Community Wireless Summit

Posted by Sam Churchill on

I was chatting with some friends from the Personal Telco Project the other day. PersonalTelco has done some amazing and innovative community networking projects using inexpensive WiFi equipment.

PTP president Russell Senior had just returned from a conference in Barcelona about community wireless.

Apparently the idea of meshed community WiFi networks is not dead (yet). Meshed networks relay signals from adjoining nodes. They extend the range of a signal.

But when you’re talking about WiFi, the range is rarely more than a few hundred feet.

Non-profit groups like PersonalTelco and Seattle Wireless, as well as commercial mesh network companies like Tropos and SkyPilot tried to make community WiFi networks fly. They failed when the required node density made it too expensive, costing up to $100K per sq mile. Commercial 4G was cheaper and more reliable.

Among other things, the noise floor of WiFi – soon jammed with hundreds of nodes every mile – made connecting to a WiFi node a block away a real challenge.

After a couple of beers I blurted out, “What PersonalTelco needs is an App”.

It was a joke.

But I soldiered on, explaining that “white spaces” are the new thing. Soon phones would support the 600 MHz band – using unused tv channels for licensed – and maybe unlicensed – broadband wireless.

I opined that a single white space antenna on a TV tower might cover the entire community.

Since bandwidth would be limited, “the app” might feature text-based “talk channels” with a twitter-like interface and small pictures. Land Mobile Radio (LMR), for police and fire, don’t need more than a few radio towers in the 450-800 MHz bands.

Homeland Security might pay for half, with matching funds from local interests.

It was an amusing idea.

But hey. The 470-512 MHz T-band is scheduled for reallocation in 9 or 10 years from now. It was a last minute compromise in order to get the broadband “D-Block” allocated to public service.

According to, the consensus thinking among public safety’s leaders is that giving up the T-Band in order to get the D Block was a very small price to pay.

Both LTE-A and WiMax 2.0 can use the licensed 450-470 band for broadband wireless, squeezing everything into a single, 5 MHz channel. The specs are ready. The radios will be ready, soon.

WiMax 2.0 (802.16m) is designed to operate in a variety of frequency bands including 450-470 MHz and 698-960 MHz.

If 802.16m can support 60 active users per 1 Mhz, then a 5 MHz channel on the 470-512 MHz band might support 300 users per 5 MHz sector. A re-farmed 470-512 MHz band might work for public works or local public safety communications. It can travel dozens of miles.

Some 20 UHF channels (120 MHz), from TV channels 31 though 51 will be vacated for broadband wireless. The FCC ought to require unpaired (TD-LTE) on those channels.

Ownership of that prime spectrum by the big four wireless carriers ought to be capped at 20 MHz each, (80 MHz total). The remaining 40 MHz would be available for smaller carriers as “lightly licensed”, or as unlicensed White Space.

That’s competition.

Even if a similar unlicensed “white space” transmitter only delivered a practical range of 3-5 miles, that’s pretty useful. It could save lives in a natural disaster.

It’s a blank canvas for DIY networking.

It’s in everyone’s best interest to preserve some of that unused television space. Selling unused TV spectrum to television group owners and big telecom monopolies will put it behind a pay wall.

If the new spectrum is unlicensed and available to the public, we all benefit.

Wi-Fi is unlicensed. It created an economic boom. White Spaces are no different.

Posted by Sam Churchill on Friday, October 26th, 2012 at 2:14 pm .

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