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Multiobjective distributed beamforming Using High-Accuracy Synchronization and Localization

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2025年第4期73卷 2404-2413页

作者： Bhattacharyya, Ahona Nanzer, Jeffrey A. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48824 USA

We present a multinode, multiobjective open-loop microwave distributed beamforming system based on high-accuracy wireless synchronization and localization. distributed beamforming requires accurate coordination of the spatial and electrical states of the individual elements within the array to achieve and maintain coherent beamforming at intended destinations. Of the basic coordination aspects, time synchronization and localization of the elements are among the most critical to support beamforming of modulated waveforms to destinations in both the near-field and far-field relative to the array. In this work, we demonstrate multiobjective distributed beamforming from a three-node software-defined radio distributed phased array system that leverages high-accuracy wireless time coordination for both time synchronization and 2-D localization of the elements. We use a spectrally sparse two-tone waveform for high-accuracy internode range estimation combined with a linear frequency-modulated waveform to mitigate multipath interference. Localization is performed in a centralized format, where one node is designated as the origin and the remaining nodes build the array geometry relative to the origin, from which we obtain localization accuracy of less than 1. We implement a near-field multiobjective beamformer based on the location estimates, which enables simultaneous steering of a beam and a null to two receiving antennas. Multiobjective beamforming of pulsed waveforms at a carrier frequency of 2.1GHz is demonstrated in cases where one of the nodes in the distributed antenna array is moved, and where the targets (the two receiving antennas) are moved, demonstrating multiobjective with steerable beamforming and displacement of the array elements.

关键词： Synchronization Array signal processing Location awareness Accuracy Phased arrays Clocks Wireless communication Propagation delay Wireless sensor networks Estimation distributed beamforming distributed phased arrays localization multiobjective beamforming near-field beamforming synchronization

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distributed beamforming Based Wireless Power Transfer:Analysis and Realization

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Tsinghua Science and Technology 2020年第6期25卷 758-775页

作者： Xiaoran Fan Han Ding Yanyong Zhang Wade Trappe Zhu Han Rich Howard the Wireless Information Network Laboratory(WINLAB) Rutgers UniversityNew BrunswickNJ 08901USA the Department of Computer Science and Technology Xi'an Jiaotong UniversityXi'an 710049China the Department of Computer Science and Technology University of Science and Technology of ChinaHefei 230052China the Department of Electrical and Computer Engineering University of HoustonHoustonTX 77004USA.

This paper presents a new Wireless Power Transfer(WPT)approach by aligning the phases of a group of spatially distributed Radio Frequency(RF)transmitters(TX)at the target receiver(RX)*** approach can transfer energy over tens of meters and even to targets blocked by *** to popular beamforming based WPTs,our approach leads to a drastically different energy density distribution:the energy density at the target receiver is much higher than the energy density at other *** to this unique energy distribution pattern,our approach offers a safer WPT solution,which can be potentially scaled up to ship a higher level of energy over longer ***,we model the energy density distribution and prove that our proposed system can create a high energy peak exactly at the target *** we conduct detailed simulation studies to investigate how the actual energy distribution is impacted by various important system parameters,including number/topology of transmitters,transmitter antenna directionality,the distance between receiver and transmitters,and environmental ***,we build an actual prototype with 17 N210 and 4 B210 Universal Software Radio Peripheral(USRP)nodes,through which we validate the salient features and performance promises of the proposed system.

关键词： Wireless Power Transfer(WPT) distributed beamforming wireless network

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distributed beamforming in Dynamic TDD MIMO Networks With BS to BS Interference Constraints

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IEEE WIRELESS COMMUNICATIONS LETTERS 2018年第5期7卷 788-791页

作者： Cavalcante, Eduardo de Olivindo Fodor, Gabor Silva, Yuri C. B. Freitas Jr, Walter C. Univ Fed Ceara Wireless Telecom Res Grp BR-60020181 Fortaleza Ceara Brazil Ericsson Res SE-16480 Stockholm Sweden Royal Inst Technol Dept Automat Control SE-10044 Stockholm Sweden

This letter proposes distributed beamforming as a means of reducing interference in dynamic time division duplexing multiple input multiple output networks. Specifically, we formulate an optimization task, whose objective is to minimize the base station (BS) transmit power, while satisfying a predefined signal-to-interference-plus-noise ratio threshold for each downlink user equipment and keeping the BS to BS interference power below a tolerable level. An iterative decentralized solution requiring reduced signaling load based on primal decomposition is proposed. This decentralized algorithm is shown to iterate towards the centralized solution, while feasible but suboptimal solutions can be obtained at any iteration.

关键词： distributed beamforming dynamic TDD interference sum-power minimization

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distributed beamforming for relay networks based on second-order statistics of the channel state information

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2008年第9期56卷 4306-4316页

作者： Havary-Nassab, Veria Shahbazpanahi, Shahram Grami, Ali Luo, Zhi-Quan Univ Ontario Inst Technol Fac Engn & Appl Sci Oshawa ON L1H 7K4 Canada Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

In this paper, the problem of distributed beam-forming is considered for a wireless network which consists of a transmitter, a receiver, and r relay nodes. For such a network, assuming that the second-order statistics of the channel coefficients are available, we study two different beamforming design approaches. As the first approach, we design the beamformer through minimization of the total transmit power subject to the receiver quality of service constraint. We show that this approach yields a closed-form solution. In the second approach, the beamforming weights are obtained through maximizing the receiver signal-to-noise ratio (SNR) subject to two different types of power constraints, namely the total transmit power constraint and individual relay power constraints. We show that the total power constraint leads to a closed-form solution while the individual relay power constraints result in a quadratic programming optimization problem. The later optimization problem does not have a closed-form solution. However, it is shown that using semidefinite relaxation, this problem can be turned into a convex feasibility semidefinite programming (SDP), and therefore, can be efficiently solved using interior point methods. Furthermore, we develop a simplified, thus suboptimal, technique which is computationally more efficient than the SDP approach. In fact, the simplified algorithm provides the beamforming weight vector in a closed form. Our numerical examples show that as the uncertainty in the channel state information is increased, satisfying the quality of service constraint becomes harder, i.e., it takes more power to satisfy these constraints. Also our simulation results show that when compared to the SDP-based method, our simplified technique suffers a 2-dB loss in SNR for low to moderate values of transmit power.

关键词： convex feasibility problem distributed beamforming distributed signal processing relay networks semidefinite programming

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distributed beamforming and power allocation for cooperative networks

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2008年第5期7卷 1817-1822页

作者： Ding, Zhiguo Chin, Woon Hau Leung, Kin K. Univ Lancaster Dept Commun Syst Lancaster LA1 4WA England Inst Infocomm Res Singapore 119613 Singapore Univ London Imperial Coll Sci Technol & Med Dept Elect Engn London SW7 2BT England

Cooperative diversity systems rely on using relay nodes to relay copies of transmitted information to the destination such that each copy experiences different channel fading, hence increasing the diversity of the system. However, without proper processing of the message at the relays, the performance of the cooperative system may not necessarily perform better than direct transmission systems. In this paper, we proposed a distributed beamforming and power allocation algorithm which substantially improves the diversity of the system with only very limited feedback from the destination node. We also derive outage probability as well as study the outage behavior of this scheme.

关键词： cooperative networks distributed beamforming cooperative diversity outage probability

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distributed beamforming for Energy-Harvesting Relaying in Vehicular Networks

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Journal of Communications and Information Networks 2020年第2期5卷 160-167页

作者： Yuxiang Liang Bing Li Rongqing Zhang Hongze Li Shengjie Zhao School of Software Engineering Tongji UniversityShanghai 201804China School of Electronics and Information Engineering Tongji UniversityShanghai 201804China

Recently,battery capacity and charging speed have been the bottlenecks of mobile communication *** harvesting(EH)relaying has become a promising solution for green 5th generation mobile communication with the advancement of wireless power transfer *** this paper,we investigate EH relaying in vehicular networks and adopt distributed beamforming(DB)to enhance the reliability and capacity of EH *** be more specific,we propose a DB solution based on the joint optimization of power-splitting(PS)*** amplify-and-forward relaying,to transform the optimization problem into a quasi-convex one,we apply the semidefinite relaxation(SDR)method so that we can effectively attain the global optimal solution,while the suboptimal DB solution with distributed optimal PS factor which only requires local channel state information is also *** decode-and-forward relaying,to get the optimal PS factors,we set a signal-to-noise ratio threshold at the relays,which can reduce the system error rate caused by the poor transmission *** results demonstrate the efficiency of our proposed DB-based EH relaying scheme in vehicular networks.

关键词： vehicular networks energy-harvesting relay SWIPT power splitting distributed beamforming

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distributed beamforming in the Presence of Adversaries

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2020年第9期69卷 9682-9696页

作者： Kong, Justin Dagefu, Fikadu T. Sadler, Brian M. US Army Res Lab Adelphi MD 20783 USA

In this article, we investigate the problem of distributed coherent beamforming in wireless networks where multiple distributed transmitters adjust the phases of their signals to form a directional and targeted communication link to a client receiver. The quality-of-service (QoS) and security are key components of robust and secure wireless networks. Although the security can be improved by exploiting information about potential adversaries, such information may not be available in practical networks since the adversaries are often passive. Therefore, we introduce transmission strategies which not only send a confidential message by forming a beam towards the client but also broadcast interference with the aim of obfuscating adversaries without having any information about them. Since the interference may degrade the QoS of the client, the transmitters radiating the interference steer a null to the client to alleviate the interference. We develop two algorithms. The first assumes that a subset of the transmitters send the confidential message in the direction of the client via coherent beamforming. Then, the others transmit interference while creating a null towards the client. In the second, each node transmits both the confidential message and interference simultaneously. Two different client feedback scenarios are considered, two-bit and rich feedback. Both of the proposed algorithms can be performed in a fully distributed manner without any knowledge about potential adversaries. Numerical simulations in both microwave and low-very high frequency (low-VHF) bands validate the effectiveness of the proposed schemes.

关键词： Transmitters Array signal processing Receivers Interference Quality of service Security Microwave communication distributed beamforming nullforming artificial noise physical layer security feedback communication

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distributed beamforming for Two-Way DF Relay Cognitive Networks Under Primary-Secondary Mutual Interference

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2015年第9期64卷 3918-3930页

作者： Afana, Ali Ghrayeb, Ali Asghari, Vahid Reza Affes, Sofiene Concordia Univ Montreal PQ H4B 1R6 Canada Texas A&M Univ Dept Elect & Comp Engn Doha 23874 Qatar Univ Quebec Inst Natl Rech Sci Montreal PQ G1K 9A9 Canada

In this paper, we consider collaborative beamforming for a cooperative two-way relay spectrum-sharing system where a pair of secondary transceivers communicates via a set of secondary decode-and-forward (DF) relays in the presence of multiple primary transceivers. Among the available relays, only those that receive the signals reliably participate in the cooperative beamforming process and use network coding to simultaneously transmit the weighted signals to the transceivers. Two practical two-way relaying strategies are investigated, namely, DF-XORing and DF-superposition. The former is based on bitwise-level XORing of the detected signals at the relays, whereas the latter is based on symbolwise-level addition at the relays. For each relaying strategy, we derive general optimal beamforming vectors at the relays to keep the interference inflicted on the primary receivers to a predefined threshold. Employing zero-forcing beamforming as a special case, we present an analytical framework of the performance of the secondary system considering the effect of the primary-secondary mutual cochannel interference (CCI). In particular, we derive closed-form expressions for the outage probability, bit error rate (BER), and achievable sum rates over independent and identically distributed Rayleigh fading channels. Numerical results demonstrate the effectiveness of beamforming in compensating for the cognitive system performance loss due to CCI in addition to mitigating the interference to the primary receivers. Simulation results also show that, when the received signals at the relays are equally weighted, DF-XOR always outperforms both DF-superposition and amplify-and-forward (AF) relaying.

关键词： Cognitive radio (CR) distributed beamforming performance analysis spectrum-sharing systems two-way relaying

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distributed beamforming for Wireless Sensor Networks With Improved Graph Connectivity and Energy Efficiency

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第3期58卷 1904-1921页

作者： Zarifi, Keyvan Ghrayeb, Ali Affes, Sofiene Univ Quebec INRS EMT Montreal PQ H5A 1K6 Canada Concordia Univ Montreal PQ H5A 1K6 Canada Concordia Univ Dept Elect & Comp Engn Montreal PQ H3G 1M8 Canada

As the nodes in wireless sensor networks (WSNs) are independent units, an intensive communication among them is required to generate a common signal and synchronize before entering a distributed beamforming (DBF) phase. Therefore, it is crucial to select the participating nodes in DBF such that not only the resulting beampattern meets the beamforming design requirements but also the internode connectivity is retained. We consider a DBF technique for WSNs with uniformly distributed nodes and derive an average beampattern expression for a general scenario wherein the participating nodes in DBF are located on a ring with arbitrary inner and outer radii. It is proved that increasing the ring inner radius from zero to a value close to the ring outer radius, the width of the average beampattern mainlobe continuously decreases. Further, it is shown that selecting the nodes from a neighborhood close to a disc perimeter, that is, choosing the nodes from the narrow ring adjacent to the inner side of the disc boundary, facilitates a substantial decrease in the network energy waste and the node isolation probability compared to the case that the nodes are randomly selected from the whole disc. A simple approximate expression for the average beampattern is obtained in the case where the nodes are selected from a narrow ring and is used to derive the sidelobes' null and peak positions as well as a tight lower bound on the average beampattern directivity. The proposed technique is then extended to the case where the nodes are located on multiple concentric rings and the set of rings' radii are derived that guarantee an average beampattern null at a required position while substantially decreasing the sidelobe peak levels compared to the single-ring case. Finally, an average beampattern expression is obtained in the case that the nodes' signals are contaminated by noise to show that most properties of the average beampattern in the noise-free signal case carry over to the noisy sig

关键词： Beampattern distributed beamforming energy efficiency network connectivity wireless sensor network

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distributed beamforming for Physical-Layer Security of Two-Way Relay Networks

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2012年第7期60卷 3532-3545页

作者： Wang, Hui-Ming Yin, Qinye Xia, Xiang-Gen Xi An Jiao Tong Univ Sch Elect & Informat Engn Minist Educ Key Lab Intelligent Networks & Network Secur Xian 710049 Peoples R China Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA Chonbuk Natl Univ Jeonju South Korea

In this paper, we address the security of a two-way relay network in the presence of an eavesdropper, where each node is only equipped with single antenna. We propose two-phase distributed analog network coding, or distributed beamforming and power allocation to enhance the secrecy sum rate of the data exchange. In the first phase, the two terminals broadcast their information data simultaneously to all the relay nodes. In the second phase, three different security schemes are proposed: optimal beamforming, null-space beamforming, and artificial noise beamforming. In the first scheme, the objective is to achieve the maximum secrecy sum rate of the two terminals. Mathematically, the objective function is difficult to optimize. In the second scheme, we maximize the total information exchanged while we eliminate the information leakage completely, subject to the total transmission power constraint. We show that the problem has a unique and global optimum, which can be solved using bisection method. When the instantaneous channel state information of the eavesdropper is not available, we propose an artificial noise beamforming in the third scheme. We minimize the information transmission power so that the artificial noise power is maximized to eliminate information leakage, under the constraints of quality of service (QoS) required by terminals. It is a second-order convex cone programming (SOCP) problem, thus can be efficiently solved using interior point methods. Numerical results are provided and analyzed to show the properties and efficiency of the proposed designs.

关键词： Analog network coding distributed beamforming physical layer security second-order cone programming secrecy rate two-way relay networks

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