Latency-Aware Offloading in Integrated Satellite Terrestrial Networks

Wiem Abderrahim,Basem Shihada,Osama Amin,Mohamed-Slim Alouini

doi:10.1109/ojcoms.2020.2988787

Abstract

Next-generation communication networks are expected to integrate newly-used technologies in a smart way to ensure continuous connectivity in rural areas and to alleviate the traffic load in dense regions. The prospective access network in 6G should hinge on satellite systems to take advantage of their wide coverage and high capacity. However, adopting satellites in 6G could be hindered because of the {additional latency introduced}, which is not tolerable by all traffic types. Therefore, we propose a traffic offloading scheme that integrates both the satellite and terrestrial networks to smartly allocate the traffic between them while satisfying different traffic requirements. Specifically, the proposed scheme offloads the Ultra-Reliable Low Latency Communication (URLLC) traffic to the terrestrial backhaul to satisfy its stringent latency requirement. However, it offloads the enhanced Mobile Broadband (eMBB) traffic to the satellite since eMBB needs high data rates but is not always sensitive to delay. Our scheme is shown to reduce the transmission delay of URLLC packets, decrease the number of dropped eMBB packets, and hence improve the network's availability. Our findings highlight that the inter-working between satellite and terrestrial networks is crucial to mitigate the expected high load on the limited terrestrial capacity.

Highlights

W ITH the approaching advent of the 5th generation of mobile cellular networks (5G), the generation of mobile cellular networks (6G) is already required to afford more sophisticated features in terms of coverage and capacity [1]. 6G should ensure global connectivity by connecting under-served areas where access to the Internet is limited or absent, but it should mitigate the limitations in the capacity of terrestrial links, especially with the increasing data demand in dense networks
To overcome the previously discussed shortcomings, we propose to manage the multiplexing of the enhanced Mobile Broadband (eMBB) traffic and the Ultra-Reliable Low Latency Communication (URLLC) traffic in integrated satellite terrestrial networks (ISTN)
In the rest of the paper, we focus on a single satellite of the network and we denote the data rate between the fixed satellite and the small base station bsi by Rj, and the offloaded amount of eMBB traffic between from the satellite and the i − th small base station, i.e., bsi by βi

Summary

Introduction

W ITH the approaching advent of the 5th generation of mobile cellular networks (5G), the generation of mobile cellular networks (6G) is already required to afford more sophisticated features in terms of coverage and capacity [1]. 6G should ensure global connectivity by connecting under-served areas where access to the Internet is limited or absent, but it should mitigate the limitations in the capacity of terrestrial links, especially with the increasing data demand in dense networks. Of the mix of access technologies in 6G, satellite communications will play a pivotal role due to their wide coverage. Different mega-constellations of LEOs are being manufactured and partially launched into space lately. The aerospace manufacturer SpaceX has an ambitious project to cover the Earth with around 12000 LEO satellites [2]. SpaceX is racing against Amazon and OneWeb, which plan to launch 3236 satellites (Project Kuiper) and 650 satellites, respectively [2], [4]. They all aim to widen the terrestrial network’s connectivity and, more crucially to extend its limited capacity [5]

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