Proceedings of the 2011 IEEEIICME International Conference on Complex Medical Engineering

May 22 - 25, Harbin, China

Design of Embedded Remote Monitoring Terminal Based on 3G Network

Zhongbao Peng1,2,3 Chao HU2,3

1. School of Electronic and Information Engineering South China University of Technology

Guangzhou, China

Jingsheng Liao2,3 Tianhai Chang1

2. Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences

Shenzhen, China 3. The Chinese University of Hong Kong

Hong Kong, China

pzbquan@163.com chao.hu@siat.ac.cn

Abstract-In the paper we describe the terminal of remote monitoring system based on embedded and 3G network. It implements the acquisition of physiological parameters such as

the ECG, blood pressure, respiration, blood oxygen, and sends the read-time data to remote doctor workstation for display and storage through the 3G network. This paper discusses Linux system migration of the monitoring terminal, design of device driver, 3G wireless module and standardized software interface.

Keywords-3G Network, remote monitor, Embedded, Wireless

I. INTRODUCTION

With the rapid development of science and technology, the quality of people's lives and health level enhances unceasingly. Meanwhile, the aging of the popUlation is becoming a global phenomenon. As the demographic survey shows, China is entering the aging society. Along with the quickening process of aging population, lots of elderly people suffered from all sorts of chronic diseases, and health problems of elderly people also became the focus of attention. Chronic diseases are persistent or recurring conditions that require care for a long time and that limit the patient's activities. So the monitoring system between individual and hospital are very helpful for these patients [1-3]. In addition, based on the demand of improving the doctor's work efficiency in the hospital, it also makes remote monitoring system more and more attractive. Therefore, the design of a remote monitoring system is very necessary.

At present, the terminal of remote monitoring system that based on either PC or wired can't satisfy clinical needs, which are usually cumbersome and expensive, inconvenience in use. The coming of 3G era make a portable telemonitoring system with high data transfer rate possible [4-6], at the same time, the advance of embedded microprocessor technology enable us to design low cost and compatible system with sufficient data processing capability.

The paper presents the design of the 3G embedded remote monitoring system, which implements the acquisition of physiological parameters such as the ECG, blood pressure, oxygen, and sends the read-time data to remote doctor workstation for display and storage through the 3G network.

978-1-4244-9324-1/11/$26.00 ©20 11 IEEE 274

js.liao@siat.ac.cn thchang@scut.edu.cn

�en the exception of patients physiological is happened, it wIll report the situation to the doctor, so that patients can be get treatment in time, but also save medical expense.

II. THE OVERVIEW OF THE SYSTEM

The diagram of the embedded remote monitoring system based on 3G network is shown in figure 1. It mainly includes two parts: family monitoring terminal and doctors workstations [7].

Working principle: the family monitoring terminal is mainly composed of multiple physiological parameters monitor circuit, the embedded system that based on S3C2440

�d 3G communication module. Family monitoring terminal Implements the acquisition of physiological parameters such as the ECG, blood pressure, blood oxygen, respiration, temperature. The embedded system are used to process and store these physiological parameters, display them in LCD, transmit these data through 3G wireless modules. The doctor workstation will store and display data coming from remote monitoring terminal, and can remotely administer these terminals by sending control commands through network, so that can monitor the patient real-timely.

III. THE DESIGN OF THE SYSTEM

A. The overview of monitoring terminal hardware Considering factors of system such as stability and cost,

monitoring terminal adopts Samsung's microprocessor S3C2440 as control core. The system hardware is composed of five parts. There are: physiology information acquisition module, the ARM processor, periphery connection circuit, 3G communication module and touch screen interface.

S3C2440 is a section microprocessor of Samsung based on ARM920T core of 16/32 RISC [8], which contains a low p�,,:er, sampling maintain, 8 channel, 10-bit ADCCAnalog-to DIgItal Converter). Sampling rare can reach 500K SPS in 2.5 MHz conversion clock. Periphery circuit consists of 64M SDRAM and 128M Nand Flash data storage that using large capacity high-speed FLASH ROM to store various

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nCG Module

Blood Oxygen Module

Blood Pressure Module

Respiration Module

L-____ --l: I I I I

Remote Monitoring Terminal : I

------------r = [j =: = = = =: = = = = = = = = = = = = = = = = =--L _____ .P!!t!!b.!'� _________ �c.!��o.!:�s.!a.!i2'! _____ :

Figure 1. Schematic diagram of the system.

Application

Software Interface

................. _._._._-_._-----_._._-_ ................. _._._._._._._._._._._ .... -............... _-------... _---_._._._ ................. _._._._.

Figure 2. Software hierarchical structure.

physiological data in real time for few days. Besides large Flash capacity provide a guarantee for data security, the outside enlarge SO card can guarantee of the data gathering for a long time.

B. The overview of software design Software component mainly includes Linux embedded

operating systems, drivers and network transmission applications. Software hierarchical structure is as shown in figure 2:

Linux operating system is a very popular embedded system at present, which is characterized by completely free, open-source, flexible cutting, network supporting. So we choose Linux as the software platform of family monitoring terminal. The drivers such as ADC driver [9-11], serial ports scan etc, realize the underlying function and provide support for upper software interfaces. 30 module achieves the function of Wireless network connections for system. Software interface layer provides a unified operation interface, which will improve the maintainability of the program and scalability.

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Application Layer

Software Interface

Laver

Driver Layer

Device Layer

IV. THE DESIGN OF SYSTEM SOFTWARE

A. The design of software interface Integrating modules such as Blood pressure, blood oxygen,

ECO, breathing module into the system, we must provide a unified software interface to improve the scalability of system. Each device module corresponds to the device t structure, device t structure diagram is as follows:

device t I paramJeeder_t

I ctl t

Figure 3. device_t structure.

Dev info t is used to describe general information of equipme�t. (parser_t is used in system calls to realize equipment specific data analysis; l_signal_ feeder _t is the signal data interface which is supplied by device for system calls; I-'param_feeder_t is the data parameters interface which is supplied by device for system calls; I_ctU is the

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readO lyarseu->parserO

[§J , , , ,

, , , , , t=> Parser data

l_signal_feeder_t->write_signaIO :-

1_ ctrl->send _ cmdO

, , :

Lead switch

Figure 4. ECG data transmission and standard leads switching process.

control interface of instruction which is received by device from system calls. To realize UJarser_t, I_signaljeeder_t, I�aramjeeder_t, I ctI t interface, according to the equipment characteristics and set NULL if you don't use.

Take ECG module for example, ECG module should be realized: 1) I�arser_t interface for system call to parse equipment data; 2) I_signal_feeder_t interface, and assign system callback to write_signal, device module can transfer signal data to the system through the callback function; 3) 1_ ctI_t, used to receive switching commands of standard leads. Typical process is shown in figure 4.

B. Lima system customization As the use of embedded Linux is very flexible, users can

cut and customize it on the basis of need. The main steps are as follows:

1) Establish crossover development environment in Linux. 2) Set target board of makefile files for the ARCH: = arm

in kernel source. And the set cross-compiling tools address. 3) Use the command of make menconfig into kernel

configuration. Compile the kernel, establish kernel image files.

C. ADC driver For the external devices, it is essential to write device

drivers for working in Linux environment. Take ADC driver for example, this ADC driver support 2 channels sampling simultaneously, which support periodic sampling of timer driven. Each channel can set ADC frequency of and buffer size alone. The design thought of ADC driver are as follows: first is to initialize equipment, including sampling channels, prescaler frequency, sampling rate, registering ADC interrupt and the size of the KFIFO [12]. When the timer interrupts, ADC begin to collect data and the data is preserved in kernel buffer.

AID converter driver is typical character driver, offering flow control interface for application. The operating method of the file_operation struct is initialized as follows: Static struct file_operations dev _fops = {

owner: THIS_MODULE, open: s3c2440_adc_open, read:S3c2440 adc read ioctI: s3c2410 adc ioctI release:S3c2440_adcJelease,

276

} S3c2440_adc_open function is to finish settings and

initialization of related timer registers when opened at the first time, ADC initialization and registered interrupts for timer and ADC. Timer interrupt handling procedures is used to implement for launching AD sampling, sampling data in character is stored in kernel buffer. S3c2440 adc read is used for the AID data in kernel buffer to transfer to user space in short integer. S3c241O_adc_ioctI is used to implement various control command, including changing sampling channel number, sampling rate, etc. As contrary as S3c2440_adc_open, S3c2440_adcJelease is mainly used for resource release and device closed. The driver obtains major device number using dynamic allocation mechanism, so could not create device node previously. In order to load the device driver using dynamic major device number, call a simple script replace the command of insmod. Read Iproc/devices after call insmod in the script in order to obtain major device number which is new assigned, and create device file accordingly, application get ECG data by accessing to ECG device.

D. 3G communication module (1) The introduction of the PPP

PPP(Point-to-Point Protocol) is utilized to establish a connection between 3G module and the gateway in this project. PPP is a kind of link layer Protocol based on TCP/IP Protocol. The layer provides full-duplex operation and transmits packets in sequence. The PPP is one of the most widely used protocols in WAN, which has the advantage of sample, user authentication, IP address allocation. (2) PPP dialup tools in Linux

3G card itself does not support PPP, so require a series of tools for PPP dialup (such as chat, pppd, etc) to realize PPP protocol and Linux kernel support. With the network script of 3G dialup, the terminal can be networked to the doctor workstation. (3) USB mode switch

There are multiform methods of connection between 3G module and host, such as RS232 interface, USB to serial port and so on. 3G module establishes physical electrical connection s with client terminal by use of USB to serial port.

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Figure 5.The prototype of remote monitoring termial. Figure 6. The waveform of I lead ECG.

Figure 7. The waveform of 0 lead ECG. Figure 8.The waveform of 1II1ead ECG.

Figure 9. Doctor workstation result

But at present, to make 3G card work in the USB to serial mode under linux environment, there are two methods. One is to modify USB driver in linux kernel, and then recompile the kernel. In this way, if you change other card, you have to repair and recompile the kernel driver. The other is to use tools in user space and convert storage mode to serial port mode, which needs the support of related DLL. Considering all elements, we adopt the second method in this project. In linux platform common conversion tools such as usb - modeswitch, need the support of dynamic repository of libusb. Usb - modeswitch and dynamic repository of libusb need to undertake cross­compiling in linux so that generate executable grogram that is suited to target board .

Critical code: pppd connect 'chat -v "" "AT" "" "ATDT#777

CONNECT''' user CARD password CARD Idev/ttyUSBO 230400 nodetach crtscts debug usepeerdns defaultroute

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First pppd program calls chat conversation program, whose purpose is to dialup and wait for the trip. Then according to user name and password that you entered, start pppd in the server, verify identity, and end chat conversation program. Pppd program continues the work instead of chat, establishes the PPP connection with pppd in server.

V. TEST AND RESULTS

The whole system has been basically designed and tested. Figure 5 shows the monitoring terminal based on 3G Network, including ECG module ,blood pressure module, blood oxygen module and so on.

Wireless data transmission of the whole system is in real time tested from remote monitoring terminal to the doctor workstation with no mistakes. Figure 6, 7, 8 respectively display I lead ECG, II lead ECG and III lead ECG waveforms through the transmission of 3G wireless Network.

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In the remote workstation, the doctor monitoring software using C # received data from family monitor terminal, and stored data in a database, which is also responsible maintenance and management for medical record database. It includes waveforms of ECG, blood pressure, respiration, blood oxygen and measured parameter value. The results of blood oxygen signal at the doctor monitoring workstation is shown as Figure 9.

VI. CONCLUSION AND FUTURE WORK

This paper introduces the design of remote monitoring terminal, which is a combination of modem embedded technology, communication technology and medical sensor technology. The system implements the acquisition of physiological parameters such as the ECG, blood pressure, blood oxygen, etc, for long periods, and realizes real-time wireless monitoring, which has overcome traditional monitor feature, such as simple, single parameter, huge volume and so on. At present we has completed the prototype of remote monitoring terminal that based on 3G and embedded Linux, which has small, powerful, easy to use, low cost and other characteristics, making the remote monitoring system have a wide range of applications and good market prospects.

In the future, we will do more jobs to complete our system: 1) Improve the stability of network connection further and

provide secure high capacity data storage. 2) Design the mechanism of handing errors for system,

which will make the operations more user-friendly and intelligent.

3) The provision of log function, operation procedures and records error message.

ACKNOWLEDGMENT

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This work is supported by the grants from National Sc. &

Tech. Pillar Program(2008BAI65B21), the Guangdong/CAS Cooperation Project(2009B091300160), Shenzhen Sc. & Tech. Research Funds, and the Knowledge Innovation Eng. Funds of CAS. The authors would like to thank for Yuanqi Liu, Yang Yang, Mingkai Chen, and Bin Xu's valuable comments that improved the quality of the paper significantly.

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