Data Encoding Schemes in Networks on Chip

An ever more significant fraction of the overallpower dissipation of a network-on-chip (NoC) based systemon-chip (SoC) is due to the interconnection system. In fact, astechnology shrinks, the power contribute of NoC links starts tocompete with that of NoC routers. In this paper, we proposethe use of data encoding techniques as a viable way to reduceboth power dissipation and energy consumption of NoC links.The proposed encoding scheme exploits the wormhole switchingtechniques and works on an end-to-end basis. That is, flits areencoded by the network interface (NI) before they are injectedin the network and are decoded by the destination NI. Thismakes the scheme transparent to the underlying network sincethe encoder and decoder logic is integrated in the NI and nomodification of the routers architecture is required. We assessthe proposed encoding scheme on a set of representative datastreams (both synthetic and extracted from real applications)showing that it is possible to reduce the power contribution ofboth the self-switching activity and the coupling switching activityin inter-routers links. As results, we obtain a reduction in totalpower dissipation and energy consumption up to 37% and 18%,respectively, without any significant degradation in terms of bothperformance and silicon area.