scholarly journals On Outage Probability and Ergodic Rate of Downlink Multi-User Relay Systems with Combination of NOMA, SWIPT, and Beamforming

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4737 ◽  
Author(s):  
Ta Chi Hieu ◽  
Nguyen Le Cuong ◽  
Tran Manh Hoang ◽  
Do Thanh Quan ◽  
Pham Thanh Hiep
Keyword(s):  
Energy Harvesting ◽  
Outage Probability ◽  
Fading Channels ◽  
System Performance ◽  
Interference Cancellation ◽  
Base Station ◽  
Optimal Time ◽  
Relay Nodes ◽  
Channel State ◽  
Relay Systems

A downlink of multi-user non-orthogonal multiple access (NOMA) relay systems is considered. To improve system performance, relay nodes are used to forward signals from the base station (BS) to the end users, and they are wirelessly powered by energy harvesting from the radio frequency transmitted from the BS. Moreover, beamforming is applied at the BS based on multiple antennas and relay nodes consist of one transmit antenna but several receive ones. The system performance is demonstrated through closed-form expressions of outage probability (OP) and ergodic rate (ER) over Rayleigh fading channels. The proposed system is investigated in two cases of perfect and imperfect successive interference cancellation (SIC), and the imperfect channel state information condition is also taken into consideration. The OP and ER are calculated in many scenarios and the optimal time fraction of energy harvesting corresponding to the minimum OP is discussed. The exact and approximate theoretical results are compared with the simulation result to confirm the proposed theoretical analysis method.

Effect of CSI Imperfection on Cognitive Underlay Transmission over Nakagami-m Fading Channel

2015 ◽  
Vol 1 ◽  
pp. 59
Author(s):  
Nguyen Hong Giang ◽  
Vo Nguyen Quoc Bao ◽  
Hung Nguyen-Le
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Performance Metrics ◽  
Maximal Ratio Combining ◽  
Relay Nodes ◽  
Channel State ◽  
Primary Network ◽  
Secondary Network ◽  
System Designs ◽  
Approximate Expressions

This paper analyzes the performance of a cognitive underlay system over Nakagami-m fading channels, where maximal ratio combining (MRC) is employed at secondary destination and relay nodes. Under the condition of imperfect channel state information (CSI) of interfering channels, system performance metrics for the primary network and for the secondary network are formulated into exact and approximate expressions, which can be served as theoretical guidelines for system designs. To verify the performance analysis, several analytical and simulated results of the system performance are provided under various system and channel settings.

scholarly journals Multi-Points Cooperative Relay in NOMA System with N-1 DF Relaying Nodes in HD/FD Mode for N User Equipments with Energy Harvesting

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 167 ◽  
Author(s):  
Thanh-Nam Tran ◽  
Miroslav Voznak
Keyword(s):  
Energy Harvesting ◽  
Fading Channels ◽  
Interference Cancellation ◽  
Relay Node ◽  
Base Station ◽  
Cooperative Relay ◽  
Proposed Model ◽  
Excess Power ◽  
Multi Access ◽  
Near Future

Non-Orthogonal Multiple Access (NOMA) is the key technology promised to be applied in next-generation networks in the near future. In this study, we propose a multi-points cooperative relay (MPCR) NOMA model instead of just using a relay as in previous studies. Based on the channel state information (CSI), the base station (BS) selects a closest user equipment (UE) and sends a superposed signal to this UE as a first relay node. We have assumed that there are N UEs in the network and the N-th UE, which is farthest from BS, has the poorest quality signal transmitted from the BS compared the other UEs. The N-th UE received a forwarded signal from N - 1 relaying nodes that are the UEs with better signal quality. At the i-th relaying node, it detects its own symbol by using successive interference cancellation (SIC) and will forward the superimposed signal to the next closest user, namely the ( i + 1 ) -th UE, and include an excess power which will use for energy harvesting (EH) intention at the next UE. By these, the farthest UE in network can be significantly improved. In addition, closed-form expressions of outage probability for users over both the Rayleigh and Nakagami-m fading channels are also presented. Analysis and simulation results performed by Matlab software, which are presented accurately and clearly, show that the effectiveness of our proposed model and this model will be consistent with the multi-access wireless network in the future.

scholarly journals System Performance of Cooperative NOMA with Full-Duplex Relay over Nakagami-m Fading Channels

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xuan-Xinh Nguyen ◽  
Dinh-Thuan Do
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Multiple Access ◽  
Base Station ◽  
Full Duplex ◽  
Decode And Forward ◽  
Relay Systems ◽  
Channel Environment ◽  
Analytical Expressions ◽  
Dual User

In this paper, we consider a dual-user nonorthogonal multiple access (NOMA) with the help of full-duplex decode-and-forward (DF) relay systems with respect to Nakagami-m fading channel environment. Especially, we derive the analytical expressions to evaluate system performance in terms of outage probability, achievable throughput, and energy efficiency. The main investigation is on considering how the fading parameters and transmitting power at the base station make crucial impacts on system performance in the various scenarios. Finally, simulations are conducted to confirm the validity of the analysis and show the system performance of NOMA under different fading parameters of Nakagami-m fading channels.

scholarly journals Outage Probability and Ergodic Capacity of a Two-User NOMA Relaying System with an Energy Harvesting Full-Duplex Relay and Its Interference at the Near User

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6472
Author(s):  
Hoang Van Toan ◽  
Tran Manh Hoang ◽  
Tran Trung Duy ◽  
Le The Dung
Keyword(s):  
Energy Harvesting ◽  
Fading Channels ◽  
Power Distribution ◽  
Interference Cancellation ◽  
Ergodic Capacity ◽  
Base Station ◽  
Full Duplex ◽  
Distribution Factor ◽  
Relay System ◽  
Outage Probabilities

In this paper, we consider a two-user downlink full-duplex (FD) non-orthogonal multiple access (NOMA) relay system where the FD relay uses an energy harvesting (EH) technique to assist the communication between the base station and far user over flat, independent and non-identically Rayleigh fading channels. Importantly, since the relay operates in FD mode, we take into account the effect of the interference caused by relay on the near user. Considering this EH-FD-NOMA relay system, we derive the exact mathematical expressions of the outage probabilities and ergodic capacities of near and far users. Monte–Carlo simulations verify the accuracy of our analytical method. Numerical results provided in this paper allow system designers to clearly see not only the impacts of the power distribution factor and the self-interference cancellation capacity of the relay but also the influence of the strength of inter-user interference at the near user on the outage performances and ergodic capacities of both users.

scholarly journals Multi-Points Cooperative Relay in NOMA System with N-1 DF Relaying Nodes in HD/FD mode for N User Equipments with Energy Harvesting

2018 ◽  
Author(s):  
Thanh-Nam Tran ◽  
Miroslav Voznak
Keyword(s):  
Energy Harvesting ◽  
Fading Channels ◽  
Interference Cancellation ◽  
Relay Node ◽  
Base Station ◽  
Cooperative Relaying ◽  
Proposed Model ◽  
Excess Power ◽  
Multi Access ◽  
Near Future

Non-Orthogonal Multiple Access (NOMA) is the key technology promised to be applied in next-generation networks in the near future. In this study, we propose a multi-points cooperative relaying (MPCR) NOMA model instead of just using a relay as the previous studies. Based on the channel state information (CSI), the base station (BS) selects a closest user equipment (UE) and sends a superposed signal to this UE as a first relay node. We have assumed that there are N UEs in the network and Nth UE, which is farthest from BS, has the poorest quality signal transmitted from the BS compared other UEs. Nth UE received the forwarded signal from N-1 relaying nodes that are UEs with better signal quality. At the ith relaying node, it detect its own symbol by using successive interference cancellation (SIC) and will forward the composite signal to the next closest user, namely i+1th UE, and include an excess power which will use for energy harvesting (EH) intention at the next UE. By these, the farthest UE in network can be significantly improved. In addition, closed-form expressions of outage probability for users over both the Rayleigh and Nakagami-m fading channels are also presented. Analysis and simulation results performed by Matlab software which are presented accurately and clearly show that the effectiveness of our proposed model and this model consistents with the multi-access wireless network in future.

scholarly journals On secure system performance over SISO, MISO and MIMO-NOMA wireless networks equipped a multiple antenna based on TAS protocol

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Thanh-Nam Tran ◽  
Miroslav Voznak
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Interference Cancellation ◽  
Base Station ◽  
System Throughput ◽  
Experimental Investigations ◽  
Single Input Single Output ◽  
Single Antenna ◽  
Single Output ◽  
The Individual

AbstractThis study examined how to improve system performance by equipping multiple antennae at a base station (BS) and all terminal users/mobile devices instead of a single antenna as in previous studies. Experimental investigations based on three NOMA down-link models involved (1) a single-input-single-output (SISO) scenario in which a single antenna was equipped at a BS and for all users, (2) a multi-input-single-output (MISO) scenario in which multiple transmitter antennae were equipped at a BS and a single receiver antenna for all users and (3) a multi-input-multi-output (MIMO) scenario in which multiple transmitter antennae were equipped at a BS and multiple receiver antenna for all users. This study investigated and compared the outage probability (OP) and system throughput assuming all users were over Rayleigh fading channels. The individual scenarios also each had an eavesdropper. Secure system performance of the individual scenarios was therefore also investigated. In order to detect data from superimposed signals, successive interference cancellation (SIC) was deployed for users, taking into account perfect, imperfect and fully imperfect SICs. The results of analysis of users in these three scenarios were obtained in an approximate closed form by using the Gaussian-Chebyshev quadrature method. However, the clearly and accurately presented results obtained using Monte Carlo simulations prove and verify that the MIMO-NOMA scenario equipped with multiple antennae significantly improved system performance.

Outage Performance of Multiuser AF Two-Way Relaying with Asymmetric Traffic Requirements over Nakagami-m Fading

2014 ◽  
Vol 556-562 ◽  
pp. 4530-4535
Author(s):  
Shi He ◽  
Bing Gao ◽  
Zhang Jun Fan
Keyword(s):  
Monte Carlo ◽  
Outage Probability ◽  
Fading Channels ◽  
Base Station ◽  
Diversity Order ◽  
Amplify And Forward ◽  
Relay System ◽  
Outage Performance ◽  
Shed Light ◽  
Relaying System

In this paper, we investigate the outage performance of a multiuser two-way relaying system over Nakagami-m fading channels. In particular, we consider the amplify-and-forward (AF) relay system with beamforming at the base station. Furthermore, the base station and mobile users have asymmetric traffic requirements. We fist derive a tight lower bound for the outage probability (OP). Moreover, the asymptotic outage probability expression is derived to shed light on the system's diversity order. Finally, Monte Carlo simulations are conducted to verify the analytical results.

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