No Spatial Frequency

Products PMP
1

Hi,

What does the following mean?

Under Sounding Statistics

No Spatial Frequency


Paul 

2

Hi Paul,

I assume you are looking at a 450m to see this.

The 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 subsciber to get the spatial frequency and evaluate the channel (e.g. for distortion etc)

For MU-MIMO and beamforming to a subscriber the spatial frequency and a good channel estimate are needed (this will then display a spatial frequency and 'TRACKING' as the sounding state, if the channel estimate has problems it may show 'UNTRUSTED' or 'ASSESSING' in the sounding state).

If the SM is running old software (older than 15.0 I think) then it cannot workout what to do with the sounding process and it will fail, as will a PMP430 SM.

best regards,

Andy.

1 Like
3

Thank you Andy,

I will have a look. Would a SM like this affect the performance of the AP?

The Software package is 15.2 and the signal on the SM is really good.

Paul

4

Hi Paul,

If there is no spatial frequency then the SM cannot be included within a MU-MIMO group so cannot contribute to multiplexing gain. The 450m can cope with this but it will bring down overall maximum sector performance. How much depends on how much traffic this particular SM is requesting. It may take a minute or so from when the SM first registers before a spatial frequency is calculated.

If you have checked that the s/w version is OK at both ends and the SM Rx power is good then we can collect some diagnostics to investigate further.

If we do need to investigate then message me direct on here or at andrew.rimmer@cambiumnetworks.com , and/or you could raise a support ticket :)

best regards,

Andy.

5

Hi Andy,

Thanks very much for the assistance.  I will have a look and if i need further help i will come back to you.

Paul