Intra-Flit Skew Reduction for Asynchronous Bypass Channel in NoCs

Abstract

Various novel NoC designs attempt to improve network throughput and latency by leveraging upon asynchronous bypass and specialized clock routing. The performance of such architectures is limited by the skewing of signal transitions on the bit-lines of link due to cross talk noise. This work proposes a two-step technique: TransSync-RecSync, to eliminate packet errors resulting from inter-bit-line transition skew. TransSync preemptively adds delay to bits in a flit before they are transmitted to overcome skewing of transitions on link while RecSync de-skews the bits at the receiving end by delaying all the transitions by the same amount as the maximum skew on the bus. The approach adds minimally to router complexity and involves no wire overhead. The proposed scheme when employed to augment a NoC design with asynchronous bypass channel was found to improve the average network latency by 38%.