Fast calculation method and device of discrete Fourier transformation (DFT)/inverse discrete Fourier transform (IDFT)

Abstract

The invention discloses a fast calculation method of discrete Fourier transformation (DFT) / inverse discrete Fourier transform (IDFT). The rapid calculation method comprises the following steps of: carrying out zero fill on a bit sequence to be transformed to enable the sequence length after the zero fill to accord with the processing range of a fast Fourier transform (FFT) / inverse fast Fourier transform (IFFT) processor; carrying out FFT / IFFT calculation on the sequence after zero fill by utilizing the FFT / IFFT processor, and resampling time domain / frequency domain of an FFT / IFFT calculation result sequence according to a sampling position determined by the sequence lengths before and after the zero fill; and outputting the resampling result as a DFT / IDFT result sequence. The invention also discloses a fast calculation device of DFT / IDFT. By adopting the invention, the calculation complexity of DFT / IDFT can be reduced, and the calculation speed can be improved.

Description

technical field [0001] The present invention relates, in particular, to a fast calculation method and device for discrete Fourier transform (DFT) / inverse discrete Fourier transform (IDFT). Background technique [0002] In order to maintain a leading position in the field of mobile communications and grasp a new wave of technology, 3GPP initiated the research and standardization of 3G Long Term Evolution (LTE) at the end of 2004. In order to avoid the peak-to-average ratio (PAPR) brought by the multi-carrier system, and at the same time take advantage of the advantages of the multi-carrier system, the uplink system of the LTE system adopts a single-carrier DFT-OFDMA access method. figure 1 A block diagram of an LTE uplink transmission system is given. [0003] Such as figure 1 As shown, the number of resources (number of subcarriers) allocated to users each time in the uplink system is an integer multiple of 12, so FFT / IFFT cannot be used to directly complete the mapping an...

AI Technical Summary

Problems solved by technology

[0003] like figure 1 As shown, in the uplink system, the number of resources (subcarriers) allocated to users each time is an integer multiple of 12, so FFT / IFFT cannot be used directly to complete the mapping and demapping of subcarriers

At the same time, the computational complexity brought by the direct calculation of DFT / IDFT is unbearable, which makes the implementation complexity of the entire uplink system very high

In addition, when adopting pilot-aided channel estimation in OFDM system, it is necessary to use DFT / IDFT for interpolation or denoising processing based on domain transform, and it is also necessary to face the problem of computational complexity brought by direct calculation of DFT / IDFT, which leads to Denoising processing delay is very large

In short, in a system that needs to perform DFT / IDFT processing, due to the high computational complexity of directly calculating DFT / IDFT, the implementation complexity of the entire system increases, the delay is large, and the processing speed is low.

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