RRC Capacity Calculator
Calculate RRC-Connected utilization and maximum subscriber capacity for LTE eNB and 5G gNB networks. Includes RRC-Inactive context for 5G NR.
Technology
Total cells = sites × sectors
Typical LTE: 1 200–5 000
% with active data/voice at peak
Design threshold — typically 80%
RRC-Connected Utilization
30,000 connected / 360,000 max
Max RRC-Connected capacity
300 cells × 1200 per cell
Current simultaneous connections
150000 subscribers × 20% active
Available headroom
Additional connections before reaching max
Max subscribers at 80% target
Recommended subscriber ceiling
RRC States & Capacity
RRC (Radio Resource Control) manages the connection between a UE and the base station. Each cell has a finite number of simultaneous RRC contexts it can maintain.
| State | Technology | Typical limit/cell | Description |
|---|---|---|---|
| RRC-Connected | 4G & 5G | 1 200–5 000 (LTE) 3 000–10 000 (NR) | Active data or voice; full context held at eNB/gNB |
| RRC-Idle | 4G & 5G | Unlimited | No context in RAN; paged on incoming data |
| RRC-Inactive | 5G NR only | ~2× Connected | Suspended context kept at gNB; fast resume without full re-attach |
To estimate total subscriber capacity including overbooking, use the subscriber capacity calculator.
Frequently Asked Questions
What is RRC in LTE and 5G?▾
RRC (Radio Resource Control) is the protocol layer that manages the connection between a User Equipment (UE) and the base station (eNB in LTE, gNB in 5G NR). It controls connection establishment, reconfiguration, handover, and release. Each cell can maintain a finite number of simultaneous RRC contexts — this limit is the primary constraint on how many users can be actively served at once.
What is RRC-Inactive in 5G NR?▾
RRC-Inactive is a new UE state introduced in 5G NR that sits between RRC-Connected and RRC-Idle. The UE suspends its RRC connection but the gNB retains the UE context (security keys, RLC/PDCP state). This allows very fast connection resume without a full re-establishment procedure, saving both signaling overhead and battery life. The gNB can typically maintain approximately twice as many Inactive contexts as Connected contexts simultaneously.
What is a good RRC utilization target?▾
A healthy RRC utilization target is 60–70% of the cell's maximum RRC-Connected capacity during the busy hour. Staying below 70% leaves headroom for traffic bursts, handover traffic, and seasonal peaks without causing congestion. When utilization consistently exceeds 80%, it is a strong indicator that additional capacity (new sites, additional carriers, or small cells) is needed.
How does RRC capacity affect total subscriber count?▾
RRC capacity directly sets the ceiling on simultaneous active users per cell. Dividing total RRC capacity across the network by the busy-hour active ratio gives the maximum subscriber count. For example, 1 000 cells × 1 200 RRC/cell = 1.2 M simultaneous connections. At 20% active ratio with 8:1 overbooking, this supports up to 48 M subscribers. Use the Subscriber Capacity calculator to run this end-to-end dimensioning.