Feasibility analysis for service differentiation using an FDL bank in OBS networks

A service differentiation scheme in optical burst switching (OBS) networks, which is based on dynamic fiber delay line (FDL) assignment, is shown. The effectiveness of the scheme is validated by numerical analysis and extensive simulations. Especially, the feasibility conditions for the service differentiation scheme, which are considered as the minimum number of FDLs for each sub-FDL group, are displayed. The feasibility conditions are derived numerically, and are verified through extensive simulations. The results of extensive simulations show that the proposed scheme and the feasibility conditions are valid for service differentiation in OBS networks.

A Multimodal Approach to Communicative Interactivity Classification

The problem of modality detection in so called communicative interactivity is addressed. Multiple audio and video recordings of human communication are analyzed within this framework, based on fusion of the extracted features. At the decision level, support vector machines (SVMs) are utilized to segregate between the communication modalities. The proposed approach is verified through simulations on real world recordings.

A New Routing Metric for Satisfying Both Energy and Delay Constraints in Wireless Sensor Networks

Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this new routing metric.

A New Linear Group-Wise Parallel Interference Cancellation Detector

In this paper, a new linear group-wise parallel interference cancellation (LGPIC) detector is proposed. Four different group-detection schemes are derived, namely, the linear group matched filter PIC (LGMF-PIC) detector, the linear group decorrelator PIC (LGDEC-PIC) detector, the linear group minimum mean square error PIC (LGMMSE-PIC) detector and the linear group parallel interference cancellation weighted PIC (LGPIC-PIC) detector. The convergence behavior of the proposed detector is analyzed and conditions of convergence are derived. Finally, extensive simulations regarding the convergence behavior and the effect of the grouping on the convergence behavior of the proposed LGPIC detector are conducted.

Dynamic Sensor Self-Organization for Distributive Moving Target Tracking

To support distributive tracking of moving targets in a wireless sensor network, sensors that receive signal from the same target must collaborate to facilitate collaborative, distributed target tracking. We present an efficient dynamic sensor self-organizing algorithm that clusters sensors into groups without requiring a centralized control. Extensive simulations are conducted to verify the performance improvement as well as the communication reduction for the proposed methods.

Joint Carrier-Frequency Offset and Channel Estimation for MIMO-OFDM Transmission

In this paper, we consider a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system operating over frequency-selective fading channels. We propose a novel scheme for joint carrier-frequency offset (CFO) and channel estimation based on the expectation–maximization (EM) algorithm. Furthermore, the Cramer-Rao bounds (CRBs) for both CFO and channel estimators are exploited to evaluate the performance of the proposed scheme. Computer simulations show that the proposed algorithm achieves almost ideal performance compared with the CRBs for both channel and frequency offset estimations.

An Expression for the Average Quantization Error

The quantization error for MIMO (multiple-input multiple-output) downlink channels is known to be the minimum of independent and identically distributed beta random variables. In this note, an exact expression is derived for the average quantization error. Computational issues relating to its correctness, usage and approximations are discussed.

MGFs for Rayleigh Random Variables

Expressions are given for the moment generating functions of the Rayleigh and generalized Rayleigh distributions.

A Novel Adaptive Detection Scheme based on Parallel Interference Cancellation for V-BLAST System

In this paper, in order to reduce the computational complexity of the detector of vertical Bell Laboratories layered space-time (V-BLAST) system over time-varying channels, an adaptive detection scheme is proposed based on parallel interference cancellation (PIC). The presented scheme has three units, which are primary adaptive detector, detection ordering determiner, and adaptive PIC detector. The proposed scheme can employ many of known adaptive algorithms for detection of V-BLAST system. In this paper, we present computational complexity of the proposed scheme using LMS, RLS, APA and AMSER adaptive algorithms and evaluate its performance with numerical simulations.

Programmable CMOS CNN Cell Based on Floating-gate Inverter Unit

At present, the Cellular Neural Network (CNN) is a potential parallel structure able to perform image processing tasks in real-time when is effectively implemented in CMOS technology. The CNN silicon integration success is due mainly to the local connectivity of processing cells. In this work, an alternative design based on floating-gate MOS inverters is presented, which uses unipolar signals for solving binary tasks. The approach brings a fast response in a reduced silicon area, as shown through electrical simulations. A prototype cell in CMOS technology (AMI, 1.2 micron) was fabricated and tested for eight image processing tasks.

A Tool for Unbiased Comparison between Logarithmic and Floating-point Arithmetic

For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number systems. These libraries are freely available at .

---

Hardware Organization to Achieve High-Speed Elliptic Curve Cryptography for Mobile Devices

Elliptic curve cryptography (ECC) is recognized as a fast cryptography system and has many applications in security systems. In this paper, a novel sharing scheme is proposed to significantly reduce the number of field multiplications and the usage of lookup tables, providing high speed operations for both hardware and software realizations.

Error Probability Distribution and Density Functions for Rayleigh and Rician Fading Channels with Diversity

This paper analyzes the distribution and density functions of the probability of error for Rayleigh and Rician fading channels with diversity. An expression for the signal-to-noise ratio is derived for an asynchronous CDMA (A-CDMA) system with diversity. The error probability distribution and density functions are derived and plotted for different mean energy-to-noise ratios.

A Design-Based Structural Test Method for a Switched-Resistor DAC

In this paper, a design-based structural testing method is presented to enable a fast, low cost test for a switched-resistor digital-to-analogue converter (DAC). A 24-bit stereo DAC is used to demonstrate this. After schematic-level simulations and experimental verification, it is found that the dynamic parameter THD can be predicted by the static test. Practical production wafer test and final test results evaluate this structural test method by comparing it with the traditional THD test method. In this paper the simulation results, the relevant measurement results, and the testing results are discussed. Finally, the application recommendations are given.

Modeling Channel Access Delay and Jitter of IEEE 802.11 DCF

With the ever-increasing requirement of WLAN to support real-time services, it is becoming important to study the delay properties of WLAN protocols. This paper constructs a new model to analyze the channel access delay and delay jitter of IEEE 802.11 DCF in saturation traffic condition. Based on this analytical model, average channel access delay and delay jitter are derived for both basic access and RTS/CTS-based access scheme. The accuracy of the analytical model is validated by simulations and furthermore we discuss the impact of initial contention window, maximal backoff stage, and packet size on channel access delay and delay jitter of 802.11 DCF using the proposed model.

Improved Fractional Fourier Transform Based Receiver for Spatial Multiplexed MIMO Antenna Systems

In this work the performance of a Fractional Fourier transform (FrFT) based Minimum Mean Squared Error receiver for MIMO systems with space time processing over Rayleigh faded channels is presented. The proposed receiver called Optimum FrFT based MIMO receiver (OFMR) shows improved performance outperforming the simple MMSE receiver in Rayleigh faded channel.

Superresolution reconstruction using nonlinear gradient-based regularization

This paper discusses the problem of superresolution reconstruction. To preserve edges accurately and efficiently in the reconstruction, we propose a nonlinear gradient-based regularization that uses the gradient vector field of a preliminary high resolution image to configure a regularization matrix and compute the regularization parameters. Compared with other existing methods, it not only enhances the spatial resolution of the resulting images, but can also preserve edges and smooth noise to a greater extent. The advantages are shown in simulations and experiments with synthetic and real images.

Reducing the lightpath establishing time of FWM-aware dynamic RWA for wavelength-routed optical networks

A dynamic routing and wavelength allocation technique with an interplay between physical and network layer parameters encompassing Four-wave mixing (FWM) awareness and teletraffic performance of wavelength-routed optical networks has previously been proposed for a distributed approach. In this article, we present a fast computational algorithm for our routing and wavelength assignment (RWA) encompassing FWM-induced crosstalk. The objective is to minimize the time of establishing a dynamic lightpath. For this purpose, a precomputed matrix of FWM crosstalk products is used in an adapted version of the FWM-aware dynamic RWA algorithm. The approach is validated through simulations showing improvement up to 30–50% on the provisioning time of lightpaths for different network topologies compared to an online full computational scheme.

Performance analyses of serial-mode multicasting scheme in optical packet switched networks

The serial-mode multicasting scheme (SM), which can achieve duplication, buffering, and serial export of optical multicast packets in Optical Packet Switched (OPS) networks, is experimentally studied in this paper. Based on the experimental results, several limitations of this scheme, such as the multicast latency and signal impairment, are discussed. In addition, its performance in OPS networks is investigated by computer simulations. From the simulation results, a conclusion can be drawn that compared with the parallel-mode multicasting scheme (PM) producing multiple simultaneous copies of the optical packets by an optical power splitter or other devices, the SM scheme can increase the multicast success ratio and reduce the multicast retransmission times at the costs of some signal impairments and some extra transmission latency.

Isolation of Failing Scan Cells through Convolutional Test Response Compaction

This paper describes a non-recursive fault diagnosis technique for scan-based designs with convolutional test response compaction. The proposed approach allows a time-efficient and accurate identification of failing scan cells using Gauss–Jordan elimination method.