Bad neighbours? A comparison of LPWA technology options

Screen Shot 2016-05-11 at 10.24.43While the carrier community is celebrating the steady arrival of 3GPP defined cellular IoT that will enable the use of existing GSM networks with minimal impact through upgrades, there remains significant interest in alternative solutions in the unlicensed space.

Some of this interest comes from service providers who lack access to licensed spectrum, but the majority is being driven by use cases where the long range, extended battery life, and very low cost of Low Power Wide Area (LPWA) wireless technologies is a fundamental necessity. What is emerging though is a fragmented area of largely proprietary solutions, making it difficult for users to decide on which option best suits their particular use case.

The key approaches to unlicensed M2M connectivity can be split in to two groups: UltraNarrowBand (UNB) technologies; and those that employ some form of spread spectrum modulation (SSM).

Growth forecasts for the M2M market underline the need for these LPWA systems to be able to co-exist in license exempt spectrum and that any LPWA solution should be able to support  many connected devices – and this requirement is only going to become more important over time as the number of devices increases.

Real Wireless recently carried out a study that compared the levels of interference between networks using these two different physical layer architectures. This required us to model a scenario in which a UNB and a SSM network had overlapping coverage areas and various other sources of interference, including non-LPWA users, in order to study the ability of both technologies to mitigate interference.

This insight gained was that UNB and spread spectrum modulation networks can only effectively co-exist in very low capacity deployments. Shared channel operation, either between a SSM and a UNB network, or two SSM networks, would result in mutual interference and uplink blocking of both networks, except in cases of very low simultaneous user numbers.

In other words, the reality is that a SSM LPWA network architecture should be considered a ‘bad neighbour’, and multiple unlicensed IoT networks can only effectively share access to spectrum when they all also share a UNB architecture. However, given the number of use cases for these technologies, they will undoubtedly coexist in one location. As a result, this study has significant implications for technology choices in this important growth market.

To find out more about our study and approach to modelling of unlicensed IoT solutions, download our new white paper today.

Calculating the future: UK spectrum usage and demand

Today saw the launch of the first in a series of reports on UK Spectrum Usage and Demand from the UK Spectrum Policy Forum, at an event in London.

UK Spectrum Usage and Demand considers the spectrum needs of different sectors, and the social and economic contributions which they are able to make based on their spectrum usage. It reflects the contradictory priorities different industries hold – including space, utilities, business radio, meteorology and mobile – with a view to fostering open discussion and mutual understanding, in order to deliver maximum benefit from the UK’s spectrum assets.

For the report, Real Wireless was commissioned to provide a snapshot of current spectrum usage for the report, as well as calculating the expected long-term future needs of the major users of spectrum in the UK.

Last year Real Wireless became a funding partner and Steering Board member for the fledgling Spectrum Policy Forum. I act as voluntary chair of the Forum’s Cluster 1, examining spectrum applications and demand.

The reason for this is simple. Spectrum is a scarce resource, one that needs proper management and support if the country is to enjoy the benefits – a recent estimate valued spectrum as contributing £52 Billion per year to the UK economy. The UK Spectrum Strategy published a year ago set a target to double this contribution by 2025. Therefore, an independent, industry-led government sounding board such as the UK Spectrum Policy Forum is crucial to making the most of this asset – and Real Wireless is proud to support this vital work.

In today’s report, we found that there are multiple industries with conflicting spectrum requirements and only careful forward planning and a high level of mutual understanding will avoid future clashes.

After all, these industries rightly consider their work as important, and Real Wireless has long been an advocate for enabling the use of wireless technologies in a way which bridges the gap between the wireless industry and business, personal and public sector usage of wireless.

What’s crucial therefore is to plan ahead and spot conflicts before they occur, taking all needs into account in future policy debates to maximise the social and economic benefits from spectrum in the long-term.

A later edition of the report will include further sectors and lead the way to the specific work items which will allow progress on these areas – watch this space!

Today’s report from Real Wireless and the UK Spectrum Policy Forum, UK Spectrum Usage and Demand, is available to download here.

Resilience, space weather, and the end of the world

Animation courtesy of Spaceweather.com

Animation courtesy of Spaceweather.com

Last week you may have caught the news of two large coronal mass ejections (CMEs) occurring within a few days of each other, hitting Earth with a good dose of radiation. The two CMEs were the result of the catchily titled AR2158 sunspot, and their power was placed within the ‘extreme’ bracket of the scale used by astronomers.

On the night, many people saw the beauty in the event – thanks to it resulting in a fantastic Northern Lights display – whilst others predicted that it would lead to a nightmare of doomsday proportions.

In the end, the only ones really impacted were amateur (ham) radio enthusiasts. The HF signals used in ham radio transmissions propagate by ‘bouncing’ off the ionosphere, the atmospheric layer impacted by geomagnetic activity. This is a good thing for amateur radio enthusiasts, allowing communication over much longer distances than usual.

It was therefore far from the cataclysmic existential risk some had made it out to be – but there is just cause for concern, thanks to the potential future impact of such an event on wireless, and the consequences for wider society.

The most famous solar event is the Carrington Event of 1859, a powerful solar storm that produced the largest geomagnetic storm ever recorded. Aurora Borealis sightings near the equator were noted, whilst a famous anecdote states that gold miners in Denver woke up at 1AM and began their morning routines due to the brightness.

We’ve seen written testimony discussing Northern Lights events like this throughout history; the reason the Carrington Event is remembered is partially due to our increased understanding by 1859, but also the impact on the early telegraph systems we had by this point. These systems failed, pylons sparked and operators suffered electric shocks.

Fast forward to 2014, and we are witnessing another peak in solar activity.  After a major solar superstorm narrowly missed Earth in 2012, a NASA study in the December 2013 edition of Space Weather estimated the chances of a Carrington-level event hitting earth by 2022 at 12%.  That said, I’m dubious of how you assign statistics to something that has only happened once.

Such an event could induce huge currents in east-west wires – the longer the wire the bigger the effect. That could cause significant disruption in USA and continental Europe – though less in UK where our powerlines mostly run North-South. Transformers failing, power networks collapsing, fires and other unpleasant effects could result. With no power water supplies and sewage systems  - and of course communication networks – could stop working if not specifically design to take such effects into account.

However, just as we take into account and mitigate risks of terrorism to wireless infrastructure, the impact such an event could have on communications infrastructure is something we must take in to account when planning wireless.

Why? A 2013 report from Lloyd’s investigating the risk of such a storm estimated between $0.6 – 2.6 trillion in costs from US power shortages alone, with lower end estimates relying upon utility businesses being prepared for an event.

We contributed to arguably the most authoritative study on this issue: a report by a Royal Academy of Engineering committee on the impacts of so-called Extreme Space Weather on engineered systems and infrastructure. This included a group of eminent space scientists together with representatives of major services such as power networks and aviation, with Real Wireless representing the interests of wireless communication networks.

One interesting finding was that, although Carrington events are very extreme, even more typical activity should result in measurable impacts on mobile network quality around once a week. We recommended that systems needed for critical applications should carefully examine their use of synchronization systems based on GPS, which could be vulnerable.

The full report is available here.

We can’t prevent such an event, it will probably happen one day in the not too distant future, all we can do is ensure we are prepared to mitigate any impact it may have. We hope that the Royal Academy of Engineering report will provide a basis for proper planning to minimise the potential consequences.