In 2006 the United States’ Federal Communications Commission decided to axe analog television. Analog TV, the kind of TV you received before you had cable and tweaked with rabbit-ear antennas, will go dark in 2009. Broadcasters have been transitioning to digital television, commonly known as HDTV, which requires a smaller part of the electromagnetic spectrum. (Physics primer: TV signals are just a form of electromagnetic radiation within a specified range of frequencies allocated by the FCC. High frequency electromagnetic radiation is visible as light. Read more than you could ever want to know on Wikipedia.)

Since digital TV uses less space on the EM spectrum, we can now use this extra space for something else. The FCC is holding an auction for some of this newly freed spectrum, specifically some parts of the UHF 700 MHz range. Google, among over 200 other companies, will be bidding in January for rights to these chunks (in addition to chunks available only regionally).

Most blogs and news outlets discuss Google’s imminent domination of wireless carriers. Dreams run wild of Google coming to save us from the oligopoly of oppressive mobile telephone operators. Or, some think Google might step in and be an angelic ISP, providing free or nearly free wireless access.

The sad truth is the bandwidth being auctioned is relatively limited. It’s probably not enough to operate a full fledged mobile company. It might be suitable for a wireless ISP, but perhaps at a prohibitively high cost due to the physics of the 700 MHz spectrum.

Instead, this spectrum might be most suitable for what it was used for before: television. The 700 MHz spectrum could be used as a backdoor to disrupting Comcast’s and satellite providers’ dominance of delivering video content.

Why is this spectrum not as suitable for wireless internet or mobile? Am I on acid? Would Google want to compete in the video delivery arena?

Let’s break this down.

The physics of 700 MHz

700 MHz is very well suited to broadcasting television. One tower can serve large areas. One 700 MHz tower can serve a geographic area that would require 4 or more towers when using higher frequencies (some mobile operators use 1600 MHz frequencies).

22 MHz ain’t much.

Only 22 MHz of range is available in this auction:
(Source)

What good is a 22 MHz range of 700 MHz airwaves? How does this compare to what exists?

New York City has a total available bandwidth of 183 MHz of spectrum spread across the oligopic mobile carriers AT&T (55 MHz), Verizon (65 MHz), Sprint/Nextel (43 MHz) and T-Mobile (20 MHz). (Source) Even if Google wins this auction, 22 MHz of spectrum would put it slightly above meager spectrum range of T-Mobile (at least in New York City). And, we all know how much T-Mobile sucks in service quality.

Looking at the raw numbers, this makes the idea of a Google mobile telephone network difficult to swallow. There just isn’t enough bandwidth. At the very least, Google is going to have to charge a fair amount of dough, just like those other carriers we hate, to ration the limited amount of bandwidth available. No heroic Google rescue from the high-priced oligopic carriers.

Can technology squeeze more out of limited bandwidth?

One solution is to build more towers with lower operating radii (read: lower power). Reducing the number of users per tower would increase bandwidth capacity to an acceptable level of higher bandwidth range operators. But, increasing the number of towers significantly increases costs. Yes, Google has a lot of money. But, at what point would this cost too much to implement? Google isn’t stupid. And, this smacks of further stupidity as it sidesteps one of the most compelling advantages of 700 MHz — its long range and ability to pervade walls and terrain.

There is no exact conversion from MHz of spectrum bandwidth, in this case 22 MHz, to data throughput capacity. It varies depending on carrier frequency, strength of the signal, geography, modulation system used, etc. But, it seems like 2 bits per second per Hertz of EM bandwidth is a reasonable conservative estimate for a system like this. (Source) 2 bits per second per Hertz over 22 MHz amounts to a total capacity of 44 megaBITS per second which is 5.5 megaBYTES per second.

At a max throughput of 5.5 MB/sec, Google can’t slice this very thin to offer broadband Internet. It will have to have one of these on each city block in urban areas, again, sidestepping the range capability of 700 MHz.

Here’s a better idea: move their sights from mobile operators to cable operators.

Let’s use 700 MHz for what it does best: multicasting, not individual casting.

Why go back to TV, you say? We already have digital TV (HDTV). We don’t need anything better. I think we can do better.

22 MHz of the 700 MHz band would be able to offer a comprehensive TiVo-like video on demand service.

How would this work? At 5.5 MB/sec, Google could deliver a 300MB enhanced definition (in between standard TV and true high def) episode of The Office in less than a minute. They could sell TiVo like boxes with 700 MHz receivers, a 500 GB hard drive, and basic video decoder chips with a swanky DVD-like menu interface. It would cost about $199. You ‘subscribe’ to shows you like, just like TiVo. It would also be able to pick up over-the-air digital TV from the major networks with TiVo capabilities. There would be no monthly fee for this box, it would be supported by advertising.

Continuing the math above, 24 hours of the day is enough to transmit about 1,440 30-minute programs. That’s about 10,000 30-minute programs per week. A regular TV station broadcasts 48 30-minute programs per day, or 336 per week. So, this system could broadcast the equivalent of 30 television channels. Keep in mind the actual capacity is greater since a traditional cable channel broadcasts a significant amount of repeats.

Downsides

This system would not be ideal for live broadcasting. The capability would exist, but live broadcasts would slow down the transmission of other content.

This system requires the purchase of a ‘box’. Boxes are tough to get people to buy without significant incentives. One great incentive is that there would be no more monthly cable fee. That would be incentive enough for me. This would also require Google to become a hardware manufacturer, or, at least, create a standard for others to manufacture the box. That’s a pain in the butt, but they’re starting it already with the Android.

This system requires Google to get into the business of being an on-demand content distributor. This is a messy business right now. It was hard enough for Apple to sell content for a fee on their iTunes network. It would be tough for Google to get broadcasters to sign up with an on-demand system, even if it guaranteed that commercials would not be skip-able.

Upsides

Using this bandwidth range for this purpose is MUCH MUCH cheaper to build out than building a mobile telephone network. Instead of having hundreds of base stations in an urban area, Google could serve the same area with just one or two.

Google has been trying to get in the business of TV ads for a long time. By suddenly becoming a distributor of video content they would suddenly get ownership of amazing ad inventory. And, if Google builds in 2-way communication into these boxes, they could track which ads people actually see, something that Google really likes.

When the analog TV spectrum goes dark in 2009, we’ll have to buy new digital receiver boxes to receive over-the-air TV anyway. Why not get one of the new Google boxes that combines the new HD tuner plus 30 TiVo-like premium channels for free? It would be the best time in history to convince people to get these boxes. Plus, they’d be eligible for the $40 off coupon since they’d carry a digital HDTV receiver.

Google likes to do things differently. With the limited bandwidth up for auction, it’s impossible for Google to send shock-waves through the mobile industry. But, by creatively using this bandwidth for video content delivery, Google could significantly disrupt another monopolistic incumbent: cable and satellite television.

And, who knows what this could develop into in the future? It doesn’t just have to be video content. Podcasts, radio programs, and music could all be streamed to the box for use on a mobile audio player. And, if they’re really sneaky, they could join all these ‘boxes’ together with a peer-to-peer mesh network. Want to watch an episode of The Office NOW and not wait until the next episode is pushed from the tower? Make the request and it jumps from peer to peer until it finds someone that did request to download the episode this week. 500 GB multiplied by even half the population of San Francisco — about 500,000 — is 250,000 TB. That’s a lot of collective video storage capacity.

Final thoughts: Google won’t do this. But, becoming an ISP/mobile operator will not be easy either.

I think the idea of an on-demand TV service to compete with cable operators is a cool one, but there are so many frustrating roadblocks that it would be much easier for Google to simply be an ISP/mobile operator. Google has already hinted it wants to try its hand at mobile/ISPing anyway, what with the Android announcement and all.

But, the physical bandwidth restrictions will make operating an ISP/mobile network a difficult and expensive one. If Google wants to make this an ISP-like service with current broadband speeds, it will have to put towers on nearly every city block in urban areas. This is damn expensive. Further, the FCC has strict requirements for nationwide build-out of the 2×11 MHz nationwide 700 MHz spectrum: 40 percent coverage within four years, 75 percent coverage within 10. (Source) Even if they win this auction, it’s a long road ahead for the Goog’.

DISCLAIMER: I don’t know that much about the physics of electromagnetic spectrum, especially the key figures regarding data transfer capacity given a bandwidth range. I did my best to research it (even reading articles like these), and the best I can figure out is what I wrote above. Let me know if you find better numbers.