A System-Level Simulator for the Downlink of LTE-A: Case of Study—Cell-Offloading in HetNets

In this paper, we present a novel and efficient data-flow oriented simulation platform for the downlink of Long Term Evolution Advanced (LTE-A). This tool accounts for a wide set of configuration parameters from LTE-A physical and medium access control layers as well as different traffic sources. The simulator, which is implemented in C++, does not consider any link abstraction mechanism, leading to accurate and realistic results. As a case of study, we investigate the performance of cell-offloading for different deployments of small cell base stations that differ in the distance towards their nearest macro base station under File Transfer Protocol type traffic. Additionally, the impact of the spatial user distribution on the performance of cell-offloading is assessed. Results reveal that aggregated throughput is maximized when macro base stations are highly offloaded, which means that a high bias for cell association is advisable in terms of aggregated throughput. However, if the fairness among users is also taken into account, the selected bias for cell-offloading should be smaller.