Efforts toward Standardizing Ambient IoT Gain Pace, Promising More Attention in 2024

In December 2023, The 3rd Generation Partnership Project (3GPP) approved the inclusion of Ambient IoT as a Work Item in Release 19. The Work Item, entitled “Ambient Power-Enabled Internet of Things,” has as its objective “to specify 5G system requirements and KPIs in order to support ambient power enabled IoT services.” This marks the first time a standards body has gone beyond studies and looked to provide specifications supporting Ambient IoT. Accompanying this Work Item are a number of additional Study Items, including a “Study on Solutions for Ambient IoT in NR” and a “Study on Architecture Support of Ambient Power-Enabled IoT”—with the prospect for the latter to be converted to a Work Item in December 2024.

3GPP has been studying Ambient IoT for a number of years. In an early phase study on technical requirements of Ambient IoT, 3GPP considered Ambient IoT devices as “being either battery-less or with limited energy storage capability (i.e., using a capacitor) and the energy is provided through the harvesting of radio waves, light, motion, heat, or any other power source that could be seen suitable.” Devices may be passive (no energy storage), semi-passive (limited energy storage capacity and potential for amplification of backscattered energy) or active (limited energy storage capacity and active transmission radio).

The effort to include Ambient IoT in 3GPP standards has been driven by Wiliot over the past few years, as it looks to enhance ubiquitous support for its Pixel tags. These tags currently communicate using Bluetooth® Low Energy (LE) technology using dedicated energizing and backhaul infrastructure. Wiliot is also aiming to enable tags to be energized by Bluetooth® Radio Frequency (RF) waves from existing User Equipment (UE), such as speakers or smartphones, through a simple firmware update to the UE. The next step is to enable the tags to communicate over globally deployed cellular infrastructure. While Wiliot is one of the principal drivers of Ambient IoT standardization and one of the few companies today to describe itself as an Ambient IoT company, the potential impact is industry-wide and the technology is applicable in scenarios far outside its Pixel tags.

By virtue of being primarily powered by ambient energy, Ambient IoT devices are less reliant on mains or battery power, allowing smaller form factors, lower costs, and longer maintenance-free field life—contributing to the IoT, which is used pervasively. Ambient IoT today is primarily dominated by Bluetooth® technology by virtue of Bluetooth® LE’s very low power consumption, but this does not always have to be the case—and key standards bodies such as the IEEE and 3GPP, as well as the Bluetooth SIG, are studying feasibility and assessing what role they must play to make it possible for the broader ecosystem to build Ambient IoT devices.

Standardizing Ambient IoT is no easy task, and 3GPP’s “to-do” list is significant. 3GPP is assessing a variety of network topologies for Ambient IoT, using combinations of 3GPP base stations, intermediate nodes, assisting nodes, and UE devices acting in various capacities as energizers and backhaul equipment. For each topology, three of the technical challenges that 3GPP will face are:

• Network Registration and Management: Ubiquitous low-cost and low-security tags are a network operator nightmare. Devices currently connect to a cellular network through individual Subscriber Identity Modules (SIMs), but these may not be appropriate for low-cost and low-power Ambient IoT devices. A recent paper by 5G Americas, a trade association representing the interests of network operators, highlights some of the issues that will need to be overcome to facilitate network operator buy-in to the technology. Even when technology feasibility is established by 3GPP, it is a long haul to get the broader IoT ecosystem to pull together.
• Low-Power Protocols: Energy harvesting generates very small quantities of energy, usually measured in Microwatts (μW). Current low-power cellular protocols such as Narrowband Internet of Things (NB-IoT) are measured in Milliwatts (mW). This gap will need to be addressed by simplifying existing protocol stacks or by using multiple Radio Access Technologies (RATs) to get data onto 3GPP networks.
• Power Generation: This challenge involves creating the means for 3GPP equipment, whether base stations, smaller Access Points (APs), or UE such as smartphones, to energize Ambient IoT devices using RF signals. While Ambient IoT can be powered by other ambient energy sources, such as light or motion, standardization efforts across standards bodies are focused on harvesting energy from radio waves, particularly using backscattering techniques.

3GPP is looking to address many of these challenges, and more, in the scope of the Ambient IoT Work Item. The justification for the Work Item breaks the requirement for standards into functional requirements and performance requirements. Functional requirements relate to device capabilities and include issues such as communication aspects, positioning, device management, network capabilities, charging, and security. Performance requirements relate to service-level capabilities and include issues such as latency, service availability, data rate, message size, device density, communication range, and positioning accuracy.

The IEEE and the Bluetooth SIG are also looking more closely at Ambient IoT. In January 2024, the Bluetooth SIG released a research note setting out its stance on Ambient IoT and the work needed to broaden the technology’s adoption. Both the IEEE and the Bluetooth SIG are currently assessing use cases and technology feasibility with an eye on understanding how they can support their device maker ecosystems. Efforts will likely again focus around security and RF energy harvesting. Technical papers, study groups, and discussions with ecosystem members are increasing in frequency from both groups; this shows the will to get ahead of the technical challenges and facilitate homogeneous development of the technology, both to simplify the task for technology vendors and to ensure simplicity and interoperability for end users.

We are still at the start of the road for Ambient IoT. While the attention by standards bodies on Ambient IoT is a significant development of 2023, in particular, this will increase attention on the technology in 2024, and they are only one part of the puzzle. Some of the issues that will need to be addressed include:

• Interoperability of devices with existing network infrastructure
• Methods for deploying Ambient IoT tags and energizing at scale, and any security and privacy issues of doing so
• Development of off-the-shelf energy harvesting technologies—both those popular today (e.g., light or motion) and those receiving scrutiny (e.g., radio waves)
• Incentives and monetization strategies for very low-cost tags, at the device, network, and software levels.

Companies such as Wiliot and Paragon ID have been key in demonstrating capabilities and successful deployment strategies of IoT devices powered by ambient energy. As the number of device makers and solution providers grows, standardization will become increasingly important to support manufacturers and adopters alike. To ensure success of the technology both in the short and long terms, awareness and education of the broader ecosystem should be central to those pushing Ambient IoT. This should already involve discussions around incentives for different parts of the ecosystem to ensure deploying Ambient IoT solutions makes financial sense, rather than relying simply on the promise of low-cost hardware.