Sparse coding blind source separation through Powerline [3]

Without multiplexing, Powerline (PL) can support the concept of smart sensor web broadcasting of an N-sensors-to-single-owner (N-to-1) for household/stadium/mall/metro/city surveillance. In order to make the single user scenario feasible, the underdetermined blind source separation (BSS) problem x(k) = 〈^⇀a, ^⇀s(k)〉 + n(k) has to be solved so that only inner product time series signal x(k) is known. Our contribution is based on the understanding that the finite alphabet property of the binary sources ^⇀s(k) can resolve the underdetermined PL BSS case. For example, the alphabet of two binary sources consists of four states (1 1, 1 -1, -1 1, -1 -1), which mixing vector ^⇀a and noise n(k) will spread in the mixed signal x(k), around the four centroids. We apply self-organizing maps to compute centroids from which the impulse response vector ^⇀a is determined. Then, the source vector ^⇀s(k) is recovered using the standard LMS method. Published by Elsevier Science B.V.