Hospital wireless network planning requires thinking ahead

Anyone planning a hospital wireless network must anticipate future needs. This can mean more access points, WPA2 encryption and distinct lanes for different types of traffic.

In just a few years, the hospital wireless network has gone from a nice-to-have add-on to an indispensable IT infrastructure workhorse carrying far more traffic -- and more kinds of traffic -- than was ever imagined. If you are planning a hospital wireless network today, you have to design it at industrial strength -- and then some -- or risk a costly retrofit later.

"By the nature of the business, wireless becomes your primary network. Your nurses and doctors are moving around. And tracking devices via radio frequency identification (RFID) will be a huge part of a hospital operation," said Jack Santos, an analyst at research firm Gartner Inc. and former CIO at Catholic Medical Center in Manchester, N.H.

A Wi-Fi network must not only enable guest and patient Internet access, but also securely transport electronic health records (EHRs) to and from mobile workstations, Voice over Internet Protocol, or VoIP, calls, foreign-language translation services, basic images and, as Santos said, RFID-based real-time location systems (RTLS). It's a tall order.

Throw Wi-Fi network design rules out the window

Any hospital wireless network must begin with a thorough site assessment -- and hospitals are sites like no others. Experience has shown that the Wi-Fi network design rules that apply to typical office buildings must be thrown out the window when a hospital wireless network is being planned.

"The biggest issue at first is doing proper surveys. You need to find out where the interference is and on what channels, and build your network from there," said Tom Cotter, enterprise network advisory specialist at Memorial Sloan-Kettering Cancer Center in New York.

Hospitals were never designed with wireless networks in mind, noted Zac Bujnoch, an analyst at research firm Frost & Sullivan in San Antonio. Convoluted floor layouts in buildings that may be a century or more old are just the beginning of the problem. Hospitals are replete with Wi-Fi signal-blocking stainless steel equipment and medical devices that may emit radio frequency interference. Experience has shown IT managers need to allow plenty of time -- weeks or months, depending on the size of the facility -- and to expect the unexpected.

For Cotter, home Wi-Fi networks in New York's Upper East Side presented problems for Memorial Sloan-Kettering. "We have several apartment buildings right across the street. A few years ago, everyone was buying [Wi-Fi equipment] and transmitting at maximum strength. We saw some interference issues, so we had to adjust the power levels and adjust coverage," he said.

Santos experienced Wi-Fi interference issues of a different sort. "When we deployed a wireless network in the emergency room, in one corner -- and it was an important spot -- we had a hard time keeping signals alive. It was because the automatic door mechanism interfered with the signal for the wireless network," he said.

Hospital wireless networks need 1,000 points of access

A hospital cannot have too many wireless access points. Medical facilities can require double, even triple, the number of access points that are typical of other installations.

Four years ago, The Ohio State University Medical Center (OSU) began a major wired and wireless network upgrade for a number of hospital and academic buildings encompassing 5 million square feet. After a year of planning, OSU launched blanket wireless coverage.

"We did an extremely dense implementation. Cisco recommends 3,000 square feet per access point. We did one per 1,000 square feet -- and more in some places -- based on the anticipated density of wireless devices," said Chad Neal, director of technology at Columbus-based OSU.

"We covered all clinical areas with the same coverage. We also have coverage in tunnels, where we have robotic carts that handle trash, dishes and linen. We worked very closely to engineer the wireless specs of 'how many access points' and signal strength. We wanted overlapping 'pancakes' of coverage," Neal explained.

Implementing security, traffic controls on hospital wireless networks

Because hospital wireless networks are carrying patient medical data, IT pros must ensure the traffic is encrypted, as mandated by the Health Insurance Portability and Accountability Act (HIPAA). Today that means implementing Wi-Fi Protected Access (WPA2) encryption. WPA2 has superseded Wired Equivalent Privacy, or WEP, encryption, which can be readily broken by knowledgeable hackers.

In addition to WPA2, hospitals often implement intrusion detection systems from such providers as Fluke Corp. (AirMagnet), Motorola Inc. (AirDefense) and AirTight Networks Inc. The companies have all developed extensive reporting mechanisms that conform to HIPAA requirements.

Because hospital wireless networks are asked to carry such a wide variety of traffic, distinct travel lanes must be provided for each type, whether it be guest and patient access, medical records and basic images, medical equipment information, or RTLS data.

Generally, traffic is segregated and assigned to one of several virtual private networks across several different Wi-Fi channels. For example, because Wi-Fi chips now are built into such medical equipment as infusion pumps, those clinical systems are best kept on a separate channel or virtual local area network (virtual LAN), Santos noted. "You don't want that to interfere with the data network," he advised.

We worked very closely to engineer the wireless specs of "how many access points" and signal strength. We wanted overlapping "pancakes" of coverage.

Chad Neal, director of technology, The Ohio State University Medical Center

While extremely high-resolution medical images cannot be carried effectively over today's Wi-Fi networks, basic images at lower resolution are often sent with medical records, which should be on their own separate virtual LAN or channel. These records and images sometimes show up at patients' bedsides on mobile PCs known as COWs (computers on wheels) or WOWs (workstations on wheels) -- medical workstations that can be moved from one bedside to the next and require reliable Wi-Fi network access wherever they happen to be.

Many institutions also are implementing RTLS from a number of vendors, including Ekahau Inc. and AeroScout Inc., to track expensive equipment, such as WOWs, COWs, infusion pumps, X-ray machines and monitoring devices. Taking RTLS a step further, Ekahau recently announced a partnership with Polycom Inc. to enable location tracking on Polycom's SpectraLink 8000 Series Wi-Fi handsets. This will let nurses and doctors reach one another by phone and understand their relative locations.

Any RTLS implementation must assume a steady increase in the number of devices to be tracked. Memorial Sloan-Kettering is implementing an AeroScout system that tracks 8,000 tagged devices now but will cover 12,000 tagged devices next year, according to Cotter.

Finally, despite the increasing reliance on Wi-Fi networks, no hospital can do without a high-bandwidth wired network. High-resolution medical images demand it, and the wired LAN provides essential redundancy for the hospital wireless network.

Stan Gibson is a Boston-based contributing writer. Let us know what you think about the story; email editor@searchhealthit.com.

This was first published in January 2011

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