AN Improved UTD Based Model For The Multiple Building Diffraction Of Plane Waves In Urban Environments By Using Higher Order Diffraction Coeficients

Document Type : Research Article

Authors

1 Corresponding Author, A. Tajvidy is with the Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 A. Ghorbani is with the Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran (e-mail: ghorbani@aut.ac.ir).

3 M. Nasermoghaddasi is with the Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran (e-mail: mn.moghaddasi@srbiau.ac.ir).

Abstract

This paper describes an improved model for multiple building diffraction modeling based on the uniform theory of diffraction (UTD). A well-known problem in conventional uniform theory of diffraction (CUTD) is multiple-edge transition zone diffraction. Here, higher order diffracted fields are used in order to improve the result; hence, we use higher order diffraction coefficients to improve a hybrid physical optics (PO)-CUTD model, the results show that the new model corrects errors of the PO-CUTD model. Therefore, the proposed model can find application in the development of theoretical models to predict more realistic path loss in urban environments when multiple-building diffraction is considered.

Keywords


[1]     H. L. Bertoni,” Radio Propagation for Modern Wireless Systems” Prentice-Hall, Englewood Cliffs, NJ, 2000.
[2]     COST 231, European Commission, “Digital mobile radio toward future generation systems” Brussels, Belgium, 1999.
[3]     W. Zhang, “Fast two-dimensional diffraction modeling for site-specific propagation prediction in urban microcellular environments,” IEEE Transaction o Antennas and Propagation, Vol. 49, No. 2, 428–436, Mar. 2000.
[4]     J. Wolfish, and H. L. Bertoni, “A theoretical model of UHF propagation in urban environments,” IEEE Transaction on Antennas and Propagation, Vol. 36, No.12, 1788–1796, Dec. 1988.
[5]     S. R. Saunders, and F. R. Bonar, “Explicit multiple building diffraction attenuation function for mobile radio wave propagation,” Electron. Letter, Vol. 27, No. 14, 1276–1277, Jul. 1991.
[6]     S. R. Saunders, and F. R. Bonar, “Prediction of mobile radio wave propagation over buildings of irregular heights and spacings,” IEEE Transaction on Antennas and Propagation, Vol. 42, No. 2, 137–144, Feb. 1994.
[7]     M. J. Neve, and G. B. Rowe, “Contributions toward the development of a UTD-based model for cellular radio propagation prediction,” Proc. IEE Microwave. Antennas Propagation, Vol. 141, No. 5, 407–414, Oct. 1994.
[8]     W. Zhang, “A more rigorous UTD-based expression for multiple diffractions by buildings,” Proc. IEE—Microwave. Antennas Propagation, vol. 142, no. 6, pp. 481–484, Dec. 1995.
[9]     W. Zhang, “A wide-band propagation model based on UTD for cellular mobile radio communications“, IEEE Transactions on Antennas and Propagation, vol. 45, no. 11, pp. 1669–1678, Nov. 1997.
[10]  L. Juan-Llácer and N. Cardona, “UTD solution for the multiple building diffraction attenuation unction for mobile radio wave propagation," Electron. Letters, vol. 33, no. 1, pp. 92–93, Jan. 1997.
[11]  A. Kara and E. Yazgan, “UTD-based propagation model for the path loss characteristics of cellular mobile communications system,” in Proc. IEEE Int.Symp. Antennas and Propagation Society, vol. 1, Orlando, FL, pp. 392–395, 1999.
[12]  C. Tzaras and S. R. Saunders, “An improved heuristic UTD solution for multiple-edge transition zone diffraction,” IEEE Transactions on Antennas and Propagation., vol. 49, pp. 1678–1682, Dec. 2001.
[13]  L. Juan-Llácer and J. L. Rodríguez, “A UTD-PO solution for diffraction of plane waves by an array of perfectly conducting wedges,” IEEE Transactions on Antennas and Propagation, vol. 50, no. 9, pp. 1–5, Sep.2002.
[14]  R. Arablouei and A. Ghorbani, “A new UTD-based model for multiple diffractions by buildings,” in Proc. 3rd Int. Conf. Microwave and Milimeter Wave Technology, St. Petersburg, Russia, pp.484–488, Jun. 2002.
[15]  D. Erricolo, G. D’Elia, and P. L. E. Uslenghi, “Measurements on scaled models of urban environments and comparisons with ray-tracing propagation simulation,” IEEE Transactions on Antennas and Propagation, vol. 50, no. 5, pp.727–729, May 2002.
[16]  D. Erricolo, “Experimental validation of second-order diffraction coefficients for computation of path-loss past buildings,” IEEE Transaction  Electromagnet. Compact, vol. 44, no. 1, pp. 272–273, Feb. 2002.
[17]  J.-V. Rodríguez, J.-M. Molina-García-Pardo and L. Juan.Llácer, “An improved solution expressed in terms of UTD coefficients for the multiple-building diffraction of plane waves,” IEEE Antennas and Wireless Propagation Letters, vol. 4, 2005.
[18]  E. Torabi, , A. Ghorbani and H.R. Amindavar, “Modification of the UTD Model for Cellular Mobile Communication in an Urban Environment,” Electromagnetics, Vol. 27, 263-285,Jun. 2007.
[19]  A. Tajvidy, and A. Ghorbani, “A New Uniform Theory-of-Diffraction-Based Model for the Multiple Building Diffraction of Spherical Waves in Microcell Environments,” Electromagnetics, Vol. 28, 375-388, Jun. 2008.
[20]  E. Torabi, A. Ghorbani and A. Tajvidy, "A Modified Diffraction Coefficient for Imperfect Conducting Wedges and Buildings with Finite Dimensions" IEEE Transactions on Antennas And Propagation. Vol. 57, No. 4, 1197-1207, Apr. 2009.
[21]  R. G. Kouyoumjian and P. H. Pathak, "A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface". Proc. IEEE. Vol. 62, 1448–1461, 1974.
[22]  M. F. Catedra and Jesus Perez-Arriaga, Cell Planning For Wireless Communication, Artech House, Inc., 1999, ch. 9.
[23]  P. D. Holm, "Calculation of Higher Order Diffracted Fields for Multiple-Edge Transition Zone Diffraction", IEEE Transactions on Antennas and Propagation, Vol. 52, No. 5, pp. 1350-1355, MAY. 2004.
[24]  P. D. Holm, “A new heuristic UTD diffraction coefficient for no perfectly conducting wedge,” IEEE Transactions Antennas and Propagation, Vol. 48, No.8, 1211-1219, Aug. 2000.