Communication patterns describe simple and elegant structured interactions
in communication based applications. They are used in many parallel computing architectures
of parallel algorithms, data exchange protocols and web-services. Communication
patterns help programmers to design more efficient, structured, modular and
understandable architectures, but they do not provide any automatic code validation.
We study this problem using global session types, a type theory that describes structured
interactions from a global point of view. We then augment the syntax of global types
with parameters that abstract the number of participants and an iterative construct that
builds instances of parameterised communication patterns. Our formal system allows
programmers to represent parameterised communication patterns by global types and
then validate the code by type-checking.