Advanced simulation tools have taken a lot of attention for development and analysis of new and existing protocols and technologies in wireless communications. The huge amount of information, protocols and techniques to be analysed make however their implementation difficult in one simulator. It is thus of paramount importance to define a common interface between the different layers in order to simplify the implementation task but guaranteeing also the confidence of the obtained results. This paper provides a complete specification of the system level simulation envisaged for Beyond 3rd Generation (B3G) systems. The main idea of this paper is to explain how we could extract information from the link level simulation and to implement them in the system level simulation. Two particular cases are considered for the proof of concept in this work. The first one concerns the Spatial Division Multiple Access (SDMA) technique using positioning information. The second one concerns the use of the cooperative communications to improve the quality of service at the cell border.