Caching in mobile HetNets: A throughput-delay trade-off perspective

Abstract

We analyze the optimal throughput-delay trade-off in content-centric mobile heterogeneous networks (HetNets), where each node moves according to the random walk mobility model and requests a content object from the library independently at random, according to a Zipf popularity distribution. Instead of allowing access to all content objects at base stations (BSs) via costly backhaul, we consider a more practical scenario where mobile nodes and BSs, each having a finite-size cache space, are able to cache a subset of content objects so that each request is served by other mobile nodes or BSs via multihop transmissions. Under the protocol model, we characterize a fundamental throughput-delay trade-off in terms of scaling laws by introducing our content delivery routing protocol and the corresponding optimal caching allocation strategy.