This paper describes a crest factor reduction （CFR） method that reduces peaks in the time domain by modifying selected data subcarriers within an OFDM signal. The data subcarriers selected for modification vary with...This paper describes a crest factor reduction （CFR） method that reduces peaks in the time domain by modifying selected data subcarriers within an OFDM signal. The data subcarriers selected for modification vary with each symbol interval and are limited to those subcarriers whose aata elements are mapped onto the outer boundary of the constellation. In the proposed method, a set of peaks are identified within an OFDM symbol interval. Data subcarriers whose data element has a positive or negative correlation with the set peak are selected. For a subcarrier with an outer element and a significant positive correlation, a bit error （reversal） is intentionally introduced. This moves the data element to the opposite side of the constellation. Outer elements on negatively-correlatea subcarriers are increased in magnitude along the real or imaginary axis. Experimental results show that selecting the correct subcarriers for bit reversals and outward enhancements reduces the peak-to-average power ratio （PAPR） of the OFDM signal to a target value and limits in-band degradation measured by bit error rate （BER） and error vector magnitude （EVM）.展开更多
A segmentation multi-dimensional crest factor reduction （SMD-CFR） algorithm is proposed for multi-service supporting digital radio over fibre （DRoF） system. Benefit from segmentation dynamic clipping threshold and...A segmentation multi-dimensional crest factor reduction （SMD-CFR） algorithm is proposed for multi-service supporting digital radio over fibre （DRoF） system. Benefit from segmentation dynamic clipping threshold and clipping factor got basing on characteristics of all service bands, the SMD-CFR is able to get better peak clipping and peak to average power ratio （PAPR） reduction for multi-band combined signal. Simulation results show that SMD-CFR gets more than 2.3 reduction in PAPR for two-bands combined signal of long term evolution （LTE） , which is much better than traditional one dimensional （1D）-CFR. Meanwhile, for 64-quadrature amplitude modulation （QAM） modulation and demodulation link, it has very small effect on bit error rate （BER） and error vector magnitude （EVM） , which are controlled less than 0. 1% and 0.2% respectively. For hardware experiment, SMD-CFR obtains 4.5% increase in drain efficiency and about 4 dBc increase in adjacent channel leakage ratio （ACLR）. These are very significant for the wide band power amplifier （PA） in multi-service supporting DRoF system.展开更多
文摘This paper describes a crest factor reduction （CFR） method that reduces peaks in the time domain by modifying selected data subcarriers within an OFDM signal. The data subcarriers selected for modification vary with each symbol interval and are limited to those subcarriers whose aata elements are mapped onto the outer boundary of the constellation. In the proposed method, a set of peaks are identified within an OFDM symbol interval. Data subcarriers whose data element has a positive or negative correlation with the set peak are selected. For a subcarrier with an outer element and a significant positive correlation, a bit error （reversal） is intentionally introduced. This moves the data element to the opposite side of the constellation. Outer elements on negatively-correlatea subcarriers are increased in magnitude along the real or imaginary axis. Experimental results show that selecting the correct subcarriers for bit reversals and outward enhancements reduces the peak-to-average power ratio （PAPR） of the OFDM signal to a target value and limits in-band degradation measured by bit error rate （BER） and error vector magnitude （EVM）.
基金supported by the projects of ‘Smart in-building Wireless System using Flexible Digital Transmission Technology(SWIFT)’‘Research on in-building Signal Coverage System of Mobile IOT Based on Cloud’
文摘A segmentation multi-dimensional crest factor reduction （SMD-CFR） algorithm is proposed for multi-service supporting digital radio over fibre （DRoF） system. Benefit from segmentation dynamic clipping threshold and clipping factor got basing on characteristics of all service bands, the SMD-CFR is able to get better peak clipping and peak to average power ratio （PAPR） reduction for multi-band combined signal. Simulation results show that SMD-CFR gets more than 2.3 reduction in PAPR for two-bands combined signal of long term evolution （LTE） , which is much better than traditional one dimensional （1D）-CFR. Meanwhile, for 64-quadrature amplitude modulation （QAM） modulation and demodulation link, it has very small effect on bit error rate （BER） and error vector magnitude （EVM） , which are controlled less than 0. 1% and 0.2% respectively. For hardware experiment, SMD-CFR obtains 4.5% increase in drain efficiency and about 4 dBc increase in adjacent channel leakage ratio （ACLR）. These are very significant for the wide band power amplifier （PA） in multi-service supporting DRoF system.
