Exploring Coordinated Multipoint Beamforming Strategies for 5G Cellular

Cellular networks are a central part of today's communication infrastructure. The global roll-out of 4G long-term evolution is underway, ideally enabling ubiquitous broadband Internet access. Mobile network operators, however, are currently facing an exponentially increasing demand for network capacity, necessitating densification of cellular base stations (keywords: small cells and heterogeneous networks) and causing a strongly deteriorated interference environment. Coordination among transmitters and receivers to mitigate and/or exploit interference is hence seen as a main path toward 5G mobile networks. We provide an overview of existing coordinated beamforming strategies for interference mitigation in broadcast and interference channels. To gain insight into their ergodic behavior in terms of signal to interference and noise ratio as well as achievable transmission rate, we focus on a simplified but representative scenario with two transmitters that serve two users. This analysis provides guidelines for selecting the best performing method depending on the particular transmission situation.