We present a performance-oriented refinement approach that refines a perfectly synchronous communicationmodel onto Network-on-Chip (NoC) communication. We first identify four basic forms of NoC process interaction patterns at the process level, namely, producer-consumer, peers, client-server, and multicast. We propose a threestep top-down refinement method: channel refinement, protocol refinement and channel mapping. For the producer-consumer pattern, we describe it in detail. In channel refinement, we deal with interfacing multiple clock domains and use a stochastic process to model channel delay and jitter. In protocol refinement, we show how to refine communication towards application requirements such as reliability and throughput. In channel mapping, we discuss channel convergence and channel merge arising from channel overlapping. All the refinements have been conducted and validated as an integral design phase towards implementation in ForSyDe, a formal system-level design methodology based on a synchronous model of computation.