Understanding Idle Mode in LTE Network

 Understanding Idle Mode in LTE Network

Idle mode in LTE networks enables mobile devices to operate autonomously, performing basic functions without constant interaction with the network.

There are 6 functions performed by LTE-UE in idle mode:

1️⃣ PLMN Selection:
PLMN (Public Land Mobile Network) selection is the process by which a UE (User Equipment) selects an appropriate network operator for communication.

2️⃣ Cell Selection:
Cell selection is the process by which a UE chooses an individual cell within a PLMN for connection

3️⃣ Cell Reselection:
Cell reselection occurs when a UE decides to switch from its current serving cell to a different cell within the same PLMN.

4️⃣ TAU (Tracking Area Update):
TAU is a procedure where a UE informs the network about its current tracking area to facilitate efficient paging and mobility management.

5️⃣ Paging:
Paging is the process by which the network notifies a UE of incoming calls, messages, or other data.

6️⃣ System Information:

System information refers to the broadcasted information that UEs use to access and operate within the LTE network.

-Today we will talk about PLMN Selection:

1️⃣ PLMN Selection Overview:
PLMN selection is a pivotal process wherein a UE (User Equipment) evaluates available network operators and selects the most suitable one for communication. This decision-making process is crucial for optimizing network performance and ensuring a seamless user experience.

🔲 Types of PLMN Selection:
There are two primary types of PLMN selection:
-Automatic PLMN Selection: In this mode, the mobile device autonomously selects a network operator based on predefined criteria, such as signal strength and operator preferences. This allows for convenient connectivity without user intervention.
-Manual PLMN Selection: Users have the option to manually choose a specific network operator from the available options. This mode provides flexibility, particularly in scenarios where users have preferences for specific operators or need to override automatic selection.

🔲 Home PLMN (HPLMN) and Visited PLMN (VPLMN):
-Home PLMN (HPLMN): The subscriber's primary network provider, where they subscribe to services and tariffs.
-Visited PLMN (VPLMN): A network operated by a different provider than the subscriber's home network. Divided into:
National Roaming: Roaming within the subscriber's home country.
International Roaming: Roaming outside the subscriber's home country.

🔲 PLMN Selection Process:
When a new SIM card is inserted, the mobile device initiates the PLMN selection process:
-RAT Procedure: Camps on the newest technology available in surrounding cells.
-Cell Ranking: Ranks cells based on the Best Received Signal Power (RSRP).
-Home PLMN Selection: Prioritizes the subscriber's home network.
-Fallback Mechanism: Falls back to 3G or 2G if the home network is not available.
-VPLMN Selection: Explores national and international roaming options if the home network is unavailable.