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802.16 WiMax Wireless Broadband on the Horizon
"The IEEE 802.16e spec, which will support mobile applications, is expected to be complete by early 2005. Nextel, Sprint and BellSouth are all interested in the technology to deploy services like streaming video and TV, wireless phones, and high-speed Internet service in unserved, low-density areas near high-density ones. Mobile operators in developing countries like Brazil's NEOTEC group have already successfully tested an 802.16 wireless broadband deployment. Intel communications group executive VP and GM, Sean Maloney, is banking on it. From the article: 'We believe that WiMax can happen, and be widely deployed, and be a big deal in the next three years the same way Wi-Fi has been a big deal the last two years.' Mirrors at Network World Fusion, Techworld and PCWorld. What happens when techies start to build their own 802.16x WiMax VoIP systems?"
No, higher bandwidth means higher bandwidth - i.e. the range of frequencies used for transmission of information is wider. The frequency used is irrelevant from the point of view of capacity. A 0-100MHz channel has the same capacity as a 1GHz-1.1GHz channel. Of course physical transmission varies widely at different frequencies, as you point out, but there's no fundamental relationship between capacity and frequency.
If I seem short sighted, it is because I stand on the shoulders of midgets
Usually, higher bandwith means higher frequency. Higher frequemcy means less range, since the waves is easilier interupted by obstacles, like trees. and so on. Someone care to explain this to me?
Without getting too technical - you're right, sort of. The article is rather muddled; it mentions the frequencies in question (2.5GHz region, which is microwave), and then has some confused sentence about "point-to-multipoint meaning no line-of-sight is necessary". Well, that's nonsense. Microwave propogation is almost exclusively line-of-sight. Without LOS, signal strength drops off dramatically.
However, if you use spread-spectrum techniques (which 802.16 does), you can overcome a lot of these problems. Basically, the characteristics of a wideband SS signal are such that multiple reflections (even weak ones) can be separately received and combined. This is a big gain over narrowband radio, where reflections cause inter-symbol interference which causes the signal to deteriorate.
Another factor that may be more significant - this standard seems mainly to be for delivering broadband to fixed installations (not mobile stations). Well that's an easier job by orders of magnitude: you only have to site the antennas correctly once, and you never have to worry about them moving around.
In conclusion: it's quite different from the radio technology we're most used to, and there's a little thing called progress to factor in too! :)
Hope that helps.
These sigs are more interesting tha
Not to mention I can easily Guess that the transcivers are not for deregulated bands aswell. With a ~50K Range It would be nearly impossible to make it available for home use. Even if the Range was cut down to a mere 3K (Aprox 2 Miles) Spectrum congestion would make it unusable.
Who needs WiFi when we can have Packet Over Sheep! http://datacomm.org/PoS-InternetDraft.txt
please refrain from posting.
. htm
Spectral efficiency measures the ability of a wireless system to deliver information within a given amount of radio spectrum and is directly related to system capacity. It determines the amount of radio spectrum required to provide a given service (e.g., 10 kbps voice service, 100 kbps data service) and the number of base stations required to deliver that service to end users. In the latter years of deployment, when subscriber penetration is high, it becomes one of the primary determinants of system economics.
Spectral Efficiency = Channel Throughput/Channel Bandwidth
Spectral efficiency is measured in units of bits/second/Hertz/cell (b/s/Hz/cell). It determines the total throughput each base station (cell or sector) can support in a network in a given amount of spectrum.
Copied from: http://www.arraycomm.com/pcct/spectral_efficiency
There's a million places I could point you to. So to say that capacity and frequency are not related is simply wrong, if not ignorant. The same definition stands for all wireless communications schemes, regardless of whether they use cells or not. All operators, whether it's Telephony or Networking deploy their networks and offer services based on spectral efficiency and power needed to achieve that efficiency. Nothing else. Bit rates, Frequency and all the rest of it are just byproducts...
/. Where the truth
This will be using licensed frequency blocks, and won't interfer with the 2.4GHz unlicensed frequences used by 802.11.
All this really is, is warmed over MMDS. MMDS was going to be the next big thing in the 90's - Sprint, in particular, was active in MMDS (you might remember it was called Sprint ION). As with a lot of new technologies, it was rolled out into a few markets, lost a lot of money, and was shut down.
Flash forward a couple of years - 802.11b/g (WiFi) is hot (hence the name - WiMax), broadband Internet usage popular, and the equipment is better/cheaper, so wireless companies are going to give it another go - except this time it will be sold as broadband Internet + VOIP, instead of a replacement for cable TV and also broadband Internet.
From browsing the user reports in the DSL Reports forum, it looks like, despite Sprint's best efforts to feck it up, most people really were happy with their ION performance, and very sad to see it shut off.
Using a decent wireless solution is the only IP backbone most places I have been have had. Microwave mostly, some spread spectrum stuff. 100mbit backbone would be amazing in a lot of poorer places. Sure, cable would be better, but significantly more expensive. A lot of governments don't care about mid to long term, because nobody plans that way when they themselves don't intend to be there too much longer. They might lay cables in road development works and when distributing electricity, but to cover massive distances cheaply, wireless is the way to go.
Oh, and I've lived and worked in Africa. Tunisia, Morocco, Malawi, Niger... and in the Caribbean in Haiti too. I made the mistake of making a short post earlier, perhaps, but you are so wrong here. Have YOU been to Africa? Have YOU worked in telecoms in Africa? I have.
Conversion Rate Optimisation French / English consultant
I've got five moderator points this morning and there is exactly one post in here I'd mod up - the guy who suggested that people not post if they don't know anything, but he already has a +5.
There is a link in my sig to my journal and there you'll find a brief description of how 802.11 (wireless lan) and 802.16 (wireless access) differ.
50km == 30 miles. I've installed 2400MHz and 5800MHz links on the same 22 mile path and I've done a bunch of other 20 +/- 2 mile shots using 5800MHz.
At 22 miles with 19dB dishes on each end we saw analog modem speeds with 2400MHz (802.11b) equipment. Using 29dB 2' Andrew dishes and 100mw 5800MHz radios we saw a solid 5+ mbits on a radio that maxed out at 8 mbits.
I've planned a 40km 45 mbit shot for a project that didn't go through - I think we had a 4' dish on the remote tower and a 6' dish on the skyscraper end of the link.
Whatever band and modulation method they're using in these breathy 802.16 announcements the physics aren't going to be much different than what I describe above - long shots are point to point, cells are small (3km - 4km) if you want to go fast, and I mentally say "snake oil" when I hear the letters O-F-D-M. It works, but it ain't "all that", as they say.
So, mod me wise, or mod me troll, but know this: The slashdot collective has as much business talking about wireless networking as any room full of male gynecologists and cross dressers has talking about childbirth.
I am very easy to get along with, but I don't have time to waste being nice to people who are being stupid. -Theo
Actually, Sprint's MMDS offering was (is) called Sprint Wireless Broadband Direct. While they are not going after new customers, this service is still available in a few cities to existing customers. Sprint ION was more of a DSL/ATM/Voice combo. As far as I know, it had nothing to do with wireless service.
You can use spatial diversity (which is similar to cranking down the power, really), frequency diversity, and polarization diversity to prevent interference. If you choose frequency-agile user equipment, you could deploy many hotspots covering a particular area and use signal strength to choose which to use (a la cell phones). Similarly, using polarized antennas can lead to significantly less interference (rhcp vs lhcp, not just horiz vs vertical).
For instance: Using fairly directional antennas, aim RHCP signals north on even GHz every few blocks across lower Manhattan, and LHCP signals every few blocks pointing west on odd GHz down the west side. Form a grid of access using both freq and polarization diversity. Naturally you could alternate sites east/west, north/south so reception would be equalized around the island.
Good luck!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
er, probably not. The 2.4GHz, the FCC has a 4-watt EIRP limit on point-to-multipoint links, and I can't think of a reason that they would allow more power on these devices. Since a 2.4GHz link can go 30+ miles, 4 watts seems reasonably low.
It takes ~90 seconds for a 1000 watt microware to warm a glass of water, and quite a bit longer to actually boil it. 4-watts is minimal, and since RF power drops off at the inverse square, at 10' it's practically in the mW range. You'd have trouble even *warming* water that was right next to the antenna.
Now, point-to-point links can be ~150 watts. That would probably warm water to 100 degrees, given enough time, but antennas of that magnitude are ~4 degree beamwidth (you can't run power like that through an omni), so you'd literally need to stand right in front of the apex of the dish.
I'm more concerned about the 200mW Senao 802.11 card in my laptop irradiating my crotch, thank you very much.