Performance Evaluation of Beamforming for Macro Base Stations in a Femto-Cell Assisted Macro-Network

In this paper we present the impact of femtocell underlay deployment sharing same radio frequency resources with urban macro-cell in terms of throughput performance of enodeBs in the presence of inter cell interference that a femto base station environment adds to users served by enodeBs and vice versa. The performance of the two systems, one with femto base station indoor deployment for indoor users only is compared to a system where all indoor and outdoor users are served with the macro base stations in an open access manner. To evaluate this, we have designed and implemented an open access simulation test bed that estimates the throughput in every point of an integrated femtocell assisted macrocell network. It is demonstrated that significant overall network throughput gains can be achieved through such femtocell deployment partly lowering macroBS efficiency which is improved by applying beamforming coordination on macroBS and femtoBS. The detailed illustration and dynamic downlink system level simulations are carried out to validate this coordination. Results clearly indicate that the benefits of beamforming for femtocells deployment by far outweigh their impact on the macrocell capacity delivering higher throughputs from macro base stations for outdoor users.