Wireless WAN Deployment

[tdeluz]

Looking for info on Non-Line-of-Sight Wireless WAN. Enterprise and SOHO/Residential solutions.

Already aware of the Fixed wireless Wireless WAN (http://www.thetelecomvendor.com/proxim-tsunami.htm) solutions.

Please respond to this post before sending email.

Thanks,

Tony De Luz
Solutions Consultant
TheTelecomVendor.com (http://www.thetelecomvendor.com)
tdeluz@thetelecomvendor.com

[cc1091]

Tony -
Maybe you already know this, but I think you're talking about something in the licensed spectrum and in the AM spectrum of frequencies.

I'm no expert on radio frequencies, but I think the AM band is too noisy for exchanging data for computers. Perhaps there is new technology though, and this is what you are looking for. But its hard to imagine that it would be cost effective compared to FM line of sight systems and repeaters.

[tdeluz]

That's what I figured. I've been looking into the Navini Solution and that looks the most promising, so far. I'm amazed at how slowly the second-generation of wireless networking is progressing. I would think that ubiquitious wireless broadband access would appeal to consumers and venture capitalists alike.

If you or anyone else knows of a competing solution for the Navini product, please post in reply. I'd be greatful for any insight.

Best regards,

Tony De Luz
Solutions Consultant
TheTelecomVendor.com (http://www.thetelecomvendor.com)

[cc1091]

Well I'm not sure what Navini is talking about when it says "Non-line-of-sight operation" As I understand it (and I am by no means an expert), the 802.1x unlicensed spectrum includes FM frequencies which typically fare less well than AM frequencies when it comes to penetrating into valleys and over hills. That's not to say that some signal cannot carry into those locations, its just that the datastream in those fringe areas will not have the throughput and may be subject to interference (which would cause numerous resends of the same data bit). The AM spectrum has a lot of power and can travel great distances, but it is subject to a lot of noise.

I guess there are a lot of similarities between some of the equipment used for HAM radio antennaes and the antennaes being used for transmitting 802.1x signals, so maybe I'm totally off base.

I have also heard of HAM radio operators setting up computer networks through their HAM radios. Contacting a local HAM radio club would probably yield some good basic information on the bare bones of what is required. Again, I believe HAM radio requires a license.

[barry]

You might check out a company called WaveRider they have a NLOS system that operates in the license-free spectrum. I ran across their site when checking some other information sorry, I do not know a lot about them.

Hope it helps

[ccrum]

Actually you guys have some incorrect information. 802.11 operates in only two bands 2.4 GHz(b,g) and 5.8 GHz(a). these are MUCH higher than traditional AM, FM, and HAM bands. AM falls in the 500 KHz to 1700 KHz (=1.7MHz) band. FM picks up at about 80 MHz and goes up to 107 MHz. HAM has several chunks but most are very low (some lower than AM) as well. HAM and AM have range advantages because they have very long wavelengths. The higher the freq. the shorter the wave length. The disadvantage is that because the wavelengths are so big, they don't travel well in small areas (like under bridges or inside buildings). FM wavelengths are small enough to make it into these spaces. Another simple concept is that the higher the frequency, the faster the signal attenuation. Microwave freqencies like those in which 802.11 operates attenuate very quickly not only due to their frequency, but also due to their power output limits. AM radio stations can pump out up to 50,000 watts from their transmitters. Add some gain in the antenna and you have a VERY powerful signal. WIFI on the other hand is limited to 1 watt max from the transmitter and there are limits to how much gain you can have on your antenna before having to decrease the power of the transmitter. In case you are wondering about my background, I am an RF engineer who has designed a lot of communications networks, both data and voice.

Anyway, to get back to the subject, while there are some non-los type systems out there, they are few and far between. It is a very difficult technical problem to create these systems in the unlicensed frequencies available mostly because of the limitations of the waves themselves. Radio waves in this frequency range tend to behave a lot like light. Once a signal is diffracted or reflected from a scattering object, it attenuates very rapidly. Often there is not enough energy left to make a reliable link. Licensed systems will be very expensive as will switched beam technologies like Navini's. I am guessing you want this for backhaul solutions. I would suggest using what is already available in LOS equipment and trying to find some LOS paths.