Frequency bands for medical data transmission

Compliance & Regulatory Info Sheet Nr. 1 | Wireless Medical Devices & Connected Healthcare Applications | July 2014
A life-saving medical device needs to provide error-free data transmission and low latency, implying that the data must be available
in almost real-time. Since these are contradictory objectives it is extremely challenging to meet both goals. The result depends highly
upon the employed wireless transmission technology and the frequency band it is used in. Throughout the world a range of frequency
bands is available for transmitting medical data:
Industrial, Scientific and Medical (ISM) bands
Originally conceived for non-communication-related use of radio spectrum, the Industrial, Scientific, and Medical (ISM) bands have come to
be dominated by popular communication technologies such as WiFi,
Bluetooth, and Near Field Communication. The success of these technologies, WiFi in particular, is something to consider in the context of spectrum management strategies, especially when designing medical devices
with integrated wireless technology.
Because communication devices using the ISM bands must tolerate
interference from ISM equipment, unlicensed operations are typically
permitted to use these bands. Although the manufacturer still needs to
obtain type approval for using these bands, no licenses are required for
operating them. This makes using these bands attractive for manufacturers who want to sell in many different countries. The main disadvantage of ISM bands is that many other devices will be using the same band
at the same time.
Examples of the ISM frequencies are the 2400-2500 MHz and 57255875 MHz bands which are used for wireless LAN (802.11a,b,g), Bluetooth® or the new extremely high 60 GHz frequency band.
902 928
MHz MHz
2.4
GHZ
2.4835
GHZ
500
MHZ
125
MHZ
83,5
MHZ
26
MHZ
5.725
GHZ
5.875
GHZ
61.000
GHZ
61.500
GHZ
Frequency
The regulatory agencies in different parts of the world monitor these
bands according to different criteria. Wireless devices must comply with
the specifications of the relevant governing regulatory body. Although
the regulatory requirements do not affect the interoperability of IEEE
802.11-compliant products, the regulatory agencies do set certain criteria in the standard. It is the responsibility of the wireless device vendor to obtain product certification from the relevant regulatory body.
In the USA, the use of the ISM bands is governed by Part 18 of the FCC
rules, while Part 15 contains the rules for unlicensed communication devices, even those that use the ISM frequencies. In the USA there are also
Licence Free Part 15 bands for „Short Range Devices“ that are not ISM
bands. 315 MHz is commonly used instead of the European ISM 433 MHz,
though 315 MHz is not an ISM band.
In Europe, CE marked equipment can use the 868 MHz band lying
between GSM and UHF TV. The USA 902-928 MHz is overlapped by European 872-960 MHz Mobile bands (formerly GSM only).
Per July 2012 Japan (ARIB) has adjusted its RFID regulations by changing the country’s ultra-high frequency (UHF) range to 920 MHz. This new
spectrum closely matches that of the United States’ 915 MHz band.
RF frequencies and standards commonly used for wireless medical product design.
The selection of a specific radio-frequency (RF) standard highly depends on the product’s intended use.
Many medical device design teams adopt standards within the industrial, scientific, and medical (ISM)
bands as the basis for new products. Communication modalities in these bands include all variations of
802.11a/b/g/n, in addition to Bluetooth, ZigBee and RFID.
Wireless Medical Telemetry Services
(WMTS) bands
In response to growing concerns about electromagnetic interference (EMI)
from a variety of other licensed radio users such as emergency medical
technicians or police, the Federal Communications Commission (FCC)
has created the Wireless Medical Telemetry Service (WMTS) for remote
monitoring of a patient’s health, including devices to measure patients‘ vital
signs and other important health parameters. WMTS is approved for any biomedical emission appropriate for communications, except voice and video.
Allocated frequency bands: 608–614 MHz, 1395–1400 MHz and
1427–1432 MHz
Medical Implant Communications Service
(MICS) bands
The Medical Implant Communication Service (MICS) is an ultra-low
power, unlicensed, mobile radio service for transmitting data in support
of diagnostic or therapeutic functions associated with implanted medical
devices. In 2009, the FCC created the Medical Device Radiocommunications Service (MedRadio), incorperating the original MICS bands. MedRadio spectrum is used for diagnostic and therapeutic purposes in implanted medical devices as well as devices worn on a body (e.g. implanted
cardiac pacemakers, defibrillators or neuromuscular stimulators that help
restore sensation, mobility, and other functions to limbs and organs).
Allocated frequency bands: 401–406, 413–419, 426–432, 438–444,
and 451–457 MHz
Country-specific licensed bands
Devices using these bands are typically proprietary, implying that no interference from other users of the band can impair the system. However, the
drawback ist that operators are only allowed one quarter of the band for
one installation. Moreover, the use of these bands has not been internationally agreed to. Because of this, in addition to WMTS, many medical
device manufacturers concentrate on ISM bands such as 902-928 MHz,
and, more typically, 2.4-2.5 GHz, often using IEEE 802.11 or Bluetooth®
radios.
Standard
Frequency
Data Rate
Inductive Coupling
< 1Mhz
1-30 Kbps
<1m
Wireless Medical Telemetry
System
608-614, 1395-1400,
1427-1429.5 MHz
> 250 Kbps
30-60 m
250 Kbps
2-10 m
Medical Device Radiocommu- 401-406 MHz
nication (MICS)
Medical Micropower Networks 413-419, 426-432, 438-444,
(MMNs)
451-457 MHz
Range
<1m
Medical Body Area Networks
(MBANs)
2360-2400 MHz
10 Kbps-1 Mbps
<1m
802.11a Wi-Fi
5 GHz
54 Mbps
120 m
802.11b Wi-Fi
2.4 GHz
11 Mbps
140 m
802.11g Wi-Fi
2.4 GHz
54 Mbps
140 m
802.11n Wi-Fi
2.4 - 5 GHz
48 Mbps
250 m
802.15.1 Bluetooth Class I
2.4 GHz
3 Mbps
100 m
802.15.1 Bluetooth Class II
2.4 GHz
3 Mbps
10 m
802.15.4 (Zigbee)
868, 915 MHz, 2.4 GHz
40 Kbps, 250 Kbps 75 m
World Interoperability for
Microwave Access (WiMax)
2.4 GHz
70 Mbps (fixed),
40 Mbps (mobile)
© CETECOM Group 2014 | Contact: [email protected] | www.cetecom.com
Several
km

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