● HARQ Pipeline & Stop-and-Wait Viewer
LEO · RTT 25.8 ms
🖱️ Click Start to begin data flow simulation
📊 RTT 25.8 ms
📈 HARQ Processes 16
⏱️ TTI 1.0 ms
📊 Throughput 0.0 Mbps
Throughput: 0.0 Mbps
Optimal HARQ Processes~26
Pipeline Efficiency0%
Active Processes0/16
Status⏸️ Stopped
Click Start to begin simulation
Idle
🎯 Learning Outcome: This lab demonstrates the HARQ stop-and-wait problem in NTN.
The optimal number of HARQ processes is approximately RTT / TTI.
📌 STALL SCENARIO: ❌ GEO (RTT=541ms) + 16 HARQ Processes
→ Optimal ~541 processes. With only 16, pipeline stalls!
Efficiency drops to ~3%, throughput is minimal.
→ Optimal ~541 processes. With only 16, pipeline stalls!
Efficiency drops to ~3%, throughput is minimal.
📌 NO STALL SCENARIO: ✅ LEO (RTT=25.8ms) + 32 HARQ Processes
→ Optimal ~26 processes. With 32, pipeline flows continuously!
Efficiency >90%, throughput near peak.
→ Optimal ~26 processes. With 32, pipeline flows continuously!
Efficiency >90%, throughput near peak.
⚙️ Based on 3GPP TR 38.821 §6.4.2 · Optimal HARQ processes ≈ RTT / TTI