with the threshold value, alarm monitoring are done,real-timeresults are stored to RAM,the data are sent to mobile phonesvia GPRS, to monitor the human body in real-time.Fig 2. Family health monitoring systemThis system is mainly used to monitor some the physio-logical data of the human body,such as temperature, pulse,blood pressure, So there should be two data transmission, thatis indoor transmission and outdoor transmission .The systemselected Zigbee as the indoor transmission and GPRS as theoutdoor transmission.IV. THE WIRELESS COMMUNICATION TECHNOLOGY INHEALTHCARE SYSTEMCompared to traditional wired communications, wire-less communications has advantages of timeliness, mobility,flexibility and low cost. In addition, the range of wirelesscommunications can be not limited in environmental condi-tions,which can transmit several tens of kilometers outdoorand from tens of meters to several hundred meters indoor, italso has an equivalent security and encryption measure withthe wired network in data transmission of the network.Thewireless communications include Short-range wireless com-munication technology and long-distance wireless communi-cation technology.A. The short-range wireless communication technologyThe short-range wireless communication is mainly usedfor indoor transmission, nowadays Zigbee, Wi-Fi, Bluetoothand Ultra Wide Band are more popular. The short-range wire-less communication which has been implemented in thehealthcare system including Bluetooth and Zigbee .Bluetooth is a short-range wireless communicationtechnology specification which proposed by Ericsson in 1994,this specification uses the wireless connection instead ofwidely used connection. Bluetooth is an open wirelesscommunications standard , which based on the IEEE802.11standard technologies of wireless LANs.It promotes andexpands the range of application of wireless communication,which makes a variety of data in the network and voiceequipment can be interconnection, as a result, fast and flexibledata transmission and voice communications is achievedwithin the personal area.Table 1. the performance comparison of four short-range wireless com-munications technologycommuni-cationstechnologyZigbee Bluetooth Wi-Fi UWBtransmissionfrequency2.4G/915M/868MHZ2.4GHZ 2.4/5GHZ3.1-10.6GHZcoverage 10-100m 10m 100m 10mtransmissionrate250/40/20kbps1Mbps 11/54Mbps480-1000Mbpsbattery lifesix months-two yearssome days some hourssomemouthstransmitpower0.5-3mw 1-10mw 50-70mw <1mwnetworknodes65000 7 32 unknownfrequencyapplicationsno no noavailableonly toU.S.the size ofstack15-40k 60-150k 100-250kstandardization isnotcompleteimmunity strong less strong less strong strongsecurityAES-128 64/128bitAuthentication SSIDAEScost low high high highSensor nodeZigbeesensornodetempera-ModulephoneARMmoduleGPRSmodulepulseBloodpressureZigbee technology is a kind of short-range wirelesscommunications technology which has uniform technicalstandard , the standard regards the low power, lowcommunication rate transmission, low-cost as an importantgoal, whose PHY layer and MAC layer protocol is based onIEEE802.15.4 protocol standard. It is a technology programbetween wireless mark technology and Bluetooth,which hasbroad application prospects in the industrial control, consumerelectronic equipment, car automation, intelligent of homes andbuildings, wireless sensor networks, medical monitor andother fields.Wi-Fi is not mean that the wireless network but aorganization of wireless networks which is formulated by802.11. Its biggest advantage is the high transmission speed,while besides,its effective range is not only very long,but alsocompatible with the existing variety of 802.11DSSS devices.UWB is a non-carrier communication technology, whichtransmit data with non-sinusoidal narrow pulse of nanosecondto picosecond-level. It is siad that a revolutionary progress inthe field of radio,which would become the future mainstreamof short-range wireless communications technology. UWBtechnology was originally developed as a military radartechnology, which is mainly used for the radar technologyearly. February 2002, the U.S. FCC approved UWBtechnology for civilian use, and then the pace of developmentof UWB gradually accelerate.A number of performance parameters and theircomparative advantages and disadvantages of the indoortransmission above 4 short-range wireless communicationtechnology are listed in Table 1 and Table 2.
Table 2. the comparative advantages and disadvantages of four short-range wireless communications technologycommunications technology advantage disadvantageZigbeez low power consumptionz cost-effectivez small equipmentz strong anti-interferencez big network capacityz a wide coveragez low transmission ratez need to stack on the host sidez require a corresponding networkBluetoothz equipment is widely installedz the optimized ad-hoc networkz small network capacityz high power consumptionz compared to Zigbee,more expensivez short transmission distanceWi-Fiz good mobilityz building a network quickly and easilyz faster transmission rate than Bluetoothz relatively wide coveragez relatively large power consumptionz costs are higherz worse security than BluetoothUWBz small transmission powerz high transmission ratez wide bandwidthz strong anti-interferencez big communication capacityz small coveragez high costz available only to U.S.z standardization is not completeLow-rate, low power, low cost are required in the familymonitoring system.According to these factors, the Zigbee isused in the family monitoring system to meet all therequirements. First, two pieces of battery can last six monthsto two years,maybe even more in Zigbee network. Second, thecost of Zigbee is nearly 1/10 of other wireless communicationtechnologies in the way of oversimplifying protocols. Third,the Zigbee,which can cover 10-100m,meets the requirement ofindoor transmission.Fourth, 250 Kbps transfer rate of the Zig-bee just to be fine for human physiological datatransmission,and it still has the network capacity, strong anti-interference, high security and so on.Therefore, the Zigbee isused in the indoor transmission of family monitoring systemachieve good effect and is suitable for China of less wealth.B. Long-range wireless communication technologyLong-range wireless communication is mainly used foroutdoor transmission, such as GSM, GPRS, CDMA, CDPD.GSM, GPRS and CDMA has been successfully used in familymonitoring system.GSM (Global System for Mobile Communications) isthe worlds most popular standard for mobile telephony sys-tems. It is considered as a second generation (2G) mobilephone system.GSM system is the more sophisticated and themost widely used of a long-distance wireless communicationsystem in mobile communication system that based on TDMAtechnology.GPRS is General Packet Radio Service for short,which isa data transmission technology that is based on GSM.It is2.5G mobile data network ,which has all the advantages ofGSM and has been upgraded.GPRS is different form the wayof continuous transmission in the channels (such as GSM),Ittransmits the data in the form of packet,in which the channel isshared and only when it is necessary there is data packet.CDMA is Code-Division Multiple Access for short, it isnot only a channel access method used by various radio com-munication technologies,but also a second generation digitalmobile communication system based on CDMA. It is based onIS-95 standards, and is developed by the Qualcomm company,they are both 2G technology with GSM network. This stan-dard has been used by more than 100 operators and more than60 countries including Hong Kong, Korea, Canada and theUnited States.CDPD is Cellular Digital Packet Data for short,It is awireless data communication technology specification ofCDPD system,which launched jointly by the U.S. mobilecommunications company (AMCI) and other eight companies,this specification is based on digital packet data technology.As can be seen from Table 3, GPRS technology is usedfor the outdoor data transmission of family monitoring system,transmission quality is very stable, and the transmission dis-tance can always reach up to the local GSM network, so as toachieve real-time monitoring purposes. the frequency and thequantity of physiological data is not large, so the GPRS-communication fee is very low.
Table 3.the comparative advantages and disadvantages of four Long-range wireless communications technologycommunications technology advantage disadvantageGSMz wide coveragez relatively stablez communication protocol complexz after-sale service work hardz data communication service function is limitedGPRSz high-speed transmissionz forever onlinez affordablez rapid loginz wide coveragez relatively stablez high-speed transmission through sacrifice channel sourcesz encryption verification mechanism is not very goodCDMAz large capacityz good communication qualityz high confidentialityz strong anti-interference abilityz small radiationz users lessz multi-access interferencez strong signal has obviously drafting role to the weak signalCDPDz high-speed transmissionz high safety of dataz wide bandwidthz the restrictions of channel number and the ratez users lessz high delayV. CONCLUSIONThis paper analyzes wireless communications technologyof the family health monitoring system, including short-rangewireless communication technology and long-range wirelesscommunication technology,The advantages and disadvantagesof commonly used techniques were contrasted respectively,this paper selects Zigbee as the indoor transmission and GPRSas the outdoor transmission. This system combines Zigbee andGPRS in family health monitoring system, which can not onlymeet the main requirements, but also achieve real-time moni-toring purposes.ACKNOWLEDGMENTThis work is supported by the Fundamental Research Funds ofXi’an Polytechnic University (No. 2010JC02), and the Re-search Funds of Shaanxi Provincial Education Office(No.2010JK564).REFERENCES Joonyoung Jung1 , Kiryong Ha1, Jeonwoo Lee1 Youngsung Kim2 andDaeyoung Kim3. Wireless Body Area Network in a UbiquitousHealthcare System for Physiological Signal Monitoring and HealthConsulting. International Journal of Signal Processing[J].ImageProcessing and Pattern Recognition.2008,pp47-54(2008) Pei Zhi-jie, Ding Xiao-di. Development of Wireless Remote MedicalMonitoring System [J]. Computer & Digital Engineering, 2008 1255-58 Li Wen-zhong, Duan Chao-yu,et al. The Introduction and ActualCombat of Zigbee Wireless Network Technology[M].Bei Jing:Aerospace University Press, 2007.4 Guo Shi-fu, Ma Shu-yuan, Wu Ping-dong, Chen Zhi-long. Pulse WaveMeasurement SystemBased on ZigBee Wireless Sensor Network[J].Application Research of Computers, 2007.4 258-260 Wang Cai-feng, Liu Zhi-gui, Meng Gang. Design of Medical MonitoringSystem based Bluetooth Technique and GSM Communication[J].Control and Automation Publication Group, 2008 24 6-1 134-135 77 Guo Jin-song, Hao Jun, Deng Qin-kai. Application Research of GPRS inPhysiological Data Remote Transmission[J]. Microcontrollers &Embedded System, 2004.7 15-17