Why in RRC-connected mode, UE still receive paging messages?

Hi All,
Anyone can explain why in RRC-connected mode, UE still receive paging messages?

It’s seen always in live networks, many times.

This is ShareTechNote explanation of Paging in Connected Mode

In most case, Paging message is transmitted from network and monitored by UE while UE is in Idle mode. But there are some cases where Paging is transmitted and should be monitored while UE is in Communication State. In this case how often (meaning at which timing) UE has to monitor Paging ? In case of WCDMA, it was simple because when UE is in connected mode Paging is delivered to UE via DCCH. So UE doesn’t care about Paging detection timing (actually UE does not monitor PCCH unless UE is in PCH), but in LTE UE has to get the Paging through PCCH regardless of whether it is in Idle mode or Connected mode. Therefore, in case of LTE monitoring timing of Paging need to be considered even in the connected mode.

https://www.sharetechnote.com/html/Paging_LTE.html

Paging can be for SIB modifications, etws warning also.
These messages need to read by UE even in connected mode.

2 Likes

This is normal paging:

Without SIB modification and etws, as well seen.

I even seen same.

In LTE UE has to get the Paging through PCCH regardless of whether it is in Idle mode or Connected mode.
Therefore, in case of LTE monitoring timing of Paging need to be considered even in the connected mode.
So LTE UE must always monitor paging channel even in idle or connected mode?

Yes, right.

Which NE is responsible for paging trigger? MME?

MME, I think.

If UE in connected mode, and UE has downlink data, will MME send paging or always not?

Both MME and eNB.

It will send so UE can come to conncted mode by service request procedure, otherwise not send.
Actually this type of paging come to bring UE in connected mode once it go to idle by inactivity timer.

I mean UE is currently in RRC-conneccted mode and PDN network send UE some data, whether MME will send paging to UE or never in this case?

I think no in this case as it’s already in connected state.

Paging message what you shown I even seen many times in connected mode but still I didn’t have idea what need of these paging message…

Will not send.

This is needed for another UE, but this UE in connected mode still has to read/decode paging.

Yes, increasing delay.

Paging msg is is broadcast message. Sent to the group of UEs and it is scheduled of fix DL RBs.
So even if it is not intended for particular UE, it has to read that paging and confirm if it is for that UE or not.

You can see UE identity here.

I know it: for VoLTE, MT UE in idle mode must receive paging first.
Because paging of another UE.
This UE only read/decode PCCH.
If UE is downloading data, RRC-coneccedted mode for internet PDN. Is UE also in connected mode for VoLTE?