Why RedCap exists
The 5G modem cost curve presented a problem for IoT. Full 5G NR modems - capable of 256-QAM, 4x4 MIMO and 100 MHz bandwidth - were designed for smartphones and are expensive relative to IoT budgets. NB-IoT and LTE-M addressed the low end: battery-powered, very low data rate applications. But there was a gap in the middle: industrial IoT applications needing more than LTE-M but far less than a smartphone connection, where full 5G modem costs could not be justified.
RedCap fills that gap. It operates on the same 5G SA infrastructure as full 5G NR, benefits from network slicing and lower 5G core latency, but the modem itself is simpler, cheaper and more power-efficient.
RedCap capability reduction table
| Feature | Full 5G NR | 5G RedCap (Rel-17) | eRedCap (Rel-18) |
|---|---|---|---|
| Max downlink | Multi-Gbps | ~150 Mbps | ~50 Mbps |
| Max uplink | Multi-Gbps | ~50 Mbps | ~25 Mbps |
| Receive antennas | 4 | 2 | 1 |
| Bandwidth (FR1) | 100 MHz | 20 MHz | 5 or 10 MHz |
| Duplex | FDD and TDD | FDD and TDD | Half-duplex FDD |
| Power consumption | High | Medium | Low-medium |
| Target cost vs full 5G | Baseline | ~60-70% | ~40-50% |
RedCap use cases
The 3GPP design criteria for RedCap targeted three primary use cases: industrial wireless sensors (requiring low power and moderate data rates), video surveillance (requiring sustained uplink bandwidth above LTE-M capability), and wearable devices (requiring compact modem form factor). For UK IoT deployments, CCTV and industrial monitoring are the most immediately relevant applications.
Testing RedCap with CellTester
CellTester supports 5G RedCap signal testing on Teltonika routers with RedCap-capable modems. Signal metrics follow the same SS-RSRP, SS-RSRQ and SS-SINR framework as full 5G NR. The automated operator sweep includes RedCap registration where supported by UK operators.