Coverage reduction after change in CRS Port number

Hello,
In Huawei TDD_LTE, keep all other parameter fixed just changed the CRS Port number.
Coverage seems to be reduced.
Any idea why?

image

Power per port gets reduced.

Csi-rs ports are 3000s.
How exactly did you change them?

But MaxTxPower per Cell remains same.
Is there anyway to offset this drop in coverage?
Maybe with some boost in RS power?

Pdcchmaxcoderate value.

Check if you enable the Tx beamforming. If not, although the total cell tax power is same as before, multiple tx ports not only can’t bring any diversity gain, but may cause adverse random beamforming effects.

LTE coverage is measured by CRS power.
Cell power = channel_tx_power * no_of_port
Cell power also control by no of 20W power license bought.
So, if license total unchanged, no of ports increaed 2 times, RS power must be reduced 3db. So that, power per tx channel also reduced 2 times, ports increaed 2 times and total power the same as before.