Bluetooth wireless communications on the application of medical care

Current medical care cannot be dynamically acquire patient information, once the patients symptoms get worse, not the first time implemented where data information maintenance low efficiency.

The article first describes the Bluetooth technology and its application in the medical monitoring of feasibility, and then designed the system framework that gives specific features BlueTooth Wireless Communication Technology Application in Medical Monitoring including data acquisition and voice alarm, and finally on the Bluetooth signal-jamming during transmission characteristics are analysed.

Introduction

Current medical monitoring devices mostly by independent equipment components, through print or screen display.

Access to patient information needs a lot of work, nurses need to keep to the patient bedside observation important data on the monitor and record potential input error. How to direct from medical equipment to collect patient information automatically and through the network to the database, real-time, remote monitoring of patients, the current urgent medical care. Bluetooth technology with FH fast, short, low power data packets, stability, strong anti-interference ability, the small radiation for solving the above problems. The article features based on Bluetooth technology, wireless monitoring and control system design, and a key part of the programme.

1 Bluetooth technology and features

1.1 Bluetooth technology

SIG organizations on 26 July 1999 launched the Bluetooth specification version 1.0.

Bluetooth system structure is divided into three parts: the underlying hardware modules, intermediate protocol layer and senior application. The underlying hardware section includes wireless frequency hopping [1] (RF), baseband (BB) and link management (LM). Wireless frequency hopping PassThru 2.4GHz without authorization of ISM band of microwave, realization of data bit stream filtering and transfer, this layer protocol mainly defines the Bluetooth transceiver in the band working conditions required to meet. Baseband is responsible for frequency hopping and Bluetooth data transmission and information frame. Link management is responsible for the connection, set up and dismantle the link and security controls.

Bluetooth technology is a combination of circuit-switched and packet switching characteristics, can be asynchronous data communication, can support up to three simultaneous synchronous voice channel, you can also use a channel transmit asynchronous data and synchronize voice.

Intermediate layers including logical link control and adaptation protocol, Service Discovery Protocol, serial port emulation protocol and telephone communication protocol.

Logical link control and adaptation protocol has the complete data access, control of quality of service, and multiplexing Protocol functionality, this layer protocol is the other layer protocol implementations. Service discovery protocol layer for upper-layer applications provide a mechanism to discover network services and features available.

Host controller interface (HCI) is the Bluetooth protocol interface between software and hardware, it provides a call to baseband, link management, status and control register, the unified command interface hardware.

Bluetooth devices to communicate, HCI above Protocol software entity running on the host, the following features by HCI Bluetooth devices to complete, in between both ends by a transparent transport layer. In the Bluetooth protocol stack from the top is a variety of high-level application framework.

The Bluetooth system typically consists of four functional modules, as shown in Figure 1.

Figure 1 the Bluetooth system functional unit

1.2 Bluetooth feature

(1) work in 2.56GHz ISM band

(2) use frequency hopping spread spectrum [2] FHSS technology

(3) a slight NET supports eight devices

(4) to transfer the equipment shall not be directed

(5) in the range of 10 m to 100 m

(6) costs low, each piece of Bluetooth chips for about $ 20

(7) power to 1mW

(8) the use of external power amplifier can be effectively extends 100 meters

2 Bluetooth technology in the medical monitoring of

2.1 system hardware structure design

Figure 2 medical monitoring system framework diagram

Medical monitoring system hardware structure consists of a central processing chip MSP430F449, Bluetooth chip, and other peripheral module (voice modules, data extraction module, keyboard and LCD, etc.).

Medical monitoring system of the overall structure of the framework shown in Figure 2.

2.2 hardware introduction

(1) MSP430F449 chip

Microchips are MSP430F449 chip, by United States TI company produces an ultra-low power as the main characteristics of a single-chip 16 with highly integrated, wide ambient temperature range, high-precision A/D conversion and other technical performance, with serial communication interface, a hardware multiplier, LTD drive circuit and high anti-interference ability, etc.

(2) the Bluetooth chip

BRF6100 is ti (TEXAS INSTRUMENTS; TI).

The Bluetooth baseband, RF, memory, power management, PLL, Loop filter, antenna switch and integrated into a single chip filters, also take the lead in copper 0.13 micron CMOS process. According to TI, to enhance the effectiveness of the chip, lower costs, reduce machine Board area is three major characteristics. BRF6100 Applies to 802 .11b collaboration I/F and TI OMAP mobile wireless LAN, [3] platform, TCS chipset solution seamlessly integrates with its advanced architecture in the use of a digital RFProcessing of unique high-performance handling characteristics but also follows the TI 0.13u digital CMOS process technologies.

BRF6100 's features include:

· Process: 0.13u CMOS

· Use electricity: 25mA

· Voltage: 1.7-3.6V

· Sensitivity:-85dBm (0.1% BER)

· Integrated RF Switch

· Maximum transmission speed of 723.2K/s

· At-40 to + 85 ° c temperatures

· A maximum of seven Slave device for transmission

2.3 system principle

The Bluetooth monitoring equipment in each ward, with medical equipment connected to collect patient information.

Through the base station receiver, the patient's information and the address of its own base station information, via RS485 bus sent to adjacent to a base station receiver, then from the base station until the upload is sent to a central server, from a central server for data analysis, processing, and to provide features such as query, management. Various departments can always understand patient information to the remote monitoring of patients, once the patient's condition worsened, Bluetooth monitoring equipment will alarm signal is transmitted to a central server, care staff can immediately determine the patient's room number and the patient to take emergency measures. Monitoring equipment distribution as shown in Figure 3.

Figure 3 monitoring equipment distribution map

Data acquisition and alert the flowchart shown in Figure 4.

Figure 4 system flowchart

3 Bluetooth interference characteristics analysis

Bluetooth technology for low cost, low power consumption, with unique immunity.

(1)-robust performance analysis

In the Gaussian noise environments, system without interference conditions: in the bit error rate (BER) 0.1% of incoming C/IAWGN 21dB reached.

In order to ensure that the receiver is not subject to interference, signal power receivers must be greater than the receiver sensitivity RXSENX, according to the following formula to calculate the carrier to interference ratio [4] are:

Of these, GN total noise gain, G-amplifier, N0 + 10logB (dBm) for the receiver input additive white Gaussian noise power, N0 (dBm/Hz) receive noise density, B (Hz) for the receiver receives the signal bandwidth.

(2) resistance to co-channel interference performance analysis

Bluetooth device in the guarantee system availability has taken some measures, such as the use of frequency hopping, error-correcting codes [5], ARQ mechanism, HEC algorithms, etc.

4 closing

Based on Bluetooth wireless technology for medical monitoring system utilizing Bluetooth network capacity, low power consumption, real-time, and other advantages, the use of Bluetooth chips to achieve BRM6100 Bluetooth wireless positioning and communication base stations, wireless base station sends a signal to a central server, you can implement control center for ambulatory care.

Bluetooth wireless technology with transmission distance short transmission signal may be interfered, and so on, to a certain extent, affected the Bluetooth technology in medical applications. With Bluetooth technology continues to mature, the Bluetooth technology in medical applications will become more and more widely.

This innovation point: take full advantage of the features of Bluetooth technology, the Bluetooth technology and existing medical equipment, medicine, dynamic extraction of patient information, remote monitoring of patients, to more sophisticated medical care system.

Reference documents

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[2] Li. A Bluetooth wireless sensor network implementation [J]. a micro-computer information, 2006 (20): 244-246.

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[4] Yang Guang Sung, stone jianghong, Sun Jian-min. Bluetooth anti-interference technology and 2.4GHz wireless network frequency coexistence analysis [J]. Information technology, 2003 (9): 9-10.

[5] the horse barn, Roy runner-up, Zhao Ting. Bluetooth core technologies and applications [M] £ ® press, 2003: 184-185.