5G – A Revolution in 5 instalments

5G – A Revolution in 5 instalments

(First published in 2015)

5G started its life on the simple premise that a generation of mobile technology must exist beyond 4G and it was never too early to begin research on what this might be. Two disparate themes got painted onto the canvass by their advocates very early – the exploitation of mmWave spectrum bands and the Internet of Things – not natural bed-fellows.  It would have been helpful to have had time for research to have progressed and space for thoughtful debate on what the world most needs from 5G and on what timescale. But instead industrial and political ambition has been driving 5G towards early implementation by 2020. There is a risk that 5G will mis-fire but we have not reached that point yet.

What is evident from the debate so far is that 5G will not be a single radio access technology that sweeps away all the earlier generations of mobile technology. It looks more like revolutionary ideas that will be implemented in an evolutionary way building out from what exists (LTE, WiFi, GSM etc) – probably in 5 installments and we urgently need a global consensus on the script and road map around this more plausible reality.

The installment of the 5G revolution that currently has the most momentum behind it is the use of mmWave spectrum bands to provide huge data rates and ultra-low latency. It is an exciting technology development. What gives it particular momentum is that spectrum managers appear confident in making global spectrum allocations available for such a 5G technology. Spectrum availability is a powerful market driver. However it is likely to take much longer than 2020 to commercialise to a mass market. It also has one other draw-back: the economics of coverage will limit this to a dense-urban story.  A 5G mmWave story will be important in the long term but it is not a credible 5G revolution on its own due to its likely coverage limitations.

Another installment of the 5G revolution could be the exploitation of spectrum between 2 and 4GHz for very high density small cell deployments providing contiguous coverage. It is another dense urban story but differs from the mmWave story in targeting “mobility” rather than “nomadic” connectivity and being easier to commercialise on a 2020 time-scale. But the road block to this development is the inability of the spectrum managers to sort out a harmonised band that could be available on a 2020 time-scale (at least across the EU). Another commercial barrier to be tackled is the base station site rental model that could sink the economics of deploying millions of cells across public spaces but this is soluble by public authorities that own many suitable structures.

The installment of a 5G revolution that could offer the fastest new application benefits is the one currently receiving the least attention and that is a new 5G technology deployed on UHF spectrum that delivers national coverage. Many of the most promising vertical applications (eg transport) require very reliable pervasive national coverage. The conventional wisdom is that there is nothing better in the technology locker for use at UHF than the current LTE 4G technology. This may or may not be true. But there still could be revolutions to be made in a 5G world in the ways 4G technology is exploited to provide a leap in reach, reliability and rural coverage.

A fourth installment of a 5G revolution is the exploiting advanced spectrum sharing. The geographic efficiency of use of spectrum above 2 GHz is shockingly low. Even in dense urban areas there are efficiency gains by a far more intelligently mapping local spectrum resource to instantaneous demand. The barrier here is political. The large multi-national companies that bought spectrum expensively are not obliged to share it and are unlikely to ever want to do so all the while regulators see spectrum sharing as a means to shoe-horn in new entrant competitors. This is another road block that may take a while to clear.

The final installment of 5G revolution (and probably the most potentially transformational) is a total end-to-end re-engineering of the entire wireless broadband Internet to deliver to users “always sufficient” resources to meet their instantaneous demands. The challenges here are enormous, not least the modernisation the Internet TCP/IP protocols. The main barrier here is the way the main global standards bodies of 3G PP, the IEEE and the IETF each sit within their own industry silos.  How to get them together to work to common goals is by no means clear. A recent initiative by BSI and ETSI on infocom protocols for a post 2020 world offers a seed of hope but a very fragile one.

The well-judged management of expectations is an important tool in making successful mobile revolutions. The mobile world is rapidly painting itself into a corner that 5G is about 10 GB/s data speeds using mmWave technology, massive MiMo and beam steering. To self-limit 5G to a dense urban nomadic story and based on a technology that may not be ready for mass global commercialisation by 2020 is a tactical mistake. We need to re-write the 5G script as a revolution in evolutionary installments. The most pressing task for the 5G “thought leaders” is how best to remove the road-blocks in the way of the other installments. What could be delivered by 2020 that would make a real impact on a wireless based expanding digital economy?

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