Superframe-based bit allocation algorithms for DMT systems

A superframe-based DMT transceiver system with multiple bit tables (SM-DMT) is proposed. This proposed system can be applied to either a frequency division multiplexed (FDM) DMT system or a time division multiplexed (TDM) DMT system. The latter system is also known as synchronized DMT (SDMT) systems. This paper shows how an SM-DMT system provides optimal performance in situations where either a FDM-based DMT system or a TDM-based DMT system may suffer from performance degradation. A bit allocation algorithm for SM-DMT systems is also presented. Simplified algorithms based on grouping and table-sharing are described to reduce the practical complexity requirement.