Analysis of Bus-Invert coding in the presence of correlations

The selection of the right low-power coding technique during the design of the interconnect architecture has a high potential. However, it requires the analysis and evaluation to be performed at high-levels of abstraction. Closed formulas to quantify the power reduction achieved by each low-power code are therefore highly desirable. Using a simplified Dual Bit Type model for the underlying signals, the current work provides closed formulas for calculating the transition activity of correlated DSP signals encoded with the Bus-Invert technique. It considers the effect of the temporal and spatial correlation present in typical DSP signals. The accuracy of the proposed formulas is validated with extensive simulations at the bit level.