A priori uncertainty 1 Approximation 1 Approximation algorithms 1 Communication channels (information theory) 1 Communications channels 1 Direct conversion receivers 1 Estimation algorithm 1 Fading multipath channels 1 Least squares approximations 1 Least-squares- methods 1 MIMO 1 Parameter estimation 1 Priori uncertainty 1 Rayleigh fading 1 Receiving antennas 1 SISO 1 Signal receivers 1 Signal reception 1 a priori uncertainty 1 approximation 1 direct conversion receiver estimation 1 least squares method 1