scholarly journals Amplify-forward and decode-forward: a novel power allocation technique for MIMO cognitive radio network

2018 ◽  
Vol 7 (3.3) ◽  
pp. 670
Author(s):  
M Monisha ◽  
M Meena ◽  
C Sharanya ◽  
T Jaya
Keyword(s):  
Cognitive Radio ◽  
Power Allocation ◽  
Communication Channel ◽  
Signal To Noise Ratio ◽  
Input Power ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Radio System ◽  
Wireless Medium ◽  
Efficient Power

Nowadays transmitting data through wireless communication channel requires more power than the wired communication channel. In other words any communication through wireless medium will consume more power. Since power is a limited source, it is hard to conserve it or reduce its usage and this leads to the concept of “Efficient power allocation scheme for MIMO (Multi Input Multi Output) cognitive radio” system. The proposed system uses two algorithms namely On/Off Based Scheduling (OOBS) and Selective Based Scheduling (SBS) in Amplify and Forward (AAF) and Decode and Forward (DAF) techniques. OOBS algorithm is used for efficient allocation of the input power to each user’s Signal to Noise Ratio (SNR) value. The proposed algorithm provides better power utilization with low bit error rate (9.53×10-7).  

scholarly journals Improving Performance of Far Users in Cognitive Radio: Exploiting NOMA and Wireless Power Transfer

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2206 ◽  
Author(s):  
Minh-Sang Van Nguyen ◽  
Dinh-Thuan Do ◽  
Miroslav Voznak
Keyword(s):  
Cognitive Radio ◽  
Energy Harvesting ◽  
Power Allocation ◽  
Signal To Noise Ratio ◽  
Selection Strategy ◽  
Amplify And Forward ◽  
Outage Performance ◽  
Main Observation ◽  
Relaying Systems ◽  
Single Relay

In this paper, we examine non-orthogonal multiple access (NOMA) and relay selection strategy to benefit extra advantage from traditional cognitive radio (CR) relaying systems. The most important requirement to prolong lifetime of such network is employing energy harvesting in the relay to address network with limited power constraint. In particular, we study such energy harvesting CR-NOMA using amplify-and-forward (AF) scheme to improve performance far NOMA users. To further address such problem, two schemes are investigated in term of number of selected relays. To further examine system performance, the outage performance needs to be studied for such wireless powered CR-NOMA network over Rayleigh channels. The accurate expressions for the outage probability are derived to perform outage comparison of primary network and secondary network. The analytical results show clearly that position of these nodes, transmit signal to noise ratio (SNR) and power allocation coefficients result in varying outage performance. As main observation, performance gap between primary and secondary destination is decided by both power allocation factors and selection mode of single relay or multiple relays. Numerical studies were conducted to verify our derivations.

scholarly journals The Effect of Misdetection Probability on the Performance of Cooperative-Relaying-Based Cognitive Radio Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Ning Cao ◽  
Yuchang Ye ◽  
Minghe Mao
Keyword(s):  
Cognitive Radio ◽  
Outage Probability ◽  
Power Allocation ◽  
Cooperative Relaying ◽  
Channel Gain ◽  
Practical Implementation ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Af Relaying ◽  
Allocation Factor

Cognitive radio (CR) is a promising solution to address the more and more congested radio spectrum. Cooperative relaying can provide a better transmission performance for the secondary user (SU), while the performance of the primary user (PU, also named licensed user) should be preferentially protected especially when there is misdetection probability. In this paper, in order to keep the PU away from outage caused by the interference from the SU under a certain signal-to-noise ratio (SNR), the maximum SNR for the SU can be derived by using the rate decaying factor (RDF). Then, based on the maximum channel gain and the maximum SNR, the outage probability is analyzed using decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying schemes. Numerical results show that the outage probability decreases when the power allocation factor increases for DF strategy, while the outage probability has error floor when the power allocation factor increases for AF strategy. And the relaying scheme based on the maximum channel gain outperforms that based on the maximum SNR when the power allocation factor and detection probability are small, while the relaying scheme based on the maximum SNR outperforms that based on the maximum channel gain when the power allocation factor is large. What is more, AF relaying has better outage performance in the practical implementation.

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.

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