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fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Panitz, Mark
Languages: English
Types: Unknown
Subjects:
This thesis develops efficient tools for modelling wireless communications within highly resonant environments. The aim of these tools is to augment analysis of wireless systems inside closed metallic cavity environments. The primary application for these systems is within the aerospace industry where weight and space are restricted and robustness is critical. The use of ever-advancing wireless communication options would offer significant weight and cost savings and increase safety through supplementing or the replacement of wired systems. The use of a low power wireless system offers the greatest advantage in terms of flexibility and weight. Accordingly, the most suitable applications of the wireless systems are discussed in terms of existing avionic systems. The electromagnetic properties of the aircraft environment and parameters to characterise both the properties of the environment and the wireless signal are introduced. Efficient models are then developed, which characterise the resonant and associated multipath nature of the cavity based on an equivalent circuit approach. The efficiency of these models permits the use of a statistical modelling approach, akin to reverberation chamber measurement techniques, in order to generalise the results for typically non-constant modal structures. Finally, a fractional boundary placement model is developed to augment the transmission line modelling method and permit boundary placement at non-integer positions within a structured mesh. The technique provides a semi-conformal capability with no deleterious impact on the modelling time step. This is then extended to a dynamic model for modelling structural variations during the simulation. A subset of wireless communication approaches is presented and the effectiveness and suitability of such systems are discussed. The developed models are applied to characteristic environments and a selection of the wireless communication methodologies in order to provide examples of their use and an insight into the effect of these environments upon a wireless system.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • 1 Introduction 1.1 Advantages of Wireless . 1.2 Practical Considerations 1.3 Possible Applications . 1.3.1 Flight Control 1.3.2 Engine Control 1.3.3 Utilities . . . . 1.3.4 Health Monitoring 1.4 Scope of this Thesis and Contributions . 1.5 Thesis Stucture . . . . . . . . . . . . . .
    • 2 Parameter Definitions 2.1 Representative Environments of Interest 2.1.1 Single Resonant Environment . . 2.1.2 Coupled Resonant Environment . 2.1.3 Dynamically Varying Structures 2.2 Definition of Parameters 2.2.1 Quality Factor 2.2.2 Mean Excess Delay . 2.2.3 Q Factor and Mean Excess Delay Relationship 2.2.4 Density of Modes . 2.3 Bit/Packet Error ratio . . Communication Systems of Interest 3.1 System Requirements 3.2 Modulation Techniques 3.2.1 Amplitude Shift Keying (ASK) 3.2.2 Frequency Shift Keying (FSK) 1 2 8 10 11 11 12 12 13 16 19 20 20 22 22 22 23 26 27 31 34 37 38 40 40 41 3.2.3 Phase Shift Keying (PSK) . . . . . . . . . 3.2.4 Quadrature Phase Shift Keying (QPSK) . 3.2.5 Minimum Shift Keying (MSK) 3.2.6 Modulation Bandwidths 3.3 Spread Spectrum Techniques 3.3.1 DSSS . 3.3.2 CDMA 3.3.3 FHSS .
    • 3.4 Complete Communication Systems 3.4.1 ZigBee . . 3.4.2 Bluetooth 3.4.3 Wireless LAN . 3.4.4 Summary. 3.4.5 References .
    • Modelling of a Single Resonant Cavity 4.1 Modelling Approach . . .
    • 4.2 Equivalent Circuit Model 4.3 Obtaining Circuit Parameters 4.3.1 Analytical . . 4.3.2 Data Fitting 4.4 A Statistical Approach to Channel Modelling Modelling of Multiple Coupled Cavities 5.1 Problem Description . . . .
    • 5.2 Aperture Coupled Cavities. 5.2.1 Two Slot-Coupled Cavities 5.2.2 Multiple Slot-Coupled Cavities 5.2.3 Effect of Slot Orientation . . . 5.2.4 Analytical Coupling Coefficients 5.2.5 An Efficient Cavity Model . 5.2.6 Validation.......
    • 5.3 Waveguide Coupled Cavities. 5.3.1 Waveguide Containing a Wire. 42 43 46 49 51 53 56 59 59 60 61 62 62 63 65 67 69 76 77 81 89 94 95 96 96 105 107 110 114 120 122 126
    • 6 Dynamic Models of Cavities 6.1 Requirements . . . . 6.2 Existing Approaches 6.2.1 Graded Mesh 6.2.2 Stub Model . 6.3 New Boundary Development 6.3.1 2D model 6.3.2 3D model 6.3.3 Validation . 6.4 Non-PEC Boundaries 6.4.1 Magnetic Boundary 6.4.2 Lossy Boundary 6.5 Internal Boundaries 6.5.1 Validation . . 6.6 Time Varying Boundaries 6.6.1 Model Development 6.6.2 Validation . . . . 6.6.3 Model Stability .
    • 7 Propagation and Wireless Modelling Examples 7.1 Model Summary . . . . . . 7.2 Resonant Cavity Problems. 7.2.1 BPSK . . . . . 7.2.2 Filtered BPSK 7.2.3 Bit Period. 7.2.4 Summary 7.3 Fractional Boundary Problems 7.3.1 Practical Impact of Vibrations 7.4 Acute Angle Modelling . . . . . . . . .
    • 8 Conclusions 8.1 Possible Wireless System Modelling. 8.2 Concluding Remarks . . . . . . . . .
    • A Sequences for Spread Spectrum Techniques A.I Maximal-Length Sequences A.2 Gold codes . . . . . . . . .
    • B Cavity Resonance from Geometric Optics B.I A Geometric Optics Approach B.2 Example Problem . . . . . . . .
    • C TLM Stub Calculations C.I Stub Calculation in 2D . C.2 Stub Calculation in 3D .
    • [32] ZigBee Alliance, "ZigBee specification," June 2005.
    • [33) W. H. Press, S. A. Teukolsky, W. T. Vetterling, and B. P. Flanllery, Numerical Recipes in C++. Cambridge University Press, 2nd cd., 2002.
    • [34] R. C. Dixon, Spread Spectrum Systems. Ncw York: John Wilcy & Sons, 2nd ed., 1984.
    • [35) P. T. 'I'rakadas ct. a1., "Computation oftransmission-linc immunity level in til<' presense of a direct-sequence spread-spectrum electromagnctic signal by using CE-FDTD method," IEEE Transactions on Electromagnetic Compatibility, vol. 45, no. 1, pp. 2-9, 2003.
    • [36] R. L. Pickholtz et. aI., "Theory of spread-spectrum communications - a tutorial," IEEE Transactions on Communications, vol. COM-30, no. 5, pp. ~55 884,1982.
    • [41] J. M. De Freitas, Digital Filter Design Solutions. Artcch House, 2005.
    • [42J C. Christopoulos, Principles and Techniques of Electromagnetic Compatibility. CRC Press, 1995.
    • [43] A. V. Oppenheim and R. W. Schafer, Digital Signal Processing. Prcnticc-Hall, NJ, 1975.
    • [44J R. S. Barbosa, J. A. T. Machado, and M. F. Silva, "Time domain design of fractional differintegrators using least-squares," Signal Processing, vol. 8(i, pp. 2567-2581, 2006.
    • [45J D. Hope, J. Dawson, A. Marvin, M. Panitz, C. Christopoulos, and P. Scwcll, "Assessing the performance of zigbee in a reverberant ellvirOlllJlCllt using l\ modc stirred chamber," IEEE International Symposium on Electromagnetic Compatibility, Detroit, Aug. 2008.
    • [46J H. A. Bethe, "Theory of diffraction by small holt',s," 7'he Physical RctJir.tJI, vol. 66, pp. 163-182, October 1944.
    • [47] H. A. Wheeler, "Coupling holes between rcsonant cavitics 01' wl\V(~g\lidt~ eVl\luated in terms of volume ratios," IEEE 1hmsaction..4 on MicrotllatJe 11&cory and Techniques, pp. 231-244, March 1964.
    • [48J N. A. McDonald, "Electric and magnetic coupling through SUll\1l l\J>emt.lln~ in shield walls of any thickness," IEEE Transactions on Microtllatlc The.orll and Techniques, vol. 20, pp. 689-695, October 1972.
    • [49] C. H. Liang and D. K. Cheng, "Electromagnetic fields coupled into a cavity with a slot-aperture under resonant conditions," IEEE Tran,~action.~ on Antennas and Propagation, vol. AP-30, pp. 664-672, July 1982.
    • [50] N. Marcovitz, Waveguide Handbook. New York: New York Dovcr Publications, Inc., 1st ed., 1951.
    • [51] H. Du, P. So, and W. J. R. Hoefer, "Cells with tensor properties for conformal TLM boundary modeling," 2006 IEEE MTT-S Int. Microwave Syrup. Dig., pp. 157-160, 2006.
    • [52] U. Mueller, A. Beyer, and W. J. R. Hoefer, "The implementation of filllOothly moving boundaries in 2D and 3D TLM simulations," IEEE MTT-S, pp. 791- 792, June 1992.
    • [53] U. Mueller and A. Beyer, "Moving boundaries in 2D and 3D TLM simulations realized by recursive formulas," IEEE Transactions on Microwave Theory and Techniques, vol. 40, pp. 2267-2271, December 1992.
    • [54] J. Paul, C. Christopoulos, D. W. P. Thomas, and X. Liu, "Tinw-domnill modeling of electromagnetic wave interaction with thin-wires using TLM," IEEE Transactions on Electromagnetic Compatability, vol. 47, no. .9, PI>. 447 455, Aug. 2005.
    • [55] J. Paul, C. Christopoulos, and D. W. P. Thomas, "Corrcction to "time-domain modeling of electromagnetic wave interaction with thin-wircH using TLM" ," IEEE Transactions on Electromagnetic Compatability, vol. 50, no. 2, pp. ·150 451, May 2008.
    • [56] L. Gaffour, "Analytical method for solving t.he onc-dimnllsionai wnve equation with moving boundary," Progress In Electromagnetics RrsraTy:h, vol. 20, pp. 63-73, 1998.
    • [57] I. S. Grant and W. R. Phillips, The Elements of Physics. Oxford, UI<: Oxford University Press, 2001.
    • [58] L. W. Couch II, Digital and Analog Communication 8ystcfll.~. Pn'utkt' Hall, 7th cd., 2007.
    • [59] D. Davidson, Computational Electromagnetics for RF and Mi(,TYJllIatlf! Engineering. Cambridge University Press, 2005.
    • [60) R. G. Manley, "Vibrations in aircraft: A series of articles covering tilt' g('/)­ eral principles for aeronautical engin<..'Crs," Aircraft. Enginecritlg and A(,TYJ'~lm('(' Technology, vol. 16, no. 2, pp. 38-49, 1993.
    • APPENDIX C. TLM STUB CALCULATIONS Combining the respective terms we obtain (6.3.39) and (6.3.38).
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