Explicit Constructions of Memoryless Crosstalk Avoidance Codes via C-transform

One of the main problems in deep sub-micron designs of high speed buses is the propagation delay due to the crosstalk effect. To alleviate the crosstalk effect, there are several types of crosstalk avoidance codes proposed in the literature. In this technical brief, we develop explicit constructions of two types of memoryless crosstalk avoidance codes: forbidden overlap codes (FOCs) and forbidden transition codes (FTCs). Our constructions for both FOCs and FTCs have the largest set of codewords. To the best of our knowledge, this is the first explicit construction of a FOC that has the largest set of codewords. Our approach is based on the C-transform developed for routing optical packets in optical queues. We show such an approach can also be used for constructing limited-weight No Adjacent Transition (NAT) codes. keywords: crosstalk, bus encoding, Zeckendorf’s theorem