OFDM (DMT) Bit and Power Loading for Unequal Error Protection

This paper proposes an algorithm that distributes bits according to different noise margin levels, thereby realizing unequal error protection (UEP). The new approach is based on a non-UEP allocation algorithm by Chow, Cioffi, and Bingham. The new algorithm is designed to be robust to non-stationary impulse noise and channel variations by integrating a new SNR-sorting scheme. Simulation results show that the highly protected bits are spread over a high number of carriers at low SNR, thereby ensuring that SNR variations due to non-stationary noise will not influence these carriers much. Additionally, narrow-band interference will not hit a large amount of important data.