Power Efficient MISO Caching With Practical Subpacketization via User Scheduling

We present a novel power-efficient and low-complexity scheme for cache-aided communication in networks with a multi-antenna base station that serves multiple single-antenna users. The scheme is based on transmitting coded messages to disjoint groups of users simultaneously and achieves an important trade-off between performance and complexity. The subpacketization level of the proposed scheme is sub-optimum compared to the state-of-the-art but is still feasible for a practical range of network parameters. On the other hand, the scheme achieves near-optimal performance and asymptotically achieves the same degrees of freedom (DoF) as the best-known schemes achieve. However, compared to other optimum achievable rates, the proposed scheme suffers from minor performance degradation due to power loss, which becomes negligible as the signal-to-noise ratio or the number of users grows. In return, the reductions in complexity and subpacketization allow for practical implementation of this scheme even for a large number of users. The presented scheme is also very flexible to the variation of the network topology and can easily be generalized to heterogeneous and dynamic scenarios.