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

In this paper, we investigate the outage probability and ergodic sum capacity of the downlink of the integrated satellite-terrestrial networks (ISTN) with a cooperative non-orthogonal multiple access (CNOMA) scheme, in which a user with better channel condition acts as a relay node and forwards information to the other users. In this paper, a pilot-based channel estimation method is considered which can verify the performance of this scheme with the imperfect channel state information. In this model, all these users are equipped with multi-antennas, and all of them are both in the coverage of a same beam of the satellite. Specifically, the exact analytical expression for the outage probability and ergodic sum capacity of the system is derived. The result shows that this coordinated non-orthogonal multiple access (CNOMA) scheme performs better than that of OMA (TDMA) in this model. Finally, the future research directions are given to further enhance the system capacity.

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On Secrecy Outage Probability for Downlink NOMA Systems With Relay-Antenna Selection

10.21203/rs.3.rs-1119431/v1 ◽

2021 ◽

Author(s):

Shu Xu ◽

Chen Liu ◽

Hong Wang ◽

Mujun Qian ◽

Wenfeng Sun

Keyword(s):

Outage Probability ◽

Multiple Access ◽

Antenna Selection ◽

Maximal Ratio Combining ◽

Selection Combining ◽

Secrecy Outage Probability ◽

Channel State ◽

Secrecy Outage ◽

Secure Transmission ◽

Theoretical Results

Abstract Secure transmission is essential for future non-orthogonal multiple access (NOMA) system. This paper investigates relay-antenna selection (RAS) to enhance physical-layer security (PLS) of cooperative NOMA system in the presence of an eavesdropper, where multiple antennas are deployed at the relays, the users, and the eavesdropper. In order to reduce expense on radio frequency (RF) chains, selection combining (SC) is employed at both the relays and the users, whilst the eavesdropper employs either maximal-ratio combining (MRC) or selection combining (SC) to process the received signals. Under the condition that the channel state information (CSI) of the eavesdropping channel is available or unavailable, two e↵ective relay-antenna selection schemes are proposed. Additionally, the closed-form expressions of secrecy outage probability (SOP) are derived for the proposed relay-antenna selection schemes. In order to gain more deep insights on the derived results, the asymptotic performance of the derived SOP is analyzed. In simulations, it is demonstrated that the theoretical results match well with the simulation results and the SOP of the proposed schemes is less than that of the conventional orthogonal multiple access (OMA) scheme obviously.

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Exploiting non-orthogonal multiple access in device-to-device communication

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v22.i2.pp919-926 ◽

2021 ◽

Vol 22 (2) ◽

pp. 919

Author(s):

Sang Hoon Lee ◽

Soo Young Shin

Keyword(s):

Closed Form ◽

Interference Cancellation ◽

Multiple Access ◽

D2d Communication ◽

System Capacity ◽

Time Sharing ◽

Sum Capacity ◽

Closed Form Solutions ◽

Device To Device ◽

Device To Device Communication

This paper proposes an uplink non-orthogonal multiple access (NOMA) system with device-to-device (D2D) communication, enabling NOMA users to communicate with other users/devices using D2D communication to improve the system capacity. In the NOMA-D2D system, two cellular users communicated with the BS using uplink NOMA, and two cellular users simultaneously communicated with the D2D users using downlink NOMA. Closed-form solutions for the ergodic sum capacity of the proposed system are derived analytically. The analytical results are validated via simulations and they are compared with the results obtained from conventional schemes. The comparison shows that, in scenarios where efficient interference cancellation can be achieved, the proposed NOMA system with the D2D model can achieve higher capacity gains than conventional benchmark schemes. When dB, NOMA-D2D achieves capacity gains of 192.2% and 157.5% over the conventional OMA and the time-sharing-based NOMA, respectively.

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A Survey on Future Generation Wireless Communications-6G: Requirements, Technologies, Challenges and Applications

International Journal of Advanced Trends in Computer Science and Engineering ◽

10.30534/ijatcse/2021/211052021 ◽

2021 ◽

Vol 10 (5) ◽

pp. 3067-3076

Keyword(s):

Future Generation ◽

System Capacity ◽

Future Research ◽

Wireless System ◽

Research Directions ◽

Sixth Generation ◽

Data Rates ◽

Future Research Directions ◽

New Perspective

Within the last few decades, wireless connectivity has experienced an exponential growth. With far more features than 4G communications, next-generation (5G) will soon be available worldwide. In the year 2027 to 2030, the sixth- generation (6G) wireless system, fully supported by artificial intelligence, will become the dominant paradigm for wireless communication. Beyond 5G, the main factors to consider are higher system capacity, greater data rates, reduced latency, enhanced security, and improved quality of service (QoS) compared to current 5G systems. In this paper, we describe the strategy for future 6G wireless networks, emerging technologies and the architecture within which they will operate. This paper focuses on key performance indicators, applications, new services, and key technologies that could enable 6G networks. By presenting a new perspective on future research directions, this article will make a significant contribution to future research directions.

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A Survey on Non-Orthogonal Multiple Access: From the Perspective of Spectral Efficiency and Energy Efficiency

Energies ◽

10.3390/en13164106 ◽

2020 ◽

Vol 13 (16) ◽

pp. 4106 ◽

Cited By ~ 1

Author(s):

Hieu V. Nguyen ◽

Hyeon Min Kim ◽

Gil-Mo Kang ◽

Kha-Hung Nguyen ◽

Van-Phuc Bui ◽

...

Keyword(s):

Energy Efficiency ◽

Spectral Efficiency ◽

Multiple Access ◽

Future Research ◽

Research Directions ◽

Radio Resources ◽

Future Research Directions ◽

Reduce Energy Consumption ◽

Green Wireless Communications

Non-orthogonal multiple access (NOMA) is a promising technology for next-generation wireless networks with emerging demands on low latency, high throughput, and massive connectivity. Unlike orthogonal multiple access, NOMA allows multiple users to share the same radio resources, which significantly improves spectral efficiency (SE). To achieve green wireless communications for numerous networked devices, NOMA helps reduce energy consumption while satisfying rate fairness and quality-of-experience requirements. The goal of this paper is to introduce the innovative approaches for NOMA in terms of the SE and energy efficiency, and discuss emerging technologies involved with NOMA. Further, its challenges and future research directions are highlighted.

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