Temporal-Spatial Request Aggregation for Cache-Enabled Wireless Multicasting Networks

Existing multicasting schemes for massive content delivery do not fully utilize multicasting opportunities in elastic content-oriented services. In this paper, we propose a novel temporal-spatial request aggregation-based multicasting scheme in a large-scale cache-enabled wireless network, which can effectively exploit multicasting opportunities in asynchronous file requests for elastic services to improve spectral efficiency. Utilizing tools from stochastic geometry, we derive tractable expressions for the successful transmission probability. The analytical results show that the successful transmission probability increases and the energy consumption decreases, at the cost of delay increase, in the large and small user density regions. Based on the analytical results, we further optimize the successful transmission probability with respect to the caching probability and BS on/off period. We obtain closed-form solutions in the two asymptotic regions. Finally, we characterize the temporal and spatial request aggregation gains in the two asymptotic regions, and reveal the impacts of the popularity profile on them.