How to do configrations to make package loss and HARQ occurs between GNB and UE?

[Mac Millan]

Hi,

In order to design a congestion control algorithm, I need to form a playground that have package loss between GNB and UE.

But I've try the error model, set long distance between them, give bigger MCS. There still no HARQ NACK occurs in my simulation.

How can I set a good configration to make it happens?

Thanks a lot!

[Gabriel Ferreira]

It will usually happen due to fast fluctuations of the channel.
Since it is hard to get these while static, best thing you can do is to find a fixed MCS for the particular scenario you have in mind, which has a higher error rate, but not that high as to make the communication inviable.
What I do when testing harq is hardcoding the error rate by changing https://gitlab.com/cttc-lena/nr/-/blob/master/model/nr-spectrum-phy.cc?ref_type=heads#L1632
to

tbInfo.m_isCorrupted = m_random->GetValue() <= 0.5; //  tbInfo.m_outputOfEM->m_tbler