Wideband Technology for Medical Detection and Monitoring

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Transmit only UWB body area network for medical applications

This paper investigates methods to enhance the reliability of an ultra-wideband transmit-only (UWB Tx-only) sensor system. UWB Tx-only system uses asynchronous burst transmission, where each individual sensor transmits periodically without prior knowledge of other users and the channel condition. The application of UWB Tx-only sensor system for wireless body area network (WBAN) in a single user and multiple user environments is presented. In a single user environment, the main source of interference is from the collision of transmitted signals from individual sensors on the body. In a multiple user scenario, apart from the interference due to collision, there is also another source of interference from transmitting sensors of nearby users. The two major factors affecting the system reliability are the signal to noise ratio and the probability of collisions. The signal to noise ratio can be enhanced with a higher transmission power, which can be achieved through the use of gated systems and by carefully optimizing the pulse repetitive frequency and the gating duty cycle when generating an UWB transmission signal. Meanwhile the collision probability in a Tx-only UWB WBAN system can be reduced by arranging unique transmission intervals. It is shown in this paper that the collision probability for the case of burst transmission can be reduced to less than twice that of a pulse transmission through careful selection of the transmission interval

Real-Time Performance of a Self-Powered Environmental IoT Sensor Network System

Wireless sensor networks (WSNs) play an increasingly important role in monitoring applications in many areas. With the emergence of the Internet-of-Things (IoT), many more lowpower sensors will need to be deployed in various environments to collect and monitor data about environmental factors in real time. Providing power supply to these sensor nodes becomes a critical challenge for realizations of IoT applications as sensor nodes are normally battery-powered and have a limited lifetime. This paper proposes a wireless sensor network that is powered by solar energy harvesting. The sensor network monitors the environmental data with low-power sensor electronics and forms a network using multiple XBee wireless modules. A detailed performance analysis of the network system under solar energy harvesting has been presented. The sensor network system and the proposed energy-harvesting techniques are configured to achieve a continuous energy source for the sensor network. The proposed energy-harvesting system has been successfully designed to enable an energy solution in order to keep sensor nodes active and reliable for a whole day. The paper also outlines some of our experiences in real-time implementation of a sensor network system with energy harvesting

Ultra Wideband Wireless Body Area Networks

X, 173 p. 104 illus., 70 illus. in color.online r

An Internet-of-Things (IoT) Network System for Connected Safety and Health Monitoring Applications

This paper presents a hybrid wearable sensor network system towards the Internet of Things (IoT) connected safety and health monitoring applications. The system is aimed at improving safety in the outdoor workplace. The proposed system consists of a wearable body area network (WBAN) to collect user data and a low-power wide-area network (LPWAN) to connect the WBAN with the Internet. The wearable sensors in the WBAN are exerted to measure the environmental conditions around the subject using a Safe Node and monitor the vital signs of the subject using a Health Node. A standalone local server (gateway), which can process the raw sensor signals, display the environmental and physiological data, and trigger an alert if any emergency circumstance is detected, is designed within the proposed network. To connect the gateway with the Internet, an IoT cloud server is implemented to provide more functionalities, such as web monitoring and mobile applications

A non-coherent DPSK data receiver with interference cancellation for dual-band transcutaneous telemetries

A dual-band telemetry, which has different carrier frequencies for power and data signals, is used to maximize both power transfer efficiency and data rate for transcutaneous implants. However, in such a system, the power signal interferes with the data transmission due to the multiple magnetic couplings paths within the inductive coils. Since the power level of the transmitted power signal is significantly larger than that of the data signal, it usually requires a high-order filter to suppress the interference. This paper presents a non-coherent DPSK receiver without a high-order filter that is robust to the interference caused by the power carrier signal. The proposed scheme uses differential demodulation in the analog domain to cancel the interference signal for a dual-band configuration. The data demodulation also uses subsampling to avoid carrier synchronization circuits such as PLLs. The experimental results show that the demodulator can recover 1 and 2 Mb/s data rates at a 20 MHz carrier frequency, and it is able to cancel an interference signal that is 12 dB larger than the data signal without using complex filters. The demodulator is fabricated in a 0.35 μm CMOS process, with a power consumption of 6.2 mW and an active die area of 2.6 X 1.7mm²

A doppler radar system for sensing physiological parameters in walking and standing positions

Doppler radar can be implemented for sensing physiological parameters wirelessly at a distance. Detecting respiration rate, an important human body parameter, is essential in a range of applications like emergency and military healthcare environments, and Doppler radar records actual chest motion. One challenge in using Doppler radar is being able to monitor several patients simultaneously and in different situations like standing, walking, or lying. This paper presents a complete transmitter-receiver Doppler radar system, which uses a 4 GHz continuous wave radar signal transmission and receiving system, to extract base-band data from a phase-shifted signal. This work reports experimental evaluations of the system for one and two subjects in various standing and walking positions. It provides a detailed signal analysis of various breathing rates of these two subjects simultaneously. These results will be useful in future medical monitoring applications