Patent ID: 6952444

Claim:
A communication receiver, comprising: an input for receiving a modulated analog signal containing digital information; a front end unit operable for performing analog-to-digital conversion, for performing demodulation and for performing timing control, and further operable for producing a demodulated complex-valued digital signal from the modulated analog signal; a digital equalizer connected for receiving the demodulated complex-valued digital signal, comprising: a first filter operable for receiving the demodulated complex-valued digital signal, said first filter with adaptive coefficients where adaptation is according to the following formula: p n+1 [l]=p n [l]+Γ n ( s 2 [n ]) s 1 *[n−l]= 1, . . . , L where p n [l] is the l-th tap of the first filter after calculation of n outputs, p n [0]=1, s 1 [n] is the input sequence to the first filter, s 2 [n] is the output of the first filter, and Γ n (.) is a function whose parameters may depend upon a symbol index n; a second filter connected to the first filter and operable for reducing the amount of noise and inter-symbol interference in the demodulated complex-valued digital signal without the use of training data; and a symbol-to-bit converter connected to the second filter; wherein the second filter further comprises an M-tap FIR filter whose taps are adjusted according to the following formula: c n+1 [m]=c n [m]+φ n (s 5 [n])s 3 *[n−m]m=1, . . . , M where c n [m] is the m-th tap of the second filter after calculation of n outputs, s 3 [n] is the input sequence to the second filter, s 5 [n] is the sum of the output of the second filter and a decision feedback filter, and φ n ) is a complex-valued function, whose parameters may depend upon a symbol index n; and the decision feedback filter is an N-tap backward FIR filter whose taps are adjusted according to the following formula: d n+1 [i]=d n [i]+Ψ n (s 5 [n]) â*[n−i]i=1, . . . , N where d n [i] is the i-th tap of the decision feedback filter after calculation of n outputs, â[n] is a sequence of detected data, and Ψ n (.) is a complex-valued function, whose parameters may depend on the symbol index n.