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The arrival of 5G cellular technology was supposed to be the match that set the IoT world on fire, but it hasn’t exactly worked out that way. It’s not that the flames have been doused, but rather that IoT growth has smoldered instead of blazed.
5G itself has become widely deployed for a variety of use cases, but adoption has been slow for IoT-centric enterprise applications like health-related wearables, industrial IoT networks, surveillance and security, asset tracking and fleet management.
“In terms of latency and bandwidth, the vast majority of IoT devices do not need 5G,” says Jason Leigh, Research Manager, 5G & Mobility Research for IDC. “5G is like a Ferrari engine, but most cars don’t need a Ferrari engine.” The advanced capabilities of 5G also come at a price premium, and many IoT use cases cannot support the additional cost.
That could change, however, with a forthcoming 5G specification, dubbed RedCap, that is designed specifically for IoT devices. RedCap could be the spark that sets the IoT world ablaze.
What is RedCap?
The next generation of cellular technology is 5G Advanced or 5.5G. The spec is expected to be approved within a year. A key feature that will be included in 5G Advanced is a device category called “New Radio Reduced-Capability (RedCap) devices.”
RedCap includes a mix of capabilities that balance factors such as coverage and throughput with constraints such as limited battery life and a lack of antennas. The combination supports use cases that do not always need the high-performance capabilities of current 5G technology, but which would scale faster over advanced cellular networks.
“A major reason the adoption of 5G in the IoT space has been slow is because legacy technologies work just fine for many of these use cases,” Leigh says. If connectivity options like WiFi and legacy 3G LTE are working, there’s no real incentive to change, and while 3G has been phased out in the U.S., in much of the world it still dominates.
With RedCap, the hope is that IoT networks will benefit from the increasing scale of 5G deployments, which will make IoT feasible in a greater number of locations and for a greater number of devices. Since many constrained IoT devices will have fewer on-device capabilities, RedCap will make it easier for device manufacturers to prioritise things like low power consumption and ruggedisation.
What are the hurdles facing RedCap?
As carriers and telcos rushed to build out the first wave of 5G networks, they split 5G deployments into two categories: standalone (SA) and non-standalone (NSA). Today, the majority of 5G networks are NSA 5G, which are typically a mix of 5G radio access gear and 4G infrastructure.
However, as the specification stands now, it appears that RedCap will require operators to deploy 5G SA, which is still a minority of 5G deployments. According Global mobile Suppliers Association (GSA), 259 operators in 102 countries have launched commercial 5G services, but only 41 operators have launched or deployed public 5G SA networks, while 115 are included in a broader category that includes evaluating, testing, piloting and planning SA networks.
As 5G SA expansions steadily increase, RedCap promises to be an important bridge from legacy connectivity to standardised all-5G ecosystems.
RedCap testing is already underway
Even though 5.5G is still at least several months away from becoming an official specification, mobile vendors and operators aren’t waiting. They are already testing pre-5.5G devices, infrastructure, and networks.
AT&T, Ericsson, Nokia, and MediaTek have all been testing Advanced 5G. In July, AT&T tested 5G RedCap data calls in both its lab and from the field using their newly deployed 5G SA network. The test featured chipmaker MediaTek’s RedCap platform connecting to Nokia’s AirScale radio access gear, then onto AT&T’s 5G SA network core.
“5G RedCap is designed for devices currently served by LTE CAT-4 but provides equivalent or better in performance, with up to 150Mbps theoretical maximum downlink throughput. It helps reduce the complexity, cost and size of 5G devices. It also introduces options to allow devices to operate at lower power levels,” wrote Jason Sikes, AT&T’s AVP Device Architecture, in a company blog post about the RedCap test.
“These upgrades will bring 5G to products and applications full-featured 5G technologies are unable to serve like wearable devices such as smartwatches and AR glasses, as well as IoT devices for healthcare, asset tracking, smart home systems, fleet management and more.”
Another advantage of 5G RedCap will be its ability to provide connectivity to consumer wearable devices that are cost sensitive and space constrained. “A 5G RedCap core design has a maximum bandwidth of 20MHz with a single carrier, without the requirement to aggregate multiple carriers together. This allows for simpler and smaller antenna designs with one transmitter (1TX) and one or two receivers (1RX or 2RX) unlike the more complex MIMO antenna designs required for full feature 5G NR devices like smartphones,” Sikes noted.
MediaTek also worked with Ericsson to test data and Voice over New Radio (VoNR) calls on both TDD and FDD spectrum bands in an Ericsson lab in Sweden. (TDD uses one frequency band for both uplink and downlink, switching between the two. FDD uses different frequency bands for uplink and downlink.)
The test was intended to demonstrate the capability of Ericsson RedCap to serve as viable radio access network (RAN) software that will support 5.5G use cases for devices such as wearables, sensors, and industrial surveillance cameras that require consistent connectivity that doesn’t quickly drain the devices’ batteries.
“The Ericsson Reduced Capability software will open up a whole new world of possibilities for new types of devices that do not require the full range of 5G performance, and these FDD and TDD calls are a crucial first milestone on that journey,” said Sibel Tombaz, Head of Product Line 5G RAN at Ericsson. “By enabling both data and Voice over New Radio (VoNR) on the FDD and TDD spectrum bands, Ericsson RedCap is pioneering a whole new range of use cases for both consumers and industries in ways that are both cost- and energy-efficient.”
Using pre-commercial Ericsson RedCap software and MediaTek’s RedCap testing platform, the test involved an FDD data call, which achieved a throughput speed of 220 Mbps for downlink and 74 Mbps for uplink. The mobile partners also placed a TDD data call that reached a downlink speed of 153 Mbps and uplink speed of 13.5Mbps.
These speeds are enough to support a range of IoT use cases, including consumer wearables and industrial sensors. Ericsson intends to have a pre-specification RedCap ecosystem ready commercially by November, delivering it as a software addition to their existing 5G SA networks.
Is RedCap a necessary step towards 6G?
A big advantage of 5.5G is that it can be deployed as a software upgrade. “One thing the industry really did right with the early 5G deployments was design them to be upgraded through software patches,” Leigh says. In theory, this means that 5.5G could accommodate legacy LTE infrastructure, and some measure of backwards-compatibility could be included to accommodate legacy devices.
The wearables most people think about tend to be the ones we already use, such as smart watches. With better connectivity in lower-cost devices, however, RedCap will enable such use cases as sensors embedded in ID tags or even hard hats for geofencing.
The advantage of RedCap versus RFID and WiFi is that the device won’t lose connectivity if it leaves the facility, but in most cases today, adding cellular is cost prohibitive. Moreover, adding cellular means adding an extra antenna and an upgraded battery.
Experts see the ability to pull in constrained devices as a necessary step on the way to an all-5G ecosystem, but it’s probably more realistic that this level of pervasiveness will come with 6G.
“Spectrum is the life blood of the industry, and if we start talking about 6G, where will that spectrum come from?” Leigh asked. 6G spectrum will most likely come from shutting down legacy cellular connections. “We’re talking about sunsetting LTE worldwide, but in the U.S., it was painful to shut 3G down. RedCap is a necessary part of the long-term migration to a common mobile ecosystem.”
Today, IoT devices have a variety of ways to connect, WiFi, LPWAN, Bluetooth, LTE and 5G. This may look like abundance, and something that gives manufacturers and customers bountiful choices, but the reality is that a fractured market with poor interoperability has resulted in slower than expected growth.
RedCap could start to change that, prompting operators to speed up their upgrades to 5G SA and then 5.5G, so they can serve customers who need a more affordable version of 5G to make their IoT use cases viable at scale.
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(Jeff Vance is an IDG contributing writer and the founder of Startup50.com, a site that discovers, analyses, and ranks tech startups.)
