scholarly journals A Comparison Performance Analysis of QoS WLANs: Approaches with Enhanced Features

2007 ◽  
Vol 2007 ◽  
pp. 1-13 ◽  
Author(s):  
Ioannis Papapanagiotou ◽  
Georgios S. Paschos ◽  
Michael Devetsikiotis
Keyword(s):  
Performance Analysis ◽  
Complexity Theory ◽  
Queuing Theory ◽  
Ieee 802.11E ◽  
Complex Frequency ◽  
The Novel ◽  
Scientific Interest ◽  
Mac Layer ◽  
Distance Method ◽  
First Order

The main contribution of this work is to compare and enhance known methods for performance analysis of the IEEE 802.11e MAC layer, such as the use of Markov chains, queuing theory, and probabilistic analysis. It is the first paper that bases its outputs upon comparison of metrics such as complexity, flexibility, and accuracy, leading to the novel use of a metamodeling comparison. For the analysis, complexity theory and theL-square distance method for accuracy are used. In addition, the proposed analyses carry by themselves scientific interest, because they are extended enhancements with the latest EDCA parameters. A form of the PMF of the MAC delay and first-order moments are found using the PGF complex frequency domain function. The analyses incorporate a Gaussian erroneous channel in order to reflect the real conditions of the MAC layer.

Simulation Implementation and Performance Analysis of IEEE 802.11e EDCA Protocol

2011 ◽  
Vol 58-60 ◽  
pp. 1429-1434
Author(s):  
Jin Hua Zhou ◽  
Lei Lei ◽  
Wei Kang Liu ◽  
Li Bin Tao
Keyword(s):  
Performance Analysis ◽  
Ad Hoc ◽  
Multimedia Applications ◽  
Ieee 802.11E ◽  
Mac Layer ◽  
Excellent Performance ◽  
Qos Guarantee ◽  
Mobile Ad Hoc ◽  
And Performance ◽  
Hoc Networks

In this paper, we focus on IEEE 802.11e enhanced distributed channel access (EDCA) protocol, which can provide QoS guarantee for multimedia applications in mobile ad hoc networks. First, we briefly explain the concept of EDCA protocol. Then we implement EDCA protocol in GloMoSim via configuring special contention parameters for multimedia applications and introducing a virtual collision disposal mechanism in the MAC layer. In the end, we provide performance analysis for EDCA protocol through plentiful simulations. The simulation results show an excellent performance of the EDCA protocol we proposed.

scholarly journals Enabling Parallelized-QEMU for Hardware/Software Co-Simulation Virtual Platforms

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 759
Author(s):  
Edel Díaz ◽  
Raúl Mateos ◽  
Emilio J. Bueno ◽  
Rubén Nieto
Keyword(s):  
Performance Analysis ◽  
Industrial Application ◽  
The Novel ◽  
San Jose ◽  
Synchronization Mechanism ◽  
Grid Monitoring ◽  
Parallel Mode ◽  
Software And Hardware ◽  
Software Emulator ◽  
Dual Core

Presently, the trend is to increase the number of cores per chip. This growth is appreciated in Multi-Processor System-On-Chips (MPSoC), composed of more cores in heterogeneous and homogeneous architectures in recent years. Thus, the difficulty of verification of this type of system has been great. The hardware/software co-simulation Virtual Platforms (VP) are presented as a perfect solution to address this complexity, allowing verification by simulation/emulation of software and hardware in the same environment. Some works parallelized the software emulator to reduce the verification times. An example of this parallelization is the QEMU (Quick EMUlator) tool. However, there is no solution to synchronize QEMU with the hardware simulator in this new parallel mode. This work analyzes the current software emulators and presents a new method to allow an external synchronization of QEMU in its parallelized mode. Timing details of the cores are taken into account. In addition, performance analysis of the software emulator with the new synchronization mechanism is presented, using: (1) a boot Linux for MPSoC Zynq-7000 (dual-core ARM Cortex-A9) (Xilinx, San Jose, CA, USA); (2) an FPGA-Linux co-simulation of a power grid monitoring system that is subsequently implemented in an industrial application. The results show that the novel synchronization mechanism does not add any appreciable computational load and enables parallelized-QEMU in hardware/software co-simulation virtual platforms.

scholarly journals Performance Degradation in Cross-Eye Jamming Due to Amplitude/Phase Instability between Jammer Antennas

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5027
Author(s):  
Je-An Kim ◽  
Joon-Ho Lee
Keyword(s):  
Performance Analysis ◽  
Phase Difference ◽  
Taylor Expansion ◽  
Amplitude Ratio ◽  
Random Variables ◽  
Performance Degradation ◽  
Analytical Performance ◽  
Phase Instability ◽  
Gaussian Random Variables ◽  
First Order

Cross-eye gain in cross-eye jamming systems is highly dependent on amplitude ratio and the phase difference between jammer antennas. It is well known that cross-eye jamming is most effective for the amplitude ratio of unity and phase difference of 180 degrees. It is assumed that the instabilities in the amplitude ratio and phase difference can be modeled as zero-mean Gaussian random variables. In this paper, we not only quantitatively analyze the effect of amplitude ratio instability and phase difference instability on performance degradation in terms of reduction in cross-eye gain but also proceed with analytical performance analysis based on the first order and second-order Taylor expansion.

scholarly journals Performance Analysis of IEEE 802.11e Contention-Based Channel Access

2004 ◽  
Vol 22 (10) ◽  
pp. 2095-2106 ◽  
Author(s):  
Z. Kong ◽  
D.H.-K. Tsang ◽  
B. Bensaou ◽  
D. Gao
Keyword(s):  
Performance Analysis ◽  
Ieee 802.11E ◽  
Channel Access

scholarly journals ON SUPERLUMINAL FERMIONS WITHIN THE SECOND DERIVATIVE EQUATION

2012 ◽  
Vol 27 (14) ◽  
pp. 1250081 ◽  
Author(s):  
S. I. KRUGLOV
Keyword(s):  
Energy Momentum Tensor ◽  
Canonical Quantization ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Order Equation ◽  
Quantum Mechanical ◽  
Projection Operators ◽  
The Novel ◽  
First Order ◽  
Electromagnetic Interactions

We postulate the second-order derivative equation with four parameters for spin-1/2 fermions possessing two mass states. For some choice of parameters fermions propagate with the superluminal speed. Thus, the novel tachyonic equation is suggested. The relativistic 20-component first-order wave equation is formulated and projection operators extracting states with definite energy and spin projections are obtained. The Lagrangian formulation of the first-order equation is presented and the electric current and energy–momentum tensor are found. The minimal and nonminimal electromagnetic interactions of fermions are considered and Schrödinger's form of the equation and the quantum-mechanical Hamiltonian are obtained. The canonical quantization of the field in the first-order formalism is performed and we find the vacuum expectation of chronological pairing of operators.

Application of unsplit convolutional perfectly matched layer for scalar arbitrarily wide-angle wave equation

Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. T313-T321 ◽  
Author(s):  
Hanming Chen ◽  
Hui Zhou ◽  
Yanqi Li
Keyword(s):  
Wave Equation ◽  
Computational Cost ◽  
Grazing Incidence ◽  
Equation System ◽  
Perfectly Matched Layer ◽  
Staggered Grid ◽  
Complex Frequency ◽  
Wide Angle ◽  
First Order ◽  
General Complex

A classical split perfectly matched layer (PML) method has recently been applied to the scalar arbitrarily wide-angle wave equation (AWWE) in terms of displacement. However, the classical split PML obviously increases computational cost and cannot efficiently absorb waves propagating into the absorbing layer at grazing incidence. Our goal was to improve the computational efficiency of AWWE and to enhance the suppression of edge reflections by applying a convolutional PML (CPML). We reformulated the original AWWE as a first-order formulation and incorporated the CPML with a general complex frequency shifted stretching operator into the renewed formulation. A staggered-grid finite-difference (FD) method was adopted to discretize the first-order equation system. For wavefield depth continuation, the first-order AWWE with the CPML saved memory compared with the original second-order AWWE with the conventional split PML. With the help of numerical examples, we verified the correctness of the staggered-grid FD method and concluded that the CPML can efficiently absorb evanescent and propagating waves.

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