As their name suggests, telecommunications networks have been traditionally designed only for communications purposes, carrying voice traffic and different types of data used for communication. On the other hand, sensors, like radar, are treated as a different type of technology meaning different networks carried sensor-related data. While the principles of communication and sensing are long-established, they are on the verge of a large-scale shift as the integration of the two will be a landmark in the wireless evolution toward 6G.
Imagine what might be possible if your handheld cell phone was also a radar device. This technological evolution made possible by integrating sensing and communications would require innovations in the device itself and also in the network on which it operates.
Here we will explore the potential of what this new stage of evolution means.
Within the International Telecommunications Union (ITU)’s emerging vision for 6G, known as known as IMT-2030, integrated sensing and communications (ISAC) is expected to be a new, revolutionary feature of 6G, alongside integrated AI and communication and ubiquitous connectivity, and more foundational enhancements like mMTC, URLLC, and eMBB. The ITU’s vision is helping to guide industry groups and standards organizations, with 3GPP beginning to lay a foundation for this new technology capability in a Release 19 study item for the implementation of the pre-6G wireless standard, 5G Advanced. In fact, the European Telecommunications Standards Institute (ETSI) announced [https://portal.etsi.org/isac] the establishment of a new InterDigital-chaired industry specification group to focus on ISAC.
What is ISAC?
ISAC refers to the use of radio signals to “sense” or detect and identify various objects and surfaces within a surrounding environment. The radio network functions much like a radar, but in this scenario, it will be embedded into the network base station or user device instead of being an independent device with a distinct external data network.
The integration of sensing and communications will touch on nearly every aspect of system architecture, protocols, and radio access and will represent a major shift in the way communications systems and protocols are designed and implemented. Even today, industry is beginning to explore early ISAC in the telecommunications stack, focusing on system architecture, use cases, requirements, capabilities, and applications.
Historically, there have been early attempts to integrate sensing and communications, albeit in a more narrowly defined way. For example, some sensing capabilities were implemented in WLAN using the Wi-Fi signal, enabling a laptop with a Wi-Fi chip to be programmed to “wake up” when it sensed certain types of movement.
In 5G, industry began to use a 3GPP-standardized radio signal to achieve more accurate device positioning, which became a precursor to using radio signals for more sophisticated sensing.
Until recently, any sensing done using the communications network required the use of an external peripheral such as a LiDAR or a camera. The framework of the 3GPP standard assumed that sensing would be achieved using these external sources, but the shift toward ISAC will see the network become its own source of sensing. This evolution does not mean external sensors will become obsolete, but that the network and external sensors will complement each other.
Pre-standards groups like ETSI and its new ISAC ISG will do the important work to explore and forecast specific implementations of this technology, with each use case comprised of a mix of both external sensing and “internal” sensing done by the network itself. In one sensing scenario, there may be some object detection done by an external device capable of more accurately determining shape and characteristics, while the network monitors the detected object.
The massive amounts of data generated by external and network-based sensing will be made available to the network to enhance network operations or augment applications or services running on top of the network and is expected to empower greater network performance and application improvements.
Types of Sensing
As ISAC is implemented, a few different sensing types will proliferate.
One common type is monostatic sensing, like radar, meaning the transmitter is in the same node as the receiver, and it transmits a signal and receives the echo. Alternatively, bistatic sensing refers to scenarios where the transmitter and receiver are different. In this sensing type, the transmitter sends a signal, which hits and reflects off a target, after which another node picks up the echo from that object to complete the sensing. There are many other more complex sensing types, such as multi-static sensing, which involves multiple nodes.
It remains to be seen which sensing type will be the most prevalent type in 3GPP specifications, but it will most likely be a configuration that has minimal impact on network design and configuration. Bistatic sensing may be the most appropriate starting place because of the relatively straightforward ability to use the base station as the transmitter and the user device as a receiver, or vice-versa.
There are many exciting applications and use cases for this technology, many of which that will come into focus over time. For consumers, ISAC may help immersive media experiences like video conferencing become more realistic, because the user device will be capable of sensing more of the environment around the person you are conferencing with, supporting the creation of holographic images and more immersive interactions.
In an enterprise context, there are clear applications for use case like environmental monitoring, health monitoring, and intruder detection. Autonomous vehicles will also benefit greatly from the complementary nature of on-board and external sensing enabled by ISAC, alongside various cutting-edge connected enterprise use cases.
The ETSI ISAC ISG is excited to lead the exploration of these new opportunities and use cases, as well as the new infrastructure requirements to enable its success.
ISAC is a truly future technology and will not likely have backward compatibility constraints because the approach will require new signals introduced in 6G whose structures and numerologies aren’t part of the current 5G NR paradigm. ISAC will see its earliest standards considerations in 5G Advanced Release 19 introduced in early 2024 and throughout the development timeline for 6G.
3GPP has a mandate to help grow and mature this technology, in part because it revolutionizes the channel model, which historically consisted of a transmitter and a receiver. ISAC introduces a third node — the object to be sensed — which needs to be modeled within the 3GPP framework. This carries significant implications for the 3GPP channel model itself, and Release 19 will begin to address the early questions raised by this new technology.
Early working groups like ETSI’s ISAC ISG will explore critical security, privacy, and sustainability considerations around ISAC, ensuring that the technology empowers a host of new capabilities but also addresses any problems this new ecosystem might create. As inaugural chair of the ISAC ISG, I remain eager and excited to better understand and pioneer the potential for this new feature of our evolving wireless network into our 6G future.