Efficient Multicast Beamforming in HetNet with an Opportunistic Cells Activation

This paper focuses on coordinated multicell multicast transmissions in Heterogeneous Networks (HetNets). In particular the HetNet Multicast Problem (HMP) is formulated, whose goal is to to improve the quality of the multicast service by maximizing signal to noise ratio (SNR) of the user with the worst channel conditions, but taking into account the energy consumption issue. Indeed, the small cells are activated opportunistically, only when needed, using suitable beamfoming weights. In addition the maximum number of activated small cells can be limited. Then, due to the complexity of the problem a suboptimal iterative solution is proposed and its performance in terms of minimum SNR and energy consumption is validated by means a comparison with other benchmark solutions.