Modeling and Analysis of Two-Way Relay Non-Orthogonal Multiple Access Systems

Abstract

A two-way relay non-orthogonal multiple access (TWR-NOMA) system is investigated, where two groups of NOMA users exchange messages with the aid of one half-duplex (HD) decode-and-forward (DF) relay. Since the signal-plus-interference-to-noise ratios (SINRs) of NOMA signals mainly depend on effective successive interference cancellation (SIC) schemes, imperfect SIC (ipSIC) and perfect SIC (pSIC) are taken into account. In order to characterize the performance of TWR-NOMA systems, we first derive closed-form expressions for both exact and asymptotic outage probabilities of NOMA users' signals with ipSIC/pSIC. Based on the derived results, the diversity order and throughput of the system are examined. Then we study the ergodic rates of users' signals by providing the asymptotic analysis in high SNR regimes. Lastly, numerical simulations are provided to verify the analytical results and show that: 1) TWR-NOMA is superior to TWR-OMA in terms of outage probability in low SNR regimes; 2) Due to the impact of interference signal (IS) at the relay, error floors and throughput ceilings exist in outage probabilities and ergodic rates for TWR-NOMA, respectively; and 3) In delay-limited transmission mode, TWR-NOMA with ipSIC and pSIC have almost the same energy efficiency. However, in delay-tolerant transmission mode, TWR-NOMA with pSIC is capable of achieving larger energy efficiency compared to TWR-NOMA with ipSIC.

arXiv comment12 pages, 8 figures. arXiv admin note: substantial text overlap with arXiv:1801.08177

References in corpus (7)

• Relaying Protocols for Wireless Energy Harvesting and Information Processing
• On the Performance of Non-Orthogonal Multiple Access in 5G Systems with Randomly Deployed Users
• Cooperative Non-Orthogonal Multiple Access with Simultaneous Wireless Information and Power Transfer
• Non-orthogonal Multiple Access in Large-Scale Underlay Cognitive Radio Networks
• Exploiting Full/Half-Duplex User Relaying in NOMA Systems
• Relay Selection for Cooperative NOMA
• Modulation and Multiple Access for 5G Networks

Cited by in corpus (6)

• Evolution of NOMA Toward Next Generation Multiple Access (NGMA) for 6G
• Capacity and outage analysis of a dual-hop decode-and-forward relay-aided NOMA scheme
• Heterogeneous Power-Splitting Based Two-Way DF Relaying with Non-Linear Energy Harvesting
• Interplay Between NOMA and Other Emerging Technologies: A Survey
• Exploiting NOMA for UAV Communications in Large-Scale Cellular Networks
• Improved User Fairness in Decode-Forward Relaying Non-orthogonal Multiple Access Schemes with Imperfect SIC