From the course: 4G LTE: Architecture, Protocols, Call Flows, KPIs, Optimization, Performance Analysis

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Initial access call flow and message flow in LTE

Initial access call flow and message flow in LTE

Have you ever wondered what is really happening in the 2 seconds between turning on your phone's data and seeing those signal bars light up. It is not magic. It is a high speed conversation. Let's follow that conversation step by step to see how your phone gains access to the network. And this journey from your device to the network core is called the initial attached procedure. This entire process is like your phone formally introducing itself and getting a pass for the network to get in. The journey begins with your phone finding and syncing up with the cell tower. Your device listens for basic signals from the towers like PSS which is primary synchronization signal and SSS which is secondary synchronization signal to lock onto the strongest cell. It It then downloads system information which is broadcasting continuously, essentially reading the tower's rules and identity. To officially say hello, the phone sends then a random access preamble. The tower responds saying I hear you…

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