Why does your phone’s speed drop from 150 Mbps to 20 Mbps as you drive away from the tower?
It’s not just signal strength — it’s intelligent adaptation happening 20+ times per second.
I’ve just published a detailed guide explaining how LTE 4x4 MIMO actually works in real networks. Instead of dry theory, it follows a single user’s journey from the cell center to the edge.
Here’s what happens:
Near the tower: Your phone tells the network, “I can handle 4 data streams, signal is excellent!” → The eNodeB sends 4 simultaneous layers
→ Result: 150+ Mbps download speed
On the highway at 100 km/h: Your phone: “Channel is changing too fast for precise aiming” → The network switches to robust spatial multiplexing (no PMI feedback)
→ Result: 60–90 Mbps with a stable connection
At the cell edge: Your phone: “Signal is weak, I can only handle 1 stream” → The network sends the same data redundantly from all 4 antennas
→ Result: 10–20 Mbps, but the connection stays alive
The guide covers:
- How CSI feedback (CQI, RI, PMI) drives real-time decisions
- When Transmission Modes (TM2, TM3, TM4) are used and why
- What operators need to configure for successful 4x4 MIMO deployment
- Real KPI traces showing SINR, Rank, and throughput evolution
Written for both experienced RF engineers and newcomers to MIMO technology.
Download the full guide: 
LTE 4×4 MIMO Explained – From Cell Center to Cell Edge (by Alali Khalaf).pdf (29.1 MB)
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