Patent ID: 7187728

Claim:
A method of determining coding parameters of a convolution decoder for improving coding gain in a receiver for receiving carrier signals modulated with sixteen different digital states, comprising the step of: a) using a 2 ASK/8 PSK coding; b) selecting a deconvolution code for the decoder and determining all possible code word sequences with a free distance of the deconvolution code; c) forming possible mappings by allocating a partial set of 2 ASK/8 PSK channel bits into subsets; and d) selecting the possible mappings in which, after determining optimal radii of two amplitudes for each possible mapping, a minimal Euclidean distance produced between two possible subset becomes maximal thereby improving the coding gain, the optimal radii denoted by ac and c being determined by the following equations: 8( ac ) 2 +8 c 2 =16 n·d 11 2 +m·d 01 2 +k·d 10 2 =(2 ac ) 2 for 2 ac≦√{square root over (c 2 +(ac) 2 )} and n·d 11 2 +m·d 01 2 +k·d 10 2 =c 2 +( ac ) 2 for 2 ac≧√{square root over (c 2 +(ac) 2 )}, in which d 11 is the minimal geometric distance of a subset transition 00→11 and n is the number of these transitions in the considered code word sequence, d 01 is the minimal geometric distance of a subset transition 00→01 and m is the number of these transitions in the considered code word sequence and d 10 is the minimal geometric distance of a subset transition 00→10 and k is the number of these transitions in the considered code word sequence.