Hello Experts.
Can any one explain me about system constant Pa and Pb and there relation with CRSgain and pdschTypeBGain.
Vendor Huawei.
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You can read more from here: (@Ramanuj_Singh blog)
https://mytelcolearning.blogspot.com/2020/06/pa-pb-in-lte-and-its-impact-on-user.html
Source: mytelcolearning
Source: mytelcolearning
Seems TC2 is best.
Some parameters value pa, pb may cause RRU power is not fully utilized.
Huawei has a feature to utilize remaining power.
It is written that only 4 combinations allow full power utilisation:
Have you ever seen Pa = -6?
Yes, I have.
Parameter can be set, but actually does RRU run with this?
If it is set, it will run. 
You have the combination pf pa/pb -6/3.
I configured before during upgrade BW from 10 to 20M in order to maintain same power configuration
It was changed from -3/1 to -6/3.
-3 mean RS increased 3 dB by taking power from off CRS ports.
If -6 or 6 dB gain, RRU must take also power from other RE.
I am not sure RRU can do this or not.
In Huawei RS is configurable by parameter.
Pa/Pb will change non RS REs.
During BW upgrade from 10M to 20M.
Power per RE will reduce to half to maintain same RS configuration.
Since you doubled the number of PRBs.
If we change Pa and Pb and RS cannot substain that RRU goes down.
It’s a critical parameter.
Need to change very carefully.
Exactly but nothing goes down.
The system will reject the change and give error.
This is Huawei.
Í dont know other vendors.
I have done, cell down. So I know then you have to lock and do and unlock again.
Mmm weird. I tried many cases manually. Always giving error if configuration exceeds RRU capability
What is your SW version?