Peter Cochrane: We need to forge a radical path to 6G

5G is way too inefficient for the IoT, argues Peter Cochrane

With the 5G rollout underway, creative minds are already turned to a future 6G.

5G thinking is largely dominated by human needs and machine connectivity remains second in the queue. But the IoT population is growing fast and forecasted at more than 50 billion ‘things' by 2030, when it will be compounded by the emergence of SMARTS (Software Manipulation of ARTefacts and Systems).

Extensive investment in optical fibre to ever more new and socially unpopular cell sites is required for 5G. However, this could be overcome with home and office microcells on Gbit/s FTTX providing infill coverage. This might see 6G breaking away from the cell tower model by adopting opportunistically connecting via large-scale mesh nets ideal for machine dominated operations.

Without doubt, 5G is by far the most energy hungry and wasteful mobile technology to date, and perhaps more than the planet can afford. Some cell installations consume over 10 kW, and the possibility of billions of nodes for M2M and the IoT is clearly untenable! 6G has to address this whilst satisfying a far greater service demand at around 10 per cent of the 5G budget.

The VHF and UHF wireless spectrum crisis is a manifestation of a management failure engendered by the artificial constraints of a failed ‘bands and channels' model. In reality, broadcast bands operate at less than 20 per cent occupancy, whilst the spectrum spanning 3-to-300 GHz is less than 1 per cent. This is a big 6G opportunity for a dense machine dominated world demanding new very low power modes.

At frequencies greater than 100 GHz, high gain on-chip antennae with beam steering are possible and vital to transmitter power reduction. This progressively improves as we migrate up the spectrum by virtue of improving receiver sensitivity and huge antenna gains. SMART materials and surfaces also promise high efficiency absorption, scatter, and steered reflection to provide a 6G signal reinforcing environment indoors and out.

The wireless community is almost entirely imbibed with the notion that bandwidth is expensive and should conserved, and that just leads to more and more signal processing. But it doesn't have to be this way! Bands and channels are a manifestation of the analogue era and now pose unnecessary limitations on dense short range digital communications.

In reality our wireless systems mostly remain analogue with digital modems at each end, and we ought to go fully digital. UWB or HWB (Hyper WideBand) could see the abandonment of wasteful bits/Hz optimisation, an abandonment of band and channel controls and constraints leading to a Hz/bit bonanza. This would be ideal for the IoT and SMARTS, but it may be a bridge too far, and we might have to wait for 7/8G for adoption by a new breed of engineers.

A domination of WiFi hotspots currently exceeds mobile cell sites by more than 380 million, plus offices and homes with over two billion microcells on the end of broadband suggests that this balance is unlikely to change. And then there are Bluetooth, ZigBee and a host of new standards being developed, so it cannot be assumed that the ‘G' technologies will dominate. However, a smart 6G could exploit these open connections when they are available.

How exactly 6G development will pan out is impossible to say, but logically, a time will also come for a radical condensation of the numbers of wireless systems on the basis of the economies of scale and our efforts to realise sustainable societies. Surprisingly, developments in materials science, SMARTS might lead the way and force some convergence.

Peter Cochrane OBE is professor of sentient systems at the University of Suffolk, UK