Strategy Framework (Targets)
- PRB Load ≤ 80% (Day Average)
- PRB Load ≤ 85% (Busy Hour)
- User DL Throughput ≥ 10 Mbps
- 4CC Carrier Aggregation (10+20+20+5 MHz)
- All features already enabled (MLB, CA, 256QAM, CoMP, RIM, etc.)
Capacity Dimensioning (Math Check First)
- Total bandwidth: 55 MHz (B1 10 + B3 20 + B7 20 + B8 5)
- LTE spectral efficiency: ~6–7 bps/Hz
- Theoretical DL capacity: ~330 Mbps (~250 Mbps realistically usable)
- If each user needs 10 Mbps → ~25 active users per sector (sustainable under 80% PRB)
PRB Control Strategy (Most Important)
A. Band Prioritization
- High-capacity bands (B3 + B7 – 40 MHz) → Set as Primary PCell priority
- Low bands (B8 + B1) → Keep mainly for coverage users
B. Admission Control Optimization
- Max PRB admission threshold: 75%
- ERAB setup reject threshold: 80%
- CA activation: RSRP > -105 dBm
- 256QAM activation: SINR > 15 dB
MLB (Mobility Load Balancing) Tuning
- Trigger MLB at 70% PRB
- Increase CIO toward low-load neighbors
- Enable dynamic A3 offset adjustment
- Activate load-based handover (not only RSRP-based)
Carrier Aggregation Optimization
- Inter-band CA priority:
B3+B7 (highest) → B3+B1 → B7+B1 → B3+B8 (edge only) - CA activation threshold: RSRP > -105 dBm, SINR > 10 dB
Edge User Control (Critical)
- Apply RIM optimization and ICIC/eICIC tuning
- Optimize antenna tilt
- Target: Edge users < 20% of total users
Throughput Guarantee Strategy (≥10 Mbps)
- Scheduler: Proportional Fair with throughput bias
- Activate Turbo Start for video traffic only
- Ensure 4x4 MIMO on B3/B7
- 256QAM usage target: >25% of DL traffic
Practical PRB Reduction Actions (If Still High)
If PRB >85% during Busy Hour:
- Increase CIO
- Reduce cell range
- Reduce DL power
- Limit maximum UEs per sector
When Expansion Is Required
If PRB remains >85% and active users >30 per sector:
- Add small cells
- Perform sector split
- Add 5G NSA anchor
- Add an additional 20 MHz carrier
Practical KPI Monitoring Table
- PRB DL (Day Avg) < 80%
- PRB DL (Busy Hour) < 85%
- Avg User DL Throughput > 10 Mbps
- CA Usage > 60%
- 256QAM Ratio > 25%
- Cell Edge Users < 20%
- HO Success Rate > 98%
Final Real-World Strategy
Control edge users + trigger MLB early + ensure proper CA activation + strongly prioritize high bands
= Stable PRB below 80% and sustainable throughput performance 