An Adaptive Dictionary Encoding Scheme for SOC Data Buses

Tiehan Lv, Wayne H. Wolf, Jörg Henkel, Haris Lekatsas

Abstract: As bus lengths on multi-hundred-million transistor SOCs (systems-on-a-chip) grow and as inter-wire capacitances of sub-0.1 /spl mu/m technologies increase, the resulting high switching capacitances of buses (and interconnects in general) have a non-negligible impact on the power consumption of a whole SOC. In this paper, we address this problem by introducing our bus encoding technique 'ADES' that minimizes the power consumption of data buses through a dictionary-based encoding technique. We show that our technique saves between 18% and 40% of bus energy compared to the non-encoded cases using a large set of (freely-accessible) real-world applications. Furthermore, we compare our technique to the best-known data bus encoding techniques to date and show that it exceeds all of them in energy savings for the same set of applications. The additional hardware effort for our bus en/decoder is thereby very small.