OPTIMAL PAIR-WISE SUS ALGORITHM AS PROPORTIONAL FAIR ALGORITHM FOR MU-MIMO-OFDM SYSTEMS

In this paper, we research proportional fairness of the optimal pair-wise semi-orthogonal user selection (SUS) algorithm used in the MU-MIMO-OFDM system compliant with IEEE 802.11ac standard. Zero-forcing beamforming (ZFBF) is applied in the system as a precoding technique in order to cancel user interferences. Two different scenarios are considered: homogeneous and heterogeneous. Beside the proportional fairness, a throughput performance of the MU-MIMO-OFDM system is analyzed for both scenarios too. Simulation results show that the optimal pair-wise SUS algorithm is an excellent solution to realize the trade-off between the proportional fairness among users and the achieved system throughput

DESIGNING DISTRIBUTED CONTROLLING TESTBED SYSTEM FOR SUPPLY CHAIN AND LOGISTICS IN AUTOMOTIVE INDUSTRY

The arrival of the era of autonomous robots is indisputable. In this paper, innovations in the distributed control systems realized by autonomous guided vehicles in the automotive industry are provided as proof of concept. The main goal of the considered distributed control system design is to bring all-in-one dependent and independent VDA 5050 compliant robots that are easily configurable and manageable with the web-based high-quality user interface responsive business-critical application. Special attention is paid to applying a platform to manage all autonomous IoT based robots in one seamless system. In addition, a "single point of truth" as one of the main issues of modern distributed controlled systems has been considered.

SECOND ORDER STATISTICS OF DUAL SELECTION DIVERSITY OVER CORRELATED WEIBULL FADING CHANNELS IN THE PRESENCE OF INTERFERENCE

In this paper, second order statistics of dual selection combining (SC) system applying desired signal decision algorithm are obtained for the case when that diversity system operates in Weibull interference-limited environment. Namely, a novel closed-form expression for outage probability (OP), necessary for an analysis of average fade duration (AFD), in the term of Meijer’s G-function is derived for general case in which desired signal and cochannel interference (CCI) are exposed to fading with different severities. Depending on fading environment, semi-analytical and analytical expressions for average lever crossing rate (LCR) are obtained, too. Numerical results are presented to accomplish proposed mathematical analysis and to examine the effects of system and channel parameters on concerned quantities

PERFORMANCE OF UPLINK-NOMA WITH USER PAIRING AND DATA RATE-BASED POWER SCHEME

This paper analyzes a performance of uplink power-domain non-orthogonal multiple access (NOMA) system with 2K users in which a resource allocation is taken into consideration. Since the power allocation and user pairing are tightly intertwined, they are considered as a hybrid issue. Accordingly, High-High/High-Low user pairing process precedes date rate-based power allocation. Derived closed-form expressions for the outage probabilities and the sum data rate for uplink power-domain NOMA system over a composite Fisher-Snedecor (F) fading channel are used for an extensive performance evaluation. The impact of different fading/shadowing channel conditions, various users’ positions and their number on the performance metrics is examined. Presented results have high level of generality since the F fading model provides accurate characterization of the multipath/shadowing conditions in numerous communication scenarios of interest

PERFORMANCE OF SECURE COMMUNICATION OVER LAMBDA-FISHER-SNEDECOR FADING CHANNELS

In this paper, we investigate the physical layer security (PLS) of the traditional Wyner’s wiretap channel model. Secrecy performance analysis is performed assuming a presence of an active eavesdropper trying to overhear the confidential data transmission from the source node to the predefined destination. In what follows, we derive the lower bound of the secrecy outage probability, the strictly positive secrecy capacity as well as the average secrecy capacity, over the composite a-Fisher-Snedecor (a-F) fading environment. According to the analytical results, numerical results are also shown. The impact of the path loss component, the average signal-to-noise ratios over the main/wiretap channel as well as the impact of the fading, the non-linearity of the propagation medium and the shadowing shaping parameter on the PLS metrics is examined. The overall analysis and the obtained results have a high level of generality and also a high level of applicability since the a-F distribution was recently proposed, as the best fit distribution for the channel characterization of the device-to-device wireless communication in the future Beyond 5G networks

Statistics for Ratios of Rayleigh, Rician, Nakagami-m, and Weibull Distributed Random Variables

The distributions of ratios of random variables are of interest in many areas of the sciences. In this brief paper, we present the joint probability density function (PDF) and PDF of maximum of ratios μ1=R1/r1 and μ2=R2/r2 for the cases where R1, R2, r1, and r2 are Rayleigh, Rician, Nakagami-m, and Weibull distributed random variables. Random variables R1 and R2, as well as random variables r1 and r2, are correlated. Ascertaining on the suitability of the Weibull distribution to describe fading in both indoor and outdoor environments, special attention is dedicated to the case of Weibull random variables. For this case, analytical expressions for the joint PDF, PDF of maximum, PDF of minimum, and product moments of arbitrary number of ratios μi=Ri/ri, i=1,…,L are obtained. Random variables in numerator, Ri, as well as random variables in denominator, ri, are exponentially correlated. To the best of the authors' knowledge, analytical expressions for the PDF of minimum and product moments of {μi}i=1L are novel in the open technical literature. The proposed mathematical analysis is complemented by various numerical results. An application of presented theoretical results is illustrated with respect to performance assessment of wireless systems