
Artemis is building a 4G network in SF to prove its pCell tech works - ghosh
https://gigaom.com/2015/02/23/artemis-is-building-a-4g-network-in-sf-to-prove-its-pcell-tech-works/
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examancer
The article asserts Artemis will need to become a MVNO. This would be a large
hurdle and one I don't think is remotely necessary. Unlimited data will make
Artemis very attractive for fixed home internet service.

Also, some small cellular networks don't offer roaming and only work in very
limited geographic areas. Many have successfully found niches among people who
don't travel much or have alternatives when they are traveling.

~~~
fragmede
I totally agree - they even mention Webpass in the linked article, though only
in passing. Webpass is an established niche ISP in San Francisco (they sell
100Mbit symmetric home internet service for $55/mo, but serve a very limited
area).

A cell-phone service that only covered San Francisco isn't worth very much to
me, but I'm sure many residents would jump at the chance to ditch Comcast for
their home internet service, and Webpass is probably just the partnership
Artemis needs - assuming the technology pans out.

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infocollector
Just started reading the whitepaper, and something does not make sense. Their
experiments are done in a controlled room with multiple antennas that are
being directed towards one pCell. That makes sense. But when this technology
goes outdoors, where the RF propagation is extremely hard to accurately
predict (especially because of the 'changing environment'), how is the pCell
created (assuming you have to have accurate location and propagation
information to create the correct interference patterns from multiple
antennas)? Something smells here.

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alimoeeny
I am not expert in this area, but I watched their presentation in NYC (or was
it Columbia U) about a year ago. The way he avoided answering any technical
questions made me think these guys are either full of shit, or they have such
a great technology that don't need to convince anybody with their world,
people will see it in action and believe them. I am now inclined to believe it
is not magic. But time will tell.

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noteloop
The 5G capabilities of the technology look amazing on paper. Hope it works out
in the real world.

Those interested in more technical details should check out the whitepaper:
[http://www.rearden.com/artemis/An-Introduction-to-pCell-
Whit...](http://www.rearden.com/artemis/An-Introduction-to-pCell-White-
Paper-150224.pdf)

Page 81 talks about pCell VR, their ideas about cloud based wireless VR tech.

~~~
MrBuddyCasino
Last time I asked there were some doubts regarding this technology (see
[https://news.ycombinator.com/item?id=7732821](https://news.ycombinator.com/item?id=7732821)).
Is the general consensus still that this is snake oil?

~~~
GeoffreyM
It's still snake oil. What they're designing is called a thinned phased array,
or sparse phased array, see figure 19 in the white paper. Such design suffers
from a major flaw known to any radar engineer: The Thinned Array curse. It
even has a wikipedia article:

[https://en.wikipedia.org/wiki/Thinned-
array_curse](https://en.wikipedia.org/wiki/Thinned-array_curse)

In layman terms, >99% of the power transmitted is lost to sidelobes and
doesn't reach the intended users (1-a/A power is lost, if you want to get
technical). Such design can carry a small number of users, operating very
close to the environment noise floor. The maximum allowed number of users is
approximately proportional to the number of transmitters. Each user added
above this limit decrease the SNR for _all_ users in the system, killing the
communication for everyone. Not a sound design for a cellular system.

Phased-array design is complex and not always intuitive. Whoever invested in
this company hasn't done proper due diligence.

~~~
kbaker
Sorry, I don't think you are correct. What they are building is not just
another phased-array system, and I don't think they are even doing any
beamforming at each transmitter at all.

Instead, they are looking at a much more difficult task, of using constructive
and destructive interference from distributed transmitters to only cohere the
signal at a single point around the receiving antenna. Think CDMA, but
spatially (like in 3d space).

> Radio frequency design and phased array design is complex and not always
> intuitive. Whoever invested in this company hasn't done proper due
> diligence.

One of the problems with what they are doing is that it is so new and flies in
the face of decades of radio theory, which as you state is already incredibly
difficult. Please give it another look, this video as well:
[https://www.youtube.com/watch?v=5bO0tjAdOIw](https://www.youtube.com/watch?v=5bO0tjAdOIw)

~~~
bravo22
I'm not agreeing or disagreeing about this being snake oil... but how do you
think phased-array and beam forming work if not by controlling phase delays
between antennas so as to create constructive and destructive interference at
a desired point, or points, in space?

Even if the air interface works the main reason I can see for carriers not
deploying this is backhaul. It would be exponentially more expensive (35x if
the air interface is indeed 35x faster) to provide bandwidth to all devices.
Right now carriers actually rely on the LTE total cap limitation to save money
on backhaul costs.

~~~
kbaker
> how do you think phased-array and beam forming work if not by controlling
> phase delays between antennas so as to create constructive and destructive
> interference at a desired point, or points, in space?

I consider DIDO separate from a phased array in that each transmitter has its
own separately transmitted signal to do the interfering, instead of one phase-
shifted copy of the signal.

Artemis/pCell is definitely not a phased array in that sense.

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chopealavu
There are no results in the white paper showing how this technology works with
moving terminals. It seems to me that if this were to be true, the
requirements on real-time processing would be incredibly humongous.

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nimrody
The real problem with this type of technology is that you'll see great
performance with a small number of subscribers.

So unless they will be able to get enough subscribers the results will still
be questionable.

~~~
ozi
But the goal of this experiment isn't to be profitable, just prove the
technology works so they can sell it. I'm sure they'll be able to entice
enough people in tech-savvy SF to buy and use one of their SIM cards for the
sake of making their case.

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DiabloD3
Screw that. Build one in my town to prove 4G exists.

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sparaker
I think this is possible.

