Simona Halunga

Performance evaluation for conventional and MMSE multiuser detection algorithms in imperfect reception conditions

This paper presents three multiuser detectors structures: the conventional detector, the MMSE and the adaptive detector. The error probability performances are evaluated and compared one another, as functions of signal to noise ratio, for a system with four users, and different intercorrelation coefficients and users amplitudes. Based on those simulations, a number of conclusions are drawn with respect to the effects of the intercorrelation between users or unequal amplitudes on the detectors performances.

Imperfect cross-correlation and amplitude balance effects on conventional multiuser decoder with turbo encoding

The present work aims to illustrate the improvement that turbo encoding/decoding algorithms can bring to a multiuser detection system, evaluated in terms of bit error rate (BER). Extended simulations have been performed for conventional multiuser detection algorithms and are still under study for other algorithms, like the optimal, the MMSE and the classical MMSE ones. Simulations have been performed in both optimal conditions and imperfect ones, like non-equal power of users and non-zero correlations between them and for different number of users. Several interesting conclusions have been highlighted with respect to parameters influence on overall system performances.

Single sine wave parameters estimation method based on four equally spaced samples

This article presents a general method to determine all the parameters of a single wave carrier signal i.e. the frequency, phase, amplitude and DC component, based on four different samples. The analytical formulas are derived for arbitrary samples and finally particularised for equally spaced samples. To check the fairness of our formulas, simulations have been performed in two different scenarios: when the sine-wave that is sampled is affected by white Gaussian noise and when the samples are quantised on a given number of bits. The results show that the relative error of the estimated parameters is decreasing linearly as the signal-to-noise ratio (SNR) increases, with a slope of 0.1/20 dB. When the samples are quantised on a given number of bits, the relative error is decreasing almost linearly with approximately for each extra bit in the sample representation. An increase of the number of bits is more then 15 is no longer useful since the performances are no longer increasing from that point.

Analytical formula for three points sinusoidal signals amplitude estimation errors

In this note, we show that the amplitude estimation of sinusoidal signals proposed in Wu and Hong [Wu, S.T., and Hong, J.L. (2010), ‘Five-point Amplitude Estimation of Sinusoidal Signals: With Application to LVDT Signal Conditioning’, IEEE Transactions on Instrumentation and Measurement, 59, 623–630] is a particular case of Vizireanu and Halunga [Vizireanu, D.N, and Halunga, S.V. (2011), ‘Single Sine Wave Parameters Estimation Method Based on Four Equally Spaced Samples’, International Journal of Electronics, 98(7), pp. 941–948]. An analytical formula for amplitude estimation errors as effects of sampling period deviation is obtained.

Morphological skeleton decomposition interframe interpolation method

The interframe interpolation method presented consists of partial changing, using the growing size of structuring elements, of the morphological skeleton decomposition subsets of a binary input or grayscale frame with the morphological skeleton decomposition subsets of a binary output or grayscale frame. One of the interpolated frames obtained by this method is similar to the reference frame. Computer simulations illustrate the results.

Fast communication: Nonlinear spectral subtraction method for colored noise reduction using multi-band Bark scale

We propose an improved spectral subtraction method for the reduction of colored acoustic noise added to the speech in a helicopter cockpit or in a car caused by the engine sound. Our implementation uses an over-estimation subtraction method for spectral subtraction. The noise signal does not affect uniformly the speech signal over the whole spectrum. A nonlinear multi-band Bark scale frequency spacing approach is proposed to reduce the colored noise. Simulations show a better quality in terms of Itakura-Saito distance and perceptual evaluation of quality for the enhanced speech.

Big Data, Internet of Things and Cloud Convergence --- An Architecture for Secure E-Health Applications

Big data storage and processing are considered as one of the main applications for cloud computing systems. Furthermore, the development of the Internet of Things (IoT) paradigm has advanced the research on Machine to Machine (M2M) communications and enabled novel tele-monitoring architectures for E-Health applications. However, there is a need for converging current decentralized cloud systems, general software for processing big data and IoT systems. The purpose of this paper is to analyze existing components and methods of securely integrating big data processing with cloud M2M systems based on Remote Telemetry Units (RTUs) and to propose a converged E-Health architecture built on Exalead CloudView, a search based application. Finally, we discuss the main findings of the proposed implementation and future directions.

Development of an IEEE 802.21 Media Independent Information Service

This paper provides a view on the developing process of the Media Independent Information Service, later referred as MIIS, described in the IEEE 802.21 standard, which has the main functionality of providing the mobile terminal information about all access points in his coverage area. Our approach is towards the management of the entire mechanism of delivering data to the device, that is realized at a central location. The first chapter describes related work on IEEE 802.21 standard, and it-s linkage with the MIIS entity. The following chapters present the general architecture of the system, important aspects of implementation, the used technologies and also a set of research directions. The final section presents a performance evaluation, giving us a clue about the systems real functioning and serving capabilities.

Cloud consulting: ERP and communication application integration in open source cloud systems

Cloud Consulting combines open source grid computing for distributed cloud computing and Enterprise Resource Modeling (ERP) to provide Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS) through a simple, unified API. Cloud communications refers to using internet-based or cloud-based voice and data communications services, where telecommunications applications, switching, and storage are managed generally by third parties. These services can include capabilities that range from Voice over IP (VoIP) communications to hosted PBX and unified communications delivering voice, fax, video, and data requirements. Provisioning for these services is known as Communication as a Service (CaaS).

Solution for implementing IEEE 802.21 Media Independent Information Service

This paper describes a solution for implementing the Media Independent Information Service, later referred to as MIIS, described in IEEE 802.21 standard. First we present the previous work towards defining a complete system capable of realizing a vertical handover according to the standard. Next we detail the MIIS general architecture, the information gathering procedures and considerations about the data format used in communicating. The last section presents a typical usage scenario and the advantages of implementing MIIS.