Patent ID: 6944234

Claim:
A communication system comprising: an encoder encoding an input sequence to sequentially generate output codes X 0 , X 1 , . . . ; and a decoder decoding said output codes by a MLSD (Maximum Likelihood Sequence Detection) method with a trellis memory length being L, wherein said output code X k of said output codes X 0 , X 1 , . . . is determined based on said input sequence for k that is not equal to i(N+1) with i being any of natural number and with N being a natural number, and wherein said output code X i(N+1) of said output codes X 0 , X 1 , . . . are uniquely determined based on a subset of a set consisting of output codes X i(N+1)−L+1 , X i(N+1)−L+2 , . . . , X i(N+1)−1 of said output codes X 0 , X 1 , . . . , and wherein said subset includes output code X i(N+1)−L+1 of said output codes X i(N+1)−L+1 , X i(N+1)−L+2 , . . . , X i(N+1)−1 .