A New Approach for Evaluating Clipping Distortion in DS-CDMA Systems

WANG, J.

doi:10.1093/ietcom/e88-b.2.792

Cited by 5 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clipping has been thought to introduce error. But it actually depends on careful selection of clipping level [8].…”

Section: Proposed Solutionmentioning

confidence: 99%

High peak to average ratio solution in OFDM of 4G mobile systems

Qaddour

2006

Proceedings of the 2006 International Conference on Wireless Communications and Mobile Computing

View full text Add to dashboard Cite

The advent of 4G wireless systems has created many research opportunities. The expectations from 4G are high in terms of data rates, spectral efficiency, mobility and integration. Orthogonal Frequency Division Multiplexing (OFDM) is proving to be a possible multiple access technology to be used in 4G. But OFDM comes with its own challenges like high Peak to Average Ratio, linearity concerns and phase noise. This paper proposes a solution to reduce Peak to Average Ratio by clipping method. MATLAB was used to generate the OFDM signal to prove that clipping does reduce Peak to Average Ratio.

show abstract

“…Clipping has been thought to introduce error. But it actually depends on careful selection of clipping level [8].…”

Section: Proposed Solutionmentioning

confidence: 99%

High peak to average ratio solution in OFDM of 4G mobile systems

Qaddour

2006

Proceedings of the 2006 International Conference on Wireless Communications and Mobile Computing

View full text Add to dashboard Cite

show abstract

New theoretical framework for OFDM/CDMA systems with peak-limited nonlinearities

et al. 2007

View full text Add to dashboard Cite

A new theoretical framework for the evaluation of the in-band nonlinear distortion effects on the performance of OFDM systems is presented. In contrast to previous works that approximate the nonlinear noise as a Gaussian additive random process, the new framework is based on the properties of the large deviations of a stationary Gaussian process and shot noise theories, which can evaluate the performance of the OFDM system with high accuracy, especially at realistic scenarios where the Gaussian approximation of the nonlinear noise is no longer valid. The approach can be used to evaluate many communication systems with peak-limited nonlinearities and high PAPR, such as the downlink performance analysis of large capacity DS-CDMA systems.OFDM, CDMA, nonlinearities, impulse noise OFDM is a promising candidate for achieving high data rate transmission in wireless environment and is widely employed in communication systems. Since an OFDM signal is the sum of several statistically independent random subcarriers, its baseband in-phase/quadrature (I/Q) components can be approximately represented as a Gaussian process with Rayleigh envelope distribution and uniform phase distribution invoking the Central Limit Theorem [ ] 1 . Simulation results show that the Gaussian approximation is very realistic for most of the practical systems of interest with a sufficiently large number of subcarriers. One of the major drawbacks of a nearly Gaussian OFDM waveform is a greatly variable envelope or high peak-to-average power ratio (PAPR) that makes it particularly sensitive to nonlinear distortions, such as analog-to-digital (A/D) converters, IFFT/FFT processors with finite word length, RF high power amplifiers (HPA), etc., which will cause both in-band and out-of-band distortion. It has been shown that the out-of-band distortion can be removed using a simple filter without adding any distortion to the signal [ ] 2 . Recently, several different methods have been derived for analysis of in-band distortion of OFDM systems. The effect of the distortion can be modeled as attenuation of the signal and generation of a nonlinear additive noise [ ] 3 . This nonlinear noise

show abstract

4G Mobile Communication Systems: Turns, Trends and Transition

Govil

2007

2007 International Conference on Convergence Information Technology (ICCIT 2007)

View full text Add to dashboard Cite

A New Approach for Evaluating Clipping Distortion in DS-CDMA Systems

Cited by 5 publications

References 0 publications

High peak to average ratio solution in OFDM of 4G mobile systems

High peak to average ratio solution in OFDM of 4G mobile systems

New theoretical framework for OFDM/CDMA systems with peak-limited nonlinearities

4G Mobile Communication Systems: Turns, Trends and Transition

Contact Info

Product

Resources

About