Wireless communication inside mines and tunnels is very different from that in terrestrial environment because of the strong attenuation of signals. Here, we are developing an empirical model for the underground wireless communication channel based on experimental data which help in predicting the average received signal strength at a given distance from transmitter. The model aims at adding correction factors to the available outdoor and indoor propagation models such as Okumara-hata model, cost231 model, ITU indoor propagation models etc. Modeling is done by choosing the most appropriate model among the available ones and performing regression methods to the model based on experimental data. Correction factors are then added based on two parameters which we are considering namely- Penetration and Scattering loss for 0.3GMSK

JAYARAM, M. N.

VENUGOPAL, C.R.

English

Interscience Research Network

International Journal of Electronics Signals and Systems Volume 3 Issue 4 Article 15 April 2014 UNDERGROUND WIRELESS COMMUNICATION CHANNEL MODELING AND SIMULATION USING 0.3GMSK MODULATION CONSIDERING PENETRATION AND SCATTERING LOSS M. N. JAYARAM Department of E&C, SJCE, Mysore570006, Karnataka, India, jayaram_mn2002@yahoo.com C.R. VENUGOPAL Department of E&C, SJCE, Mysore570006, Karnataka, India, venu713@gmail.com Follow this and additional works at: https://www.interscience.in/ijess  Part of the Electrical and Electronics Commons Recommended Citation JAYARAM, M. N. and VENUGOPAL, C.R. (2014) "UNDERGROUND WIRELESS COMMUNICATION CHANNEL MODELING AND SIMULATION USING 0.3GMSK MODULATION CONSIDERING PENETRATION AND SCATTERING LOSS," International Journal of Electronics Signals and Systems: Vol. 3 : Iss. 4 , Article 15. DOI: 10.47893/IJESS.2014.1188 Available at: https://www.interscience.in/ijess/vol3/iss4/15 This Article is brought to you for free and open access by the Interscience Journals at Interscience Research Network. It has been accepted for inclusion in International Journal of Electronics Signals and Systems by an authorized editor of Interscience Research Network. For more information, please contact sritampatnaik@gmail.com. UNDERGROUND WIRELESS COMMUNICATION CHANNEL  MODELING AND SIMULATION USING 0.3GMSK MODULATION CONSIDERING PENETRATION AND SCATTERING LOSS   M.N.JAYARAM1 & C.R.VENUGOPAL2  1,2Department of E&C, SJCE, Mysore570006, Karnataka, India  E-mail : jayaram_mn2002@yahoo.com , venu713@gmail.com   Abstract- Wireless communication inside mines and tunnels is very different from that in terrestrial environment because of the strong attenuation of signals. Here, we are developing an empirical model for the underground wireless communication channel based on experimental data which help in predicting the average received signal strength at a given distance from transmitter.  The model aims at adding correction factors to the available outdoor and indoor propagation models such as Okumara-hata model, cost231 model, ITU indoor propagation models etc. Modeling is done by choosing the most appropriate model among the available ones and performing regression methods to the model based on experimental data. Correction factors are then added based on two parameters which we are considering namely- Penetration and Scattering loss for 0.3GMSK.   I. INTRODUCTION   Underground mines which are characterized by their tough working conditions and hazardous environments require fool-proof mine-wide communication systems for smooth functioning of mine workings and ensuring better safety. Proper and reliable communication systems not only save the machine breakdown time but also help in immediate passing of messages from the vicinity of underground working area to the surface for day-to-day normal mining operations as well as for speedy rescue operations in case of disaster. Therefore, a reliable and effective communication system is an essential requisite for safe working, and maintaining requisite production and productivity of underground mines. Most of the existing systems generally available in underground mines are based on line (wired) communication principle, hence these are unable to withstand in the disaster conditions and difficult to deploy in inaccessible places.   Therefore, wireless communication is an indispensable, reliable, and convenient system and essential in case of day-to-day normal duty or disaster situations.   The wireless communication systems used on surface cannot be applied straightaway in underground mines due to high attenuation of radio waves in underground strata, besides presence of inflammable gases and hazardous environment. Non symmetric mine topology, uneven mine structure and complex geological structures put further hindrance on the way of communication. Wireless communication in underground mine is a very complex technique.  We have used simple modulations like BFSK,BPSK &0.3GMSK . II.  AVILABLE PRACTCAL DATA,  CALCULATION AND RESULTS  1.  Terrain Profile Underground mines consist of slopes, rocks, edges etc. This peculiar type of confined environment is characterized by very rough surfaces and a frequent absence of a line-of-sight between transmitting and receiving antennas. The resulting propagation characteristics differ from those frequently encountered in more typical indoor environments such as offices and corridors. This type of terrain profile limits the signal strength which makes it difficult for wireless communication. An approximate model of the underground channel taking such a terrain into consideration is done. Wireless communication in an environment which consists of soil or rock is more challenging than through air.  The approximate terrain profile inside mine is shown in figure 1.1    Figure 1.1: Approximate terrain elevation inside mine Power measurements are done at distances of 1m (point A), 14m (point D) and 30m (point C).These points are selected because  these are critical points.         International Journal of Electronics Signals and Systems (IJESS), ISSN:2231-5969, Vol-3, Iss-4293 Underground Wireless Communication Channel Modeling & Simulation Using 0.3gmsk Modulation Considering Penetration & Scattering Loss 2.  Available Practical Data Measurements carried out in a gold mine  using a high performance transceiver . probable losses that occurs at points A,D&C are listed in table 1.1 . Table 1.1: The prominent losses at points A,D & C in the mine Points Losses considered during propagation A Penetration    loss+   machinery   loss+   power    line interference loss   D Penetration   loss+   multi   path   loss+   power   line interference loss.   C Penetration   loss+   multi   path   loss+   power   line interference loss+ bending loss.    The measured values of the total loss( transmitted signal strength – measured signal strength in dB ) at A,D and C point considering three modulation formats BPSK, BFSK and 0.3-GMSK are given in Table 1.2:  Table 1.2: The measured values of losses at points A, D & C Points BPSK BFSK 0.3GMSK A 119.7185 119.7185 119.7185 D 137.4461 134.7918 132.5873 C 150.2984 147.9036 146.1967  3.  Modeling. Three basic models which are used in terrestrial communication are considered.  3.1   Selection of model We consider 3 propagation models and then use one of them as the base for modeling.   Table 1.3: Losses obtained from cost 231 model at A,D & C    Where L= Total path loss in dB, f= Frequency of transmission in MHz, d= Distance in meter, N= Distance power loss coefficient, n= Number of floors between the transmitter and receiver, Pf(n)=Floor loss penetration factor. In GSM 900MHzband , floor attenuation factor Pf(n)=24, no of floors N=33 and considering distance d in m, the losses at points A,D and C are given in Table:1.4  Table 1.4: Losses obtained from ITU model at A,D  & C Points Loss(dB) A(d=1m) 55.462 D(d=14m) 93.285 C(d=30m) 104.2076  Log distance path loss model Mathematical equation is given by   L= 20 log (4*π*d/ λ) + 10* γ *log(d/d 0 ) + X g ------------(1.3) Where λ=Wavelength, d=Distance in meter, X g =Fading factor, γ=Path loss exponent, d 0 =Reference distance. For Wave length in GSM 900MHz band , reference distance d 0 =1m, fading factor X g =0,path loss exponent γ =2, the losses at points A,D and C are given in Table:1.5  Table 1.5: Losses obtained from Log distance path loss model at A,D & C Points Loss(dB) A(d=1m) 55.462 D(d=14m) 93.285 C(d=30m) 104.2076  The best model for further calculations is found by comparing the measured values of loss with the losses obtained from model equations.         International Journal of Electronics Signals and Systems (IJESS), ISSN:2231-5969, Vol-3, Iss-4294 Underground Wireless Communication Channel Modeling & Simulation Using 0.3gmsk Modulation Considering Penetration & Scattering Loss  Figure 1.2 Measured & model path loss plot  3.2 Deviation of measured loss from model losses. The deviation between the two losses are given in Table1.6  Table 1.6: The mean error from the differences of losses calculated from the models and measured losses Models Mean error Cost231 model 20.202 ITU model 49.82 Log distance path loss model 67.253  Since Cost231 model has the lowest mean error. Hence, it is considered for all further calculations.  3.3 Calculation of correction factor to the selected model. In the first step, correction factors w.r.t distance are added to the model using differences between model calculated and measured values.  Table 1.7: Differences between losses obtained from cost231 model and measured losses for 0.3GMSK modulation. Points Loss(dB) A(d=1m) 5.159 D(d=14m) 30.993 C(d=30m) 28.57 First a plot of the differences vs. log d is drawn as in Fig 1.3 below.    Fig 1. 3 loss vs logd curve Polynomial regression is then performed by using the basic fitting tool in mat lab to obtain correction factor.   Thus, we obtain a correction factor   C1=5.2+41(log 10 d)-18(log 10 d)  (1.4)    Incorporating in eq(1.1) ,  we have     L=46.3+33.9logf-13.82log(h B  )-a(h R  )+(44.9-6.55logh B  )    – C1 ---------------------------------------------  (1.5)  Figure 1.4 shows the corrected cost231 model w.r.t distance    Figure 1.4: Plot of corrected cost231 model vs. distance  III. ANALYSIS OF PARAMETERS  Further corrections in the model are obtained by considering two parameters: penetration & scattering losses. Multi path loss is assumed to be 40 dB , using Fresnel’s model bending loss 34.63 dB & power line loss is 57.9 dB (measured using magnetic dipole).  1.  Penetration loss. There was a 35 cm thick concrete brick wall at the entrance which results in penetration loss. For lossy dielectric medium  γ² =(α+jβ)² =(σ+jωЄ)( jωμ)………...(1.6) So Attenuation constant α ≈ σ/2√(μ/Є) Dielectric constants at 900MHz GSM band are listed in table1.8.For concrete this loss is 16 dB .  Table 1.8: Value of constants.  Now at point C the losses considered are: Penetration loss+ multipath loss+ bending loss+ power line interference loss, We take penetration loss to be variable , let it be given by some term k3 ,hence the total loss becomes: L=K3 +40+34.63+57.9 The correction factors are derived using the basic fitting tools in MATLAB. Thus, we obtain a second correction factor C2=10.58log10f-173         International Journal of Electronics Signals and Systems (IJESS), ISSN:2231-5969, Vol-3, Iss-4295 Underground Wireless Communication Channel Modeling & Simulation Using 0.3gmsk Modulation Considering Penetration & Scattering Loss Adding it to the already corrected cost231 model we get the final cost231 model as, L=46.3+33.9logf-13.82 log(hB)- a(hR)+(44.9-6.55loghB) logd - C1-C2------(1.7)  Scattering loss: At point C total loss is L=Penetration loss+ multipath loss+ power line interference loss. Considering multipath loss ( MPC) as variable   we have L= 16+40+57.9+MPC Using polynomial regression method we use MATLAB for curve fitting and find the third correction factor as   C3=-0.01*d^2+0.45*d-40 Adding it to already corrected Cost 231 model we get the model after scattering correction as: L=46.3+33.9logf-13.82 log(hB)- a(hR)+(44.9-6.55loghB) logd - C1-C2-C3. The final plot of corrected model is as in Fig 1.4   Figure   1.4:   Shows the Plot of final corrected cost231 model.  IV. CONCLUSION   1. Point C ( at a depth of 30m ) is selected because it is the critical point in the terrain . 2. 0.3 GMSK modulation is used . 3. High power of   is used to overcome penetration loss at entrance . 4.  Beyond 30m as more than 75% of the received signal was attenuated measurements was not possible. 5.  We have used super position while modeling i.e for penetration loss we have assumed scattering loss as constant 7 vice versa . 6.  Model can be updated by considering antenna height loss (due different planes of TX &RX ) , bending loss, low frequency interference loss as variables . 7.  Parameters like loss due to fan, blowers, lighting , ground reflection can be considered . 8. This model may not work in other mines due to change in geometry.  REFERENCES  [1]. Theodore.S. Rappaport, Wireless communications, Principle and practice, Eastern Economy Edition, 2nd ed, 2002. [2]. William C.Y.Lee, Mobile communications engineering, Theory and applications  [3]. Gilles, Y. Delisle. School of information technology & engg, University of Ottawa,  Canada Underground mine wireless propagation modeling  [4]. Signal propagation techniques in underground mines. http://www.ece.gatech.edu/research/labs/bwn/surveys/underground09.pdf [5]. Helchel. IEEE transaction on antenna & propagation, ‘Comparison of 900 MHz band and  800 MHz band indoor propagation ‘vol 54, No 12, Dec 2006 [6]. Shi Lihua, Xu Qiwei, Chan Bin Gao Cheng Measurement of the frequency dependent   Dielectric constant of concrete materials by TDR & wavelet modeling method Asia pacific  Conference on environmental electromagnetic. CEEM 2003, Nov 4 – 7. [7]. Hindawi Publishing Corporation , International Journal of Antennas and Propagation  , Volume 2008, Article ID 806326, 10 pages,doi:10.1155/2008/806326 [8]. Raj Jain, “Channel models a tutorial, Feb 1,2007” [9]. About Modulation Format. http://en.wikipedia.org/ wiki/Modulation [10]. C. Nerguizian, C. L. Despins, S. Aff`es, and M. Djadel, “Radiochannel,characterization of an underground mine at 2.4GHz,”,IEEE Transactions on Wireless Communications, vol. 4, no. 5,pp. 2441–2453, 2005. [11]. Zhi, S. and I. F. Akyildiz, \Channel modeling of wireless net-works in tunnels," IEEE Global Telecommunications Conference,(GLOBECOM'08), New Orleans, LA, Nov. 30{Dec. 4, 2008). [12]. Empirical formula for propagation loss in land mobile radio service, IEEE transactions on  Vehicular Technology, VOL. VT-29, NO.3, AUGUST 1980 [13]. About Radio Propagation Models. http://en.wikipedia.org/wiki/Radio_ propagation model [14]. About Path Loss. http://en.wikipedia.org/wiki/Path_loss [15]. Bertoni, H. L., Radio Propagation for Modern Wireless Systems Prentice Hall, Englewood Cli®s, NJ, 2000. [16]. M. Boutin, A.Benzakour, C.Despins and S. Affes. (2008). Radio wave characterization and modeling in underground mine tunnels, IEEE. Transaction. on Antennas and Propagation, 2:540-549. [17]. 17. M.Lienard and P.Degauque. (2000). Natural Wave Propagation in Mine Environments, IEEE Transaction on Antennas  and propagation, 48(9):          1326-1339. [18]. 18. W.E.Pakala and V.L.Chartier     Radio noise measurements on overhead power lines from  2.4to 800kv,    [19]. M.Ndoh and G.Y.Delisle. (2004). Underground mines wireless propagation   modeling, 60th IEEE Vehicular Technology Conference, Los Angeles,  CA, 3584-3588. [20]. Kjeldsen, E. and M. Hopkins, \An experimental look at RF prop-agation in narrow tunnels," Proc. IEEE Military CommunicationsConf. (MILCOM'06), Washington D.C., Oct. 23{25, 2006 [21]. Li Wenfeng, Lv Yingli, Li Baiping. (2008). Experiment on characteristic of radio propagation in mine. Journal of Xi an University of Science and Technology, 2:327-330 (in Chinese.         International Journal of Electronics Signals and Systems (IJESS), ISSN:2231-5969, Vol-3, Iss-4296

UNDERGROUND WIRELESS COMMUNICATION CHANNEL MODELING AND SIMULATION USING 0.3GMSK MODULATION CONSIDERING PENETRATION AND SCATTERING LOSS

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UNDERGROUND WIRELESS COMMUNICATION CHANNEL MODELING AND SIMULATION USING 0.3GMSK MODULATION CONSIDERING PENETRATION AND SCATTERING LOSS

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