scholarly journals Adaptive Relay Selection Scheme by Using Compound Channel

2020 ◽  
Vol 10 (16) ◽  
pp. 5614
Author(s):  
Yu-Jin Na ◽  
Won-Seok Lee ◽  
Min-Jae Paek ◽  
Hyoung-Kyu Song ◽  
Duckdong Hwang ◽  
...  
Keyword(s):  
Relay Selection ◽  
Antenna Selection ◽  
Diversity Gain ◽  
Spatial Density ◽  
Compound Channel ◽  
Selection Algorithm ◽  
Communication Performance ◽  
Selection Scheme ◽  
Fifth Generation ◽  
Data Throughput

As a cellular network of the fifth generation (5G) is commercialized, mobile devices and data throughput have rapidly increased. According to the spatial density for communication increases, the nodes of cell are overloaded. Therefore, the heterogeneous ultra dense network (UDN) is suggested. Furthermore, the techniques for selecting a relay have been proposed in the Heterogeneous Net (HetNet). The relays are needed to improve communication performance and mitigate overload of nodes. In this paper, an adaptive relay selection scheme is proposed to obtain the diversity gain from multiple relays. To enhance the reliability of communication, the proposed scheme suggests a new algorithm considering outage probability and diversity gain of compound channel. Furthermore, the selected relays use an antenna selection algorithm to improve the channel capacity. Simulation results show that the proposed scheme improves the bit error rate (BER) and the data throughput.

scholarly journals Wireless Energy Harvesting with Cooperative Relaying under the Best Relay Selection Scheme

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 892 ◽  
Author(s):  
Admoon Andrawes ◽  
Rosdiadee Nordin ◽  
Mahamod Ismail
Keyword(s):  
Energy Harvesting ◽  
Relay Selection ◽  
Cooperative Relaying ◽  
Selection Scheme ◽  
Fifth Generation ◽  
Best Relay Selection ◽  
Positive Gain ◽  
Energy Constrained ◽  
Optimum Solution ◽  
Wireless Energy Harvesting

One of the most notable challenges in wireless communications is energy scarcity, which has attracted considerable attention in Fifth Generation (5G) wireless network research. This paper investigates the performance of energy harvesting (EH) relays under the best relay selection (BRS) scheme. The results show degradation of spectral efficiency (SE) due to EH relaying compared with conventional cooperative relaying (CR). Conversely, EH relaying provides a positive gain compared with conventional CR, increasing the lifetime of the network and decreasing energy consumption (EC) and operational cost. Moreover, the EH relaying network has better energy efficiency (EE) compared with conventional relaying networks. Results show that when EH relaying is applied, EE is improved through an increased number of relays. Finally, the SE-EE metric is presented for both conventional and EH relays. Results show that the performance of the proposed technique was able to achieve a maximum SE of 1.4 bits/s/Hz and maximum EE at 0.6 bits/s/Hz, and for the case of conventional relays, a maximum SE of 2 bits/s/Hz and EE at 1.1 bits/s/Hz. This result implies that the proposed EH scheme provides an optimum solution for energy-constrained wireless CR systems.

Combined User and Antenna Selection in Massive MIMO Using Precoding Technique

2019 ◽  
Vol 9 (2) ◽  
pp. 214-223 ◽  
Author(s):  
Tasher Ali Sheikh ◽  
Joyatri Bora ◽  
Md. Anwar Hussain
Keyword(s):  
Massive Mimo ◽  
Antenna Selection ◽  
Orthogonality Condition ◽  
Channel Gain ◽  
User Selection ◽  
Selection Algorithm

Background and Objectives: We propose here joint semi-orthogonal user selection and antenna selection algorithm based on precoding scheme. Methods: The focus of this proposed algorithm is to increase the system sumrate and decrease the complexity. We select and schedule users from a large number of users based on semi-orthogonality condition among them. Here, we select only the maximum channel gain antennas to maximize the system sumrate. Subsequently, the user selection and antenna selection have been scheduled in an adequate manner in order to obtain maximum system sumrate. We calculate the system sumrate for two scenarios: firstly, by considering the interference and secondly without considering the interference. We achieve maximum system sumrate at MMSE and lowest at without precoding while considering the interference. However, when we do not consider the interference we obtain lowest sumrate at MMSE and maximum at without precoding. Results and Conclusion: Here, we apply the precoding scheme to increase the system sumrate and we obtain approximately 20% to 35% higher system sumrate compared to without precoding, when interference is considered. Thus, we achieve higher sumrate in our proposed algorithms compared to other existing work.

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 Buffer-Aided Successive Relay Selection Scheme for Energy Harvesting IoT Networks

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 36246-36258 ◽  
Author(s):  
Ghulam Shabbir ◽  
Jamil Ahmad ◽  
Waseem Raza ◽  
Yasar Amin ◽  
Adeel Akram ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Relay Selection ◽  
Selection Scheme

Secure AF relaying with efficient partial relay selection scheme

2019 ◽  
Vol 32 (15) ◽  
pp. e4105 ◽  
Author(s):  
Shao-I Chu ◽  
Bing-Hong Liu ◽  
Ngoc-Tu Nguyen
Keyword(s):  
Relay Selection ◽  
Selection Scheme ◽  
Partial Relay Selection ◽  
Af Relaying
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