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    Robust and rapid converging adaptive beamforming via a subspace method for the signal-plusinterferences covariance matrix estimation

    , Article IET Signal Processing ; Vol. 8, Issue. 5 , July , 2014 , pp. 507-520 ; ISSN: 17519675 Rahmani, M ; Bastani, M. H ; Sharif University of Technology
    Abstract
    The presence of the desired signal (DS) in the training snapshots makes the adaptive beamformer sensitive to any steering vector mismatch and dramatically reduces the convergence rate. Even the performance of the most of the existing robust adaptive beamformers is degraded when the signal-to-noise ratio (SNR) is increased. In this study, a high converging rate robust adaptive beamformer is proposed. This method is a promoted eigenspace-based beamformer. In this paper, a new signal-plus-interferences (SPI) covariance matrix estimator is proposed. The subspace of the ideal SPI covariance matrices is exploited and the estimated covariance matrix is projected into this subspace. This projection... 

    Phased array radar beamforming method based on MIMO radar covariance

    , Article IET Conference Publications ; Volume 2013, Issue 617 CP , 2013 ; 9781849196031 (ISBN) Roshanzamir, A. S ; Bastani, M. H ; Sharif University of Technology
    2013
    Abstract
    A multiple input multiple output (MIMO) radar is an emerging field which has attracted many researchers recently. In this type of radar, unlike an standard phased array radar, one can choose transmitted probing signals freely to maximize the power around the locations of the targets of interest, or more generally to approximate a given transmit beam-pattern, or to minimize the cross-correlation of the signals reflected back to the radar by the targets of interest. These signals can be correlated to each other or noncorrelated. Many papers have investigated beampattern design and waveforming in MIMO radars. One of the most famous approaches for beampattern design is named covariance based... 

    A fast converging integrated implementation of zero-knowledge beamforming algorithm for phased-array receivers

    , Article Analog Integrated Circuits and Signal Processing ; 2019 ; 09251030 (ISSN) Ahmadikia, A ; Atarodi, M ; Sharif University of Technology
    Springer New York LLC  2019
    Abstract
    This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the... 

    A fast converging integrated implementation of zero-knowledge beamforming algorithm for phased-array receivers

    , Article Analog Integrated Circuits and Signal Processing ; 2019 ; 09251030 (ISSN) Ahmadikia, A ; Atarodi, S. M ; Sharif University of Technology
    Springer New York LLC  2019
    Abstract
    This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the... 

    Secrecy throughput maximization for full-duplex wireless powered communication networks

    , Article 2019 IEEE International Conference on Communications, ICC 2019, 20 May 2019 through 24 May 2019 ; Volume 2019-May , 2019 ; 15503607 (ISSN); 9781538680889 (ISBN) Rezaei, R ; Sun, S ; Kang, X ; Guan, Y. L ; Pakravan, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, we investigate the secrecy throughput for a full-duplex wireless powered communication network. A multi-antenna base station (BS) transmits energy towards nodes all the time and each node harvests energy prior to its transmission time slot. Nodes sequentially transmit their confidential information to the BS in presence of other nodes which are considered as potential eavesdroppers. We derive the secrecy rate and formulate the sum secrecy throughput optimization of all nodes. The optimization variables are the time slot duration and the BS beamforming during different transmission phases. The problem is non-convex and non-trivial. We propose a suboptimal approach in which the... 

    Two layers beamforming robust against direction-of-arrival mismatch

    , Article IET Signal Processing ; Volume 8, Issue 1 , 2014 , Pages 49-58 ; ISSN: 17519675 Rahmani, M ; Bastani, M. H ; Shahraini, S ; Sharif University of Technology
    Abstract
    The presence of the desired signal (DS) in the training snapshots makes the adaptive beamformer sensitive to any steering vector mismatch and dramatically reduces the convergence rate. The objective of the present study is to propose a new adaptive beamformer which is robust against direction-of-arrival (DOA) mismatch and its convergence rate is not sensitive to the presence of the DS. This method is applicable to the arrays with specific structure such as the linear array. Our approach is based on the DS elimination from the training snapshots and the sub-array beamforming technique. To accomplish this goal, a blocking matrix which converts the primary data to the DS-free data is... 

    Multicast beamformer design for coded caching

    , Article IEEE International Symposium on Information Theory - Proceedings, 17 June 2018 through 22 June 2018 ; Volume 2018-June , 2018 , Pages 1914-1918 ; 21578095 (ISSN) ; 9781538647806 (ISBN) Tolli, A ; Shariatpanahi, S. P ; Kaleva, J ; Khalaj, B ; Sharif University of Technology
    Abstract
    A single cell downlink scenario is considered where a multiple-antenna base station delivers contents to cache-enabled user terminals. Using the ideas from multi-server coded caching (CC) scheme developed for wired networks, a joint design of CC and general multicast beamforming is considered to benefit from spatial multiplexing gain, improved interference management and the global CC gain, simultaneously. The proposed multicast beamforming strategies utilize the multiantenna multicasting opportunities provided by the CC technique and optimally balance the detrimental impact of both noise and inter-stream interference from coded messages transmitted in parallel. The proposed scheme is shown... 

    Sub-optimal beamforming for 3D cylindrical arrays of dipoles including the mutual coupling effects

    , Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 1298-1302 ; 9781728115085 (ISBN) Ahmadi, N ; Poormohammad, S ; Farzaneh, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, an analytical and low cost computational antenna array beamforming method in the presence of mutual coupling has been proposed. Mutual coupling effects is taken under consideration through the induced EMF method and the concept of active element pattern. After establishing the corresponding optimization problem, the desired beamformer is obtained through solving a convex optimization. At the end, the 3D arrays of half-wave dipole elements, of different geometries are compared based on the SIR criterion  

    Sound source localization in wide-range outdoor environment using distributed sensor network

    , Article IEEE Sensors Journal ; Volume 20, Issue 4 , 2020 , Pages 2234-2246 Faraji, M. M ; Shouraki, S. B ; Iranmehr, E ; Linares Barranco, B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Sound source localization has always been one of the most challenging subjects in different fields of engineering, one of the most important of which being tracking of flying objects. This article focuses on sound source localization using fuzzy fusion and a beamforming method. It proposes a new fuzzy-based algorithm for localizing a sound source using distributed sensor nodes. Eight low-cost sensor nodes have been constructed in this study each of which consists of a microphone array to capture sound waves. Each node is able to record audio signals synchronously on an SD card to evaluate different algorithms offline. However, the sensor nodes are designed to be able to estimate the location... 

    Linear multicast beamforming schemes for coded caching

    , Article 52nd Asilomar Conference on Signals, Systems and Computers, ACSSC 2018, 28 October 2018 through 31 October 2018 ; Volume 2018-October , 2019 , Pages 172-176 ; 10586393 (ISSN); 9781538692189 (ISBN) Tolli, A ; Kaleva, J ; Shariatpanahi, S. P ; Khalaj, B ; Matthews M. B ; Sharif University of Technology
    IEEE Computer Society  2019
    Abstract
    A single cell downlink scenario is considered, where a multiple-antenna base station delivers contents to cache-enabled user terminals. Depending on the available degrees of freedom, several multicast messages are transmitted in parallel to distinct subsets of users. In the multicast beamformer design, we restrict ourselves to linear receiver implementation, which does not require successive interference cancellation unlike in the more optimal baseline scheme. With a small loss in performance, the complexity of both the receiver and transmitter implementation can be significantly reduced. © 2018 IEEE  

    Interference Reduction and Cancellation by Beamforming in Cognitive Radios

    , M.Sc. Thesis Sharif University of Technology Gavili Gilan, Adnan (Author) ; Nasiri Kenari, Masoumeh (Supervisor)
    Abstract
    Cognitive Radio (CR), as a new concept to efficiently utilize a licensed spectrum, and this has received intensive attension in recent years. By applying the cognitive technique, an unlicensed user (the secondary user (SU)) is allowed to transmit at the Primary User’s (PU) spectrum band under some conditions. Different approaches have been introduced to be utilized by the SU in order to be able to efficiently transmit at the PR’s spectrum without any sustainsial destructive effects on PR transmission and reception, which one of them is using multiple antenna in the cognitive transmitter. Hereby, CR is able to increase its throughput without substansial harmfull effect on PR’ transmission by... 

    Effect of antenna coupling on the snr improvement of Mm-wave massive MIMO for 5

    , Article 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019, 7 July 2019 through 12 July 2019 ; 2019 , Pages 417-418 ; 9781728106922 (ISBN) Ezzati, V ; Fakharzadeh, M ; Farzaneh, F ; Ranjbar Naeini, M ; IEEE Antennas and Propagation Society (APS); The Institute of Electrical and Electronics Engineers (IEEE) ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, it is shown that an optimum coupling between massive MIMO elements improves the SNR for each user in 5G downlink mode. It is assumed that a massive MIMO base station with 64 compact antennas with sub-wavelength spacing (0.37λ) serves 8 user equipments. With proper design of antennas couplings, the mean received SNR of users improves from 4 to 7 dB. Different coupling values are implemented for a sample patch antenna at 28 GHz with a slot on substrate between adjacent patch elements to control the element coupling. The whole system is simulated in MATLAB, with 5G millimeter-wave channel characteristics and OFDM modulation  

    Analysing of 3D beamforming in MIMO radars

    , Article Proceedings of the 2012 World Congress on Information and Communication Technologies, WICT 2012 ; 2012 , Pages 745-749 ; 9781467348041 (ISBN) Roshanzamir, A ; Bastani, M. H ; Roshanzamir, M ; Machine Intelligence Research Labs (MIR Labs) ; Sharif University of Technology
    2012
    Abstract
    A multiple input multiple output (MIMO) radar system is an emerging research field which has attracted many studies in recent years. This type of radar, unlike conventional phased array radar, can transmit different probing signals via its antennas, that may be correlated or uncorrelated with each other. This waveform diversity offered by MIMO radar systems enable superior capabilities compared to conventional phased array radar. Many papers have introduced different ways for beamforming of MIMO radar. In this paper it is desirable to analysis some methods for beamforming of MIMO radars with planar arrays constellation and examine their 3D result beam-pattern of such constellations for... 

    Robust relay beamforming against jamming attack

    , Article IEEE Communications Letters ; Volume 22, Issue 2 , February , 2018 , Pages 312-315 ; 10897798 (ISSN) Maleki Sadr, M. A ; Ahmadian Attari, M ; Amiri, R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In this letter, we surpass the jamming effect and also estimate the jamming channel state information by using the Kalman filtering approach. Furthermore, we design a closed-form beamforming weight for maximizing the achievable rate subject to the condition that the total relays power transmission would be below a predefined threshold level, which is formulated as a quadratically constrained quadratic program. Simulation results show the efficient performance of the proposed method for different destruction powers of the jammer by achieving the Cramér-Rao lower bound. © 1997-2012 IEEE  

    Secrecy throughput maximization for full-duplex wireless powered IOT networks under fairness constraints

    , Article IEEE Internet of Things Journal ; Volume 6, Issue 4 , 2019 , Pages 6964-6976 ; 23274662 (ISSN) Rezaei, R ; Sun, S ; Kang, X ; Guan, Y. L ; Pakravan, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, we study the secrecy throughput of a full-duplex wireless powered communication network (WPCN) for Internet of Things (IoT). The WPCN consists of a full-duplex multiantenna base station (BS) and a number of sensor nodes. The BS transmits energy all the time, and each node harvests energy prior to its transmission time slot. The nodes sequentially transmit their confidential information to the BS, and the other nodes are considered as potential eavesdroppers. We first aim to optimize the sum secrecy throughput of the nodes. The optimization variables are the duration of the time slots and the BS beamforming vectors in different time slots. The optimization problem is shown to... 

    Analysis and Design of a Multi-Beam Millimeter-Wave Antenna

    , M.Sc. Thesis Sharif University of Technology Kazemi, Hamid Reza (Author) ; Borji, Amir (Supervisor)
    Abstract
    So far, Investigations have shown that microstrip antennas (MSA) offer a lot of advantages at microwave and millimeter wave frequencies. These advantages include small size, large impedance bandwidth, high radiation efficiency, ease of fabrication, low price, and simple and easy excitation (such as probe coupling,aperture coupling or proximity coupling).Microstrip antennas are fabricated in many different shapes such as square,rectangle, circle, etc. The proposed antenna in this dissertation is a multi-beam millimeter wave antenna with annular ring strip. This antenna is a multi-beam antenna with the ability to switch between different beams. Beam direction switches by changing the position... 

    Dynamic Resource Access Algorithms in Cognitive Radio Networks by Game Theory

    , M.Sc. Thesis Sharif University of Technology Louni, Alireza (Author) ; Hossein Khalaj, Babak (Supervisor)
    Abstract
    Analysis of traditional spectrum allocation schemes shows underutilization of radio spectrum. This is main motivation behind deployment of cognitive radios and improving spectrum efficiency. One of the most important issues in cognitive radio networks is to guarantee quality of service (QoS) constraints for the primary users. Another problem which must be considered during network design is to design distributed algorithm with few amount of control messages. However, there is a tradeoff between to be distributed of algorithm and to be efficient. We have used game theory to analyze convergence, effectiveness and uniqueness of stable point of network.
    This thesis is organized in two parts.... 

    Multi-antenna interference management for coded caching

    , Article IEEE Transactions on Wireless Communications ; Volume 19, Issue 3 , 2020 , Pages 2091-2106 Tolli, A ; Shariatpanahi, S. P ; Kaleva, J ; Khalaj, B. H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    A multi-antenna broadcast channel scenario is considered where a base station delivers contents to cache-enabled user terminals. A joint design of coded caching (CC) and multigroup multicast beamforming is proposed to benefit from spatial multiplexing gain, improved interference management and the global CC gain, simultaneously. The developed general content delivery strategies utilize the multiantenna multicasting opportunities provided by the CC technique while optimally balancing the detrimental impact of both noise and inter-stream interference from coded messages transmitted in parallel. Flexible resource allocation schemes for CC are introduced where the multicast beamformer design and... 

    A new adaptive beamforming algorithm for WCDMA systems (uplink)

    , Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 145-149 ; 1424410940 (ISBN); 9781424410941 (ISBN) Ghamari Adian, M ; Sharif University of Technology
    2007
    Abstract
    In the realization of adaptive beamforming algorithms, the least-mean-squares (LMS) algorithm had been the most popular scheme used for Smart Antenna systems. This Paper proposes an alternate scheme in the form of the Normalized LMS (NLMS) algorithm with active tap detection for WCDMA systems. By taking advantage of spatial filtering, the proposed scheme promises to reduce the bandwidth required for transmitting data by improving convergence rate. The performance of the Frequency Domain NLMS algorithm in the presence of multipath effects and multiple users is analyzed using simulations. This analysis is compared to that of LMS algorithm and suggests improvement in the convergence rate and... 

    MIMO Radars Waveform Design

    , M.Sc. Thesis Sharif University of Technology Shadi, Kamal (Author) ; Behnia, F (Supervisor)
    Abstract
    MIMO radar is a next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern, is mapped into a waveform correlation matrix (R) design in the narrowband case. Therefore, waveform design in MIMO radar for beamforming could be broken into two steps, namely correlation matrix design and waveform synthesis for achieving given R. As of now, given a desired beampattern or estimated location information of targets, calculating R has been modeled as an optimization problem like SDP. Also, in some special cases like rectangular beampattern, close form solutions for...