How to Broadcast paging and SI's when ENodeB receives ETWS Indication.

Question

If once ENodeB recevies ETWS indication form MME, ENodeB should broadcast the paging message to all UE.

Inorder to send paging message with DL indication ENodeB will have UE_ID to calculate PO & PF to broadcast Paging message.

What will UE_ID in case of ETWS indication? How to calculate PO or is their any specific PO's which is their to broadcast?

Answer 1

Paging message is not always specific to UE but it may be relevant for all the UEs present in a cell.
As per RRC paging message definition, it contains ETWS indication flag when it is intended for all the UEs present in cell.
Each UE wakes up after its DRX cycle gets over and read the paging message from the paging channel, if paging message contains system information modification or etws flag, UE starts reading SIBs based on the received information.

Answer 2

Hi manohar,

For ETWS paging there is no need for ue_id because ENB is not transferring to particular UE, instead ENB will send paging in all valid paging occasion for the corresponding cell, so that all UE will receive the same in their corresponding SF. If ETWS flag is set in paging means UE will automatically acquire the SIB for further proceeding.

say E.g SF 5,9 is set as paging occasion for UE 1,2: ENB configured paging occasion is 0,4,5,9. So NEB has to transfer paging in all of these SF (0,4,5,9) so all UE will receive paging.

Comments

Hi ,
In which radio frame we have to send?
how much we have to keep on broadcasting?

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As per my knowledge that is implementation specific, we can send mainly on default paging cycle because all UE will receive at-least once in default paging cycle, remaining we have to keep sending in all paging occasion until our implementation specific count exceeds. UE paging occasion will be minimum of default paging cycle or ue specific paging cycle, so if we cover default paging cycle then all UE will receive paging between those RF.

Implementation is based on probability of reception.