On Saturday 06 December 2008 10:15:20 Johannes Berg wrote:
> Yes, well, depending on which values you used you might have run into
> the fact that the values from the tables were already rounded.
Both errors happen for 20 Mhz channels... one of them is definitely a typo in
the wiki.
I get 144.4 MBit/s (wiki says 144.0) for MCS 15 (long GI)
and 115.6 MBit/s (wiki says 173.3, which is a typo !) for MCS 27(short GI).
in pseudocode:
-----------------
int modulation = mcs & 7;
int streams = mcs / 8;
int bitrate = (flags & 40MHZ) ? 13500000 : 6500000;
if (modulation < 4)
bitrate *= (modulation + 1);
else if (modulation == 4)
bitrate *= (modulation + 2);
else
bitrate *= (modulation + 3);
bitrate *= streams;
if (flags & SHORT_GI)
bitrate = (bitrate * 10) / 9;
return (bitrate + 50000) / 100000; // do NOT just round down
Henning
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