Coding method and use of a receiver with a convolutional decoder

1. 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.

2. The method according to claim 1 , characterized by the fact that the subsets are chosen by the following equations:

d 11 =d 1 =c−ac

for

c−ac≦ac·√{square root over (2)}

or

d 11 =d 1 =ac·√{square root over (2)}

for

ac ·√{square root over (2)} ≦c−ac

and

d 01 =d 10 =d 0 =ac √{square root over ((1−√{square root over (0.5)}))}.

3. The method according to claim 2 , characterized by the fact that, for determining the optimal radii, it is assumed that:

d 1 ≦√{square root over (2)} ·d 0 .