公开(公告)号：US10694526B2

公开(公告)日：2020-06-23

申请号：US15720951

申请日：2017-09-29

Applicant: Drexel University ,  University of Oulu

Inventor： Danh H. Nguyen ,  Anton Paatelma ,  Harri Saarnisaari ,  Nagarajan Kandasamy ,  Kapil R. Dandekar

IPC: H04W72/02 ,  H04W72/08 ,  H04W74/04 ,  H04W72/04 ,  H04W16/06 ,  G06N20/00 ,  H04L12/26 ,  G06N7/00 ,  H04W16/26 ,  H04W56/00 ,  H04L12/24 ,  G06N3/12

Abstract: A learning protocol for distributed antenna state selection in directional cognitive small-cell networks is described. Antenna state selection is formulated as a nonstationary multi-armed bandit problem and an effective solution is provided based on the adaptive pursuit method from reinforcement learning. A cognitive small cell testbed, called WARP-TDMAC, provides a useful software-defined radio package to explore the usefulness of compact, electronically reconfigurable antennas in dense small-cell configurations. A practical implementation of the adaptive pursuit method provides a robust distributed antenna state selection protocol for cognitive small-cell networks. Test results confirm that directionality provides significant advantages over omnidirectional transmission which suffers high throughput reduction and complete link outages at above-average jamming or cross-link interference power.

公开(公告)号：US09924522B2

公开(公告)日：2018-03-20

申请号：US14867801

申请日：2015-09-28

Applicant: Drexel University

Inventor： Nikhil Gulati ,  David Gonzalez ,  Kapil R. Dandekar

IPC: H04B1/44 ,  H04W72/08 ,  H01Q1/00 ,  H01Q13/20 ,  H04W24/02 ,  H04B7/0417 ,  H04B7/06

CPC classification number: H04W72/082 ,  H01Q1/007 ,  H01Q13/20 ,  H04B1/44 ,  H04B7/0417 ,  H04B7/0626 ,  H04W24/02 ,  H04W72/085

Abstract: A method for selecting the state of a reconfigurable antenna installed at either the receiver or transmitter of a communication system is provided. The proposed method uses online learning algorithm based on the theory of multi-armed bandit to perform antenna state selection. The selection technique utilizes the Post-Processing Signal-to-Noise Ratio (PPSNR) as a reward metric and maximizes the long-term average reward over time. The performance of the learning based selection technique is empirically evaluated using wireless channel data. The data is collected in an indoor environment using a 2×2 MIMO OFDM system employing highly directional metamaterial Reconfigurable Leaky Wave Antennas. The learning based selection technique shows performance improvements in terms of average PPSNR and regret over conventional heuristic policies.

公开(公告)号：US09531497B2

公开(公告)日：2016-12-27

申请号：US14290545

申请日：2014-05-29

Applicant: Drexel University

Inventor： Boris Shishkin ,  Danh H. Nguyen ,  Cem Sahin ,  Kapil R. Dandekar ,  Nagarajan Kandasamy ,  David J. Dorsey

IPC: H04B17/00 ,  H04K3/00

CPC classification number: H04K3/80 ,  H04K3/41 ,  H04K3/45 ,  H04K3/46 ,  H04K3/94 ,  H04K2203/18

Abstract: A real-time capable, protocol-aware, reactive jammer using GNU Radio and the USRP N210 software-defined radio (SDR) platform detects in-flight packets of known wireless standards and reacts to jam them—within 80 ns of detecting the signal. A reactive jamming device is achieved using low-cost, readily available hardware. The real-time reactive jamming device includes a real-time signal detector that detects an event in received packets in the wireless network, a reactive jamming device that sends a triggering signal when the event is detected, and a jamming generator responsive to the triggering signal to generate a jamming signal that has a user-defined delay so as to enable jamming of specific locations in received packets in the wireless network. The effects of three types of jamming on WiFi (802.11g) and mobile WiMAX (802.16e) networks are demonstrated and jamming performances are quantified by measuring the network throughput using the iperf software tool.

Abstract translation: 使用GNU Radio和USRP N210软件定义无线电（SDR）平台的实时功能，协议感知，反应干扰器检测已知无线标准的飞行包中的数据，并在发现信号的80 ns内对其进行响应。 使用低成本，易于获得的硬件实现无功干扰装置。 实时无功干扰装置包括检测无线网络中接收到的分组中的事件的实时信号检测器，当检测到事件时发送触发信号的无功干扰装置，以及响应于触发信号的干扰发生器 以产生具有用户定义的延迟的干扰信号，以便能够阻止无线网络中接收的分组中的特定位置。 演示了三种干扰在WiFi（802.11g）和移动WiMAX（802.16e）网络上的影响，并通过使用iperf软件工具测量网络吞吐量来量化干扰性能。

公开(公告)号：US20160021671A1

公开(公告)日：2016-01-21

申请号：US14867801

申请日：2015-09-28

Applicant: Drexel University

Inventor： Nikhil Gulati ,  David Gonzalez ,  Kapil R. Dandekar

IPC: H04W72/08 ,  H04B7/06 ,  H04B7/04

CPC classification number: H04W72/082 ,  H01Q1/007 ,  H01Q13/20 ,  H04B1/44 ,  H04B7/0417 ,  H04B7/0626 ,  H04W24/02 ,  H04W72/085

Abstract: A method for selecting the state of a reconfigurable antenna installed at either the receiver or transmitter of a communication system is provided. The proposed method uses online learning algorithm based on the theory of multi-armed bandit to perform antenna state selection. The selection technique utilizes the Post-Processing Signal-to-Noise Ratio (PPSNR) as a reward metric and maximizes the long-term average reward over time. The performance of the learning based selection technique is empirically evaluated using wireless channel data. The data is collected in an indoor environment using a 2×2 MIMO OFDM system employing highly directional metamaterial Reconfigurable Leaky Wave Antennas. The learning based selection technique shows performance improvements in terms of average PPSNR and regret over conventional heuristic policies.

Abstract translation: 提供了一种用于选择安装在通信系统的接收机或发射机处的可重新配置天线的状态的方法。 提出的方法使用基于多武装强盗理论的在线学习算法进行天线状态选择。 选择技术利用后处理信噪比（PPSNR）作为奖励度量，并使长期平均奖励随时间推移最大化。 使用无线信道数据对基于学习的选择技术的性能进行经验性评估。 使用采用高度定向的超材料可重构泄漏波天线的2×2 MIMO OFDM系统在室内环境中收集数据。 基于学习的选择技术显示了平均PPSNR的性能改进，并对传统启发式策略感到遗憾。

公开(公告)号：US20150349418A1

公开(公告)日：2015-12-03

申请号：US14653076

申请日：2013-12-20

Applicant: DREXEL UNIVERSITY ,  ADANT TECHNOLOGIES, INC.

Inventor： Damiano Patron ,  Kapil R. Dandekar ,  Daniele Piazza

IPC: H01Q3/24 ,  H01Q1/38 ,  H01Q3/44 ,  H01Q9/44

CPC classification number: H01Q3/24 ,  H01Q1/38 ,  H01Q3/44 ,  H01Q9/44 ,  H01Q21/205 ,  H01Q21/30

Abstract: A planar reconfigurable antenna that is capable of generating omnidirectional and directional radiation patterns over a wide frequency band or over multiple frequency bands includes a substrate, one or more pairs of conductive elements on at least one side of the substrate, a common RF feed point, and respective switches that selectively connects one or all of the conductive elements to the common RF feed point. An omni-directional radiation pattern is generated when all of the conductive elements are connected to the common RF feed point, while a directional radiation pattern is generated when only a pair of conductive elements on opposite sides of the substrate are connected to the common RF feed point. In the directional radiation mode, the conductive elements that are not connected to the common RF feed point act as a reflector for other conductive elements that are connected to the common RF feed point.

Abstract translation: 能够在宽频带或多个频带上产生全向和定向辐射图案的平面可重构天线包括衬底，在衬底的至少一侧上的一对或多对导电元件，公共RF馈电点， 以及各个开关，其选择性地将一个或所有导电元件连接到公共RF馈电点。 当所有导电元件连接到公共RF馈电点时，产生全向辐射图，而当基板的相对侧上仅一对导电元件连接到公共RF馈电时产生定向辐射图 点。 在定向辐射模式中，未连接到公共RF馈电点的导电元件用作连接到公共RF馈电点的其它导电元件的反射器。

公开(公告)号：US20140347240A1

公开(公告)日：2014-11-27

申请号：US14455411

申请日：2014-08-08

Applicant: Drexel University

Inventor： Kapil R. Dandekar ,  Prathaban Mookiah

IPC: H01Q1/52

CPC classification number: H01Q1/523 ,  B65D65/403 ,  H01Q1/38 ,  H01Q1/526 ,  H01Q3/44 ,  H01Q7/08 ,  H01Q9/045 ,  H01Q15/006 ,  H01Q21/28 ,  Y10T29/49004

Abstract: A magnetic permeability enhanced metamaterial is used to enhance the antenna array of a Multiple Input Multiple Output (MIMO) communication system. A rectangular patch antenna array is formed including a stack of a plurality of unit cells, where each unit cell includes an inductive loop of magnetic permeability enhanced metamaterials embedded in a host dielectric substrate. The use of such metamaterials permits the antenna arrays to be made smaller, and have less mutual coupling, when using a metamaterial substrate. The measured channel capacities of the antenna arrays are similar for the metamaterial and conventional substrates; however, the capacity improvement when using MIMO relative to single antenna communication systems is greater for antennas on metamaterial substrates.

Abstract translation: 磁导率增强超材料用于增强多输入多输出（MIMO）通信系统的天线阵列。 形成矩形贴片天线阵列，其包括多个单元电池的堆叠，其中每个单元电池包括嵌入主电介质基板中的磁导率增强的超材料的感应回路。 当使用超材料基板时，使用这种超材料允许天线阵列更小，并且具有更小的相互耦合。 天体阵列的测量通道容量对于超材料和常规基板是相似的; 然而，相对于单天线通信系统使用MIMO时的容量改进对于超材料基板上的天线而言更大。

公开(公告)号：US20140334421A1

公开(公告)日：2014-11-13

申请号：US14363144

申请日：2012-12-07

Applicant: Drexel University

Inventor： Guillermo Sosa ,  Kapil R. Dandekar ,  Magdalena Bielinski ,  Kevin Wanuga

IPC: H04L27/26 ,  H04W52/42 ,  H04W52/16 ,  H04L5/00

CPC classification number: H04L27/2618 ,  H04L5/0064 ,  H04L27/2615 ,  H04W52/16 ,  H04W52/42

Abstract: The problems of high peak to average power ratio (PAPR) in multi-carrier systems and throughput improvement in multi-carrier systems by PAPR-aware rate adaptive bit loading are addressed by implementing two symbol rotation-inversion algorithms that reduce the peak to average power ratio in multi carrier OFDM systems jointly with rate adaptation. The method combines the benefits of bit allocation and symbol rotation to reduce the PAPR in OFDM communication systems and thus improve system range and robustness to noise. When coupled with adaptive bit loading techniques, these PAPR remediation strategies can substantially increase link throughput. Symbol rotation results in more than one order of magnitude BER reduction for SISO OFDM and one order of magnitude reduction in MIMO OFDM.

Abstract translation: 通过PAPR感知速率自适应位负载，多载波系统中的高峰值平均功率比（PAPR）和多载波系统的吞吐量改善的问题通过实现两个符号旋转反演算法来解决，这两种算法降低了峰值对平均功率 多载波OFDM系统中的速率匹配率。 该方法结合了比特分配和符号旋转的优点，以减少OFDM通信系统中的PAPR，从而提高系统范围和噪声鲁棒性。 当与自适应位加载技术相结合时，这些PAPR修复策略可以显着增加链路吞吐量。 符号旋转导致SISO OFDM的BER降低超过一个数量级，MIMO OFDM中降低一个数量级。

公开(公告)号：US20230084483A1

公开(公告)日：2023-03-16

申请号：US17823976

申请日：2022-09-01

Applicant: Drexel University

Inventor： Md Abu Saleh Tajin ,  Kapil R. Dandekar

IPC: G06K7/10 ,  H01Q1/22 ,  H01Q9/04 ,  H01Q21/24

Abstract: The growing research interest in passive RFID (Radio Frequency Identification)-based devices and sensors in a diverse group of applications calls for flexibility in reader antenna performance. A low-cost, easy-to-fabricate, and pattern reconfigurable UHF (Ultra High Frequency) RFID reader antenna in the RFID ISM band (902-928 MHz in the US) may offer a 54 MHz bandwidth (890 944 MHz) and 8.9 dBi maximum gain. The reconfigurable antenna can radiate four electronically switchable radiation beams in the azimuth plane. The antenna may be LHCP (Left Hand Circularly Polarized) with axial ratio (AR) in the ranging from 0.45 dB to 7 dB in the RFID ISM band.

公开(公告)号：US11540120B2

公开(公告)日：2022-12-27

申请号：US16432509

申请日：2019-06-05

Applicant: Drexel University

Inventor： Kapil R. Dandekar ,  James J. Chacko ,  Kyle Joseph Juretus ,  Marko Jacovic ,  Cem Sahin ,  Nagarajan Kandasamy ,  Ioannis Savidis

IPC: H04W12/033 ,  G06F7/58 ,  H03M13/27 ,  H04W12/041 ,  H04L5/00

Abstract: A key-based interleaver for enhancement the security of wireless communication includes a physical layer communication channel key to provide security even when the software encryption key is compromised. A method of creating a secure communication link using a physical layer interleaving system includes implementing a key policy implementation that utilizes temporal dependency and interleaving bits using a flexible inter and intra-block data interleaver.

公开(公告)号：US10594409B2

公开(公告)日：2020-03-17

申请号：US15368015

申请日：2016-12-02

Applicant: Drexel University

Inventor： Richard Anthony Primerano ,  Moshe Kam ,  Kapil R. Dandekar ,  Cole Gindhart

IPC: H04B11/00

Abstract: Ultrasonic through metal communication systems are an effective solution for transmitting data across a metal barrier when the structural integrity of the barrier cannot be compromised by physically penetrating it. Substantial improvements in through metal communication systems have been made in recent years, enabling high speed communications of up to 15 Mbps, as well as power transmission up to 30 W across flat walls. A system is described that allows for ultrasonic through metal communication across the wall of a steel tube. Primary challenges of 1) transducer contact, 2) curvature effect on echoes, and 3) alignment are analyzed and addressed through the use of radial mode piezoelectric transducers, transducer “horns”, and Electromagnetic Acoustic Transducers (EMATs). The resulting system shows no significant loss due to changes in alignment, allows for the use of either piezoelectric transducers or EMATs externally, and achieves max data rates of approximately 600 kbps without echo equalization.