volume | PIER Journals

Abstract

The advantages of integrating beamforming Butler matrix in 4×4 Multiple-Input Multiple-Output (MIMO) systems for underground mine wireless communications in the 2.4 GHz band are investigated. To satisfy both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, two separate measurement campaigns are performed in a real L-shaped underground mine gallery; the first uses 4-elements beamforming conformal microstrip patch arrays (CMPA), while the second uses 4-elements beamforming Butler Network (BN-MIMO) by means of connecting a planar microstrip patch array to a Butler matrix. Due to its high radiation efficiency, the latter shows further performance for enhancing the channel propagation characteristics, and thus, for reducing the average path loss by about (2.2 dB, 5.1 dB) under (LOS, NLOS) conditions, respectively. Similarly, a reduction of (0.67 ns, 3.7 ns) in the RMS delay spread has been achieved to result in an additional gain of (4.6 MHz, 0.82 MHz) in the channel's coherence bandwidth. Furthermore, the orthogonal property of BN array radiation beams has led to a suppression of about (6%, 11%) in inter-subchannels correlations to boost (1.1 bit/s/Hz, 4.35 bit/s/Hz) in the channel capacity.

1. Yarkan, S., S. Guzelgoz, H. Arslan, and R. R. Murphy, "Underground mine communications: A survey," IEEE Communications Surveys & Tutorials, Vol. 11, No. 3, 125-142, 2009.
doi:10.1109/SURV.2009.090309

2. Rissafi, Y., L. Talbi, and M. Ghaddar, "Experimental characterization of an UWB propagation channel in underground mines," IEEE Trans. Antennas and Propagation, Vol. 60, No. 1, 240-246, Jan. 2012.
doi:10.1109/TAP.2011.2167927

3. Forooshani, A., S. Bashir, D. Michelson, and S. Noghanian, "A survey of wireless communications and propagation modeling in underground mines," IEEE Communications Surveys & Tutorials, Vol. 15, No. 14, 1524-1545, Nov. 2013.

4. Molisch, A. F., Wireless Communications, 2nd Ed., Wiley, 2011.

5. Ghaddar, M., M. Nedil, I. B. Mabrouk, and L. Talbi, "Multiple-input multiple-output beamspace for high-speed wireless communication in underground mine," IET Microwaves, Antennas & Propagation, Vol. 9, No. 13, Oct. 2015.

6. Nedil, M., T. A. Denidni, and L. Talbi, "Novel butler matrix using CPW multilayer technology," IEEE Transactions on Microwave Theory and Techniques, Vol. 54, No. 1, 499-507, Jan. 2006.
doi:10.1109/TMTT.2005.860490

7. Hansen, R. C., Phased Array Antennas, John Wiley and Sons, New York, 1997.

8. Berke, C., A. Yusuf, and R. Gabriel, "An 8 × 8 Butler matrix in 0.13-μm CMOS for 5-6-GHz multibeam applications," IEEE Transaction on Microwave Theory and Techniques, Vol. 59, No. 2, Feb. 2011.

9. Grau, A., J. Romeu, and F. De Flaviis, "On the diversity gain using a butler matrix in fading MIMO environments," Wireless Communications and Applied Computational Electromagnetics International Conference, 478-481, Apr. 2005.

10. Ben Mabrouk, I., L. Talbi, and M. Nedil, "Performance evaluation of a MIMO system in underground mine gallery," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 830-833, 2012.
doi:10.1109/LAWP.2012.2208260

11. Durgin, G., T. S. Rappaport, and H. Xu, "Measurements and models for radio path loss and penetration loss in and around homes and trees at 5.85 GHz," IEEE Transactions on Communications, Vol. 46, No. 11, 1484-1496, Nov. 1998.
doi:10.1109/26.729393

12. Forooshani, A., R. White, and G. Michelson, "Effect of antenna array properties on multipleinput- multiple-output system performance in an underground mine," IET Microwaves Antennas & Propagation, Vol. 7, No. 13, 1035-8725, 2013.
doi:10.1049/iet-map.2013.0102

13. Boutin, M., A. Benzakour, C. Despins, and E. Affes, "Radio wave characterization and modeling in underground mine tunnels," IEEE Transactions on Antennas and Propagation, Vol. 4, No. 5, 540-549, 2008.
doi:10.1109/TAP.2007.913144

14. Kang, M. and M. Alouini, "Capacity of MIMO Rician channels," IEEE Transactions on Wireless Communications, Vol. 5, No. 1, 112-122, 2006.
doi:10.1109/TWC.2006.1576535

15. Rappaport, T. S., Wireless Communications: Principle and Practice, 2nd Ed., Prentice Hall, PTR, NJ, USA, 2002.

16. Wang, Y., W. Lu, and H. Zhu, "Propagation characteristics of the LTE indoor radio channel with persons at 2.6GHz," IEEE Antennas and Propagation Letters, Vol. 12, 991-994, 2013.
doi:10.1109/LAWP.2013.2275811

17. Ruisi, H., Z. Zhangdui, A. Bo, G. Ke, C. Binghao, J. AIonso, and C. Briso, "Propagation channel measurements and analysis at 2.4GHz in subway tunnels," IET Microwaves, Antennas and Propagation, Vol. 7, No. 11, 934-941, 2013.
doi:10.1049/iet-map.2013.0159

18. Molisch, A. F., Wireless Communications, 2nd Ed., Wiley, 2011.

19. Cho, Y., J. Kim, W. Yang, and C. Kang, MIMO-OFDM Wireless Communications with MATLAB, John Wiley & Sons, 2010.
doi:10.1002/9780470825631

20. Ben Mabrouk, I., L. Talbi, and M. Nedil, "Performance evaluation of a MIMO system in underground mine gallery," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 830-833, 2012.
doi:10.1109/LAWP.2012.2208260

21. Malik, W. Q., "Spatial correlation in ultrawideband channels," IEEE Transactions on Wireless Communications, Vol. 7, No. 2, 60-610, Feb. 2008.
doi:10.1109/TWC.2008.060547

22. Telatar, I. E., "Capacity of multi-antenna Gaussian channels," AT&T Bell Lab Internal Tech. Memo., Oct. 1995.

23. Foschini, G. J. and M. J. Gans, "On limits of wireless communications in a fading environment when using multiple antennas," Wireless Personal Communications, Vol. 6, No. 3, 31-335, 1998.
doi:10.1023/A:1008889222784

Dr. Mohamad Ghaddar

Prof. Mourad Nedil

Dr. Larbi Talbi

Dr. Ismail Ben Mabrouk