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Hoglund and Varga: Building a Reliable Wireless Medical Device Network

I’m adding Wi-fi patient monitoring to my hospital Multiple points of failure potentially exist to either
network. How can I design wired and wireless redundancy cause dropout of the signal or the introduction of noise
into the network?
into the system as whole. This could result from a bad
The practices for designing redundancy into a network connection, removing an antenna, adding an antenna,
do not change by adding patient monitoring. Standard relocating an antenna, or a receiver section failing. This
networking practices which can be planned in conjunc- coaxial WMTS antenna design is what is considered to be
tion with hospital networking staff and/or third-party “non-intelligent”. It is simply an active powered coaxial TV
providers will meet your needs. Most WLAN vendors have based diversity antenna infrastructure that is connected
capabilities for High Availability (HA) for their WLAN to powered telemetry receivers.
controllers (WLC) and offer near zero failover time to a Unlike with WLAN, no software exists in a WMTS design
secondary or tertiary WLC. In addition, modern WLANs to actively monitor the air space for interferers or adjust
can automatically modify the WAPs output power to in- power for changes in WLAN signal coverage. Nor are there
crease the surrounding WAPs cell coverage in the event provisions for redundant failover of receivers (in case
of WAP malfunction. a receiver fails). In addition, the network management
Although the network access-layer is typically not for a patient monitoring system operating on a WLAN
configured for redundancy, the access layer switches will be absorbed into the overall network management
generally will, in healthcare facilities, have redundant costs as the patient monitoring system is operating on
Ethernet connections to the core network. a common network infrastructure versus a proprietary
WMTS-based system.
Are there differences in the way redundancy works
with Wi-fi wireless monitoring compared to monitoring CoNCLuSIoNS
suppliers that utilize WMTS?
1. Wi-Fi is safe and reliable for patient monitoring.
The principal difference is that redundancy can be
2. The key to success is in the design, implementation
cost-effectively built into an 802.11 wireless network.
and management of the network.
Due to the proprietary nature of WMTS telemetry antenna
3. Wi-Fi opens the door to unprecedented benefits to
systems, it is either technically impossible or too costly
the hospital, such as the ability to monitor a virtually
to design redundancy into the system.
unlimited number of patients house-wide, improved
WMTS, or realistically all “telemetry” antenna and patient mobility, significant cost savings and more.
receiver designs, use antenna diversity: if there were a
4. Wireless monitoring gives hospitals the ability to pro-
null (lack of signal) from one antenna, the other adjacent
vide continuity of patient care across the enterprise
antenna may likely receive the signal. However, this is highly
for the entire patient stay, which is only financially
dependent upon the quality of design which is more of an
feasible with Wi-Fi.
art, versus a proven, scientific WLAN enterprise design.
Several things need to be taken into consideration for ABouT THe AuTHoRS
a WMTS implementation. Upon installation of a WMTS
DAvID hogLuND, President and CEO of Integra Systems,
antenna system, it must be balanced. These coaxial an-
Inc., has more than 30 years of experience in patient moni-
tenna designs consist of splitters, power supplies (to toring networking and has authored over 20 white papers
supply power to the specific legs of the antenna system), and publications. (www.integrasystems.org)
attenuators, exact cable lengths, and connections. In large
vINCE vARgA, Business Development Manager for Mo-
designs this could amount to thousands of connections
bility at Global Technology Resources, Inc. has over 13
and hundreds of antennas, which have be at the exact years of experience in wireless networking technology,
right place and with the right connections made with the worked with clients across multiple vertical markets, and
ultimate two home runs to the receiver sections. has managed more than 40 wireless LAN patient monitor
deployments at healthcare facilities across the US since
2004. (www.gtri.com)

49 J Global Clinical Engineering Special Issue 1: 42-49; 2018