An improved method of maximum likelihood decoding algorithms using the most reliable basis based on a order relation among binary vectors

摘要

Several reliability based maximum likelihood decoding (MLD) algorithms of linear block codes have been widely studied. These algorithms efficiently search the most likely codeword, using the most reliable basis of generator matrix whose leftmost k (the dimension of code) columns are the most reliable and linearly independent. In this paper, several sufficient conditions for eliminating unnecessary candidate codewords or their metrics computations are derived for MLD algorithms using the most reliable basis by utilizing a order relation among binary vectors. Under the certain assumption of generation order of candidate codewords, we devise an adaptive implementation of the derived conditions. Consequently, the MLD algorithm employing the derived conditions reduces the number of generated candidate codeword and of real number operations, compared to a conventional MLD using the MRB without the degradation in error performance.