This paper presents analysis results relative to an underground MIMO channel. Measurement campaigns were conducted in a former gold mine at a center frequency of 5.8 GHz under Line-Of-Sight (LOS) scenario. Extracted data have been processed to obtain the relevant statistical parameters of the channel. The resulting propagation behavior differs from frequently encountered in more typical indoor environments, such as offices and corridors. Indeed, the path loss exponent is less than 2 in MIMO configuration due to the large number of scatters that increase the received power when compared to the free-space case. Moreover, there has been a significant increase in spectral efficiency, when using MIMO technique. Hence, according to calculated statistical parameters, wireless link performance is improved through the use of the MIMO scheme. All in all, multi antenna systems present an ideal alternative for future underground communication systems.
2. Shin, H. and J. H. Lee, "Capacity of multiple-antenna fading channels: Spatial fading correlation, double scattering, and keyhole," IEEE Transactions on Information Theory, Vol. 49, 2636-2647, Oct. 2003.
3. Foschini, G. J. and M. J. Gans, "On limits of wireless communications in a fading environment," Wireless Pers. Commun., Vol. 6, 311-335, 1998.
4. Tarokh, V., N. Seshadri, and A. R. Calderbank, "Space-time codes for high data rate wireless communication: Performance criterion and code construction," IEEE Transactions on Information Theory, Vol. 44, 744-765, Mar. 1998.
5. Yu, K. , M. Bengtsson, B. Ottersten, D. McNamara, P. Karlsson, and M. Beach, "Modeling of wide-band MIMO radio channels based on NLoS indoor measurements," IEEE Transactions on Vehicular Technology, Vol. 53, 655-665, May 2004.
6. Molisch, A. F., M. Steinbauer, M. Toeltsch, E. Bonek, and R. S. Thoma, "Capacity of MIMO systems based on measured wireless channels," IEEE Journal on Selected Areas in Communications, Vol. 20, 561-569, Apr. 2002.
7. Boutin, M., A. Benzakour, C. L. Despins, and S. Affes, "Radio wave characterization and modeling in underground mine tunnels," IEEE Transactions on Antennas and Propagation, Vol. 56, 540-549, Feb. 2008.
8. Jakes, W. C., Microwave Mobile Communications, Wiley, New York, 1974.
9. Tepedelenlioglu, C. , A. Abdi, and G. Giannakis, "The ricean K factor: Estimation and performance analysis," IEEE Transactions on Wireless Communications, Vol. 2, No. 4, 799-810, 2003.
10. Khan, I. and P. S. Hall, "Experimental evaluation of MIMO capacity and correlation for narrowband body-centric wireless channels," IEEE Transactions on Antennas and Propagation, Vol. 58, No. 1, 195-202, Jan. 2010.
11. Ben Mabrouk, I., L. Talbi, B. Mnasri, M. Nedil, and N. Kandil, "Experimental characterization of a wireless MIMO channel at 2.4 GHz in underground mine gallery," Progress In Electromagnetics Research Letters, Vol. 29, 97-106, 2012.
12. Sarris, I. and A. R. Nix, "Ricean K-factor measurements in a home and an office environment in the 60 GHz band," Mobile and Wireless Communications Summit, 2007.
13. Ben Mabrouk, I., L. Talbi, M. Nedil, and K. Hettak, "MIMO-UWB channel characterization within an underground mine gallery," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 10, 4866-4874, Jul. 2012.
14. Karedal, J., S. Wyne, P. Almers, F. Tufvesson, and A. F. Molisch, "A measurement-based statistical model for industrial ultra-wideband channels," IEEE Transactions on Wireless Communications, Vol. 6, 3028-3037, Aug. 2007.
15. Telatar, I. E., "Capacity of multi-antenna Gaussian channels," European Trans. Telecommun. (ETT), Vol. 10, No. 6, 585-595, Nov./Dec. 1999.
16. Maaref, A. and S. Aissa, "On the capacity statistics of MIMO Ricean and rayleigh fading channels," IEEE International Conference on Communications,, Vol. 9, 4167-4172, Jun. 2006.
17. Mabrouk, I. B., L. Talbi, M. Nedil, Y. Coulibaly, and T. A. Denidni, "Effect of antenna directivity on performance of multipleinput multiple output systems in an underground gold mine," IET Microw. Antennas Propag., Vol. 6, No. 5, 555-561, Apr. 12, 2012.