Closed-form Approximations of the PAPR Distribution for Multi-Carrier Modulation Systems

International audienceThe theoretical analysis of the Peak-to-Average Power Ratio (PAPR) distribution for an Orthogonal Frequency Division Multiplexing (OFDM) system, depends on the particular waveform considered in the modulation system. In this paper, we generalize this analysis by considering the Generalized Waveforms for Multi-Carrier (GWMC) modulation system based on any family of modulation functions, and we derive a general approximate expression for the Cumulative Distribution Function (CDF) of its continuous and discrete time PAPR. These equations allow us to directly find the expressions of the PAPR distribution for any particular family of modulation functions, and they can be applied to control the PAPR performance by choosing the appropriate functions

Closed-form approximations of the peak-to-average power ratio distribution for multi-carrier modulation and their applications

International audienceThe theoretical analysis of the peak-to-average power ratio (PAPR) distribution for an orthogonal frequency division multiplexing (OFDM) system, depends on the particular waveform considered in the modulation system. In this paper, we generalize this analysis by considering the generalized waveforms for multi-carrier (GWMC) modulation system based on any family of modulation functions, and we derive a general approximate expression for the cumulative distribution function (CDF) of its PAPR, for both finite and infinite integration time. These equations allow us to directly find the expressions of the PAPR distribution for any particular functions and characterize the behaviour of the PAPR distribution associated with different transmission and observation scenarios. In addition to that, a new approach to formulating the PAPR reduction problem as an optimization problem, is presented in this study

Peak-to-average power ratio analysis for OFDM-based mixed-numerology transmissions

In this paper, the probability distribution of the peak to average power ratio (PAPR) is analyzed for the mixed numerologies transmission based on orthogonal frequency division multiplexing (OFDM). State of the art theoretical analysis implicitly assumes continuous and symmetric frequency spectrum of OFDM signals. Thus, it is difficult to be applied to the mixed-numerology system due to its complication. By comprehensively considering system parameters, including numerology, bandwidth and power level of each subband, we propose a generic analytical distribution function of PAPR for continuous-time signals based on level-crossing theory. The proposed approach can be applied to both conventional single numerology and mixed-numerology systems. In addition, it also ensures the validity for the noncontinuous-OFDM (NC-OFDM). Given the derived distribution expression, we further investigate the effect of power allocation between different numerologies on PAPR. Simulations are presented and show the good match of the proposed theoretical results

An RF Carrier Bursting System using Partial Quantization Noise Cancellation

This paper introduces a novel method for bandpass cancellation of the quantization noise occurring in high efficiency, envelope pulsed transmitter architectures - or carrier bursting. An equivalent complex baseband model of the proposed system, including the Sigma Delta-modulator and cancellation signal generation, is developed. Analysis of the baseband model is performed, leading to analytical expressions of the power amplifier drain efficiency, assuming the use of an ideal class B power amplifier. These expressions are further used to study the impact of key system parameters, i.e. the compensation signal variance and clipping probability, on the class~B power amplifier drain efficiency and signal-to-noise ratio. The paper concludes with simulations followed by practical measurements in order to validate the functionality of the method and to evaluate the performance-trend predictions made by the theoretical framework in terms of efficiency and spectral purity

Enhanced Multicarrier Techniques for Professional Ad-Hoc and Cell-Based Communications (EMPhAtiC) Document Number D3.3 Reduction of PAPR and non linearities effects

Livrable d'un projet Européen EMPHATICLike other multicarrier modulation techniques, FBMC suffers from high peak-to-average power ratio (PAPR), impacting its performance in the presence of a nonlinear high power amplifier (HPA) in two ways. The first impact is an in-band distortion affecting the error rate performance of the link. The second impact is an out-of-band effect appearing as power spectral density (PSD) regrowth, making the coexistence between FBMC based broad-band Professional Mobile Radio (PMR) systems with existing narrowband systems difficult to achieve. This report addresses first the theoretical analysis of in-band HPA distortions in terms of Bit Error Rate. Also, the out-of band impact of HPA nonlinearities is studied in terms of PSD regrowth prediction. Furthermore, the problem of PAPR reduction is addressed along with some HPA linearization techniques and nonlinearity compensation approaches

Improving Spectral Efficiency While Reducing PAPR Using Faster-Than-Nyquist Multicarrier Signaling

Multicarrier modulations are widely used in mobile radio applications due to their adaptability to the time-frequency characteristics of the channel, thus enabling low-complexity equalization. However, their intrinsically high peak-to-average power ratio (PAPR) is a major drawback with regard to implementation issues (e.g., power amplification efficiency, regulatory constraints...). In this paper, we confirm that the PAPR can be decreased as the signaling density (i.e., spectral efficiency at fixed constellation size) increases, even in the case where symbols cannot be perfectly reconstructed using a linear system. In such a two-dimensional generalization of faster-than-Nyquist (FTN) systems, PAPR distribution models from the literature are confirmed by simulation results. Furthermore, for a fixed number of subcarriers, we show that a sufficient condition to yield the optimal PAPR distribution at the output of a critically sampled transmitter is to specify pulse shapes as tight frames. Finally, simulation are performed in the more realistic case of an oversampled transmitted signal

NOVEL OFDM SYSTEM BASED ON DUAL-TREE COMPLEX WAVELET TRANSFORM

The demand for higher and higher capacity in wireless networks, such as cellular, mobile and local area network etc, is driving the development of new signaling techniques with improved spectral and power efficiencies. At all stages of a transceiver, from the bandwidth efficiency of the modulation schemes through highly nonlinear power amplifier of the transmitters to the channel sharing between different users, the problems relating to power usage and spectrum are aplenty. In the coming future, orthogonal frequency division multiplexing (OFDM) technology promises to be a ready solution to achieving the high data capacity and better spectral efficiency in wireless communication systems by virtue of its well-known and desirable characteristics. Towards these ends, this dissertation investigates a novel OFDM system based on dual-tree complex wavelet transform (D