Pairwise error probability evaluation of cooperative mobile femtocells

Abstract

Cellular subscribers while travelling in public transportation vehicles, such as streetcars and buses, often experience poor signal reception and low bandwidth when using their cellular devises onboard. Small cell deployment of, for example, femtocells is considered as one of the most promising solutions for cellular operators to enhance coverage and meet the increasing need for capacity and QoS support expected by cellular subscribers. We consider a mobile Femto Base Station (mobFBS) installed in the public transportation vehicle, with an external antenna installed on the roof, to offer enhanced coverage and improved capacity onboard. We investigate the performance gains of a communication scheme in downlink LTE-A networks with mobFBSs. Users are assumed to be travelling using a public transportation vehicle, and the transmission between macroBS and users occurs through a mobFBS. The associated wireless links for this type of fast mobility are characterized by a doubly-selective fading channel. This causes performance degradation in terms of increased error probability. By taking advantage of the more powerful central processing mobFBS, we make use of a precoded technique to overcome the performance degradation that results from the wireless fading channel. We investigate the performance gain in terms of pairwise error probability (PEP) via a derived closed-form expression. Our analytical and simulation results indicate that significant diversity gains are achievable and error rates are tremendously reduced.