  Coded caching (CC) can substantially enhance network performance by
leveraging memory as an additional communication resource. However, the use of
CC is challenging in various practical applications due to dynamic user
behavior. The existing solutions, based on shared caching, cannot directly
handle all scenarios where users freely enter and depart the network at any
time as they are constrained by specific conditions on network parameters. This
paper proposes a universally applicable shared-caching scheme for dynamic
setups without any restriction on network parameters. The closed-form
expressions for the achievable degrees of freedom (DoF) are computed for the
resulting generalized scheme, and are shown to achieve the existing optimal
bounds of the shared-cache model. Furthermore, a
successive-interference-cancellation-free extension based on a fast iterative
optimized beamformer design is devised to optimize the use of excess spatial
dimensions freed by cache-aided interference cancellation. Extensive numerical
experiments are carried out to assess the performance of the proposed scheme.
In particular, the results demonstrate that while a dynamic setup may achieve a
DoF substantially lower than the optimal DoF of shared caching, our proposed
scheme significantly improves the performance at the finite signal-to-noise
ratio compared to unicasting, which only benefits from the local caching gain.
