Introduction

In order to aid vendors and operators in the development and deployment of new heterogeneous cellular networks (HCNs), and the refinement of existing procedures such as handover (HO) and radio resource management (RRM), network simulation, planning and optimization tools that are able to evaluate the overall performance of complex cellular networks are highly regarded. In this context, system-level simulations have become a widely adopted methodology. In system-level simulations, the elements and operations of a cellular network are modeled by computer software. This approach is usually simpler and cheaper than real implementation, and is more accurate and reliable than analytical modeling. The number of assumptions and simplifications made in system-level simulations is up to the software designer, but it is usually less than that of analytical modeling. System-level simulations can also model more complex cellular networks than analytical modeling. However, system-level simulations for modeling intricate procedures or getting statistically representative results of network performance usually require significant computing capabilities. As a result, in order to avoid prohibitive computational costs, a tradeoff between accuracy and complexity should be reached. In this line, the 3rd Generation Partnership Project (3GPP) provides guidelines on network simulations, and defines simulation procedures and parameters.