When data is on NSA mode how much throughput it takes in LTE as our anchor is through LTE?

5G NR
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1

Hi Experts,
When data is on NSA mode how much throughput it takes in LTE as our anchor is through LTE?
And RB consumption roughly in LTE.

2

Is parameter dependent.
MNO can decide how much goes on MCG cell and on SCG cell.

3

So normally what can be the ratio?

4

Up to you. 0% or 50% or 100%.

5

Zero means no data flow?

6

Yes, and value possible and configurable for Huawei.

7

So, will it be advantage for NR?
Then to have all the throughput?

8

Only for 5G capable UE with 5G services on SIM card.

9

So if it is NSA support ue and mcgcell is zero all data will be on 5G supported UE.

10

Yes except control plane that goes via mcg cell.
For RRC I mean.

11

It is also possible to distribute traffic per EPS bearer type, right?
I mean data can terminate on SCG and through 5G air interface.
Voice, IMS and Control Signalling through MCG through 4G air interface.
Right?

12

Right: All Voice, IMS and Control Signalling goes through MCG via 4G air interface.

13

According to my experience it is around 3% of the total throughput.

14

Which is that parameter?
Also we have seen cases where UL is completely on LTE in NSA mmwave mostly to avoid high power requirements at Ue side and poor RF diversity performance in mmwave UL due to less no. Of Tx Ue antennas in most devices . wud like to know the ntw config parameters which decides these proportions.

15

There are few of them, do a search in Hedex.
There is separate for UL and DL.

In Option 3x, the downlink data split mode is specified by the QCI-level parameter gNBPdcpParamGroup.DlDataPdcpSplitMode parameter on the NR side.

Downlink data is transmitted only on the MCG side.
When the gNBPdcpParamGroup.DlDataPdcpSplitMode parameter is set to MCG_ONLY, downlink PDCP PDUs for the corresponding QCI are all distributed to the MCG.

Downlink data is transmitted only on the SCG side.
When the gNBPdcpParamGroup.DlDataPdcpSplitMode parameter is set to SCG_ONLY, downlink PDCP PDUs for the corresponding QCI are all distributed to the SCG.

Downlink data is distributed dynamically.
When the gNBPdcpParamGroup.DlDataPdcpSplitMode parameter is set to SCG_AND_MCG, downlink data for the corresponding QCI is distributed dynamically.

There are many others impossible to list all. Just see Hedex is very clearly explained.
Just read this “NSA Networking based on EPC Feature Parameter Description”
In DL data split between scg and mcg is dynamically done.

Based on air interface capcity and delay of SCG and MCG.
Not many parameters to control data split in DL.
But in UL there are parameters to control how much goes on SCG or MCG.

16

Great info :+1:
So dynamic distribution may be the common one?

17

For DL, yes.
For UL is parameter controlled.

18

Yes mostly MCG only in mmWave.

19

SCG addition is controlled by data volume:
VOLUME_BASED_PERIODIC_TRIG_SW:On

20

When DL split bearer is dynamic, data is prefered sent via NR cell.
And if buffer delay is larger, gNB PDCP will route to RLC of eNB.
RLC of eNB periodic report status to PDCP of gNB, then gNB can estimate resource utilization & capacity of eNB.
There is also one parameter X2 interface bandwidth, if set to 100 Mbps for e.g., so LTE throughput can not reach over 100 Mbps.

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