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【应用笔记】3GPP长期演进的1536点快速傅里叶变换(FFT1536-Point FFT for 3GPP Long Term Evolution)
3GPP长期演进(Long Term Evolution,LTE)是一个不断发展中的项目。该项目可以提高通用移动通信系统(Universal Mobile Telecommunications System,UMTS)标准来应对移动电话的未来需求。其主要目标包括较高的数据速率、改进频谱效率、提升覆盖范围和缩短延时。该参考设计实现了一个1536点FFT作为独立的核。
3GPP Long Term Evolution (LTE) is an ongoing project to improve the
universal mobile telecommunication system (UMTS) standard to handle
future requirements of mobile phones. The main targets include higher
data rates, improved spectrum efficiency, improved coverage, and
reduced latency.
In an LTE project, the system must support variable transmission
bandwidths, including 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, 15 MHz,
and 20 MHz. Each transmission bandwidth corresponds to a fast Fourier
transform (FFT) size of 128, 256, 512, 1024, 1536, and 2048 points,
respectively.
This reference design implements a 1536-point FFT as a stand-alone core.
This core satisfies the FFT size requirement of 1536 points for a
bandwidth of 15 MHz in an LTE project. To meet the other FFT size
requirement of two’s/four’s exponent for the rest of the bandwidth, refer
to the Altera® FFT IP MegaCore® function, which is a parameterizable
core that supports sizes from 32 to 16K points with radix-2 and radix-4
computations. Among these FFT sizes, most of the calculations are done
with a radix-2/4 engine. The 1536-point discrete Fourier transform (DFT)
is the only one using radix-3 in addition to radix-2 and radix-4
computation. In other words, Altera offers complete solutions to meet all
FFT sizes required in the LTE project.an480.pdf