Airwave tackles network traffic spike on New Year’s Eve

Emergency services comms supplier Airwave records its most concentrated network usage ever in central London on New Year’s Eve

Airwave, the supplier behind the terrestrial trunked radio (Tetra) communications network used by the emergency services, recorded some of the highest traffic volumes ever seen across its central London network during the New Year celebrations.

Airwave, which is involved in the tender process for the Emergency Services Network (ESN) set to replace the current comms system from 2017, reported a 32% increase in call volumes compared with 31 December 2013.

During the 24-hour period from midday on 31 December 2014 to midday on 1 January 2015, it recorded 2.15 million calls on the Airwave network in London, with 615,000 in the central event area where the New Year’s Eve celebrations took place.

At its busiest, 139,000 calls were made in London in one hour, over 50,000 of them in the main event area. London Ambulance Services director Jason Killens tweeted that he had received more than 100 emergency calls between midnight and 12.15am.

By comparison, on a normal day the network might carry around 30,000 calls in central London, and 12 months earlier it saw 105,000 calls in the busiest hour.

The spike in traffic volumes came in spite of major changes made to London’s New Year’s celebrations by mayor Boris Johnson. Whereas in previous years around 500,000 people crammed into the central area, this year just 100,000 paying ticket holders were allowed in to watch the 11-minute display centred on the London Eye.

Extra capacity

New Year’s Eve is Airwave's second largest annual event in London, after the Notting Hill Carnival. Planning began in November 2014, when network operations director Martin Benké first sat down with the Metropolitan Police, the British Transport Police and the London Ambulance Service to co-ordinate their network requirements on the big day.

Although Airwave’s network is always configured to provide dedicated and flexible capacity, at special events where use is substantially above the norm it first tries to gauge how the emergency services will be using the network, how many operatives are likely to be on the ground and how many talk groups they will want.

Following this stage, Airwave will perform any needed software tweaks to its base stations, as well as physically installing extra radios if necessary. It has around 100 base stations in London, 25 of them in the city centre, although it cannot reveal their precise locations.

Naturally, the plans put in place “rarely survive first contact with the enemy”, said Benké, so on the big day itself, Airwave’s team members have a number of tricks up their sleeves to help things run smoothly.

These include real-time traffic monitoring, which allows Airwave to check that nobody is using network capacity who shouldn’t be.

In the past, noted Benké, it has observed police officers from other forces bringing their radios into central London and using them. If it detects this sort of activity, it has the ability – subject to permission from the customer – to temporarily block the offending radio terminal from the network.

When traffic volumes really begin to spike, Airwave can make its radio base stations more sticky, meaning it will transfer traffic from a busy site to a less busy site if needed.

It can also shut off channels in areas where the network is less urgently required, such as suburban areas, and use the free spectrum to offer more capacity in the city centre.

Because of the new ticketed format introduced for the 2015 New Year's Eve celebrations, Benké said Airwave faced additional challenges.

“We had to configure the network in a different way, because people were in a different place and the crowd was controlled,” he said.

However, he added, network configuration and control around big events is something that Airwave has provided many times over the years, and rehearsed over and over.

“The network performed entirely as anticipated. It was very busy, but there was no congestion and no service outages. It was described to me by London Ambulance as a quiet New Year's Eve in terms of support interaction with us,” he said.

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