Histogram-Based Estimation of CIR Entropy for Multipath Propagation Environments

The paper considers a problem of accurate estimation of information entropy of wireless channel parameters for finite-size samples. Of a particular interest is the entropy of the Channel Impulse Response (CIR) in multipath environments. Multipath propagation characterized by a variety of signal paths due to random reflections, diffraction and scattering, induces a significant uncertainty in wireless channels, which affects the signal quality and system performance. We propose a new method for estimating the differential entropy of basic channel parameters, such as the multipath delay and amplitude of partial waves, using a histogram-based approach. An influence of the propagation environment parameters on the channel uncertainty is analyzed through a computer simulation, and the principal tradeoffs associated with the entropy estimation are identified. Our results provide an insight on the performance gain of CIR-based techniques in relation to the tasks of physical layer security.