Call setup procedure. Quick Reference

Following is the over protocol sequence being exchanged between UE and Network. Actually understanding all the details of these steps would be the goal of your whole LTE career.

1) <Cell Search and Detection>

2) MIB

3) SIB 1

4) <Check Cell Selection Criteria>

5) SIB 2 and other SIBs

6) RRC : PRACH Preamble

7) RRC : RACH Response

8) RRC : RRC Connection Request

9) RRC : RRC Connection Setup

10) RRC : RRC Connection Setup Complete + NAS : Attach Request + ESM : PDN Connectivity Request

11) RRC : DL Information Transfer + NAS : Authentication Request

12) RRC : UL Information Transfer + NAS : Authentication Response

13) RRC : DL Information Transfer + NAS : Security Mode Command

14) RRC : UL Information Transfer + NAS : Security Mode Complete

15) RRC : Security M ode Command

16) RRC : Security Mode Complete

O1) RRC : UE Capability Enquiry

O2) RRC : UE Capability Information

O3) ESM : ESM Information Request

O4) ESM : ESM Information Response

O5) EMM : EMM Identity Request

O6) EMM : EMM Identity Response

17) RRC : RRC Connection Reconfiguration + NAS : Attach Accept + NAS : Activate Default EPS Bearer Context Req

18) RRC : RRC Connection Reconfiguration Complete + NAS : Attach Complete + NAS : Activate Default EPS Bearer Context Accept

O7) EMM : EMM Information

19) RRC : RRC Connection Release

20) <Perform Neibourcell Measurement>

21) <Check Cell Reselection Criteria >

22) < MO or MT call > : In MT call, Paging should be sent.

23) RRC : PRACH Preamble

24) RRC : RACH Response

25) RRC : RRC Connection Request

26) RRC : RRC Connection Setup

27) RRC : RRC Connection Setup Complete + NAS : Service Request

28) RRC : Security Mode Command

29) RRC : Security Mode Complete

30) RRC : RRC Connection Reconfiguration + NAS : Activate Dedicated EPS Bearer Context Request

31) RRC : RRC Connection Reconfiguration Complete + NAS : Activate Dedicated EPS Bearer Context Accept

32) RRC : RRC Connection Release

Source: sharetechnote