5G UL Reference Signals: (SRS) Sounding Reference Signal Optimization
ฝัง
- เผยแพร่เมื่อ 4 ส.ค. 2024
- This Video simplifies 5G SRS basic understanding and explains most SRS Related parameters and possible optimization actions. The below is covered in this video.
- Why SRS?
- How to check UE SRS support capability from traces
- SRS-related Parameter Overview
- SRS Vs. PMI(CSI-RS) weight-obtaining procedure
Materials added in the below link:
www.mohamedeladawi.com/5g-ul-...
0:00 Introduction
0:50 Why Sounding Reference Signal?
5:42 How to check UE SRS Support capability
7:45 Antenna Switching and Non-Antenna Switching Overview
13:38 SRS Parameters Description: Resource Type
15:06 SRS Parameters Description: Transmission Comb type
17:22 SRS Parameters Description: freqHopping(c-SRS & b-SRS)
20:00 SRS VS. PMI(CSI-RS) weight obtaining procedure
22:10 Optimization Action Summary - วิทยาศาสตร์และเทคโนโลยี
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Great Video as usual and just in time....Thanks again :)
حبيبي يا بيلو 😘
Thanks for explaining so nicely
Thanks alot, Navas
Hello Mohamed, Thanks for sharing. May I ask a question about the relationship between supportedSRS-TxPortSwitch IE and UL MIMO: If the UE capability of band N41's supportedSRS-TxPortSwitch=1T4R, does it means that UE cannot support UL 2x2 MIMO on band N41? Thanks.
As per my my understanding yes, it can’t support UL 2X2 MIMO as long as number of Tx branches is less than 2
a little update: checked a live network log, UL 2x2 MIMO can be used by UE when the capability is supportedSRS-TxPortSwitch=1T4R. In the RRCReconfig message, pusch-Config setup IE {txConfig codebook, maxRank =2}，and related srs-ResourceId{usage codebook, nrofSRS-Ports ports2}, then UE send out srs via 2 Tx (fixed conifured by RF), gNB set precoder layer=2 in DCI after few frames. @@mohamedeladawiashour
The cyclic shift part is not clear. With transmission comb size of 2, how can 8 UEs share the same REs ? If the SRS for UE1 occupies alternative REs in an RB then only another UE (say UE2 ) can occupy the rest of the REs. Thus, only two UEs can share the REs in an RB. I also read the 5G in Bullets book but it still is not clear.
The deep detail about it still also not very clear to me; It is a combination of code multiplexing and allocating different cyclic shift; i am trying to check different sourced to further clear the concept of cyclic shift. I will let you know if i reach into something
One doubt here ...case of 1T4R means UE has 1 transmit anteena and 4 receiving anttenas..correct....so in case of mumimo( suppose 2 Ues/device sharing same time and frequency resources)....how 1T4R will work ..means for 2 nd Ye how wil it do anttena switching?..
Hi Vipin; the question is not very clear to me; it seems I am missing something; we can have a one-to-one chat on Linked In to figure out the question and answer
Hey man apologies for my ignorance. SRS is sent by UE and decocded by gNB for channel estimation or beamforming etc... so then why there's a need to improve SRS coverage ? Wont that be mis leading for gnb?
If you can explain this point ... much appreciated OR it helps to formulate better beam forming... but then how?
Umm mm please if you could answer? Thanks
Hi man, no worries, it is the same concept as the DL, if there is a less power used by the bts the downlink coverage will be weak and probably the coverage demodulation process from the UE will result in reporting a poor CQI and as a result it will impact the link budget process in general which will result at the end in low Mcs, etc. the uplink is the same around, assume the UE is at cell edge the transmitted power of SRS might be insufficient accordingly this will still negatively impact the complete process as explained in downlink; as a summary improving SRS coverage will result in more accurate beam forming, higher mcs especially for EDGE users
@mohamedeladawiashour okies gotcha :) thanks .. I was looking from a different perspective, other than the obvious ...
Thanks once again. 🙏
@filthykid84 welcome anytime mate
Can you please confirm the following : 1)In case of Codebook transmission, Ue sends initially SRS and the gNB calculates the precoding matrix for PUSCH and sends to UE via DCI. 2) In case of non-Codebook transmission, gNB sends initially NZP CSI-RS then Ue calculates and sends the precoding matrices for PUSCH to gNB via SRS and gNb finally selects the proper one. Thank you
Hi georgeioskarouzos, Yes you are perfectly correct; you can find the clear procedure explained in pictures in 5G NR in Bullets book, Page 379 for Codebook based transmission and Page 380 for Non-CodeBook based transmission.
Thank you very much Mohamed.
@@georgioskarouzos7418 Thanks to you for letting me also review this information through sharing your valuable information and feedback
A UE capable of Channel Sounding without antenna switching transmits SRS less efficient than a UE capable of Channel Sounding with antenna switching. Is it correct ? Thank you
Hi Georgios, I didn’t find any related information to confirm your question. I will let you know here if i find any
You can refer to 5G NR in Bullets page 365 to 367. It covers all the information regarding antenna switching
Generally looks like so, having more diversity with higher Rx config.. seems the latter would be efficient
Please share link to the working material. Thank you!
Materials added to the below link. thank you
www.mohamedeladawi.com/5g-ul-reference-signals-srs-sounding-reference-signal-material/
Hi Thanks for that detailed explanation
One query as you told srs can be used for dl channel estimation as in tdd we have channel reciprocity so in that case why we are using csi for dl channel estimation csi report I..e why we need csi report
Hello, based on my limited knowledge, CSI is essential for DL due to two main reasons:
1- Not all UEs support antenna switching, which is a prerequisite for using SRS for DL channel estimation.
2- CSI provides better performance for EDGE users compared to SRS.
Thaanks Mohamed,
Can you share please the material of it?
Most welcome, you can find the working materials at the below link
www.mohamedeladawi.com/5g-ul-reference-signals-srs-sounding-reference-signal-optimization/
Thanks for this wonderful vedio..Any specific reason why srs always send on last symbols
Also request you to prepare vedio on csi rs ZP nd NZP its very confusing for me
Thanks 🙏
Thanks, a lot, i believe it is designed to be at the last 2 as SRS usually start special slot where it has Dl/GP/UL, so it should be at the end after the guard band symbols; regarding CSI RS, the video session should be ready by 29~30 of JUNE2023.
Can you please give ppt of this...also what does it mean 2t 2r....means ue side tx means srs transmission??? Rx means receiving at ue side?
Hi Vipin, You can find the working materials at the below link. Regarding your question, The UE transmits the SRS from each receive antenna
www.mohamedeladawi.com/5g-ul-reference-signals-srs-sounding-reference-signal-optimization/
@@mohamedeladawiashour thanks..in this video it was told that in case of 2t4r srs is transmitted using receiver….??? Why .. tx means at UE side is transmitter correct? Or tx means tx from gnb side??? Have confusion please clarify
Hi, it looks kind of complicated but whatever mentioned it is about the UE side; Antenna switching means the UE is capable of switching the transmit paths between ue receive antenna; refer to page 365 and 366 in 5G NR in bullets for more details.
@@mohamedeladawiashour thanks ..please make one more video that clears such doubts thanks in advance
One query can we use 1T4R srs antenna switching in mumimo ???
Yes it can be used, as per my understanding
@@mohamedeladawiashour thanks one more query it's written that for 1T4R case srs resources set could be zero or two..then what does it mean? Because at least one resources set should be there to map srs resources correct so confusing terminology zero or two..plz help
Hi Vipin, it is mentioned where? Speaking about 1t4R antenna switching, you should have two resource set id each will have 2 srs resources, have a look into page 366 in 5G NR in bullets book
@@mohamedeladawiashour yes for aperiodic case it is mentioned that zero or two..plz refer( I am unable to attach that link sorry) srs 5g sharetech note ..in that 1T4R aperiodic config
Hi vipin, i will have a look into and i will get back to you
Mate, great video and good material, unfortunately I hardy understand when you speak, it would be an amazing video if you slow down.. sorry
I cant agree more; i have to consider this part more in any new video
How do we do antenna configuration in antenna switching concept?
Hi; antenna switching is related to UE capability and it is working whenever you activate the advanced SU MIMO from gNB side and when the UE support antenna switching
Where can we find some example on antenna switching?
Very informative, but could you pls speak a little slower :))
Thanks, Farshad. I do agree; I need to slow down a bit
You speak too fast...little bit unclearly..(actually very unclear..why are you so hurry).. very irritating...
I agree; i am considering to slow down; it is getting out of control sometimes but i am working on it