I hope you can get the big picture of LTE call flow and take this page as a framework (or motivation) to study LTE. RRC security mode The eNodeB will reach the UE with RRC security mode message with the AS integrity protection and encryption algorithms and START parameters. One of these is the LTE call flow itself. Call flow is how signaling and sessions are created across an LTE network. The SCells are added either blindly or based on measurement event A4 whereas SCells are removed blindly when the UE moves to idle or the data transfer is completed. The message contains: configuration parameters for uplink RLC, UL-SCH, Power Head Room (PHR) and Uplink Power Control. Call flow is how signaling and sessions are established across an LTE network. On the other hand, PGW will also send Downlink data that will be buffered in the SGW for now. One of these is the LTE call flow itself. Session request Create session request message from the Mobility Management Entity (MME) to the Serving Gateway(SGW) to create a GTP tunnel. Call flow is how signaling and sessions are established LTE is a Packet only technology which is designed for handling data traffic. The UE sends back an EXTENDED SERVICE REQUEST (in both cases). Location update request Acknowledgment message sent from HSS to MME that contains PDN subscription contexts (EPS subscribed QoS profile and the subscribed APN-AMBR). Core netwwork elements(MME, HSS, SGW and PGW) The UE response message back to the MME with NAS ciphering and integrity protection. The UE in RRC_CONNECTED mode it is prepared to receive a CS SERVICE NOTIFICATION sent as a NAS message. When the measurement criteria is satisfied the UE sends measurement report to the network. The LTE call flow navigates over the elements of the network going through certain steps in order to complete its end-to-end signaling from the user equipment (UE) all the way to the rest of the network components. attach to both PS and CS services despite being on a PS-capable only network.The UE in RRC_IDLE mode is prepared to receive a paging message with a CN domain indicator pointing to CS. User equipments The SCell addition is done using the IE "sCellToAddModList" and removed using the IE "sCellToReleaseList" which is always sent in "RRC Connection Reconfiguration". LTE Call Flows Please Wait..Loading may take couple of seconds.. Email This BlogThis! In fact, call flow and signaling is unique for LTE, and is driven by 3GPP standards. Version Date Update V1.0 July 12, 2011 LTE Call Flows Main purpose of this document is to discuss LTE basic call flows.
Multiple SCells could be added and removed using a single reconfiguration message.LTE SCell addition and removal for Carrier Aggregation Basic State Machine For example, if UE wants to make a voice call, the network redirect the call to one of the existing technology like WCDMA or GSM. MO Call stands for Mobile Originating Call. Attach PDN request eNodeB will send its first message to the core network passing the attach request to the MME. There are two options of handling voice(CS) call in LTE.CS Fallback is normally done via the existing technology such as WCDMA and GSM where the calls are redirected to legacy networks.

Voice over LTE (VoLTE) Call Flow An iPhone setting up a VoLTE call with IMS signaling. The VoLTE call flow procedure covers messages exchanged between UE (or LTE mobile), LTE/EPC entities and IMS entities. With Long Term Evolution (LTE) comes a new and exciting attributes. ✔ MiniCore is a core network which is mostly used for testing, but can also act as the core network part of a mobile network for under 500 users. In such cases, the UE falls back to 3G networks to establish a voice call. default radio bearer. The UE sends to eNodeB acknowledge message that uses the newly activated keys to encrypt and integrity protection. Default bearer response The default bearer response from the PGW to the SGW will contain PDN GW User Plane address, PDN GW TEIDs User and Control Plane, EPS Bearer Identity and QoS. RRC reconfig eNodeB will send RRC reconfig to activate the In fact, call flow and signaling is unique for LTE, and is driven by 3GPP standards.
(but in LTE measurement based handover is used).Intra-LTE: The source and the target cell belong to the same LTE network.Inter-LTE: The source and the target cell belong to a different LTE network.