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  • For those who love abbreviations, the Wi-Fi Alliance (WFA) has defined a new figure of merit for Wi-Fi.

    Actually, it's a little more convoluted than that. In coordination with the CTIA, the WFA has defined FRR for Converged Wireless Group (CWG) Wi-Fi devices - i.e. cellphones. It is an addtional performance requirement for all new cellphones.

    It is fully described in the "CTIA / WFA CWG RF Test Plan".

    FRR stands for Frame Reception Rate, and is the phone industry equivalent of our own Packet Error Rate (PER).

    Mathematically, FRR and PER are ALMOST complements of the other. If you're measuring PER in Percent, then FRR (%) = 100 ? PER(%) and PER(%) = 100 ? FRR(%).

    Or, put another way, FRR (%) = (# of ACK?s received / # data Frames transmitted) * 100, and
    PER (%) = (1 - (# of ACK?s received / # data Frames transmitted) ) * 100.

    So if you're measuring sensitivity at a PER of 10% for an 802.11g device, that would roughly equate to the sensitivity at an FRR of 90%.

    EXCEPT, that for FRR measurements the test packets are only 200 bytes long (versus 1024) and are sent at a rate of 50 frames a second "...to approximate a voice data stream." So it's not quite the same thing!

    They have also modified how Power Measurements are taken. The CWG only measures the power levels of the ACK frames, not the data.

    On the one test I got a chance to run so far, the FRR Sensitivity showed a one percent better result than the PER test. But I'll test it some more in the future, and let you know the results.

    If you interested into looking into this further, search the Anritsu, and ETS-Lindgren websites and search on CWG, CTIA, or WFA.

  • Here's another entry for the dictionary: [b]dBr[/b]

    The official dictionary has all sorts of dB this and dB that, but not this one.

    You'll often see it in relation to 802.11 Spectrum Masks. Here's one, from the spec, for 802.11g:

    "I.2.3 Transmit spectrum mask

    For operation using 20 MHz channel spacing, the transmitted spectrum shall have a 0 dBr (decibel relative
    to the maximum spectral density of the signal) bandwidth not exceeding 18 MHz, ?20 dBr at 11 MHz
    frequency offset, ?28 dBr at 20 MHz frequency offset, and ?40 dBr at 30 MHz frequency offset and above."

  • It's been a while since I've suggested any new words, but here is one that I think is good enough for the industry, as a whole, to start using.

    It doesn't show up in any of the 100 M of IEEE files that I have, but it probably should.

    The entry ? [b] LSTA[/b]

    "Any legacy STA device that does [b]not[/b] support 802.11 [b]n[/b]" .

    Of course the alternative claim could be made that everything will be "n", so why bother - well, for the same reason the WEP WLAN's still exist.

  • By (Deleted User)

    The problem with such a term (i.e. LSTA) is that its reference is constantly evolving. In 2007, an LSTA would have been 802.11b. In 2009, 802.11g. In 2013, 802.11n. And so on. :)

  • Yeah. I know :(

    Maybe not a good candidate for the book, but in some contexts it might help.

    I hadn't thought of it before, but similar to IEEE (2007) we could use LSTA (2007), or even LIEEE 802.11(2007).

    Reductio ad absurdum

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