Cache-Aware Multicast Beamforming Design for Multicell Multigroup Multicast

To promote the massive video content delivery and to realize the long-term overall cost, the caching and computing functions have to be installed at some intermediate nodes within the networks. This paper presents a cache-aware multicast beamforming design for multicell multigroup multicast, where information-centric networking and mobile edge computing techniques are brought in the multicell multicast system to cache and transcode the contents passing through the nodes. The proposed cache-aware multicast beamforming design jointly optimizes the multicast mode, the caching strategy, and the network-wide beamforming vector, and focuses on minimizing the energy cost of the caching, computing, and communications. To make the formulated problem tractable, a two step method is proposed in this paper, where the first step is devoted to the cache-aware multicast approach design, while the second step is focused on the sparse multicast beamforming design. Furthermore, in order to promote the stabilization of the system, we further design a robust joint optimization strategy for the scenario with the imperfect channel state information. Extensive simulations are conducted to evaluate the performance of our proposed schemes.