Network capacity enhancement of OFDMA system using self-organized femtocell off-load

As plug-and-play devices, femtocells are expected to be self-managed, empowered by self-organization functionalities. This paper presents a Self-organizing networks (SON) process for off-loading macrocell traffic towards Open Subscriber Group (OSG) femtocells. The off-loading process comprises two SON functionalities: the first configures the femtocell transmitted pilot power, which depends on the received macrocell pilot power and the density of femtocells. The femtocell pilot powers are chosen using a look-up table generated through an off-line queuing theory based analysis. To mitigate interference from femtocells with different transmission powers, a self-optimizing Inter-Cell Interference Coordination (ICIC) functionality is activated. The performance gain of the self-organizing mechanisms is evaluated using a large scale network simulator. It is shown that in dense femtocell deployment, the SON off-loading can bring about considerable capacity gain.