Will CFI be equal 3 for 1.4, 3 and 5 MHz system bandwidths in all cases?
For 1.4 MHz we can have 4 OFDM symbol for PDCCH.
CFI indicates how many OFDM symbol per subframe for PDCCH.
CFI 3 means 3 symbols can be used for PDCCH I think dynamic CFI is used in all vendors.
Phich will only be in first symbol depending on ng factor.
And if high BLER better to use ng factor as 1 or else ng half can do.
Symbols to used for PDCCH need to defined as per bandwidth.
Once we have symbols for PDCCH then we can use feature load based PDCCH, etc.
But initially we need to tell UE number of symbols.
Dynamic CFI in Huawei is mainly used for 10 and 20 MHz.
And it has it advantages, as already they have the resource available.
As it varies depending on load for scheduling UE.
Because in good RF we can have 2 CCE, but in poor RF it takes 4 or 8 CCE.
Dhangle LTE is a better think to understand.
It means Huawei don’t have parameter like
It has the calculation for rb depending on factors.
That is dynamic CFI.
Is it decided on basis of bandwidth dynamically?
It has, but dynamic CFI is adopted by default max will be 3 in LTE and can vary adaptively depending on CCE utilization.
It has so much parameters for PDCCH.
Lot of tuning is there from maxcode rate and in poor to agg 8 CCE users to 4 CCE, it also has some parameters.
8 cce can allocated DCI format accurately to UE, but congestion occurs that’s the drawback of LTE so some power parameters is there to shift 8 CCE to 4 CCE.
In poor RF scenarios.
If BW 1.4 MHz, then CFI is 4, we can go.
What can be the downside of reduced it to 1/2 in highly loaded conditions?
Bandwidth obviously plays a part.
If BLER is high, the symbols of other resources will be used.
For PHICH that’s the downside.
Otherwise no issue if BLER is not so high.
Non adaptive retransmission case in Uplink.
What values of BLER you consider to be safe?
Initial target BLER in non GRB is kept 10, but in GBR it’s zero.
In high loaded conditions and after using all the PDCCH Enhancements, this option is to go for.
CQI relation is there with retx in 3gpp.
Can be ng last option if up bler is high, in Uplinl.
It’s like 2% for VoLTE.
It’s a comprising on quality part but kept now a days.
I think RLC AM is used in QCI1.
Which is shocking to know.
For QCI is not used AM RLC mode.
The more the retx, the more voice quality will be affected.
RLC UM is used.