A coordinated non-orthogonal multiple access strategy for integrated terrestrial-satellite networks

Area of Science:

• Wireless Communication Networks
• Satellite Communications
• Information Theory

Background:

• Integrated Satellite-Terrestrial Networks (ISTN) are emerging to provide ubiquitous connectivity.
• Cooperative Non-Orthogonal Multiple Access (CNOMA) offers potential spectral efficiency gains.
• Limited research exists on CNOMA performance in ISTN with multi-antenna users and imperfect channel information.

Purpose of the Study:

• To analyze the outage probability and ergodic sum capacity of downlink ISTN employing a CNOMA scheme.
• To evaluate the impact of imperfect channel state information on system performance.
• To compare the performance of CNOMA against Orthogonal Multiple Access (OMA) schemes.

Main Methods:

• Derivation of exact analytical expressions for outage probability and ergodic sum capacity.
• Modeling of ISTN with multi-antenna users under a single satellite beam.
• Inclusion of a cooperative relaying mechanism where a user with better channel conditions assists others.
• Consideration of a pilot-based channel estimation method to account for imperfect channel state information.

Main Results:

• The CNOMA scheme significantly outperforms OMA (specifically TDMA) in the analyzed ISTN model.
• Analytical expressions for outage probability and ergodic sum capacity were successfully derived.
• The cooperative relaying aspect within CNOMA enhances overall system performance.

Conclusions:

• The proposed CNOMA scheme is a viable and high-performing solution for future ISTN.
• Imperfect channel estimation does not preclude the benefits of CNOMA.
• Further research can explore advanced techniques to further boost ISTN capacity.