ESN: Network Coverage, Availability & Resilience

We recently surveyed emergency services professionals about various aspects of the transition to ESN. You can view the results here.

Unsurprisingly coverage, availability and resilience ranked as most important from a network perspective. Our latest blog post explores the current status of these areas.

About ESN

The emergency services and other public safety organisastions in the UK currently use a dedicated national communications network known as Airwave, which is owned by Motorola. This is due to be replaced by an upgraded Emergency Services Network (ESN). The Home Office has contracted the mobile network operator EE, part of the BT Group, to deliver ESN coverage for the whole of the UK over its 4G network.

Replacing the existing Airwave network, EE will upgrade over five hundred Long Term Evolution (LTE) or 4G base stations across the twelve UK ESN regions, starting in the North West of England and finishing with the South East. By 2020, the ESN network will support over 300,000 users and over 35,000 vehicles will be fitted with new in-car systems. The network will allow the emergency services to access an increasing range of voice, data and video services, which will include priority calls, enhanced security, mobile push-to-talk, Voice over LTE (VoLTE) and video over LTE. VoLTE can connect calls up to twice as fast as the current methods and, as 2G and 3G connections will still be available, whenever there is no 4G signal, it simply means that there’s greater mobile coverage overall. Currently, places with a 4G signal but no 2G or 3G are unable to make or receive calls without VoLTE.

Network Coverage

EE has grown its 4G geographic coverage from 50% to 75% in 2016, and now passes over 80% of the UK. By the end of 2017, EE will cover more than 92% of UK geography with 4G and has an ambition to cover 95% of UK geography with 4G by 2020. Airwave currently covers over 97% and EE has committed to at least match this for the ESN.

By the end of 2017, EE will cover more than 92% of UK geography with 4G

According to BT, EE is investing £1.5m per day and upgrading more than one hundred sites to 4G every week. Some of those hundred sites per week add new coverage and some increase signal strength, capacity and reliability in areas with existing coverage.

Rural Coverage

EE is also rolling out a further 3,000 sites using low frequency 800MHz spectrum. The lower the frequency of the band, the further it can travel. This means the 800MHz band is the most adept bandwidth-type available for travelling over long distances, which means users can get a 4G signal even when they’re a long way from a mast. This becomes particularly useful in rural areas where masts are likely to be spread out.

EE also continues to invest heavily in innovation, looking at ways of connecting some of the most remote parts of the UK, particularly where temporary disaster coverage may be required.

EE has recently deployed its balloon-powered air-mast technology for the first time in a live setting, using the ‘Helikite’ to deliver 4G and Wi-Fi to competitors and spectators at a mountain biking event in Wales. The Helikite is a helium balloon equipped with mini mobile antennas linked to a ‘network in a box’ on the ground via 26GHz millimetre-wave (mmWave) spectrum. This allows for high capacity and low latency, enabling applications like push-to-talk and providing real world speeds of 65Mbps (although this could increase with different backhaul.)

Drones could be used alongside 4G balloons to help provide coverage.

Drones could be used alongside 4G balloons to help provide coverage.

This development is supported by the use of drones equipped with mini sites, each including a base station and antenna, which can be used to provide targeted coverage in rural areas.

These drones could eventually be used in search and rescue operations. Alongside the 4G balloons, they could provide 4G coverage in permanent sites that have been damaged,  enabling the ESN to aid disaster recovery, such as responding to floods.

Similarly their new 32 Rapid Response Vehicles (RRV) can even deploy a large temporary mast (picture right), which if necessary can be connected back to the main network via a Satellite backup from Avanti for emergency situations or to cover essential maintenance of the network.

Large temporary masts could also be used if needed.

Large temporary masts could also be used if needed.

London Underground

The current contract with EE does not cover the London Underground or DLR networks, which need to be included by the end of 2018 to start transitioning users from Airwave to ESN in London from January 2019. That being said, Transport for London (Tfl) has been working with the Home Office and EE since 2014 to design a 4G infrastructure on the Underground capable of carrying ESN and to agree appropriate funding. A pilot of a 4G mobile network began earlier this year on the London Underground, to ensure it can make the ESN available to emergency responders in stations and tunnels on the underground network in the event of an incident.

All parties are confident in the technology itself, but costs, rollout timeframes and the contract itself seem to be areas still to be worked through.

Availability & Resilience

EE’s contract will see it build more than four hundred new 4G sites and develop a “resilient” core system to support the ESN across the UK. The network will be able to prioritise ESN traffic when required, and EE with partner Avanti will introduce satellite cellular backhaul to over nine hundred fixed base stations and portable base stations across the UK for hard to reach areas, as well as fixed backhaul elsewhere.

The network will be able to prioritise ESN traffic when required

According to RootMetrics, the leading mobile performance information provider:

“In the first half of 2017, EE’s performance was still the strongest amongst all operators at the UK level, but it wasn’t as good as the performance levels we’ve seen from the operator in the past. EE’s VoLTE launch should lead to faster call setup times, vastly improved voice quality, as well as stronger call, reliability, and overall performance results in the relatively near future.”

There is no doubting EE’s commitment to make the ESN work, but there are still many hurdles to overcome before confidence levels across the industry are high. It is expected that further government updates will be forthcoming in the near future as to progress made, but delays are expected.


BT Wholesale, Transport for London, EE, ISP Review, Avanti, RootMetrics - First Half 2017 UK Mobile Network Performance Review