Improving performance of far users in cognitive radio: Exploiting NOMA and wireless power transfer

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.Web of Science1211art. no. 220

Enabling non-linear energy harvesting in power domain based multiple access in relaying networks: Outage and ergodic capacity performance analysis

The Power Domain-based Multiple Access (PDMA) scheme is considered as one kind of Non-Orthogonal Multiple Access (NOMA) in green communications and can support energy-limited devices by employing wireless power transfer. Such a technique is known as a lifetime-expanding solution for operations in future access policy, especially in the deployment of power-constrained relays for a three-node dual-hop system. In particular, PDMA and energy harvesting are considered as two communication concepts, which are jointly investigated in this paper. However, the dual-hop relaying network system is a popular model assuming an ideal linear energy harvesting circuit, as in recent works, while the practical system situation motivates us to concentrate on another protocol, namely non-linear energy harvesting. As important results, a closed-form formula of outage probability and ergodic capacity is studied under a practical non-linear energy harvesting model. To explore the optimal system performance in terms of outage probability and ergodic capacity, several main parameters including the energy harvesting coefficients, position allocation of each node, power allocation factors, and transmit signal-to-noise ratio (SNR) are jointly considered. To provide insights into the performance, the approximate expressions for the ergodic capacity are given. By matching analytical and Monte Carlo simulations, the correctness of this framework can be examined. With the observation of the simulation results, the figures also show that the performance of energy harvesting-aware PDMA systems under the proposed model can satisfy the requirements in real PDMA applications.Web of Science87art. no. 81

Rendements d’utilisation et consommation d’énergie au Québec

The concept of useful energy consumption has been used by some authors by weighting observed energy consumptions. It is argued in this paper that the weights should not be the regression parameter estimates of the GNP on various forms of energy consumptions as they are now, but they should be the mechanical use efficiency of each energy form. A number of functional forms of the GNP are then obtained, all very good from the econometric viewpoint. Finally, it is pointed out that the rate of substitution between different forms of energy does depend on the functional form of the GN

Factors Affecting Credit Growth of Vietnamese Commercial Banks

This research analyzes the factors that affect the credit growthof the Vietnamese commercial banking system. This study usedata from the annual reports and financial statements of 16commercial banks listed on the HOSE, HNX, and UPCOMexchanges that have operated continuously from 2011 to 2020.Two linear regression models were employed with two dependentvariables: the credit growth rate and credit size. The findingsindicate that credit size in the previous period, the annualgrowth rate of capital mobilization, bank size, and return onassets (ROA) positively affect the credit growth of Vietnamesecommercial banks while liquidity ratio negatively affects them.Also, the bad debt ratio’s effect on credit growth is unclear. Hence,some suggestions and recommendations are given for commercialbanks to maintain stable, safe, and sustainable credit growth.JEL Classification: G21, E50, E5

The Stochastic Finite Element in the Natural Frequency of Functionally Graded Material Beams

In this study, the stochastic finite element solution is given to obtain the variability in the natural frequency of functionally graded material (FGM) beam. The elastic modulus is assumed to vary in the thickness direction and the width of the beam to vary as well in the longitudinal direction following the exponential law. The random material properties of elastic modulus and mass density of the FGM beam are assumed to be one-dimensional homogeneous stochastic processes. The stochastic finite element analysis of FGM beam is performed in conjunction with Monte Carlo simulation (MCS) employing the spectral representation method for 16, the description of random processes of the random material properties under consideration. The response variability of the natural frequency due to random elastic modulus is evaluated for various states of randomness. Furthermore, the investigation on the effect of the correlation between random elastic modulus and random mass density on the response variability is addressed in detail as well

Rendements d’utilisation et consommation d’énergie au Québec

The concept of useful energy consumption has been used by some authors by weighting observed energy consumptions. It is argued in this paper that the weights should not be the regression parameter estimates of the GNP on various forms of energy consumptions as they are now, but they should be the mechanical use efficiency of each energy form. A number of functional forms of the GNP are then obtained, all very good from the econometric viewpoint. Finally, it is pointed out that the rate of substitution between different forms of energy does depend on the functional form of the GNP

Tractable computation in outage performance analysis of relay selection NOMA

In recent years, using full-duplex (FD) transmission model provides enhanced bandwidth efficiency and improved performance for non-orthogonal multiple access (NOMA) system. However, lack of papers have investigated FD relay together with relay selection issue to improve performance of NOMA system. The problems in power allocation for two NOMA users satisfying fairness as well as relay selection strategy are studied in this paper. By considering the outage performance of proposed scheme with its vital result, general NOMA wireless networks can be developed for future networks due to its improved performance. Simulation results show that the relaying selection scheme can achieve a significant performance improvement by increasing required quantity of relay

Performance of downlink NOMA with multiple antenna base station, full-duplex and D2D transmission

The implementation of non-orthogonal multiple access (NOMA) and transmit antenna selection (TAS) technique has considered in this paper since TAS-aware base station (BS) provides the low cost, low complexity, and high diversity gains. In this paper, we investigate performance of two users by deriving outage probability. The system performance benefits from design of TAS and full-duplex (FD) scheme applied at NOMA users, and bandwidth efficiency will be enhanced although self-interference exists due to FD. The main contribution lies in the exact expressions of outage probability which are derived to exhibit system performance. Different from the simulated parameters, the analytical results show that increasing number of transmit antennas at the BS is way to improve system performance