Steve Jobs' Near/Far WiFi Problem, Explained (Video)

Steve Jobs introduced the iPhone 4 yesterday. You may have heard about this snazzy little device and you may have also heard about the problems Mr. Jobs had in demonstrating it. Mr. Jobs blamed the problem on WiFi, and as best I can tell he was right. I whipped up a quick video to explain what likely happened.


It's my first video blog post, so be gentle. Thanks to Rough & Tumble Films in Los Angeles for providing the space and Nick Robinson (@nickrob on Twitter) for helping me out with the shoot.




Comments

  1. Mark DavisJune 10, 2010 at 2:23 AM

    hi Ben,

    I enjoyed your explanation of the Wi-Fi problem on Steve Jobs recent iPhone release. However, I think the problem was more likely due to excessive numbers of 802.11 management frames being transmitted. I doubt if there were 300 or so Wi-Fi hot spots (i.e. Mi-Fi devices) present in the auditorium, I suspect there were 300 STAs busily transmitting probe request frames to a few APs in order to gain network access. Typically, an un-associated STA will transmit a few probe requests frames a second and if you then multiply this by several hundred client STAs trying to do the same thing, then you have a very busy wireless medium and more importantly the collision probability will be high, probably so high as to render any form of reliable communication almost impossible. Furthermore, even if you did manage to become successfully associated with an AP, the capacity available will be so small that it will probably cause any http or tcp/ip session to time out.

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  2. Ben MillerJune 10, 2010 at 11:26 AM

    I have to disagree. The Apple Airport client in OS X, and the Windows clients for XP SP3, Vista and 7 all disable Probe Requests after a station is associated.

    It is possible that management frames could have been a problem due to excessive Beacons, but that would go back to the problem of having too many APs on one channel.

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  3. Quique EspañaJuly 22, 2010 at 2:59 AM

    Interesting approach as for the issue understanding, considering that most or all of the APs could've been in the same power output range; as for the solution, fewer APs or one AP per channel is an obvious solution but in Job's case, I think they could've been one step ahead and consider your visitors\attendees would bring their own APs, so, Job's people should've set up an AP with stronger signal, by simply attaching a stronger antenna (i.e. 5dbi) because, stronger antenna = stronger signal = better reception = steadier connections, but maybe they just didn't see it coming....

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