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open-sdr / openwifi

open-source IEEE 802.11 WiFi baseband FPGA (chip) design: driver, software
GNU Affero General Public License v3.0
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CSI data source #157

Closed Eugene-Liu-Incubator closed 2 years ago

Eugene-Liu-Incubator commented 2 years ago

Hi, I am looking to do some experiments with SDR using openwifi on Analog Device adrv9364z7020 hardware.

I am using 802.11a to my experiment, and I would like to know the source of CSI in Openwifi.

Is it comes from long training symbol in I/Q ?

Or only the pilot subcarriers (-21, -7, 7, 21) in long training symbol and interpolation to all subcarriers ?

Thanks for your openwifi project, this quite helpful for us to improve our research.

Sincerely, Eugene Liu.

JiaoXianjun commented 2 years ago

csi comes from long training symbol. after fft on the long training symbole, csi = Y/X on each subcarrier of long training symbol. Y is the received subcarrier signal in frequency domain. X is the known subcarrier symbol in frequency domain (defined in standard).

Eugene-Liu-Incubator commented 2 years ago

Thanks for your reply !