Multi-dimensional space gray maps for multi-dimensional phase modulation as applied to LDPC (low density parity check) coded modulation

摘要

Multi-dimensional space gray maps for multi-dimensional phase modulation as applied to LDPC (Low Density Parity Check) coded modulation. A novel approach is provided within LDPC coded modulation communication systems that employ multi-dimensional phase modulation, using m-D (multi-dimensional) Gray code maps, to provide for improved performance when compared to communication systems employing 1-D (single-dimensional) Gray code maps. This approach can generate all possible m-D Gray code maps for a 2m-D M PSK modulation system. For example, all of the 2-D Gray code maps may be generated for a communication system using 4-D 8 PSK modulation system (where m=2, and M=8). A variety decoding processing approaches may be employed to perform LDPC coded modulation decoding of multi-dimensional space Gray code mapped signals. The slightly increased decoding complexity (when compared to decoding 1-D Gray code mapped signals) is the computation of symbol metrics and their decomposition to bit metrics. <IMAGE>