This article first appeared as an interview in the February edition of Global Military Communications, page 12, edited by Laurence Russell. Read it here.
Blu Wireless specialises in millimetre wave (mmWave) and advanced wireless technology for defence, transport, and private networks. Our work on new mmWave potential has the potential to deliver unique capability to avoid interception and jamming, as well as high data rates. Our Chief Commercial Officer and Co-Founder, Mark Barrett, recently sat down with Global Military Communications to discuss mmWave technology in detail and its applicability for defence communications.
Assessing the digitisation boom during the pandemic
We’ve seen a massive shift from face-to-face meetings toward online correspondence via teleconference. This has been quite relevant to us, as Blu Wireless has been keeping a close eye on the increasing rate of video transmission over IP networks, which has been a strong driver in the change of data rate.
This in turn has motivated a certain cultural shift. People have become increasingly used to digitised tools as they’ve become the only option available. I think as normality resumes, the habits we’ve learned over the pandemic will remain, given that so many of us have been forced to embrace remote and connected solutions, and recognised the efficiencies therein.
In my own experience that has increased customer awareness of poor (mobile and fixed) network coverage. This also includes, poor connectivity on the train, which – even with a good connection – is often not suitable for video conferencing applications such as Zoom or Teams due to long connection latencies. This experience is also reflected in rail passenger satisfaction surveys. Interestingly, Blu Wireless is also involved in improving UK passenger rail Wi-Fi as part of the ‘Rail 5G’ initiative from First Group by providing gigabit grade connectivity to each passenger train.
Overcoming range, mobility and interference management challenges in mmWave systems
Our company is comprised of a powerful combination of experts in radio engineering, silicon engineering, real-time software engineering, and digital signal processing. We’ve brought all of these deep technology skills together to solve these issues.
Traditionally, mmWave communications have been categorised as being quite short-range, in the order of 10s of metres. What we’ve done is maximise the radio link budget, the transmitted power, and the receiver sensitivity to increase the range to several kms, all within the allowable regulatory transmit power limits in Europe, the UK, the US, and Japan.
We have also extended many of the features in the IEEE 802.11ad standard to do that and added a few new ones; one of them is sub channelization, where rather than use the full 1.8GHz, we can divide down into smaller steps to enable longer range at proportional lower data rates. For example, in one defence application we can extended the range to four kilometres through use of these methods.
In terms of mobility, we’ve use real time digital signal processing (DSP) based methods for Doppler shift compensation, a phenomenon which particularly affects high-frequency wireless waveforms. We’ve also implemented sophisticated handover protocols customised to use with mmWave connectivity. This enables seamless make-before-break connectivity, as one would experience on traditional mobile networks. We believe that this capability is unique to Blu Wireless.
Finally, we have added further wireless DSP methods to minimize the impact of co-channel interference. All in all, we ensure the technology delivers the cutting-edge performance that our partners are looking for.
How to use of 5G gigabit networks via mmWave – standout business cases
With respect to Blu Wireless, we’re aware of quite a few. We particular focus on infrastructure requirements, particularly backhaul from 4G/5GNR mobile phone base stations, for example using Open-RAN interface technology. An important sector for us right now is transportation with the aforementioned wireless connectivity we’re introducing to the UK rail network.
We’re also involved in a number of defence applications. We are seeing a lot of activity and interest from the US, France, and the UK in terms of mmWave communications across all domains. Covert communications, mesh networking, positioning and security are all relevant areas. Part of that is in the interest of connectivity solutions that don’t need to rely on fibre optic. Mission-critical users always appreciate alternate methods to improve network resilience to support mission delivery.
Is mmWave the future? How it compares to other emergent transmission methods such as those used by optical satellites
In space, optical transmission is very effective because it’s an environment devoid of water vapour, weather, and other gases. Back on Earth, the situation is rather more complicated – you’ve got rain, fog, and interference from all manner of sources all of which severely impact the performance of free space optical communications.
Electro-optical devices suffer quite badly from attenuation in the presence of water vapour, so whatever optical transmission can boast, those efficiencies don’t amount to much here on the blue planet. mmWave is also impacted (to a less extent than optical) by rain fade of course, but typically that can be predicted and accommodated within the system design.
mmWave addresses some very pertinent and real problems wireless technology has long struggled with, particularly in the defence space. One example is interception by near-peer adversary electronic support measures (ESM) systems. There are public domain records of such attacks being employed by the Russians, namely upon Ukrainian tank battalions in 2014 using ESM signal interception. Electronic warfare ESM capability of ‘near peer adversaries’ will therefore increasingly become a serious concern for the world’s defence organisations across all domains. The use of mmWave for such communications offers can’t be tampered with as easily as traditional telecommunications.
Another problem mmWave solves is deployment in GPS degraded environments. GPS is notoriously easy to jam, which has led to a working assumption that GPS will likely be denied in any hypothetical near-peer conflict. MmWave systems can be used to create a relative positioning network where everybody is connected in the mesh, allowing positioning without GPS, which is a crucial asset.
The safety of mmWave
We have a 5G project in the City of Liverpool which is part-funded through the UK Government’s DCMS 5G Create programme. This ‘L5GC’ project involves installing street-level Wi-Fi using our mmWave nodes to provide high data rate backhaul to the core internet. Those installations were there to improve Internet connectivity for health and social care services and have more than proved their value – particularly in delivering remote tele-health services during the Covid-19 pandemic.
One of the concerns raised by the local population in Liverpool was that of Radiation Health caused by new 5G transmissions. The L5GC programme raised the issue with the UK media regulator Ofcom through their MP. Ofcom subsequently conducted live radiation exposure tests on the Blu Wireless mmWave equipment in use in Liverpool. Our equipment already meets the requirements of the International Commission on Non-Ionising Radiation Protection (ICNIRP), which specify the Radiation safe distance of 30cm as the point where the power density drops below one milliwatt per square centimetre.
In fact, the maximum level that OFCOM could detect with their onsite equipment was only 1% of the ICNIRP limit – at a distance of several metres from the Blu Wireless mmWave equipment. So people travelling on a bus passing a street-level access point will be exposed to a peak level of less than 1 percent of the total safe limit determined by international regulators, or a hundred times below the ICNIRP radiation health limit. Ofcom has subsequently published their full test report.
Next generation mmWave technology
We’re expanding the range of the wireless mmWave spectrum that we’re able to address, occupy, utilise, and deliver to customers. At the moment, the majority of our work is focussed on the 57-71GHz spectrum, which is a licence free band in the UK, US, Europe, Japan, and elsewhere.
As I’ve touched upon, we also have projects at higher-frequencies which use more advanced mmWave phased array antenna radio front ends up to 100GHz.
We’re also working on the next generation of our silicon technology, which we predict will increase the data rate deliverable by those devices by a further factor of 10, up to 30Gbps. That leap forward combined with the potential for multiple links pushes the envelope for throughput capability into unforeseen territory, for which very high-end applications will be possible.
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