Novel power back-off amount metric system and method based on out-of-band cubic metric (OCM)

Abstract

The invention discloses a novel power back-off amount metric system and method based on out-of-band cubic metric (OCM). The system comprises a serial / parallel conversion module, an IFFT conversion module, a parallel / serial conversion module, a signal OCM calculation module and a power back-off amount calculation module. The serial / parallel conversion module is connected with the input end of the IFFT conversion module, one output end of the IFFT conversion module is connected with a power amplifier sequentially through the signal OCM calculation module and the power back-off amount calculation module. The method includes the steps that the average power value Pav of an original OFDM signal is calculated; the out-of-band radiation average power value POB of the OFDM signal is calculated; the OCM is calculated; the power back-off (PBO) amount is calculated. The power back-off amount is predicated by the adoption of the out-of-band radiation average power of the OFDM signal and the average power of an original signal, an out-of-band part of third-order output is directly used for predicating out-of-band radiation, and compared with a traditional PAPR method and a traditional CM method, the power back-off amount needed by the power amplifier (PA) can be predicated more accurately.

Description

technical field [0001] The invention relates to the field of power backoff measurement, in particular to a novel power backoff measurement system and method based on out-of-band cubic metric OCM. Background technique [0002] OFDM technology is a multi-carrier digital modulation technology. OFDM signals are superimposed by multiple independent sub-carrier signals. Therefore, when the number of sub-carriers increases to a relatively large number, the OFDM time-domain signal will approximate a complex Gaussian random process, so the fluctuation of its signal envelope is much larger than that of a single-carrier system. The large fluctuation of the signal envelope requires a large linear range of the power amplifier (PA), otherwise, the signal enters the nonlinear region, which will cause serious out-of-band radiation (OBR), resulting in phase adjacent channel interference. However, due to the nonlinear characteristics of the PA, the power amplifier is required to have a larg...

AI Technical Summary

Problems solved by technology

[0014] ① OBR is caused by third-order nonlinearity, and the PAPR algorithm only considers the peak power, which cannot accurately represent OBR;

[0015] ② The third-order nonlinearity not only causes OBR, but also causes in-band distortion

In fact, the CM measurement method uses the third-order nonlinear distortion signal falling into the in-band and out-of-band parts to predict the amount of power backoff, so the CM algorithm is not accurate enough

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