On designing an efficient numerical-based forbidden pattern free crosstalk avoidance codec for reliable data transfer of NoCs

• A general Algorithm for Generating FPF-based Numerical systems called (AGFN) is proposed.
• n efficient coding mechanism called Summation-based-Subtracted-Added-Penultimate (S2AP) is proposed to alleviate crosstalk faults in NoC wires.
• It is proved that S2AP generates Triplet Opposite Direction (TOD)-free code words.
• An algorithm for mapping data words to FPF code words is provided using S2AP.

Inter-wire coupling capacitances can lead to crosstalk fault that is strongly dependent on the transition patterns appearing on the wires. These transition patterns can cause mutual influences between adjacent wires of NoCs and as a result threaten the reliability of data transfer seriously. To increase the reliability of NoCs against the crosstalk fault, Forbidden Pattern Free (FPFs) codes are used. To generate FPF codes, numerical systems are among the overhead-efficient mechanisms. The algorithms of numerical systems have direct effect on the amounts of the codec overheads including power consumption, area occupation and performance of NoCs. To find an overhead-efficient numerical system, this paper proposes an Algorithm for Generating FPF Numerical systems (AGFN). AGFN can provide a tradeoff for designers in selecting overhead-efficient FPF numerical systems. Using this algorithm, collection of Fibonacci-based and non-Fibonacci-based numerical systems can be generated. Then, using AGFN, non-Fibonacci-based FPF numerical system called Summation-based-Subtracted-Added-Penultimate (S2AP) is generated. Experimental results indicate that S2AP not only reduces the worst crosstalk effects by completely removing the Triplet Opposite Direction (TOD) transitions, but also it can significantly improve power consumption, area occupation and critical path overheads of codec with respect to the other state-of-the-art FPF codes.