Energy efficient and interference management with MISO beamforming in femtocells

Energy efficient beamforming problem is considered for a multiple input single output (MISO) femtocell network, which consists of multi antenna femtocell base stations (FBSs) and single antenna femtocell users (FUs). The transmit beamforming vectors are designed to maximize the energy efficiency (EE) in the downlink transmission of the femtocell network. The objective function is defined as “data rate/power consumption” which has the unit bits/Hz/Joule to measure the energy efficiency of the network. First, an optimization model based on maximizing the EE of each femtocell with maximum transmit power and interference constraints is formulated and it is not a convex problem. Second, the fraction algorithm is utilized to transform the non-convex problem into convex problem, which can be solved by its dual problem. Finally, the simulation result shows that our proposed scheme improve the EE of femtocells compared with others. And the behavior of the objective function is observed in different antenna configurations by varying the number of femtocells.