基于編碼的OFDM系統的C語言設計與實

通信工程論文編號:TX399  論文字數:11190,頁數:34 
目錄
 
摘要 I
ABSTRACT II
第1章 引言 1
 1.1 背景 1
 1.11 OFDM簡介 1
 1.12 OFDM技術現狀及其發展 1
 1.2 研究內容 3
第2章 OFDM原理及其特點 4
 2.1 OFDM原理 4
 2.11 OFDM的基本模型 4
 2.1.2 快速傅里葉變換在OFDM中的應用 5
 2.2 OFDM系統特點 5
 2.2.1 OFDM的優點 5
 2.2.2 OFDM的缺點 6
第3章 OFDM系統的設計 8
 3.1 系統設計原理 8
 3.2 FFT及IFFT的實現 8
 3.3 信道的實現 9
 3.3.2 高斯信道的產生 9
 3.3.3 瑞利信道的產生 9
 3.3 程序流程圖 10
第4章 卷積碼編譯碼的設計 11
 4.1 卷積碼編碼 11
 4.2 維特比譯碼 12
 4.2.1 維特比譯碼概述 12
 4.2.2 維特比譯碼設計思路 13
第5章 仿真結果分析 15
 5.1 信道編碼及其性能分析 15
 5.2 循環前綴不同的情況下系統的性能分析 17
 5.3不同子信道數目下系統的性能 18
第6章 結束語 20
致謝 21
參考文獻 22
附錄 卷積碼源代碼 23

摘要

 在無線通信中對高速率和高質量的通信服務有所要求，OFDM技術因有高帶寬利用率和強抗多徑干擾的能力在近幾年得到廣泛的關注。OFDM是一種多載波調制技術，在20世紀60年代中期被提出，被用作發展有效的無線傳輸。OFDM技術被看作是一種高效的高速雙向無線數據傳輸技術。OFDM的主要思想是把信道分成若干正交的子信道把高速的數據流轉換成并行的低速數據流，調制到每個子信道進行傳輸。快速傅里葉算法和集成電路運算器在OFDM的幅度譜調制中發揮著重要作用。OFDM的基本應用包括DAB（Digital Audio Broadcasting，數字音頻廣播），WiMAX等等。
 本設計構基于C語言構建了一個完整的OFDM系統，調制和解調可以分別通過IFFT和FFT實現，通過加入卷積碼提高系統性能，最后統計數據，分別畫出在高斯信道和瑞利信道下的誤碼率曲線。
 
關鍵詞：OFDM，卷積碼，無線通信
 
ABSTRACT

In wireless communication, the high rate and high quality of communication service are required to be offered. And OFDM has the advantage of the high bandwidth efficiency and strong anti-multipath ability, so OFDM receives widespread attention in recent years. OFDM is described as a multi-carrier transmission technique which discovered in mid-1960s, and use for in developing effective wireless data transfer. It is recognized as an effective transmission technique for high speed bi-directional wireless data transfer. And the main idea of OFDM is that the Channel will be divided into several sub channels orthogonal, and then turn High-speed data signals into parallel low-speed data-flow, modulation in each of the sub channels on transmission. Fast Fourier transform (FFT) algorithm and integrated circuit implementation modulator play an influential role towards effective OFDM amplitude spectrum modulation. The basic use of the OFDM include DAB (Digital Audio Broadcasting), WiMAX and so on.
 The design constructs a complete OFDM system, and the basis property of OFDM. And the modulation or demodulation module can be achieved by IFFT and FFT respective. Add the Convolutional codes to improve the performance of the system. At last, by statistics the data, the curves of signal-to-noise ratio (SNR) - bit error in AWGN channel and Rayleigh channel is drawn.
 
Keyword：OFDM, Convolutional, Wireless communication