Average Transmission Rate and Outage Performance of Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Thang V. Nguyen ◽  
Hoang D. Le ◽  
Ngoc T. Dang ◽  
Anh T. Pham
Keyword(s):  
Transmission Rate ◽  
Outage Performance ◽  
Rf Systems ◽  
Average Transmission

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

scholarly journals Average Transmission Rate and Outage Performance of Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Thang Nguyen
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Free Space ◽  
System Performance ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission

<div> <div> <div> <p>This paper proposes a rate adaptation design for high altitude platform (HAP)-aided relaying satellite hybrid free-space optical/radio-frequency (FSO/RF) systems. The design allows switching between two links gradually to reduce the fre- quent link switching in error-prone environments of conventional fixed-rate hybrid FSO/RF systems. System performance metrics, including average transmission rate and outage probability, are analytically studied under the presence of clouds and fading of FSO and RF channels modeled respectively by Gamma-Gamma and Rician distributions. The numerical results quantitatively highlight the effectiveness of our proposed systems over the conventional ones. Moreover, Monte-Carlo simulations are also performed to validate the accuracy of the analytical model. </p> </div> </div> </div>

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

scholarly journals Average Transmission Rate and Outage Performance of Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Thang Nguyen
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Free Space ◽  
System Performance ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission

<div> <div> <div> <p>This paper proposes a rate adaptation design for high altitude platform (HAP)-aided relaying satellite hybrid free-space optical/radio-frequency (FSO/RF) systems. The design allows switching between two links gradually to reduce the fre- quent link switching in error-prone environments of conventional fixed-rate hybrid FSO/RF systems. System performance metrics, including average transmission rate and outage probability, are analytically studied under the presence of clouds and fading of FSO and RF channels modeled respectively by Gamma-Gamma and Rician distributions. The numerical results quantitatively highlight the effectiveness of our proposed systems over the conventional ones. Moreover, Monte-Carlo simulations are also performed to validate the accuracy of the analytical model. </p> </div> </div> </div>

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

An Effective Congestion Control Algorithm based on Traffic Assignment and Reassignment in Wireless Sensor Network

2020 ◽  
Vol 13 (8) ◽  
pp. 1166-1174
Author(s):  
Chao Wang
Keyword(s):  
Wireless Sensor Network ◽  
Congestion Control ◽  
Sensor Network ◽  
Traffic Assignment ◽  
Transmission Rate ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Congestion Detection ◽  
Detection Technology ◽  
Average Transmission

Background: It is important to improve the quality of service by using congestion detection technology to find the potential congestion as early as possible in wireless sensor network. Methods: So an improved congestion control scheme based on traffic assignment and reassignment algorithm is proposed for congestion avoidance, detection and mitigation. The congestion area of the network is detected by predicting and setting threshold. When the congestion occurs, sensor nodes can be recovery quickly from congestion by adopting reasonable method of traffic reassignment. And the method can ensure the data in the congestion areas can be transferred to noncongestion areas as soon as possible. Results: The simulation results indicate that the proposed scheme can reduce the number of loss packets, improve the throughput, stabilize the average transmission rate of source node and reduce the end-to-end delay. Conclusion: : So the proposed scheme can enhance the overall performance of the network. Keywords: wireless sensor network; congestion control; congestion detection; congestion mitigation; traffic assignment; traffic reassignment.

scholarly journals Performance Optimization of Hybrid Satellite-Terrestrial Relay Network Based on CR-NOMA

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5177
Author(s):  
Long Zhao ◽  
Tao Liang ◽  
Kang An
Keyword(s):  
Performance Optimization ◽  
Transmission Rate ◽  
Relay Network ◽  
High Signal ◽  
Decode And Forward ◽  
Obvious Effect ◽  
Selection Scheme ◽  
Outage Performance ◽  
Multiple User ◽  
Power Domain

The non-orthogonal multiple access (NOMA) scheme realizes the transmission of multiple user signals at the same time and frequency resource block through power domain multiplexing, which improves the system transmission rate and user fairness. In this paper, we propose a joint relay-and-antenna selection scheme based on the cognitive radio scenario. This scheme can achieve the maximum communication rate of the secondary user when the primary user maintains the optimal outage performance. In the considered system both terrestrial relays and users are deployed with multi-antenna configurations and the terrestrial relays adopt the decode-and-forward (DF) strategy to achieve communication between satellites and users. Then, we derive the exact outage probability expression of each user in the system and the asymptotic probability expression under high signal-to-noise ratio (SNR). Numeric results demonstrate that increasing the number of relays and antennas on the terrestrial nodes can both improve system outage performance. Moreover, the number of relays imposes a more obvious effect on the achievable system performance.

scholarly journals Changing sex for selfish gain: B chromosomes of Lake Malawi cichlid fish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Frances E. Clark ◽  
Thomas D. Kocher
Keyword(s):  
Linkage Group ◽  
Transmission Rate ◽  
Cichlid Fish ◽  
Meiotic Drive ◽  
B Chromosome ◽  
Lake Malawi ◽  
B Chromosomes ◽  
Normal Complement ◽  
Biased Sex Ratio ◽  
Average Transmission

AbstractB chromosomes are extra, non-essential chromosomes present in addition to the normal complement of A chromosomes. Many species of cichlid fish in Lake Malawi carry a haploid, female-restricted B chromosome. Here we show that this B chromosome exhibits drive, with an average transmission rate of 70%. The offspring of B-transmitting females exhibit a strongly female-biased sex ratio. Genotyping of these offspring reveals the B chromosome carries a female sex determiner that is epistatically dominant to an XY system on linkage group 7. We suggest that this sex determiner evolved to enhance the meiotic drive of the B chromosome. This is some of the first evidence that female meiotic drive can lead to the invasion of new sex chromosomes solely to benefit the driver, and not to compensate for skewed sex ratios.

scholarly journals Outage Performance Analysis of Non-Orthogonal Multiple Access with Time-Switching Energy Harvesting

2019 ◽  
Vol 25 (3) ◽  
pp. 85-91
Author(s):  
Hoang Thien Van ◽  
Hoang-Sy Nguyen ◽  
Thanh-Sang Nguyen ◽  
Van Van Huynh ◽  
Thanh-Long Nguyen ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Communication Networks ◽  
Multiple Access ◽  
Transmission Rate ◽  
Wireless Communication Networks ◽  
Decode And Forward ◽  
Time Switching ◽  
Outage Performance ◽  
Half Duplex ◽  
The Given

In recent years, although non-orthogonal multiple access (NOMA) has shown its potentials thanks to its ability to enhance the performance of future wireless communication networks, a number of issues emerge related to the improvement of NOMA systems. In this work, we consider a half-duplex (HD) relaying cooperative NOMA network using decode-and-forward (DF) transmission mode with energy harvesting (EH) capacity, where we assume the NOMA destination (D) is able to receive two data symbols in two continuous time slots which leads to the higher transmission rate than traditional relaying networks. To analyse EH, we deploy time-switching (TS) architecture to comprehensively study the optimal transmission time and outage performance at D. In particular, we are going to obtain closed-form expressions for outage probability (OP) with optimal TS ratio for both data symbols with both exact and approximate forms. The given simulation results show that the placement of the relay (R) plays an important role in the system performance.

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