Shulou(Shulou.com)06/03 Report--

End to End call flow Overview

1. After booting, the NAS layer initiates a service request to RRC, and RRC initiates a process of frequency scanning and system information acquisition.

2. Once the frequency scanning, SIB acquisition and cell residence are completed, RRC configures the underlying layer and informs the NAS layer that services can be obtained.

3. At this time, the NAS layer begins to initialize the conversation service, but the UE has not been connected to the network, so it is necessary to establish a RRC Connection to establish the SRB and complete the registration of the UE.

4. RRC initializes the Random Access process by sending a request from RRC Connection Setup. During the establishment of a RRC connection, (and Cell Update procedure) NodeB will know the capacity of MS. When the RRC connection is established, UE may report its own capacity,capacity in RRC Connection Setup Complete as a basis for later inter-RAT switching.

5. NAS initiates a service request to the network, and the network initializes the establishment of NAS security level, followed by the establishment of AS layer security. After the security is established, NAS sends a call setup to the network, and the network responds to the request through the call processing process.

6. At the AS layer, the network initializes a RB establishment process to establish the voice RB for the conversation. Once the underlying configuration is completed, the RB setup complete is sent to the network.

7. NAS will be indicated that the RAB has been established, the network will send an altering/connect to the NAS for the voice call, and after the NAS replies to the connect act, the voice conversation will be activated.

8. If the call needs to be stopped, NAS initializes the disconnect and the network responds to it.

9. The network starts the RRC ConnectRelease process and stops all RB.

Question: are uplink synchronization and downlink synchronization implemented during frequency scanning, SIB acquisition or RRC connection?

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