Paging difference between 3G and LTE

Question

Want to know about how paging working in telecom network and what is the difference between paging in 3G and Paging in 4G-LTE network.

Answer 1

I have worked only in 4G network so I can explain how paging work in lte.
Paging and DRX (Discontinuous Reception Cycle) are much related. Paging is used to inform to UE that CoreNetwork has received some data for you so attach to the network to get your data. when UE is in idle mode (I mean there is no radio connection between UE and Enodeb) it enters into DRX mode in which it sleeps(does't read PDCCH channel) and save its battery. After some configured period of time (DRX-config has info) it again wakeup and read PDCCH for P-RNTI(Paging indentifier). Both MME and UE has imsi details. At initial point of time while attaching MME generates UE Identity Index value (see 36.413) with UE imsi. UE also do the same think at its own end. There is a concept of Paging Frame(which radio frame) and Paging Occasion (subframe in side Paging Frame). Paging Frame and Paging Occasion calculation done at Enodeb and UE based on UE Identity Index value value, which is communicated by MME to Enodeb. so UE knows to which radio frame it has to read and which subframe of that radio subframe. In this way, every time Ue wakeup at particular subframe and read PDCCH for P-RNTI and once it validates P-RNTI, it read further for paging-indexity(See RRC paging message). if paging identity is present then UE NAS initiate Service request message in attach procedure.

Please let me know if I am wrong at any place.

Comments

For the Voice call we have only one paging request that is our incoming call which arrives in paging channel (downlink only).
So in UMTS-data that is from the SGSN/GGSN the paging is of two types. Paging type 1 and Paging type 2. These selection of paging depends upon the RRC state. RRC has four states. 1. CELL_DCH,  2.CELL_FACH, 3.CELL_PCH and 4.URA_PCH. In first two states the incoming call will come through paging type1 and if the user is in other two states of RRC then the paging type2 will come.

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Hi Hiteswar,
Paging type 2 is used in Cell_DCH and in Cell_FACH state not in Cell_PCH and URA_PCH. Thats why Paging Type 2 is known as UE Dedicated paging.
Brief is:
Paging Type 1: This message will be sent to the UE, when UE is either in Idle State, Cell PCH State or URA PCH State.
Paging type 2: Known as UE Dedicated Paging: This message will be sent to the UE, when UE is either in CELL DCH State, Cell FACH State or CELL_PCH (FDD only) state.