of reliable mobile coverage has always been on the customer’s complaint list. As society becomes more dependent upon mobile connections so more reliable national coverage becomes essential. It is one of the things most neglected by the 5G research community who have largely focused on enhancing capacity at the expense of coverage. This leaves unaddressed one of the main weaknesses of 4G, namely its poor cell edge performance in busy periods. But there are other developments coming along that can help significantly. The most important is the valuable 700 MHz spectrum becoming available around 2020 for mobile services.
Smarter Brains – However much investment is made in the capacity of networks it will never be enough to meet every demand at every place at every time. There is still much to do in the research community to understand how networks can be far more attentive to user demands in these stretching situations and ensure smarter networks marshal “always sufficient” resources to meet those demands. This was an idea first proposed by the IET in its DAN initiative aimed to give users the perception of being connected to a network of infinite bandwidth. It was taken into the ambitious 5G vision but achieving it is likely to need a revolution in the inefficient TCP/IP protocols that currently prevail on the Internet. An ETSI Next Generation Protocol group has made a start but such a revolution remains a long way into the future.
Summary of “the real 5G” that is likely to emerge by 2020
“The real 5G” likely to emerge on the current trajectory by 2020 is a veneer of extremely high data speed hots spots, many essential confidence building “toe in the water” applications trials and a useful augmentation of the reach of national coverage from the release of 700 MHz spectrum. There is the potential for 5G to deliver a huge amount more. But this will only be unlocked by a change of trajectory where (and when) governments, regulators and industry come up with new regulatory and business operating models. There is also a very large amount of unfinished business for the research community around more Demand Attentive Networks, the technology advances around spectrum sharing, better energy efficiency and attention to the cell edge shortcomings of 4G. Sitting alongside all of this is the need for some fundamental communications engineering improvements that include pushing far more fibre optic cables towards the edge of networks, lifting the height of 700 MHz radio towers and interim solutions for mobile networks to mitigate the shortcomings of Internet protocols.
5G looks on track to begin by 2020 but we are not going to get the big 5G vision all in one revolutionary big bang. Expectations need to be set that there will only be a modest start along a very long 5G map.