










































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

Publicly available March 12, 2014, revised March 22, 2018.

Building a Reliable Wireless Medical Device 
Network 

By D Hoglund,1 and V Varga2

1Integra Systems, Inc.
2Global Technology Resources, Inc.

ABSTRACT

How to design and test the most effective and secure wireless medical device connectivity applications that will 
provide the true mobility experience that is needed in the 2018 healthcare marketplace. Today’s medical devices 
will need to be connected to provide the data to the electronic medical record. This connectivity will be either real 
time or on a non real time basis. In either case; the majority of this data transfer will move toward a wireless medium 
from a legacy wired connection. The following will discuss best practices for wireless network design based upon 
application requirements; but also the protection of any data regarding cybersecurity requirements. The author has 
over three decades of medical device knowledge sense but also two decades of wireless and security integration 
knowledge sense. The take away is to understand the best practices and how to apply this to product design and the 
overall enterprise implementation into the healthcare ecosystem of connected devices. 

Keywords – wireless, WLAN, network, acute care, patient monitoring, IEEE802.11, WMTS, telemetry.

INTRoDuCTIoN

A brief history of the WLAN-enabled medical device.

Historically, patient-wearable monitoring – commonly 
referred to as telemetry – required its own custom de-
signed and proprietary radio system and coaxial cable 
infrastructure for unidirectional communication. This infra-
structure was built around regulatory domain-controlled 
technologies, such as Wireless Medical Telemetry Service 
(WMTS) in the United States. While these designs proved 
to be reliable, they were often expensive, unique to each 
manufacturer, and lacked enterprise management and/
or troubleshooting capabilities. These telemetry systems 
were generally confined to individual care units within 
the healthcare facility and utilized several to 100 or more 
dedicated telemetry patient channels.

For the past several decades networked bedside (or 
acute care) patient monitoring was confined to propri-
etary, standalone networks for communication from the 
bedside monitor to the central station. This was, and is 
even today, often the de-facto standard methodology in 
the majority of critical care units on a global basis.

Over the past decade, many medical device manu-
facturers have incorporated WLAN in their devices for 
a multitude of use requirements. This has included the 
next generation of smart infusion pumps, portable patient 
monitoring, and within the past five years, telemetry.

Modern enterprise networks, both wired and wireless 
Ethernet systems, have progressed to the point where they, 
if designed and installed correctly, have proven to be cost 
effective and reliable – as demonstrated by hundreds of 
thousands of mission-critical WLAN networks deployed on 

https://www.globalce.org
https://www.globalce.org


Hoglund and Varga: Building a Reliable Wireless Medical Device Network

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

a global basis in many industries. As a result, both medi-
cal equipment manufacturers and healthcare institutions 
are looking to leverage their nearly ubiquitous WLANs 
by utilizing them for network-enabled medical devices.

Clinical benefits of having a WLAN throughout the 
healthcare institution

The healthcare industry was an early adopter of WLANs 
because they enabled more timely and accurate bedside medical 
statistics recording, voice-over-IP-over-Wi-Fi, asset location, 
and guest Internet access – which benefitted clinicians, IT 
and biomedical groups, as well as patients and their families.

This new methodology of networked patient monitoring 
has many clinical benefits. Specific to telemetry and patient 
monitoring, an omnipresent WLAN can now enable the 
following:

• Expansion of telemetry area coverage: The telem-
etry system can operate across the entire facility, 
and not be limited to specific care areas. The trend 
is to increase telemetry usage across a common 
enterprise network, versus managing hundreds of 
standalone monitors.

• Increased reliability: Patient monitoring can leverage 
proven networking technology that is consistent in 
design and deployment. This networking infrastruc-
ture can provide true bi-directional communication 
for increased overall system reliability. 

• Increased space utilization and patient safety: 
Having all monitors networked through the WLAN 
gives the hospital the flexibility to monitor patients 
anywhere in the hospital. For example, if the Emer-
gency Department is at capacity, they can add extra 
monitored beds in another unit, thereby keeping 
the patient in the delivery network, versus having to 
divert the patient to another facility because of the 
lack of monitored beds. Having additional monitored 
beds also enables hospitals get patients out of higher 
acuity, and higher cost, settings.

• Reduced risk of undetected events: For example, 
if a prior cardiac patient comes in for an orthopedic 
procedure, the orthopedic nurse could easily have 
a cardiac trained nurse observe that patient using 
WLAN monitoring while the patient is being treated 
for that orthopedic procedure.

SuITABILITy of WLAN foR PATIeNT 
MoNIToRINg

overview

Any wireless network is dependent upon proper plan-
ning, design, and implementation, taking into consideration 
the internal and external variables that may impact the 
network’s performance and reliability. Such internal and 
external factors include high availability (HA) network 
infrastructure, radio frequency (RF) interference, Qual-
ity of Service (QoS) requirements, and cost budgets. In 
terms of suitability of the WLAN for patient monitoring, 
the healthcare institution must consider the requirements 
of the specific applications that will run over the WLAN. 
Any patient monitoring network has to be 100% reliable 
around-the-clock, 365 days a year, while communicating 
alarms, events, and recordings in real time.

Suitability factors

The following factors influence the suitability of a 
WLAN to support a patient monitoring system:

• Design of the WLAN: Over the last 15 years, WLAN 
design has migrated from a simplistic paper-based 
approach to a very scientific methodology utiliz-
ing computer-based predictive modeling tools and 
onsite RF spectrum analysis to identify the sources 
of any potential RF interference. This methodology 
takes into account building materials, client device 
density, Wireless Access Point (WAP) placement, 
antenna patterns, RF link speeds, and RF channel-
ization/ power and then creates a predictive model 
with 98% to 100% accuracy of design. In addition, 
a proper logical design must be created to define IP 
addressing, VLANs, multicast, DHCP, QoS, and other 
network-layer settings that affect WLAN quality and 
reliability. When using these tools, the hospital can 
have confidence that the network they install will 
need little to no modification after installation.

• Installation and troubleshooting: A well planned 
and designed LAN and WLAN is the foundation for 
a well performing patient monitoring system. As 
mentioned above, predictive WLAN modeling tools 
ensure a design with over 98% accuracy before 
implementation. For the few instances where the 



 Hoglund and Varga: Building a Reliable Wireless Medical Device Network

J Global Clinical Engineering Special Issue 1: 42-49; 2018  44

WLAN design may incorrectly place Wireless Access 
Points (WAPs), WAP location modifications can eas-
ily be made in the field at the time of deployment. 
When installing a WLAN, all operational settings 
are configured in a central WLAN controller that 
interfaces with the facility’s core network and allows 
for efficient network communication. In addition, 
depending on the size of the WLAN, a separate WLAN 
management system may also be implemented to 
provide a single “pane of glass” for the management, 
monitoring, alarming, troubleshooting, reporting, 
and assurance of consistent configurations across 
multiple WLAN controllers. All of these improve-
ments make the implementation of a reliable LAN 
and WLAN scientific and predictable.

• Interference: While RF interference is always a pos-
sibility, the modern WLAN generally has spectrum 
analysis functions built into the network as a whole. 
This allows for constant monitoring of the network for 
any interference and acts to either issue an alarm to 
the network administrator or automatically mitigate 
those specific interferers. As good design practice, 
an onsite spectrum analysis should be performed to 
determine any RF interferers present in the facility 
in the 2.4GHz and 5GHz bands and their potential 
impact.

• Reliability: Today’s WLAN is an intelligent network. 
Although WAPs have a mean time between failure 
(MTBF) of over ten years, this network can auto-
matically sense and alarm if a WAP fails or is not 
performing as expected. Good WLAN design practices 
dictate overlapping adjacent WAP cells to ensure 
seamless client device roaming across the network. 
Even if an individual WAP fails, radio output power in 
adjacent WAPs can be set to automatically increase/
decrease to ensure adequate coverage. In addition, 
High Availability (HA) designs feature redundant 
WLAN controllers that will failover in a seamless 
fashion in the event of a network controller failure.

• Scalability: In the past, understanding how the 
WLAN client density may increase was a challenge. 
WLAN designs must anticipate the potential number 
of client devices such as patient monitors that will 

be used over the life of the WLAN. Today there are 
tools from such companies as Ixia (www.ixiacom.
com) that allow end users and WLAN device manu-
facturers to assess the scalability of a WLAN. Given 
the new higher-speed WLAN standards, it is common 
to build and scale networks to thousands of users 
to support data, voice, video, and WLAN-enabled 
medical devices.

• Two-way communication: Previous generations of 
proprietary wireless communication for telemetry 
was unidirectional; WLANs offer two-way or bi-
directional communication. Two-way communica-
tion supports the latest generation of patient-worn 
monitoring devices. These devices send patient vital 
signs data to the central monitoring station for display 
and alarming, as did yesterday’s telemetry transmit-
ters, but they also display and alarm locally. So, if 
the patient accidentally walks outside of the Wi-Fi 
network coverage area, the patient will continued 
to be monitored locally. The caregiver is therefore 
able to monitor the patient without compromising 
the mobility of ambulatory patients.

• Cost issues: Healthcare systems are under tremen-
dous cost pressures, so the more value that they can 
realize from a technology investment, the better. In 
the case of patient monitoring, this is yet another 
application across which to allocate the fixed WLAN 
cost. More than likely, the investment in the WLAN 
was made for Bar Code Medication Administration 
(BCMA), wireless voice-over-IP (VoIP), real-time 
location services (RTLS), and/or “smart” infusion 
pumps. Adding WLAN-based patient monitoring 
may add some small incremental costs, but this 
application can be amortized over a number years 
with the other applications to improve the return 
on investment (ROI).

Wi-fi vs. WMTS cost comparison

The costs of implementing patient monitoring on 
Wi-Fi are significantly less than on a WMTS network. 
The following cost comparison tool provides a general 
indication of costs involved.

www.ixiacom.com
www.ixiacom.com


Hoglund and Varga: Building a Reliable Wireless Medical Device Network

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

BeST PRACTICeS

The following are best practices for maximizing reli-
ability and uptime when implementing patient monitors 
on an existing wireless LAN: 

Start with the right “wireless radio design” within the 
medical device

One popular misconception that frequently compro-
mises performance is that “all IEEE802.11a/b/g radios 
are created equal.” On the contrary, the quality of radio 
devices varies, and if a medical device manufacturer 
selects a sub-par, low-cost radio, it can undermine the 
performance of a life-critical medical device that costs 
thousands of dollars. Device testing is the key to protecting 

TAbLE 1. WLAN vs. WMTS cost comparison tool



 Hoglund and Varga: Building a Reliable Wireless Medical Device Network

J Global Clinical Engineering Special Issue 1: 42-49; 2018  46

yourself from buying a device with a sub-par radio. More 
on that in the next section.

Another costly misconception is that a radio obtain-
ing a stamp of approval from the Wi-Fi Alliance means 
everything will work fine; but there’s more to it than that.

The Wi-Fi Alliance was founded in 1999, the same year 
that the IEEE approved the extended version of 802.11 
(802.11b) standard for the specific purpose of ensuring 
interoperability between client radios and wireless ac-
cess points.

The interoperability testing conducted does not include 
modeling the specific characteristics of a data, voice, video, 
or medical device client or the simulation of different 
mixed client traffic load environments; nor does it measure 
application performance. Obtaining the Wi-Fi Alliance’s 
stamp of approval is a great start, but it’s far from the end. 
The fact that a radio is Wi-Fi approved, or subscribes to 
802.11i and 802.11e, does not demonstrate how well the 
roaming algorithms will work, or assess the passing of 
security supplicants. Many healthcare institutions employ 
WPA2 or other enterprise-level WLAN security methods 
but differ in how they implement security methodologies, 
which in turn impacts device and application performance.

In selecting the optimal WLAN-embedded radio, 
device manufacturers must assess the ability of the com-
ponents to meet their intended use for quality of service, 
roaming, and varying security implementations. As the 
mobile healthcare ecosystem grows ever more complex, 
embedded radio strategies must be able to accommodate 
all enterprise-grade security strategies and effectively 
roam amidst a myriad of traffic types throughout a highly 
mobile environment.

It behooves the hospital to choose devices that contain 
radios that meet their current requirements in order to 
provide a foundation for future requirements.

Device testing: what it is and why it’s important

The device manufacturer is responsible for testing 
medical client devices during validation and verification. 
A comprehensive methodology for testing the device 
proceeds from highly controlled lab testing to assess-
ing performance in the field via open air. Testing should 
include validating components such as radios, chipsets, 

and driver firmware and, once that is completed, progress 
to assessing the real-world performance of the medical 
device itself.

Hospitals have the right to ask manufacturers if their 
devices have been tested or installed successfully in a 
similar configuration to what they are considering. The 
proven methodologies should include:
1. Base-lining network performance using “golden” clients 

to obtain a “best-case” use model
2. Base-lining device performance under ideal network 

conditions where it’s the only client communicating 
with WAPs under optimal conditions

3. Assessing range and roaming capabilities by varying 
RF signal attenuation to prompt devices under test 
(DUTs) to move away from and between specific WAPs. 
This includes:

• Determining device association to the WLAN at 
various ranges

• Measuring the accuracy of device throughput, 
latency, and packet loss characteristics

• Assessing performance as devices travel across 
multiple WAPs to emulate patient mobility. Test-
ing should progress from simple setups using only 
two WAPs at a time to complex scenarios where 
the device sees multiple available access points 
broadcasting at different signal strengths.

4. Assessing real-world performance and security by 
simulating live network conditions. Generating high 
traffic loads and interference allows the resilience, 
coexistence, and security capabilities of devices to be 
realistically and thoroughly assessed. User-configured 
clients should be generated to populate a realistic 
network ecosystem containing device traffic typically 
found in healthcare environments – voice over IP, 
data from wireless infusion pumps, wireless laptop 
transactions, video, etc. – all generating simultaneous 
network traffic.

5. Measuring interoperability with multiple WAPs and 
mobile clients and major customers’ preferred WLAN 
equipment vendors

6. Quantifying application performance and quality of 
experience (QoE) from the user perspective



Hoglund and Varga: Building a Reliable Wireless Medical Device Network

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

7. Reproducing field conditions and modeling “what if 
” scenarios in the lab to simulate individual hospital 
environments

8. Onsite assessment to ensure successful deployments 
out of the gate

9. Ongoing lab and site testing of network firmware 
changes and devices software upgrades

The WLAN patient monitoring deployment: what and why

In the area of patient monitoring, the actual patient-use 
model is critical to a successful monitoring selection and 
implementation. Before the technical requirements can 
be solved, the clinical requirements need to be addressed 
and understood, including:

• Where are the patients going to be monitored? A good 
starting point is to sit down with CAD drawings of the 
hospital floor plan and have clinical staff highlight 
all the areas where patients need to be monitored. 
For example, would a patient need to be transported 
from the ICU down the elevators to radiology and/or 
therapy areas? If so, then adequate wireless coverage 
would be needed to ensure real-time connectivity.

• How many patients are going to be monitored simul-
taneously, at maximum patient census?

• Where will the staff monitoring these patients be 
located?

Once the clinical requirements are vetted out and agreed 
to, then the technical requirements can be addressed. The 
following questions should also be discussed:

• What are the anticipated growth requirements (scale)?
• What is the current network infrastructure in place 

to support the new patient monitoring system 
requirements?

• What, if any, network remediation needs to be 
completed?

Based upon an understanding of the medical device’s 
network characteristics and the existing network infra-
structure, an accurate WLAN design can be initiated. The 

Figure 1. Wireless patient monitoring integration process

Figure 2. Example of marked up hospital floor plan, highlighting 
all places where patients will be monitored



 Hoglund and Varga: Building a Reliable Wireless Medical Device Network

J Global Clinical Engineering Special Issue 1: 42-49; 2018  48

design tasks may include creating a completely new design 
or modifying the existing WLAN. This design can be then 
handed off to the hospital’s integrator for any potential 
remediation and/or additional infrastructure.

fRequeNTLy ASkeD queSTIoNS 

Why is it common for hospitals to use Wi-fi for bedside 
and transport monitoring, but not for telemetry?

It has been easier for medical equipment manufacturers 
to design Wi-Fi into a bedside and transport monitor due 
to the looser constraints around Wi-Fi power consump-
tion and associated battery life. Portable monitors tend 
to be powered by battery and AC line power and tend to 
be used for shorter periods of time. Until most recently, 
Wi-Fi radios tended to be relatively power hungry. Telem-
etry monitoring is wearable, requiring smaller batteries 
to conserve weight and space, and has a requirement for 
the devices to be worn for days.

When I look for Wi-fi based patient monitoring, is 
the particular WLAN technology important – such as 
802.11a, b, g, n, or ac?

The evolution of Wi-Fi has been driven by the radio 
manufacturers and IEEE standards seeking increasingly 
higher performance networks with increased radio spec-
trum efficiency. Here is the history of IEEE 802.11.

What is important is to focus on the application and use 
model. Patient monitoring data throughput requirements 
are extremely low and do not need the high speed capa-
bilities of 802.11n and 802.11ac chipsets. The choice of 

radio is really dictated by chipset availability (for example, 
one would be hard pressed to find an 802.11b radio in 
2014), power consumption, and feature set required by 
the patient monitor. Wi-Fi clients built on earlier 802.11 
standards will communicate with the same QoS (Quality 
of Service) and security but simply may not be able to take 
advantage of capabilities inherent in 802.11n and 802.11ac. 
These include but are not limited to Channel Binding at 
40/80MHz, MIMO Spatial Streams and Multi-Use MIMO, 
High Modulation 64 QAM and 256 QAM, beam-forming 
and co-existence mechanisms for 20/40/80/160MHz. 
When the healthcare enterprise desires to move forward 
with 802.11n and then 802.11c, adding the low bandwidth 
requirements of patient monitoring will have little to no 
impact on the overall wireless infrastructure.

How do I know that Wi-fi will be reliable for a life-
critical medical application when the spectrum is already 
crowded with data, voice, etc.?

The evolution of Wi-Fi has been to primarily increase 
networking speed, quality of service, and security. Wi-Fi 
has evolved to a level of performance capability whereby it 
is now displacing the wired Ethernet network at the access 
layer. Those applications with low bandwidth require-
ments, such as infusion pumps and patient monitoring, will 
reliably function in the 802.11g (2.4GHz) and/or 802.11a 
(5GHz) spectrums. Since 802.11n is backward-compatible 
with both ‘g’ and ‘a’, those same monitors will work well 
in a 802.11n WLAN infrastructure. Applications such as 
high-end video will tend to migrate to 802.11ac operating 
in the 5GHz band. Therefore, all applications can co-exist 
successfully on a modern WLAN network.

Modern WLAN systems increase overall system reli-
ability using:

• Persistent spectrum analysis to identify RF interfer-
ers and proactively reconfigure RF channelization to 
work around the interference

• Applying best practices for networking design and 
deployment for Quality of Service (QoS) to prioritize 
patient monitor system traffic over other traffic types

• Applying best practices for networking design and 
deployment for network segmentation via VLANs that 
address scalability, security, and network management

TAbLE 2. History of IEEE 802.11



Hoglund and Varga: Building a Reliable Wireless Medical Device Network

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

I’m adding Wi-fi patient monitoring to my hospital 
network. How can I design wired and wireless redundancy 
into the network?

The practices for designing redundancy into a network 
do not change by adding patient monitoring. Standard 
networking practices which can be planned in conjunc-
tion with hospital networking staff and/or third-party 
providers will meet your needs. Most WLAN vendors have 
capabilities for High Availability (HA) for their WLAN 
controllers (WLC) and offer near zero failover time to a 
secondary or tertiary WLC. In addition, modern WLANs 
can automatically modify the WAPs output power to in-
crease the surrounding WAPs cell coverage in the event 
of WAP malfunction.

Although the network access-layer is typically not 
configured for redundancy, the access layer switches 
generally will, in healthcare facilities, have redundant 
Ethernet connections to the core network. 

Are there differences in the way redundancy works 
with Wi-fi wireless monitoring compared to monitoring 
suppliers that utilize WMTS?

The principal difference is that redundancy can be 
cost-effectively built into an 802.11 wireless network. 
Due to the proprietary nature of WMTS telemetry antenna 
systems, it is either technically impossible or too costly 
to design redundancy into the system.

WMTS, or realistically all “telemetry” antenna and 
receiver designs, use antenna diversity: if there were a 
null (lack of signal) from one antenna, the other adjacent 
antenna may likely receive the signal. However, this is highly 
dependent upon the quality of design which is more of an 
art, versus a proven, scientific WLAN enterprise design.

Several things need to be taken into consideration for 
a WMTS implementation. Upon installation of a WMTS 
antenna system, it must be balanced. These coaxial an-
tenna designs consist of splitters, power supplies (to 
supply power to the specific legs of the antenna system), 
attenuators, exact cable lengths, and connections. In large 
designs this could amount to thousands of connections 
and hundreds of antennas, which have be at the exact 
right place and with the right connections made with the 
ultimate two home runs to the receiver sections.

Multiple points of failure potentially exist to either 
cause dropout of the signal or the introduction of noise 
into the system as whole. This could result from a bad 
connection, removing an antenna, adding an antenna, 
relocating an antenna, or a receiver section failing. This 
coaxial WMTS antenna design is what is considered to be 
“non-intelligent”. It is simply an active powered coaxial TV 
based diversity antenna infrastructure that is connected 
to powered telemetry receivers.

Unlike with WLAN, no software exists in a WMTS design 
to actively monitor the air space for interferers or adjust 
power for changes in WLAN signal coverage. Nor are there 
provisions for redundant failover of receivers (in case 
a receiver fails). In addition, the network management 
for a patient monitoring system operating on a WLAN 
will be absorbed into the overall network management 
costs as the patient monitoring system is operating on 
a common network infrastructure versus a proprietary 
WMTS-based system.

CoNCLuSIoNS

1. Wi-Fi is safe and reliable for patient monitoring.
2. The key to success is in the design, implementation 

and management of the network.
3. Wi-Fi opens the door to unprecedented benefits to 

the hospital, such as the ability to monitor a virtually 
unlimited number of patients house-wide, improved 
patient mobility, significant cost savings and more.

4. Wireless monitoring gives hospitals the ability to pro-
vide continuity of patient care across the enterprise 
for the entire patient stay, which is only financially 
feasible with Wi-Fi.

 ABouT THe AuTHoRS

DAvID hogLuND, President and CEO of Integra Systems, 
Inc., has more than 30 years of experience in patient  moni-
toring   networking and has authored over 20 white papers 
and publications. (www.integrasystems.org)

vINCE vARgA, Business Development Manager for Mo-
bility at Global Technology Resources, Inc. has over 13 
years of experience in wireless networking  technology,  
worked with clients across multiple vertical markets, and 
has managed more than 40 wireless LAN patient monitor 
deployments at healthcare facilities across the US since 
2004. (www.gtri.com)

www.integrasystems.org
www.gtri.com

