Vector Coded Caching Substantially Boosts MU-MIMO: Pathloss, CSI and Power-allocation Considerations

We here continue the exploration of vector coded caching and its powerful effect on the performance of multiuser multiple-input multiple-output (MU-MIMO) systems. In particular, this paper investigates the impact that vector coded caching under various practical considerations, which include channel state information acquisition costs, multi-antenna receivers, variable pathloss, as well as max-min fairness where the minimum transmission rate among the simultaneously served users is maximized via power allocation. We here focus on the widely adopted zero-forcing precoder, and proceed to show the large multiplicative boost brought about by vector coded caching over the optimized cacheless counterpart. To do so, we here provide lower and upper bounds on the overall throughput as well as on the effective gain (i.e., on the rate improvement over the optimized cacheless counterpart), again in the presence of the aforementioned practical aspects. Finally various numerical results demonstrate the tightness of the derived upper and lower bounds, as well as nicely illustrate the notable gains.