Enabling NOMA in Overlay Spectrum Sharing in Hybrid Satellite-Terrestrial Systems

Abstract

In this paper, a hybrid satellite-terrestrial spectrum sharing system allows terrestrial secondary network to cooperate with a primary satellite network and to further provide higher spectrum efficiency. For massive connections design, we implement non-orthogonal multiple access (NOMA) technique to form cognitive radio based satellite-terrestrial (CR-NSHT) system relying on NOMA and further achieve more benefits compared with traditional schemes. The secondary network only remains its stable operation when the outage probability of such system is guaranteed, and thereby, to explore advantages of spectrum sharing opportunities. Considering Shadowed-Rician fading for satellite links, and Nakagami-m as well as Rician fading for terrestrial links, we derive the closed-form expressions of the outage probability to evaluate performance of secondary network. We find that several impacts on performance metrics such as power allocation factors, transmit signal to noise ratio (SNR) at the source, parameters of satellite links, target rates and values of fading channels. We consider further system performance metrics including ergodic capcity, energy efficiency and multi-user scenarios. Numerical and simulation results validate our analysis and highlight the performance gains of the proposed schemes for CR-NSHT with relay link serving secondary network and direct link serving the primary network.INDEX TERMS Hybrid satellite-terrestrial systems, cognitive radio, spectrum sharing, outage probability.

Performance evaluation of nonlinear energy scavenging overlay networks

“…With the aid of the SIC, SD recovers first t p by considering t s as noise and then removes the primary interference ‡ induced by t p prior to recovering its secondary information t s . Accordingly, (6) generates signalto-interference plus noise ratio (SINR) for SD to restore t p as…”

“…Until now, some publications have studied on the overlay paradigm while both the interweave and underlay paradigms have been found broadly in the literature. The overlay paradigm can be implemented by asking an SU to aid a PU by superimposing secondary signal with primary signal before transmission where the power allotted to the primary signal is superior to that allocated to the secondary signal—a mechanism same as non‐orthogonal multiple access (NOMA) 6–12 . NOMA is a feasible‐and‐efficient paradigm to meliorate spectrum utilization and was recommended within and beyond 5G.…”

“…The overlay paradigm can be implemented by asking an SU to aid a PU by superimposing secondary signal with primary signal before transmission where the power allotted to the primary signal is superior to that allocated to the secondary signal-a mechanism same as nonorthogonal multiple access (NOMA). [6][7][8][9][10][11][12] NOMA is a feasible-and-efficient paradigm to meliorate spectrum utilization and was recommended within and beyond 5G. Remarkably, allocating distinct power levels to the primary and secondary messages in the overlay paradigm facilitates sequential decoding in combination with interference cancelation, namely, successive interference cancelation (SIC), eventually enhancing the system performance.…”

Rate-Energy Tradeoff Analysis in RIS-SWIPT Systems With Hardware Impairments and Phase-Based Amplitude Response

“…To this end, the potential key enabling technologies and solutions of future 6G networks include massive MIMO [10], dynamic spectrum sharing with full-duplex (FD)/device-todevice (D2D) communications [11], artificial intelligence (AI) [12], terahertz (THz) bands [13], non-terrestrial communications [14], reconfigurable intelligent surface (RIS) [15], and simultaneous wireless information and power transfer (SWIPT) [16]. In particular, RIS and SWIPT are the novel technologies to enable the energy efficiency and spectrum efficiency and provide the innovative solutions to the inherent challenges in the developments of the 6G systems.…”

Performance of Spectrum Sharing in Hybrid Satellite Terrestrial Network with Opportunistic Relay Selection

“…When satellite terminals are located inside buildings or in dense forests, they are susceptible to masking effects that cause line-of-sight (LOS) communications between satellites and terrestrial users to be disrupted. To address the issue of LOS communication disruptions, hybrid satellite-terrestrial relay systems that assist satellite transmissions by deploying terrestrial relays have attracted considerable research interest in both academia and industry [6]. Recently, terrestrial relay options for relaying signals have attracted considerable interest in hybrid satelliteterrestrial networks, which can increase the channel capacity of satellite links.…”