PDCCH CCE utilization equ

[mohamed_zakaria]

Hi Ericsson expert

We have clipping in PDCCH CCE utilization equation at 70% , equation output is average
Also the PRB utilization is around 60% however the user number is around 300 user
Any clue for that strange behavior . Thnx

[kher09]

I have also been with a similar problem, and found another post here.

PDCCH Congestion

Hello experts, It is said when PRB and CCE utilization is high, one method to resolve the issue is to reduce control channel resources .whereas i also know that in good radio condition, CCE utilization increases with increasing number of users which implies using higher symbols for pdcch (3 symbols). So if reducing control channel resources allocated for pdcch despite having high users in the network, will this not have an impact on end user’s experience?

Basically they recommend checking these 3 parameters:
pdcchCfiMode = CFI_AUTO_MAXIMUM_3
pdcchLaGinrMargin = 50
pdcchPowerBoostMax = 2

In addition to that, I found (and it worked better in my case) to activate 2 features:
CXC4011482: Enhanced PDCCH Link Adaptation
CXC4011515: PDCCH Power Boost

This last feature is necessary for pdcchPowerBoostMax to work and make sure you lock/unlock the cell for the change to take effect.

Finally, make sure that your cell does not have over propagation, I had this problem in 1 cell and even if I made the aforementioned changes, the problem did not improve much: the cell reached 15km.

[Pirm]

@kher09

pdcchCfiMode

5(CFI_AUTO_MAXIMUM_3): As VoLTE is a service with a high packet frequency a high number of scheduling occasions are needed. This will lead to a utilization of a high amount of PDCCH resources, hence it is recommended to configure the PDCCH to have a high capacity. It is recommended to set EUtranCell.pdcchCfiMode to 5 (CFI_AUTO_MAXIMUM_3).

[Pirm]

@kher09

pdcchLaGinrMargin

pdcchLaGinrMargin = 100, GINR back-off parameter for PDCCH link adaptation. Applies to all UEs when the feature Enhanced PDCCH Link Adaptation is disabled. In FDD, if the licenses for both Enhanced PDCCH Link Adaptation and Carrier Aggregation are enabled, this parameter applies to secondary cell PDCCH for UEs capable of carrier aggregation.

[Pirm]

@kher09

pdcchPowerBoostMax

pdcchPowerBoostMax: If set to 0, there is no PDCCH power boost of the maximum CCE aggregation level. PDCCH coverage is not increased but the feature still optimizes the PDCCH power setting for PDCCHs that require equal or less CCEs than the maximum CCE aggregation level. This still allows for higher PDCCH capacity.