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A Novel Beamforming Emulating Photonic Nanojets for Wireless Relay Networks 被引量:3
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作者 Samer Alabed Ibrahim Mahariq +1 位作者 Mohammad Salman Mustafa Kuzuoglu 《Computers, Materials & Continua》 SCIE EI 2021年第10期575-588,共14页
In this article,a low-cost electromagnetic structure emulating photonic nanojets is utilized to improve the efficiency of wireless relay networks.The spectral element method,due to its high accuracy,is used to verify ... In this article,a low-cost electromagnetic structure emulating photonic nanojets is utilized to improve the efficiency of wireless relay networks.The spectral element method,due to its high accuracy,is used to verify the efficiency of the proposed structure by solving the associate field distribution.The application of optimal single-relay selection method shows that full diversity gain with low complexity can be achieved.In this paper,the proposed technique using smart relays combines the aforementioned two methods to attain the benefits of both methods by achieving the highest coding and diversity gain and enhances the overall network performance in terms of bit error rate(BER).Moreover,we analytically prove the advantage of using the proposed technique.In our simulations,it can be shown that the proposed technique outperforms the best known state-of-the-art single relay selection technique.Furthermore,the BER expressions obtained from the theoretical analysis are perfectly matched to those obtained from the conducted simulations. 展开更多
关键词 wireless relay networks cooperative diversity techniques relay selection network beamforming techniques
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Two-Phase Bidirectional Dual-Relay Selection Strategy for Wireless Relay Networks 被引量:1
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作者 Samer Alabed Issam Maaz Mohammad Al-Rabayah 《Computers, Materials & Continua》 SCIE EI 2021年第10期539-553,共15页
In this article,we introduce a new bi-directional dual-relay selection strategy with its bit error rate(BER)performance analysis.During the first step of the proposed strategy,two relays out of a set of N relay-nodes ... In this article,we introduce a new bi-directional dual-relay selection strategy with its bit error rate(BER)performance analysis.During the first step of the proposed strategy,two relays out of a set of N relay-nodes are selected in a way to optimize the system performance in terms of BER,based on the suggested algorithm which checks if the selected relays using the maxmin criterion are the best ones.In the second step,the chosen relay-nodes perform an orthogonal space-time coding scheme using the two-phase relaying protocol to establish a bi-directional communication between the communicating terminals,leading to a significant improvement in the achievable coding and diversity gain.To further improve the overall system performance,the selected relay-nodes apply also a digital network coding scheme.Furthermore,this paper discusses the analytical approximation of the BER performance of the proposed strategy,where we prove that the analytical results match almost perfectly the simulated ones.Finally,our simulation results show that the proposed strategy outperforms the current state-of-the-art ones. 展开更多
关键词 Two-way wireless relay networks cooperative diversity techniques distributed space-time coding relay selection strategies network coding schemes
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A Beamforming Technique Using Rotman Lens Antenna for Wireless Relay Networks
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作者 Samer Alabed Mohammad Al-Rabayah Wael Hosny Fouad Aly 《Computers, Materials & Continua》 SCIE EI 2022年第12期5641-5653,共13页
Rotman lens,which is a radio frequency beam-former that consists of multiple input and multiple output beam ports,can be used in industrial,scientific,and medical applications as a beam steering device.The input ports... Rotman lens,which is a radio frequency beam-former that consists of multiple input and multiple output beam ports,can be used in industrial,scientific,and medical applications as a beam steering device.The input ports collect the signals to be propagated through the lens cavity toward the output ports before being transmitted by the antenna arrays to the destination in order to enhance the error performance by optimizing the overall signal to noise ratio(SNR).In this article,a low-cost Rotman lens antenna is designed and deployed to enhance the overall performance of the conventional cooperative communication systems without needing any additional power,extra time or frequency slots.In the suggested system,the smart Rotman lens antennas generate a beam steering in the direction of the destination to maximize the received SNR at the destination by applying the proposed optimal beamforming technique.The suggested optimal beamforming technique enjoys high diversity,as well as,low encoding and decoding complexity.Furthermore,we proved the advantages of our suggested strategy through both theoretical results and simulations using Monte Carlo runs.The Monte Carlo simulations show that the suggested strategy enjoys better error performance compared to the current state-of-the-art distributed multiantenna strategies.In addition,the bit error rate(BER)curves drawn from the analytical results are closely matching to those drawn from our conducted Monte Carlo simulations. 展开更多
关键词 Performance analysis smart antenna Rotman lens antenna multiantenna systems wireless relay networks cooperative diversity schemes digital network coding relay selection schemes
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Optimization of beamforming and path planning for UAV-assisted wireless relay networks 被引量:14
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作者 Ouyang Jian Zhuang Yi +1 位作者 Lin Min Liu Jia 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2014年第2期313-320,共8页
Recently, unmanned aerial vehicles (UAVs) acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifi... Recently, unmanned aerial vehicles (UAVs) acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifically, in the scenario where the access point (AP) is mobile, a UAV needs to find an efficient path to guarantee the connectivity of the relay link. Motivated by this fact, this paper proposes an optimal design for beamforming (BF) and UAV path planning. First of all, we study a dual-hop amplify-and-forward (AF) wireless relay network, in which a UAV is used as relay between a mobile AP and a fixed base station (BS). In the network, both of the AP and the BS are equipped with multiple antennas, whereas the UAV has a single antenna. Then, we obtain the output signal^to-noise ratio (SNR) of the dual-hop relay network. Based on the criterion of maximizing the output SNR, we develop an optimal design to obtain the solution of the optimal BF weight vector and the UAV heading angle. Next, we derive the closed-form outage probability (OP) expression to investigate the performance of the dual-hop relay network conveniently. Finally, computer simulations show that the proposed approach can obtain nearly optimal flying path and OP performance, indicating the effectiveness of the proposed algorithm. Furthermore, we find that increasing the antenna number at the BS or the maximal heading angle can significantly improve the performance of the considered relay network. 展开更多
关键词 Aircraft communication Beam forming Path planning Unmanned aerial vehicles wireless relay networks
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Resource allocation using time division multiple access over wireless relay networks
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作者 DAI Qin-yun RONG Lu +1 位作者 HU Hong-lin SU Gang 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2008年第3期69-74,共6页
This article considers a wireless network consisting of multiple sources that communicate with the corresponding destination utilizing a single half-duplex relay, whereas, the sources use the relay opportunistically. ... This article considers a wireless network consisting of multiple sources that communicate with the corresponding destination utilizing a single half-duplex relay, whereas, the sources use the relay opportunistically. By integrating the information theory with the concept of effective capacity, this article proposes a dynamic time allocation strategy over the wireless relay network that aims at maximizing the relay network throughput, subject to a given delay quality of service (QoS) constraint, where time division multiple access (TDMA) is applied in the relay network. The simulation results show that the proposed allocation strategy can significantly improve the effective capacity as compared to the traditional equal time allocation strategy. 展开更多
关键词 resource allocation wireless relay networks effective capacity opportunistic transmission cooperative diversity
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Wireless Mesh Networks and Cooperative Relaying Technologies 被引量:2
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作者 Jiang Xiaokui (Wireless Pre- research Department of ZTE Corporation, Xi’an 710065, China ) 《ZTE Communications》 2008年第2期20-24,共5页
The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it ca... The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it cannot be applied in situations where large coverage is required . The use of cooperative relaying technologies can improve the transmission rate and reliability of wireless link; while the wireless Mesh network, once integrated with cooperative relaying technologies and routing technologies , can improve its spectrum efficiency and cover a wide area . However, there are many problems to be solved with respect to standardization, key technologies research and industrialization. Therefore , the application of cooperative relaying technologies in wireless Mesh networks is still a great challenge . 展开更多
关键词 MESH wireless Mesh Networks and Cooperative relaying Technologies WMN
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Full Duplex Media Access Control Protocol for Multihop Network Computing
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作者 J.Avila Selvi Therase S.Allwin A.Ahilan 《Computer Systems Science & Engineering》 SCIE EI 2023年第1期297-309,共13页
Intelligent communication technologies beyond the network are pro-posed by using a new full-duplex protocol.The Media Access Control(MAC)is a data interaction network protocol,which outperforms the IEEE 802.15.4e.This... Intelligent communication technologies beyond the network are pro-posed by using a new full-duplex protocol.The Media Access Control(MAC)is a data interaction network protocol,which outperforms the IEEE 802.15.4e.This research discusses the planning and execution of full-duplex(FD)pipeline MAC protocol for multihop wireless networks(MWN).The design uses a com-bination of Radio frequency and baseband methods to realize full-duplexing with smallest impact on cross layer functions.The execution and trial results specify that Pipeline Media Access Control(PiMAC)protocol considerably develops net-work implementation in terms of transmission protocol(TP)and transmission delay.The advantage of using FD-MAC will increase the range of nodes.Also takes benefit of the FD mode of the antenna,which outperforms additionally 80%for all assessed cases.In this analysis,it was considered of that Psz=8184 bits and Rc=1Mbps;that’s,T_(DATA) represents an excellent portion of total UTC.Tests on real nodes displays that the FD theme achieves a median gain of 90%in mix-ture throughput as equated to half-duplex(HD)theme for MWN.The energy con-sumption of proposed system method is 29.8%reduced when compared with existing system method. 展开更多
关键词 Beyondfifth-generation(B5G) FD MAC wi-finetworks wireless relay network multihop wireless networks
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Centralized and distributed resource allocation in OFDM based multi-relay system 被引量:2
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作者 Rui YIN Yu ZHANG +2 位作者 Guan-ding YU Zhao-yang ZHANG Jie-tao ZHANG 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2010年第6期450-464,共15页
In the presence of multiple non-regenerative relays, we derived optimal joint power allocation, relay selection, and subchannel pairing schemes in orthogonal frequency division multiplexing(OFDM) based wireless networ... In the presence of multiple non-regenerative relays, we derived optimal joint power allocation, relay selection, and subchannel pairing schemes in orthogonal frequency division multiplexing(OFDM) based wireless networks.The Lagrange dual method was employed to design the optimal algorithm.First, the optimization problem was formulated for the single-relay system and the optimal centralized algorithm was presented by resolving the dual problem.Next, the optimal algorithm for a multi-relay system was proposed in a similar way.Compared with the exhaustive search method, the computational complexity of the proposed optimal algorithms was reduced from non-polynomial to polynomial time.Finally, the centralized algorithm was extended to the distributed algorithm, which was more feasible for the practical system.Simulation results verify our analysis. 展开更多
关键词 wireless relay network Orthogonal frequency division multiplexing(OFDM) relay selection Convex optimization Dual method
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