16 research outputs found
Hybrid satellite-terrestrial relay network: proposed model and application of power splitting multiple access
The development of hybrid satellite-terrestrial relay networks (HSTRNs) is one of the driving
forces for revolutionizing satellite communications in the modern era. Although there are many unique
features of conventional satellite networks, their evolution pace is much slower than the terrestrial
wireless networks. As a result, it is becoming more important to use HSTRNs for the seamless integration
of terrestrial cellular and satellite communications. With this intent, this paper provides a comprehensive
performance evaluation of HSTRNs employing non-orthogonal multiple access technique. The terrestrial
relay is considered to be wireless-powered and harvests energy from the radio signal of the satellite.
For the sake of comparison, both amplify-and-forward (AF) and decode-and-forward (DF) relaying
protocols are considered. Subsequently, the closed-form expressions of outage probabilities and ergodic
capacities are derived for each relaying protocol. Extensive simulations are performed to verify the
accuracy of the obtained closed-form expressions. The results provided in this work characterize the
outage and capacity performance of such a HSTRN.publishe
Hybrid satellite–terrestrial networks toward 6G : key technologies and open issues
Future wireless networks will be required to provide more wireless services at higher data rates and with global coverage. However, existing homogeneous wireless networks, such as cellular and satellite networks, may not be able to meet such requirements individually, especially in remote terrain, including seas and mountains. One possible solution is to use diversified wireless networks that can exploit the inter-connectivity between satellites, aerial base stations (BSs), and terrestrial BSs over inter-connected space, ground, and aerial networks. Hence, enabling wireless communication in one integrated network has attracted both the industry and the research fraternities. In this work, we provide a comprehensive survey of the most recent work on hybrid satellite–terrestrial networks (HSTNs), focusing on system architecture, performance analysis, design optimization, and secure communication schemes for different cooperative and cognitive HSTN network architectures. Different key technologies are compared. Based on this comparison, several open issues for future research are discussed
5G embraces satellites for 6G ubiquitous IoT : basic models for integrated satellite terrestrial networks
Terrestrial communication networks mainly focus on users in urban areas but have poor coverage performance in harsh environments, such as mountains, deserts, and oceans. Satellites can be exploited to extend the coverage of terrestrial fifth-generation (5G) networks. However, satellites are restricted by their high latency and relatively low data rate. Consequently, the integration of terrestrial and satellite components has been widely studied, to take advantage of both sides and enable the seamless broadband coverage. Due to the significant differences between satellite communications (SatComs) and terrestrial communications (TerComs) in terms of channel fading, transmission delay, mobility, and coverage performance, the establishment of an efficient hybrid satellite-terrestrial network (HSTN) still faces many challenges. In general, it is difficult to decompose a HSTN into a sum of separate satellite and terrestrial links due to the complicated coupling relationships therein. To uncover the complete picture of HSTNs, we regard the HSTN as a combination of basic cooperative models that contain the main traits of satellite-terrestrial integration but are much simpler and thus more tractable than the large-scale heterogeneous HSTNs. In particular, we present three basic cooperative models, i.e., model X, model L, and model V, and provide a survey of the state-of-the-art technologies for each of them. We discuss future research directions towards establishing a cell-free, hierarchical, decoupled HSTN. We also outline open issues to envision an agile, smart, and secure HSTN for the sixth-generation (6G) ubiquitous Internet of Things (IoT)
Auction-based Multi-Channel Cooperative Spectrum Sharing in Hybrid Satellite-Terrestrial IoT Networks
In this paper, we investigate the multi-channel cooperative
spectrum sharing in hybrid satellite-terrestrial internet
of things (IoT) networks with the auction mechanism, which is
designed to reduce the operational expenditure of the satellitebased
IoT (S-IoT) network while alleviating the spectrum scarcity
issues of terrestrial-based IoT (T-IoT) network. The cluster
heads of selected T-IoT networks assist the primary satellite
users transmission through cooperative relaying techniques in
exchange for spectrum access. We propose an auction-based
optimization problem to maximize the sum transmission rate
of all primary S-IoT receivers with the appropriate secondary
network selection and corresponding radio resource allocation
profile by the distributed implementation while meeting the
minimum transmission rate of secondary receivers of each TIoT
network. Specifically, the one-shot Vickrey-Clarke-Groves
(VCG) auction is introduced to obtain the maximum social
welfare, where the winner determination problem is transformed
into an assignment problem and solved by the Hungarian algorithm.
To further reduce the primary satellite network decision
complexity, the sequential Vickrey auction is implemented by
sequential fashion until all channels are auctioned. Due to
incentive compatibility with those two auction mechanisms, the
secondary T-IoT cluster yields the true bids of each channel,
where both the non-orthogonal multiple access (NOMA) and time
division multiple access (TDMA) schemes are implemented in
cooperative communication. Finally, simulation results validate
the effectiveness and fairness of the proposed auction-based
approach as well as the superiority of the NOMA scheme in
secondary relays selection. Moreover, the influence of key factors
on the performance of the proposed scheme is analyzed in detail