Frequency hopped-chirp modulation (FH-CM) for multi-user signaling in multipath dispersive media

El‐Khamy, Said E.; Shaaban, Shawki; Thabet, E.A.

doi:10.1109/aps.1999.789162

Cited by 6 publications

(3 citation statements)

References 7 publications

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“…Authors of [14] and [15] also take into consideration the orthogonality to enhance the performance of the proposed CSS based communication systems. Contrarily, the approach of the proposed PP-CSS-MA technique resembles the work of El-Khamy et al from 1999 [17], in which the authors propose a multi-user communication system extended with frequency hopping. The benefit of this hybrid spread spectrum technique is that it improves the communication system performance especially in multipath fading dispersive channels.…”

Section: A Chirp Spread Spectrummentioning

confidence: 99%

A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation

Knapp

Pap

2018

JCOMSS

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The paper presents a new mobile communication system based on Chirp Spread Spectrum (CSS) transmission. The downlink modulation scheme is extended with Pulse Position Modulation (PPM) to carry data for multiple mobile terminals simultaneously. The described novel mechanism ensures reliable and robust communication between the parties, especially for terminals moving with high speeds or at long range. Furthermore, the proposed system take care of the uplink communication as well, where Closed-Loop Power Control (CLPC) is applied to handle the near-far problem and improve the performance of the system. Based on the attributes of the proposed system the application area covers sensor networks, IoT applications and Industry 4.0 as general field of LPWAN, however, mobility of terminals also considered. Analytical investigations for downlink communication are described focusing on the instantaneous symbol-error rate and average SER in Rayleigh fading channel. The results show that the proposed Pulse Position based Chirp Spread Spectrum technique for Multiple Access (shortly PP-CSS-MA) allows higher data rates that is used for the multiple access feature. In addition, numerical results are presented as well, and they point out the benefits of the applied CLPC mechanism. Finally, considerations regarding to the implementation of the proposed communication system are described.

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Section: A Chirp Spread Spectrummentioning

confidence: 99%

A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation

Knapp

Pap

2018

JCOMSS

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“…Chirp modulation has also been considered for multi-user. A novel form of multi-user chirp signals with the same power as well as the same bandwidth was introduced by El-Khamy et al [22][23][24]. Each signal is characterized by two different slopes, one slope for each of the two halves of the signal duration.…”

Section: Multi-user Chirp Modulation Signalsmentioning

confidence: 99%

Classification of Multi-User Chirp Modulation Signals Using Wavelet Higher-Order-Statistics Features and Artificial Intelligence Techniques

El‐Khamy¹,

Elsayed²

2012

IJCNS

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Higher order statistical features have been recently proved to be very efficient in the classification of wideband communications and radar signals with great accuracy. On the other hand, the denoising properties of the wavelet transform make WT an efficient signal processing tool in noisy environments. A novel technique for the classification of multi-user chirp modulation signals is presented in this paper. A combination of the higher order moments and cumulants of the wavelet coefficients as well as the peaks of the bispectrum and its bi-frequencies are proposed as effective features. Different types of artificial intelligence based classifiers and clustering techniques are used to identify the chirp signals of the different users. In particular, neural networks (NN), maximum likelihood (ML), k-nearest neighbor (KNN) and support vector machine (SVMs) classifiers as well as fuzzy c-means (FCM) and fuzzy k-means (FKM) clustering techniques are tested. The Simulation results show that the proposed technique is able to efficiently classify the different chirp signals in additive white Gaussian noise (AWGN) channels with high accuracy. It is shown that the NN classifier outperforms other classifiers. Also, the simulations prove that the classification based on features extracted from wavelet transform results in more accurate results than that using features directly extracted from the chirp signals, especially at low values of signal-to-noise ratios

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“…As an example for communication channel, we consider a multipath propagation medium, which can be modeled by a generalized bandpass two-ray model, which is a generalization of Rummler s effective two-ray model. In this model, the channel can be described by a transfer function H(f) that takes the form [15], H(f) = a( -be i j2(f rf) )e i2 7 fdrl Jc f > (10) and H(fi=H (-fi for f < 0, where b is the relative amplitude of the secondary ray with respect to the main ray, a is the flat fade level,is the time delay of secondary ray with respect to the main ray, fr=fc-fo, is the offset of frequency corresponding to maximum fade, fo, from the band center frequency, c, B,h is the effective channel bandwidth, ad is assumed propagation time delay assume physical realizability and, H(f/B) is a unit magnitude gate function of bandwidth B,h in the frequency domain.…”

Section: A Performance Ofmccmsignals In a Wgnmentioning

confidence: 99%

Performance of Wide Band Multi-User Frequency Hopping Chaotic Chirp Modulation (FH/MCCM) In Multipath Dispersive Media

El‐Khamy

Shaaban

Thabet

2005

EUROCON 2005 - The International Conference on "Computer as a Tool"

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New forms of multi-user chaotic chirp modulation (MCCM) signals that are characterized by the same power as well as the same bandwidth are introduced in this paper. The combination of frequency hopping spread spectrum (FHSS) techniques with (MCCM) is investigated to design a multiple-access technique that is characterized by good performance in dispersive and fading propagation media as well as reduced multiple-access interference (MAI). The new suggested frequency-hopped multi-user chaotic chirp modulation (FH/MCCM) is investigated in detail and its performance is shown to outperform that of (MCCM). Chaotic Carrier Frequency Hopping (CCFH) is used where the hopping is according to a chaotic map. Also, a novel Chaotic Slope Fast Hopping (CSFH) is also considered in which each user generate a chirp signal with a chaotic linear frequency sweeping slope.

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Frequency hopped-chirp modulation (FH-CM) for multi-user signaling in multipath dispersive media

Cited by 6 publications

References 7 publications

A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation

A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation

Classification of Multi-User Chirp Modulation Signals Using Wavelet Higher-Order-Statistics Features and Artificial Intelligence Techniques

Performance of Wide Band Multi-User Frequency Hopping Chaotic Chirp Modulation (FH/MCCM) In Multipath Dispersive Media

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