LTE: How UE will detect Paging message when UE in IDLE mode

Question

How UE will detect Paging message when UE in IDLE mode, because when UE in idle mode it will not decode PDCCH but how it will come to know paging notification in PDCCH.

Answer 1

Hi, we can synthesize it like this:
• The UE may use Discontinuous Reception (DRX) in idle mode in order to reduce power consumption and subsequently increase battery life.
• UE reads SIB2 to calculate when to wake to monitor the Paging channel.
• When DRX is used the UE needs only to monitor one P-RNTI per DRX cycle.

Comments

Thank you,
How paging works in RRC connected mode.

Answer 2

Hi rohit,

In connected mode UE will be restricted only some set of RNTI's ( C-RNTI, TPC RNTI, SPS-RNTI) so it is not restricted to P-RNTI. even in DRX (RRC_CONNECTED) UE will be monitoring P-RNTI continuously so it can decode. refer 36.321 5.7