A transmitting device configured to obtain a message to be transmitted; map the obtained message onto a two-dimensional 2n-symbol constellation to obtain a sequence of discrete constellation symbols, where n is an odd number not less than 3. A receiving device configured to receive a sequence of noisy discrete constellation symbols; demap the sequence of noisy discrete constellation symbols to output data using a two-dimensional 2n-symbol constellation, where n is an odd number not less than 3.