Will signalling load/PRB utilization gets reduced if NGBR user inactivity timer is reduced or it will be opposite?
What do you mean by ngbr user inactivity timer?
Non gbr qci9 data inactivity timer.
It should be opposite, the lesser the inactivity timer, the more the user will do to idle mode and more the signalling will be needed to attach back to the network.
Ok. For high mobility areas like railway/highways, and crowded areas as well, shorter value will be recommended or longer value?
To be honest, I personally have never set different values for high mobility areas.
Higher values will need less signalling but will eat up you user license in case there is a limitation.
We changed this values in our project early days (in 2018).
We were performing a trial by changing System Constant SC 876.