正交分頻多工傳接機軟體無線平台模組共用設計與實現研究

Implementation and Design of OFDM transceiver based on SDR platform using FPGA

蔡豐宇(Fong-Yu Tsai)

指導教授 ： 馬杰

元智大學/電機通訊學院/通訊工程學系/碩士(2012年)

摘要

正交分頻多工(Orthogonal Frequency-Division Multiplexing , OFDM)系統具備高速率傳輸資料的能力，並且能有效對抗頻率選擇性通道衰減，已被廣泛應用於無線通訊系統。本篇論文採用領航訊號通道估測法應用於單輸入單輸出(Single Input Single Output, SISO)的特定短程通訊系統(Dedicated Short Range Communications, DSRC)中，並加入數位波束成型(Digital Beamforming, DBF)智慧型天線技術，改善OFDM系統之性能。採用領航訊號通道估測法可降低多路徑衰減通道之位元錯誤率(Bit Error Rate, BER)，而數位波束成型器可提升系統的傳輸範圍。同時根據IEEE 802.11p規格標準，設計OFDM系統傳接機，採用數位訊號處理器(Digital Signal Processor, DSP)與現場可程式化邏輯閘陣列(Field Programmable Gate Array, FPGA)來實現DSRC基頻傳接機，驗證其功能，並設計軟體無線電傳接架構，共用傳送機與接收機的模組，探討其硬體資源與傳接機性能。
由於各種天線模式之演算法涉及角度與三角函數的運算，無法被FPGA處理器支援實現，因此我們採用坐標旋轉數位計算(Coordinate Rotation Digital Computer, CORDIC)演算法，應用於DBF模組與CFO模組，改善FPGA處理運算的效率。研究項目包含：
(1) 應用CORDIC演算法，設計通道估測與補償之電路模組。
(2) 設計單輸入單輸出與數位波束成型之電路模組。
(3) 以FPGA處理器實現與測試DBF天線模式與OFDM傳接機平台之性能。
(4) 整合傳送接與接收機，設計軟體無線電共用模組之機制，藉以降低FPGA資源。

關鍵字

正交分頻多工 ； 軟體無線平台 ； 特定短程通訊系統

並列摘要

Following the IEEE802.11p physical layer standard, this thesis designs the Orthogonal Frequency-Division Multiplexing (OFDM) transceiver on the DSP/FPGA platform and uses Digital Beamforming (DBF) to enhance the performance of the OFDM system. Because of many antenna mode algorithms require the evaluation of phase angle and trigonometric, which are not supported by FPGA ModelSim’s library, the Coordinate Rotation Digital Computer (CORDIC) algorithm is employed to improve the computing efficiency.
The research items include: applying the CORDIC algorithm to design the circuit modules of DBF and CFO; designing single-input-single-output (SISO) and DBF circuit modules based on SDR platform; designing the common modules mechanism of SDR OFDM transceiver; FPGA resource comparison between OFDM transceiver and OFDM transceiver based on SDR platform. Experimental results demonstrate that the resource of SDR platform is better than the original platform.

並列關鍵字

OFDM ； DSRC ； SDR

參考文獻

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[8] Clive Max Maxfield, “The Design Warrior’s Guide to FPGAs,” Newnes.