Ever wondered what happens behind the scenes when your phone switches networks?
Let’s decode this critical aspect of mobility in wireless communication. 
Problem
Understanding how a UE (User Equipment) stays connected while moving is crucial for network engineers and testers. Yet, terms like Cell Selection, Cell Reselection, and Cell Redirection often confuse learners.
Solution
Here’s a simple yet powerful visual comparison to help you grasp these concepts.
Listicles – Key Takeaways:
Cell Selection
Happens when UE powers on or regains coverage
UE searches best cell based on S-criteria (RSRP, RSRQ)
No prior history used
Leads to initial connection
Cell Reselection
Happens in RRC_IDLE mode
UE evaluates neighboring cells periodically
Based on priority/ranking
Ensures better coverage without network involvement
Cell Redirection
Triggered post RRC release (e.g., after handover failure)
Controlled by the network (gNB/eNB)
Helps UE quickly connect to a new cell
Reduces delay and UE effort
Each of these steps plays a vital role in maintaining seamless connectivity and user experience.
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