適用於多輸入多輸出正交分頻多工 Wi-MAX 系統之可變長度快速傅立葉轉換

在這篇論文，我們介紹一個可以應用於 Wi-MAX 系統中的可變長度快速傅立葉轉換。這個可變長度快速傅立葉轉換可以提供許多快速傅立葉轉換的長度及多天線傳輸。這個2048/1024/512/128-point可變長度快速傅立葉轉換是以 radix-2 及 radix-2^3 快速傅立葉轉換演算法。我們也提出一個記憶體分享的方法去減少記憶體的使用。這個方法比較於R2SDF的方法可以減少ROM表格大小從1023N/1024到N/4 ，N為快速傅立葉轉換的長度。此外，我們使用快速傅立葉轉換演算法使得複數乘法器的數量減少並且也使用修正的複數乘法器使的所使用的邏輯閘數比較少。如此功率消耗也能更加節省。我們所提出的可變長度快速傅立葉轉換是使用台積電 0.18um CMOS製程所製造，晶片的面積為25mm^2 。當處理器操作於頻率40MHz時所需的功率為181 mW。

關鍵字

多輸入多輸出；正交分頻多工；快速傅立葉轉換； WiAMX

並列摘要

In this thesis, we present a variable FFT that it support multiple FFT size and multiple antennas for Wi-MAX systems. The 2048/1024/512/128-point variable FFT is based on radix-2 and radix-2^3 FFT algorithm. We propose a memory sharing method to reduce the memory size. This method can reduce the ROM table size from 1023N/1024 to N/4, where N is the FFT size, compared with R2SDF. Furthermore, we use the FFT algorithm to reduce the number of complex multipliers, and the modified complex multiplier leads to a smaller gate count. Thus, the power consumption can be to reduced as well. The proposed variable FFT is fabricated using a TSMC 0.18um CMOS technology with chip area 25 mm^2. The average dynamic power consumption is 181 mW at 40 MHz operating frequency.

並列關鍵字

MIMO ； OFDM ； FFT ； WiMAX

參考文獻

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[6] B. M. Baas, “An approach to low power, high performance, fast Fourier

[7] C. P. Hsu, “Design of Fast Fourier Transform Processor in DVB-T Inner

國際替代計量

適用於多輸入多輸出正交分頻多工 Wi-MAX 系統之可變長度快速傅立葉轉換

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