Various medical systems exist for monitoring people in daily life, but they typically require the patient to wear a device, which can create discomfort and can limit long-term use. Contactless vital-sign monitoring would be preferable, but such technology is challenging to develop as it involves weak signals that need to be accurately detected within a practical distance, while being reliably distinguished from unwanted disturbance. Here, we show that a radar-based sensor can be used to monitor the individual vital signs (heartbeat and respiration) of multiple people in a real-world setting. The contactless approach, which does not require any body parts to be worn, uses two antennas (one transmitter and one receiver) and algorithms for target tracking and rejection of random body movements. As a result, it is robust against moderate random body movements (limb movements and desk work) and can keep track of individual people during vigorous movement (such as walking and standing up). A radar-based sensor can monitor the individual vital signs—heartbeat and respiration—of multiple people in a real-world setting, keeping track of individual people during vigorous movement.

Vital-sign monitoring and spatial tracking of multiple people using a contactless radar-based sensor

The application of ultra-wideband (UWB) technology to low-cost short-range communications presents unique challenges to the communications engineer. The impact of the US FCC's regulations and the characteristics of the low-power UWB propagation channels are explored, and their effects on UWB hardware design are illustrated. This tutorial introduction includes references to more detailed explorations of the subject.

Ultra-wideband radio

Ultra-wideband (UWB) technology is gaining increasing interest for its potential application to short-range indoor wireless communications Utilizing ultra-short pulses, UWB baseband transmissions enable rich multipath diversity, and can be demodulated with low complexity receivers Compliance with the FCC spectral mask, and interference avoidance to, and from, co-existing narrow-band services, calls for judicious design of UWB pulse shapers This paper introduces pulse shaper designs for UWB radios, which optimally utilize the bandwidth and power allowed by the FCC spectral mask The resulting baseband UWB systems can be either single-band, or, multi-band More important, the novel pulse shapers can support dynamic avoidance of narrow-band interference, as well as efficient implementation of fast frequency hopping, without invoking analog carriers

Designing optimal pulse-shapers for ultra-wideband radios

https://www.engr.colostate.edu/~lqyang/publist/jcn03dec_lyg.pdf

This paper has established a new theoretical framework that allows us to analyze the ultra-wideband system performance using the closed form formulations. A new generalized time-domain multipath channel based on the geometric theory of diffraction/uniform theory of diffraction (GTD/UTD) framework is incorporated into the system bit-error rate and signal-to-noise ratio by modifying the existing system model. Closed form expressions for important geometric configurations are derived in the time domain for the first time. Some interesting insights into the physical mechanisms and system analysis are observed through explicit expressions and numerical results.

A generalized time domain multipath channel and its application in ultra-wideband (UWB) wireless optimal receiver design-Part II: physics-based system analysis

Here, we present a description of a block scheme, characteristics, specific features of design and results of testing for a prototype of the ultrawideband (UWB) radar, which has been developed by Russian UWB group researchers at Moscow Aviation Institute at "analog and digital radio systems" department (www.uwbgroup.ru). The prototype was designed within a research work, which we are conducting on the state order from one of Russian federation state institutions. The UWB radar is intended for detection of moving targets at a distance of several kilometers. The radar design is divided into two stages. In the first stage, we have produced a radar prototype, which incorporates a low power narrow-pulse generator (NPG). During laboratory test, the prototype has afforded the detection of moving targets at the distance of up to one hundred meters. Thereby, the validity of technical solutions used for the whole radar's and radar unit's design was confirmed. In the second stage, we plan to conduct field tests of the radar prototype equipped with a high power NPG.

E. Ziganshin

Papers

Ultra-wideband radar