The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

J.m.h. Elmirghani - One of the best experts on this subject based on the ideXlab platform.

  • A slotted MAC protocol for variable packet sizes over WDM metropolitan access ring networks
    Journal of optical communications, 2020
    Co-Authors: Andrés Pérez García, J.m.h. Elmirghani
    Abstract:

    This article proposes a MAC protocol that allows variable packet sizes on a WDM slotted-ring network architecture with nodes that use one Fixed Transmitter (FT) and Fixed receivers (FR). Used as a metropolitan area network (MAN), it is shown through theoretical predictions and simulation results, such as throughput, queuing delay and packet dropping probability, how this protocol allows the transmission of different packet sizes directly over an optical network. Performance for destination stripping scheme with a realistic self-similar traffic model has been simulated with the software Network Simulator (NS-2).

  • A slotted MAC protocol for efficient bandwidth utilization in WDM metropolitan access ring networks
    IEEE Journal on Selected Areas in Communications, 2003
    Co-Authors: C.s. Jelger, J.m.h. Elmirghani
    Abstract:

    The paper proposes an original wavelength-division multiplexing slotted-ring network architecture with nodes that use one Fixed Transmitter and Fixed receivers. It is shown, through theoretical predictions and simulation results, how a simple slotted medium access control protocol can be implemented to achieve fairness between access nodes and efficient bandwidth utilization when used in a metropolitan access network. Performance for both source and destination stripping schemes has been analytically derived and simulated with a realistic self-similar traffic model. A modified node architecture using a tunable receiver has also been considered and the impact of receiver collisions has been evaluated and analyzed. Finally, the effect of using unbalanced traffic sources has also been analyzed and simulated.

  • Photonic packet WDM ring networks architecture and performance
    IEEE Communications Magazine, 2002
    Co-Authors: C.s. Jeiger, J.m.h. Elmirghani
    Abstract:

    This article reviews various WDM ring architectures and pays special attention to their implementation in the metropolitan environment. A number of possible network architectures as well as protocols are reviewed. The article also proposes and analyses a WDM slotted-ring network architecture with nodes that use one Fixed Transmitter and Fixed receivers. Used as a metropolitan access network, it is shown through simulation how a simple slotted MAC protocol can be implemented in this network to achieve efficient bandwidth utilization. Throughput, delay and packet dropping probability results are presented under Poisson and self-similar traffic.

C.s. Jeiger - One of the best experts on this subject based on the ideXlab platform.

  • Photonic packet WDM ring networks architecture and performance
    IEEE Communications Magazine, 2002
    Co-Authors: C.s. Jeiger, J.m.h. Elmirghani
    Abstract:

    This article reviews various WDM ring architectures and pays special attention to their implementation in the metropolitan environment. A number of possible network architectures as well as protocols are reviewed. The article also proposes and analyses a WDM slotted-ring network architecture with nodes that use one Fixed Transmitter and Fixed receivers. Used as a metropolitan access network, it is shown through simulation how a simple slotted MAC protocol can be implemented in this network to achieve efficient bandwidth utilization. Throughput, delay and packet dropping probability results are presented under Poisson and self-similar traffic.

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

  • joint inversion of navigation and resistivity using a Fixed Transmitter and a towed receiver array a transient marine csem model study
    Geophysical Journal International, 2011
    Co-Authors: Andrei Swidinsky, Nigel R Edwards
    Abstract:

    A typical marine controlled-source electromagnetic system consists of an electric dipole Transmitter and one or more electric dipole receivers. The objective of a survey is to determine the seafloor resistivity by recording the electromagnetic transients, which diffuse through the earth from the Transmitter to the receivers. Accurate knowledge of system geometry is crucial for proper interpretation; errors in the position and orientation of the Transmitter and/or the receivers propagate into errors in the predicted seafloor resistivity. We show theoretically that for certain multireceiver set-ups and crustal electrical profiles that the geometry and the seafloor resistivity may be determined independently. A specific example is an experiment proposed in association with NEPTUNE Canada. Here, we have already deployed an electric dipole Transmitter with a known orientation in a known location. A cabled streamer of receivers may be towed by a survey vessel in the vicinity of the Transmitter on a known heading. For this configuration, an eigenparameter analysis of two seafloor models consisting of (1) a halfspace and (2) a resistive layer buried within a halfspace shows that the resistivity structure of the seafloor can be independently resolved from the cable location. Further studies of these two models also indicate that the position of the streamer must be roughly known in advance on the order of a hundred metres to be used as a suitable starting model in a non-linear inversion. The crucial information is contained in the parts of the pulse which travel through the seawater and which act as a calibration path. Such information is absent for a static DC method.

C.s. Jelger - One of the best experts on this subject based on the ideXlab platform.

  • A slotted MAC protocol for efficient bandwidth utilization in WDM metropolitan access ring networks
    IEEE Journal on Selected Areas in Communications, 2003
    Co-Authors: C.s. Jelger, J.m.h. Elmirghani
    Abstract:

    The paper proposes an original wavelength-division multiplexing slotted-ring network architecture with nodes that use one Fixed Transmitter and Fixed receivers. It is shown, through theoretical predictions and simulation results, how a simple slotted medium access control protocol can be implemented to achieve fairness between access nodes and efficient bandwidth utilization when used in a metropolitan access network. Performance for both source and destination stripping schemes has been analytically derived and simulated with a realistic self-similar traffic model. A modified node architecture using a tunable receiver has also been considered and the impact of receiver collisions has been evaluated and analyzed. Finally, the effect of using unbalanced traffic sources has also been analyzed and simulated.

G.l. Siqueira - One of the best experts on this subject based on the ideXlab platform.

  • An experimental study of the propagation of 55 GHz millimeter waves in an urban mobile radio environment
    IEEE Transactions on Vehicular Technology, 1994
    Co-Authors: H.j. Thomas, R.s. Cole, G.l. Siqueira
    Abstract:

    An experimental study of the propagation of 55 GHz millimeter waves between a Fixed Transmitter and a mobile receiver in an urban environment is described. Ranges up to 400 m are used and measurements of the received signal's "fast fading" envelope, "local mean," signal versus distance power law, and coherence bandwidth are obtained in the presence of traffic.

  • Polarization diversity for urban millimetric mobile radio communications: comparison of initial propagation measurement results with prediction
    [1992 Proceedings] Vehicular Technology Society 42nd VTS Conference - Frontiers of Technology, 1992
    Co-Authors: H.j. Thomas, G.l. Siqueira, R.s. Cole
    Abstract:

    An experimental study of the propagation of vertical and horizontal polarized 55-GHz millimeter waves from a Fixed Transmitter to a mobile receiver in an urban environment is described. Ranges up to 400 m were used and measurements were obtained in the presence of traffic. Components transmitted received on orthogonal polarizations are uncorrelated. Cross coupling components are on average 10-20 dB lower than co-coupling components and are also uncorrelated. Low cross-polarization levels suggest that propagation is dominated by interference between the direct line-of-sight (LOS) path and specular reflections from the road surface and sides of the street. Similarity of experiment results with prediction of a simple vector model of the direct path and principle specular reflections also supports this observation. At very close range, when the received signal is dominated by LOS propagation, the highest measured correlation is 0.47.