Agree. UE sends *ue-identity* as the unique identifier, not TC-RNTI. I have added this correction in the description. Thanks a lot for pointing this error 🙂
Thanks for the video, it was very clear! I have a question, does this mean there is a miniscule chance of two UEs ending up with the same C-RNTI, if the selected ue-identity is also the same?
Correct. You got it. There is a slight chance for RNTI collision, which may lead to link failure and result in re-attempting the entire RACH procedure.
RACH procedure is used for multiple purposes. For initial connection, RA-RNTI is used, which is a temporary identifier for the UE. For reconnection purposes, C-RNTI is used (as shown in the video).
UE will not know. In contention based RACH procedure, a UE randomly choose a Zadoff Chu sequence, without knowing if any other UE also has chosen the same.
BS has to receive uplink signal from all UEs at the same time, i.e., time synchronized. So, far-away UEs transmit earlier than nearby UEs, so that all signals reach BS at the same time.
Very clear video with minimum time wastage. Loved it
Highly impressed with the content and the presentation. Looking forward to see more videos
Thank you! Will do!
Very very clear, thanks a lot！
Very well explained
Such this video is gold mind ❤
Very nice❤❤ thank you
Excellent video.
TC-RNTI is issued by gNB to UE in MSG2 first, not MSG4. The UE uses the TC-RNTI to scramble the uplink PUSCH message (MSG3).
Agree. UE sends *ue-identity* as the unique identifier, not TC-RNTI. I have added this correction in the description. Thanks a lot for pointing this error 🙂
excellent video
Thanks for such a brief video. Can you also make a separate video based on Zadoff Chu sequence, that would be incredibly helpful.
@02:30, it says, UE sends the message after time offset?! What exactly is time offset?
Time offset is to ensure that BS receives RACH within an uplink slot, not in any downlink slot. This is because, 4G or 5G doesn't support full duplex.
Appreciate your presentation. The topic is neatly explained in a simplest way. I saw very few videos. Could you please cover more topics. Thanks
Yes, I’m working on more videos.
Great
Dear @WirelessExplained, would it be possible for you to make an informatiove video on HARQcprocess overview, including ACK/NACK.
How does UE detect in which FREQ range are SSB transmitted ????
1:34 In 5G, 3GPP has defined a set of frequencies for SSB transmission. So, US has to scan all those candidate frequencies. Refer 3GPP TS 38.213.
Thanks for the video, it was very clear!
I have a question, does this mean there is a miniscule chance of two UEs ending up with the same C-RNTI, if the selected ue-identity is also the same?
Correct. You got it. There is a slight chance for RNTI collision, which may lead to link failure and result in re-attempting the entire RACH procedure.
Excellent. It would be great to do the same for 4G.
Thank you
When and where does RA-RNTI comes into picture???
RACH procedure is used for multiple purposes. For initial connection, RA-RNTI is used, which is a temporary identifier for the UE. For reconnection purposes, C-RNTI is used (as shown in the video).
First Question, how will one UE know which Zad Off Chu seq was selected by other UE??
UE will not know. In contention based RACH procedure, a UE randomly choose a Zadoff Chu sequence, without knowing if any other UE also has chosen the same.
What is the use of Timing Advance?
BS has to receive uplink signal from all UEs at the same time, i.e., time synchronized. So, far-away UEs transmit earlier than nearby UEs, so that all signals reach BS at the same time.
Handover video plz
Choosing another zadoff-chu sequence, to avoid collision.
vey nice