Throughput versus Rank3 and Rank4

4G LTE
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1

Dears

I am having a problem related to Throughput and Rank3 and Rank4.
The network that I am working uses the frequence of 2500 MHz (TDD) in Fixed Wireless configuration.
The complain is about rank3 and rank4 time percentage.
Since previously this network was Huawei with rank3 and rank4 reaching up to 60% of samples, but after the swap for Ericsson it does reach even 10%.
The network site that we are analyzing is using 20 MHz + 20 MHz, with 4T4R but just reaches 290 Mbps using NetPerf.
I worked with Ericsson 7 years ago and It would amazing your support at this rump up knowledge time.

2

It is based on the available bandwidth.
Say 5M Hz to 20 MHz in the same cell (say 3 layers having 20, 10, 5), then 5 is what you need to consider for FDD.

3

Make sure beamweights are based on SRS.
Don’t know the name of parameter for Ericsson but Huawei uses SRS weights up to srs sinr = -23 dB
SRS is more precisely than csi-rs.
You may want to check antenna cables to be correct at RRU to reach MIMO rank 3 and rank4.

4

Do you mean verify VSWR of cable connections?

5

Check connection from rru port to antenna port physical.
Rank3/4 ~ 60%: from DT log or omc kpi?

6

It is important how you correctly connect ports A, B, C, D of RRU to antenna ports +45 and -45 degrees.
Make sure I&C of Ericsson is correct regarding MIMO cables.

For Huawei, in Hedex you can look for Antenna Port Mapping table, with the mapping between logical antenna ports and RRU channels. There you find recommended configurations for different connections.

7

It’s OMC KPI.

8

LTE rank 3/4 ~ 60% samples is too high, I suspect about this percentage.
Because it require very high sinr + high user traffic to reach 4 layers.

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9

It can be, it is about the rich multipath of the cell and users location.

10

60% (rank3 + rank4).

11

I am also interested to know how to achieve this much.

12

This is absolutely RF depending.
It’s not something to tune on parameters.
Only cells with rich multipath can achieve 60% rank3 and rank4.
Huawei however have hidden params to tweak/increase the rank utilisation.

13

Exactly, you need to have perfect RF conditions to have this.
Even if you have parameters there is no alternative to having better RF conditions.
These figures speaks of a special case but do not reflect the whole network.

14

If field test at a good point I think can reach 60%. But whole site, it’s impossible.

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15

So what’s Huawei’s best throughput compared to Ericsson’s 290mbps using Netperf

16

If it is 290mbps x3 or above, I think it may not be possible.