Patent ID: 7545871

Claim:
An N (N>1)-point discrete multi-tone (DMT) system, comprising: a transmitting end, said transmitting end having an inversed discrete Fourier transform (IDFT) operator accepting complex-valued symbols X k (k=0, 1, . . . , N−1) as input for modulation onto x n (n=0, 1, . . . , N−1) subchannels of said DMT system, said IDFT operator being characterized by equation: x n = 1 N ⁢ ∑ k = 0 N - 1 ⁢ X k · W N - kn , n = 0 , 1 , … ⁢ , N - 1 where W N = ⅇ - j ⁢ 2 ⁢ π N ; and a receiving end, said receiving end having a discrete Hartley transform (DHT) operator for demodulation y n (n=0, 1, . . . , N−1) subchannels of said DMT system, and a DHT-based frequency-domain equalizer (FEQ) operator following said DHT operator for equalization, said DHT operator being characterized by equation: H ~ k = ∑ n = 0 N - 1 ⁢ y n · cas ⁡ ( 2 ⁢ π ⁢ ⁢ nk / N ) , k = 0 , 1 , … ⁢ , N - 1 , where cas(2πnk/N)=cos(2πnk/N)+sin(2πnk/N); and said DHT-based FEQ operator performing three operations: filtering, error estimation, and coefficient updating, said filtering operation being characterized by equation: [ Y ^ k , R Y ^ k , I ] = [ S k C k - C k S k ] · [ H ~ k H ~ N - k ] , k = 0 , 1 , … ⁢ , N 2 - 1 , ⁢ Y ^ k = Y ^ k , R + j ⁢ ⁢ Y ^ k , l said error estimation operation being characterized by equation: E k = X k - Y ^ k , k = 0 , 1 , … ⁢ , N 2 - 1 , and said coefficient updating operation being characterized by equation: [ S k ⁡ ( n + 1 ) C k ⁡ ( n + 1 ) ] = [ S k ⁡ ( n ) C k ⁡ ( n ) ] + μ k · M ⁡ ( H ~ k , H ~ N - k , E k ) , ⁢ k = 0 , 1 , … ⁢ , N 2 - 1 , where M is a matrix operator involving E k , {tilde over (H)} k and {tilde over (H)} N-k , {tilde over (H)} k and {tilde over (H)} N-k are the k-th and (N-k)-th subchannels output from said DHT operator, X k is the training symbol of the k-th subchannel of said DMT system, Ŷ k is the k-th subchannel output from said DHT-based FEQ operator, μ k is the updating step-size of said DHT-based FEQ operator, and S k and C k are coefficients.