How Many Wireless Technologies Can We Handle?

Golygydd Max writes "The space for high-speed wireless networking is getting mighty crowded. Techworld reports that a new company, Sibeam, has entered the fray, hinting at a 60GHz technology to compete with the likes of Wimax, UWB and the others. Does the world really need another player when the future is still so unclear?"

Comments

Agreed

[cryptochrome]

The analog dials go up into the 60s, but you're lucky if you can pick up more than five or six stations most places, and most people have cable or satellite anyway. Most of it's going to waste. Open the bandwidth to the public and let TV networks set up video on demand instead. I mean look at this thing: it's unspeakably crowded. Public channels are tiny slivers, yet they're the hottest use of spectrum around. Surely this could be simplified and opened dramatically.

Of course, when the government can just sell public spectrum at a tidy profit for its own needs, what do you expect.

Radio is pretty crowded though, I wouldn't mess with it. Really though, if there were advertising-supported free digital/satellite radio we wouldn't need that either! But of course, AM/FM radios are tiny, simple, cheap things these days, and there are a ton of them. Until digital receivers are more common in cars it's foolish to think of replacing them.

Re:60Ghz!!!

[imsabbel]

You are basically right.

At the very high frequency edge of the electromagnetic spectrum, photons start to get through matter more easily again.

But the stress is on _very_ _high_.

We are talking about GHz here. The worst penetration power is somewhere in the UV. Up to that it still declines, and further way to high energy it increases. (simply because how the photons interact with matter. With higher energy they start to directly excite molecule rotations, then vibrations or phonons in solid bodies...

So you can say: go from optical down to lower frequency, and stuff gets better "around the corner" (non-line of sight) and gets better penetration, but getting higher also gives better penetration.

But for wireless, you are still 4 orders of magnitudes to low in frequency to get there.

Re:60Ghz!!!

[greed]

That's due to losses in a conductive medium, known as the "skin depth effect". Longer waves have a deeper skin depth, so are carried deeper into a conductor. (Salt water is approximately a conductor.)

In the opposite direction, very high frequencies use only the surface of a conductor. Consequently, microwaves aren't run on wires, but are actually sent down hollow "wave guides". If you need any sort of power, you'd need a massively thick wire, but the energy will just be on the outer surface. So we use a tube, the waves don't care.

Tesla coils use this effect for rather dramatic results.

Re:None?

[zippthorne]

"Type Acceptance" In order to get type acceptance (basically a license for the radio) It must meet specific FCC regulations, one of which is that it must not be capable of transmitting out of band or at unallowed power levels.

Amateurs are licensed operators and so equipment designed for their use need not be type-accepted: the operator is expected to obey FCC regs rather than the device.

I don't think the company would be liable if someone modified their equipment to transmit out of band or at higher power or whatever, but if it turned out to be very easy to remove the blocks, their devices' license would probably be revoked and at the very least, much greater scrutiny would be applied to products from that company in the future.

I also don't know what the penalty is for selling equipment that bascically can't be legally used, but I imagine consumer groups would have a field day with that.

Re:standardize

[default luser]

I can see them starting with 802.11b and then going to 802.11g, only to realize that it'll drop down to 802.11b speeds for all connections when one 802.11b client is allowed to connect...

802.11 doesn't work that way.

Every time an 802.11 device sends a packet, it includes a preamble sent at 1 Mbit. The preamble indicates the speed the rest of the packet will be sent at. Thus, the network can support each client sending at different data rates.

A single 802.11b connection will not significantly reduce the speed available to other 802.11g users (it just takes a little more airtime for the 802.11b user to send data, and thus reduces the maximum possible speed slightly). However, each 802.11b user you add to an 802.11g access point means each transmission to and from them takes longer...and that means more chance of collision than with the same number of 802.11g clients. So yes, a well-mixed crowd of 802.11b and 802.11g clients will run at near 802.11b speeds.

The simple solution? Don't let access points get saturated in the first place.

I too am interested in what 3 technologies a university would switch to. I suppose there is Boingo but other than that, 802.11 is the only thing that would make sense today. UWB tomorrow maybe but who knows?

You're forgetting that, before 802.11b, there was 802.11 (1 or 2Mbit data rates). There is also 802.11a, as well as other proprietary standards.