Beam-steering the way to real-world mmWave 5G

Telecoms.com periodically invites expert third parties to share their views on the industry’s most pressing issues. In this piece Esat Sibay, COO and CFO at ALCAN Systems looks at how to get the most out of millimetre-wave 5G.

The past 12 months have seen the much-anticipated arrival of 5G but, so far, it’s not quite living up to the associated hype. If we take for example the US market, which is making some of the biggest strides in this field, operators have been firmly focused in low band frequencies. While there is still a great deal of value in this iteration of 5G, even T-Mobile has conceded, low band 5G will only be 20% faster than existing 4G LTE networks. Undoubtedly this is a move forward for the industry but, it is not a network technology that is going to see all the promises of 5G, and the ‘fourth industrial revolution’ that now seems synonymous with it, come to fruition. The truth is, to get even close to realising the potential of 5G, operators must enter the unchartered waters of mmWave 5G.

Why mmWave?

mmWave frequencies have long been associated with 5G delivery, but they are not without drawbacks. There are two big problems we encounter when using mmWave frequencies for 5G; poor penetration – a wall, or even a user’s hand can block signal, and a limited range of only 1000ft; that’s 2% of the range of 4G. So, when it comes to designing a commercially viable 5G network that can deal with these restrictions in a real-world environment, mmWave 5G poses a significant challenge for operators.

With such huge issues to navigate, which fuel uncertainty around its suitability, the question is, why bother with mmWave for 5G? The answer is simple, the 20% improvement on 4G that is possible in the low bands isn’t enough. It is unable to support dozens of proposed 5G use cases and puts a ceiling on the return operators will see on 5G investments. However, overcome the problems associated with mmWave and you are left with a technology capable of delivering above and beyond the promises of 5G. Take Telstra, only this week it has announced mmWave 5G trials that could achieve speeds up to 8 times faster than 4G. High-bandwidth, super-speeds, high availability and a significant improvement on 4G make mmWave frequencies ideal. This is of course is why the industry is so keen to tap into their potential– but how?

The boons of beam-steering

One of the key technologies that allow 5G to reach its potential by overcoming the restrictions of mmWave is beam-steering. As the name suggests, it allows a signal to be focused in a particular direction, rather than radiating 120º as it normally would. The signal, which is controlled with Electronically Steerable Antennas (ESAs) enables precise propagation and a faster and more reliable connection than would otherwise be possible. It minimises penetration losses and increases the reach of 5G working in mmWave frequencies.

In principle this sounds like the perfect answer; simply steering around obstacles to enable 5G, but inevitably there is a catch. The catch is that ESAs that so effectively tackle the challenges of mmWave penetration, are typically too high cost to be a realistic option for most operators. Based on existing ESA technology, operators are looking at tens of thousands of dollars per antenna. This may be palatable if only a few per city were required, but given the shorter reach of mmWave frequencies, even when enhanced by beam-steering, it is a technology that must be deployed in high volumes to be effective. Manipulating radiation patterns to navigate the physical limitations of mmWave frequencies is crucial, but operators need to be able to recoup the costs of equipment. So, the next task they face is finding technology to deliver beam-steering at the scale they need and with costings that allow them to have a commercially viable 5G network.

The answer: you could be looking at it

There are many different ways of approaching this. Looking at military solutions for beam-steering, using repeater antennas to expand coverage, but one approach uses technology you are very literally staring at.

Liquid Crystal, the material that is used in most screens across the globe, can be used as a way of developing ultra-low-cost, energy efficient and low-profile beam-steering antennas that offer a potential cure to many of the headaches associated with mmWave 5G.

First explored as part of a research project at Darmstadt University, Liquid Crystal Antennas take what is now an everyday material and evolve its applications. This results in antennas that allow operators to manipulate radiation patterns like any other beam-steering antenna, but the materials used mean the resulting ESA can be built 10 times cheaper than traditional options. Not only this but by using Liquid Crystal to enable beam-steering, the antenna functions with low-power and can be built with a form factor to minimise visibility – think how thin a typical mobile device can be made and this puts it into perspective.

Most technologies that are being developed are being stretched to their physical limitations to work in mmWave frequencies, however a quirk of using Liquid Crystal as the core material for ESAs is performance improves in higher frequencies. This makes it not only a viable solution to 5G stumbling blocks, but it has the potential to thrive in a 6G world.

Conclusion

There is no two ways about it using mmWave frequencies is the only way operators can build a 5G network that lives up to the promises and hype we have seen over the past few years. That said, delivering in these frequencies is a significant challenge which requires operators to completely rethink the architecture of their Radio Access Networks. It needs equipment that does it all – improved RF performance, with a smaller physical footprint, and lower power consumption, all with a reduced cost of ownership.

Operators across the globe have acknowledged that mmWave frequencies must be a key aspect of 5G networks. However, a big question mark still hangs over the best way to achieve this. Regardless of which technologies operators look to, to ensure 5G is a success, it is critical that in striving to achieve mmWave 5G they do not fall into an investment pit of spiralling infrastructure costs that cannot be recouped.

Esat Sibay is CFO and COO at ALCAN Systems, a specialist in the development of smart antennas.  He is responsible for financial management, business development, legal and administration at ALCAN and has more than 20 years of experience in finance and strategic consulting with companies such as HSBC, Citigroup and Accenture. He also holds an M.Sc. in Finance from London Business School, a Diploma in Economics from the London School of Economics and a B.Sc. in Industrial Engineering from Bosphorous University.