Where do I learn about Spatial Frequency?


Please point me in the right direction to learn about the following:

  • Spatial Frequency?

It seems this term relates to MIMO and MU-MIMO in particular.
I understand that

  • MIMO relates to the ability for multiple streams of data to be transmitted on the same frequency simultaneously between TX and RX using multiple Spatial Streams;
  • This is achieved using OFDM

I see references to Spatial Frequency in these posts:
No Spatial Frequency
450m and Spatial Frequency usage
Different frequency on APs directed to each other

But no where in my reading about MIMO can I see a definition of Spatial Frequency.

Much appreciate any reply

Spatial frequency is used in relation to MU-MIMO, specifically the MU part aka Multi User. It doesn’t have anything to do with MIMO. That is why you can’t find any relation between spatial frequency and just MIMO.

As mentioned in one the posts that you listed, "spatial frequency is used to determine the beamforming to a subscriber (and can be thought of as azimuth, although 1 spatial frequency can map to 1 or 2 azimuth values).

The AP will send a special symbol to the subscriber to get the spatial frequency and evaluate the channel (e.g. for distortion etc)"

Once the spatial frequency information is acquired for an SM it can then be used by the AP to form optimized MU-MIMO groupings that allow different data streams to be sent to different groups/SM’s at the same time, increasing efficiency and aggregate capacity.


Thanks Eric. Again.
Best resources I have found so far are
PMP 450m Load Balancing - Video in the PMP 450 Series Certification Training (ID: E-VP5PXV)
and this interesting PDF. Good definitions in the PDF which I have struggled to find elsewhere:

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