The Experts below are selected from a list of 5271 Experts worldwide ranked by ideXlab platform

T. Itoh - One of the best experts on this subject based on the ideXlab platform.

  • Global Time-domain full-wave analysis of microwave circuits involving highly nonlinear phenomena and EMC effects
    IEEE Transactions on Microwave Theory and Techniques, 1999
    Co-Authors: Min Chen, B. Houshmand, Yongxi Qian, T. Itoh
    Abstract:

    The Global Time-domain analysis of microwave circuits involving highly nonlinear phenomena such as injection locking and intermodulation, along with parasitic effects and electromagnetic compatibility (EMC) issues is presented in this paper. Employing the concept of equivalent sources, the device-wave interaction is characterized and incorporated into the finite-difference Time-domain method. The investigation of nonlinear phenomena is accomplished by utilizing a large-signal device circuit model. Measured results are also provided for comparisons with simulated results. The applicability of this equivalent-source algorithm for investigating EMC effects is also demonstrated. A correspondence between simulated and measured EMC phenomenon indicates the usefulness of this algorithm in providing an effective tool for real world radio-frequency front-end circuit designs.

  • Global Time-domain full-wave analysis of microwave FET oscillators and self-oscillating mixers
    1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192), 1998
    Co-Authors: Min Chen, W.r. Deal, B. Houshmand, T. Itoh
    Abstract:

    The Global Time-domain nonlinear analysis of microwave FET oscillators and self-oscillating mixers using the extended FDTD technique is presented. Employing the concept of equivalent current/voltage sources, the device-wave interaction is characterized and incorporated into the FDTD Time-stepping algorithm. Consequently, investigation of highly nonlinear phenomena, such as injection locking and intermodulation, can be accomplished by utilizing a large-signal device circuit model. Theoretical results are validated by experiments.

Min Chen - One of the best experts on this subject based on the ideXlab platform.

  • Global Time-domain full-wave analysis of microwave circuits involving highly nonlinear phenomena and EMC effects
    IEEE Transactions on Microwave Theory and Techniques, 1999
    Co-Authors: Min Chen, B. Houshmand, Yongxi Qian, T. Itoh
    Abstract:

    The Global Time-domain analysis of microwave circuits involving highly nonlinear phenomena such as injection locking and intermodulation, along with parasitic effects and electromagnetic compatibility (EMC) issues is presented in this paper. Employing the concept of equivalent sources, the device-wave interaction is characterized and incorporated into the finite-difference Time-domain method. The investigation of nonlinear phenomena is accomplished by utilizing a large-signal device circuit model. Measured results are also provided for comparisons with simulated results. The applicability of this equivalent-source algorithm for investigating EMC effects is also demonstrated. A correspondence between simulated and measured EMC phenomenon indicates the usefulness of this algorithm in providing an effective tool for real world radio-frequency front-end circuit designs.

  • Global Time-domain full-wave analysis of microwave FET oscillators and self-oscillating mixers
    1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192), 1998
    Co-Authors: Min Chen, W.r. Deal, B. Houshmand, T. Itoh
    Abstract:

    The Global Time-domain nonlinear analysis of microwave FET oscillators and self-oscillating mixers using the extended FDTD technique is presented. Employing the concept of equivalent current/voltage sources, the device-wave interaction is characterized and incorporated into the FDTD Time-stepping algorithm. Consequently, investigation of highly nonlinear phenomena, such as injection locking and intermodulation, can be accomplished by utilizing a large-signal device circuit model. Theoretical results are validated by experiments.

Mohsen Guizani - One of the best experts on this subject based on the ideXlab platform.

  • Lightweight secure Global Time synchronization for Wireless Sensor Networks
    2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012
    Co-Authors: Jie Li, Mohsen Guizani
    Abstract:

    Time synchronization is crucial to Wireless Sensor Networks (WSNs) due to the requirement of coordination between sensor nodes. Existing secure Time synchronization protocols of WSNs introduce high overhead when used for Global Time synchronization. In this paper, we propose a lightweight secure Global Time synchronization protocol for WSNs. In the proposed protocol, a broadcast synchronization packet makes all sensor nodes in the network synchronize with the trusted source. The synchronization packet is protected by a proposed broadcast authentication algorithm, which introduces asymmetry by transmitting hash values of secret keys in advance. It achieves immediate authentication and does not require the loose Time synchronization. To defend the pulse-delay attacks, the arrival Time of the synchronization packet is checked according to the estimated arrival Time interval. The upper bound on the skew of the proposed protocol is proved. The message complexity in one period of the proposed protocol is O(n) where n represents the number of sensor nodes. The simulation results show that the maximum skew is within tens of milliseconds.

  • WCNC - Lightweight secure Global Time synchronization for Wireless Sensor Networks
    2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012
    Co-Authors: Jie Li, Mohsen Guizani
    Abstract:

    Time synchronization is crucial to Wireless Sensor Networks (WSNs) due to the requirement of coordination between sensor nodes. Existing secure Time synchronization protocols of WSNs introduce high overhead when used for Global Time synchronization. In this paper, we propose a lightweight secure Global Time synchronization protocol for WSNs. In the proposed protocol, a broadcast synchronization packet makes all sensor nodes in the network synchronize with the trusted source. The synchronization packet is protected by a proposed broadcast authentication algorithm, which introduces asymmetry by transmitting hash values of secret keys in advance. It achieves immediate authentication and does not require the loose Time synchronization. To defend the pulse-delay attacks, the arrival Time of the synchronization packet is checked according to the estimated arrival Time interval. The upper bound on the skew of the proposed protocol is proved. The message complexity in one period of the proposed protocol is O(n) where n represents the number of sensor nodes. The simulation results show that the maximum skew is within tens of milliseconds.

B. Houshmand - One of the best experts on this subject based on the ideXlab platform.

  • Global Time-domain full-wave analysis of microwave circuits involving highly nonlinear phenomena and EMC effects
    IEEE Transactions on Microwave Theory and Techniques, 1999
    Co-Authors: Min Chen, B. Houshmand, Yongxi Qian, T. Itoh
    Abstract:

    The Global Time-domain analysis of microwave circuits involving highly nonlinear phenomena such as injection locking and intermodulation, along with parasitic effects and electromagnetic compatibility (EMC) issues is presented in this paper. Employing the concept of equivalent sources, the device-wave interaction is characterized and incorporated into the finite-difference Time-domain method. The investigation of nonlinear phenomena is accomplished by utilizing a large-signal device circuit model. Measured results are also provided for comparisons with simulated results. The applicability of this equivalent-source algorithm for investigating EMC effects is also demonstrated. A correspondence between simulated and measured EMC phenomenon indicates the usefulness of this algorithm in providing an effective tool for real world radio-frequency front-end circuit designs.

  • Global Time-domain full-wave analysis of microwave FET oscillators and self-oscillating mixers
    1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192), 1998
    Co-Authors: Min Chen, W.r. Deal, B. Houshmand, T. Itoh
    Abstract:

    The Global Time-domain nonlinear analysis of microwave FET oscillators and self-oscillating mixers using the extended FDTD technique is presented. Employing the concept of equivalent current/voltage sources, the device-wave interaction is characterized and incorporated into the FDTD Time-stepping algorithm. Consequently, investigation of highly nonlinear phenomena, such as injection locking and intermodulation, can be accomplished by utilizing a large-signal device circuit model. Theoretical results are validated by experiments.

Yi Song - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Distributed Global Time Synchronization Protocol in Cognitive Radio Ad Hoc Networks
    2015 IEEE Global Communications Conference (GLOBECOM), 2015
    Co-Authors: Dan Wang, Yi Song
    Abstract:

    Global Time synchronization is an important function that enables all devices in a network to have a unified Time. In traditional wireless ad hoc networks, since the spectrum is always available, the Global Time synchronization process usually can be performed without any interruption. However, in cognitive radio (CR) ad hoc networks, the Global Time synchronization process among secondary users may fail due to the dynamic spectrum availability. Therefore, the network performance will be significantly affected if Time synchronization fails. In this paper, the unique challenges in Global Time synchronization in CR ad hoc networks are addressed. A novel distributed Global Time synchronization protocol is proposed considering the unique features of CR ad hoc networks such as the traffic and the topology of primary users (PUs). An optimal root node (i.e., the node which provides the reference Time) selection scheme and an optimal Time synchronization period are designed. Moreover, under the proposed optimal root node and the optimal Time synchronization period, the synchronization delay and the impact of PUs on the Global Time synchronization performance are reduced dramatically. To the best of our knowledge, this is the first paper that investigates the Global Time synchronization issue in CR ad hoc networks that considers the unique features of CR ad hoc networks.

  • GLOBECOM - A Novel Distributed Global Time Synchronization Protocol in Cognitive Radio Ad Hoc Networks
    2015 IEEE Global Communications Conference (GLOBECOM), 2014
    Co-Authors: Dan Wang, Yi Song
    Abstract:

    Global Time synchronization is an important function that enables all devices in a network to have a unified Time. In traditional wireless ad hoc networks, since the spectrum is always available, the Global Time synchronization process usually can be performed without any interruption. However, in cognitive radio (CR) ad hoc networks, the Global Time synchronization process among secondary users may fail due to the dynamic spectrum availability. Therefore, the network performance will be significantly affected if Time synchronization fails. In this paper, the unique challenges in Global Time synchronization in CR ad hoc networks are addressed. A novel distributed Global Time synchronization protocol is proposed considering the unique features of CR ad hoc networks such as the traffic and the topology of primary users (PUs). An optimal root node (i.e., the node which provides the reference Time) selection scheme and an optimal Time synchronization period are designed. Moreover, under the proposed optimal root node and the optimal Time synchronization period, the synchronization delay and the impact of PUs on the Global Time synchronization performance are reduced dramatically. To the best of our knowledge, this is the first paper that investigates the Global Time synchronization issue in CR ad hoc networks that considers the unique features of CR ad hoc networks.