Better DIDO Explanation



By Dean ~ August 4th, 2011. Filed under: SDR & SCA.

My earlier post about Digital Input, Distributed Output (DIDO) technology was, regrettably, scant on details.  Fortunately, the MIT Technology Review just posted a great article that fills in many of the gaps.

According to their piece:

“DIDO involves intentionally combining signals from multiple transmitters, exploiting interference to create a bubble of crystal-clear reception around every user. Each signal that leaves an individual transmitter is incomprehensible until it encounters, and interferes with, other DIDO signals near a device connected to the network.

each bubble covers a small area and can occupy all the spectrum available to the network.”

Of course, I’d be remiss if I didn’t regurgitate the bit about the compute power that goes into calculating these “bubbles”:

‘Designing radio signals that will interfere with one another in just the right way takes complex mathematics and careful coordination among the different DIDO transmitters. “The computational requirements are very large, but we solved that by using a cloud server,” ‘

This is truly Extreme SDR!  Since engineers are always trained to look for holes in any new idea, I can’t help but wondering about the implications for these calculations when the mobile terminal is actually, umm, moving.  One also has to ponder the impact on backhaul bandwidth requirements when you increase over the air bandwidth by >1000x.  Will they be running multiple fiber lines to every base station?

Finally, when we consider how “real” this technology might be, we have to remember this last gotcha:

“Cell phones would require an additional radio chip to tap into such a network…”

Oops, that could be a barrier to commercial adoption, at least in the foreseeable future.


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1 Response to Better DIDO Explanation

  1. » Extreme SDR -- System Modeling Perspectives

    […] Update (2011.08.04): The MIT Technology Review just posted a great article that fills in many of the gaps left in this post.  See my follow-up post. […]