Patent ID: 7986740

Claim:
A method for canceling a Doppler shift, multi-path propagation, delays, and long time selective fading influences of phase and/or amplitude modulated signals carried by Radio Frequency (RF) sub-carriers, without requirement of pilot signals, comprising: a) determining the number of m=2 n (n=1, 2, . . . ,) orthogonal sub-carriers f 1 , f 2 , . . . , f m , over which individual datum is transmitted in each communication channel; b) selecting pairs of Walsh functions from an m×m Walsh-Hadamard matrix, wherein each function is not selected more than once; c) partitioning each said signal to its I factor and Q factor whereas I=A sin φ of said signal and whereas Q =A cos φ of said signal, and coding each said I and Q factors of said signals by said pair functions; d) for each sub-carrier f i (i=1, 2, . . . ,m), allocating a corresponding phase φ i and amplitude A i , wherein the value of φ i and the value of A i are determined by the data that is transmitted, a digital modulation scheme or inverse spectral transformation, and signs of both corresponding elements taken from said pair Walsh functions; e) transmitting data with said corresponding phases and amplitudes over said sub-carriers; f) receiving all transmissions carried by said sub-carriers and obtaining the corresponding phases and amplitudes of all the received signals at frequency f i using spectral transformation; g) decoding said received signals by changing signs of I and Q factors of said received signals in accordance with corresponding elements from said pair functions used to decode said signals; h) separately summing the I and Q factors of received signals after changing signs of said I and Q factors of received signals, and dividing each of the summations of I and Q factors by m; and i) reconstructing said signal, using said divided I and Q factors, by calculating its phase whereas φ = arc ⁢ ⁢ tg ⁢ I Q and calculating its amplitude whereas A=√{square root over (I 2 +Q 2 )}.