VII International Telecommunications Symposium

This paper presents a beamforming algorithm for antenna arrays attending to both power and signal-tointerference-plus-noise (SNIR) ratio constraints. The proposed adaptive approach makes use of the least-mean-square (LMS) algorithm as well as exploits the duality idea between uplink and downlink channels. Since a reference signal is used,...

The behavior of variable step-size least-mean-square (VSSLMS) algorithms is strongly affected by measurement noise. Thereby, aiming to maintain an adequate performance of these algorithms, their parameters must be adjusted whenever changes occur in the signal-to-noise ratio (SNR) of the adaptive system. A well-known VSSLMS algorithm based on error...

Linear precoding can be applied to multicarrier systems to minimize the effect that a deep fade in one of the subchannels can have on the overall bit error ratio when the transmitter does not have channel state information (CSI). But for filterbank multicarrier (FBMC) systems, which were proposed to overcome the poor spectral characteristics...

We propose an automatic engine for panoramic-take detection which relies on an algorithm based on phase correlation and boosting. The motion between two sequential video frames is first estimated through a phase correlation. Then, we are able to extract motion parameters and apply post-processing operations on these parameters in order to feed an...

Energy availability is the main delimiter for usage time of mobile devices. As wireless network interfaces are usually the most power-demanding subsystem in a mobile device, mechanisms for their power consumption optimization are extensively researched. However, determining the power saving gains from using such optimizations is not an easy task,...

This paper outlines a low-cost technique for detection/demodulation of high-order square M-ary quadrature amplitude modulation (M-QAM), M = 4, 16, 64, 256, 1024, and 4096, in a field programmable gate array (FPGA) device. Hence, it is very interesting for advancing high-speed power line communication technology. The proposed technique is based on a...

This article has two main purposes: (i) to introduce and evaluate a modified version of the Dorsch soft decoding algorithm for block codes, based on information sets, and (ii) to examine the complexity of implementing this kind of decoder in hardware (more specifically, in FPGA devices). The modifications introduced in the algorithm lead to an...

In Brazil, the introduction of telecommunication and electric energy regulations for power line communications (PLC) is pushing forward R&D efforts towards the development of this technology. Therefore, the will to improve the usage of the regulated spectrum and its further increase, combined to the necessity of PLC system coexistence with other...

In this paper we propose an inverse QR decomposition based recursive least squares algorithm (IQRD-RLS) for the linearly constrained minimum variance (LCMV) receiver for CDMA transmission systems. The proposed algorithm is numerically stable in finite precision environments and it is suitable for implementation in systolic arrays or DSP vector...

This paper investigates the inclusion of dynamic features in the input vectors used by the multiple classification scheme which employ the null space to combine the likelihoods. Speaker identification experiments were performed considering four ambient noise and also different mismatched conditions. The results show that this strategy can contribute...