RedCap

Accelerating the future of Cellular IoT

5G RedCap device development requires reliable, high-performance communication with 5G networks, while maintaining the low power consumption and low cost demanded by IoT applications. Upon commercial deployment, interoperability with networks and carriers is essential. To ensure this, devices undergo 3GPP-based protocol and RF tests, the tests required by each country's regulations, as well as carrier certification tests.

This page introduces test solutions to address the challenges posed by the verification and certification processes of 5G RedCap device development.

What is 5G RedCap/eRedCap?

5G RedCap (Reduced Capability) is a 5G IoT technical specification defined in 3GPP Release 17 and intended for mid- to low-data-rate applications. RedCap supports peak download speeds of up to 150 Mbps while limiting UE bandwidth to 20 MHz and simplifying antenna configurations. eRedCap (enhanced RedCap) was added in Release 18 as a specification for IoT devices with a bandwidth limited to 5 MHz and a peak data rate of 10 Mbps, with a stronger focus on lower cost and lower power consumption. Unlike 4G cellular IoT technologies such as LTE-M and NB-IoT, RedCap and eRedCap offer millisecond-level low-latency communication. This capability positions RedCap and eRedCap as cellular IoT technologies well suited to a broader range of applications. RedCap and eRedCap target IoT scenarios including industrial sensors, equipment monitoring, surveillance cameras, wearable devices, and smart meters.

Consumer IoT

Wearables
XR glasses
Autonomous vehicles
Customer Premises Equipment (CPE)/Fixed Wireless Access (FWA)

Industrial IoT

Smart home
Smart city
Security cameras
Robots
Sensors

Low-end LTE replacement

Feature phones
Low-cost routers
Smart meters

Testing Challenges in RedCap Device Development

Developer performing iterative testing with a redcap device in the early development stage

Challenge 1: Improving the Efficiency of Iterative Testing in RedCap Development

During the development of RedCap devices, engineers must complete the validation required at each stage without making the test environment setup or the actual testing excessively burdensome. Typically, during device development, issues are rarely resolved within a single test iteration. Therefore, the time required for test preparation and execution becomes a critical factor affecting development speed. In the early stages of RedCap device development, test cycles are short, iterative, and focused on the key test items. This avoids excessive test overhead and keeps development on schedule.

Engineer developing a redcap device facing issues during regulatory testing and validation testing

Challenge 2: Insufficient Pre-Validation for Certification Testing

RedCap devices intended to operate in 5G cellular networks must undergo carrier certification and regulatory testing before they can be offered commercially. External organizations usually conduct these tests in the final stages of development. However, during certification testing, issues may be identified under conditions that were not fully anticipated during the development phase. This is often due to gaps between the range of radio environments and communication conditions validated during development and the much broader set of conditions used in certification testing. As a result, issues identified during certification testing may not be reproducible under in-house test conditions, necessitating extended root cause analysis and repeated validation cycles to bridge the gap between development and certification environments. In the later stages of RedCap device development, the challenge is to reproduce and validate the certification testing environments and conditions within the development process.

Test Solutions to Improve RedCap Device Development Efficiency

Solution 1: Enabling Efficient Iterative Testing Through the Virtualized Testing of Key Test Items

To address such challenges from the early stages of development, Anritsu provides the Virtual Signalling Tester MX844030PC (Virtual ST).

Virtual ST is a software-based test solution that runs protocol layers for RedCap in a virtual environment. It supports protocol testing, fundamental performance evaluation, and validation under stress conditions, which are critical in early- to mid-stage development. By focusing on the test items most frequently executed in RedCap development, Virtual ST enables flexible, rapid preparation of test environments and changes to test conditions. This makes it possible to repeatedly identify and isolate issues and verify fixes in short cycles. Virtual ST supports the early stages of RedCap device development as a test environment that is easy to introduce and supports design verification without interrupting iterative testing.

Radio communication test station for redcap test

Solution 2: Achieving Comprehensive Pre-Validation and Issue Reproduction for Certification Testing

To enhance pre-validation with certification testing in mind, Anritsu provides the Radio Communication Test Station MT8000A.

MT8000A is a comprehensive test platform that supports a wide range of tests, from protocol testing to RF testing, under RedCap conditions from the early stages of development through to preparation for certification testing. By reproducing the radio environments, network configurations, and communication conditions used in certification testing within a manufacturer's in-house environment, this enables pre-validation with broader test coverage and supports 3GPP-compliant RF and protocol testing. This allows manufacturers to respond more quickly to issues identified during certification testing and helps reduce the risk of delayed market introduction.