Cesar A. Azurdia-Meza

Family of Nyquist-I Pulses to Enhance Orthogonal Frequency Division Multiplexing System Performance

ABSTRACT A family of Nyquist-I pulses called sinc parametric linear combination pulse (SPLCP) is proposed. It is characterized by two novel design parameters that provide additional degrees of freedom to minimize the intercarrier interference (ICI) power due to frequency offset. Moreover, it reduces the high peak-to-average power ratio (PAPR) value in orthogonal frequency division multiplexing (OFDM) systems. Several Nyquist-I pulses were recently proposed to address the subject of high sensitivity to frequency offset and high PAPR in OFDM-based transmissions. In this paper, we investigate the performance of SPLCP in terms of ICI power, signal-to-interference ratio (SIR) power, bit error rate (BER), and PAPR. We additionally examine the behaviour of SPLCP with new design parameters for a certain roll-off factor, α. We compare the performance of SPLCP with other well-known pulses. Theoretical and simulation results show that the proposed SPLCP outperforms other existing pulses in terms of ICI power, SIR power, BER, and PAPR.

A new location system for an underground mining environment using visible light communications

In this paper we introduce a novel localization algorithm based on visible light communications (VLC) and the trilateration technique. The new algorithm can be used for tracking people or machinery in an underground mining environment. The proposed method utilizes the concept of reference points in order to reduce the location estimation error. The proposed algorithm outperforms the LANDMARC (location identification based on dynamic active radio frequency identification (RFID) calibration) algorithm, which uses RFID tags to determine the location of an object, in terms of the location estimation error.

Performance Enhancement of OFDM-Based Systems Using Improved Parametric Linear Combination Pulses

Abstract As the demand for better performance increases in next-generation networks, such as 5G technologies, more efficient modulation techniques are required. In this work, we evaluate the performance of the improved parametric linear combination pulses (IPLCP) in orthogonal frequency division multiplexing (OFDM) based systems. OFDM-based systems are very sensitive to frequency offset errors, and are characterized by producing high peak-to-average power ratio (PAPR) values. The IPLCP is evaluated in terms of average inter-carrier interference power, average signal to interference power, PAPR, and bit error rate. Theoretical and numerical simulations show that the IPLCP pulse performs well in OFDM-based systems in comparison to other existing pulses.

Nyquist-I pulses designed to suppress the effect of ICI power in OFDM systems

Several techniques have been proposed to address the problem of high sensitivity to frequency offset in orthogonal frequency division multiplexing (OFDM) systems. Frequency offsets results in intercarrier interference (ICI) which eventually degrades the performance of the overall system. The most common approach being used to suppress the effects of ICI power in OFDM systems is a pulse-shaping technique. Two novel families of Nyquist-I pulses are proposed to minimize the ICI power and increase signal-to-interference ratio (SIR) power in OFDM-based systems. The proposed pulses are characterized by novel design parameters which provide extra degrees of freedom for a certain value of roll-off factor, α. The proposed pulses are examined with respect to ICI power and SIR in OFDM system. We evaluate and compare the performance of the proposed pulses with other recommended pulses for OFDM systems. Simulation results show that the proposed pulses performed better than other existing pulses in terms of ICI power and SIR for OFDM systems.

ICI reduction in OFDM systems using a new family of Nyquist-I pulses

In this paper we propose the improved parametric linear combination pulse (IPLCP); a new family of Nyquist pulses with two additional degrees of freedom to minimize the inter-carrier interference (ICI) power in orthogonal frequency-division multiplexing (OFDM) based systems due to frequency offset. Theoretical and numerical simulations are shown to verify that the performance of the IPLCP outperforms other existing pulses.

Evaluation of ISI-Free Parametric Linear Combination Pulses in Digital Communication Systems

Digital communication systems are characterized by having a filter at the transmitter and receiver sides to band limit the transmitted signals and diminish the effects to intersymbol interference (ISI). The optimum parametric linear combination pulse is evaluated at the transmitter and receiver sides by using different evaluation tools. The proposed pulse is evaluated in terms of the bit error rate in the presence of symbol-timing errors. Eye diagrams are presented to visually evaluate the susceptibility of the transmission system to ISI, and the maximum distortion is determined as a numerical measure of performance.

Improved Nyquist-I Pulses to Enhance the Performance of OFDM-Based Systems

Abstract Pulse shaping is used in orthogonal frequency division multiplexing (OFDM) based systems to reduce inter-carrier interference (ICI) power and peak-to-average power ratio (PAPR), which are considered the major weaknesses in OFDM-based systems. A novel family of Nyquist-I pulses called sinc exponential pulse (SEP) is proposed, and it is characterized by two new design parameters that provide extra degrees of freedom for a certain roll-off factor, α. SEP effectively decreases the relative magnitude of the two largest side lobes of the SEP frequency function, which minimizes the ICI power and reduces the PAPR in OFDM systems. Furthermore, the SEP possesses a broader main lobe, which provides sufficient improvement in bit-error-rate (BER). The behavior of the SEP is examined in the time and frequency domain by tuning its design parameters to obtain the sub-optimum SEP. Theoretical and simulation results show that the sub-optimum SEP performs better than other existing pulses in terms of ICI power, signal-to-interference ratio (SIR) power, BER, and PAPR in OFDM-based systems.

A new DNA cryptosystem based on AG codes evaluated in gaussian channels

This paper proposes a new cryptosystem system that combines DNA cryptography and algebraic curves defined over different Galois fields. The security of the proposed cryptosystem is based on the combination of DNA encoding, a compression process using a hyperelliptic curve over a Galois field

Efficient Channel Allocation Algorithm with Partial CSI for the PB/MC-CDMA System

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