Wireless Coded Caching Can Overcome the Worst-User Bottleneck by Exploiting Finite File Sizes

We address the worst-user bottleneck of wireless coded caching, which is known to severely diminish cache-aided multicasting gains due fundamental worst-channel limitation multicasting. consider quasi-static Rayleigh fading Broadcast Channel, for we first show that effective caching gain standard XOR-based coded-caching scheme completely vanishes in low signal-to-noise ratio (SNR) regime. Then, reveal this collapse not intrinsic caching. do so by presenting a novel can fully recover capitalizing on one aspect has remained unexploited date: shared side information brought about effectively unavoidable file-size constraint. As consequence, effect dramatically ameliorated, as it substituted much more subtle worst-group-of-users effect, where suggested grouping fixed, and decided before channel or demands are known. Furthermore, theoretical recovered number users increases, done without any user selection technique. analyze rate performance proposed derive approximations prove be very precise. Importantly, approach translated other schemes scenarios, including decentralized scenarios.