5G RedCap, completing the 3GPP puzzle and beyond

One of the most exciting parts of completing a puzzle is the moment you are about to figure out what a section of the picture looks like. Let us say you have connected some pieces but are left with that classic space right in the middle. You are searching, but it takes time for you to find the piece that comes to complete a semi-finished image. Once you finally do it, the picture takes more shape, enabling you to move forward to fill in the remaining pieces.

5G RedCap (also known as NR Light) is much like this missing puzzle piece, helping complete the available pathways to 5G for IoT applications. For example, suppose you are an IoT developer or device maker, especially those requiring medium data rates. In that case, you might have had a nagging feeling that something was missing when 3GPP published the original Release 15 set of 5G specifications. Perhaps you spotted it immediately, a missing transition path to 5G for applications currently utilizing LTE Cat 1 or Cat 4 air interfaces.

Devices relying on 4G LTE technology will need to migrate to 5G in the coming decade. Taking this into account, RedCap fills an essential gap under the 5G umbrella. Further discussion should focus on the 5G puzzle pieces accelerating the transition for specific use cases and the factors influencing a successful migration of IoT applications to 5G networks. 5G technology offers additional capabilities full of nuances beyond data rates. Hence, industries and businesses must ponder them before selecting the most suitable pathway for their solutions.

Current use cases and scope

The 5G specification established three initial use cases: eMBB (enhanced Mobile Broadband), uRLLC (ultra-Reliable Low Latency Communication), and mMTC (massive Machine Type Communication). eMBB provides higher data rates and improved latency. uRLLC delivers the lowest possible latency, the highest network reliability, and a robust security level, whereas mMTC offers ultra-low power consumption and enhanced in-building coverage.

Each technology, designed to address specific market segments, provides extensive possibilities to its users. Still, a gap remained for some IoT and consumer applications in areas such as industrial monitoring and control, telematics, video surveillance, sensor networks, and wearables.

What is 5G RedCap or NR Light?

When 3GPP published a new specification through its Release 17 in 2022, it introduced RedCap to fill the gap. The 5G Reduced Capability (RedCap) design, alternatively named NR Light, encompasses various requirements. Improvements in data rate, device complexity, band support, and power consumption made RedCap suitable for applications connecting via LTE Cat 1 or Cat 4. Based on mobile network operator rollout plans and chipset availability, the earliest commercial RedCap devices should reach the market in 2024.

Reducing capabilities equals reducing complexity. Comparing the capabilities of Rel 17 RedCap versus Rel 15 eMBB devices, five relevant reductions stand out: maximum bandwidth, device receive antennas, maximum number of downlink (DL) MIMO layers, maximum downlink modulation order, and duplex operation. When comparing RedCap with LTE Cat 1 or Cat 4, the main benefits concern peak data rate, which can be higher, lower latency than LTE Cat 4, and power consumption improvements.

3GPP Release 18 encompasses further evolution of 5G RedCap, targeted for completion in Q1 2024. This includes more complexity reductions that should expand the RedCap spec, bringing it closer to LTE Cat 1 capabilities. However, considering network availability and chipsets after 3GPP publishes a new release, the go-to-market for Rel 18 based devices will likely happen until 2028.

5G RedCap use cases

RedCap, as specified in 3GPP Rel 17, covers use cases with higher data rate requirements than LTE-M or NB-IoT and lower power consumption and device size than eMBB. A range of use cases will benefit from RedCap, including wearables, video monitoring/surveillance, industrial monitoring, and telematics. Smartwatches and other wearables must support high data rates in small form factors with relatively low power consumption, which is not achievable with eMBB or mMTC. Many video applications for smart cities, home security, and even smart factory use cases do not require the high data rates eMBB offers, thus benefiting from the smaller form factors and lower power consumption achievable with 5G RedCap. Telematics applications, currently connecting via LTE Cat 1 and Cat 4, are also good candidates for RedCap.

When to migrate from LTE Cat 1 or Cat 4 to 5G RedCap depends on the application, planned lifecycle, and targeted geographic region for deployment. Likely, mobile network operators in the United States and some APAC countries will be the first to roll out RedCap, prompting an earlier transition phase and an eventual lifecycle end for LTE networks. Long lifecycle applications, such as those with planned deployments of ten years or more, would also benefit from evaluating a transition to 5G RedCap sooner rather than later.

Before you go

Designing a device based on connectivity technology is always challenging in a transition period. Industries, private and public companies, governments, and municipalities are all searching for the best choice according to their needs. Making this choice is more complex than going to the supermarket and picking your favorite ice cream among the various flavors in front of you.

Whoever participates in this decision must consider feature trade-offs, timing, and opportunity costs. And factors such as efficiency, convenience, and longevity certainly have more impact than choosing an ice cream flavor. Moreover, designing a device supported by specific technology affects not only its capabilities but also how to monetize it and its profitability over the lifecycle. The question thus remains, does this new puzzle piece adapt to the needs of your business?