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Full-Text Articles in Computer Engineering

Power Spectral Densities Of Baseband Signals In Epc Class-1 Gen-2 Uhf Rfid Systems, Robert H. Morelos-Zaragoza Mar 2012

Power Spectral Densities Of Baseband Signals In Epc Class-1 Gen-2 Uhf Rfid Systems, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

The power spectral densities (PSD) of baseband signals in EPC Class-1 Gen-2 UHF RFID systems are shown. PSD are obtained using Matlab as the Fourier transform (via the FFT algorithm) of the autocorrelation function of random pulse sequences. The PSD of PIE, FM0 and Miller subcarrier for M=2, 4 and 8 are shown for both unipolar (for 100% ASK or OOK modulation) and polar (PSK modulation) waveforms.


Power Spectral Densities Of Baseband Signals In Epc Class-1 Gen-2 Uhf Rfid Systems, Robert H. Morelos-Zaragoza Mar 2012

Power Spectral Densities Of Baseband Signals In Epc Class-1 Gen-2 Uhf Rfid Systems, Robert H. Morelos-Zaragoza

Faculty Publications

The power spectral densities (PSD) of baseband signals in EPC Class-1 Gen-2 UHF RFID systems are shown. PSD are obtained using Matlab as the Fourier transform (via the FFT algorithm) of the autocorrelation function of random pulse sequences. The PSD of PIE, FM0 and Miller subcarrier for M=2, 4 and 8 are shown for both unipolar (for 100% ASK or OOK modulation) and polar (PSK modulation) waveforms.


On Iterative Decoding Of Two-Level Superposition Codes For Cooperative Broadcasting Based On Qpsk And 4-Pam Constellations, Robert H. Morelos-Zaragoza Nov 2010

On Iterative Decoding Of Two-Level Superposition Codes For Cooperative Broadcasting Based On Qpsk And 4-Pam Constellations, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

This paper considers iterative decoding of two-level superposition codes used in cooperative broadcasting over wireless networks. The coding scheme consists of two low-density parity-check (LDPC) codes combined using Plotkin’s |u|u+v|-construction and provides two levels of error protection.


A Trade-Off Analysis Of Energy Detectors And Partitioned Search For Primary Detection, Robert H. Morelos-Zaragoza, Birsen Sirkeci, Vishal Sawant Aug 2009

A Trade-Off Analysis Of Energy Detectors And Partitioned Search For Primary Detection, Robert H. Morelos-Zaragoza, Birsen Sirkeci, Vishal Sawant

Robert Henry Morelos-Zaragoza

Cognitive radios aim to coexist in the unused spectrum bands which are licensed to primary users without harming the primary transmission/reception. For a cognitive radio, it is important to detect the band in which the primary is operating as fast as possible and with high reliability in order to adapt its transmission. In this work, we propose P-partitioning method in combination with energy detectors for the search of the band that the primary user is operating.


An Adaptive Adjacent Channel Interference Cancellation Technique, Robert H. Morelos-Zaragoza, Shobha Kuruba May 2009

An Adaptive Adjacent Channel Interference Cancellation Technique, Robert H. Morelos-Zaragoza, Shobha Kuruba

Robert Henry Morelos-Zaragoza

In this paper, an adaptive adjacent channel interference (ACI) technique is proposed. Results for BPSK modulation with rectangular and square-root raised-cosine pulse shaping, under AWGN conditions, are obtained showing the proposed method to be effective in improving performance under high levels of interference. Basically, the idea is to send pilot signals and then to use them in estimating the amount of ACI in the frequency domain. The estimated spectral error is used to modify tap weights of an adaptive frequency-domain filter. Our simulation results reported suggest that ACI can be effectively reduced with the proposed technique. At the system level, …


Cognitive Radio: Fundamentals And Opportunities, Robert H. Morelos-Zaragoza Aug 2007

Cognitive Radio: Fundamentals And Opportunities, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

This talk is aimed at MSEE students in San Jose State University. It provides an overview of cognitive radio concepts and technologies. A MATLAB Simulink of demonstration of digital channel selection using a low IF radio architecture is presented. Technical challenges that remain to be solved in this area are identified.


Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza Mar 2004

Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

In this talk, the unique characteristics of ultra wideband (UWB) communications systems are introduced. Receiver design considerations are presented. Focus is on the relation between the symbol duration and the delay spread of the channel. This determines whether the receiver should use a Rake receiver (Spread-spectrum system) or an equalizer (multiple carrier or OFDM system).


Combined Beamforming And Space-Time Block Coding With A Sparse Array Antenna, Robert H. Morelos-Zaragoza, Mohammad Ghavami Oct 2003

Combined Beamforming And Space-Time Block Coding With A Sparse Array Antenna, Robert H. Morelos-Zaragoza, Mohammad Ghavami

Robert Henry Morelos-Zaragoza

In this paper, we continue our investigation of joint beamforming and transmit diversity with space-time block coding. In particular, the performance of a four-element array antenna is considered, in the context of an indoor wireless communication system. The main contribution is to show that transmit diversity may be practically achieved, even with correlated beams produced by a sparse array antenna.


Combined Beamforming And Space-Time Block Coding With Sparse Array Antennas, Robert H. Morelos-Zaragoza Oct 2003

Combined Beamforming And Space-Time Block Coding With Sparse Array Antennas, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

In this paper, the combination of beamforming and space-time block coding is investigated. An adaptive scheme for the assignment of transmission beams is proposed. Data for the determination of beams are obtained using a triangular switch-beam array antenna at the transmitter. The number of peak points is determined from the data and a prescribed threshold level. Orthogonal space-time block coding is then applied to the transmission beams. We examine the distribution of the number of assigned beams as a function of indoor wireless channel parameters. Also, the effects of a small number of array elements and associated correlated beams, and …


Linda Jacobson Interview Virtual Reality Evangelist, Loretta L. Lange Sep 1995

Linda Jacobson Interview Virtual Reality Evangelist, Loretta L. Lange

SWITCH

In the interview with Linda Jacobson, a Virtual Reality (VR) artist, Jacobson discusses the current and future state of VR technology’s role in the politics of the body, social identity, self, gender, class, and race. This article discusses the fact that barriers to access exist for a more diverse set of artists across race, class, and gender to engage with VR technology and the need to evolve the development platform, so artists can implement their ideas in a low-cost way. The author discusses Jaron Lanier’s ideas about using VR to explore other identities based on a theatrical model where the …