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seemoo-lab / mobisys2018_nexmon_channel_state_information_extractor

Example project for extracting channel state information of up to 80 MHz wide 802.11ac Wi-Fi transmissions using the BCM4339 Wi-Fi chip of Nexus 5 smartphones.
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Incomplete capture #18

Open dakami opened 5 years ago

dakami commented 5 years ago

Diving into the data a bit, i'm seeing that only about a quarter of the UDP payload data is changing from packet to packet. Seems strange.

AP is on channel 149, init string was:

echo "3cd0010080000000ffffffffffffb6fbe4196e08" | xxd -r -p | base64

pcap attached. (I sniffed the UDP traffic with tcpdump, dumped to a file, adb pulled that.)

mon2.pcap.zip

r array([[ 255, 255, 255, ..., -3315, 7193, -522], [ 255, 255, 255, ..., -3315, 7193, -522], [ -256, -1, -1, ..., -3315, 7193, -522], ..., [ -1, -1, -1, ..., -3315, 7193, -522], [ 0, 0, 0, ..., -3315, 7193, -522], [ 255, 255, 255, ..., -3315, 7193, -522]], dtype=int16)

gkpln3 commented 5 years ago

The same thing happens to me, any idea why? My guess is because we are capturing 20MHz on 5G channel.