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Harry
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WLAN Toolbox: A-MPDU length is wrong for 802.11ac (VHT) packets?

Asked by Harry
on 6 Oct 2017
Latest activity Commented on by Harry
on 12 Aug 2018 at 20:43

I am using Matlab 2017a with the WLAN Toolbox. As far as I can see, there is a bug in that the MPDU length is set incorrectly in the A-MPDU delimiter for 802.11ac (VHT) packets.

In R2017a/toolbox/wlan/wlanexamples/vhtWaveformGeneratePSDU.m there is a function named "delimiter" which sets this field. However, it basically does a direct de2bi(n,14) conversion to binary, which (as far as I can tell) fails to properly handle the two "MPDU Length High" bits described in the 802.11ac standard (see Figure Figure 8-505a1 in Section 8.6.1).

Has anyone else seen this? Or can anyone confirm whether this is a bug or not?

Many thanks!

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1 Answer

Answer by GAURAV PUROHIT on 12 Aug 2018 at 5:29

i agree can you share your mail id for more discussion

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I don't see any need to message privately. Anything we discuss may help someone else, so it makes sense for it to be visible on the forum.

I contacted Mathworks and they have confirmed that this is a bug. They were actually very responsive and also confirmed a couple of other bugs I found (and provided fixes very quickly). Hopefully, these fixes will eventually find their way into future releases of the WLAN toolbox. However, the last time I checked, I couldn't see any of the fixes available for download in isolation yet.

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