Chiung-An Chen

Wireless Body Sensor Network With Adaptive Low-Power Design for Biometrics and Healthcare Applications

A four-levels hierarchical wireless body sensor network (WBSN) system is designed for biometrics and healthcare applications. It also separates pathways for communication and control. In order to improve performance, a communication cycle is constructed for synchronizing the WBSN system with the pipeline. A low-power adaptive process is a necessity for long-time healthcare monitoring. It includes a data encoder and an adaptive power conserving algorithm within each sensor node along with an accurate control switch system for adaptive power control. The thermal sensor node consists of a micro control unit (MCU), a thermal bipolar junction transistor sensor, an analog-to-digital converter (ADC), a calibrator, a data encoder, a 2.4-GHz radio frequency transceiver, and an antenna. When detecting ten body temperature or 240 electrocardiogram (ECG) signals per second, the power consumption is either 106.3 ¿W or 220.4 ¿W. By switching circuits, multi sharing wireless protocol, and reducing transmission data by data encoder, it achieves a reduction of 99.573% or 99.164% in power consumption compared to those without using adaptive and encoding modules. Compared with published research reports and industrial works, the proposed method is 69.6% or 98% lower than the power consumption in thermal sensor nodes which consist only of a sensor and ADC (without MCU, 2.4-GHz transceiver, modulator, demodulator, and data encoder) or wireless ECG sensor nodes which selected Bluetooth, 2.4-GHz transceiver, and Zigbee as wireless protocols.

A Wireless Body Sensor Network System for Healthcare Monitoring Application

A four levels hierarchy wireless body sensor network (WBSN) is proposed for monitoring healthcare applications. It is separated into communication and control systems. In the communication system, the carrier frequency used in the human body is 402-405 MHz as medical implant communication systems (MICS) band by FCC and the coexistent wireless communication system (2.4 / 60 GHz) was used to transmit the merged biomedical data in the higher levels of the communication system. An adaptive low power and variable resolution control systems are designed into the control system. In order to improve the performance, a communication cycle is created for synchronizing the WBSN system with pipeline control. Each sensor node consists of a micro control unit (MCU), variable sample rate generator, sensor, ADC, data encoder, 402-405 MHz RF transceiver, and antenna. This paper presents a WBSN system, which not only gains the benefits of more flexible, easy development, run-time reconfigurable and variable resolution, but also significantly reduces considerable power consumptions with adaptive low power design.

A variable control system for wireless body sensor network

There is an increasing need to develop more flexible and intelligent low power wireless body sensor network (WBSN) system for healthcare monitoring applications. Technical advancements in micro-sensors, micro electro- mechanical system (MEMS) devices, low power electronics, and radio frequency (RF) circuits and systems have enabled both design and development of such highly integrated system. In this paper, we present a wireless body sensor network system with the capability of variable resolution function, which enables several resolutions for users selecting. The four levels hierarchical architecture is working well with communication system and control system. The accurate pipeline control will make implement variable resolution design in WBSN system easily and advance the performance efficiently. A variable sample rate generator is designed in each sensor node for producing different sample signals to ADC for variable resolutions. The SNR of ECG can be promoted from 25 dB to 73 dB when extraordinary situation of ECG occurs.

An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs)

In this work, an asynchronous multi-sensor micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE), and an error correct coder (ECC). To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs.

An analog median filter with linear complexity for real-time processing

A new architecture is presented for analog median filters, without the high-accuracy reference voltage, high-speed analog summer, and linear sawtooth wave generator, thereby making it is easy to implement by VLSI technology. The features of this architecture are modular, regular, locally connected and expansible. The throughput is independent of the window size and the hardware complexity is linearly dependent on the window size.<<ETX>>

An Efficient Micro Control Unit with a Reconfigurable Filter Design for Wireless Body Sensor Networks (WBSNs)

In this paper, a low-cost, low-power and high performance micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of an asynchronous interface, a register bank, a reconfigurable filter, a slop-feature forecast, a lossless data encoder, an error correct coding (ECC) encoder, a UART interface, a power management (PWM), and a multi-sensor controller. To improve the system performance and expansion abilities, the asynchronous interface is added for handling signal exchanges between different clock domains. To eliminate the noise of various bio-signals, the reconfigurable filter is created to provide the functions of average, binomial and sharpen filters. The slop-feature forecast and the lossless data encoder is proposed to reduce the data of various biomedical signals for transmission. Furthermore, the ECC encoder is added to improve the reliability for the wireless transmission and the UART interface is employed the proposed design to be compatible with wireless devices. For long-term healthcare monitoring application, a power management technique is developed for reducing the power consumption of the WBSN system. In addition, the proposed design can be operated with four different bio-sensors simultaneously. The proposed design was successfully tested with a FPGA verification board. The VLSI architecture of this work contains 7.67-K gate counts and consumes the power of 5.8 mW or 1.9 mW at 100 MHz or 133 MHz processing rate using a TSMC 0.18 μm or 0.13 μm CMOS process. Compared with previous techniques, this design achieves higher performance, more functions, more flexibility and higher compatibility than other micro controller designs.

Wireless sensor network system by separating control and data path (SCDP) for bio-medical applications

There is an increasing need to develop flexible, reconfigurable, and intelligent low power wireless sensor network (WSN) system for healthcare monitoring applications. Technical advancements in micro-sensors, micro electromechanical system (MEMS) devices, low power electronics, and radio frequency (RF) circuits and systems have enabled both design and development of such highly integrated system. In this paper, we present the wireless sensor network system, which is separated into control and data paths with different transmission frequencies. The control path sends the power and function control commands from computer to each sensor nodes by 2.4 GHz band. There are four levels in the WSN system. The data path transmits measured data from sensor layer to sensor group layer by 2.4 GHz, and transmits between sensor group, application and system layers by 60 GHz. This hierarchical architecture will make it possible to reconfigurable map application to WSN. The accurate pipeline control system will advance the performance efficiently, and the adaptive low power control system will reduce lots of power consumptions.

Low-Power 2.4-GHz Transceiver in Wireless Sensor Network for Bio-medical Applications

There is a low power wireless transceiver system for healthcare monitoring applications in wireless sensor network (WSN). Technical advancements in micro-sensors, micro electromechanical system (MEMS) devices, low-power electronics, and radio frequency (RF) circuits and systems have enabled both design and development of such highly integrated system. In this paper, we present a wireless transceiver for wireless sensor network system, which is considering the link budget for low power design. This hierarchical architecture will make it possible to reconfigurable map application to the WSN system. The accurate pipeline control will advance the performance efficiently, and the adaptive low-power system design will reduce lots of power consumptions. In order to confirm the system, the temperature is regard as the input signals for system performance measurement.

Wireless Thermal Sensor Network with Adaptive Low Power Design

There is an increasing need to develop flexible, reconfigurable, and intelligent low power wireless sensor network (WSN) system for healthcare applications. Technical advancements in micro-sensors, MEMS devices, low power electronics, and radio frequency circuits have enabled the design and development of such highly integrated system. In this paper, we present our proposed wireless thermal sensor network system, which is separated into control and data paths. Both of these paths have their own transmission frequencies. The control path sends the power and function commands from computer to each sensor elements by 2.4 GHz RF circuits and the data path transmits measured data by 2.4 GHz in sensor layer and 60 GHz in higher layers. This hierarchy architecture would make reconflgurable mapping and pipeline applications on WSN possibly, and the average power consumption can be efficiently reduced about 60 % by using the adaptive technique.

Design and implementation of an analogue median filter for real-time processing

A new architecture is proposed for analogue median filters; without the high accuracy reference voltage, high speed analogue summer, and linear sawtooth wave generator; therefore it is easy to implement by VLSI technology. The features of this architecture are modular, regular, locally connected and expansible. The throughput is independent of the window size and the hardware complexity is linearly dependent on the window size.