5G DL Reference Signal: 5G CSI-RS Channel State Information Part 1/2

[@aaronshi1]

Thanks well explained, expecting your part2 or part3

[@mohamedeladawiashour]

You are welcome, Part 2(final one) will be published this monday

[@sadanandan4554]

Very well explained. Doing good job. 👏🏻👏🏻. Let me know when part 2 will be published.

[@mohamedeladawiashour]

Thanks a lot, I am planning to publish the 2nd part by the end of this week.

[@chrts975]

This is really helpful thank you. Sth that still confuses me is the following. In theoritical papers CSI estimation is try to estimate the channel coeficient between transmitter and receiver through pilots and some technique like LS for example if i get it well , then this information is sent to the transmitter through some feedback. In contrary, in 5G the procedure is that the gnb sends the reference signals then the UE extracts some metrics from it like the CQI lets say from the SINR and then packs those metrics in the csi report. Then the gnb based on this report decides the mcs to use etc. So there is no channel coeficient information even for those REs the refernece signals map to?

[@mohamedeladawiashour]

Thanks a lot; this is a good question but i don’t have the answer now; i will need to read more for further understanding.

[@vicai008]

hi, Mohamed. Thanks a lot for the very helpful video. One question that still confuses me after watching the video is: in the “NZP CSI RS for CM & IM with Multi-User MIMO” part, when the UE 1 is conducting channel measurements using the “NZP CS CM”, this RE will also receive the interference from UE 2 and UE 3 since they are transmitting “NZP CS IM” with the same UE, will that be a problem since it is best that the channel measurement process is not affected by interference, right?

[@mohamedeladawiashour]

Hi Vicai, Sorry for the late reply, i missed your question earlier, regarding the interference point in all cases, we can't avoid the interference caused by the other co-scheduled UEs in MU-MIMO. So yes, as per my understanding, NZP CS IM transmitted for the other 2 UEs will cause interference but it will definitely have less interference impact compared to configuring all three UEs with CSI-CM. On the other hand, the resources configured for CSI-IM will help measure the interference generated by other UEs using CSI-CM. It's important to note that NZP CSI-IM is only used for CSI reporting and interference generated, while CSI-CM is used for many other purposes, such as CSI reporting, beam management, RLF detection, time and frequency tracking, beam failure, and so on." Please refer to page 220 & 231 in 5G NR in Bullets and pag 167 section 8.1.4 in 5G NR _ the next generation wireless access technology Books. Side note: the algorithm and the working mechanism of CSI-RS are quite complicated to me. I tried to go through the details, but at a certain point, I stopped looking for more information. This seems to be more related to the deep mechanisms implemented by 3GPP and vendors, which, from my perspective, may not add much value beyond what we are trying to gain from understanding vendors and related books.

[@mahboubehsedighizad]

Thanks Mohamed for your excellent explanation. Has the Part 2 been published or not?

[@mohamedeladawiashour]

Thanks, a lot

[@VipinKumar-dv7hy]

Very nice video..thanks

[@mohamedeladawiashour]

Thanks a lot vipin

[@nasrinmahami3387]

very good explanation, thank you

[@mohamedeladawiashour]

Thank you

[@anuragpatwa4337]

nice session , is it possible to cover in deep by the log?

[@mohamedeladawiashour]

Thanks a lot, Part 2 will be published tomorrow and covers the description of most of the parameters reported to control CSI RS Resources allocation in freq and time domain and other parameters. Other CSI "Channel state information parameters will be covered later in different videos.

[@pankajagrawal3925]

Thanks good explanation

[@mohamedeladawiashour]

Thanks, You are most welcome

[@shoaibakram4399]

really nice lecture..thank you

[@mohamedeladawiashour]

Thanks a lot, I am happy to hear that

[@aaronshi1]

Could you explain CSI-SSB resourceSet, was it for SSB beam failure recovery?

[@mohamedeladawiashour]

As per my understanding, an SSB Resource Set can be configured in addition to or as an alternative to the NZP CSI Reference Resources and this option gives the possibility of using Synchronization signals SS as an alternative to NZP CSI RS, which can be used for any of the functions mentioned in the video for CSI RS such as CSI Reporting and I believe it also it can be used for SSB Beam failure recovery, but i didn't find direct information to confirm this point.

[@aaronshi1]

@@mohamedeladawiashour Thanks, I thought it's for BFR purpose but 3GPP doesn't clearly mention. I would agree with you for the alternative measurmeent of NZP-CSI-RS , and even though SSB resource is kind of configured in CSI measurement configuration but it's linked to periodic SSB resources so no additional SSB resources are configured actually.

[@mohamedeladawiashour]

I am still searching for additional information and more detail about CSI SSB from 3GPP OR any other sources; the only information shared recently was found in 5G Nr in bullets; on all cases, I will let you know if reach into something and please also do the same in case if you found any additional info

[@aaronshi1]

Thank you~!@@mohamedeladawiashour

[@ahmedashour9254]

Thanks good job.

[@mohamedeladawiashour]

Thanks a lot

[@aaronshi1]

Could you also explain CSI_RS report from log analysis ?

[@mohamedeladawiashour]

Yes; this will be covered in the 2nd part

[@mahboubehsedighizad]

Sorry Mohamed, I saw the 2nd part right now. Best Regards

[@mohamedeladawiashour]

No problem at all, let me know if something missing. Thanks