Imec, a world-leading research and innovation hub in nanoelectronics and digital technologies, presented a pioneering IEEE 802.15.4z compliant impulse radio (IR) ultra-wideband (UWB) transceiver for high-precision ranging at the VLSI Technology Symposium. Building on a cost-efficient silicon implementation, imec’s transceiver chip accomplishes a 1.4 mm ranging precision and comes with record low power consumption. As such, it paves the way for a variety of innovative (automotive) applications. One use case includes the creation of UWB radar-on-chip systems for in-cabin (child) presence detection, and driver monitoring.
IR-UWB technology is an enabler of multiple automotive, smart industry, smart home, and IoT use cases – thanks to its ranging and localization capabilities. It comes with the ability to locate assets in warehouses, hospitals, and factories with centimeter precision – and helps people navigate large spaces, like airports and shopping malls. One of IR-UWB’s main differentiators is that it largely outperforms narrowband technologies (such as Bluetooth) in terms of ranging precision. On the downside, it uses more complex and expensive circuits and typically exhibits higher power dissipation.
Imec’s UWB Transceiver Chip Combines Best-Ranging Precision with Lowest Power Consumption
“With the presentation of our UWB transceiver chip, imec overcomes yet another hurdle to UWB’s widespread adoption. Building on a cost-efficient silicon layout, the transceiver achieves the best-ranging precision with the lowest power consumption among state-of-the-art IEEE 802.15.4z radios,” stated Christian Bachmann, program director of wireless sensing at imec.
Fabricated in 28nm CMOS technology and occupying a silicon area of 1.33 mm, imec’s 6 to 9 GHz IEEE 802.15.4z compliant IR-UWB 3Rx-1Tx transceiver comes with a ranging precision down to 1.4 mm. While this outperforms competitive approaches by several orders of magnitude, it does not come at the expense of a larger power budget – as the transceiver chip merely consumes 8.7mW/21mW in continuous Tx/Rx mode. It also meets UWB’s tight international spectral emission regulations with sufficient margin.
The chip’s record low power consumption results from a highly optimized, low-power and interference-resilient Rx architecture, coupled with an innovative digital polar transmitter architecture. A distributed, two-stage all-digital PLL allows for further reduction of the chip’s power consumption and contributes to a reduced measurement time for localization. To improve its ranging performance (while complying with spectrum regulations), the system makes use of an analog finite impulse response (FIR)-based Tx pre-emphasis approach for more advanced, flexible pulse shaping.
Laying the Foundation of UWB Radar-on-Chip Systems
Christian Bachmann: “Imec is renowned for its pioneering research in the field of UWB technology. Recent achievements include the development of the world's first sub-5mW UWB transmitter chip for the IEEE 802.15.4z standard in 2021 and the unveiling of a UWB radio capable of supporting data rates of up to 1.66Gb/s (for high data rate, low-power applications) in 2022.”
“Yet, going forward, industry requires high-performance, low-power UWB transceivers that can support a multitude of use cases. So that is what we are presenting today. We believe this chip could ultimately support a whole new generation of UWB use cases, combining UWB ranging, communications and radar functionality. It is a technology that could find its way into automotive applications such as in-cabin presence detection, and driver monitoring – both of which stand or fall with the measurement accuracy and energy efficiency of the underlying technology,” he added.
To facilitate the commercialization of its technological breakthroughs, imec conducts its research in collaboration with a wide range of industrial partners. One of those partners in the UWB domain is CEVA, the leading licensor of wireless connectivity and smart sensing technologies.
“CEVA fully endorses imec’s belief in the massive potential of UWB in a wide variety of applications, including demanding automotive applications such as in-cabin radar for child presence detection. Teaming up with imec in the UWB realm enables us to offer a complete solution to accelerate the time to market for our joint customers, leading the way in the era of connected devices and smart industries,” added Tal Shalev, Vice President and General Manager, of the Wireless IoT BU at, CEVA. “CEVA’s UWB 802.15.4z modem plus CCC/FiRa MAC has low power, low latency and a high-precision ranging architecture that perfectly complements imec’s novel UWB transceiver”.
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