Bit-Significances of Source-Coded Data: Analysis and Applications

The Logarithmic Bit-Significance Ratio (S-value) is a universal measure to quantify the significances of the bits in a communication system. We define the S-value and discuss relations to the well-known L-values that are used for soft-in/soft-out decoding at the receiving end. We argue that the S-values are the transmitter-based counterpart of the L-values, and we motivate the idea of soft-in/soft-out data processing at the transmitter by demonstrating practical benefits in a simple digital communication system.