Statistical Analysis of Cascaded Multipath Fading Channels

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Zhong Zheng Name of the doctoral dissertation Statistical Analysis of Cascaded Multipath Fading Channels Publisher School of Electrical Engineering Unit Department of Communications and Networking Series Aalto University publication series DOCTORAL DISSERTATIONS 209/2015 Field of research Communications Engineering Manuscript submitted 8 May 2015 Date of the defence 17 December 2015 Permission to publish granted (date) 13 November 2015 Language English Monograph Article dissertation (summary + original articles) Abstract In cellular communication systems, one of the prominent impairments due to the wireless channel is the multipath fading. In this thesis, we study the multipath effects, particularly in the so-called cascaded fading channels. These channel models are useful when characterizing the indoor signal propagation, time-reversal transmission, and the rank deficiency due to insufficient scattering in multiantenna communications.In cellular communication systems, one of the prominent impairments due to the wireless channel is the multipath fading. In this thesis, we study the multipath effects, particularly in the so-called cascaded fading channels. These channel models are useful when characterizing the indoor signal propagation, time-reversal transmission, and the rank deficiency due to insufficient scattering in multiantenna communications. Thesis focuses on the statistical performance metrics of wireless systems. More precisely, in single-antenna transmission, we analyze the received signal distribution via moment-based approximation in presence of correlated cascaded channels. Using these results, the impact of channel correlation and number of scatterers are investigated for the cascaded Nakagami-m channels. Furthermore, the signal distribution of the cascaded Rician channel is used to construct a test statistics for a blind time-reversal detector. In the presence of a point target embedded in the multipath scattering, we show by Monte Carlo simulation that the proposed detector outperforms the existing detectors. In multi-antenna communications framework we consider information theoretic limits for the cascaded Rayleigh MIMO channels. In the ergodic channel, we obtain a lower bound for the ergodic mutual information and deduce a rate scaling law using a recent result from the random matrix theory. For the non-ergodic channel, we study the outage probability by establishing the central limit theorem for the linear spectral statistics of the channel matrices. This result also motivates us to construct a simple approximation for the fundamental tradeoff between diversity gain and multiplexing gain of the MIMO channel at realistic SNR levels.