Collecting CSI in Monitor Mode

[navidtadayon]

Hi there, I sent you a message a while ago and asked you a question about this CSI tool. Thank you for doing the superb job of developing this tool and making it available to the community. I have been struggling for long with the following problem: I am able to collect CSI in master mode. What I need to do is to be able to collect CSI when the receiver is in monitor mode. The reason I insist on this is that, in monitor mode, steering matrices from more number of channels can be collected within a given amount of time. However, as soon as I put the receiver in this mode, nothing is collected. When I inspected your modified driver code, I realized that rx_not_sounding=1, rx_hw_upload_data=0, rx_hw_upload_data_valid=0, rx_hw_upload_data_type=0. These values obviously block the driver to collect anything. In fact, they might mean that there is nothing to collect! I do not understand why this is happening since (according to my way of working out the theory) ath9k requires steering (CSI) matrix for decoding HT packets in monitor mode, so the latter will have to be calculated by the driver no matter in which mode (what do you think?). On the other hand, above-mentioned parameters are calculated based on 11 words of RX descriptor that is made available by the driver in ar9003_mac.c. This makes me believe that, perhaps, Atheros cards do calculate steering matrices in monitor mode but do not upload it on the hardware. Long story short, I am seeking your advice! In particular, I read your paper "precise power delay profiling using commodity wifi" and it seems you were able to do the same thing that I need to do... Any feedback is highly appreciated.

[ypan314]

@navidtadayon I encountered the same problem, did you solve it?