scholarly journals Cognitive Radio-Assisted NOMA Broadcasting for 5G Cellular V2X Communications: Model of Roadside Unit Selection and SWIPT

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1786
Author(s):  
Dinh-Thuan Do ◽  
Anh-Tu Le ◽  
Thi-Anh Hoang ◽  
Byung Moo Lee
Keyword(s):  
Cognitive Radio ◽  
System Performance ◽  
Multiple Access ◽  
Unit Selection ◽  
Performance Simulation ◽  
Selection Scheme ◽  
Outage Performance ◽  
Battery Capacity ◽  
Rf Signals ◽  
Roadside Unit

The outage performance is a significant problem to implement the Cognitive Radio (CR) paradigm in the Vehicle to Everything (V2X) networks. Recently, more interest has focused on Non-Orthogonal Multiple Access (NOMA) in wireless-powered communication. In the conventional CR-enabled V2X-NOMA network, spectrum sensing and limited battery capacity at the Roadside Unit (RSU) may cause serious outage performance. In this study, RSU selection scheme is adopted. This paper presents an interesting model of a system with Simultaneous Wireless Information and Power Transfer (SWIPT) and a CR-enabled V2X-NOMA network. In the downlink, the RSU harvests wireless energy from Radio Frequency (RF) signals and senses the spectrum state at the same time. A CR-enabled V2X-NOMA system performance is presented by deriving exact expressions of outage probability of distant vehicles. In the overlay CR-enabled V2X-NOMA network, the constraints are transmit power and the number of designed RSU that make significant impacts on system performance. Simulation results show that the CR-enabled V2X-NOMA get benefits from energy harvesting and RSU selection scheme.

scholarly journals Exploiting outage performance in device-to-device for user grouping

2021 ◽  
Vol 24 (2) ◽  
pp. 904
Author(s):  
Dinh-Thuan Do ◽  
Chi-Bao Le
Keyword(s):  
System Performance ◽  
Multiple Access ◽  
Base Station ◽  
Spectrum Efficiency ◽  
Frame Structure ◽  
Outage Performance ◽  
User Grouping ◽  
Numerical Result ◽  
Device To Device ◽  
New Form

The spectrum efficiency and massive connections are joint designed in new form of device-to-device for user grouping. A pair of users is implemented with nonorthogonal multiple access (NOMA) systems. Although NOMA benefits to such system in term of the serving users, device to device (D2D) faces the interference from normal cellular users (CUE). In particular, we derive exact formulas of outage probability to show system performance. In this article, we compare two schemes to find relevant scheme to implement in practice. The frame structure is designed with two timeslot related to uplink and downlink between the base station and D2D users. We confirm the better scheme in numerical result by considering the impacts of many parameters on outage performance.

scholarly journals Non-Orthogonal Multiple Access Assisted Device-to-Device Communication: Best Helping Base Station Approach

2018 ◽  
Vol 12 (2) ◽  
pp. 803
Author(s):  
Huu-Phuc Dang ◽  
Minh-Sang Nguyen ◽  
Dinh-Thuan Do
Keyword(s):  
Data Transmission ◽  
System Performance ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Selection Scheme ◽  
Channel Condition ◽  
Expected Performance ◽  
Realistic Assumption ◽  
Device To Device

<span>It can be studied in this paper that a cooperative non-orthogonal multiple access (NOMA) helps device-to-device (D2D) communication system through base station (BS). In particular, we investigate BS selection scheme as a best channel condition for dedicated devices where a different data transmission demand on each device is resolved. The analysis on amplifying-and forward (AF) relay is proposed to evaluate system performance of the conventional cooperative NOMA scheme. Under the realistic assumption of perfect channel estimation, the achievable outage probability of both devices is investigated, and several impacts on system performance are presented. The mathematical formula in closed form related to probability has also been found. By implementing Monte-Carlo simulation, the simulation results confirm the accuracy of the derived analytical results. Also, the proposed D2D cooperative NOMA system introduces expected performance on reasonable selected parameters in the moderate signal to noise ratio (SNR) regime.</span>

scholarly journals On Exact Outage and Throughput Performance of Cognitive Radio based Non-Orthogonal Multiple Access Networks With and Without D2D Link

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3314 ◽  
Author(s):  
Dinh-Thuan Do ◽  
Anh-Tu Le ◽  
Chi-Bao Le ◽  
Byung Moo Lee
Keyword(s):  
Cognitive Radio ◽  
Power Allocation ◽  
Multiple Access ◽  
Signal Transmission ◽  
Outage Performance ◽  
System A ◽  
Primary Network ◽  
Secondary Network ◽  
Fixed Power ◽  
Analytical Expressions

In this paper, we investigate the performance of a secondary network in a cognitive radio network employing a non-orthogonal multiple access (NOMA) scheme to form a CR-NOMA system serving many destination users. In the secondary network of our proposed system, a device-to-device (D2D) scheme is deployed to further provide the signal transmission at a close distance of NOMA users in downlink, and such performance is evaluated under the situation of interference reception from the primary network. An outage performance gap exists among these NOMA users since different power allocation factors are assigned to the different destinations. Unlike existing NOMA schemes that consider fixed power allocation factors, which are not optimal in terms of outage performance, our proposed paradigm exhibits optimal outage in the scenario of D2D transmission. In particular, the outage performances in two kinds of schemes in term of existence of D2D link are further achieved. Simulation results validate the analytical expressions, and show the advantage of each scheme in the proposed CR-NOMA system based on outage performance and throughput.

Relay Selection-aware Non-orthogonal Multiple Access Networks: Direct and Relaying Mode

2020 ◽  
Vol 13 (3) ◽  
pp. 348-354
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang V. Nguyen
Keyword(s):  
Relay Selection ◽  
Multiple Access ◽  
Decode And Forward ◽  
Selection Scheme ◽  
Fixed Power ◽  
Transmission Quality ◽  
Improved Performance ◽  
Outage Probabilities ◽  
Future Work ◽  
The Impact

Objective: In this paper, Decode-and-Forward (DF) mode is deployed in the Relay Selection (RS) scheme to provide better performance in cooperative downlink Non-orthogonal Multiple Access (NOMA) networks. In particular, evaluation regarding the impact of the number of multiple relays on outage performance is presented. Methods: As main parameter affecting cooperative NOMA performance, we consider the scenario of the fixed power allocations and the varying number of relays. In addition, the expressions of outage probabilities are the main metric to examine separated NOMA users. By matching related results between simulation and analytical methods, the exactness of derived formula can be verified. Results: The intuitive main results show that in such cooperative NOMA networks, the higher the number of relays equipped, the better the system performance can be achieved. Conclusion: DF mode is confirmed as a reasonable selection scheme to improve the transmission quality in NOMA. In future work, we will introduce new relay selections to achieve improved performance.

scholarly journals Multiple Access in Cognitive Radio Networks: From Orthogonal and Non-Orthogonal to Rate-Splitting

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Safaa Gamal ◽  
Mohamed Rihan ◽  
Saleh Hussin ◽  
Adel Zaghloul ◽  
A. Abdelaziz Salem
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Multiple Access ◽  
Radio Networks ◽  
Rate Splitting
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