Two-Tier Cache-Aided Full-Duplex Hybrid Satellite–Terrestrial Communication Networks

Abstract

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.

Physical Layer Security in IRS-Assisted Cache-Enabled Hybrid Satellite-Terrestrial Networks

“…At R s,1 = R s,2 = 1bits/s/Hz, the optimal P * is at 80% with R * e,1 = 5.5 bits/s/Hz and R * e,2 = 11 bits/s/Hz, while the non-optimized P (in Fig. 6) only achieves its highest value at 72% with R e,1 = R e,2 = 11.25bits/s/Hz.To further compare the optimal probabilistic caching policy, the system probability of secure transmission under ground station and satellite most popular caching policies [7] are also provided in Fig. 11.…”

A Survey on Cache-Aided NOMA for 6G Networks

“…Armon et al have designed and addressed operating issues of cache-aided satellite distribution systems for web caching [159], [160]. To minimize the downlink and uplink traffic load, Wu et al have proposed a two-layer caching model for satellite-terrestrial networks, where caching in the ground stations constitutes the first layer and caching in the satellite constitutes the second layer [161], [162]. The authors have validated that two content caching schemes, named as most popular content-based and uniform contentbased schemes can efficiently improve the spectral efficiency in the Hybrid satellite-terrestrial relay networks [163].…”

Physical Layer Security in IRS-Assisted Cache-Enabled Satellite Communications Networks

“…Under review for possible publication network (STN) has been proved to effectively offload the backhaul of terrestrial networks [2], reduce the content delivery time [3], [4], enhance the outage probability [5], and the successful delivery probability [6], etc. Nonetheless, satcom is more exposed to security vulnerabilities due to the openness of transmission medium as well as the large beam coverage area of satellites.…”

“…Motivated by the above discussions, this paper investigates PLS for IRS-assisted two-tier cache-enabled STN, in which content caches are deployed at both satellite and ground station. The two-tier cache-enabled STN has been proposed to enhance satellite bandwidth consumption [3] and service delivery time [6]. Since probabilistic caching can effectively improve the cache hit ratio [22], it is employed at both cache tiers in this work.…”