Performance Analysis of Selection Combining Over Correlated Nakagami-m Fading Channels with Constant Correlation Model for Desired Signal and Cochannel Interference

A very efficient technique that reduces fading and channel interference influence is selection diversity based on the signal to interference ratio (SIR). In this pa¬per, system performances of selection combiner (SC) over correlated Nakagami-m channels with constant correlation model are analyzed. Closed-form expressions are obtained for the output SIR probability density function (PDF) and cumulative distribution function (CDF) which is main contribution of this paper. Outage probability and the average error probability for coherent, noncoherent modulation are derived. Numerical results presented in this paper point out the effects of fading severity and cor¬relation on the system performances. The main contribu¬tion of this analysis for multibranch signal combiner is that it has been done for general case of correlated co-channel interference (CCI)

Implementation of Video Compression Standards in Digital Television

In this paper, a video compression standard used in digital television systems is discussed. Basic concepts of video compression and principles of lossy and lossless compression are given. Techniques of video compression (intraframe and interframe compression), the type of frames and principles of the bit rate compression are discussed. Characteristics of standard-definition television (SDTV), high-definition television (HDTV) and ultra-high-definition television (UHDTV) are given. The principles of the MPEG-2, MPEG-4 and High Efficiency Video Coding (HEVC) compression standards are analyzed. Overview of basic standards of video compression and the impact of compression on the quality of TV images and the number of TV channels in the multiplexes of terrestrial and satellite digital TV transmission are shown. This work is divided into six sections

CHANNEL CAPACITY OF THE MACRO-DIVERSITY SC SYSTEM IN THE PRESENCE OF KAPPA-MU FADING AND CORRELATED SLOW GAMMA FADING

In this paper macrodiversity system consisting of two microdiversity SC (Selection Combiner) receivers and one macrodiversity SC receiver are analyzed. Independent κ-μ fading and correlated slow Gamma fading are present at the inputs to the microdiversity SC receivers. For this system model, analytical expression for the probability density of the signal at the output of the macrodiversity receiver SC, and the output capacity of the macrodiversity SC receiver are calculated. The obtained results are graphically presented to show the impact of Rician κ factor, the shading severity of the channel c, the number of clusters µ and correlation coefficient ρ on the probability density of the signal at the output of the macrodiversity system and channel capacity at the output of the macrodiversity system. Based on the obtained results it is possible to analyze the real behavior of the macrodiversity system in the presence of  κ-μ fading

Association of monocyte CCR2 expression with obesity and insulin resistance in postmenopausal women

Purpose: Monocytes actively participate in inflammatory mechanisms that contribute to the development of adipose tissue dysfunction and atherogenesis. The aim of this study was to evaluate the association of monocyte CCR2 chemokine receptor expression and intracellular oxidative burst with the metabolic and inflammatory factors related to body weight. Methods: The study was performed in 67 postmenopausal women with normal, overweight and obese body mass index. Monocyte CCR2 surface expression and intracellular oxidative burst activity (determined using 2', 7'-dichlorofluorescin diacetate) were analyzed by flow cytometry. Serum levels of HMW adoponectin, monocyte chemoattractant protein-1 (MCP-1), insulin, glucose, lipids and C-reactive protein were determined. Results: Subjects with homeostasis model assessment-estimated insulin resistance (HOMA-IR) above the median had significantly higher proportion of CCR2+ monocytes and higher mean fluorescence intensity (MFI) of CCR2 and oxidative burst. The proportion of CCR2+ monocytes and CCR2 MFI were correlated with body weight, body mass index, fat mass, insulin and HOMA-IR. Oxidative burst also correlated with anthropometric measures, fat mass and expression of CCR2. No correlations were found between these markers of monocyte activation and HMW adiponectin or monocyte chemoattractant protein-1. The absolute number of monocytes was associated with insulin and this association remained significant after adjusting for C-reactive protein. In the multiple regression model the monocyte number was determined to be an independent predictor of insulin level. Conclusion: These results provide support for significant associations of monocyte number and markers involved in monocyte activation with obesity and insulin resistance

First-Order Statistical Characteristics of Macrodiversity System with Three Microdiversity MRC Receivers in the Presence of k-µ Short-Term Fading and Gamma Long-Term Fading

Macrodiversity system with macrodiversity SC receiver and three microdiversity MRC (maximum ratio combining) receivers is considered. Independent k-μ short-term fading and correlated Gamma long-term fading are present at the inputs of microdiversity MRC receivers. For this model, the probability density function and the cumulative density function of microdiversity MRC receivers and macrodiversity SC receiver output signal envelopes are calculated. Influences of Gamma shadowing severity, k-μ multipath fading severity, Rician factor and correlation coefficient at probability density function, and cumulative density function of macrodiversity SC receiver output signal envelopes are graphically presented

Analiza performansi selektirajućeg MRCS hibridnog raznolikog sustava u Riceovim kanalima

In this paper an approach to the performance analysis of hybrid MRCS (Selection Maximal Ratio Combining) diversity system operating over Ricean fading channels is presented. Hybrid MRCS combining method has a simple implementation, where maximal-ratio combined signals are chosen on a selection combining basis. Closed form expressions are provided for standard first and second order statistical measures for the signal at the output of the combiner, i.e. PDF (probability density function), CDF (cumulative distribution function), LCR (level crossing rate). Capitalizing on them standard performance measures like ABEP (Average Bit Error Probability) over some modulation techniques and AFD (Average Fade Duration) are efficiently evaluated and discussed in the function of various system parameters.U ovom radu predložen je pristup za analizu performansi hibridnog Selection Maximal Ratio Combining (MRCS) raznolikog sustava koji radi u Riceovim kanalima. Hibridna MRCS metoda je jednostavno primjenjiva, u kojoj se kombinirani signali maksimalnog omjera izabiru prema principu kombinirane selekcije. Predstavljeni su eksplicitni izrazi za standardne statističke mjere signala prvog i drugog reda, odnosno za funkciju gustoće vjerojatnosti, kumulativnu funkciju distribucije i LCR (level crossing rate). Korištenjem izvedenih izraza učinkovito su evaluirane i raspravljene standardne mjere performansi kao što je ABEP (Average Bit Error Probability) nad pojedinim tehnikama modulacije i AFD (Average Fade Duration), u funkciji različitih parametera sustava