||A Wireless Real-Time Multichannel Physiological Signal Monitoring System for Multiple Freely Moving Rats
||Institute of Computer Science and Information Engineering
Wireless body area network (WBAN)
freely moving rat
Continuous multichannel electroencephalography (EEG) monitoring is crucial for clinical diagnosis in epilepsy. In clinical practice, video/EEG monitoring is the golden standard for seizure detection, but analyzing long-term video images are time-consuming for experts and the video images are difficult to interpret automatically by computers. Accelerometer/EEG monitoring can be an alternative solution for video/EEG monitoring. Although applying wireless body area network (WBAN) to continuous monitoring not only reduces medical costs in hospitals but also improves the quality of patients’ lives, moving body or multiple moving nodes contributes to most of packet losses in WBAN. Hence, reliably coordinating wireless links between multiple moving nodes and guaranteeing integrity of received data are challenging issues for WBAN.
In this thesis, we propose a wireless real-time multichannel physiological signal monitoring system designed for measuring EEG and motion signals from multiple freely moving epileptic rats. The proposed system is capable of long-term continuous monitoring. Physiological signals are transmitted wirelessly via IEEE 802.15.4 communication technology and shown in a graphic user interface (GUI) in real-time. The proposed system implemented a time division multiple access (TDMA) protocol for the purpose of power saving and high bandwidth utilization. Moreover, a low-overhead time synchronization method was proposed, which can dynamically adjust the transmitter clock without extra synchronization messages and oscillator frequency measurement in advance. The proposed system was proved to work successfully on multiple freely moving rats and achieved more than 99% received data integrity during 24 hours recording.
CHAPTER 1. INTRODUCTION 1
1.1 Background and Motivation 1
1.2 Thesis Organization 5
CHAPTER 2. RELATED WORK 6
2.1 Health Monitoring Devices 6
2.2 Time Synchronization 7
2.2.1 Reference Broadcast Synchronization 8
2.2.2 Timing-sync Protocol for Sensor Networks 8
2.2.3 Flooding Time Synchronization Protocol 9
CHAPTER 3. DESIGN AND IMPLEMENTATION 10
3.1 Overview 10
3.2 Hardware Architecture 11
3.2.1 Microcontroller Module 11
3.2.2 Sensor Module 12
3.3 Software Architecture 13
3.3.1 MAC Protocol 13
3.3.2 Packet Format 14
3.3.3 Packet Retransmission 15
3.3.4 Time Synchronization 19
3.3.5 User Interface 23
CHAPTER 4. EXPERIMENT AND EVALUATION 26
4.1 Retransmission Policy 26
4.2 Real-World Experiment 26
4.2.1 Experimental Setup 26
4.2.2 Overall Experimental Results 27
4.2.3 Statistic of Packets 28
4.2.4 Effect of Moving Subjects on PRR 30
4.2.5 Throughput 31
4.3 Existing MAC Protocol Comparison 32
4.4 Time Synchronization 33
4.5 Power Consumption 36
4.6 Signal Demonstration 37
CHAPTER 5. DISCUSSION 40
CHAPTER 6. CONCLUSION AND FUTURE WORK 42
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