For us consumers, 5G refers to higher (mobile phone) performance, higher resolution video, faster mobile game speed, and more ways to meet the needs of our consumers. But the real promise of 5G is to serve many vertical non-mobile markets. This is also an area where mobile network operators and the entire ecosystem are looking to monetize huge investments in 5G network infrastructure. The expected 5G effect of the IoT revolution is to expand mobile networks to billions of IoT nodes. This is an ambitious goal, as 5G, in addition to the explosive growth of mobile network scale, must also accommodate the diversity of these network endpoints (hereafter referred to as “things”). The things mentioned here range from mobile phones and “frequently running” fixed wireless networks that require a lot of bandwidth, to sensors that only need to transmit or receive small data packets infrequently. It’s no surprise that many IoT products fall somewhere in between. They don’t need full eMBB (Enhanced Mobile Broadband) 5G performance, but their power/cost expectations are more stringent than smartphones or fixed terminals, and they require extremely low latency in a variety of applications. That’s where the new 5G RedCap standard comes in.

3GPP broadband standards have developed in 4 different (but related) directions (see chart below). Since version 15, the first and main direction is eMBB, targeting consumer mobile phones and fixed wireless access (FWA). As of version 16, the second direction is low-latency URLLC, targeting time-critical edge computing and enabling future AR/VR devices. The third direction is Sidelink, which is primarily geared towards automotive V2X, but is not expected to support non-automotive use cases until release 18, covering the industrial and IoT domains (which will converge with RedCap). The fourth direction is IoT 5G. LTE (especially LTE Cat-1) currently offers some services, but with the introduction of 5G RedCap in Release 17, 5G has now fully taken over these services and is expected to be further improved and optimized in Release 18.

Figure 1 Evolution of 5G broadband standards

What is RedCap?

RedCap simply means reducing capacity. All the benefits of 5G, especially in the network, are comparable in performance to previous generation LTE, but with significantly lower latency, mainly for the lack of performance between baseline full-performance 5G devices (peak rates in the Gbps range) that support eMBB and URLLC grade, and narrow bandwidth MMTC (supports only 1Mbps). RedCap devices will support performance levels of approximately 85 Mbps and can be used for a variety of industrial and IoT use cases.

But what are the benefits of using 5G if the speed is not fully utilized? The benefits are many. Supporting IoT over 5G networks enables cost-effective greenfield deployments (no need to support 3 networks: 5G, LTE and eMTC/NB-IoT). It’s no coincidence that 5G’s focus on reduced-capacity use cases coincides with the rapid pace of growth in private networks in terms of infrastructure. The combination of the two opens up the field for new and cost-effective deployment methods to solve enterprise and industrial application challenges. 5G networks also offer more spectrum options, including unlicensed spectrum. RedCap will also support mmWave operation if limited coverage can play an advantage in spectrum reuse. 5G networks utilize advanced beamforming techniques (the complexity lies in the infrastructure) and can also provide wider coverage in the sub-6GHz range, making customer premises equipment leaner, more compact and energy efficient.

5G can also improve device positioning and is expected to achieve centimeter-level positioning accuracy in the upcoming 17th release, further facilitating industrial applications.

5G networks also offer better network management than LTE, supporting guaranteed quality of service (QoS), for example in terms of security.

This enhanced management can be provided within a common network infrastructure through software-based network slicing, security, and mobile edge computing (MEC) options. Network slicing can provide multi-level QoS without adding more network hardware costs and reuse the same network infrastructure to support highly distributed industrial applications. MEC migrates traditional cloud computing functions into the network to reduce congestion, increase costs, and reduce latency. For example, security and artificial intelligence functions can be provided in the local gateway. Private cellular networks are another possible application where ultra-high performance may not be as important as the benefits of enhanced security, improved availability, extended coverage, and slicing options based on the needs of the network.

What types of IoT applications can benefit from these enhancements? Industrial sensors in factories and grids (e.g. pressure, CO2, humidity, motion, temperature sensors, etc.), monitoring monitors, wearables (including emerging XR devices, especially in the form of glasses), telematics systems, Electronic health and medical monitoring equipment. The information they share or must respond to has some degree of criticality. However, all of the above applications are very cost and power sensitive in the market. RedCap is designed to help IoT product manufacturers find the right balance for their needs.

Car telemetry is a specific example. We typically consider cellular applications in V2X vehicles, either vehicles communicating with other vehicles or infrastructure, or infrastructure for safety, navigation, traffic management. This requires dedicated support for Side-link communications, as well as 5G Redcap-like performance. Telemetry is a very different application. A vehicle-to-everything communication box (T-Box) is a mature electronic device in modern cars that is responsible for remotely connecting vehicle functions and more. These systems use cellular technology, while emerging systems are starting to use 5G. In this type of application, the IoV box can handle over-the-air updates, collect and communicate vehicle statistics, and schedule service when problems are detected. It is estimated that the number of long-range communication links will exceed V2X, well within the Redcap performance envelope.

So how do we keep up with RedCap?

That sounds good, but RedCap is not yet fully approved; approval is expected in mid-2022. We expect an initial deployment of RedCap between 2024-2025, with a surge in users after 2026. But does this mean that when RedCap goes live, the communication function has to be completely replaced? If so, this change can be costly to schedule and development costs. It is recommended that you build your product with a communication system that can both run in LTE and easily switch to RedCap-enabled via a software update or a simple derivative. Many product manufacturers are eager to find such a solution, a communication link that can help them smoothly migrate to 5G RedCap once the standard matures, so that products can hit the shelves tomorrow. Planning for the next generation without compromising short-term earnings is always risky, but that risk should be manageable. As IoT applications require low cost, we expect RedCap implementations to be more integrated, not only with the digital baseband and RF parts, but in some cases with other complementary communication technologies and application-specific SoCs. This will allow SoCs to be optimized for specific applications and provide options for new suppliers and original equipment manufacturers (OEMs) not specializing in communications to differentiate by integrating RedCap IP into the SoC. Similar to what they are doing with WiFi now.

Reviewing Editor: Peng Jing

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