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Showing posts from September, 2014

What's New (and Missing) in the WiFi for iPhone 6

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Two years ago tomorrow Apple introduced the iPhone 5.  It was a big deal.  It was a big deal for gadget folks who wanted a bigger iPhone.  It was a big deal for wireless LAN folks who wanted users to use smartphones with speedier WiFi.  

Now the iPhone 6 has been announced and it appears to be more of the same.  Gadgeteers get their bigger iPhone.  Wireless folks get their faster speeds.  Problem is, the faster wireless speeds likely won't mean anything for high capacity wireless deployments.

The big news about the iPhone 6 is 802.11ac.  Yippee!  Apple has finally adopted the latest and greatest WiFi standard in a mobile device.

802.11ac has data rates as high as 6.9 Gbps in the standard, but wireless LAN folks know that's not what happens in real life.  Real 802.11ac devices top out at a 1.3 Gbps data rate when multiple input-multiple output (MIMO) antenna systems are supported, while non-MIMO devices top out at 433 Mbps.

The iPhone 6 and iPhone 6 Plus are non-MIMO 802.11ac d…

Capacity or Coverage or Neither?

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In the beginning, there was Coverage.  And so it was that 802.11 and his only begotten Son, WiFi were blessed upon PCMCIA cards who doth receiveth adequateth Coverage.

And then as Coverage grew and the lands of Tablets wereth discovered, so came Capacity.  And thus did Capacity grow to represent all that was good and great about deploymenteths upon this fruitful land.

And now, my Sons and Daughters, things have changeth again.   For Coverage and Capacity will both leave the Higheth of Densiteth WiFi wanting.  And so we shun them both.  For it is Neither -- Coverage nor Capacity -- that will taketh thy to the WiFi promised land.

In case it was unclear, designing wireless LANs for Capacity has become an article of faith in some circles.  Keep it to 40 devices per AP.  Or 50.  Or 150.  Whatever the number is, the whole concept is misguided.

WiFi uses radio frequency as its physical layer, and there is a finite amount of radio frequency in any given location.  If every radio frequency chan…