How to structure metadata for CSI frame

[luizfernandofo]

I'm in a project that we are collecting CSI data from a Intel 5300 NIC using PicoScenes Software. The CSI data is structured in the following way:

PicoScenes outputs a 57 sub-carriers x 3 antennas array, totalizing 171 elements. Each element is a cf64 number. There is also a Magnitude and Phase arrays in the same file, they are the processed complex number.

I've been reading the sigmf-spec, but I still did not figure out how to properly structure the sigmf-meta for this case. Should I specify in the num_channels field that we have 57 channels (sub-carriers) and have 3 separate sigmf-data files, one for each antenna, or should I specify 171 channels and have only one sigmf-data?

There are also Mag and Phase arrays, each containing 171 rf32 elements. How could I structure them?

Thanks in advance!