Two-Tier Cache-Aided Full-Duplex Hybrid Satellite-Terrestrial Communication Systems
preprintposted on 20.08.2021, 13:03 authored by Quynh NgoQuynh Ngo, Tran Khoa PhanTran Khoa Phan, Wei XiangWei Xiang, Abdun MahmoodAbdun Mahmood, Jill SlayJill Slay
Enabling global Internet access is challenging for cellular-based Internet of Things (IoT) due to the limited range of terrestrial network services. One viable solution is to deploy IoT over satellite systems for coverage extension. However, operating a hybrid satellite-terrestrial network (STN) might incur high satellite bandwidth consumption and excessive service latency. Aiming to reduce the content delivery latency from the Internet-connected gateway to the users, this work proposes a wireless two-tier cache-enabled model with full-duplex transmissions where content caches are deployed at the satellite and ground station. A closed-form solution for the successful delivery probability (SDP) of the files is derived considering the requested content distributions and channel statistics. Then, the SDP performance under common caching policies can be conveniently evaluated. The results are also used to optimize cache placement under caching capacity constraints. Numerical results demonstrate the performance improvements of the proposed system over those of single-tier cache-aided and half-duplex transmission systems.