Backhaul Capacity Calculator
Dimension per-sector and aggregate backhaul bandwidth for LTE and 5G NR base station sites. Accounts for busy-hour factor, protocol overhead, and link redundancy.
Typical: 3 (tri-sector); up to 6 for split-sector sites
Peak DL Mbps per sector (cell edge to peak: 50–400 Mbps)
UL = 25%. FDD: use 50%. TDD typical: 70–80%.
Fraction of peak throughput sustained in busy hour (typ. 60–80%)
GTP-U + UDP + IP + Ethernet headers (typ. 7–10%)
N+1 — standard commercial deployment
Standard microwave supports up to ~500 Mbps–1 Gbps per link. Multi-link aggregation needed for high-throughput 5G sites.
Per-sector backhaul (DL)
Peak 100 Mbps × 70% BH × (1 + 8% overhead)
Site total — Downlink
Per-sector 75.6 Mbps × 3 sectors
Site total — Uplink
DL × (25% UL / 75% DL)
Aggregate (DL + UL)
Total bidirectional site throughput
With redundancy (N+1 — 2×)
Aggregate × redundancy factor
CIR — Committed Information Rate
80% of aggregate — guaranteed minimum bandwidth for SLA
PIR — Peak Information Rate
Full redundant capacity — maximum burst rate
Backhaul Dimensioning Reference
Backhaul capacity must be planned to handle the busy-hour peak with headroom for bursts and link failures. For Open RAN fronthaul dimensioning or core network signaling load planning, see the dedicated calculators.
Calculation formulas
Per-sector BH (Mbps) = Peak × BH% × (1 + overhead%)
Site DL = Per-sector × sectors
Site UL = Site DL × (UL% / DL%)
Aggregate = Site DL + Site UL
With redundancy = Aggregate × redundancy_factor
CIR recommendation = Aggregate × 0.80
Redundancy models
| Redundancy model | Multiplier | Use case |
|---|---|---|
| None | 1× | Lab / test sites |
| N+1 | 2× | Standard commercial sites |
| N+2 | 3× | Critical / hub sites |
Link capacity tiers
| Tier | Capacity | Technology |
|---|---|---|
| Low | < 100 Mbps | E1/T1 bundle, sub-6 GHz MW |
| Standard | 100–500 Mbps | Microwave (6–42 GHz) |
| High | 500 Mbps–2 Gbps | High-cap MW, E-band (70/80 GHz) |
| Fiber | > 2 Gbps | Optical fiber, DWDM |
Frequently Asked Questions
What is backhaul in mobile networks?▾
Backhaul is the transport link between a base station (eNB in 4G, gNB in 5G) and the mobile core network (EPC or 5GC). It carries all user-plane data (GTP-U tunnels) and control-plane signalling (S1-AP in 4G, NG-AP in 5G). Backhaul capacity directly limits the maximum throughput a site can deliver to end users.
How is per-site backhaul bandwidth calculated?▾
Required backhaul = sectors × peak_sector_throughput × busy_hour_factor × (1 + overhead%). The overhead factor (typically 7–10%) accounts for GTP-U, IP, UDP, and Ethernet encapsulation headers added on top of user payload. A 70% busy-hour factor converts peak rate to the sustained rate the link must handle during the peak hour.
What is the difference between CIR and PIR in backhaul?▾
CIR (Committed Information Rate) is the guaranteed minimum bandwidth a backhaul link must always deliver — typically dimensioned at 70–80% of the calculated aggregate capacity. PIR (Peak Information Rate) is the maximum burst rate the link allows, equal to the full redundant capacity. SLA contracts between operators and backhaul providers are written in CIR/PIR terms.
When should I use microwave vs fiber backhaul?▾
Fiber backhaul offers virtually unlimited capacity and low latency but requires civil works and may not be available at all sites. Microwave is deployable in weeks and typically supports up to 1–2 Gbps per link (or higher with aggregation and mmWave). For 5G sites with massive MIMO and carrier aggregation, aggregate throughput can exceed 2–4 Gbps, often requiring fiber or multi-link microwave aggregation.