CPUC approves first subsidy for Internet via TV white space

19 January 2016 by Steve Blum
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White space below the tree line.

Besides allowing a wireless claim jumper to ace two towns out of fiber to the home service last Thursday, the California Public Utilities Commission approved a $1.1 million grant from the California Advanced Services Fund (CASF) for wireless Internet service in northern Eldorado County. Cal.net’s deployment is the first CASF project to lean heavily on newly available television white space spectrum.

The plan is to use a combination of three bands: unlicensed 5 GHz, LTE in semi-licensed 3.65 GHz spectrum and coordinated TV white space, with three usage cases, i.e. line of sight, near line of sight and non line of sight, respectively. If they engineer it correctly, white space facilities would be used for backfill; 5GHz and 3.65 GHz support much higher throughputs.

White space will play a bigger role in serving two small, heavily forested communities – Garden Valley and Greenwood – according to CPUC documents. It’s not clear if white space will be the only solution deployed there, or if it’ll just be particularly necessary.

If you draw a big circle around Garden Valley, there’s about 400 homes (using, as I do, egregiously round numbers). A 50% take rate (Cal.net’s near term projection) gets you 200 subscribers. At 30 Mbps per channel and assuming a max package of 10 Mbps down/3 Mbps up (as the fine print says, higher speeds require specific equipment and signal strength, and may not be available in all areas) one white space channel gets you a 100-times oversubscription rate, two channels bring it down to the 50-times range, and so the worst case scenario goes.

But draw a tighter circle and/or assume that 5 GHz or 3.65 GHz will be installed to reach at least some homes, and the case enters the plausible range.

Cal.net’s budget (grant plus private capital) comes out to $1,200 per home in the service area, including middle mile backhaul via licensed spectrum and a fiber tie-in. That should be enough to pay for professional engineering and a robust buildout. Even so, pricing and max speeds – from $70 per month for 6 Mbps down/2 Mbps up, to $160 for 25/4 where available – will perpetuate rural California’s digital divide, rather than end it, as the CASF program is intended to do.