This paper demonstrates an IEEE 802.15.4z compliant Impulse Radio Ultra-Wideband (IR-UWB) radar system for in-cabin monitoring for automotive applications. The presented system demonstrates three in-cabin use cases running in real-time: occupancy detection, breathing rate estimation, and gesture detection. The IR-UWB radar system detects occupancy and estimates the breathing rates of persons sitting in a car's driver and/or front passenger seat. Furthermore, the radar system detects if the passenger is performing a pre-defined gesture. The experimental results demonstrate the effectiveness of the system in a real-time platform, confirming its potential for enhancing automotive safety and comfort. In the presented demo, we achieve a false alarm probability of lower than 10–3, a breathing rate accuracy of less than 1 beat per minute (bpm), and gesture detection accuracy of more than 90%.

Computation-in-Memory (CIM) is an emerging computing paradigm to address memory bottleneck challenges in computer architecture. A CIM unit cannot fully replace a general-purpose processor. Still, it significantly reduces the amount of data transfer between a traditional memory unit and the processor by enriching the transferred information. Data transactions between processor and memory consist of memory access addresses and values. While the main focus in the field of in-memory computing is to apply computations on the content of the memory (values), the importance of CPU-CIM address transactions and calculations for generating the sequence of access addresses for data-dominated applications is generally overlooked. However, the amount of information transactions used for “address” can easily be even more than half of the total transferred bits in many applications. In this article, we propose a circuit to perform the in-memory Address Calculation Accelerator. Our simulation results showed that calculating address sequences inside the memory (instead of the CPU) can significantly reduce the CPU-CIM address transactions and therefore contribute to considerable energy saving, latency, and bus traffic. For a chosen application of guided image filtering, in-memory address calculation results in almost two orders of magnitude reduction in address transactions over the memory bus.

A single-input and single-output (SISO) frequency-modulated continuous wave (FMCW) radar architecture is proposed and in vivo demonstrated for remote 2-D localization (range and angular information) and vital signs monitoring of multiple subjects. The radar sensor integrates two frequency scanning antennas which allow angular separation and enable determining a 2-D map (range versus angle) of a room environment from which people can be distinguished from objects and clutter. After technical tests to validate the functionality of the proposed architecture and data processing algorithm, a practical setup was successfully demonstrated to locate human volunteers, at different absolute distances and orientations, and to retrieve their respiratory and heart rate information. Experimental results show that this radar sensor can monitor accurately the vital signs of multiple subjects within typical room settings, reporting maximum mean absolute errors of 0.747 breaths-per-minute and 2.645 beats-per-minute, respectively, for respiration rate and heartbeat. Practical applications arise for Internet of Things (IoT), ambient-assisted living, healthcare, geriatric and quarantine medicine, automotive, rescue and security purposes.

A scalable low power Impulse Radio (IR) receiver baseband has been developed for an around-the-body audio streaming use case, supporting both coherent and non-coherent operation modes. With careful hardware/software co-optimization, the receiver algorithms are implemented using an Application-Specific-Instruction-set-Processor (ASIP) and several optimized hardware accelerators, allowing scalability and support of multi-mode operations in an energy-efficient manner. The receiver baseband is designed in a 90 nm standard CMOS process and is fully verified with the RF frontend. By using an all-digital parallel synchronization module, a short timing acquisition phase is realized, reducing synchronization overhead. In combination with a comprehensive set of low power measures, including hardware/software partitioning, parallelism, module level clock gating, multiple clock domains, operand isolation, multi voltage domains (MVD) and power gating techniques, an average power consumption of 5.6 mW for a 0.85 Mb/sec data rate mode is realized. This corresponds to 10.1pJ/bit for the coherent data processing of an 84 data bytes packet. Furthermore, the design is capable of processing 499.2 MSamples/sec at 840 mV.

A theoretical model for non-coherent start-of-frame-delimiter (SFD) detection in IEEE 802.15.4a is presented and closed form solutions for SFD threshold and signal-to-noise ratio (SNR) estimation are derived. The derived results are implemented in an impulse radio ultra wide band (IR-UWB) demonstrator operating in the 6-10.6 GHz UWB band. The demonstrator is designed for low power operation (in the mW range for combined digital base band (DBB) & radio frequency (RF)). The transmitter (TX) RF is duty cycled at pulse level and the receiver (RX) RF is switched to pulse level duty cycling when possible. Moreover, digital TX and RX resources are only switched on when needed. Measurement results are in close agreement with the derived closed form solutions.