Method and apparatus for an equalizer based on viterbi algorithm

A method comprising:

• obtaining, by an equalizer based on Viterbi algorithm in a receiver in a communication link, for a first possible state (s) of a received sample at the current time step (k), log-likelihood ratio, Ilr, values Ilrold,min, Ilrold,max of a first transmitted bit (bj), wherein, the Ilr values Ilrold,min, Ilrold,max are respectively associated with a most likely state (s′min) and a less likely state (s′max) related to a received sample at a previous time step (k−1);
• determining, by the equalizer, based on path metrics and branch metrics corresponding to the received sample at the current time step (k);
• a first parameter related to a difference between likelihoods of the most likely state (s′min) and the less likely state (s′max);
• updating, by the equalizer, magnitude of the Ilr value Ilrold,min at least based on the Ilr value Ilrold,min, the Ilr value Ilrold,max, and the first parameter, to obtain an updated Ilr value Ilrold,updated.

A non-transitory computer readable medium storing instructions which, executed by a computer, cause the computer to perform

• obtaining for a first possible state (s) of a received sample at the current time step (k), log-likelihood ratio, Ilr, values Ilrold,min, Ilrold,max of a first transmitted bit (bj), wherein, the Ilr values Ilrold,min, Ilrold,max are respectively associated with a most likely state (s′min) and a less likely state (s′max) related to a received sample at a previous time step (k−1);
• determining based on path metrics and branch metrics corresponding to the received sample at the current time step (k);
• a first parameter related to a difference between likelihoods of the most likely state (s′min) and the less likely state (s′max);
• updating magnitude of the Ilr value Ilrold,min at least based on the Ilr value Ilrold,min, the Ilr value Ilrold,max, and the first parameter, to obtain an updated Ilr value Ilrold,updated.