scholarly journals PEP Analysis of AF Relay NOMA Systems Employing Order Statistics of Cascaded Channels

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 695 ◽  
Author(s):  
Suyue Li ◽  
Anhong Wang ◽  
Jie Liang
Keyword(s):  
Closed Form ◽  
Order Statistics ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Series Representation ◽  
Modified Bessel Function ◽  
Error Performance ◽  
System Parameters ◽  
Cascaded Channels

The precise error performance analysis is challenging for non-orthogonal multiple access (NOMA) systems due to nonlinear successive interference cancellation (SIC) processing among NOMA users. In this paper, the pairwise error probability (PEP) performance of different users is investigated for relay NOMA simultaneous wireless information and power transfer (SWIPT) systems. By employing the order statistics theory, we obtain the ordered probability density function of the cascaded channel through Source-to-Relay-to-User links. Then we derive the analytical closed-form PEP expressions for NOMA users. To obtain the approximate closed-form PEP, we explore the finite series representation of the power of the modified Bessel function to replace the integrand terms. Monte Carlo simulation results show that the approximate analytical PEP of each user is basically in agreement with the simulated PEP. Furthermore, on the basis of the closed-form PEP, the influence of relevant system parameters on the error performance is examined via numerical simulations, which manifests that the choice of power allocation coefficients should be balanced between the users’ channel conditions and the demanded quality of service.

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

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.

scholarly journals Exact Bit Error-Rate Analysis of Two-User NOMA Using QAM with Arbitrary Modulation Orders

2020 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Tasneem Assaf ◽  
Mohamed El Moursi ◽  
Hatem Zein El din ◽  
Mohammad Al-Jarrah
Keyword(s):  
Closed Form ◽  
Power Allocation ◽  
General Expression ◽  
Bit Error Rate ◽  
Error Rate ◽  
Amplitude Modulation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Rate Analysis ◽  
Multiuser Detector

This work considers the exact bit error rate (BER) analysis of a two-user non-orthogonal multiple access (NOMA) system using quadrature amplitude modulation (QAM). Unlike existing work, no constraints on the modulation order of the QAM symbols for any user. Closed-form expressions are derived for the BER of joint multiuser detector (JMuD), which is demonstrated that it is equivalent to the successive interference cancellation (SIC) receiver. Moreover, a general expression is derived for the relation between the power allocation factors for the two users, which depends on the modulation order for each user.

scholarly journals Power Allocation for Reliable SIC Detection of Rectangular QAM-based NOMA Systems

2021 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Youssef Iraqi
Keyword(s):  
Power Allocation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Arbitrary Order ◽  
Search Space ◽  
Brute Force ◽  
Power Assignment ◽  
Error Performance ◽  
Optimal Power ◽  
Power Difference

This paper considers the power allocation for non-orthogonal multiple access (NOMA) users to enable using the successive interference cancellation (SIC) while providing reliable error performance. The derived closed-form expressions are applicable for arbitrary number of NOMA users each of which has a square or rectangular quadrature amplitude modulation (QAM) constellation with arbitrary order. The obtained numerical results show that power assignment process at the transmitter for the superposition process and at the receiver for the SIC process should be performed meticulously because the power difference between the weakest and strongest users can be tremendous when the number of users or the modulation orders increase. Moreover, the derived expressions can be used to reduce the computational complexity that is required to obtain the optimal power coefficients using brute force methods by significantly reducing the search space.

scholarly journals Performance Analysis of IRS-Aided NOMA Communications in the Presence of Imperfect SIC

2021 ◽  
Vol 21 (5) ◽  
pp. 341-350
Author(s):  
Van Phu Tuan ◽  
Ic-Pyo Hong
Keyword(s):  
Energy Efficiency ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Performance Metrics ◽  
Promising Technique ◽  
System Parameters ◽  
Target Performance ◽  
Reflecting Surface ◽  
Theoretical Results ◽  
Imperfection Factor

The intelligent reflecting surface (IRS) is expected to be a promising technique to achieve a robust spectrum and energy efficiency. This paper investigates the advantages of IRS in enhancing performance of non-orthogonal multiple access (NOMA) communications in the presence of imperfect successive-interference-cancellation (SIC) and phase distortion (PD) caused by a non-ideal IRS. Specifically, average achievable rates (AARs) of the users are the target performance metrics. For performance evaluation, the probabilistic characterizations of signal-to-interference-plus-noise ratios (SINRs) at the users are studied. These results allow for deriving the theoretical formulas for the AAR. Monte Carlo simulations are adopted to verify the accuracy of these theoretical results. The numerical results show the effects of various key system parameters, such as source transmit power, NOMA power allocation (PA) factors, reflecting tile (RTs) allocation, the SIC imperfection factor, and the PD factor, on the AAR that provide useful information for the system’s design.

scholarly journals Power Allocation for Reliable SIC Detection of Rectangular QAM-based NOMA Systems

2021 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Youssef Iraqi
Keyword(s):  
Power Allocation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Arbitrary Order ◽  
Search Space ◽  
Brute Force ◽  
Power Assignment ◽  
Error Performance ◽  
Optimal Power ◽  
Power Difference

This paper considers the power allocation for non-orthogonal multiple access (NOMA) users to enable using the successive interference cancellation (SIC) while providing reliable error performance. The derived closed-form expressions are applicable for arbitrary number of NOMA users each of which has a square or rectangular quadrature amplitude modulation (QAM) constellation with arbitrary order. The obtained numerical results show that power assignment process at the transmitter for the superposition process and at the receiver for the SIC process should be performed meticulously because the power difference between the weakest and strongest users can be tremendous when the number of users or the modulation orders increase. Moreover, the derived expressions can be used to reduce the computational complexity that is required to obtain the optimal power coefficients using brute force methods by significantly reducing the search space.

scholarly journals Power Allocation for Reliable SIC Detection of Rectangular QAM-based NOMA Systems

2021 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Youssef Iraqi
Keyword(s):  
Power Allocation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Arbitrary Order ◽  
Search Space ◽  
Brute Force ◽  
Power Assignment ◽  
Error Performance ◽  
Optimal Power ◽  
Power Difference

This paper considers the power allocation for non-orthogonal multiple access (NOMA) users to enable using the successive interference cancellation (SIC) while providing reliable error performance. The derived closed-form expressions are applicable for arbitrary number of NOMA users each of which has a square or rectangular quadrature amplitude modulation (QAM) constellation with arbitrary order. The obtained numerical results show that power assignment process at the transmitter for the superposition process and at the receiver for the SIC process should be performed meticulously because the power difference between the weakest and strongest users can be tremendous when the number of users or the modulation orders increase. Moreover, the derived expressions can be used to reduce the computational complexity that is required to obtain the optimal power coefficients using brute force methods by significantly reducing the search space.

scholarly journals Exact Bit Error-Rate Analysis of Two-User NOMA Using QAM with Arbitrary Modulation Orders

2020 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Tasneem Assaf ◽  
Mohamed El Moursi ◽  
Hatem Zein El din ◽  
Mohammad Al-Jarrah
Keyword(s):  
Closed Form ◽  
Power Allocation ◽  
General Expression ◽  
Bit Error Rate ◽  
Error Rate ◽  
Amplitude Modulation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Rate Analysis ◽  
Multiuser Detector

This work considers the exact bit error rate (BER) analysis of a two-user non-orthogonal multiple access (NOMA) system using quadrature amplitude modulation (QAM). Unlike existing work, no constraints on the modulation order of the QAM symbols for any user. Closed-form expressions are derived for the BER of joint multiuser detector (JMuD), which is demonstrated that it is equivalent to the successive interference cancellation (SIC) receiver. Moreover, a general expression is derived for the relation between the power allocation factors for the two users, which depends on the modulation order for each user.

scholarly journals Power Allocation for Reliable SIC Detection of Rectangular QAM-based NOMA Systems

2021 ◽  
Author(s):  
Arafat Al-Dweik ◽  
Youssef Iraqi
Keyword(s):  
Power Allocation ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Arbitrary Order ◽  
Search Space ◽  
Brute Force ◽  
Power Assignment ◽  
Error Performance ◽  
Optimal Power ◽  
Power Difference

This paper considers the power allocation for non-orthogonal multiple access (NOMA) users to enable using the successive interference cancellation (SIC) while providing reliable error performance. The derived closed-form expressions are applicable for arbitrary number of NOMA users each of which has a square or rectangular quadrature amplitude modulation (QAM) constellation with arbitrary order. The obtained numerical results show that power assignment process at the transmitter for the superposition process and at the receiver for the SIC process should be performed meticulously because the power difference between the weakest and strongest users can be tremendous when the number of users or the modulation orders increase. Moreover, the derived expressions can be used to reduce the computational complexity that is required to obtain the optimal power coefficients using brute force methods by significantly reducing the search space.

UNDER-GRADUATE STUDENTS AND THE ROLE OF E- LIBRARIES TO UPLIFT THE QUALITY OF HIGHER EDUCATION

2018 ◽  
Vol 6 (26) ◽  
Author(s):  
Dharambeer Singh
Keyword(s):  
Graduate Students ◽  
Digital Libraries ◽  
Rural Areas ◽  
Multiple Access ◽  
Information Needs ◽  
Quality Of Higher Education ◽  
Brick And Mortar ◽  
Education Status

Digital libraries, designed to serve people and their information needs in the same way as traditional libraries, present distinct advantages over brick and mortar facilities: elimination of physical boundaries, round-the-clock access to information, multiple access points, networking abilities, and extended search functions. As a result, they should be especially well-suited for the disables. However, minorities, those affected by lower income and education status, persons living in rural areas, the physically challanged, and developing countries as a whole consistently suffer from a lack of accessibility to digital libraries. This paper evaluates the effectiveness and relevance of digital libraries currently in place and discusses what could and should be done to improve accessibility to digital libraries for under-graduate students.

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