PDA

View Full Version : WiMAX Technology



Fins Left
04-22-2012, 01:15 PM
Maybe someone on here can help me.

Can an omnidirectional WiMAX transmitter be triangulated to locate its physical position?

What is a reasonable distance between transmitters for broadband back haul channels on WiMAX?

Does WiMAX challenge milimeter wave in distance (assuming you want to maintain the same through put)?

Thanks

FalconMage
04-22-2012, 02:30 PM
You need more of a radio frequency engineer than I am. I handle more the computer networking. Having said that, here's what I know:


Can an omnidirectional WiMAX transmitter be triangulated to locate its physical position?

Yes. True of any radio signal. It radiates from a source, and so can be triangulated.


What is a reasonable distance between transmitters for broadband back haul channels on WiMAX?

WiMAX was designed as a metro-wide technology. One tower *can* serve an entire city. So it depends. Number of users, bandwidth usage, and so on.


Does WiMAX challenge milimeter wave in distance (assuming you want to maintain the same through put)?

Thanks
I'm really not sure of that last. I think not. But that's outside my field of experience.

Duncan J Macdonald
04-23-2012, 10:07 PM
Maybe someone on here can help me.

Can an omnidirectional WiMAX transmitter be triangulated to locate its physical position?

What is a reasonable distance between transmitters for broadband back haul channels on WiMAX?

Does WiMAX challenge milimeter wave in distance (assuming you want to maintain the same through put)?

Thanks

1) Already answered, but yes. Any signal that can be received can be located.

2) From what I've seen in the literature, what is being done is a mix of the two -- WiMAX for the distribution to the end-user, and millimeter for the backhaul. Given that, ranges for millimeter back-haul is conservatively listed as 3 km with 1Gbps throughput. E-Band gets 5 km with 10Gbps.

3) This isn't an easy answer.

The physics of radio signals typically place two primary constrictions on spectrum. To generalize, the higher the spectrum frequency the greater the amount of bandwidth that can be transported---lower frequencies transport less bandwidth. Secondly, the lower the frequency the greater the carry range and penetration of a signal. ... The caveat that can somewhat alter this equation is power. Licensed band spectrum such as 2.5 GHz by virtue of being dedicated to one user is allotted significantly higher power levels which aids in tree and building wall penetration.

To continue, 60 GHz millimeter wave is unlicensed, 80 GHz (E-Band) is licensed.

So, the answer is --- it depends. WiMAX has less throughput (lower frequency). Millimeter Wave has less range. WiMAX has a theoretical upper bound of 75Mbps (shared among customers) while Millimeter Wave (in E-Band) can get 10Gbps (aggregated in back-haul). Using 60GHz Millimeter Wave throughput (1Gbps) as the constant, you'd need 13 1/3 WiMAX Channels to fill the 1Gbps pipe. WiMAX would have the greater range -- no challenge at all. Nominal ranges of 3 to 5 miles (4.8 to 8.0 km), better ranges under more ideal circumstances.

I do suggest www.wimax.com (http://www.wimax.com) as a resource.