WiMAX has attracted a lot of attention recently in the telecommunication community including researchers, product developers and service providers. Numerous papers have been published on various design issues of WiMAX networks. Since the issues being discussed are usually ahead of the product availability, most of these studies require simulation. It is important to have some common features among these models so that their results can be compared. The Application Working Group at the WiMAX Forum, therefore, has developed a standard simulation methodology that describes the key features to be simulated, the method of simulating these features and various parameter values to be used. This system level methodology has been used in several public and commercial WiMAX simulation models. This paper presents a summary of the simulation methodology and discusses the key issues and common mistakes in simulating various features of network configuration, physical layer, media access control (MA...