IEEE antenna
and telecommunications experts address concerns over radio
frequency exposure
Citizens
in several cities including Aspen, Colo.; Bern, Switzerland; San
Diego, Calif.; and Totnes, England have been protesting the
installation of 5G wireless base stations over concerns about
the harmful effects these network nodes could have on humans,
animals, and plants. They point to the potential danger of radio
frequency (RF) radiation emitted from antennas installed in
close proximity to people.
Protestors also cite the lack of scientific evidence showing
that 5G signals, specifically those transmitting in the
millimeter wave region of the electromagnetic spectrum, are
safe. Today's mobile devices operate at frequencies below 6
gigahertz, while 5G will use frequencies from 600 megahertz and
above, including the millimeter wave bands between 30 GHz and
300 GHz.
Enough concern has been raised about 5G that some cities have
canceled or delayed the installation of the base stations.
Members of the IEEE Future Networks Initiative, which is helping
to pave the way for 5G development and deployment, took notice
of these news reports. In September, the group issued a short
paper titled
“5G Communications Systems and Radiofrequency
Exposure Limits." The report reviews existing guidelines for RF
exposure.
The Institute asked two members of the IEEE initiative about
their take on the controversy over 5G. IEEE Fellow Rod
Waterhouse is on the editorial board of the initiative's Tech
Focus publication and edited the 5G report. His research
interests include antennas, electromagnetics, and microwave
photonics engineering. He's the CTO and cofounder of Octane
Wireless in Hanover, Md.
IEEE Senior Member David Witkowski is cochair of the
initiative's Deployment Working Group. He's a wireless and
telecommunication industry expert. Witkowski is the executive
director of the Wireless Communications Initiative for Joint
Venture Silicon Valley, a nonprofit based in San Jose, Calif.,
that works to solve problems in such areas as communications,
education, and transportation.
5G PRIMER
Most of
the concerns about 5G's supposed negative impact on health stem
from its cell towers having such a different architecture than
the ones supporting today's 3G and 4G cellular networks,
Waterhouse says. Those towers are kilometers apart and placed on
tall, raised structures that are typically located away from
populated areas. Because a 5G base station can be smaller than a
backpack, it can be placed just about anywhere, such as on top
of light poles, streetlights, and rooftops. That means the
stations will be located near houses, apartment buildings,
schools, stores, parks, and farms.
“Wireless companies are going to incorporate the devices into
everyday structures, such as benches and bus stops, so they'll
be lower to the ground and closer to people," Waterhouse says.
“There also will be more of these base stations [compared with
the number of cell towers around today] because of their limited
reach. A 5G millimeter network requires cell antennas to be
located every 100 to 200 meters."
That being said, one of the benefits of these small base
stations is that they would not have to transmit as much power
as current cell towers, because the coverage areas are smaller.
“If the same amount of power that's currently transmitted from a
cell tower located 30 meters up were to be transmitted from a 5G
base station installed at a bus stop, then there would be cause
for concern," says Waterhouse, “But that will not be the case."
A 5G radio replacing a 4G radio at 750 MHz will have the same
coverage as the 4G radio, presuming no change to the antenna,
according to Witkowski. But, of course, it will provide higher
data rates and quicker network response times.
Waterhouse predicts that 5G will be rolled out in two stages.
The first, he says, would operate in bands closer to the slice
of spectrum—below 6 GHz—where 4G equipment works. “There will be
a little bit more bandwidth or faster data rates for everyone,"
he says. “Also, 5G base stations will only be in certain small
areas, not everywhere."
In the next phase, which he calls 5G Plus, there will be huge
improvement in bandwidth and data rates because there will be
more base stations and they will be using millimeter-wave
frequencies.
Witkowski says U.S. carriers that already have dense deployments
in sub-6 GHz bands will start deployment of 5G in the K/Ka band
and millimeter wave. There also will be some swapping of 3G and
4G radios for newer 5G radios.
“For the U.S. carriers that have access to vacated/re-farmed
spectrum, such as T-Mobile in 600 MHz and Sprint in 2.5 GHz,
their deployment strategy will be to leave 3G/4G alone for now,
and add 5G into these lower bands," Witkowski says.
EXISTING REGULATIONS
Waterhouse points to two international documents that have
established safe RF exposure limits. One is the guideline from
the International Commission on Non-Ionizing Radiation
Protection (ICNIRP), which has been around since 1998. The IEEE
C95.1, “IEEE Standard for Safety Levels with Respect to Human
Exposure to Electric, Magnetic, and Electromagnetic Fields" was
developed by the IEEE International Committee on Electromagnetic
Safety. and released in 2005. IEEE C95.1 covers the spectrum
between 3 kilohertz and 300 GHz. The Future Networks report goes
into detail about the various exposure limits for the body
listed in those documents.
The ICNIRP and IEEE guidelines, which are periodically revised,
were both updated this year. The limits for local exposure (for
frequencies above 6 GHz) were set even lower. Belgium, India,
Russia, and other countries have established even more
restrictive limits.
As to whether the millimeter wave bands are safe, Waterhouse
explains that because RF from cellular sites is on the
non-ionizing radiation spectrum, it's not the kind of radiation
that could damage DNA and possibly cause cancer. The only known
biological impact of RF on humans is heating tissue. Excessive
exposure to RF causes a person's entire body to overheat to
dangerous levels. Local exposure can damage skin tissue or
corneas.
“The actual impact and the depth of penetration into the human
body is less at higher frequencies," he says. “The advantage of
that is your skin won't be damaged because millimeter waves will
reflect off the skin's surface."
Waterhouse admits that although millimeter waves have been used
for many different applications—including astronomy and military
applications—the effect of their use in telecommunications is
not well understood. Waterhouse says it's up to regulatory
bodies overseeing the telecommunication companies to ensure the
safety of 5G. The general perception is that millimeter waves
are safe but should still be monitored, he says.
“The majority of the scientific community does not think there's
an issue," Waterhouse says. “However, it would be unscientific
to flat out say there are no reasons to worry."
Many opponents insist that 5G must be proven safe before
regulators allow deployments. The problem with this assertion,
according to Witkowski, is that it isn't logically possible to
prove anything with 100 percent certainty.
“Showering, cooking breakfast, commuting to work, eating in a
restaurant, being out in public—everything we do carries risk,"
he says. “Whether we're talking about 3G, 4G, or 5G, the
question of electromagnetic radiation safety (EMR) is whether
the risks are manageable. The first medical studies on possible
health effects from EMR started almost 60 years ago, and
literally thousands of studies since then reported either no
health risk or inconclusive findings. A relatively small number
of studies have claimed to find some evidence of risk, but those
studies have never been reproduced—and reproducibility is a key
factor in good science.
We should continue to look at the question of EMR health
effects, but the vast majority of evidence says there's no
reason to pause deployments."
KATHY
PRETZ - IEEE Spectrum
“5G
Communications Systems and Radiofrequency Exposure Limits."
International
Commission on Non-Ionizing Radiation Protection (ICNIRP),
“IEEE
Standard for Safety Levels with Respect to Human Exposure to
Electric, Magnetic, and Electromagnetic Fields
IEEE International Committee on Electromagnetic Safety
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