VII International Telecommunications Symposium

In this paper, we propose an optimal Joint Call Admission Control (JCAC) in next generation wireless networks, where different radio access technologies (RAT) coexist in a colocated way, and we study the impact of the different RAT’s radius coverage area in the system performance. By assuming that each incoming service request may be admitted in its...

The high peak-to-average power ratio (PAPR) is one of the main disadvantages of OFDM systems, which reduces the transmission efficiency with non-linear power amplifiers and causes unwanted distortions and out-of-band radiation. There are many schemes proposed in the literature to mitigate this problem. However, the majority of these contributions...

This paper presents a quantum permanent compromise attack to the Blum-Micali pseudorandom generator whose security is based on the assumption of intractability of the discrete logarithm problem. The proposed attack makes use of the Grover’s quantum search extension for multiple solutions and of quantum parallelism to recover the generator’s internal...

This paper presents a numerical analysis of the dispersive effects of light polarization in optical fibers. This study analyzed the behavior of the degree of polarization using the Jones matrix method for modeling the transmission channel as a concatenation of 15 sections of polarization scramblers of PMD and PDL, using the RZ, RZ and...

High data rate systems usually employ Orthogonal Frequency Division Multiplexing and Space-Time Coding to improve the performance on a mobile time-variant frequency-selective channel. Nonlinearities introduced by the power amplifier can be minimized by performing a WashHadamard Transform on the data symbol prior the Inverse Fast Fourier Transform...

Broadband wireless systems in TV White Spaces have gained considerable attention since FCC started the process in 2004 and later 2008 published the first rules for TV band devices. Several companies, mainly in the US, are looking at the new opportunities and are putting efforts to develop standards in industry forums and IEEE. Since white spaces...

Node deployment plays an important role in the design of wireless sensor networks (WSNs). Many important properties such as coverage, connectivity, data fidelity and lifetime are directed influenced by the way nodes are placed in the sensor field. In this work we show that the use of a stochastic point process, namely the C model, is able to...

Number portability (NP) is an important requirement present in most telephony networks. Typically, NP is regulated by local legislation and is inherently against the very nature of routing in circuit-switched networks, which can complicate its deployment. The technological move towards IP-based networks demands treatment of legacy numbers...

Quantum states are very delicate, so quantum error-correction procedures are believed to be essential for the successful implementation of quantum communications or computations. To erroneous qubits where the position is known, Grassl et al. [Phys. Rev. A 56, 33 (1997)] proposed an error model which they called quantum erasure channel. In...

This paper presents a measurement system for indoor characterization of UWB channels. The presented method uses a scalar network analyzer (SNA) or a spectrum analyzer (SA) with tracking generator, connected to two antennas: a receiving and a transmitting one. This setup, which obtains only the magnitude data of the frequency response, makes the...