Design of FFT and IP Builder for OFDM Communication System

• Main Authors: Chi-Wen Shen, 沈積文
• Other Authors: Chyun-Shin Cheng
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/82390981250177929944

碩士 === 國立臺北科技大學 === 電腦通訊與控制研究所 === 91 === Orthogonal Frequency Division Multiplexing is a Spread Spectrum modulation technology. Today have many communication systems is using OFDM system, because it has the advantage of saving bandwidth, high data transmitting rate and reducing InterSymbol Interference effect, so it has become one of the most popular choices of transmission modulation technology. OFDM system uses Inverse Fast Fourier Transfer to make the signal orthogonal and combine each other, but the computing time of IFFT is very huge, thus the efficiency of IFFT has become the key point to the performance of OFDM system. The traditional radix-2 IFFT architecture will be idle on the waiting of input data. Therefore, in this thesis we propose a novel split FFT/IFFT architecture for OFDM to improve the traditional structure. It wills continuous calculating at idle time of original system. In the mean time, it also has the ability of parallel processing without data independence problem. When 4096-point IFFT our method can increase 16.6% efficiency. Furthermore, the proposed structure is fully scalable. Tender high-speed serial pipeline mode or chip-size-saving mode can be choice by user. We also refer the concept of SoC, creating an IP builder to improve new FFT hardware design to match the principle of reusability. With different input parameters, our IP builder can automatically generate a synthesizable VHDL code. Finally we use FPGA to verify this IP builder.