US Patent 7161991 Multi-dimensional fractional number of bits modulation scheme

A method of encoding information bits of a communication signal for a communication system (10) is provided. The method includes decomposing the communication signal having a corresponding M1-ary modulation constellation into a M2-ary constellation, and a M3-ary constellation to generate one or more symbols Si. The one or more symbols Si are mapped using a bit-to-symbol table to generate an encoded communication signal. Decoding methods are also provided for uncoded modulation and trellis coded modulation (TCM). A transmitter (20) comprising an encoder (12) for performing TCM that is capable of transmitting a fractional number of information bits per transmitted symbol is also provided.