πŸ“‘ MAC Layer TS 38.321

βš™οΈ Configure timers, pathloss thresholds; see triggering conditions and PHR procedure.

🧠 Concept & interactive simulation

πŸ“ Power Headroom Report (PHR) – full procedure ⏺️ real‑time animation

πŸ“˜ 3GPP references

πŸ“‹ LAB Configuration Guideline

1. How to configure:
- Set periodicPHR-Timer (slots) – PHR triggered when timer expires.
- Set prohibitPHR-Timer (slots) – prevents another PHR while running.
- Set dl-PathlossChange (dB) – threshold for pathloss change triggering.
- Choose PHR type (Single/Multiple cells) and Virtual PHR.
- Adjust cell parameters (P_CMAX, Tx power, pathloss).

2. What will be the flow:
- PHR is triggered by: periodic timer expiry, pathloss change > threshold, SCell activation, reconfiguration.
- When triggered, "PHR Triggered" flag is set.
- When UL grant arrives, PHR MAC CE is generated and sent; timers are restarted.
- prohibitPHR-Timer blocks further triggers while running.

3. What student can expect:
- Visual indicators: PHR triggered flag, timer values, pathloss changes.
- Power bars show P_CMAX, Tx power, and computed PH.
- MAC CE bytes appear when PHR is sent.
- Status updates in real time.

4. Recommended button sequence:
- First: Click Change Pathloss (PCell) to see pathloss change trigger.
- Then: Click Advance Timer repeatedly to see periodic timer expiry.
- Click Activate SCell to see activation trigger.
- Finally: Click UL Grant Arrives to send PHR and restart timers.
- Reset to start over.