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Nowadays' ongoing development of mobile communications, promoted by the dramatically risen in traffic demand, impulses the deployment of networks with higher throughputs and lower latencies. In this paper, a comparison is made between LTE and LTE-Advanced systems by conducting a study about the parameters, wich at a link level influence the most the data rate experienced by the user. To do so, the LTE and LTE-Advanced Downlink Link Level Simulators developed by the Universidad Tecnológica de Vienna are employed to analyze the communication link between a single user and its Base Station. The results obtained allow to appreciate LTE-Advanced advantages when compared to LTE, given by the usage of superior transmitting modes. Thus, the capacity of MIMO techniques to exploit the intrinsic characteristics of the transmission channel is emphasized. [ABSTRACT FROM AUTHOR]

The study of optimal control techniques is of interest in various types application which required the control of complex dynamical systems, one of this cases are Unmanned Aerial Vehicles (UAV). UAV have been used in diverse fields such as: civil engineering, agriculture, disaster management, etc. Such UAV require control strategies that guarantee their stability, reject external disturbances and measurement noise. The results obtained when applying optimal control techniques to a stationary platform, powered by four motors, are presented. A comparative analysis of the results for the different controls obtained is made. For this comparison, performance specifications of the time response were used and the performance index was calculated for each implemented strategy. The analysis includes the development of the steady state platform dynamic model by means of Euler-Lagrange equations of motion, obtaining a MIMO system described by six state equations and four inputs. The first optimal control technique studied was the linear quadratic regulator (LQR) with a state-observer. This implementation required the evaluation of different performance index weight matrices Q and R until a satisfactory response of the system was obtained. The next technique studied was the implementation of the LQ controller with Kalman filter (linear quadratic Gaussian regulator, LQG) and the use of Loop Transfer Recovery (LTR) to recover the robustness characteristics of LQR. Results obtained show the viability of applying such optimal control techniques to unmanned aerial vehicles, obtaining the best results with the LQG/ LTR technique. [ABSTRACT FROM AUTHOR]

This paper presents experimental results of indoor MIMO wireless channel and channel capacity evaluation for compact PIEA (Planar Inverted "F" Antenna) antenna arrays at the 2.45 GHz frequency band. Linear and square array configurations are evaluated using PIFA antenna elements because of its advantages of low profile and flexible configuration design for compact and portable mobile terminals. Measurements are performed using a VNA with GPIB standard for automatic data acquisition. MIMO channel capacity results are calculated from a large amount of data combining uncorrelated space and frequency measurements, obtaining results that are statistically representative. Antenna array size from 0.1 to 0.8 wavelengths are tested to evaluate the effect of mutual coupling. Results show that the most efficient configurations can provide high capacity for array size as small as 0.3 to 0.4 wavelengths, which is a significant compact array size for portable wireless terminals (about 4 centimeters for the tested frequency). [ABSTRACT FROM AUTHOR]