Interference Avoidance via Adaptive Wavelet Packet Modulation in Wireless Communication Systems

Abstract-This paper addresses the problem of adaptive modulation/demodulation scheme in the presence of interferences for wireless communication systems. We developed an adaptive modulation/demodulation scheme which modifies users' signature waveforms by maximizing the signal to interference ratio based on wavelet packet analysis and the state-of-art interference avoidance algorithms

Performance investigation of WOFDM for 5G wireless networks

Nowadays, emerging wireless networks scenarios such as the proposed systems for 5G is discussed widely with diverse requirements. Orthogonal Frequency Division Multiplexing (OFDM) is a conservative proposal which is used to build 5G WOFDM system (Wavelet OFDM system). The simulation of the system is initialized with BPSK then with QAM and 64-QAM the system is improved by increasing the number of levels of Discrete Wavelet Transform to five levels and finally compared with original system to prove that the it is convenient for 5G Wireless networks

Noise (AWGN) Avoidance in CDMA Systems Using the Mechanism of Spread Spectrum

In today communication systems the most probable problems are that of channel capacity, jamming and interference or noise. The channel capacity can be maximized by multiplexing the channel. While the jamming problem and for noise reduction the most important technique that we can apply is spread spectrum. That by spreading the spectrum of the original message signal, the impact of noise upon the message signal can be reduced. For that purpose, two different techniques that is DSSS(Direct Sequence Spread Spectrum) and FHSS (Frequency Hoping Spread Spectrum) can be applied. Since the two approaches are core ideas upon which CDMA system is based, so in this paper we have analyzed both the techniques to observe that h up to what extent they are efficacious in removing AWGN in CDMA systems communication. IndexTerms:DSSS, FHSS, Code Division Multiple Access (CDMA), Additive White Gaussian Noise (AWGN), spread spectrum

PERFORMANCE ASSESSMENT OF DFT-OFDM AND DWT-OFDM SYSTEMS IN THE PRESENCE OF THE HPA NONLINEARITY

This paper investigates performance degradation of conventional Orthogonal Frequency Division Multiplexing (OFDM) and Discrete Wavelet Transform based OFDM (DWT-OFDM) systems when the signals are passed through a nonlinear High Power Amplifier (HPA). In the case of DWT-OFDM, several wavelets such as Daubechies, Symlet and Bi orthogonal are evaluated. Simulation results show that DWT-OFDM  is more robust against nonlinearity in comparison to DFT-OFDM

Who wrote this scientific text?

The IEEE bibliographic database contains a number of proven duplications with indication of the original paper(s) copied. This corpus is used to test a method for the detection of hidden intertextuality (commonly named "plagiarism"). The intertextual distance, combined with the sliding window and with various classification techniques, identifies these duplications with a very low risk of error. These experiments also show that several factors blur the identity of the scientific author, including variable group authorship and the high levels of intertextuality accepted, and sometimes desired, in scientific papers on the same topic

L'intertextualité dans les publications scientifiques

La base de données bibliographiques de l'IEEE contient un certain nombre de duplications avérées avec indication des originaux copiés. Ce corpus est utilisé pour tester une méthode d'attribution d'auteur. La combinaison de la distance intertextuelle avec la fenêtre glissante et diverses techniques de classification permet d'identifier ces duplications avec un risque d'erreur très faible. Cette expérience montre également que plusieurs facteurs brouillent l'identité de l'auteur scientifique, notamment des collectifs de chercheurs à géométrie variable et une forte dose d'intertextualité acceptée voire recherchée

Adaptive Wavelet Packet Modulation

International audienceIn this paper, we propose a new adaptive modulation based on the wavelet packet transform, which targets a good resistance against frequency selective channels while avoiding a large PAPR. Classical multi-carrier modulation schemes divide the channel bandwidth into narrowband sub-channels to improve its robustness against frequency selective fading. However, they suffer from the peak-to-average power ratio (PAPR) problem which occurs due to a random constructive addition of sub-carriers. By contrast, single carrier modulation schemes, where each transmitted symbol fully occupies the bandwidth, are more sensitive to frequency selective environments and less affected by the PAPR problem. In this work, we show how the bandwidth division can be reconfigurable and adapted to the channel properties, and we provide several examples to prove that the proposed adaptive modulation represents an alternative modulation which is adjustable between two extreme cases: single carrier modulation and classical multi-carrier modulation