Wideband chirp modulation for FH-CDMA wireless systems: coherent and non-coherent receiver structures

Gupta, Chitrak; Mumtaz, T.; Zaman, M.; Papandreou-Suppappola, Antonia

doi:10.1109/icc.2003.1204388

Cited by 20 publications

(11 citation statements)

References 15 publications

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“…A nonlinear frequency-modulated signaling scheme is developed in [11] by deriving constraints on the nonlinear phase function of the transmit signal to achieve orthogonality; the scheme, combined with frequency-hopping CDMA, is used in a multi-user communication scheme in [11,12]. In [13], chirp modulation, with a zero cross-correlation condition, is combined with CDMA for frequency-nonselective and frequency-selective fading channels.…”

Section: Motivation and Relation To Prior Workmentioning

confidence: 99%

“…The different users are distinguished by a unique pseudo-noise (PN) sequence [9]. As we demonstrate, the scheme can successfully resolve information bits at the receiver side, but the performance degrades as the number of users increases.A nonlinear frequency-modulated signaling scheme is developed in [11] by deriving constraints on the nonlinear phase function of the transmit signal to achieve orthogonality; the scheme, combined with frequency-hopping CDMA, is used in a multi-user communication scheme in [11,12]. In [13], chirp modulation, with a zero cross-correlation condition, is combined with CDMA for frequency-nonselective and frequency-selective fading channels.…”

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confidence: 99%

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Hyperbolic frequency modulation for multiple users in underwater acoustic communications

Zhou

Zhang

Papandreou-Suppappola

2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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Nonlinear frequency-modulated signals have been effectively applied in multiple-user communication schemes. In this paper, we propose to implement a multiple-user communication scheme using hyperbolic frequency-modulated (HFM) signals for underwater acoustic communications. We derive constraints on the HFM parameters to optimally reduce multiple access interference (MAI) at the transmission side. Additional constraints on the frequency-modulation (FM) rate reduce the underwater channel effects of multipath and scaling. The proposed signaling scheme is compared to an HFM-based code-division multiple-access (HFM-CDMA) scheme to demonstrate improved error performance. MOTIVATION AND RELATION TO PRIOR WORKUnderwater acoustic (UWA) communications methods, such as orthogonal frequency-division multiplexing (OFDM) and code-division multiple access (CDMA), have been widelyused for multiple users [1][2][3][4]. As the UWA communications channel is highly time-varying, it can cause undesirable distortions, such as multipath and Doppler scaling, under certain conditions [5][6][7]. Existing UWA communications schemes do not fully exploit matching the UWA channel characteristics to signaling schemes and often have to compensate for that at the receiver. In [1], the distorted OFDM signal due to Doppler is compensated at the receiver using resampling, and any remaining Doppler is removed using inter-carrier interference reduction techniques. A multiple resampling OFDM receiver front-end is designed in [2] such that each resampling branch deals with a different Doppler factor. Adaptive multi-user detection techniques are applied in [3], but their assumed UWA channel model does not include multiple Doppler paths at the receiver. A spread spectrum hyperbolic frequency modulation scheme in [8] can potentially match the UWA channel but only assumes one Doppler scale path and does not compensate for multiple time delay paths that can distort any potential scale diversity. In [9], we design an HFM scheme to match the This work is funded by the National Science Foundation grant NSF-ECCS 1102357.UWA communications channel. The HFM scheme is integrated with the use of a discrete time-scale canonical model, which represents the received signal from a wideband channel as a linear superposition of discrete time shifts and Doppler scalings of the transmitted signal, weighted by the wideband spreading function (WSF) [10]. We demonstrate an inherent joint multipath-scale diversity using this scheme, and we combine it with direct sequence CDMA for use in multi-user UWA communications. The different users are distinguished by a unique pseudo-noise (PN) sequence [9]. As we demonstrate, the scheme can successfully resolve information bits at the receiver side, but the performance degrades as the number of users increases.A nonlinear frequency-modulated signaling scheme is developed in [11] by deriving constraints on the nonlinear phase function of the transmit signal to achieve orthogonality; the scheme, combined with frequency-hopping CDMA, is use...

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Section: Motivation and Relation To Prior Workmentioning

confidence: 99%

mentioning

confidence: 99%

Hyperbolic frequency modulation for multiple users in underwater acoustic communications

Zhou

Zhang

Papandreou-Suppappola

2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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“…Note that the superscript , in and denotes a distinct chirp and its corresponding chirp rate for User . This user can be uniquely identified from the assigned chirp rates in (2) that are chosen as [11], [12] (3)…”

Section: A Chirp Modulation Schemementioning

confidence: 99%

“…For example, for sonar echo ranging, chirps can provide more accurate range and Doppler resolution estimates than other pulses [7]. Chirps are also used in communications [8]- [11] as they resist jamming, are bandwidth-efficient, do not need synchronization [8], and have more negative cross correlation properties as compared to sinusoids [9] and an inherent immunity against Doppler and multipath fading. In [10], chirps were used for multiple access in FH spread-spectrum systems by assigning unique FM rates to different users with only one spreading sequence for all users.…”

Section: Introductionmentioning

confidence: 99%

Time-Varying Multichirp Rate Modulation for Multiple Access Systems

Shen

Machineni

Gupta

et al. 2004

IEEE Signal Process. Lett.

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We propose a modulation scheme that is based on wideband time-varying chirp signals for use in frequency-hopped code division multiple-access systems. The scheme is designed such that each user is assigned unique modulating chirp signals that efficiently occupy the hop bandwidth for identification at the receiver. We explain how the chirp modulation reduces multiple-access interference, and we demonstrate with simulations our improved performance for various fading channels. The bandwidth efficiency of the chirp signaling is further exploited by assigning multiple chirp rates to each user.Index Terms-Frequency-hopped code division multiple-access (FH-CDMA), linear chirp, multiple-access interference (MAI), time-varying.

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“…It is shown that chirp BOK performs better than the traditional BOK modulation in Additive White Gaussian Noise (AWGN) channel. Gupta, Mumtaz, Zaman and Papandreou-Suppappola [6] have evaluated the performance of chirp modulation in a frequency-hopped CDMA over several channel models.The error performance of chirp modulation over fading channels are investigated in [7]. The performance analysis with closedform bit error probability expressions for Chirp modulation in the maximum ratio combining (MRC) diversity system has been investigated in [8].…”

Section: Introductionmentioning

confidence: 99%

M-ary chirp modulation for coherent and non-coherent data transmission

Alsharef

Rao

2015

2015 IEEE 28th Canadian Conference on Electrical and Computer Engineering (CCECE)

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M -ary chirp modulated signals are described and illustrated as a function of modulation parameters-h, the peak-topeak frequency deviation divided by the symbol rate; and w, the frequency sweep width divided by the symbol rate. The detection of these signals in AWGN channel is addressed and optimum receiver structures for both coherent and non-coherent cases are derived. Closed-form expressions for symbol error probabilities for these receivers have been obtained. Optimum 2−, 4−, and 8−ary coherent chirp systems that minimize symbol error rate have been determined. The performances of both coherent and non-coherent M -ary chirp systems are compared with respective conventional M -ary digital modulations.

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Wideband chirp modulation for FH-CDMA wireless systems: coherent and non-coherent receiver structures

Cited by 20 publications

References 15 publications

Hyperbolic frequency modulation for multiple users in underwater acoustic communications

Hyperbolic frequency modulation for multiple users in underwater acoustic communications

Time-Varying Multichirp Rate Modulation for Multiple Access Systems

M-ary chirp modulation for coherent and non-coherent data transmission

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