Physical Layer Considerations for Cognitive Radio: Modulation Techniques

Kollár, Zsolt; Horváth, Péter

doi:10.1109/vetecs.2011.5956489

Cited by 12 publications

(15 citation statements)

References 6 publications

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“…Considering high values of N and according to the central limit theorem [7], the superposition of these independent streams leads to a complex Gaussian multicarrier signal. For this reason, OFDM and FBMC/OQAM exhibit large peak-to-average power ratios (PAPR) [8][9][10], i.e., large fluctuations in their signal envelope, making both modulations very sensitive to nonlinear distortion (NLD) caused by a high-power amplifier (HPA).…”

Section: Introductionmentioning

confidence: 99%

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Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

Bouhadda

Shaïek

Roviras

et al. 2014

EURASIP J. Adv. Signal Process.

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In this paper, we introduce an analytical study of the impact of high-power amplifier (HPA) nonlinear distortion (NLD) on the bit error rate (BER) of multicarrier techniques. Two schemes of multicarrier modulations are considered in this work: the classical orthogonal frequency division multiplexing (OFDM) and the filter bank-based multicarrier using offset quadrature amplitude modulation (FBMC/OQAM), including different HPA models. According to Bussgang's theorem, the in-band NLD is modeled as a complex gain in addition to an independent noise term for a Gaussian input signal. The BER performance of OFDM and FBMC/OQAM modulations, transmitting over additive white Gaussian noise (AWGN) and Rayleigh fading channels, is theoretically investigated and compared to simulation results. For simple HPA models, such as the soft envelope limiter, it is easy to compute the BER theoretical expression. However, for other HPA models or for real measured HPA, BER derivation is generally intractable. In this paper, we propose a general method based on a polynomial fitting of the HPA characteristics and we give theoretical expressions for the BER for any HPA model.

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Section: Introductionmentioning

confidence: 99%

“…Other contributions [12,13] used the results presented in [11] to study the effect of HPA on multiple-input multiple-output (MIMO) transmit diversity systems. The impact of the HPA on out-of-band spectral regrowth was also studied for the OFDM system [14] as well as the FBMC/OQAM case [9,15].…”

Section: Introductionmentioning

confidence: 99%

Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

Bouhadda

Shaïek

Roviras

et al. 2014

EURASIP J. Adv. Signal Process.

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“…Moreover, the number of users supported in a DSA network can be increased by using Pseudo Carrier Interferometry (PCI) code sets, which have twice the number of codes compared with traditional CI code sets [29]. Discrete Fourier transform-spread OFDM (DFT-S-OFDM) was proposed to be one of the most promising modulation schemes for cognitive radio systems in [30]. Recently, DFT-S-OFDM has been proposed for 3GPP Long Term Evolution (LTE) systems [31].…”

Section: Spread Ofdmmentioning

confidence: 99%

Multicarrier Spread Spectrum Modulation Schemes and Efficient FFT Algorithms for Cognitive Radio Systems

Sundararajan

Govindaswamy

2014

Electronics

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Spread spectrum (SS) and multicarrier modulation (MCM) techniques are recognized as potential candidates for the design of underlay and interweave cognitive radio (CR) systems, respectively. Direct Sequence Code Division Multiple Access (DS-CDMA) is a spread spectrum technique generally used in underlay CR systems. Orthogonal Frequency Division Multiplexing (OFDM) is the basic MCM technique, primarily used in interweave CR systems. There are other MCM schemes derived from OFDM technique, like Non-Contiguous OFDM, Spread OFDM, and OFDM-OQAM, which are more suitable for CR systems. Multicarrier Spread Spectrum Modulation (MCSSM) schemes like MC-CDMA, MC-DS-CDMA and SS-MC-CDMA, combine DS-CDMA and OFDM techniques in order to improve the CR system performance and adaptability. This article gives a detailed survey of the various spread spectrum and multicarrier modulation schemes proposed in the literature. Fast Fourier Transform (FFT) plays a vital role in all the multicarrier modulation techniques. The FFT part of the modem can be used for spectrum sensing. The performance of the FFT operator plays a crucial role in the overall performance of the system. Since the cognitive radio is an adaptive system, the FFT operator must also be adaptive for various input/output values, in order to save energy and time taken for execution. This article also includes the various efficient FFT algorithms proposed in the literature, which are suitable for CR systems.

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“…On the other hand, it is obvious that most of the allocated spectrum experience low utilization [9]. There is various modulation techniques used with Cognitive Radio like: Phase Shift Keying (PSK), Frequency shift Keying (FSK), Orthogonal Frequency Division Multiplexing (OFDM) and types of OFDM [12][13][14][15][16]. We are giving here a brief introduction about each modulation technique.…”

Section: Modulation Techniquesmentioning

confidence: 99%

“…Although the channel equalization can be performed in a simple manner exploiting the CP, this method reduces the effective data rate of the system [15].…”

Section: Orthogonal Frequency Division Multiplexing (Ofdm) and It's Vmentioning

confidence: 99%

Assorted Facets of Physical Layer in Cognitive Radio: A Review

Verma¹,

Choudhary²,

Yarde³

2012

IJCA

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The intensification in the number of mobile subscribers over the preceding years leads to a situation of the Voice-oriented, data-oriented wireless telephony. It is now point in time to explore new demands and to find the new ways to broaden the mobile concepts. The Cognitive Radio (CR) is one of the essential steps that initiate the solution towards these problems. Then also there are lot of challenges associated to Cognitive Radio in the area of operational field and implementation in Real world. In this paper we tried to give the ideas about the voyage of Cognitive Radio from evolution to challenges experienced with respect to Physical Layer.

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Physical Layer Considerations for Cognitive Radio: Modulation Techniques

Cited by 12 publications

References 6 publications

Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

Multicarrier Spread Spectrum Modulation Schemes and Efficient FFT Algorithms for Cognitive Radio Systems

Assorted Facets of Physical Layer in Cognitive Radio: A Review

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