Slashdot Mirror
FCC Set To Finalize Rules For Next-Gen Wireless
GovTechGuy writes "The FCC's agenda for Thursday includes a vote on the final rules for unlicensed devices making use of unused TV spectrum known as 'white spaces.' Industry and lawmakers have predicted the opening up of the white spaces could result in the biggest leaps forward in wireless technology in the past 25 years. Among the benefits is so-called 'WiFi on Steroids' which allows a large number of users within a 50-mile radius to tap into a single high-speed broadband connection for the same price as a traditional WiFi router. The FCC is expected to approve the move, but Google and other companies warn that the devil is in the technical details of the rules."
>>>(600 megahertz is a frequency, not a bandwidth.
How on earth did you get out of college with an engineering or science degree?!?!? The SI unit "megahertz" can be applied to a discrete point (600 million cycles per second on the EM spectrum) - or - as a measure of bandwidth (700 through 1300 MHz == 600 megahertz of space). So going back to what I said:
- Cellphones have been assigned, by the FCC, approximately 600 megahertz of bandwidth
- TV has been assigned approximately 200 megahertz of bandwidth
Perhaps I am to blame. Perhaps I wrote my sentence in shorthand (aka technospeak) but this IS slashdot after all - I expect technically-minded persons to understand the basics they learned in PHY101.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
The spectra weren't even used by analog broadcast TV. The spectra consist of unused space between the old channels, space that was left unused to avoid interference, harmonics, etc. between the analog channels.
Be relentless!
So if the data doesn't fit your assumptions, you just cut it in half? Nice.
Methodology for the Trenton, NJ area:
By posting this, I'm un-modding some other stuff. So be it.
With CB, you have to listen to everyone else's banter. Communications are broadcast, by definition, to anyone else whose particular squelch setting and receiver sensitivity will allow them to receive it. It is easy for one party in one conversation to step all over another party in a completely different conversation, while being completely unaware of it.
There are no PL tones on CB to limit unintentional interference and distractions, just different channels.
But I hasten to say that things have moved on:
We now live in a world where communications are neither so rude, nor so limited.
It is now trivial to determine the precise sender and recipient of a transmission (hello, IP). It is trivial to ratchet down output power, automatically, such as to very nearly speak only to those who you intend to speak to. And it's possible to share a band, due to things like CDMA, TDMA, and OFDM.
None of this exists on CB.
And when mesh networking enters the picture, things become even less like a CB.
The acceptance of a white-space provision by the FCC, no matter what modern technology it consists of, will be a boon for communications amongst a populace -- including the torrenters and the porn mavens, as well as the web browsers and the Facebookers.
To think otherwise is to disregard everything, so far, that the Internet has brought to us, as well as everything that has been learned about RF communication over the past few decades.
Kid-proof tablet..
This is going to work really well... not
Think about it. Compare this mythical 50-mi radius super WiFi to an existing hotspot. Or cell tower, for that matter...
1 - Contention. how many clients will be in that coverage footprint, competing for the bandwidth. Radio is a shared medium - only one source can be using it at a time (disregarding exotic and expensive tricks). So you split it up into channels - there goes your bandwidth. And you MIMO the area into sectors - bummer if you live on a sector boundary and bounce between them. No matter what you do, you have to divide a limited resource among a whole lot of users. Suddenly, small local cells look a lot better.
2 - Power. Sure, your local TV station gets great coverage (or since digital, not so much). They've got a 50-Gazillion-Watt transmitter, and it's one-way. How much power will your laptop/tablet/phone/etc. need to talk reliably to a base station 50 *miles* away? At a decent data rate, with the interference of everybody *else* trying to get the attention of that base? It's hard enough to do on analog *voice* systems. If you thought hidden-node problems were bad with WiFi, you ain't seen nothing yet! Oh, and how big are the antennas going to have to be for these lower frequencies (compared to 2.4Ghz)? The next iPad will have a band around *it* for the antenna....
3 - Infrastructure. How many of these mega-APs will get to be in a given area? Does everybody get one (hey - no license)? It's not going to be easy or cheap to backhaul all of those clients from your huge central site. It's simple to serve a small area at a time, and the cell companies certainly have the hand-off issues worked out (well, mostly). But the only long-range two-way systems out there are fairly low-bandwidth and server relatively few nodes.
You can have bandwidth, coverage, or population - pick 2.