seemoo-lab / nexmon_csi

Channel State Information Extraction on Various Broadcom Wi-Fi Chips
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Incorrect Amplitude in CSI Data from ASUS Router #320

Open Guolin-Yin opened 1 year ago

Guolin-Yin commented 1 year ago

Hello everyone,

I've been using an ASUS router to obtain the Channel State Information (CSI). However, I've encountered a recurrent issue: I keep getting incorrect amplitude values, which are often around the 1e9 range. These incorrect values can be seen across all the subcarriers. I acknowledge that there is a same issue #292, but the solution didn't workout. For clarity, I've attached a plot below (please note that the pilot and null subcarriers have already been removed).

image

Interestingly, when I filter out these abnormal sampling points, the resulting plot becomes much clearer, with amplitude values ranging from 0 to 10,000.

image

I'm trying to understand the source of these incorrect amplitude values. Does anyone know:

Any insights or suggestions would be greatly appreciated. Thanks in advance for your help!

BBJJCC commented 1 year ago

I had the same problem with some very large values in my data. So I filtered out all the numbers larger than 1e7 and got normal results. I'm also curious to know the reason.