
10 gigabit Ethernet 80 GHz point-to-point bridges - walrus01
http://www.elva-1.com/products/a40106
======
wrigby
It's interesting to see the huge channel bandwidths they're using to attain
this. Advances like this are largely driven by higher sample rate ADCs and
DACs becoming more viable in recent years.

Edit for clarity: channel bandwidths in the datasheet are up to 2 GHz. Need to
close the link at 32 QAM to hit 10 gb before error correction overhead at that
bandwidth, which is certainly doable. Also, it's interesting to note that they
quote 7 gbps throughput @ 1 GHz bandwidth, and 10 gbps at 2 GHz. It implies
that they can run at 256 QAM at 1 GHz, but only 32 QAM at 2 GHz, which also
makes sense.

Having worked in the satellite communications industry, where channel sizes
used to be limited to 72 MHz (because of hardware limitations of the
spacecraft), getting modems designed to operate on larger channels is no small
task. I would love to learn more about the internal architecture of these
radios to understand exactly what's going on - are they using interleaved
ADCs? Is the modulation/demodulation being done in an FPGA, or an ASIC?

If there are terrestrial microwave engineers on here, I'd love to hear your
thoughts on this!

~~~
e2phd
You can pack many bits into a constellation point. Think 1024 QAM.

~~~
walrus01
Most new licensed band 6, 11, 18, 23 GHz radios these days are 1024QAM
capable. For 80 GHz the hot new thing is radios capable of 16/64/256QAM at
varying code rates.

~~~
Dwolb
What's the limiting factor when designing to a constellation? Otherwise,
what's improved about the chip or firmware to be able to move from 256QAM to
512QAM?

~~~
walrus01
signal/noise ratio is a big one and RSL level. There are even 4096QAM radios
now but they need a signal like -51 to operate at their full modulation.
Otherwise they ACM down to 1024 (around -62), 256 and then 64QAM.

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mey
• Secure communication due inability to intercept the laser-like beam
transmission at free air

I would not trust that as a security layer.

~~~
walrus01
It's definitely not something to trust in, but intercepting (at a layer 1
level) a PTP 80 GHz link is actually harder than tapping fiber. You'd have to
have Rx equipment either directly in the path or directly behind both ends of
the radio link.

As compared to the effort required to cut an aerial or underground singlemode
cable and fusion splice in place a passive prism split tap (basically the same
thing as inserting a split in a GPON FTTH network). A practiced outside plant
fiber crew of 2 persons and a bucket truck could do this with less than 5
minutes of downtime on a router-to-router optical interface, short enough time
to clear any NMS alerts and prevent a repair team truck roll. Assuming we're
talking about only two strands.

Either way actual security is accomplished through standard based crypto, not
obfuscation or preventing people from messing with the layer-1.

~~~
omgtehlion
On a fiber you don't need downtime at all. If you manage to carefully clean
the fiber from isolation and buffer and then bend it just enough to leak some
light into yours.

So, assume that everything might be tapped and encrypt your data.

~~~
walrus01
Yes, or if your fast, cheap new metro ethernet 10GbE circuit between two
buildings has been provisioned by your ISP as some form of transport (handoff
into a WDM system, EoMPLS tunnel), etc, it's not difficult for them to
'mirror' your port. It could be pre-tapped before it was ever turned up for
customer service.

Or the splitter could be installed in your riser cable at one end, before you
ever started moving packets across it.

Or a myriad of other things.

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nixisfun
This would get really bad rain fade at 80GHz or even on a humid day the speed
would back off a lot. You need to run a lower frequency backup link in
parallel.

~~~
walrus01
That's the nature of 80 GHz, design the links for your climate and don't try
to go more than 2-3km. You can achieve five nines. And yes, run a 5.x GHz
backup path in parallel.

~~~
kardos
> You can achieve five nines.

As long as nobody pilots a drone in the path.

~~~
walrus01
It'd have to be a big ass drone, I have links that stayed up when a Canada
goose was sitting 2 ft directly in front of the 60cm antenna on one end.

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ChuckMcM
Crap, now I need to go buy a couple of these and lobby the nearest data center
for some rooftop space.

That is the short way of saying I had no idea you could get antenna this
effective for wireless data transmission. I'd seen the 5mbps ones but nothing
close to a gigabit much less 10 gigabits. Time to draw a 10km radius circle
around my home address :-)

~~~
tlrobinson
I've seen up to about 400 Mbps on my Webpass [1] connection for a couple
years, and I think that's pretty run-of-mill tech at this point [2]

1\. [https://webpass.net/](https://webpass.net/)

2\. [https://www.ubnt.com/broadband/](https://www.ubnt.com/broadband/)

~~~
walrus01
Webpass uses a fairly large number of Siklu 80 GHz 1 Gbps radios on rooftops
for backbone links in SF.

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alex_h
What kind of licensing (FCC or otherwise) would one need to operate such a
radio bridge in the US? or is it public spectrum?

~~~
walrus01
80 GHz is "light licensed" in the US, the paperwork requirements are not
onerous. It's less costly and complicated than a regular part 101 licensed
microwave link.

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jessaustin
The word "Ethernet" in the title is misleading. That word does not appear in
TFA, which appears to discuss a radio transceiver.

[EDIT:] I stand corrected; thanks!

~~~
walrus01
It has a 10GbE SFP+ optical interface and functions as a layer 2 ethernet
bridge. From an ethernet port perspective same as 99% of the other PTP
microwave and millimeter wave radios on the market. What's new is the 10Gb (vs
existing radios with 1Gb SFP).

Read the datasheet linked at the bottom of the page.

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ArnoldP
I have line of sight to the building where I work, I would love something like
this so I could get gigabit internet at home w/o paying through the nose :)

~~~
mikeyouse
Check out Mimosa's offerings.. For a few hundred dollars you can get ~750mbps
via unlicensed spectrum up to ~5km distance.

[https://www.mimosa.co/Products/Backhaul/backhaul-
specs/B5-Li...](https://www.mimosa.co/Products/Backhaul/backhaul-
specs/B5-Lite-Specifications.html)

I know Ubiquti has similar products as well but I'm more familiar with
Mimosa's.

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walrus01
it's worth noting that this is just the first one publicly announced and not
under NDA.. It's from a russian radar/microwave/millimeter wave manufacturer.
All of the other much larger players such as Bridgewave also have 10 Gbps
radios coming.

~~~
madengr
Those BW 80 GHz links are pricy$$$, but like anything the cost will come down
in a few years.

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vessenes
Ooh, I really want two of these. I'm stuck on an island with poor last mile
service providers. But, I have line of sight to a number of spots with good
quality fiber.

~~~
Havoc
If you've got line of sight then current (cheap) tech should do just fine.
Sure not 10x gigabit but you can def get some decent internet...

~~~
adrianpike
Do you have any recommendations for current products for line of sight?

~~~
mcpherrinm
I know some people who have successfully used Ubiquiti's airFiber for point-
to-point links. I think those run on the order of $5 grand for a complete
installation (two radios, mounts, etc) of a faster-than-gigabit link.

~~~
marcusr
We run some between offices across the street from each other. We were lucky
as we didn't understand the minimum distance was probably more important than
the maximum distance for this type of setup! They have run flawlessly at about
800Mbps for the last year.

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martinald
Interesting.

There has been a huge effort in the UK for mobile carriers to add fiber to as
many cell towers as possible.

Do people think this would undo this trend? I'm sure that 10gbit would be more
than enough to carry the backhaul of 3G+4G with plenty of room to spare?

~~~
walrus01
not really, fiber is still greatly preferred (For example: it's impossible to
do 40Gb by microwave/millimeter wave, but a CWDM 4-channel 4x10GbE passive
mux/demux on two strands of singlemode is trivial and very very cheap), or
just a pair of 40Gb QSFP 10km reach optics using a single 1550nm wavelength
between two routers or metro-E switches. But wireless can reach small cells,
rooftops and towers that might be a very costly underground fiber build at
$400-900/meter total construction cost to dig up streets in urban cores. It
very much depends on the location.

~~~
amazon_not
Plus there's the reliability factor. With fiber you only have to worry about
backhoe fade. Wireless has all kinds of fun failure modes.

~~~
walrus01
Though with small monopole and cellular rooftop sites, MW can frequently be
built in a ring or redundant traffic path configuration. Fiber to many
endpoint sites like a cell tower is frequently a star topology network with
one cable in a linear path along a ROW either aerial or underground.

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punnerud
What is the price for this?

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mlakkadshaw
Do these products require a clear line of sight to work?

~~~
amazon_not
Yes.

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zurn
According to Nielsen's law of bandwidth, consumer gigabit last mile should be
common by now and 10G would be a logical next step development, becoming
ubiquitous in 2020 or so.

There's a huge number of houses with idle fiber installed 10+ years ago.
Gigabit ethernet was introduced 17 years ago and carries 5 km over fiber.
Cable is just waiting for providers to switch on 10 Gbps since years ago.
Phone line copper has similar story..

Maybe something like this could jump-start the stalled development of last-
mile consumer internet.

~~~
revelation
You can put the savings into better bandwidth for consumers or lower cost for
ISPs. With no competitive pressure for the former in the majority of the
country, providers have happily pocketed the 3+ order of magnitude
improvements while providing the same old 1990 speed.

~~~
amazon_not
Some of those savings are needed in order to be able to provide 100M/1G to the
consumer: \- 10G in the distribution \- 100G in the core

So, even with competitive pressure, consumers can't expect to receive the
latest and greatest for peanuts.

------
imauld
And here I am with 12MbS down/800KbS up

