Understanding 450m frame utilization?

Ok trying to understand frame utilization vs congestion on a 450m and if i should be waiving the "add a carrier" flag... 

In the below pic 72% utilization, but frame utilization is saying its 99%.

On a 450i i consider this hard line congestion and would have upgraded to a 450m, but with the 450m i don't know which value really means things are becoming an issue, i'm considering an additional carrier and splitting the load.

Based on multiplexer gain and the latest throughput calculator for 450i/m, we should be seeing ~177aggregate at 1.47 but if the frame utilization is to be believed we're topping out at 80mbit ...


Hello CSup,

You're right, PMP450m is capable of carrying additional downlink traffic when the Frame Utilisation 

reaches 100%. The 100% figure simply means that all of the downlink slots are carrying data - MU-MIMO 

operation permits these slots to carry data to more than one SM at the same time. I tend to think of this 

as stacking more data in each downlink slot. 

I posted some diagrams a while back to illustrate MU-MIMO operation:


For non-MU-MIMO systems Frame Utilisation is a good indication of congestion. However, with 

MU-MIMO the amount of additional data is dependent on a number of factors - including the 

spatial arrangement of the SMs which require data at any particular time. The Statistics -> Frame Utilization 

tab highlights this in the Spatial Utilisation table - you can gauge the congestion particular directions 

from this. MU-MIMO significantly increases the sector capacity but the simple Frame Utilisation 

figure becomes a less useful indicator of congestion.

It may be that the PMP450m is simply meeting the demand.

This post contains more information about the MU-MIMO metrics:


If you are able to capture some field diagnostics (http://AP_IP_ADDRESS/field_diags.cgi) during a busy time

on your sector I would be happy to review them.

Best regards,




A great reply, i sent you a field_diags as well