WLAN project speeds urgent care: BellSouth’s 168-access point wireless network delivers bottom line gains
St. Vincent’s “hospital of the future” is on its away.
Using Cisco Aironet 350 Access Points (APs) and WaveLINK MobileManager to manage the network, St. Vincent’s Hospital of Birmingham, Ala, enhances “patient touch” by enabling multiple care applications and devices. St. Vincent’s WLAN serves patients through applications like a physician’s portal (with patient information, accessed on PDAs) and in-room registration (on Tablet PCs).
St. Vincent’s deployment is unique. “I’m not aware of any other hospital that is using this combination of tablets, PDAs, laptops and wireless VoIP badges all over the same network, covering the entire campus,” says Tim Stettheimer, chief information officer, St. Vincent’s. The badges, from Vocera, enable two-way communication between medical staff.
The 802.11b protocol was selected for its compatibility with the largest number of devices. Cost considerations included the APs, management software and wireless devices as well as planning, design and custom software.
It was the network’s potential usefulness that justified costs rather than ROI. “We are in the clinical outcomes business. We are always looking at what we need to do to take that next step to improve care, safety and outcomes,” says Stettheimer.
St. Vincent’s determined that mobility, married to information availability, would advance these initiatives. The technology that would enable that was wireless. For example, the hospital’s existing clinical data repository is available through the physician’s portal, which can be accessed wirelessly.
Physicians carrying 802.11 PDAs can view patient histories anywhere on the campus in real-time. Data available include medications, lab results, allergies and radiology transcriptions. Clinical decisions and resources converge on patient care with increased speed and efficiency.
BellSouth had deployed St. Vincent’s Cisco Enterprise Class Gigabit Backbone Network. This relationship made BellSouth the obvious choice for the WLAN project.
“Being a Cisco partner with multiple certifications, we are authorized to provide a BellSouth flavor of maintenance, backed by Cisco. At St. Vincent’s all the equipment is covered by the BellSouth maintenance plan,” says Jeff Butler, design engineer, BellSouth.
Today, BellSouth functions as a “consultative partner” to St. Vincent’s, tweaking the WLAN, adding APs and making new applications work.
One hundred and sixty-eight Cisco APs have covered and served the 1 million sq.ft. campus at St. Vincent’s for about a year now. BellSouth designed, engineered and installed the WLAN. The entire network was installed first, then powered up. Typical of WLANs, the deployment was quick, completing in about three months.
BellSouth first conducted a site survey, consisting of frequency testing. The carrier installed an AP to simulate signal and then confirmed how far coverage extended out and away from the device. Wireless coverage reaches out from an AP in a circular format around the device. This leads to overlaps, which the hospital wanted to insure adequate coverage.
Once AP placement was determined by diagramming coverage areas and frequencies, a hardware list was compiled. Hardware included the Cisco APs, and antennas that were selected based on survey results and the configuration of rooms and hallways.
The hardware was configured at BellSouth’s staging facility before shipping. Throughout the project BellSouth had stationed its project manager on-site to work with St. Vincent’s on other projects that would need to be put in place in parallel with the WLAN.
Though 802.11b only supports speeds up to 11MB, with a large chunk of that going to overhead traffic, BellSouth designed the network so that realized speeds approach 11MB by using more APs for higher density, with lower power level settings.
The WLAN is connected to the wired infrastructure. The networks are separated by a firewall. Any traffic that passes between them has been carefully constrained to permissible protocols and is monitored by intrusion detection.
Because St. Vincent’s had multiple APs above and below each other on multiple floors, it experienced bleed through caused by high power levels and APs that conflicted by running on the same channels. To resolve this issue, officials cut back the power levels and made sure APs directly atop each other used different channels.
Interference was also apparent as hospital elevators presented problems for signal transmission. Signal strength in the direction of an elevator could drop to as low as 30%. “As a solution, we were able to adjust power on the APs and give them coverage that allowed the highest throughput,” says Butler.
Application issues included MAC authentication, which was implemented as a first layer security measure. On large networks like this, MAC authentication becomes a burden because of the number of devices that need to be tracked and inventoried. St. Vincent’s is working on an alternate solution.
Device problems centered on power levels and antenna types. Different devices’ NICs and antennas have varying power levels. Antennas are directional or omnidirectional, such as those in the Vocera badges.
The job a NIC or antenna can do with the power available to it helps determine the quality of your connection. “We had to do some tweaking to make sure our coverage areas didn’t get too thin at the edges. If you were walking away from an AP with that 0 gain, omnidirectional antenna, the badge would drop your connection,” says Eddie Kilgore, information security officer, St. Vincent’s.
The badges also presented the hospital with a multicast issue. Using these badges you can contact anyone who is logged on. A back-end server initiates the two-way, point-to-point connection. You can also talk to groups, by using multicast.
From among two multicast protocols, the existing Cisco switches on the backend used the Cisco Group Management Protocol (CGMP), while the Vocera application used IGMP snooping. This created a conflict. “The multicast couldn’t cross the switch,” says Kilgore. According to Kilgore, if you sent a multiple call and everyone was associated to an AP on the same switch you were on, they would get the message. If they were associated to an AP that was on another switch, they wouldn’t. Vocera recoded the application to use CGMP.
St. Vincent’s has emerged as one of the pioneers in the direct application of wireless technologies to hospital-based patient care.
Project: St. Vincent’s chose to add a campus-wide wireless network with lots of overlap and a high QoS to enable real-time, anywhere information access for its medical constituents.
Execution: BellSouth was hired to conduct a site survey, then diagram, design and install an 802.11b network. BellSouth laid out frequencies and coverage areas and ordered Cisco Access Points (APs) and other hardware. It configured the APs and shipped the hardware to the site, and then installed and brought up the network in 12 weeks. All troubleshooting was done by BellSouth’s CCIEs (Cisco Certified Internetwork Experts).
Implementation: The 802.11b network was assembled and connected to St. Vincent Hospital’s existing wired network; the two networks run in parallel. Multiple applications were employed for improved patient care. These include in-room registration on TabletPCs, Voice over IP (VoIP) communication with multicast on Vocera badges and physician, staff, and patient information portals. Other devices include a wide variety of PDAs, laptops and other hardware. The network is open to doctors who want to bring in their wireless device of choice.
Business case: Hospitals, like universities, build their business cases on value to constituents rather than ROI. A genuine increase in the speed, quality and efficiency of patient care was expected and realized. The cost of the project and first year’s maintenance (about $1 million) was neither negligible nor prohibitive.
Our read: St. Vincent’s has improved the patient care experience at reasonable financial and other costs. Occasional down time for bug fixes has been a good trade-off for increased time, cost and human resource savings.
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