LTE: CQI value question

[Rui]

In the trace ns3::LteUePhy::RsrpSinrTracedCallback, the sinr values can be obtained. In the function LteAmc::CreateCqiFeedbacks (const SpectrumValue& sinr, uint8_t rbgSize), the input must be the SpectrumValue. How can we get the CQI values using the sinr values?

Appreciate for any help!

[Tom Henderson]

I looked into trying to trace CQI values a couple of years ago and
concluded that it could not be easily done without modification to the
LTE source code.

On the UE side, the LteAmc object that generates CQI values is not
presently configured to be accessible by a Config path:

https://www.nsnam.org/docs/doxygen/classns3_1_1_lte_amc.html#details

The LteUePhy object that calls LteAmc can be found, so that is an option
(to add a trace source there):

https://www.nsnam.org/docs/doxygen/classns3_1_1_lte_ue_phy.html#details

The other option is to trace on the eNB side. I created a small patch
to do this from the RrFfMacScheduler, which worked for me, but is not a
general solution(would need to be added to all schedulers, or located
somewhere else in the eNB stack):

https://gitlab.com/tomhenderson/ns-3-ee-595/-/commit/87704f9bacba907fe4122e8e40e08cf8b90bf476

- Tom

[Roland Martinson]

Hello Tom, thanks so much for the solution. I have used your patch (with the updated RrFfMacScheduler) and set up the callback function but was not able to get the CQI value. Only the rnti value is being tracked? What could be the problem?