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seemoo-lab / nexmon_csi

Channel State Information Extraction on Various Broadcom Wi-Fi Chips
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sequence number problem #365

Closed kuku000 closed 1 month ago

kuku000 commented 1 month ago

Hello,

I am currently using Raspberry Pi 3B+ to extract CSI data from a wireless card and transmitting it via UDP to a client for analysis. During this process, I have noticed that some packets have repeating seq no values. I would like to understand if this is related to packet retransmissions, and whether it could affect the accuracy of CSI data or the final analysis results.

Specifically, when there are consecutive packets with the same seq no, could this lead to inaccuracies or misinterpretation of the data? Would repeated seq no impact applications like CSI-based fingerprinting or other similar uses?

I greatly appreciate your assistance!

Thank you!!!

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jlinktu commented 1 month ago

If you are talking about the sequence number fetched from the IEEE 802.11 MAC header, then no, this should not affect any CSI interpretation. A retransmission on IEEE 802.11 MAC layer requires a full retransmission on the PHY layer, which means, besides carrying the same payload, is more or less independent of the former transmission.

kuku000 commented 1 month ago

Thx !!!