Vector Coded Caching Greatly Enhances Massive MIMO

Abstract

The use of vector coded caching has been shown to provide important gains and, more importantly, to alleviate the impact of the file-size constraint, which prevents coded caching from obtaining its ideal gains in practical settings. In this work, we analyze the performance of vector coded caching in the massive MIMO regime, aiming at understanding the benefits that allowing users to cache a practical amount of data could bring to realistic settings in such massive MIMO regime. In particular, we separately consider two linear precoding schemes and analyze the corresponding throughput, for which we derive simple but precise upper and lower bounds. These bounds enable us to characterize the delivery speed-up gain over the uncoded caching setting when the CSI acquisition costs are taken into account. Numerical results demonstrate the tightness of the derived bounds and show a significant boost over uncoded caching and the standard cacheless setting.