scholarly journals On Throughput for UAV Relay Assisted for Use in Disaster Communications

2021 ◽  
Author(s):  
Van Vo Nhan ◽  
Dang Ngoc Cuong ◽  
Tran Ban Thach ◽  
Hung Tran
Keyword(s):  
System Performance ◽  
Multiple Access ◽  
Base Station ◽  
Closed Form Expression ◽  
Second Phase ◽  
Form Expression ◽  
Decode And Forward ◽  
Disaster Communications ◽  
Aerial Vehicle ◽  
Two Phases

In this paper, the system performance of an energy harvesting (EH) unmanned aerial vehicle (UAV) system for use in disasters was investigated. The communication protocol was divided into two phases. In the first phase, a UAV relay (UR) harvested energy from a power beacon (PB). In the second phase, a base station (BS) transmitted the signal to the UR using non-orthogonal multiple access (NOMA); then, the UR used its harvested energy from the first phase to transfer the signal to two sensor clusters, i.e., low-priority and high-priority clusters, via the decode-and-forward (DF) technique. A closed-form expression for the throughput of the cluster heads of these clusters was derived to analyze the system performance. Monte Carlo simulations were employed to verify our approach.

scholarly journals System Performance Analysis for an Energy Harvesting IoT System Using a DF/AF UAV-Enabled Relay with Downlink NOMA under Nakagami-m Fading

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 285
Author(s):  
Anh-Nhat Nguyen ◽  
Van Nhan Vo ◽  
Chakchai So-In ◽  
Dac-Binh Ha
Keyword(s):  
Energy Harvesting ◽  
System Performance ◽  
Base Station ◽  
Second Phase ◽  
Power Splitting ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Adaptive Power ◽  
Outage Probabilities ◽  
Two Phases

This paper investigates system performance in the Internet of Things (IoT) with an energy harvesting (EH) unmanned aerial vehicle (UAV)-enabled relay under Nakagami-m fading, where the time switching (TS) and adaptive power splitting (APS) protocols are applied for the UAV. Our proposed system model consists of a base station (BS), two IoT device (ID) clusters (i.e., a far cluster and a near cluster), and a multiantenna UAV-enabled relay (UR). We adopt a UR-aided TS and APS (U-TSAPS) protocol, in which the UR can dynamically optimize the respective power splitting ratio (PSR) according to the channel conditions. To improve the throughput, the nonorthogonal multiple access (NOMA) technique is applied in the transmission of both hops (i.e., from the BS to the UR and from the UR to the ID clusters). The U-TSAPS protocol is divided into two phases. In the first phase, the BS transmits a signal to the UR. The UR then splits the received signal into two streams for information processing and EH using the APS scheme. In the second phase, the selected antenna of the UR forwards the received signal to the best far ID (BFID) in the far cluster and the best near ID (BNID) in the near cluster using the decode-and-forward (DF) or amplify-and-forward (AF) NOMA scheme. We derive closed-form expressions for the outage probabilities (OPs) at the BFID and BNID with the APS ratio under imperfect channel state information (ICSI) to evaluate the system performance. Based on these derivations, the throughputs of the considered system are also evaluated. Moreover, we propose an algorithm for determining the nearly optimal EH time for the system to minimize the OP. In addition, Monte Carlo simulation results are presented to confirm the accuracy of our analysis based on simulations of the system performance under various system parameters, such as the EH time, the height and position of the UR, the number of UR antennas, and the number of IDs in each cluster.

scholarly journals System Performance of Cooperative NOMA with Full-Duplex Relay over Nakagami-m Fading Channels

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xuan-Xinh Nguyen ◽  
Dinh-Thuan Do
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Multiple Access ◽  
Base Station ◽  
Full Duplex ◽  
Decode And Forward ◽  
Relay Systems ◽  
Channel Environment ◽  
Analytical Expressions ◽  
Dual User

In this paper, we consider a dual-user nonorthogonal multiple access (NOMA) with the help of full-duplex decode-and-forward (DF) relay systems with respect to Nakagami-m fading channel environment. Especially, we derive the analytical expressions to evaluate system performance in terms of outage probability, achievable throughput, and energy efficiency. The main investigation is on considering how the fading parameters and transmitting power at the base station make crucial impacts on system performance in the various scenarios. Finally, simulations are conducted to confirm the validity of the analysis and show the system performance of NOMA under different fading parameters of Nakagami-m fading channels.

scholarly journals SWIPT in mMIMO system with non-linear energy-harvesting terminals: protocol design and performance optimization

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Kui Xu ◽  
Ming Zhang ◽  
Jie Liu ◽  
Nan Sha ◽  
Wei Xie ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Performance Optimization ◽  
Power Transmission ◽  
Base Station ◽  
Second Phase ◽  
Wireless Power ◽  
Half Duplex ◽  
Non Linear ◽  
Two Phases ◽  
And Performance

Abstract In this paper, we design the simultaneous wireless information and power transfer (SWIPT) protocol for massive multi-input multi-output (mMIMO) system with non-linear energy-harvesting (EH) terminals. In this system, the base station (BS) serves a set of uplink fixed half-duplex (HD) terminals with non-linear energy harvester. Considering the non-linearity of practical energy-harvesting circuits, we adopt the realistic non-linear EH model rather than the idealistic linear EH model. The proposed SWIPT protocol can be divided into two phases. The first phase is designed for terminals EH and downlink training. A beam domain energy beamforming method is employed for the wireless power transmission. In the second phase, the BS forms the two-layer receive beamformers for the reception of signals transmitted by terminals. In order to improve the spectral efficiency (SE) of the system, the BS transmit power- and time-switching ratios are optimized. Simulation results show the superiority of the proposed beam-domain SWIPT protocol on SE performance compared with the conventional mMIMO SWIPT protocols.

Outage Performance Analysis for User Cooperative NOMA with Incremental Hybrid Forwarding Protocols

2021 ◽  
Author(s):  
Suyue Li ◽  
Junhuai Liu ◽  
Anhong Wang
Keyword(s):  
Monte Carlo ◽  
Outage Probability ◽  
Multiple Access ◽  
System Throughput ◽  
Closed Form Expression ◽  
Collaborative Communication ◽  
Form Expression ◽  
Outage Performance ◽  
Threshold Rate ◽  
Rate Pair

Abstract Non-orthogonal multiple access (NOMA) collaborative communication is extremely beneficial to the users with poor channel conditions. It is essential to examine the performance of different NOMA users with superior cooperative forwarding protocols. This paper addresses the user cooperative NOMA system where one strong user (U2) assists one weak user (U1) to forward messages, and investigates the outage performance of both users with hybrid decode-and-amplify forwarding (HDAF) protocol. First, we derive the outage probability of U2 and U1 with HDAF. Secondly, we provide the closed-form expression for outage probability of U1 with the incremental hybrid decode-and-amplify forward (IHDAF) protocol at U2, which can further enhance the outage performance of U1 compared with HDAF. Moreover, we also present the system throughput expression and provide deep analysis on the effect of different forwarding protocols. Numerical results and Monte Carlo simulations jointly confirm the correctness of all the analytic derivations. In addition to saving the energy consumption of U2, IHDAF can make U1 achieve superior outage performance to HDAF. However, the system throughput almost overlap for both schemes given a threshold rate pair.

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 Trajectory Design for UAV-Based Data Collection Using Clustering Model in Smart Farming

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 37
Author(s):  
Tariq Qayyum ◽  
Zouheir Trabelsi ◽  
Asad Malik ◽  
Kadhim Hayawi
Keyword(s):  
Data Collection ◽  
Base Station ◽  
Second Phase ◽  
Trajectory Design ◽  
Delay Sensitive ◽  
Clustering Model ◽  
Proposed Model ◽  
Smart Farming ◽  
Two Phases ◽  
Collection Phase

Unmanned aerial vehicles (UAVs) play an important role in facilitating data collection in remote areas due to their remote mobility. The collected data require processing close to the end-user to support delay-sensitive applications. In this paper, we proposed a data collection scheme and scheduling framework for smart farms. We categorized the proposed model into two phases: data collection and data scheduling. In the data collection phase, the IoT sensors are deployed randomly to form a cluster based on their RSSI. The UAV calculates an optimum trajectory in order to gather data from all clusters. The UAV offloads the data to the nearest base station. In the second phase, the BS finds the optimally available fog node based on efficiency, response rate, and availability to send workload for processing. The proposed framework is implemented in OMNeT++ and compared with existing work in terms of energy and network delay.

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 Rate-Splitting Multiple Access for Intelligent Reflecting Surface aided Multi-User Communications

2021 ◽  
Author(s):  
Ankur Bansal ◽  
Keshav Singh ◽  
Bruno Clerckx ◽  
Chih-Peng Li ◽  
Mohamed-Slim Alouini
Keyword(s):  
Interference Cancellation ◽  
Multiple Access ◽  
Base Station ◽  
Control Technique ◽  
Decode And Forward ◽  
Cell Edge ◽  
Single Antenna ◽  
Rate Splitting ◽  
Reflecting Surface ◽  
The Impact

Intelligent reflecting surface (IRS) has recently emerged as a promising technology for 6G wireless systems, due to its capability to reconfigure the wireless propagation environment. In this paper, we investigate a Rate-Splitting Multiple Access (RSMA) for IRS-assisted downlink system, where the base station (BS) communicates with single-antenna users with the help of an IRS. RSMA relies on rate-splitting (RS) at the BS and successive interference cancellation (SIC) at the users and provides a generalized multiple access framework. We derive a new architecture called IRS-RS that leverages the interplay between RS and IRS. For performance analysis, we utilize an \textit{on-off control technique} to control the passive beamforming vector of the IRS-RS and derive the closed-form expressions for outage probability of cell-edge users and near users. Moreover, we also analyze the outage behavior of cell-edge users for a sufficiently large number of reflecting elements. Additionally, we also analyze the outage performance of cooperative RS based decode-and-forward (DF)-assisted framework called DF-RS. Through simulation results, it is shown that the proposed framework outperforms the corresponding DF-RS, RS without IRS and IRS-assisted conventional non-orthogonal multiple access (NOMA) schemes. Furthermore, the impact of various system's parameters such as the number of IRS reflecting elements and the number of users on the system performance is revealed.

scholarly journals Secrecy Performance Analysis of Hybrid RF/VLC Dual-Hop Relaying Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaoli Liu ◽  
Jinyuan Wang ◽  
Bingyuan Zhang ◽  
Qinglin Wang
Keyword(s):  
Closed Form ◽  
Path Loss ◽  
Relay Node ◽  
Visible Light Communication ◽  
Optical Signal ◽  
Electrical Signal ◽  
Closed Form Expression ◽  
Secrecy Outage Probability ◽  
Form Expression ◽  
Decode And Forward

In this article, the secrecy performance of a hybrid radio frequency (RF)/visible light communication (VLC) system is studied. In this hybrid system, the source node (i.e., Alice) transmits information to the relay node via the outdoor RF link. Nakagami-m fading and path loss are considered for the RF link. The relay node includes an outdoor component and an indoor component, which are connected by using a wired medium. The outdoor component receives and recovers information by using the decode-and-forward (DF) relaying scheme and then transmits it to the indoor component. The indoor component then converts the received electrical signal into an optical signal by using a light-emitting diode. A legitimate receiver (i.e., Bob) deployed on the floor receives the optical signal. An eavesdropper (i.e., Eve) deployed in the RF or VLC link wiretaps the confidential information. In this study, we use the secrecy outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) to evaluate the system performance. We then obtain the closed-form expression for a lower bound on the SOP and an exact closed-form expression for the probability of SPSC when the RF and VLC links are wiretapped, respectively. Numerical results are presented to validate the accuracy of our derivations. We further discuss the effects of the noise standard deviation, the equivalent threshold of the signal-to-noise ratio, and the floor radius on the system secrecy performance when the VLC link is eavesdropped upon. For the case when the RF link is eavesdropped upon, the impacts of the distance between Alice and the relay, the path loss exponent, the fading factor, and the distance between Alice and Eve on secrecy performance are also provided.

Exact Ergodic Capacity Analysis for Cognitive Underlay Amplify-and-Forward Relay Networks over Rayleigh Fading Channels

2017 ◽  
Author(s):  
Vo Nguyen Quoc Bao ◽  
Vu Van San
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Relay Networks ◽  
Ergodic Capacity ◽  
Closed Form Expression ◽  
Rayleigh Fading Channels ◽  
Capacity Analysis ◽  
Amplify And Forward ◽  
Form Expression ◽  
Decode And Forward

In this paper, we propose a novel derivation approach to obtain the exact closed form expression of ergodic capacity for cognitive underlay amplify-and-forward (AF) relay networks over Rayleigh fading channels. Simulation results are performed to verify the analysis results. Numerical results are provided to compare the system performance of cognitive underlay amplify-and-forward relay networks under both cases of AF and decode-and-forward (DF) confirming that the system with DF provides better performance as compared with that with AF. DOI: 10.32913/rd-ict.vol3.no14.563

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