Cache-enabled heterogeneous wireless networks with random discontinuous transmission

In this paper, to make better use of file diversity provided by random caching and improve the successful transmission probability (STP) of a file, we consider retransmissions with random discontinuous transmission (DTX) in a large-scale cache-enabled heterogeneous wireless network (HetNet) employing random caching. We analyze the STP in two mobility scenarios, i.e., the high mobility scenario and the static scenario. In each scenario, by using tools from stochastic geometry and series expansion of some special functions, we obtain the closed-form expressions for the STP in the general and low signal-to-interference ratio (SIR) threshold regimes, respectively. It shows that a larger caching probability corresponds to a higher STP in both scenarios; random DTX can improve the STP in the static scenario and its benefit gradually diminishes when mobility increases. In addition, the asymptotic analysis shows that the diversity gain is jointly affected by random caching and random DTX in both scenarios.