Airwave goodbye, hello ESN

The government recently announced plans that – despite facing delays and setbacks – a new Emergency Services Network (ESN) will be phased in from the beginning of 2019. It will replace the legacy infrastructure, Airwave, a radio-based terrestrial trunked radio (Tetra) network.

Now, Tetra, and similar professional mobile radio (PMR) networks, are a common approach to public safety comms the world over, delivering reliable voice services, basic messaging, and providing effective coverage over great distances. Tetra can carry data traffic, but is not appropriate for large data packet transmission, as it supports only narrowband connectivity and kilobit throughput rates.

ESN on the other hand, can provide multi-megabit per second data rates and multimedia capabilities as well as traditional voice and messaging services. Its completion (date TBC), will make the UK the first in the world to deliver critical voice and data for emergency services over a 4G network. Police, fire and rescue, and ambulance services will be able to take advantage of these services from early next year, with voice capability available at a later stage.

This will also be of a far higher quality than the legacy system, as LTE can change modulation and adapt it to the signal link quality, ensuring that even in bad link loss conditions, the network will continue to provide a voice or low-data connection. Emergency service personnel will be equipped with a multi-feature handset – the result of a £210 million government contract with Samsung – which will also include a ‘push-to-talk’ function, effectively turning them into enhanced radios.

The introduction of data services to the consumer and enterprise markets has been transformative – just think about how often you use WhatsApp, share images and videos, send voice notes and conference call over IP, for example.

In that light, it is hoped that digitalised communication and data services will also be a game-changer for the emergency services. Paramedics will be able to send videos and images to A&E staff to allow them to more effectively prepare for patients’ arrival. Police officers – many of whom are now equipped with body-worn cameras – will be able to live stream video. Real-time content transmission will be used to aid satellite surveillance.

A challenging transition

This sounds great, but the roll-out has not been without its challenges. Work has begun to build the first mobile mast for the network, near Lockerbie in Scotland, but the entire network is a while off completion and an exact end date hasn’t been specified.

Behind schedule and over-budget, completing the build of the standalone public safety network will likely take between five to 10 years. Network operator EE is developing a dedicated core system to support ESN, including hundreds of 4G sites to expand coverage in rural areas, while 800MHz spectrum will be deployed across thousands of other locations. The additional functionality like push-to-talk and group chat functionality, will require new core, signal processing and radio interface protocols to be developed, tested and deployed. It’s therefore of little surprise that the government has been hesitant to confirm a date for the voice services element of ESN to be fully up and running.

A second challenge concerns coverage. As a public safety comms network, coverage must be ubiquitous, allowing emergency service personnel to communicate wherever they are. This is less of an issue for the legacy Tetra system, which uses low frequency, narrowband 400MHz spectrum, which delivers effective coverage and in-building penetration in almost any environment.

ESN’s 700MHz, on the other hand, has less range and penetration, which could compromise communication in areas like basements, tunnels, caves, and remote rural locations – just the kind of areas where the public are potentially at greatest risk of an incident!

Coverage is also a concern for those who’ll actually be using ESN – emergency services personnel. In a survey conducted in 2017, individuals from police forces, fire authorities and ambulance trusts ranked network coverage as number one in their list of concerns regarding the transition to the ne network.

Rapid response required

Networks must be densified in order to provide coverage in hard to reach areas, and building owners (modern building infrastructure can also impair coverage) must ensure that they invest in in-building coverage solutions which deliver scalable, affordable LTE public safety communications in these challenging environments. The same goes for road and rail tunnels. Public safety comms solutions must be flexible and straightforward to adapt and upgrade, dependent on regional requirements.

Pushing back the original date of deployment was a wise – if unavoidable – move by the government. In the meantime, we’ll see a phased deployment, which will involve a hybrid Tetra and LTE network – an approach which Britain is not alone in taking. South Korea’s LTE public safety network – which is mid-deployment – is interoperable with legacy Tetra equipment, and in France, an LTE network is being built which will share Tetra’s current infrastructure.

The project is an ambitious one and challenges are to be expected. However, these can be overcome with time and through considered investment in innovative new network coverage solutions. The government has estimated that ESN will result in annual savings of £200 million, yet these will only be realised once Airwave has been fully replaced.

Time is ticking, and although many members of the public won’t have heard as much about LTE ESN as they have 5G, this is still public money and government time that many will be keeping a close eye on. The government and private sector partners must work hard in 2019 to ensure that the ESN can deliver on the price point and performance promised.

This is a guest blog post by Ingo Flomer, vice president of business development and technology at Cobham Wireless

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