Evaluation of Performance Improvement Capabilities of PAPR-reducing Methods
Wireless Personal Communications: An International Journal
IEEE Communications Letters
On Level-Crossing Excursions of Gaussian Low-Pass Random Processes
IEEE Transactions on Signal Processing - Part II
IEEE Transactions on Wireless Communications
Improvement of power efficiency of HPA by the PAPR reduction and predistortion
IEEE Transactions on Consumer Electronics
Using Walsh code selection to reduce the power variance of band-limited forward-link CDMA waveforms
IEEE Journal on Selected Areas in Communications
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This paper deals with the nonlinear distortion (NLD) effects of high power amplifiers (HPAs) on direct sequence-code division multiple access systems. Such a distortion drastically degrades the system performance in terms of bit error rate (BER) degradation and spectral regrowth. Much effort has been conducted to minimize NLD. A key requirement to do so is to define a certain measure for the HPA nonlinearity, which when reduced often allows NLD to also be reduced. Several measures were proposed such as peak-to-average power ratio, instantaneous power variance, and cubic metric. In this paper, we show that such measures are not closely related to NLD and their reduction does not always lead to optimum performance. Hence, we introduce an efficient measure, namely, nonlinearity severity (NLS), to characterize NLD effects, as an alternative to the existing measures. The NLS is characterized by having direct link to the system performance as it is formulated based on the signal characteristics contributing to BER performance and spectral regrowth. Additionally, a major advantage of the NLS measure is that it is linked to the IBO level allowing the possibility of improving performance at all IBO levels of interest.