RRC Connection Establishment

Unline in GSM, in UMTS Radio Bearers can be reconfigured.

To have basic clairity between RRC and RB : RRC is like rail track and RBs are like goods carrier which takes load.

Raching procedure (acquiring preamble) should happen before RRC Conn.Req received by NodeB

As connection can be raised because of N/w or mobile, the IE establishment cause explains the reason for the RRC Connection request

UE sends Initial UE ID (imsi/imei/tmsi) and this will be stored to send the same in RRC Connection Setup. When n/w sends RRC Conneciton setup to UE, UE verifies the ue id to validate whether the message is for self. If this is refering to self, then UE responds with RRC Connection SEtup Complete which will be the first message sent on DCH.

UE also includes measurement report SIB11 in RRC Connection request.

( UE To Utran )RRC Connection Request ------------------CCCH,RACH------------------------->>

(Utran to UE ) RRC connection Setup <<-----------------FACH--------------------------------- (New URNTI will be received by UE)

(UE to Utran) RRC connection Setup Complete -------------------DCCH--------------------------------->>