5G RedCap: A Complete Beginner’s Guide to Lightweight 5G for IoT

5G RedCap (Reduced Capability), sometimes called NR-Light, is a new category of 5G device introduced in 3GPP Release 17.
It is designed to bridge the gap between low-power IoT technologies (like NB-IoT or LTE Cat-1) and high-performance 5G devices (like smartphones or industrial robots).

RedCap enables a lighter, lower-cost, lower-power version of 5G NR, optimized for IoT, wearables, industrial sensors, and mid-range devices that do not need gigabit speeds.

1. What Is 5G RedCap?

5G RedCap stands for Reduced Capability 5G NR, referring to devices that need:

• Moderate data rates

• Low device complexity

• Low power consumption

• Wide-area coverage

• Better latency than LTE

• Better reliability than NB-IoT

RedCap is built on the full 5G NR architecture but simplifies many physical and protocol layer components to reduce cost and device requirements.

It is not intended to replace ultra-high-speed 5G applications — instead, it fills the mid-range gap.

2. Why RedCap Was Created

Traditional IoT connectivity has three major categories:

RedCap solves the gap in the middle:

✔ Lower cost than full 5G
✔ Higher performance than NB-IoT
✔ Lower power than LTE
✔ Built on a future-proof 5G core network

3. 5G RedCap Technical Characteristics

Here are the primary technical capabilities that differentiate RedCap:

3.1 Data Rate

Typical RedCap throughput:

• Downlink: 50–150 Mbps

• Uplink: 10–50 Mbps

This is significantly lower than full 5G NR, but much higher than LTE Cat-1 or NB-IoT.

3.2 Reduced Spectrum & Antennas

RedCap uses:

• 20 MHz bandwidth (vs. 100 MHz for full 5G NR)

• 1 or 2 antennas (MIMO simplified)

• Fewer RF chains → lower power and cost

3.3 Reduced Complexity

RedCap removes:

• Ultra-wide bandwidth support

• 4x4 or 8x8 MIMO

• High-end modulation requirements

• Carrier aggregation (in most cases)

This dramatically reduces hardware cost.

3.4 Lower Power Usage

RedCap supports:

• Extended Discontinuous Reception (eDRX)

• Power Saving Mode (PSM)

• Network-triggered wake-up

This allows multi-year battery life, depending on application.

3.5 Latency

RedCap offers:

• 10–20 ms end-to-end latency

This improves over LTE and NB-IoT but is not as low as URLLC 5G.

4. 5G RedCap Architecture

RedCap uses the standard 5G NR architecture, including:

4.1 End Device (RedCap Module)

Typical forms:

• Industrial IoT modem

• Wearables chipset

• Smart meters

• Cameras

• Robotics sensors

Devices include simplified 5G NR hardware.

4.2 gNB (5G Base Station)

RedCap devices connect to the same 5G base stations as smartphones.

Enhancements include:

• Reduced UE capabilities

• Tailored physical channels

• Optimized scheduling for mid-tier devices

4.3 5G Core (5GC)

A fully cloud-native network:

• Network slicing

• Service-based architecture (SBA)

• Unified authentication and security

RedCap can be deployed on both SA (Standalone) and NSA (Non-Standalone) depending on the operator.

5. How RedCap Works (Simplified Flow)

1. Device collects data (sensor, video, meter, etc.)

2. RedCap module connects to 5G NR radio

3. gNB schedules reduced-bandwidth radio transmissions

4. Data is forwarded via the 5G Core

5. Application servers process and store the data

6. Optional downlink messages sent back (commands, updates, control)

6. 5G RedCap vs Other IoT Technologies

RedCap will likely replace LTE Cat-1, Cat-4 as operators refarm 4G spectrum to 5G.

7. Use Cases for 5G RedCap

RedCap is optimized for medium-bandwidth IoT and industrial applications.

Wearables

• Health trackers

• Smart watches

• AR/VR accessories

Industrial IoT

• Robotics sensors

• Manufacturing automation

• Machine-to-machine control

Smart Cities

• Video-enabled meters

• Environmental sensors

• Adaptive street lighting

Transportation

• V2X light communication

• Fleet monitoring

• Rail system sensors

Security & Cameras

• 720p / 1080p cameras

• Smart home surveillance

Healthcare

• Connected medical devices

• Remote patient monitoring

RedCap is ideal where NB-IoT is too slow, but full 5G is too expensive.

8. Advantages of 5G RedCap

• ✔ Lower device cost (compared to traditional 5G NR)

• ✔ Lower power consumption

• ✔ Higher data rates than LTE/NB-IoT

• ✔ Works on 5G networks and future-proof

• ✔ Supports mobility (unlike many LPWANs)

• ✔ Operator-grade security

• ✔ Supports 5G slicing and QoS control

9. Limitations of RedCap

• ✘ Not suitable for gigabit or high-end use cases

• ✘ More expensive than NB-IoT modules

• ✘ Requires 5G network availability

• ✘ Slightly higher power consumption vs NB-IoT