Atmospheric ducting impact in TDD layers

It’s about ducting intensity.
Usually about 15% after ssf7 to ssf5 change.
Sometimes > 24 hours ducting continuous.

Yes it is useful in ducting scenario but difficult to prove benefit in terms of RSSI

Hi LTE experts: Do duct Interference create issue for TDD only in 4G?

Yes, its impact is in TDD only - major dent on RSSI due to this its impact on traffic dip.

Gain is at the cost of DL T’put degradation.
I am saying that you can control accessibility part very well by changing SS5 instead of SS7 due to increase of Guard period in frame. But it will impact DL T’put with reduced number of DL Time slots in frame.
It depends on customer which things to tolerate in ducting scenario.
In my view, accessibility is more important than T’put in such cases.
At least end user can get small message with lower T’put.

Golden advise on ducting: Ducting scenario generally observed in morning & evening hours only (Typical time 5 to 8 AM & 7 to 9 PM) at time of temperature transition in atmosphere. You can very well isolate it with morning busy hour (typically 10 to 12 noon in mobile network).

If i understood, the interference exist also on LTE FDD in case of passive intermodulation e.g PIM?

Very hard to solve ducting only we change special subframe format or srs position.
It’s like God created phenomenon for telecom :grin:

:stuck_out_tongue: Agree, Man is still lagging to understand GOD’s magic…

Truely - also if not change the subrame then - some customer decide to change pririty from TD to FD for some relief.

It is our logic for customers, to get exclusion and keep meeting SLA.:crazy_face:

Ya, I remember Ericsson guys did it for Nokia circles and then we searching from where magic happens :wink:

Samsung is only vendor in the world I guess, who have developed feature.
In which every TDD cell can identify ducting intereference source and convert the source to SSF5.
Do anyone have this kind of feature?

Yes Nokia has advanced feature and maybe in subsequent release it will improve.

Its very hard control the impact of ducting :slight_smile:
We used to monitor through this website what is Ducting index for the week, i hope everyone knows it

https://www.dxinfocentre.com/tropo_sea.html

How is the ducting source identified?

Ericsson has similar feature.

Atmospheric Duct Interference is the Ericsson feature name, and has a “tolerance distance”.

Its run on server based tool basically. Every cell transmit one unique sequance…on detecting high intereference, victim cell provide detected sequency to server…and then ssf conversions hppen.

Same fundamental in Nokia feature.

And will it convert to SSF5, right?
So will be 9 symbols for GP.