
Bell Labs Researcher Discusses the Realities of 5G - ChrisGammell
https://theamphour.com/430-shahriar-discusses-5g/
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leoh
It's hard for me to understand why anyone is excited about 5G when most
carriers aren't running full bandwidth 4G and have significant data caps.
Although 5G may be fast in some markets, 5G on the whole just seems so
pointless for consumers.

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jjoonathan
If new bandwidth / more bandwidth means new market entrants / more market
entrants, it'll be great!

I am sure that legions of lobbyists, politicians, and businessmen are working
diligently as we speak to make sure that doesn't happen, but I want to
believe.

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rayiner
Notwithstanding this supposed lobbying, we have four nationwide 4G
networks—more competition than we have in putatively lobbying free markets
like social media, search engines, and cell phone and tablet operating
systems. The biggest roadblock to 5G is not lobbyists, but rather NIMBYs
complaining about how small cells will clutter up the neighborhood.

~~~
jjoonathan
...and one cable internet provider at nearly any given location.

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superkuh
Great interview. At the start Dave kind of conflates 5G with millimeter wave
5G.

The big difference between LTE networks and 5G networks is not the frequency
ranges used, low band 5G is perfectly feasible. The big difference is the
linear increase in information capacity per antenna in MIMO (multiple in
multiple out, many send many receive antenna) verses the logarithmic increase
per antenna with single antenna to single antenna links. (while power his held
constant)

If you want to learn more this is a great intro to channel capacity with MIMO,
[http://complextoreal.com/wp-
content/uploads/2013/01/mimo.pdf](http://complextoreal.com/wp-
content/uploads/2013/01/mimo.pdf)

~~~
freyir
Just to be clear, MIMO is not a new feature in 5G. LTE has MIMO. Old Wi-Fi
routers from 10 years ago had MIMO.

5G is upping the number of antennas per base station. Theoretically, this
allows a linear increase in capacity, but linear scaling is not always
achievable in practice.

The advantage of the higher frequency bands is the larger bandwidths available
there. Conventional cellular bands typically have 5, 10, or 20 MHz bandwidth,
sometimes 100 MHz. 5G's millimeter-wave bands support bandwidths up to 400
MHz. Information rate scales linearly with bandwidth. That said, there are
many practical challenges to operating in the millimeter wave bands that might
limit real-world performance.

~~~
ksec
>MIMO is not a new feature in 5G

Or Specifically Massive-MIMO, which is as you said upping the Antennas per
base Station. LTE Massive MIMO actually already works in 3GPP Rel 13 for FDD,
and Rel 7/ 8 for TDD. However 5G were specially designed with M-MIMO in mind,
which brings higher efficiency than using in on LTE.

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nimish
4G->5G is the equivalent to upgrading from gigabit to 10 gigabit ethernet yet
everyone is treating it like some kind of insane technology.

I have yet to see what exactly the hype is about.

~~~
johnm1019
I mostly agree but I want to nitpick.

One of the areas I've heard should be improving with 5G is latency. On 4G
we're talking O(10ms)? which on 5G, so says the marketing, should be O(1ms).
If this is true, it will make a noticeable impact on the responsiveness of web
driven apps (aka almost all apps) as well as video/audio chat liveness. Was
this oversold to me (highly probable)?

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dharma1
Reducing latency between the tower and your phone by 9ms won't make a big
difference to the overall experience of web apps. But I think real world 4G
latency is more like 40-50ms?

In addition to mobile network latency you have to add a few more things -
depending on how far you are from the data centre serving the web app you're
looking at ~20ms-300ms additional network latency, plus however long the
server takes to process your request, regardless of 4G or 5G. Check out
[https://www.cloudping.info/](https://www.cloudping.info/) for some ping times
to AWS datacentres around the world

~~~
johnm1019
FYI O(10ms) means anything from 10-99ms.

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edoo
If you've ever seriously played with wifi tech you very well know the higher
the frequency the less penetration you get. In an indoor environment the
difference between 800Mhz and 2.7Ghz can be astounding. 5G at 90Ghz is only
going to work at certain line of sight distances. If you ever hear anyone
talking about terahertz speeds you can almost be guaranteed that would be
happening with very specifically located devices or within the confines of an
integrated circuit.

~~~
Spooky23
In my city, they are dropping poles with 5G radios all over the place, as
close as every 150-300 yards. It’s a land rush as the city cannot do anything
to stop them, the poles get dropped in all sorts of awkward places. My
understanding is that repeaters will be mounted on streetlights as well.

Those radios aren’t for phones, they are for fixed wireless with antennas
attached to your home. 5G is the cable killer, and eventually the WiFi killer.

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chrisco255
What city is this and why can't the city do anything to stop them?

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Spooky23
Albany, NY.

The FCC is choosing to let the telecoms do whatever. It’s wasteful as they do
things like block crosswalks with additional poles (to avoid renting from the
electric utility) and place the poles in less attractive spots to reduce cost.

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post_break
What I don't understand is if we get faster speeds, will we still see data
buckets stay the same? I mean what's the point of a faster network if you're
still capped at 2,5,10GB. And will qualcomm be the only game in town thanks to
patents? My iPhone Xs feels like a bicycle in terms of data speed, while my
Galaxy S8 is 2-3 times faster.

~~~
tzs
> I mean what's the point of a faster network if you're still capped at
> 2,5,10GB.

For those (a large majority, I suspect) whose actual data usage is determine
by factors that have little to do with the network, the point of a faster
network is less time waiting.

For example, I'm going to take about the same number of photos on my phone if
I'm on a fast network as I will if I'm on a slow network. The fast network,
though, will mean less waiting to transfer the photos to my desktop for
editing or for sharing.

A good way to see this is to go the other way. Suppose you have a 10 GB cap.
Would you object if your network were slowed down to dial-up modem speed (56
kb/sec)? That's more than enough to transfer 10 GB/month, so what's the point
of anything faster if you have a 10 GB cap?

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kylec
I get what you're saying, but the faster your connection speed is the easier
it is to inadvertently use more data. With my carrier if you hit the monthly
limit they throttle you to 128Kbps, which is basically unusable. However, they
offer a plan that's capped to 3Mbps all the time, which is fast enough for
virtually everything I need and makes it much harder to hit the monthly data
cap.

I actually prefer always getting 3Mbps any time I want to use my phone
compared to the more expensive plan which might get 30-50Mbps... until you hit
your cap and you're throttled to 128Kbps. (But, as you'd imagine, if I'm A-OK
with 3Mbps, I have a hard time seeing what benefit 5G brings me.)

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kirrent
This is a great interview! I have to say, learning about the requirement for
multiple antenna modules in a smartphone, each with impressive phased arrays,
the massive investment that's going to be required in microcells, and the
myriad of other engineering issues to be overcome, properly put in context how
ludicrous AT&T's badging of 4G technologies as 5Ge is.

[https://arstechnica.com/information-
technology/2019/01/att-d...](https://arstechnica.com/information-
technology/2019/01/att-defends-misleading-5g-network-icons-on-4g-phones/)

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freyir
Every 5 years or so, there is a rally to make millimeter-wave communications a
thing. Every time it fails. Maybe there's enough money and effort his time
around to make it happen, but I wouldn't bet on it myself.

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PunksATawnyFill
That’s just a bunch of bullet points. LAME.

