Bit swapping and dynamic rate adjustment for multicarrier transmission in a digital subscriber line system

摘要

Bit swapping and dynamic rate adjustment in a multicarrier transmission system, such as a digital subscriber line (DSL) system using discrete multitone (DMT) transmission, are described that take the non-uniform variation of signal-to-noise ratios for various constellation sizes into account. The bits are distributed such that a probability of error is uniformly distributed among sub-channels, thus maintaining a bit error rate. Furthermore, the transmit scaling factors at the transmitter are optimized to provide more precise compensation of sub-channel variation. In addition, the bit swapping and dynamic rate adjustment techniques take into account maximum and minimum bits per sub-channel requirements.