scholarly journals Performance Analysis of Power-Splitting Relaying Protocol in SWIPT Based Cooperative NOMA Systems

2021 ◽  
Author(s):  
Quy-Huu Tran ◽  
Ca V Phan ◽  
Quoc-Tuan Vien
Keyword(s):  
Energy Efficiency ◽  
Outage Probability ◽  
Multiple Access ◽  
Base Station ◽  
Cellular Systems ◽  
Power Splitting ◽  
Direct Link ◽  
Maximum Ratio Combining ◽  
Source Data ◽  
Simulation Results

Abstract This paper investigates a relay assisted simultaneous wireless information and power transfer (SWIPT) for downlink in cellular systems. Cooperative non-orthogonal multiple access (C-NOMA) is employed along with power splitting (PS) protocol to enable both energy harvesting (EH) and information processing (IP). A downlink model consists of a base station (BS) and two users is considered, in which the near user (NU) is selected as a relay to forward the received signal from the BS to the far user (FU). Maximum ratio combining is then employed at the FU to combine both the signals received from the BS and NU. Closed form expressions of outage propability (OP), throughput, ergodic rate and energy efficiency (EE) are firstly derived for the SWIPT based C-NOMA considering both scenarios of with and without direct link between the BS and FU. The impacts of EH time, EH efficiency, power-splitting ratio, source data rate and distance between different nodes on the performance are then investigated. The simulation results show that the C-NOMA with direct link achieves an outperformed performance over C-NOMA without direct link. Moreover, the performance of C-NOMA with direct link is also higher than that for OMA. Specifically, (i) the outage probability for C-NOMA in both direct and relaying link cases is always lower than that for OMA. (ii) the outage probability, throughput and ergodic rate vary according to β , (iii) the EE of both users can obtain in SNR range of from -10 to 5 dB and it decreases linearly as SNR increases. Numerical results are provided to verify the findings.

scholarly journals Performance analysis of power-splitting relaying protocol in SWIPT based cooperative NOMA systems

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Huu Q. Tran ◽  
Ca V. Phan ◽  
Quoc-Tuan Vien
Keyword(s):  
Energy Efficiency ◽  
Outage Probability ◽  
Multiple Access ◽  
Base Station ◽  
Cellular Systems ◽  
Power Splitting ◽  
Direct Link ◽  
Maximum Ratio Combining ◽  
Source Data ◽  
Simulation Results

AbstractThis paper investigates a relay assisted simultaneous wireless information and power transfer (SWIPT) for downlink in cellular systems. Cooperative non-orthogonal multiple access (C-NOMA) is employed along with power splitting protocol to enable both energy harvesting (EH) and information processing (IP). A downlink model consists of a base station (BS) and two users is considered, in which the near user (NU) is selected as a relay to forward the received signal from the BS to the far user (FU). Maximum ratio combining is then employed at the FU to combine both the signals received from the BS and NU. Closed form expressions of outage propability, throughput, ergodic rate and energy efficiency (EE) are firstly derived for the SWIPT based C-NOMA considering both scenarios of with and without direct link between the BS and FU. The impacts of EH time, EH efficiency, power-splitting ratio, source data rate and distance between different nodes on the performance are then investigated. The simulation results show that the C-NOMA with direct link achieves an outperformed performance over C-NOMA without direct link. Moreover, the performance of C-NOMA with direct link is also higher than that for OMA. Specifically, (1) the outage probability for C-NOMA in both direct and relaying link cases is always lower than that for OMA. (2) the outage probability, throughput and ergodic rate vary according to $$\beta$$ β , (3) the EE of both users can obtain in SNR range of from $$-10$$ - 10 to 5 dB and it decreases linearly as SNR increases. Numerical results are provided to verify the findings.

scholarly journals Performance Analysis of Power-Splitting Relaying Protocol in SWIPT Based Cooperative NOMA Systems

2020 ◽  
Author(s):  
Quy-Huu Tran ◽  
Ca V Phan ◽  
Quoc-Tuan Vien
Keyword(s):  
Energy Efficiency ◽  
Outage Probability ◽  
Multiple Access ◽  
Base Station ◽  
Cellular Systems ◽  
Power Splitting ◽  
Direct Link ◽  
Maximum Ratio Combining ◽  
Source Data ◽  
Simulation Results

Abstract This paper investigates a relay assisted simultaneous wireless information and power transfer (SWIPT) for downlink in cellular systems. Cooperative non-orthogonal multiple access (C-NOMA) is employed along with power splitting (PS) protocol to enable both energy harvesting (EH) and information processing (IP). A downlink model consisting of a base station (BS) and two users is considered, in which the near user (NU) is selected as a relay to forward the received signal from the BS to the far user (FU). Maximum ratio combining is then employed at the FU to combine both the signals received from the BS and NU. Closed form expressions of outage probability (OP), throughput, ergodic rate and energy efficiency (EE) are firstly derived for the SWIPT based C-NOMA considering both scenarios of having and without having direct link between the BS and FU. The impacts of EH time, EH efficiency, power-splitting ratio, source data rate and distance between different nodes on the performance are then investigated. The simulation results show that the C-NOMA with direct link achieves an outperformed performance over C-NOMA without direct link. Moreover, the performance of C-NOMA with direct link is also higher than that for OMA. Specifically, (i) the outage probability for C-NOMA in both direct and relaying link cases is always lower than that for OMA. (ii) the outage probability, throughput and ergodic rate vary according to b, (iii) the EE of both users can obtain in SNR range of from -10 to 5 dB and it decreases linearly as SNR increases. Numerical results are provided to verify the findings.

scholarly journals On the Performance Balancing for Uplink NOMA Systems

2020 ◽  
Vol 13 (6) ◽  
pp. 454-459
Author(s):  
Nam-Soo Kim ◽  
Keyword(s):  
Outage Probability ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Base Station ◽  
Cellular Systems ◽  
Mobile Cellular ◽  
Noise Ratio ◽  
Outage Probabilities ◽  
Error Floors

Outage probability and capacity are the representative performance measures for the quality of service (QoS) in mobile cellular systems. Recently, power back-off scheme is proposed in uplink non-orthogonal multiple access (NOMA) systems. The power back-off scheme improves the performance of a near user, however, decreases that of a far user. In comparison, the scheme indicates the error floors with an outage probability of 2.4×〖10〗^(-1) and 9.1×〖10〗^(-2) with power back-off 5 dB and 10 dB, respectively under the specified condition. To address these drawbacks, we propose an equal average signal-to–interference plus noise ratio (SINR) scheme that derives the same average SINR from active users at the base station (BS) in uplink non-orthogonal multiple access (NOMA) systems. Numerical results show that required signal-to-noise ratio (SNR) for the outage probability of 1×〖10〗^(-3) of the near and far users are close enough within 1 dB, which means an outage balance between two users. And it is noticed that the outage probabilities in the proposed scheme decrease as the increase of the received SNR without error floors. Also, different from the power back-off scheme, we noticed that the capacities of the two users in the proposed scheme are coincident and increase with SNR. The outage probabilities and ergodic capacity of the near and far users are derived in closed-form expressions. The analytical results are conformed by Monte Carlo simulation.

scholarly journals Performance Analysis of Cooperative NOMA Networks with Imperfect CSI over Nakagami-m Fading Channels

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 424 ◽  
Author(s):  
Xianli Gong ◽  
Xinwei Yue ◽  
Feng Liu
Keyword(s):  
Outage Probability ◽  
Fading Channels ◽  
Multiple Access ◽  
Base Station ◽  
High Signal ◽  
Direct Link ◽  
Decode And Forward ◽  
Estimation Errors ◽  
Channel Estimation Errors ◽  
Outage Performance

In this paper, we investigate a downlink cooperative non-orthogonal multiple access (NOMA) network with decode-and-forward relaying, where two scenarios of user relaying with direct link and user relaying without direct link are discussed in detail. More particularly, the performance of cooperative NOMA system under the assumption of imperfect channel state information (ipCSI) is studied over Nakagami-m fading channels. To evaluate the outage performance of the above discussed two scenarios, the closed-form expressions of outage probability for a pair of users are derived carefully. The diversity orders of users are achieved in the high signal-to-noise region. An error floor appears in the outage probability owing to the existence of channel estimation errors under ipCSI conditions. Simulation results verify the validity of our analysis and show that: (1) NOMA is superior to conventional orthogonal multiple access; (2) The best user relaying location for cooperative NOMA networks should be near to the base station; and (3) The outage performance of distant user with direct link significantly outperforms distant user without direct link by comparing the two scenarios.

scholarly journals ENERGY-EFFICIENT POWER ALLOCATION FOR IMPERFECT CSI DOWNLINK NOMA SYSTEM

2021 ◽  
Vol 11 (2) ◽  
pp. 118-129
Author(s):  
Reem Aldebes ◽  
Kaharudin Dimyati ◽  
Effariza Hanafi
Keyword(s):  
Energy Efficiency ◽  
Channel Estimation ◽  
Outage Probability ◽  
Power Allocation ◽  
Multiple Access ◽  
Estimation Error ◽  
Base Station ◽  
Channel Estimation Error ◽  
Imperfect Csi ◽  
Fifth Generation

The fifth generation (5G) networks must provide the massively increased number of users by thousand times higher data rate at lower power consumption. Thus, optimizing the energy efficiency (EE) becomes an essential issue that has to be researched from the green communication perspective. Non-orthogonal multiple access (NOMA) is considered one of the high potential techniques in fifth-generation systems. This technology is favorable to maximize the energy efficiency and the spectrum efficiency by composing different signals at the same time on the same carrier at different power levels. In this paper, a low complexity power allocation algorithm is proposed in imperfect channel state information (CSI) downlink NOMA cellular system, where obtaining full CSI at the base station is considered a challenge. The proposed algorithm relies on the fact that the allocated power is inversely proportional to the channel strength of the user to implement the successive interference cancellation (SIC) technique at the user terminal to reconstruct the desired signal. The performance of the system is analyzed in terms of energy efficiency and outage probability and compared to the conventional orthogonal multiple access (OMA) system. Results show that the proposed algorithm increases the energy efficiency by about 50% compared to the conventional OMA technology, and an improvement in the outage probability has been achieved. Furthermore, the effect of the error in the channel estimation on the energy efficiency in imperfect CSI NOMA system is evaluated. The simulation shows that the energy efficiency reduces when the channel estimation error increases; and the best performance is achieved in the perfect CSI case where the channel estimation error is zero.

scholarly journals Massive MIMO: Achievable Energy Efficiency for 5G systems with Multi-user Environment

2019 ◽  
Vol 8 (2) ◽  
pp. 6527-6534
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Path Loss ◽  
Antenna System ◽  
Base Station ◽  
Small Cells ◽  
Limiting Factors ◽  
Improve Energy Efficiency ◽  
User Terminal ◽  
Simulation Results

Massive Multi-Input and Multi-Output (MIMO) antenna system potentially provides a promising solution to improve energy efficiency (EE) for 5G wireless systems. The aim of this paper is to enhance EE and its limiting factors are explored. The maximum EE of 48 Mbit/Joule was achieved with 15 user terminal (UT)s. This problem is related to the uplink spectral efficiency with upper bound for future wireless networks. The maximal EE is obtained by optimizing a number of base station (BS) antennas, pilot reuse factor, and BSs density. We presented a power consumption model by deriving Shannon capacity calculations with closed-form expressions. The simulation result highlights the EE maximization with optimizing variables of circuit power consumption, hardware impairments, and path-loss exponent. Small cells achieve high EE and saturate to a constant value with BSs density. The MRC scheme achieves maximum EE of 36 Mbit/Joule with 12 UTs. The simulation results show that peak EE is obtained by deploying massive BS antennas, where the interference and pilot contamination are mitigated by coherent processing. The simulation results were implemented by using MATLAB 2018b.

scholarly journals A Coordinated Direct AF/DF Relay-Aided NOMA Framework for Low Outage

2021 ◽  
Author(s):  
Anand Jee ◽  
KAMAL AGRAWAL ◽  
Shankar Prakriya
Keyword(s):  
Energy Efficiency ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Outage Probability ◽  
Closed Form ◽  
Power Allocation ◽  
Multiple Access ◽  
Performance Gain ◽  
Amplify And Forward ◽  
Decode And Forward

This paper investigates the performance of a framework for low-outage downlink non-orthogonal multiple access (NOMA) signalling using a coordinated direct and relay transmission (CDRT) scheme with direct links to both the near-user (NU) and the far-user (FU). Both amplify-and-forward (AF) and decode-and-forward (DF) relaying are considered. In this framework, NU and FU combine the signals from BS and R to attain good outage performance and harness a diversity of two without any need for feedback. For the NU, this serves as an incentive to participate in NOMA signalling. For both NU and FU, expressions for outage probability and throughput are derived in closed form. High-SNR approximations to the outage probability are also presented. We demonstrate that the choice of power allocation coefficient and target rate is crucial to maximize the NU performance while ensuring a desired FU performance. We demonstrate performance gain of the proposed scheme over selective decode-and-forward (SDF) CDRT-NOMA in terms of three metrics: outage probability, sum throughput and energy efficiency. Further, we demonstrate that by choosing the target rate intelligently, the proposed CDRT NOMA scheme ensures higher energy efficiency (EE) in comparison to its orthogonal multiple access counterpart. Monte Carlo simulations validate the derived expressions.

scholarly journals Clustering and Auction-Based Power Allocation Algorithm for Energy Efficiency Maximization in Multi-Cell Multi-Carrier NOMA Networks

2019 ◽  
Vol 9 (23) ◽  
pp. 5034 ◽  
Author(s):  
Abuzar B. M. Adam ◽  
Xiaoyu Wan ◽  
Zhengqiang Wang
Keyword(s):  
Energy Efficiency ◽  
Power Allocation ◽  
Cooperative Game ◽  
Multiple Access ◽  
Optimization Problem ◽  
Interference Mitigation ◽  
Base Stations ◽  
Frequency Division ◽  
Simulation Results ◽  
Inter Cell Interference

In this paper, we investigate the energy efficiency (EE) maximization in multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) networks. To achieve this goal, an optimization problem is formulated then the solution is divided into two parts. First, we investigate the inter-cell interference mitigation and then we propose an auction-based non-cooperative game for power allocation for base stations. Finally, to guarantee the rate requirements for users, power is allocated fairly to users. The simulation results show that the proposed scheme has the best performance compared with the existing NOMA-based fractional transmit power allocation (FTPA) and the conventional orthogonal frequency division multiple access (OFDMA).

scholarly journals A Coordinated Direct AF/DF Relay-Aided NOMA Framework for Low Outage

2021 ◽  
Author(s):  
Anand Jee ◽  
KAMAL AGRAWAL ◽  
Shankar Prakriya
Keyword(s):  
Energy Efficiency ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Outage Probability ◽  
Closed Form ◽  
Power Allocation ◽  
Multiple Access ◽  
Performance Gain ◽  
Amplify And Forward ◽  
Decode And Forward

This paper investigates the performance of a framework for low-outage downlink non-orthogonal multiple access (NOMA) signalling using a coordinated direct and relay transmission (CDRT) scheme with direct links to both the near-user (NU) and the far-user (FU). Both amplify-and-forward (AF) and decode-and-forward (DF) relaying are considered. In this framework, NU and FU combine the signals from BS and R to attain good outage performance and harness a diversity of two without any need for feedback. For the NU, this serves as an incentive to participate in NOMA signalling. For both NU and FU, expressions for outage probability and throughput are derived in closed form. High-SNR approximations to the outage probability are also presented. We demonstrate that the choice of power allocation coefficient and target rate is crucial to maximize the NU performance while ensuring a desired FU performance. We demonstrate performance gain of the proposed scheme over selective decode-and-forward (SDF) CDRT-NOMA in terms of three metrics: outage probability, sum throughput and energy efficiency. Further, we demonstrate that by choosing the target rate intelligently, the proposed CDRT NOMA scheme ensures higher energy efficiency (EE) in comparison to its orthogonal multiple access counterpart. Monte Carlo simulations validate the derived expressions.

scholarly journals A Framed Slotted ALOHA-Based MAC for Eliminating Vain Wireless Power Transfer in Wireless Powered IoT Networks

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Ying-Jen Lin ◽  
Show-Shiow Tzeng
Keyword(s):  
Multiple Access ◽  
Time Slot ◽  
Base Station ◽  
Full Duplex ◽  
Wireless Power ◽  
Slotted Aloha ◽  
Data Packets ◽  
Half Duplex ◽  
Framed Slotted Aloha ◽  
Simulation Results

Multiple access control (MAC) is crucial for devices to send data packets and harvest wireless energy in wireless powered Internet of Things (IoT) networks. A framed slotted ALOHA (FSA) protocol is employed in several practical networks. This paper studies an FSA-based MAC in a centralized wireless powered IoT network, including half-duplex devices and a full-duplex base station transmitting wireless energy in an intended direction. Under such a network, it is possible that a half-duplex device contends for a time slot to transmit a packet while the base station transmits wireless energy to the device in the same time slot, which causes vain charging and wastes the opportunity to charge other devices. To eliminate the vain charging, this paper designs a MAC in which a base station utilizes the information conveyed from devices in advance to arrange the charging order of devices. The novelty is to develop an algorithm to find a charging order of half-duplex devices instead of using full-duplex devices to eliminate the vain charging. Event-driven simulations are conducted to study the performance of the proposed MAC. Simulation results show that the proposed MAC produces better system performances than the system not eliminating the vain charging. In summary, the application of the proposed MAC yields the benefits of higher throughput and lower packet loss.

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