Beamforming in Single Frequency Networks with Connection Control

We evaluate the benefit of beamforming for broadcast/multicast transmission using single frequency networks (SFNs), where the beamforming weights are jointly optimized for the base stations participating in the SFN transmission. The aim is to reduce the total transmission power under the constraint of the provision of a certain mean SNR to all users. In order to keep the number of base stations to which a user is connected low, we apply a sensitivity analysis to the optimization problem and identify the users that should connect to further base stations to lower the required transmission power most effectively.