Sequence estimation method and sequence estimator

A sequence estimation method for estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a list output Viterbi algorithm to decide one or a plurality of survivors for each state of a Viterbi algorithm including one or more states, the method comprising:

• a first comparison step for dividing 2U−1 (U is an integer larger than 2) of inputs into higher 2U−2 and lower 2U−2 according to a predetermined selection order and outputs the higher selection output;
• a second comparison steps for dividing 2U−1 (U is an integer larger than 2) of inputs into higher 2U−2 and lower 2U−2 according to a predetermined selection order and outputs the lower selection output;
• a third comparison step for receiving the higher selection output of the first comparison step and the lower selection output of the second comparison step, and dividing 2U−1 of inputs into higher 2U−2 and lower 2U−2 according to the selection order and output a higher selection output and a lower selection output;
• and
• a fourth comparison step for receiving the lower selection output of the first comparison step and the higher selection output of the second comparison step, and dividing 2U−1 of inputs into higher 2U−2 and lower 2U−2 according to the selection order and outputs a higher selection output and a lower selection output,
• wherein the method compares 2U input information of survivors and/or of path-metrics in the first and the second comparison steps as 2U−1 first input information and 2U−1 second input information, respectively, and selects 2U−1 survivors and/or 2U−1 of path-metrics from the third and the fourth comparison steps, respectively, as a higher order selection outputs according to a predetermined selection order.

A sequence estimation apparatus for estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a list output Viterbi algorithm to decide one or a plurality of survivors for each state of a Viterbi algorithm including one or more states, the apparatus comprising:

• a first metric calculator for calculating a metric using the received signal and its estimated value;
• a second metric calculator for calculating a metric using a filtering result obtained via a matching filter;
• and
• a metric combinor for weighted-summing metrics calculated by the first and the second metric calculators based on a characteristic of the channel.

A sequence estimation apparatus for estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a list output Viterbi algorithm to decide one or a plurality of survivors for each state of a Viterbi algorithm including one or more states, the apparatus comprising:

• a first metric calculator for calculating a metric using the received signal and its estimated value;
• a second metric calculator for calculating a metric using a filtering result obtained via a matching filter;
• and
• a metric selector for selecting a metric calculated by the first and the second metric calculator based on a characteristic of the channel.

A sequence estimation apparatus for estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a list output Viterbi algorithm to decide one or a plurality of survivors for each state of a Viterbi algorithm including one or more states, the apparatus comprising:

• a first comparator for dividing 2U−1 (U is an integer larger than 2) of inputs into higher 2U−2 and lower 2U−2 according to a predetermined selection order and outputs the higher selection output;
• a second comparator for dividing 2U−1 (U is an integer larger than 2) of inputs into higher 2U−2 and lower 2U−2 according to a predetermined selection order and outputs the lower selection output;
• a third comparator for receiving the higher selection output of the first comparator and the lower selection output of the second comparator, and dividing 2U−1 of inputs into higher 2U−2 and lower 2U−2 according to the selection order and output a higher selection output and a lower selection output;
• and
• a fourth comparator for receiving the lower selection output of the first comparator and the higher selection output of the second comparator, and dividing 2U−1 of inputs into higher 2U−2 and lower 2U−2 according to the selection order and outputs a higher selection output and a lower selection output,
• wherein the apparatus compares 2U input information of survivors and/or of path-metrics in the first and the second comparator as 2U−1 first input information and 2U−1 second input information, respectively, and selects 2U−1 survivors and/or 2U−1 of path-metrics from the third and the fourth comparator, respectively, as a higher order selection outputs according to a predetermined selection order.

The sequence estimation method comprising:

• estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a Viterbi algorithm, wherein the Viterbi algorithm is a list output Viterbi algorithm that decides one or a plurality of survivors for each state of the Viterbi algorithm including one or more states;
• a plurality of metric calculation steps performed on the received signal and the channel;
• determining a branch metric based on the received signal, a channel characteristic, and a branch selection signal;
• and
• generating a branch metric output signal,
• wherein determining the branch selection metric is based on one of a square metric and a modified metric according to the branch selection signal.

The sequence estimation method comprising:

• estimating a transmitted signal sequence transmitted from a transmission side based on a characteristic of a received signal and a channel using a Viterbi algorithm, wherein the Viterbi algorithm is a list output Viterbi algorithm that decides one or a plurality of survivors for each state of the Viterbi algorithm including one or more states;
• a plurality of metric calculation steps performed on the received signal and the channel;
• determining a branch metric based on the received signal, a channel characteristic, and a branch selection signal;
• and
• generating a branch metric output signal,
• wherein the branch selection signal is determined by:
• receiving the channel characteristic;
• calculating a residual ISI power;
• calculating a residual correlation power;
• and
• comparing the residual ISI power and the residual correlation power to determine the branch selection signal.