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hello to every 1...a thing that is confusing me that

1) is there any relationship b/w ofdm and line of sight? mean if we use OFDM than do we need line if sight...plzz put some light on it?


i took this q's from given lines below that i read on some website


"BreezeMAX is Alvarion's award-winning WiMAX platform designed from the ground up according to the IEEE 802.16 standards and uses OFDM technology for advanced non-line-of-sight (NLOS) functionality. Since its launch in mid-2004, BreezeMAX has been successfully deployed in over 180 installations in more than 80 countries around the world".

I'm not going to say I'm an RF Engineer (because I'm not) but I think that this is marketing mumbo jumbo.

LoS depends on frequency and I don't believe that modulation would have a lot to do with it. Could someone confirm/deny?

http://en.wikipedia.org/wiki/NLOS

NLOS has some truth under the right conditions. Albeit not something you want to promise your customer.

What I think they are taking advantage of is the spectral enhancements to OFDM over the last few years ( there are many new variants). This gives the appearance of a radio with some sort of remediation for the reflections and refractions associated with objects along the RF path. This touted with throughput is increased over a longer distance, makes it appealing to say NLOS.

Moreover as with MIMO, they are deploying smarter antennas with beamsteering platforms to make this NLOS more of reality.

The need for (Fresnel Zone) clearance is still there.

http://www.fab-corp.com/pages.php?pageid=2

The difference is the range and distance of the enhance OFDM signals are the derivatives of having more TX power available with of course higher gain directional antennas giving it certain NLOS marketing strategies.

I believe that their adverts maybe slightly skewed. IMO the real enhancement is using MIMO which is developed very heavily in 802.16. OFDM is the best suited modulation scheme for use with MIMO as is mentioned in this Intel link.

http://www.intel.com/technology/itj/2004/volume08issue03/art05_multiantenna/p02_intro.htm