WIRELESS BIOMEDICAL SENSOR NETWORK FOR HOME-BASED

HEALTHCARE MONITORING SYSTEM

MOHD ROZAINI BIN ABD RAHIM

UNIVERSITI TEKNOLOGI MALAYSIA

WIRELESS BIOMEDICAL SENSOR NETWORK FOR HOME-BASED HEALTHCARE

MONITORING SYSTEM

MOHD ROZAINI BIN ABD RAHIM

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Master of Engineering (Electrical)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

FEBRUARY 2011

iii

To my beloved parents, brothers, sisters and friends....

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ACKNOWLEDGEMENT

In the name of ALLAH The Most Gracious and Most Merciful, my utmost

gratitude to Him for giving me strength to complete this thesis. Peace be upon Prophet

Muhammad S.A.W, Family as well as His Beloved Friends.

Here, I would like to express my sincere gratitude to my supervisor Dr.

Sharifah Hafizah Syed Ariffin for her invaluable advice, guidance as well as support

in the effort to accomplish this project. Further appreciation especially to Prof. Dr

Norsheila Fisal and Pn Rozeha Rashid for their guidance, help, advice as well as

criticisms to increase the quality of this project.

I am also very thankful to all my laboratory mates who have helped me both

in my research which included Ariff, Abdul Hadi Fikri, Yaakub Yakubu, Adib,

Nurhija, Kashif, Dr Adel, Hamdan, Kal, Abang Arif, Shidan, Nadia, Izzah and the

practical training students Faiz, Jia, Ika and Ecah. Not forgetting, i would like to

express my appreciation to my family especially Cik Ani bin Mat and Nuurul Afifah

Hussin for continuous support and encouragement which contribute to the successful

of this project.

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ABSTRACT

Wireless Sensor Network (WSN) consists of sensor nodes that interact with

each other to collectively monitor environmental or physical conditions at different

location for the intended user. One of its potential deployment is for the form of

Wireless Biomedical Sensor Network (WBSN) to measure physiological signals. The

WBSN applications would allow the medical practitioners to continuously monitor

and update the status of a patient from a far. This project focuses on the development

of a WBSN platform for home-based healthcare monitoring over WBSN which

complies with IEEE 802.15.4 standard and operates in 2.4 GHz ISM (industrial,

scientific and medical) band. The initial state of WBSN development is the design of

the wireless sensor node called TelG. The main feature of TelG include low power

consumption, wearable, flexible and small size. It is then embedded with a self-built

operating system called WiseOS to support customized operation. The home-based

healthcare monitoring system is able to operate via web-based with the capability

multi-hop real-time communication using Lightweight Real-time Load Distribution

(LRTLD) routing protocol for device discovery. The system is also capable of

displaying patients data which include electrocardiogram (ECG), pulse rate and

temperature. The performance of the TelG is tested experimentally and found to be

comparable with other sensor nodes in the market. The node can achieve packet

reception rate (PRR) above 80% for a distance of up to 6 meters and also for up to 3

hops at different transmission rates. In addition, the LRTLD routing protocol takes

less than 1 millisecond to obtain information on the forwarding node. It is also

observed that the packet transmission rate does not affect the end-to-end delay if the

range of communication is less than 10 m. The WBSN is tested in a real

experimental test bed and are able to successfully provide ECG, pulse rate and

temperature data for remote monitoring of patient at home from the hospital.

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ABSTRAK

Rangkaian Penderia Wayarles (WSN) terdiri daripada nod-nod penderia yang berhubung di antara satu sama lain untuk mengawal persekitaran ataupun keadaan fizikal pada tempat yang berbeza kepada pengguna yang berkenaan. Salah satu penempatan yang berpontensi adalah dalam membentuk rangkaian Penderia Bioperubatan Wayarles (WBSN) untuk mengukur isyarat fisiologi. Aplikasi WBSN membenarkan pengamal perubatan untuk memantau pesakit secara beterusan dan juga dapat mengemaskini keadaan semasa pesakit dari jauh. Projek ini memberi penumpuan kepada pembinaan pelantar WBSN untuk pegawasan kesihatan berpangkalan dari rumah melalui WBSN di mana ia mematuhi piawaian IEEE 802.15.4 dan beoperasi dalam jalur gelombang ISM(industri, sainstifik dan perubatan) 2.4GHz. Peringkat awal pembangunan WBSN ialah reka bentuk nod penderia wayarles yang dinamakan TelG. Ciri-ciri utama TelG adalah termasuk pengunaan kuasa yang rendah, mudah digunakan, fleksibel, dan bersaiz kecil. Ia juga dibenamkan dengan sistem pengendalian binaan diri yang dipanggil WiseOS untuk menyokong penyesuaian operasi. Sistem pengawasan kesihatan berpangkalan rumah mampu beroperasi melalui pangkalan web dengan kebolehan perhubungan lompatan berbilang masa nyata dengan menggunakan protokol laluan Masa Nyata Pengagihan Beban Ringan (LRTLD) untuk pencarian peranti. Sistem juga berkemampuan untuk memaparkan data pesakit termasuk elektrokardiogram (ECG), kadar denyut nadi dan juga suhu. Perestasi TelG telah diuji secara ujikaji dan di dapati setanding dengan nod pengesan yang berada dipasaran. TelG boleh mencapai kadar penerimaan paket (PRR) sehingga 80% untuk jarak sehingga 6 meter bagi jumlah sehingga 3 lompatan pada kadar penghantaran yang berlainan. Tambahan, protokol laluan LRTLD mengambil masa kurang daripada 1 milisaat untuk memperolehi maklumat mengenai nod destinasi. Ia juga menunjukkan bahawa kadar penghantaran paket tidak memberi kesan kepada masa yang diambil dari satu nod ke nod yang lain jika jarak penghantaran adalah kurang daripada 10 meter. WBSN telah pun diuji di dalam ujikaji yang sebenar dan telah berjaya membekalkan ECG, kadar denyutan nadi dan suhu untuk pemantauan pesakit di rumah melalui jarak jauh dari hospital.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF ABBREVIATIONS xvi

LIST OF SYMBOLS xviii

LIST APPENDICES xix

1 INTRODUCTION 1

1.1 Overview. 1

1.2 Problem Statement 3

1.3 Research Objective 4

1.4 Scope of Work 4

1.5 Thesis Outline 5

2 LITERATURE REVIEW 7

2.1 Introduction 7

2.2 Architecture of WSN 7

2.3 WSN Challenges 11

2.3.1 Limited Memory and Storage 11

2.3.2 Energy Constrain 12

2.3.3 Unreliable Transfer 12

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2.3.4 Latency 12

2.4 Routing Protocol in WSN 13

2.5 Wireless Biomedical Sensor Network (WBSN) 15

2.5.1 WBSN Wireless Sensor Node 16

2.5.2 WBSN Routing Protocol 18

2.6 WBSN Application 21

2.7 Summary 26

3 DEVELOPMENT OF A WIRELESS SENSOR NODE 27

3.1 Introduction 27

3.2 Wireless Biomedical Sensor Node Design Requirement 27

3.3 TelG Wireless Sensor Node Design Architecture 29

3.3.1 Processor 29

3.3.2 Transceiver 32

3.3.3 Medical Sensor 34

3.3.4 Power 36

3.4 WiseOS Operating System 37

3.5 Features of TelG Wireless Sensor Node 38

3.5.1 Received Signal Strength Indication (RSSI) 42

3.5.2 Packet Reception Rate (PRR) 44

3.5.3 End-to-End Delay 45

3.5.4 Comparison of TelG with Commercial off-

the-shelf (CTOS)

50

3.6 Summary 52

4 LIGHTWEIGHT REAL TIME LOAD DISTRIBUTION

(LRTLD) MULTI-HOP ROUTING PROTOCOL

DESINGN

54

4.1 Introduction 54

4.2 Routing Protocol Design Requirement 55

4.3 LRTLD Design Concepts 56

4.3.1 Boot Module 58

4.3.2 History Module 58

4.3.3 Receive Queue Module 59

4.3.4 Classifier Module 60

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4.3.5 Neighbour Module 61

4.3.6 Application Module 63

4.3.7 Relay Module 64

4.3.8 Forwarding Module 65

4.3.8.1 Packet Forwarding Destination 66

4.3.8.2 Forwarding Mechanism 67

4.3.9 Transmit Queue Module 68

4.3.10 Assemble Module 70

4.3.11 Network Module 71

4.4 Development of LRTLD Multi-hop Routing Protocol

in TelG

72

4.5 LRTLD Multi-hop Routing Protocol Experiment 72

4.7 Summary 82

5 WIRELESS BIOMEDICAL SENSOR NETWORK

PROTOTYPE SYSTEM

84

5.1 Introduction 84

5.2 Home-Based Healthcare Monitoring System

Architecture

85

5.2.1 Integration of Medical Sensor into TelG

Sensor Node

88

5.2.2 Development of LRTLD Multi-hop Routing

Protocol in TelG

89

5.2.3 Database and Web-Base Development 93

5.3 Experimental Test Bed Prototype 101

5.3.1 Node Deployment 102

5.3.2 Result of Home-based Healthcare Monitoring

System

105

5.4 Summary 109

6 CONCLUSION 111

6.1 Introduction 111

6.2 Future Work 113

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REFERENCES 115

Appendices A - E 123 - 145

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LIST OF TABLE

TABLE NO. TITLE PAGE 2.1 Generic wireless sensor node platform for WBSN

application

17

2.2 Wireless sensor node platform designed specifically for

WBSN application

18

2.3 Existing routing protocol and path selection metrics 19

3.1 Comparison between existing microcontrollers 30

3.2 Current consumption of TelG 41

5.1 The capability of each user to access the web-based 97

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LIST OF FIGURE

FIGURE NO. TITLE PAGE 1.1 WSN application 2

2.1 Typical WSN architecture 8

2.2 Typical wireless sensor node architecture 8

2.3 Layered model for WSNs communication protocol

architecture

9

2.4 Architecture of WBSN 15

2.5 LRTLD design concept 20

2.6 The CodeBlue infrastructure 22

2.7 The MediMesh architecture 23

2.8 MASN design architecture; a) single-hop case; b) multi-hop

case

24

2.9 Scenario and architecture of Medical Implant

Communication Service (MICS)

25

3.1 TelG design architecture 30

3.2 XBee module 32

3.3 System data flow of the XBee module 33

3.4 SPO2 sensor modules 35

3.5 ECG sensor modules 35

3.6 CSN808 sensor board 36

3.7 TelG wireless sensor node platforms 39

3.8 Top view of TelG wireless sensor node 39

3.9 Bottom view of TelG wireless sensor node without battery 40

3.10 Bottom view of TelG wireless sensor node with battery 40

3.11 Packet sending format 41

3.12 RSSI measurement scenarios 42

3.13 RSSI experiment environmental setup 43

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3.14 Effect of distance to RSSI 43

3.15 Effect of distance to PRR 45

3.16 Experiment scenarios 46

3.17 End to end experiment environmental setup 46

3.18 Effect of packet generation and distance to end-to-end delay

for single hop communication

48

3.19 Effect of packet size to end-to-end delay for single hop

communication

49

3.20 End to end delay for multi-hop communication 49

3.21 RSSI versus distance for TelosB and TelG 51

3.22 PRR versus distance for TelosB and TelG 52

4.1 State transition diagram of LRTLD routing protocol 57

4.2 State diagram of Boot Module 59

4.3 State diagram of History Module 59

4.4 State diagram of Receive Queue Module 60

4.5 State diagram of Classifier Module 60

4.6 HELLO packet format 61

4.7 State diagram of Neighbour Module 62

4.8 Application packet format 63

4.9 State diagram of Relay Module 64

4.10 State diagram of Forwarding Module 65

4.11 Flow chart diagram of the forwarding policy in unicast

forwarding for get destination function

69

4.12 State diagram of Transmit Queue Module 70

4.13 State diagram of Assemble Module 71

4.14 Network packet format 71

4.15 Flow chart diagram of development LRTLD multi-hop

routing protocol in TelG wireless sensor node

73

4.16 Grid topology scenarios 74

4.17 Grid topology scenarios in MIMOS Center of Excellence

Training Room

74

4.18 HELLO packet received by (a) node 0, b) node 4, c) node 7,

d) node 10

76

4.19 Node 10 store the neighbour node information into the

neighbour table

77

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4.20 The information of node 6 had been removed from the

neighbour table node 0

78

4.21 Node inserts the new neighbour node information into

neighbour table

79

4.22 Algorithm to calculate the processing time of LRTLD 79

4.23 Selection of forwarding node address by node 10 80

4.24 Condition when the forwarding node is not working or the

battery runs out

81

4.25 Effect of packet generation and hop to the number of packets

received

82

5.1 The system architecture of home-based healthcare

monitoring system

86

5.2 System flow for home-based healthcare monitoring system 87

5.3 Block diagram of TelG-based CSN808 sensor node platform 88

5.4 Top view of TelG-based CSN808 sensor node platform 90

5.5 Front view of TelG-based CSN808 sensor node platform 90

5.6 State diagram of application module in LRTLD based on

TelG-based CSN808 sensor node

91

5.7 TelG-based CSN808 receive data packet format 92

5.8 TelG-based CSN808 transmit data packet format 93

5.9 IEEE 802.15.4 Gateway 94

5.10 State diagram of CSN808 Transfer Data 94

5.11 The CSN808 Transfer Data windows application 95

5.12 Database model diagram at the hospital server 96

5.13 Web-based mapping of home-based healthcare monitoring

system

98

5.14 The login page 99

5.15 Menu displayed after login by doctor 100

5.16 Doctor comment page 100

5.17 Patient data signal display section 101

5.18 Layout of the node deployments at the Telekom Lab room 103

5.19 Node position at the Telekom Lab room 104

5.20 TelG-based CSN808 (node 8) has been attached to the

patient body

104

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5.21 Data received by base station 106

5.22 Data packet received by CSN808 Transfer Data windows

application

106

5.23 The MySQL database at the hospital server 107

5.24 ECG signal from the patient 108

5.25 XCTU screenshot at base station in different time 109

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LIST OF ABBREVIATIONS

ADC - Analog to Digital Converter

AODV - Ad hoc On Demand Distance Vector

API - Application Programming Interface BAN - Body Area Network

CCU - Central Control Unit

COTS - commercial off-the-shelf

CSMA - Channel Sense Multiple Access

ECG/EKG - Electrocardiogram

EEG - Electroencephalography

EEPROM - Electrically Erasable Programmable Read-Only Memory EMG - Electromyography

EMTs - Emergency Medical Technician

GBR - Gradient-Based Routing

GHz - Gigahertz

GPSR - Greedy Perimeter Stateless Routing HHMC - Hospital Health Monitoring Center

HHMD - Hospital Health Monitoring Center

HTML - Hyper Text Markup Language

ISM - The industrial, scientific and medical radio bands

ISP - In System Programming

kbps - kilobit per second

KHz - Kilohertz

LED - Light-Emitting Diode LRTLD - Lightweight Real-Time Load Distribution

LTRT - Least Total-Route Temperature

MAC - Medium Access Control

MASN - Medical Ad hoc Sensor Network

MCE - Mass Casual Event

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MHz - Megahertz

MICS - Medical Implant Communication Service

MTU - Maximum Transmission Unit

NIBP - Non-Invasive Blood Pressure

OF - Optimal Forwarding

OS - Operating System

OSI - Open System Interconnection

PC - Personal Computer

PDA - Personal Digital Assistance

PHP - Hypertext Preprocessor PRR - Packet Reception Rate

QoS - Quality of Service

RAM - Random Access Memory

ROM - Read-Only Memory RSSI - Received Signal Strength Indicator

RTC - Real-Time Clock

RTLD - Real-Time Load Distribution

SMS - Short Message Service

SNR - Signal Noise to Ratio

SPIN - Sensor Protocol for Information via Negotiation

SpO2 - Saturation of Peripheral Oxygen

TCP/IP - Transmission Control Protocol/Internet Protocol

TinyADMR - Tiny Adaptive Demand-Driven Multicast Routing

TQFP - Thin Quad Flat Pack

TRG - Telematic Research Groups

UART - Asynchronous Receiver/Transmitter

WBSN - Wireless Biomedical Sensor Network

WiseOS - Wise Operating System

WSN - Wireless Sensor Network

-

xviii

LIST OF SYMBOL

ta - Arrival time

tt - Transmission time

Pr - Receive power

Gr - Receive antenna gain

Gt - Transmit antenna gain

R - Distance between antenna

Vbatt - Maximum battery voltage

VMbatt - Available battery voltage

Pt - Power transmit

Sr - Receiver sensitivity

PL(d) - Path loss model

Vin - Voltage input

Vref - Voltage reference

d - Distance

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LIST APPENDICES

APPENDIX TITLE PAGE A XBEE Module Specification 123

B CSN808 Specification 127

C RS232 Driver schematic diagram 141

D Base Station RS232 schematic diagram 142

E TelG wireless sensor node schematic diagram 143

F Physiological signal from the patient 145 ��

CHAPTER 1

INTRODUCTION

1.1 Overview

Throughout this decade, Wireless Sensor Network (WSN) has achieved

successful technology, as in WSN applications, node platform manufacturing,

embedded operation system development and network protocol. In the node

platform manufacturing, integrated circuit technologies enable the development of

low-cost, low power and multifunctional sensor node that are small in size. WSN

technology also increases the robustness, fault tolerance, efficiency and flexibility of

the developed embedded operating system and network protocol. WSN composed of

a large number of sensor nodes and multi-hop networking capability that are densely

deployed for a wide variety of applications such as smart buildings, interactive user

interfaces; environment control and highly suitable for monitoring in military and

biomedical applications.

Figure 1.1 shows the various WSN applications. WSN applications can be

classified into two types including tracking application and monitoring application

[1]. Tracking application refers to tracking the location of an animal, human, vehicle

or object. Example of existing WSN tracking application is the Real-time Indoor

Localization for Emergency Responder by Delft University, and ZebraNet [2]. In the

monitoring application, the wireless sensor node has been used to monitor the

activity or behaviour, of as animals, human beings, environment and weather. The

existing application that has been successful implemented are in the Cyclops [3],

WSN in a petroleum facility [4] and paddy field monitoring [5].

2

The implementation of WSN technology in the healthcare application called

Wireless Biomedical Sensor Network (WBSN) application has stimulated great

interest in the development of healthcare monitoring application such as smart home

health monitoring [6], smart ward [7] and athletic performance monitoring [8]. This

WBSN provides the healthcare application more flexibility, reliable, efficient, low

cost, reduced time, secured and power efficient. The WBSN application would allow

the medical practitioners to continuously monitor and update the status of the patient

from a far.

Figure 1.1 WSN application

3

1.2 Problem Statement

The need to effectively design systems which are relatively cheap, scalable,

biologically compatible and energy efficient for health monitoring application is very

crucial. There has been an explosive growth in demand for WBSN in home

healthcare system due to increase in population and technological advancement.

Sensor devices can be used to capture continuous, real-time vital signs from a large

number of patients, relaying the data to handheld computers carried by emergency

medical technicians (EMTs), physicians, and nurses.

Wearable sensor nodes can store patient’s data such as identification, history,

and treatments supplementing the use of back-end storage systems and paper charts.

In a mass casualty event (MCE), sensor networks can greatly improve the ability of

first responders to triage and treat multiple patients equipped with wearable wireless

monitors. This has revolutionalized the medical and health industry by providing

systems which are highly sophisticated and can be used to constantly monitor and

observed patients. Hence, this will reduce the health care cost and allow doctors to

remotely access information about their patient. More importantly, diseases can be

detected in their early stage and diagnose immediately by medical doctors.

It is challenging to meet up with low power, security, delay and throughput

requirements due to time-varying changing wireless environment. Several existing

biomedical devices also do not support the patient mobility since they are wired. For

medical applications, wireless biomedical system should be reliable and secured in

order to ensure effective communication. Medical field has been one of the mission

critical applications which require high precision and accuracy, mobility and good

coverage. This ultimately requires more reliable and robust design to properly

monitor and diagnose patient via WBSN.

4

In order to effectively transport medical data over WBSN, there is a dramatic

need to design energy efficient, economically affordable, flexible, user and

environmental friendly WBSN. This project focuses on the development of the

WBSN to enhance the available service provider in order to support the medical

applications. This project concentrates on the development of the hardware and

software development for wireless biomedical application.

1.3 Research Objective

The goal of this research to develop a WBSN for home-based healthcare

monitoring system. The WBSN will consist of the hardware platform, the operating

system, the routing protocol and the application running on it. Hence, main objective

in the development of WBSN include:

� To design a wireless sensor node platform for WBSN.

� To embed the wireless sensor node with LRTLD multi-hop routing protocol

running in WBSN.

� To develop a home-based healthcare monitoring system prototype on the

proposed WBSN

The proposed design of WBSN will be developed and implemented on a real test bed

environment.

1.4 Scope of Work

The scope of this research is to design a low cost sensor node application for

WBSN. The sensor node design will consists of a processing unit, wireless

transceiver module, data logger, and also medical sensor devices called the TelG

wireless sensor node. The XBEE module will be used as the wireless module.

5

Sensor nodes will be embedded with multi-hop routing protocol called

Lightweight Real-time Load Distribution (LRTLD) multi-hop routing protocol which

provide real-time routing and distributed load balancing. The design and

functionality of LRTLD will embedded in the TelG be studied and developed.

Lastly, A home-based healthcare monitoring system, based on hardware and

software implementation has been developed and integrated with the TelG wireless

sensor node and LRTLD multi-hop routing protocol to relay the data from the patient

body to the base station. The TelG at the patient body will be integrated with

CSN808 medical sensor called TelG-based CSN808 sensor node. The operation on

the system prototype will be investigated in the real test bed implementation.

1.5 Thesis Outline

This thesis consists of six chapters. Chapter 1 serves as an introduction to the

thesis. It covers topics such as problem statement, objectives of the research and

scope of the project.

Chapter 2 provides the relevant background to understand WSNs and WBSN.

The typical WSN architecture will be explained which includes research challenges

and routing protocol in the WSN. The existing wireless sensor node and routing

protocol in the WBSN application will be explained. The related WBSN application

related to the project will also be described.

Chapter 3 describes the design and development of TelG wireless sensor node

platform for WBSN application. The design considerations and the designed

architecture for the development of the wireless sensor node will also be discussed.

6

Chapter 4 explains the Lightweight Real-time Load Distribution (LRTLD)

multi-hop routing protocol. The design concept and requirement of the proposed

multi-hop routing protocol will be explained in this chapter. The proposed multi-hop

routing protocol will be embedded into the TelG wireless sensor node and the

functionality of the purposed multi-hop routing protocol will be investigated.

Chapter 5 presents the biomedical sensor network prototype for home-

healthcare monitoring. The integration between of TelG wireless sensor node

platform and CSN808 medical sensor device will be discussed. The implementation

of TelG wireless sensor node and the LRTLD multi-hop routing protocol in the

home-based healthcare monitoring system will be identified. Lastly the functionality

of the system will be verified by real-time testing and practical implementation.