The Experts below are selected from a list of 1560 Experts worldwide ranked by ideXlab platform

R. Achar - One of the best experts on this subject based on the ideXlab platform.

  • Fast algorithm for transient analysis of Distributed interconnects including driver and load
    2007 IEEE Northeast Workshop on Circuits and Systems, 2007
    Co-Authors: L. Filipovic, R. Achar, M. Nakhla
    Abstract:

    This paper presents an efficient algorithm for computation of transient responses of multiconductor Distributed Transmission line type networks with drivers and loads. In the new method, fast computable pole-residue type relationships as a function of the multiconductor Distributed Transmission line model, driver and load are developed for evaluation of time-domain responses. The new algorithm is suitable for repetitive type of environment, where the transient responses need to be estimated for varying loads and drivers, quickly. The proposed method yields significant speed-up compared to the MNA type analysis of Distributed networks with load and driver. Numerical examples are presented to demonstrate the validity and efficiency of the proposed method.

  • Delay extraction based closed-form SPICE compatible passive macromodels for Distributed Transmission line interconnects
    Proceedings of the ASP-DAC 2005. Asia and South Pacific Design Automation Conference 2005., 2005
    Co-Authors: N. Nakhla, M. Nakhla, R. Achar, A. Dounavis
    Abstract:

    Time-domain macromodeling of highspeed interconnects characterized by Distributed Transmission lines has generated immense interest during the recent years. It has been demonstrated that, preserving passivity of the macromodel is essential to guarantee a stable global transient simulation. In this paper, a SPICE compatible closed-form passive macromodel for Distributed Transmission lines is presented. The proposed method enables representation of the Distributed stamp in terms of simple delay and resistive elements. The new method while guaranteeing the passivity of the macromodel, provides significant speedup, and enables easy implementation. Necessary formulation and validation examples are given.

  • On passive time-domain macromodels of Distributed Transmission line networks
    2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278), 2002
    Co-Authors: A. Dounavis, R. Achar, M. Nakhla
    Abstract:

    Recently, several time-domain passive macromodeling algorithms were proposed for Distributed Transmission line networks. Most of them employ some kind of approximation in the frequency-domain to match the response up to a maximum frequency of interest and the behavior after the highest frequency is generally not considered. This can cause significant errors in transient responses (especially in the early-time period). In order to address this difficulty, we will present a new algorithm to reduce these high-frequency errors in time-domain macromodels, while preserving passivity. The proposed algorithm is very useful in eliminating the spurious ripples in the flat delay portion of transient responses of Distributed Transmission line networks without needing to increase the order of approximation.

  • Addressing transient errors in passive macromodels of Distributed Transmission-line networks
    IEEE Transactions on Microwave Theory and Techniques, 2002
    Co-Authors: A. Dounavis, R. Achar
    Abstract:

    Recently, several time-domain passive macromodeling algorithms were proposed for Distributed Transmission-line networks. most or them employ some kind of approximation in the frequency domain to match the response up to a maximum frequency of interest and the behavior after the highest frequency is generally not considered. This can cause significant errors in transient responses (especially in the early-time period). In order to address this difficulty, we will present a new algorithm to reduce high-frequency errors in time-domain macromodels, while preserving passivity. The proposed algorithm is very useful in eliminating spurious ripples in the flat delay portion of transient responses of Distributed Transmission-line networks without needing to increase the order of approximation.

  • Passive model-reduction of Distributed networks with frequency-dependent parameters
    2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017), 2000
    Co-Authors: A. Dounavis, R. Achar, M. Nakhla
    Abstract:

    Accurate simulation of large interconnect networks has become a necessity to address signal integrity issues in high-speed designs. Several model-reduction techniques based on Krylov-space methods have been proposed recently for fast simulation of large linear networks. However, a major limitation of these techniques is that they cannot efficiently handle Distributed Transmission lines with frequency-dependent parameters. In order to overcome this difficulty, a new technique is presented in this paper to handle Distributed Transmission lines with frequency-dependent parameters directly in a Krylov-space based algorithm.

M.m. Krunz - One of the best experts on this subject based on the ideXlab platform.

  • A Distributed Transmission power control protocol for mobile ad hoc networks
    IEEE Transactions on Mobile Computing, 2004
    Co-Authors: A. Muqattash, M.m. Krunz
    Abstract:

    In this paper, we propose a comprehensive solution for power control in mobile ad hoc networks (MANETs). Our solution emphasizes the interplay between the MAC and network layers, whereby the MAC layer indirectly influences the selection of the next-hop by properly adjusting the power of route request packets. This is done while maintaining network connectivity. Channel-gain information obtained mainly from overheard RTS and CTS packets is used to dynamically construct the network topology. Unlike the IEEE 802.11 approach and previously proposed schemes, ours does not use the RTS/CTS packets to silence the neighboring nodes. Instead, collision avoidance information is inserted in the CTS packets and sent over an out-of-band control channel. This information is used to dynamically bound the Transmission power of potentially interfering nodes in the vicinity of a receiver. By properly estimating the required Transmission power for data packets, our protocol allows for interference-limited simultaneous Transmissions to take place in the neighborhood of a receiving node. Simulation results indicate that, compared to the IEEE 802.11 approach, the proposed protocol achieves a significant increase in the channel utilization and end-to-end network throughput and a significant decrease in the total energy consumption.

M. Nakhla - One of the best experts on this subject based on the ideXlab platform.

  • Fast algorithm for transient analysis of Distributed interconnects including driver and load
    2007 IEEE Northeast Workshop on Circuits and Systems, 2007
    Co-Authors: L. Filipovic, R. Achar, M. Nakhla
    Abstract:

    This paper presents an efficient algorithm for computation of transient responses of multiconductor Distributed Transmission line type networks with drivers and loads. In the new method, fast computable pole-residue type relationships as a function of the multiconductor Distributed Transmission line model, driver and load are developed for evaluation of time-domain responses. The new algorithm is suitable for repetitive type of environment, where the transient responses need to be estimated for varying loads and drivers, quickly. The proposed method yields significant speed-up compared to the MNA type analysis of Distributed networks with load and driver. Numerical examples are presented to demonstrate the validity and efficiency of the proposed method.

  • Delay extraction based closed-form SPICE compatible passive macromodels for Distributed Transmission line interconnects
    Proceedings of the ASP-DAC 2005. Asia and South Pacific Design Automation Conference 2005., 2005
    Co-Authors: N. Nakhla, M. Nakhla, R. Achar, A. Dounavis
    Abstract:

    Time-domain macromodeling of highspeed interconnects characterized by Distributed Transmission lines has generated immense interest during the recent years. It has been demonstrated that, preserving passivity of the macromodel is essential to guarantee a stable global transient simulation. In this paper, a SPICE compatible closed-form passive macromodel for Distributed Transmission lines is presented. The proposed method enables representation of the Distributed stamp in terms of simple delay and resistive elements. The new method while guaranteeing the passivity of the macromodel, provides significant speedup, and enables easy implementation. Necessary formulation and validation examples are given.

  • On passive time-domain macromodels of Distributed Transmission line networks
    2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278), 2002
    Co-Authors: A. Dounavis, R. Achar, M. Nakhla
    Abstract:

    Recently, several time-domain passive macromodeling algorithms were proposed for Distributed Transmission line networks. Most of them employ some kind of approximation in the frequency-domain to match the response up to a maximum frequency of interest and the behavior after the highest frequency is generally not considered. This can cause significant errors in transient responses (especially in the early-time period). In order to address this difficulty, we will present a new algorithm to reduce these high-frequency errors in time-domain macromodels, while preserving passivity. The proposed algorithm is very useful in eliminating the spurious ripples in the flat delay portion of transient responses of Distributed Transmission line networks without needing to increase the order of approximation.

  • Passive model-reduction of Distributed networks with frequency-dependent parameters
    2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017), 2000
    Co-Authors: A. Dounavis, R. Achar, M. Nakhla
    Abstract:

    Accurate simulation of large interconnect networks has become a necessity to address signal integrity issues in high-speed designs. Several model-reduction techniques based on Krylov-space methods have been proposed recently for fast simulation of large linear networks. However, a major limitation of these techniques is that they cannot efficiently handle Distributed Transmission lines with frequency-dependent parameters. In order to overcome this difficulty, a new technique is presented in this paper to handle Distributed Transmission lines with frequency-dependent parameters directly in a Krylov-space based algorithm.

  • Multi-point multi-port reduction of high-speed Distributed interconnects using Krylov-space techniques
    1999 IEEE International Symposium on Circuits and Systems (ISCAS), 1999
    Co-Authors: P.k. Gunupudi, M. Nakhla, R. Achar
    Abstract:

    Accurate simulation of large interconnect networks has become a necessity to address signal integrity issues in high-speed designs. Several model-reduction techniques based on Krylov-space methods have been proposed recently for efficient simulation of large linear networks. However a major limitation of these techniques is that they cannot handle Distributed Transmission lines directly; instead they need lumped models based on discretization of Telegrapher's equations. In order to overcome this difficulty, a new technique is presented in this paper to handle Distributed Transmission lines directly in a Krylov-space based algorithm.

Zhixing Yang - One of the best experts on this subject based on the ideXlab platform.

  • Propagation Characteristics of Distributed Transmission with Two Synchronized Transmitters
    2006 IEEE 63rd Vehicular Technology Conference, 2006
    Co-Authors: Shigang Tang, Ke Gong, Zhixing Yang
    Abstract:

    The Distributed radio Transmission scheme can improve signal coverage, as the single frequency network (SFN) for DTV broadcasting. However, the propagation characteristics of the Distributed Transmission in SFN have to be studied carefully for they are different from conventional single Transmission cases. In this paper, the field measurement carried out in a rural SFN with two synchronized transmitters is reported. It is found that, on the one hand, the radio signal coverage of the Distributed Transmission scheme has been distinctly improved with the total transmitted power by multi-transmitters as same as compared single transmitter system; and, on the other hand, the power delay profile (PDP) has shown rather different features than the single Transmission cases, in which there are long delay "echoes" and could not be modeled simply by exponential decays because of the existence of Distributed transmitters. The parameter called "Transmission gain" has been introduced in order to extend the concept of "path gain" to the Distributed Transmission cases and, the tapped delay line is used to model the average PDP in the Distributed Transmission cases

  • VTC Spring - Propagation Characteristics of Distributed Transmission with Two Synchronized Transmitters
    2006 IEEE 63rd Vehicular Technology Conference, 2006
    Co-Authors: Shigang Tang, Ke Gong, Zhixing Yang
    Abstract:

    The Distributed radio Transmission scheme can improve signal coverage, as the Single Frequency Network (SFN) for DTV broadcasting. However, the propagation characteristics of the Distributed Transmission in SFN have to be studied carefully for they are different from conventional single Transmission cases. In this paper, the field measurement carried out in a rural SFN with two synchronized transmitters is reported. It is found that, on the one hand, the radio signal coverage of the Distributed Transmission scheme has been distinctly improved with the total transmitted power by multi-transmitters as same as compared single transmitter system; and, on the other hand, the power delay profile (PDP) has shown rather different features than the single Transmission cases, in which there are long delay "echoes" and could not be modeled simply by exponential decays because of the existence of Distributed transmitters. The parameter called "Transmission gain" has been introduced in order to extend the concept of "path gain" to the Distributed Transmission cases and, the tapped delay line is used to model the average PDP in the Distributed Transmission cases.

M.a. Neifeld - One of the best experts on this subject based on the ideXlab platform.

  • A method for coordinating the Distributed Transmission of imagery
    IEEE Transactions on Image Processing, 2006
    Co-Authors: J.c. Dagher, M.w. Marcellin, M.a. Neifeld
    Abstract:

    Distributed imaging using sensor arrays is gaining popularity among various research and development communities. A common bottleneck within such an imaging sensor network is the large resulting data load. In applications for which Transmission power and/or bandwidth are constrained, this can drastically decrease the sensor network lifetime. We present an algorithm that efficiently exploits inter- and intrasensor correlation for the purpose of power-constrained Distributed Transmission of sensor-network imagery. Gains in network lifetime up to 114% are obtained when using the suggested algorithm with lossless compression. Our results also demonstrate that when lossy compression is employed, much larger gains are achieved. For example, when a normalized root-mean-squared error of 0.78% can be tolerated in the received measurements, the network lifetime increases by a factor of 2.8, as compared to the (optimized) lossless case.

  • Power-constrained Distributed Transmission of sensor-network measurements
    Frontiers in Optics, 2003
    Co-Authors: J.c. Dagher, M.w. Marcellin, M.a. Neifeld
    Abstract:

    Distributed imaging using sensor arrays is gaining rapid popularity among various research and development communities. A common bottleneck within the sensor network framework is the large resulting data size. In applications where Transmission power (and/or bandwidth) is constrained, this can drastically decrease the sensor network lifetime.