Multicast Mode Selection for Multi-antenna Coded Caching
A wireless coded caching (CC) setup is considered, where a multi-antenna transmitter delivers contents to multiple cache-enabled users. Exploiting multicasting opportunities provided by the coded caching paradigm, novel interference management schemes are proposed by assigning carefully designed beamforming vectors to different multicast messages. Thereby, the proposed design benefits from spatial multiplexing gain, improved interference management and the global CC gain, simultaneously. In addition, a novel multicast mode selection scheme is proposed which determines the optimum multicast group sizes providing the best complexity-performance tradeoff for a given SNR range. While the proposed scheme exhibits the same near-optimal degrees-of-freedom (DoF) performance as previously proposed methods, it will surpass them at the practical finite SNR regimes. In addition to reducing the complexity, the proposed mode selection feature also provides significantly better rate than previously proposed schemes.