Re: 10 Mbit/s problem in your network

[Warren Bailey <wbailey () satelliteintelligencegroup com>]

If you want to see something pretty amazing, check this out..

http://www.popsci.com/science/article/2012-06/twisting-signals-vortex-researchers-beam-25-terabits-data-second

These guys got close to 100 bits/hz using Orbital Angular Momentum in addition to the normal Spin Angular Momentum. 
There is a picture out there of the I/Q showing the constellation, which to me looks like the future of communications 
systems. In my world, if you could offer 5 bits/hz or higher you would very likely be able to retire on your own 
island. Space segment for satellite systems can cost as much as 175k for 36MHz, so giving someone a 20x bandwidth 
increase would be an absolute game changer. Don't be surprised if you see the 802.11 guys trying to figure out how to 
make OAM work, it would essentially solve the worlds bandwidth problems at nearly all frequencies.

From: Owen DeLong <owen () delong com<mailto:owen () delong com>>
Date: Mon, 25 Feb 2013 08:56:05 -0800
To: User <wbailey () satelliteintelligencegroup com<mailto:wbailey () satelliteintelligencegroup com>>
Cc: Frank Bulk <frnkblk () iname com<mailto:frnkblk () iname com>>, NANOG <nanog () nanog org<mailto:nanog () nanog 
org>>
Subject: Re: 10 Mbit/s problem in your network

N has a number of advantages… Better spread, the ability to take advantage of polarization, better use of MIMO, and 
IIRC, a better encoding scheme that allows denser constellation points (more bits per signaling element).

N on 5Ghz takes advantage of the increased bandwidth of the 5Ghz channel where A merely replicated G on 5Ghz for all 
practical purposes.

Owen

On Feb 25, 2013, at 8:42 AM, Warren Bailey <wbailey () satelliteintelligencegroup com<mailto:wbailey () 
satelliteintelligencegroup com>> wrote:

I should probably know this, but doesn't N just spread better and have the ability to send receive on multiple 
polarizations? As an RF engineer I should probably know this, but I can't think of many people in my industry who 
really care about 802.11_. I really don't even use wireless in my house, though it's generally due to overcrowding the 
spectrum in populous areas.


> From my Android phone on T-Mobile. The first nationwide 4G network.



-------- Original message --------
From: Owen DeLong <owen () delong com<mailto:owen () delong com>>
Date: 02/25/2013 8:38 AM (GMT-08:00)
To: Frank Bulk <frnkblk () iname com<mailto:frnkblk () iname com>>
Cc: NANOG <nanog () nanog org<mailto:nanog () nanog org>>
Subject: Re: 10 Mbit/s problem in your network


Correct. However, while A is 5Ghz (only), it's not significantly better than G.

The true performance gains come from 5Ghz and N together. N on 2.4Ghz has
limited benefit over G. N on 5Ghz is significantly better.

Owen

On Feb 24, 2013, at 8:56 PM, "Frank Bulk" <frnkblk () iname com<mailto:frnkblk () iname com>> wrote:

> The IEEE 802.11n standards do not require 5 GHz support.  It's typical, but
> not necessary.
>
> Frank
>
> -----Original Message-----
> From: Owen DeLong [mailto:owen () delong com]
> Sent: Sunday, February 17, 2013 2:07 PM
> To: Jay Ashworth
> Cc: NANOG
> Subject: Re: 10 Mbit/s problem in your network
>
>
> On Feb 17, 2013, at 08:33 , Jay Ashworth <jra () baylink com<mailto:jra () baylink com>> wrote:
>
> > ----- Original Message -----
> > > From: "Scott Howard" <scott () doc net au<mailto:scott () doc net au>>
> >
> > > > A VPN or SSH session (which is what most hotel guests traveling for
> > > > work will do) won't cache at all well, so this is a very bad idea.
> > > > Might improve some things, but not the really important ones.
> > >
> > > The chances of the average hotel wifi user even knowing what SSH means
> > > is close to zero.
> >
> > {{citation-needed}}
> >
> > > As an aside, I was sitting in JFK airport (terminal 4) a few days ago and
> > > having a shocking time getting a good internet connection - even from my
> > > own Mifi. I fired up inSSIDer, and within a few seconds it had detected
> > > 122 AP's...
> >
> > Yup; B/G/N congestion is a real problem.  Nice that the latest generation
> > of both mifi's and cellphones all seem to do A as well, in addition to
> > current-gen business laptops (my x61 is almost 5 years old, and speaks A).
>
> I think by A you actually mean 5Ghz N. A doesn't do much better than G,
> though
> you still have the advantage of wider channels and less frequency congestion
> with other uses.
>
> Owen