Re: WiFI on utility poles

[Mike Hammett <nanog () ics-il net>]

The tower-deployed AP can see the cable wireless APs for miles and can see a few dozen of them at any one time. Given 
the goal of full modulation at all times for optimal use of spectrum and dollars, the ever increasing noise from the 
cable APs makes this a challenge. You need 25 to 30 dB to maintain full modulation and that's increasingly difficult 
when you hear cable APs everywhere at -70. 

The APs can't have narrow radiation patterns given that they need to cover a roughly 90* area of where the customers 
are. An 18 to 20 dB gain sector antenna will pick up those cable radios from pretty far away. 




----- 
Mike Hammett 
Intelligent Computing Solutions 
http://www.ics-il.com 



Midwest Internet Exchange 
http://www.midwest-ix.com 


----- Original Message -----

From: "Scott Helms" <khelms () zcorum com> 
To: "Jared Mauch" <jared () puck nether net> 
Cc: "Mike Hammett" <nanog () ics-il net>, "Corey Petrulich" <Corey_Petrulich () cable comcast com>, "Kenneth 
Falkenstein" <Ken_Falkenstein () cable comcast com>, "NANOG mailing list" <nanog () nanog org> 
Sent: Thursday, September 10, 2015 10:00:41 AM 
Subject: Re: WiFI on utility poles 


This sounds like a hypothetical complaint, AFAIK none of the members of the CableWiFi consortium are deploying APs 
outside of their footprint. Since most of the APs use a cable modem for their backhaul it's not really feasible to be 
without at least one broadband option (the cable MSO) and be impaired by the CableWiFi APs. 


Now, there is one potential exception to this I'm aware of which is Comcast's Xfinity on Campus service, but I'd expect 
the number of colleges they're servicing that aren't already getting cable broadband service to approach zero. 


http://www.philly.com/philly/business/20150909_Comcast_streams_onto_college_campuses.html 



https://xfinityoncampus.com/login 





Having said all of that, I'd agree that a good radio resource management approach would benefit all of us, including 
the CableWiFi guys. 


http://www.cablelabs.com/wi-fi-radio-resource-management-rrm/ 







Scott Helms 
Vice President of Technology 
ZCorum 
(678) 507-5000 
-------------------------------- 
http://twitter.com/kscotthelms 
-------------------------------- 


On Thu, Sep 10, 2015 at 10:52 AM, Jared Mauch < jared () puck nether net > wrote: 



> On Sep 10, 2015, at 9:00 AM, Mike Hammett < nanog () ics-il net > wrote: 
>
> 5 GHz noise levels affecting people whose primary means of Internet access is via fixed wireless . 

This is a huge deal for those people like myself that depend on fixed wireless for access at home because there is no 
broadband available despite incentives given by cities and states and the federal government. 

The local WISPs are good at coordinating access in these ISM bands amongst themselves but when someone appears with a 
SSID without doing a peek at the spectrum (note: not a site survey, but actual spectrum view w/ waterfall, as site 
survey only checks for the channel width that the client radio is configured for, not al the 10, 15, 8, 30mhz wide 
variants). 

It’s just poor practice to show up and break something else because you can’t be bothered to notice the interference or 
noise floor you created. I suspect the hardware that Comcast is using doesn’t notice this interference or adjacent 
channel issues. With the FCC aiming to let cell carriers also clog the 5ghz ISM band it’s only going to get worse. 

- Jared