Improve Rank2 MIMO ratio

Any suggestion to about how to improve Rank2 MIMO ratio?
Huawei system.
In some sites there are > 95% Rank1 samples.
UL RSSI is > 120 dBm.
Max TA ~500 m.

You probably have MIMO cable issues.
It is not possbile to have in normal situation rank1 > 95%.

Yes right, generally it’s like 60-40 ratio.

Rank 2 should be more than 30% everywhere.
Please check how each port of RRU is mapped to each antenna port.

The thing is, there single RRU running 2 carriers.
One of them have ~2% rank2, another ~25%.

How are the 2 antenna?
xPolar or space separated?

Is xPolar.

What’s the delta RSRP between those 2 during drive test?

Haven’t done DT yet … checking using statistics (% of rank1/2/3/4 samples).
TDD B38.
RRU & 4T4R.
All user device 2T2R (hence will not have >rank 2).

Check the RRU ports for thightening, jumper connectors for tightening and do a VSWR measurement. Eventually replace antenna, it may be faulty.

Hmm… gotcha.
Tomorrow will run a DT as well, let’s see what is the status on the field.

Seems tm1 there.
Look like single cable connected only.

But he said that rank2 is 2%, so both are connected.


Dual band antenna or tri band now possible most of time confusion there in cable connection from RRU.
Complexity of network increases.

Yeah, true.

If you have counter/oss feature like pmdeltasinr on Ericsson (LTE FFAX) that can show any RF or antenna or jumper problem on the site, you can get good indication from it.

Tried the cross feeder check of U2020 (Huawei).
Came out clean though.