
5G and Shannon’s Law - sinak
https://www.waveform.com/blogs/main/5g-and-shannons-law
======
twoodfin
The scaling of wireless bandwidth is one of the under appreciated
technological miracles of the 21st Century.

I wonder: Would even the most ambitious of telecommunications researchers in
1990 have thought it likely that in 2020 we’d be rolling out gigabit wireless
speeds to handheld devices over nation-spanning networks?

The scaling of Moore’s Law was clear by then, and certainly fiber optics
represented a practical path to near-unlimited wired bandwidth. What were the
radio folks thinking at the time?

~~~
AnthonyMouse
I still don't really get the point of 5G. It requires so many towers that
you're basically building a wired network, but then it requires billions of
dollars worth of wireless spectrum in order to get from what amounts to the
street in front of your house to inside, even though there are already phone
lines and coax going there that could be used. Even for wireless devices, that
would get you close enough to use unlicensed spectrum (WiFi) and save billions
of dollars worth of licensed spectrum.

The main benefit of cellular is when you're away from WiFi. But unless you're
constantly traveling to places without WiFi, you get that from a $20/month
plan and the existing cellular network.

~~~
karl-j
5G is not mainly for consumers like you and me. We are not willing to pay
significantly more for the faster speeds, most people are plenty happy with
4G. The big difference with the 4G to 5G transition compared to the previous
transitions is not speed, but flexibility.

5G aims to allow for completely new applications that were not possible
before, and hoping that's where the money will come from. Ultra-reliable and
low latency, and massive machine type communications are two new areas 5G is
pushing into. The first will allow applications like self driving cars, remote
control with immediate feedback, and combined with the increased speeds,
augmented and virtual reality. The second area is for the smart city/home type
of applications.

This is all from my digital communications professor with ties to Ericsson,
but on a personal note I'd be hype to explore distant places in real time by
wearing a vr headset and controlling a drone with a 360° camera and <10ms
latency. You could be anywhere in the world and actually interact with the
environment with just a 5G enabled headset and a 5G-drone renting app. Racing
through an abandoned mall! Drone laser tag in a redwood forest!

~~~
vkoskiv
> ...applications like self driving cars, remote control with immediate
> feedback, and combined with the increased speeds, augmented and virtual
> reality. The second area is for the smart city/home type of applications.

A blurb like this can be found everywhere where 5G is talked about. It sounds
technical and knowledgeable, but it actually makes zero sense whatsoever.
Self-driving cars? No. If the fundamental assumption is that every single
vehicle everywhere is communicating, that system is fundamentally flawed and
will never take off. Remote control? This has been possible for over 100
years. You can literally do that with a spark-gap transmitter, let alone
current 4G tech. Immediate feedback? In what context? Augmented and virtual
reality? Now you're just blasting buzzwords to sound smart. Come on. Smart
city/home is another common buzzword, but that's actually where the vastly
increased capacity of 5G starts to become relevant.

~~~
karl-j
Those are not my words, they're all from my professor and this [1] book,
chapter 23. With remote control and immediate feedback I'm talking about
closed loop control. Consider industrial automation with image processing done
remotely, or immediate visual or tactile feedback to human operators of remote
machinery and equipment.

[1] [https://www.amazon.com/4G-LTE-Advanced-Pro-
Road-5G/dp/012804...](https://www.amazon.com/4G-LTE-Advanced-Pro-
Road-5G/dp/0128045752)

------
owenversteeg
First of all, this is an excellent explanation of 5G that anyone moderately
technical can understand. Great article.

That said, do the numbers from the article concern anyone else at all? I'm
generally all for progress, but more than 1 million devices per km2? And
massive MIMO antenna arrays spraying EM waves in every part of the spectrum
from 600 MHz to 50 GHz?

More than a million devices per km2 ~= 3 million devices per square mile. Am I
the only one that thinks that's a bit crazy? I don't want everything from my
toaster to my door to my water bottle to be transmitting massive amounts of
information to who knows where all the time.

More concerning: the antennas. Current regular MIMO 4G towers are 2x2 or 4x4.
Already, there are 5G towers installed today that are 128x128. These are
planned to be spaced -extremely- densely in cities, and very close to people
(on every floor of offices, on lampposts, etc.) This is a necessity due to the
spectrum used. And not only that, but they're using new spectrum that hasn't
been used before - instead of the MHz to low GHz range we all know and trust,
5G towers will be up to near 50 GHz (!). Especially the fact that millimeter
wave/extremely high frequency is normally blocked by everything from drywall
to glass, but now we're intentionally aiming massive amounts of EHF waves with
hundreds of antennas in a small space.

Call me a luddite, but I'm more and more thinking that we need a high quality
longitudinal study about any effects of this kind of stuff before we go from
2x2/4x4 at well known frequencies to putting 128x128 EHF antenna arrays every
hundred feet.

~~~
GuB-42
Are you talking about health effects?

I don't have a study on hand but I expect the effect to be less than lower
frequency waves.

First thing to get out of the way, these are not ionizing radiation.
Basically, the only thing electromagnetic waves up to visible light can do is
heat. UV is borderline.

The question is what they heat. The general idea is that the lower the
wavelength, the deeper the penetration. 2/3/4G frequencies will heat your
insides, 50 GHz will only heat your skin. Of course the power is so that under
normal conditions, the heating is negligible.

As for the effect of millimeter waves, while testing this
[https://en.wikipedia.org/wiki/Active_Denial_System](https://en.wikipedia.org/wiki/Active_Denial_System)
they subjected people to massive (100kW!) doses of 95 GHz radiation. High
enough to actually burn you, and yet, the adverse effects were minimal.

If you are talking about technical problems, like interference, and how to
deal with radio waves that are starting to act a bit like light. I guess that
5G is designed by people who know what they are doing. Simply that we are able
to make it work is almost like a miracle to me.

~~~
owenversteeg
Human health would be the first thing on my mind, but there are many other
things it could have an effect on - everything from the neighborhood pigeons
to trees.

And yes, I am sure that 5G is designed by some brilliant people. Anyone
getting that close to the Shannon limit is smarter than me. My hat is off to
them.

But the reality is that this stuff just hasn't been trialed in any real way.
Sure, the US government found 600 adults to get zapped for a few hours and
only injured eight of them. But how about living with it for ten years? What
about different frequencies? 100 nm is a world away from 300nm which is a
world away from 500nm. Sure, they trialed 95 GHz and it was fine. What about
48 GHz? 25 GHz? All the other frequencies being used? What about with 256
antennae transmitting at higher power than anything before, right next to you,
day in and day out for a decade?

One big claim is that all this 5G radiation is blocked by the skin, so we'll
all be fine! Oh wait, what about babies? Turns out babies' skin is thin enough
that mm waves can penetrate the dermis...

Furthermore, ionizing radiation and heating are not the only two ways EM can
harm you. Just look at all the news about blue light for one example! EM
radiation in the mm-wave range is still far understudied compared to the cm
wave range.

Look, I think that 5G is probably going to be fine, health wise. But for
something as big as this, it absolutely deserves at least one good
longitudinal study. Of which there have been zero.

~~~
mhh__
The EM spectrums are already nearly full - is that not proof in itself?

On top of that the military uses absolutely enormous energies in their RADARs
and there's still little if any evidence of risk even including powers where
you might as well have you head in a microwave oven

~~~
owenversteeg
>> The EM spectrums are already nearly full - is that not proof in itself?

... What? I have no idea what "full" would be, but by any definition they are
certainly not. Just a bit of air is enough to attenuate mm waves of even high
power. (That's why we need so many towers!) There is not a lot of ionizing
radiation out there, that's why we're not all dead (and why x-ray film even
works.)

Maybe you're thinking of outer space? But it's not even true there - for an
obvious example, visible light, which there is very little of by human
standards pretty much everywhere in the universe.

"The military used it for some time and nobody died so let's put it pointing
everywhere in our homes and offices" strikes me as a very weak argument for
something's safety. As just a simple counterexample for why you cannot use
that to demonstrate safety, consider that while mmwaves do not penetrate the
adult human dermis, babies' skin is thinner and is easily penetrated by
mmwaves.

~~~
mhh__
The electromagnetic spectrum is in use pretty much everywhere someone can
build a radio to operate on that frequency.

> "The military used it for some time and nobody died so let's put it pointing
> everywhere in our homes and offices"

[https://en.wikipedia.org/wiki/RAF_Fylingdales](https://en.wikipedia.org/wiki/RAF_Fylingdales)

This is a 2.5MW Phased Array. If there was any provable health risks to these
(there are ~10 of them in the west) we would know - there have been
suspicions, but they have been investigated and no evidence has been found.

Why do we care about microwaves in particular when there are huge
installations like these operating at much longer wavelengths which as you say
penetrate further?

If there was immediate danger from electromagnetic radiation it would have
been observed years ago - powerful microwave emitters have been in use in very
proximity to humans since the second world war (Randall and Boot developed
their magnetron in 1940)

I have quite a few of the papers that 5G nuts cite, and they are not
convincing in this slightest - there is not a single paper that is both
dealing with radiation within FCC limits, on animal test subjects, and have
any macroscopic threat to health. This also doesn't include the issue that
these papers are usually reports of fairly limited research so there is no
discussion of the relative risk of their findings if there are any at all
(Historical Evidence as mentioned previously sets an upper bound on that risk
too).

~~~
owenversteeg
>> The electromagnetic spectrum is in use pretty much everywhere someone can
build a radio to operate on that frequency.

Well, first of all, "the electromagentic spectrum" is "in use" everywhere in
the universe, and includes things like radios and the sun. What I think you
meant to imply is that humans have been living with mm-waves before for
extended periods of time. Which is absolutely false. The problem is that mm-
waves are attenuated by air, or clothing, or buildings, or the atmosphere, or
what have you. There are some mm-wave sources that humans have messed around
with, but always for short durations (usually on the order of hours/days) and
nearly always with a strongly attenuated signal (air, cars, buildings in the
way.)

The reality is that no group of humans have ever lived their normal lives with
a mm-wave source, period. The closest you can get is police speed guns, the
vast majority of which are in the 10-25 mW range at 10-35 GHz. They are
pointed away from the user; either you're the cop aiming them at someone, or
you're the person in the car being tracked (if you're in the car, 35 GHz won't
penetrate.) Even if you're a cop that decided to just point the radar gun at
your face 40hr/week for ten years, that's far, far less exposure than someone
living in a city equipped with 5G.

So nobody's lived their lives with a mm-wave source, OK. In order for mm-waves
to ever actually get -to- your body, you would have to propose a new massively
expensive system deploying massive amounts of unprecedented power mm-wave
radios closer to humans than ever before: in other words, 5G.

>>
[https://en.wikipedia.org/wiki/RAF_Fylingdales](https://en.wikipedia.org/wiki/RAF_Fylingdales)
(and the rest of your comment)

Come on, that's completely different from what we're talking about here -
that's a centimeter wave system. Humans have lived with the presence of
centimeter waves for a while, and we are fairly sure they're safe. Cell
phones, microwave ovens, RC cars, everything uses centimeter waves.

>> I have quite a few of the papers that 5G nuts cite, and they are not
convincing in this slightest

Well, I'd like to point out I'm not a 5G nut. I typically don't bother
clicking on those weird rabbit holes of conspiracy blogs tied together with
red string based on some inconclusive data. I'm also not saying 5G is
dangerous. I simply believe it's unknown. We simply do not know, as a species,
what living our lives bombarded with unprecedented amounts of mm-waves will
do, as nobody has done it before. Likely it will be harmless; however, there
is a chance it will not be. As with many things, it may be the cumulative dose
over many years that is harmful.

~~~
mhh__
> Well, I'd like to point out I'm not a 5G nut

I wasn't accusing you. They're usually well-meaning rather than overly
conspiratorial - although there are a few near me who, let's just say don't
mention the Rothschild family near them.

In line with your final paragraph I suppose I agree that we don't know for
sure, but it's unlikely.

As to high frequency radio waves specifically, Fighter aircraft have had
millimetre band radars which people have worked with for half a century at
least now (along with microwave links in the cities and satellite links etc.).

I feel like it's important to point out that long term exposure can't be too
long term in the sense that the phenomenon has to be weak enough to have not
yet been observed yet strong enough to outpace the churning of biological
material in effects.

As a final remark, here is some actual data about 5G exposure in relation to
local limits (UK in this case) i.e. fractions of a percent of the ICNIRP
guidelines at most. Also, no one I'm aware of has proposed a mechanism as to
why the wavelength matters at this scale?

[https://www.ofcom.org.uk/__data/assets/pdf_file/0015/190005/...](https://www.ofcom.org.uk/__data/assets/pdf_file/0015/190005/emf-
test-summary.pdf)

------
sumanthvepa
One thing to note is that the frequency bands specified only apply to US 5G.
Huawei's 5G spectrum uses a much lower frequencies: Around 3.8GHz. This falls
in the mid-range spectrum, which makes it cheaper to deploy, because the waves
travel further and you need fewer towers. That is the attraction of Huawei,
for most countries (outside of the US).

Ref: [https://www.huawei.com/en/about-huawei/public-
policy/5g-spec...](https://www.huawei.com/en/about-huawei/public-
policy/5g-spectrum#:~:text=Sub%2D8GHz%20frequency%20band%20for,primary%20bands%20in%20specific%20countries).

EDIT: Fixed typos.

~~~
o-__-o
Also interferes with a lot of hospital devices that operate in that freq
range. It’s a fight I am casually observing from the sidelines with popcorn.

~~~
jessaustin
Wifi has been around a long time now. Why can't the hospital devices just use
that like everyone else? (Oh except wireless microphones in churches, which
are also some special snowflake exceptions for some reason...)

~~~
chongli
Because everything interferes with WiFi. It’s junk spectrum. You don’t want
critical, lifesaving devices operating on the same spectrum as the microwave
in the break room.

~~~
jessaustin
"Critical, lifesaving" functionality is for the most part hardwired. Some
devices use radio over extremely short range (think arm's length), but any
radio communications over longer distances are for reporting or something else
non-critical.

------
barryaustin
Excellent article - still I can't resist a rather large quibble.

The commonly stated assertion that spectrum is a limited resource is not quite
accurate.

Spectrum is technically defined as a range of frequencies. That's all. In
business parlance spectrum is also attached to large areas of land - this
spatial dimension is more important than most people realize.

Radio signals themselves exist in space and time, not just in a range of
frequencies. More radio signals - and data bandwidth - can be packed into a
given space by shrinking the volume a given signal "occupies".

We can do this by reducing signal power and increasing cell density, in
addition to other techniques described in the article. More cells, smaller
cells. This is a big part of how 5G expands cell network capacity. But the
telecoms have downplayed the effect of this relative to the the claim that
spectrum is limited.

The mobile carriers have financial incentives to do this. These incentives are
lower costs and monopoly control. Fewer bigger cells at higher power are
cheaper than many smaller cells at lower power. The monopoly part is exclusive
use of spectrum on a given piece of land.

The problem is, the legal attachment of spectrum works with very large areas
of land (where km^2 is a smallish unit) and large periods of time (years),
relative to radio signals. Both attachments are grossly inefficient.

By shrinking cell size (power) and increasing cell density, several orders of
magnitude more network bandwidth is possible, plenty even to share (modulo
cost of physical infrastructure).

Spectrum scarcity is a myth. The current legal regime enriches monopolists and
is otherwise a tremendous waste of potential. We pay higher prices for
unnecessarily limited bandwidth.

~~~
mNovak
Spectrum scarcity is also a function of our wasteful utilization.

What you describe (small cells) is one version of what we call spatial
multiplexing. Basically, reuse spectrum in physically separate areas. But you
can also do this in a way that doesn't sacrifice the centralized, large cell
architecture.

Namely via beamforming. You don't have to share spectrum if you're not dumping
power in all directions. Already cell towers are split into three sectors; you
could continue to increase sectors, or dynamically point beams at individual
users. Being suitably isolated from one another, each beam allows spectrum
reuse.

It's not free obviously, it requires more expensive base station antennas, but
I think a direction we'll be heading in.

------
fyfy18
Would anyone like to speculate on what new tech we will see that will take
advantage of this? I can already stream (to my device) a 4K 60fps video while
in a park, and at home I have gigabit fiber (up and down) which is barely ever
used to it's full potential. What cool stuff will I be able to do in 10 years
time when I have 10Gbps upload while sitting in a park?

~~~
Nursie
You'll be able to ditch the home fibre connection.

You'll have lower energy use modes available for battery powered IoT devices.

You'll be able to be in a very dense crowd and have your services still work.

It is also lower latency that 4G, so things like gaming over your 5G
connection become more possible.

These may not matter to you, but they are use-cases that 5G allows.

~~~
ghaff
It's not clear to me that it makes sense to replace wired with wireless when
density is such that fibre can be economically laid to a location.

5G has a lot of possibilities both for improved mobile data and for last mile
where it either doesn't exist or is some old 1Mbit ADSL line. But I'm not
convinced it will generally make sense to ditch good wired broadband just
because 5G is available.

Even if you technically could, I expect the economics won't work out, e.g.
throttling/caps/overage charges, for people trying to do a lot of data-heavy
things like video streaming if they have an alternative.

------
lmilcin
Actually, low range of high frequency signal is beneficial. The reason is,
that even at relatively large transmission power the signal dissipates quite
quickly meaning you can have stations service relatively small area.

This means the spectrum is shared by less users, the uplink is shared by less
users, you can serve higher concentration of people.

------
jessaustin
No mention of unlicensed bands? After the demonstrated superior utilization of
those tiny portions of this range allocated for ISM? My goodness, it's almost
as if FCC works only to perpetuate outdated "giant telco" models to the
detriment of all consumers!

Out here in the country we'll operate our own "small cells" without permission
from ATTVZN and without paying FCC a cent. If anyone notices there will be
"investigations" but mostly no one will notice because physics. Eventually
industrial users of this tech will realize "hey we don't need those telco
goofballs either!" and their lobbyists will muscle through some exceptions.
Eventually everyone whose house has sheetrock walls will be so excepted.

~~~
ac29
This article wasn't about unlicensed/ISM radio, though there have certainly
been advances there as well. I'm genuinely curious about which parts of the
ISM range you see with "superior" utilization compared to cellular networks -
I work with those type of radios for a living.

~~~
jessaustin
For most of the spectrum, the devices and services that consumers may purchase
are limited to those available from giant hierarchical oligopolies. In the ISM
bands, we have a bunch of different technologies, but most importantly Wifi.
There are much less stringent barriers to anyone using or selling devices and
services that use Wifi. And it all works! Those who live in dense urban areas
sometimes scoff at Wifi, but what they're seeing is the tiny segments of
spectrum allocated to unlicensed use, not inherent problems with open
spectrum. The excuse offered in the past for spectrum oligopolies was "oh it's
physics" because the very simplest radio technology we could imagine in the
1930s does suffer from interference at lower frequencies. Of course we've had
more advanced radio tech for a long time, but ignore that... at the
frequencies under discussion for 5G, interference over any but the shortest
range is no longer a threat. That means that most of the claimed justification
for telecom monopolies (and perhaps the agency created to enforce those
monopolies) goes away. It's sad that TFA is still focused on "carriers".

~~~
ac29
Sure, I dont want to understate the impact that WiFi has - its a good
technology, and its great that it can be used without a license. I wish more
spectrum was available unlicensed - a portion of my income depends on it! My
unlicensed radio experience is largely with 900MHz ISM systems, and I wish
"its just physics" was a lame excuse. Fact is, the #1 thing limiting
performance on these systems in most urban and suburban places is noise - I've
installed plenty of radios capable of high order QAM that were limited to QPSK
or even GMSK strictly due to noise. I'd say the noise floor in 900MHz ISM is
something like 3-5 orders of magnitude higher than in similar sub-GHz licensed
systems. Uncoordinated frequency hopping systems are noise-resistant, but
still leave a lot of theoretical performance on the table.

Cellular systems have their purpose too - WiFi is not a good technology for
covering a city with internet access, as many attempts to do so should prove.
Nor would it be wise to allow unlicensed use at high power - ask anyone who's
ever lived in an apartment how their WiFi is, then imagine if power levels
could be increased by an order of magnitude to or two.

------
k__
_" 5G towers won’t be “towers” – instead, they’ll be “small cells,” mini-cell
sites mounted to light poles that cover just a small area"_

I had the hope, 5G would finally solve the coverage problems in rural areas.
sounds like it's just a vanity project after all...

------
badrabbit
[https://www.gaia.com/article/5g-health-risks-the-war-
between...](https://www.gaia.com/article/5g-health-risks-the-war-between-
technology-and-human-beings)

We should not listen to scientists about 5g health concerns?

5g highband is basically an always on radio that can pinpoint specific users.
Like,you would be tracked as you move room to room and interact with people.
Why is everyone ok with this? Especially when hardware killswitches are not
the norm or legally required.

------
ksec
Just a note.

Massive MIMO is not a 5G only thing. 3GPP Rel 13 on 4G already had it for FDD-
LTE. And for TD-LTE it was supported from Released 8 or 10 if I remember
correctly. Massive MIMO in 5G only meant NR was designed with it in mind.
Although mostly in the sense of TDD still, FDD Massive MIMO still has some on
going work to do.

But yes, in many case 5G is more like 4.99G. It is pretty much a evolutionary
step from 4G Rather than a big leap from 3G to 4G. And we should expect
capacity to increase from 5x to 10x.

------
donclark
How does Starlink fit into this scenario?

------
AtomicOrbital
if anything 5G will put extreme pressure on more efficient computational
paradigms to replace our half century old silicon approach ... biology evolved
the human brain to run on 40 watts of power ... the massive additional carbon
footprint of 5G will accelerate our escape from silicon

------
baybal2
Multipath MIMO can effectively beat both Shannon, and Nyquist through
utilising multiple spatial channels.

------
m000z0rz
Warning, this page does the annoying chatbot thing, but with the addition of
sound notifications.

~~~
ehsankia
I thought the one lesson we all learned from Clippy is that this kind of
interruption is more annoying than useful, I guess the new generation of
developers have never experienced Clippy?

Also why would I need help when _reading a blog post_??

~~~
anonymousab
>I thought the one lesson we all learned from Clippy is that this kind of
interruption is more annoying than useful

It's not about usefulness, not really. It's about engagement and retention -
much like newsletter spam and annoying please-subscribe popups, The Metrics
always apparently show that they work amazingly compared to a clean page.

~~~
metaphor
Oh yes, _hand-waving_ "The Metrics". What do they say about how often and the
speed in which reader view was enabled?

------
cinquemb
> there are theoretical limits for each medium.

I would rather say that there will always be limits of our understanding and
building equipment for usage in various mediums, even in a vacuum, we're still
only probing our theoretical knowledge of null boundary interactions between
photons[0].

> For example, a standard cellphone can fit an array of 72 antennas operating
> on the 39 GHz mmWave band. A similar 72 antenna array in the 700 MHz low-
> band frequency would be larger than a typical home door.

And what would it cost? In an environment where cellphone sales have been
declining for at least 5 years now at least on the high end (all the games
Apple has been playing with sales reporting…), which end users will be willing
to bear the cost of the device now?

[0]
[https://www.youtube.com/watch?v=bH7OGkEZX7I](https://www.youtube.com/watch?v=bH7OGkEZX7I)

