Need answers to important questions urgently, UL LA, DL LA, UL Power control

4G LTE
1

Hi All,

Can you please help me with the answers for following questions for LTE Layer2?

  1. How DL Link adaptation works at Layer2?

2)How UL Link adaptation works at Layer2?

3)How UL Power control works at layer2, what are the inputs to it?

Please help with hints or answers to these, as I’ve a important interview lined up within next 2 days.

Thanks much in advance.

Regards,
Rabindra

2

I can tell you how they work at least on 5G,

DL link adaptation depends fully on the pdsch harq and the WB-CQI. this two parameters would be used by ILLA/OLLA to propose DL msc to the scheduler. There are more detailed algorithm within. But summarily, CQI and A/N report would determine the how scheduler uses Msc. but the measurement is not done every time, it depends on the vendor. it can be done for some period like 10us aggerated result . The we have inside of the LA, the bler target and deltaCQI which is taken into use for the calculation.

the same approach is used for UL, but this time their is deltaSINR instead of delta CQI used inside of the LA

UL powor control, depending if it’s OLPC or CLPC… but for L2 to control or have any impact on power control, it’s likely CLPL… so TCP inside of DCI_0_1 would be used to tell UE to increase of decrease by certain dm… but it’s more complicated than that. please check sharetechnote and understand the calculation

3

Thank You for your response.