Balancing egoistic and altruistic transmit beamforming in femtocell networks

In this paper, we study the balancing of egoistic (maximum-ratio, MR) and altruistic (zero-forcing, ZF) beamforming (BF) in femtocells through simulations. To investigate the achievable gains from operating between the extremes (egoism/altruism) we analyze the performance of beamformers constructed as linear combinations of the MR and ZF beamformers in case of equal gain transmission. We find that significant gains can be achieved if each femto access point (FAP) has knowledge of the preferred MR and ZF beamforming vectors and can choose its strategy accordingly. We also show that the optimality of any such strategy is strongly influenced by the applied criteria (sum rate maximization, fairness etc.).