ASSESSMENT OF WIRELESS COMMUNICATION QUALITY BASED ON INDUSTRIAL NOISE

Transcription

1 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: ASSESSMENT OF WIREESS COMMUNICATION QUAITY BASED ON INDUSTRIA NOISE JUN WANG Depatment of Compute Science & Technology, Shenyang Univesity of Chemical Technology, Shenyang , ioaning, China ABSTRACT Owing to noise in industial envionment, wieless signal is seiously intefeed in industial envionment, and wieless communication quality will be affected seiously. Requiements of industial wieless netwok and the wieless netwok standads ae analyzed in this pape. The wieless communication quality model of IEEE and IEEE802.11b is deduced. The simulation system based on this wieless communication quality model is established by Matlab. The simulation pesents and compaes communication quality of IEEE and IEEE802.11b at the industial noise ange (typically between 20dB and 80 db) and secuity level (IEC61508 defined standad- SI1, SI2 and SI3). Keywods: Communication Quality, Wieless Communication, Industial Noise, IEC INTRODUCTION Wieless communication technology has become a hot spot in the study field of industial netwok contol system based on wieless (WNCS). Wieless technology can bing many benefits to industial netwok contol system. Howeve, wieless technology have not gained widespead acceptance at the factoy floo. One eason is the difficulty in achieving the eal-time and successful tansmission of packets by eo-pone wieless channels [1, 2]. Wieless industial netwoks have ceated inteest in both academia and industy. The fist publications date back to One of the ealiest pojects, the Euopean Union OCHFA poject, stated in June 1992 with the goal to povide wieless spead-spectum tansmission fo the WoldFIP (fomely just FIP) fieldbus. Today, seveal companies and consotia ae active, fo example, the wieless industial netwoking alliance (WINA). They ae consideing the use of standadized wieless technologies like IEEE , BT, o IEEE in a fieldbuscontolled industial netwok. But the communication quality of the existing wieless communication technologies will decline seiously in the wost industial envionments. So the wieless technology is not used widely in the industial field. Fo the pupose of impoving the pefomance of wieless signal tansmission, it is impotant that the wieless communication quality based on industial noise is discussed. So, we summaize equiements of industial wieless netwok, and establish communication quality model, and discuss wieless communication quality based on industial noise by simulation in this pape, which will be useful to enginee and eseaches. 2. REQUIREMENTS OF INDUSTRIA WIREESS NETWORK The equiements of the industial wieless netwok ae included as follows: Reliability: Reliability includes eal-time, deteministic, edundancy etc., it is fa moe impotant than othes. Secuity: The wieless medium is an open medium. Attacke is easy to eavesdop it, and to inset malicious packets, o to jam the medium. These ways will affect system opeation. (c)robustness: it included housing potection level, tempeatue ange, enegy consumption, simple installation and opeation etc. In addition, potocol scalability and enegy efficiency is also equied. 3. WIREESS NETWORK STANDARDS The existing standads of wieless netwok technology (defined by the IEEE) ae divided by netwok coveage. A bief oveview of the vaious standads is as follows [3, 4]: 279

2 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: ) Wieless WAN (IEEE802.20): IEEE is a new mobile wieless standad fo data communications, known as 4G challenge. The coveage of the standad is the same with the existing mobile phone systems. They ae on a global scale. The tansmission ate has eached at the level of Wi-Fi. 2) Wieless MAN (IEEE802.16): IEEE is establishing a wieless access path between the use egion and the backbone netwok. The backbone netwok may be a public telephone netwok o Intenet. 3) Wieless AN (IEEE802.11): IEEE defined that wieless AN can be opeated in the 2.4GHz band, this band is defined the spead spectum band by the global adio egulations entity. On August 1999, IEEE standad had been futhe impoved and evised. A SNMP potocol based on MIB is used to eplace the oiginal OSI potocol based on MIB. It adds two elements. One is IEEE802.11a standad, which exts the physical laye standad. Its woking fequency band is 5GHz, and QFSK modulation is used. The tansmission ate is between 6Mb/s and 54Mb/s. The othe is IEEE802.11b standad. It woks at 2.4GHz fequency band, and uses compensation code keying (CCK) modulation. Its tansmission ate is 11Mb/s. 4) Wieless PAN (IEEE802.15): IEEE commission has developed thee diffeent WPAN standads. IEEE standad is a wieless netwok technology of modeate ate, and it adapts to the shot communication. Its QoS mechanisms ae suitable fo voice sevices. IEEE is a high-ate WPAN standad, and is suitable fo multimedia applications. It has a highe QoS, and it uses UWB technology in physical laye. IEEE standad is a wieless netwok technology of low-powe and low-cost, its taget makets ae industy, families, medical industy and othes. Basic paametes of the above standads [5]-[9] ae shown as Table 1: Table 1: The Basic Paametes Of Wieless Netwok Standad Tansmission 1Potocol Modulation/spead spectum Fequency Range Rate DSSS,FHSS 2.4G 2M 100m a OFDM 5G 6-54M 100m b CCK/DSSS 2.4G 2-11M 100m g OFDM 2.4G 11M,54M 100m FHSS 2.4G 1Mbps 10m Multiband OFDM and DS-CDMA 2.4G 100Mb/s 10m DSSS 868/915MHz 2.4GHz K/s m Single caie and many caies a OFDM 2~11GHz 74Mb/s 50km b OFDM, TDMA and OFDMA 5-6GHz 50km OFDM 3.5GHz below 1Mbps/use 4. WIREESS COMMUNICATION QUAITY MODE Assuming that the signal popagates in fee space, the attenuation coefficient AFS in fee space can be defined as below: A FS ( f ) α (4π ) D f + (1) G G c = 2 T R In the fomula, antenna; C is the speed of light: m/s; G is the gain of omnidiectional T G is the R effective aea of the eceiving antenna. α is coection paamete. is a paamete fo diffeent wieless netwok standad. Now, we suppose that P S ( f ) is the powe spectal density, theefoe, the total tansmits powe P is equal to quadatue of S P S ( f ) in the ange of tansmission fequency. If f and H f ae the uppe and lowe fequency in the ange, the total tansmits powe P is: S fh P = 2 P ( f ) df (2) s f s When the given fomula (1) is used fo attenuation coefficient in fee space, by the method of P.H. Sheng et al [10], signal powe P eceived by eceive can be shown as follow: 280

3 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: P = 2 fh f Ps ( f ) df = 2 A ( f ) FS fh f 1 Ps ( f ) df 2 2 e a(4π ) D f 2 + G G c T R (3) The system magin of the eceive is M. If the S equiements of SNR ae met, the signal powe spec P may be expessed: P = M SNR P (4) s spec N Whee, SNR spec ( i = 1,..., N ) is coesponding to diffeent noise souces. SNR = E / E (6) i i Accoding to channel model and paametes of IEEE and IEEE b in physical laye, we can model and analysis by Matlab. 5. SIMUATION AND RESUT NAYSIS Receive eceives signals by eceiving enegy E in the limited inteval time, E is mainly composed of two components: signal enegy E and noise enegy. Noise enegy may come fom a lot of E noise noise souces. These noise souces ae uncoelated and indepent, such as themal noise, multi-use intefeence and extenal intefeence. So the expession of E is shown as Equation 5. [10]: N = E + i=1 E E = E + E i noise (5) function [f_vecto, PSD_vecto] = theshold_f_psd_vectos(f, PSD, theshold) = length(f); f = f(length(f))/length(f); [P_high,index] = max(psd); f_peak = index * f; P_theshold = P_high*10^(theshold/10); index_max = index; P0h = PSD(index); while (P0h>P_theshold )&(index_max<=) index_max = index_max + 1; P0h = PSD(index_max); f_high = (index_max-1) * f; index_min = index; P0l = PSD(index); while (P0l>P_theshold)&(index_min>1)&(index>1) index_min = index_min - 1; P0l = PSD(index_min); f_low = (min(index,index_min)-1) * f; BW = f_high - f_low; f_vecto = f(index_min:index_max); PSD_vecto = PSD(index_min:index_max); Whee, the paamete f is vecto of fequency ange. The paamete PSD is the powe spectal density of tansmitting wave. This function etuns value f _ vecto, and it is the calculated fequency ange of bandwidth. The paamete PSD_vecto included the initial value of powe spectal density in the scope of bandwidth. The paamete link_m is 5.1 Simulation Fist, we calculate spectal density of Gaussian [10]. Secondly, we must obtain the PSD and fequency (limited ange [ f, f H ] ) by the function (n_gaussian_psd) [11]. Finally, using the above esults and fomula (3), we obtain link budget unde a cetain noise and eo ate. The ealization is as follows: function [R_M_t, R_M_t] = link_budget(link_m,f_noise, f, PSD,Pe, x1, x2) dist=zeos(3,19); Rb=linspace(x1,x2,19); % ate ange M = 2; F = 10^(F_noise/10); % W to dbm convesion l_m = 10^(link_M/10); kt = 1.38e-23; T0 = 300; Gf=1; % Gf said tansmitte antenna gain Gs=1; % Gs that the eceive antenna gain N0 = F*kt*T0; Eb_N0 = logspace(0.5,2); fo i=1:3 Pe_temp = 1; j=1; while Pe_temp > Pe Pe_temp =(1-1/M)*efc(sqt(Eb_N0(j) * 3 * log2(m)/(m^2-1))); Eb_N0_t = Eb_N0(j); j=j+1; fo k=1:19 D_Rb(i,k) = max_distance(gf, Gs, f,psd,l_m, 1/Rb(k), N0, Eb_N0_t); link magin. The paamete F _ noise is noise exponent of the eceive. The paamete x 1 and x2 is ange of tansmission ate. 5.2 Result Analysis Using the above pocedue, we have simulated. Accoding to the defined industy standad [12] (secuity level SI1, SI1 and SI3 in IEC61508, 281

4 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: the data eo ate is fom 10-6 to 10-5 in SI1, the data eo ate is fom 10-7 to 10-6 in SI2, the data eos ate is fom 10-8 to 10-7 in SI3). We can calculate the elationship cuves between the maximum tansmission distance and data ate unde the eo ate P e (10-5, 10-6 and 10-7 ) and the noise exponent (20dB, 40dB, 60 db and 80dB) based on IEEE and IEEE b. The cuves ae shown in Figue 1-4. Figue 2: Relationship of data ate and distance in the noise exponent 40dB Figue 1: Relationship of data ate and distance in the noise exponent 20dB Figue 3: Relationship of data ate and distance in the noise exponent 60dB 282

5 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: noise, Simulation data will be efeence to eseach on industial wieless netwok, and it will be helpful to eseache. REFRENCES: Figue 4: Relationship of data ate and distance in the noise exponent 80dB 6. CONCUSION The wieless channel can influence the design of industial netwok contol system. With the success of wieless technologies in consume electonics, wieless netwok technologies ae envisioned fo the deployment in industial envionments as well. Wieless netwok is, beyond all questions, an appopiate appoach to obtain flexibility and mobility in the factoy. Nevetheless, industial wieless netwok often has stingent equiements on eliability, obustness, secuity and so on. In wied envionments, industial netwok system can satisfy equiements, such as eliability, eal-time, obustness and secuity. Fo example, fieldbus is a matue technology, and it is designed to accomplish communication between digital contolles and sensos. When wieless netwok technologies ae included, due to the advese popeties of the adio channels, the equiements of eliability, obustness and secuity ae significantly moe difficult to be met. So we discuss wieless communication quality based on industial [1] S. Yoo et al., Guaanteeing Real-Time Sevices fo Industial Wieless Senso Netwoks with IEEE , IEEE Tansactions on Industial Electonics, Vol. 57, No. 11, 2010, pp [2] V. Sipal et al., Fequency-selective fading of ultawideband wieless channels in confined envionments, IET Micowaves, Antennas & Popagation, Vol.5, No. 11, 2011, pp [3] Dick Cao, Wieless Netwoks fo Industial Automation, ISA-The Instumentation Systems and Automation Society, Vol.3, No.1, 2005, pp [4] E. Kwon et al., A Pefomance Model fo Admission Contol in IEEE , NCS, Vol.3510, No. 4, 2005, pp [5] R. P. Anand, R. P. Neeli, Pefomance Evaluation System Design and Netwok Deployment of IEEE , Wieless Pesonal Communications, Vol.19, No. 1, 2009, pp [6] K.S. ow et al., Real options and technology management: Assessing technology migation options in wieless industy, Telematics and Infomatics, Vol.26, No. 2, 2009, pp [7] M. Diani et al., Coss-laye modeling of capacity in wieless netwoks: Application to UMTS/HSDPA, IEEE WAN and IEEE WiMAX, Compute Communications, Vol. 30, No. 17, 2007, pp [8] A. Kalis, T. Antonakopoulos, Diection finding in IEEE wieless netwoks, IEEE Tansactions on Instumentation and Measuement, Vol.51, No. 5, 2002, pp [9]. Angisani et al., An IEEE based system fo locating childen on thei school commutes, Tansactions on Fundamentals of Electonics, Vol. E93-A, No.5, 2010,pp [10] J.. Wang, C.G. Wang, UWB communication pinciple and application. Beijng: The People's Posts and Telecommunications Pess, [11] R. Cadinali et al., UWB anging accuacy in high-and low-data-ate applications, Micowave Theoy and Techniques, Vol. 54, No. 4, 2006, pp

6 Jounal of Theoetical and Applied Infomation Technology 30 th Septembe Vol. 43 No JATIT & S. All ights eseved. ISSN: E-ISSN: [12] W.M. Goble, J.V. Bukowski, Exting IEC61508 eliability evaluation techniques to include common cicuit designs used in industial safety systems, Poceedings of the Annual Reliability and Maintainability Symposium, Vol.20, No. 12, 2001, pp