Hospitals have been one of the main users of Wi-Fi networks, so far. Driven by a mobile workforce and an environment where cellular devices are usually forbidden, they have accepted centralised Wi-Fi switches before many other markets. Now a London hospital has installed a wireless network which claims to do away with the need for those centralised switches.

Barts Hospital in London , part of at National Health Service (NHS) Trust which also includes The London Hospital, has installed Wi-Fi access points from Aerohive that manage themselves in a co-operative network, without a central switch.

"We have a high density of access points, so we can voice services and location," said head of ICT client services Doug Howe. The Trust has installed 77 access points in its accident and emergency department and in two newly-refurbished wards handling traum and neurology.

Building Wi-Fi in

The Trust had very little Wi-Fi despite the technology's popularity in the health sector. "We had some Wi-Fi in operating theatres, to allow computers on wheels," said Howe. But with a major refurbishment underway, the Trust decided to use 21st century networking, he said, and invited tenders to unwire a chunk of Barts.

The trust is involved in two big building projects. Barts has a new site opening in 2010, and the Royal London has a rebuilding going on to finish in 2016. The Wi-Fi wards at Barts are a trial run for potential deployment at these sites, said Howe: "These are long wards with small rooms, very like those in the new buildings."

The £300,000 pilot represents about a twentieth of the whole Trust, he said, and is initially specified to last three months, though this already looks like being extended.

Aerohive's approach contrasts with conventional Wi-Fi wisdom, which says the best way to manage a wireless LAN is a centralised controller. Access points installed throughout the area communicate with each other and create a co-operative wireless network.

Why not use a switch?

Barts chose it in competition with centralised solutions offered by BT, using Cisco's switch, and Enterasys, its wired network provider, which uses Trapeze's wireless switches. "The decision was based on performance and administration," says Howe. "With no controller, there is less work involved in running the Aerohive network." Aerohive also has relationships with Vocera, Aeroscout and Philips for the applications which Barts is using, he adds.

Surprisingly, the Aerohive network was pitched by Hewlett-Packard, which has its own centralised Wi-Fi switch, based on technology from Motorola's Symbol subsidiary. Howe doesn't think we should read anything too much into this: it's HP's professional services division in fact, which has a free hand on technology to use.

The network will be used for three classic health service applications: Vocera active badges, which provide location services and voice telephony for staff;active RFID tagging for important clinical equipment using active Wi-Fi tags from Aeroscout; and Mobile Clinical Assistant (MCA), a special-purpose Wi-Fi connected PDA from Philips to support medical staff.

The system has 77 access points, supporting around 75 Vocera badge users in the three locations. This is quite a dense deployment of access points, which is necessary for voice applications and for location services, explains Howe.