Method and apparatus for decision feedback equalization with reduced convergence time

Claim 3

The method of claim 1, wherein step (c) includes the steps of: filtering the replica input signal s'(n) in a set of serially connected phase delay filters; multiplying a phase delayed output signal from each of the phase delay filters by a phase delayed version of one of the coefficients a' j (n) to generate a set of N product signals; and summing the N product signals to generate the replica transmitted signal x'(n).

Claim 4

The method of claim 2, wherein the transmitted signal x(n) results from transmission of the input signal s(n) through a transmission channel having a z-domain transfer function H(z) and a receive filter having a z-domain transfer function 1-1/z, and wherein the transfer function A(z) satisfies A(z)=H(z)[1-1/z].

Claim 5

A decision feedback equalization apparatus for performing multiple iterations of a blind mode decision feedback equalization on a transmitted signal x(n) resulting from transmission of an input signal s(n) through a channel having a z-domain transfer function A(z), said apparatus including: means for generating a replica input signal s'(n) during each of the iterations; means for generating a feedback coefficient a' 0 (n) in response to a feedback signal Ke(n)s'(n) during each of the iterations, where K is a convergence scaling factor; means for generating an error signal e(n) in response to the feedback coefficient a' 0 (n) during each of the iterations; and adaptive filter means for processing the replica input signal s'(n) to generate a replica transmitted signal x'(n) in response to a set of adaptively generated coefficients a' j (n), where j=1, 2, . . . , N, and N is an integer, and wherein the adaptive filter means includes a means for generating each of the coefficients a' j (n) in response to a feedback signal 2Ke(n)s'(n-j), where K is said convergence scaling factor.

Claim 6

A decision feedback equalization apparatus for performing multiple iterations of a blind mode decision feedback equalization on a transmitted signal x(n) resulting from transmission of an input signal s(n) through a channel having a z-domain transfer function A(z), said apparatus including: means for generating a replica input signal s'(n) during each of the iterations; means for generating a feedback coefficient a' 0 (n) in response to a feedback signal Ke(n)s'(n) during each of the iterations, where K is a convergence scaling factor; means for generating an error signal e(n) in response to the feedback coefficient a' 0 (n) during each of the iterations; and adaptive filter means for processing the replica input signal s'(n) to generate a replica transmitted signal x'(n) in response to a set of adaptively generated coefficients a' j (n), where j=1, 2, . . . , N, and N is an integer, and wherein the adaptive filter means includes a means for generating each of the coefficients a' j (n) in response to a feedback signal 2Ke(n)s'(n-j), where K is said convergence scaling factor.

Claim 7

The apparatus of claim 4, wherein the adaptive filter means includes: a set of N serially connected phase delay circuits, for receiving the replica input signal s'(n) and generating a set of N phase-delayed replica input signals in response to said replica input signal s'(n); a set of N coefficient updating and multiplication circuits, each connected to an output of a different one of the phase delay circuits, wherein each of the coefficient updating and multiplication circuits includes a circuit for generating a different one of the coefficients a' j (n), and a multiplication circuit for multiplying one of the phase-delayed replica signals by one of the coefficients a' j (n).

Claim 8

The apparatus of claim 5, wherein the adaptive filter means also includes: a means for combining the outputs of the coefficient updating and multiplication circuits to generate the replica transmitted signal x'(n).

Claim 9

The apparatus of claim 5, wherein the transmitted signal x(n) results from transmission of the input signal s(n) through a transmission channel having a z-domain transfer function H(z) and a receive filter having a z-domain transfer function 1-1/z, and wherein the transfer function A(z) satisfies A(z)=H(z)[1-1/z], and wherein each of the N serially connected phase delay circuits has a z-domain transfer function equal to 1/z.

Claim 10

A decision feedback equalization apparatus for performing multiple iterations of a blind mode decision feedback equalization on a transmitted signal x(n) resulting from transmission of an input signal s(n) through a channel having a z-domain transfer function A(z), said apparatus including: means for generating a replica input signal s'(n) during each of the iterations; means for generating an error signal e(n) during each of the iterations; and means for generating an updated vector A'(n) of replica coefficient signals a' j (n) during each of the iterations, where A'(n)=A'(n-1)+KWS'(n-1)e(n-1), A'(n) is a transposed vector [a' 0 (n) a' 1 (n) . . . a' N (n)] T of said replica coefficient signals a' j (n), with j=0, 1, . . . , N, A'(n-1) is a transposed vector [a' 0 (n-1) a' 1 (n-1) . . . a' N (n-1)] T of coefficient signals generated during an iteration immediately preceding said each of the iterations, S'(n-1) is a transposed vector [s'(n) s'(n-1) . . . s'(n-N)] T of said replica input signal s'(n) and phase-delayed replica input signals s'(n-m), where m=1, 2, . . . ,N, where e(n-1) is an error signal generated during an iteration immediately preceding said each of the iterations, K is a convergence scaling factor, and W is a diagonal (N+1)×(N+1) matrix whose first diagonal coefficient signal has a value equal to one, whose other diagonal coefficient signals each have a value equal to two, and whose off-diagonal coefficient signals each have a value equal to zero.

Claim 11

A decision feedback equalization apparatus for performing multiple iterations of a blind mode decision feedback equalization on a transmitted signal x(n) resulting from transmission of an input signal s(n) through a channel having a z-domain transfer function A(z), said apparatus including: means for generating a replica input signal s'(n) during each of the iterations; means for generating an error signal e(n) during each of the iterations; and means for generating an updated vector A'(n) of replica coefficient signals a' j (n) during each of the iterations, where A'(n)=A'(n-1)+KWS'(n-1)e(n-1), A'(n) is a transposed vector [a' 0 (n) a' 1 (n) . . . a' N (n)] T of said replica coefficient signals a' j (n), with j=0, 1, . . . , N, A'(n-1) is a transposed vector [a' 0 (n-1) a' 1 (n-1) . . . a' N (n-1)] T of coefficient signals generated during an iteration immediately preceding said each of the iterations, S'(n-1) is a transposed vector [s'(n) s'(n-1) . . . s'(n-N)] T of said replica input signal s'(n) and phase-delayed replica input signals s'(n-m), where m=1, 2, . . . ,N, where e(n-1) is an error signal generated during an iteration immediately preceding said each of the iterations, K is a convergence scaling factor, and W is a diagonal (N+1)×(N+1) matrix whose first diagonal coefficient signal has a value equal to one, whose other diagonal coefficient signals each have a value equal to two, and whose off-diagonal coefficient signals each have a value equal to zero.

Claim 12

The apparatus of claim 8, wherein the means for generating the error signal e(n) includes a feedback loop for generating means for generating said error signal e(n) in response to said replica coefficient signal a' 0 (n) during said each of the iterations.

Claim 13

The apparatus of claim 9, also including a means for generating a replica transmitted signal x'(n) during said each of the iterations by processing the phase-delayed replica input signals s'(n-m) and a subset a' m (n) of the replica coefficient signals, where m=1, 2, . . ., N.