LTE throughput in FDD but not in TDD

Hi All,
We have integrate new sector of 4T4R in TDD, and we’re getting throughput in FDD but not in TDD.
fdd but not in TDD (only a few kbps).
What can be reason?
Anyone has face this issue?

How is your SINR, RSRP, CQI, etc?

Everything is fine.
My TDD is proper in LTE but my VoLTE traffic is less as compared to FDD.
As my TDD is higher bandwidth of 15 MHz and FDD is 5 MHz on two carrier, and 10 MHz on one carrier.
Is it normal or should I optimise?

Globally people are avoiding VoLTE on TDD, except China.

Is it because TDD VoLTE capacity is less?


  • Poor Uplink.
  • TTI bundling doesn’t work on TDD.
  • It has been observed silent frames are more in TDD then FDD.

It’s due to strategy of LMS used on site.
For TDD due to massive MIMO implementation it’s recommended to move voice traffic to FDD so PRB utilization can be used more for data traffic.

So not to worry as PRB is balanced.

You can check Inter Freq threshold configured on site for QCI1.
Just check is it as per operator strategy or some Parameter Inconsistency on site.

Ok, no golden parameters given for that?
Need to check entire KPIs of site first?

Sometimes service based HO implemented which use to setup VoLTE call on particular layer and technology.
I saw after massive MIMO implementation, generally this trend observed that is VoLTE traffic more on FDD earlier, it’s not like that.

Yes as long as PRB utilization is fine it should be OK.
Because all LTE traffic is in high bandwidth, which is good.

Yes correct more PRB, more benefits in user throughput.
Just free some PRB.

It’s not PRBs, but its CCE which is the reason why VoLTE users are not kept in TDD/Massive MIMO cells.
Generally VoLTE bearers have higher scheduling priority that data users, hence more VoLTE users in a cell, less opportunity to data users, because most of CCEs used for Voice.
And PRBs becomes unused.

What is CCE consumption by VoLTE user?
We don’t have separate counters to check this.
For PRB utilization reduction I checked myself.

We have separate counters for CCE utilization/failure for data and voice dl/ul.
If we remove VoLTE users from TDD/MMIMO cells, spectral efficiency/throughput in TDD cell improves. Voice do not have much PRB utilization.

Yes, that is reason, difference from vendor to vendor.
I even find ZTE having mute call counters indication as well, which is missing in most of vendors.

I agree, counters may vary.
But goal is same - to save CCEs.

But scheduling strategy is Dynamic VoLTE in Huawei.
They don’t go for semipersistent at all.
When it is at certain threshold then only.

That’s why, dynamic require more CCEs.
Hence you should keep less voice users in TDD.