A Coding Approach to Improve the Energy Efficiency of Approximate NoCs

In NoC-based multi-core systems, the communication subsystem accounts for a significant fraction of the energy consumption. Traditional NoCs guarantee error-free data transfer at the expenses of limiting the hardware optimization possibilities. However, in various applications, such as multimedia processing and machine learning, inaccurate outputs within an acceptable variance is tolerable. Recently, approximate NOCs have been proposed as a viable solution to exploit the trade off between the energy efficiency with data approximation. In this context, we propose two coding techniques. First, a combined memory-less integer-value encoding is proposed to reduce the integer-value deviation in the body flit of the approximate NOCs; and second, a crosstalk avoidance code (CAC) to guarantees the exact transmission of the head flit. Our technique improves the energy consumption of the approximate NOCs remarkably and does not introduces any performance or area penalty. Experimental results using a 65nm commercial technology asses the advantages of the proposed coding approach versus conventional transmission. proposed coding in real scenarios.