使用FFT之MC-CDMA系統於UWB通道下之效能分析

Performance Analysis of FFT-based MC-CDMA System in UWB Channel

詹政道(Cheng-Tao Chan)

指導教授 ： 呂振森

國立臺北科技大學/機電學院/電機工程系所/碩士(2006年)

摘要

在本篇論文中，首先對超寬頻無線通道與正交分頻多工調變做概述。在無線傳輸中，超寬頻系統具有使用極大之頻寬，且發射訊號有短距離、低功率消耗與高速率之傳輸特性。近年來，大部分的研究與發展著重於在直序式超寬頻與多頻帶超寬頻系統。本論文主要是探討了一個基於傅立葉轉換之多載波分碼多工系統在超寬頻通道之效能。分碼多工技術主要是藉由指定不同的展頻碼給各個使用者，讓多使用者可同時在同一通道中傳輸訊號。而多載波分碼多工繼承了多載波調變之優良抗頻率選擇性通道與符號間干擾之優點。為了分析基於傅立葉轉換之多載波分碼多工於超寬頻通道之效能，我們以理論推導其系統位元錯誤率公式，並建立一組依IEEE 802.15所制定之4類型通道模擬程式。最後藉由電腦模擬分析其中之因果關係。

關鍵字

正交分頻多工 ； 超寬頻 ； 快速傅立葉轉換 ； 多載波分碼多工

並列摘要

In this thesis, an overview of the UWB indoor wireless channel and OFDM is presented first. UWB radios are characterized by the extremely wide bandwidth of their radiated signals with the advantages of short range, low power consumption, high data rate and so on. In the recent years, most researches and developments were focused on DS-UWB and MB-UWB. In this thesis, an alternative system based on MC-CDMA is proposed for analyzing in UWB channels. CMDA is a multiplexing technique where a number of users simultaneously and asynchronously access a channel by modulating and spreading their information-bearing signals with pre-assigned signature sequences. MC-CDMA inherits the advantages of Multi-Carrier Modulation, so it’s robust against frequency selective fading and ISI. To exhibit the system performance of FFT based MC-CDMA in UWB channel, the bit error rate formula for this system is derived and a group of programs is constructed with four types of UWB channel model defined by IEEE 802.15. Then we compare these simulation results and analyze them.

並列關鍵字

OFDM ； UWB ； FFT ； MC-CDMA

參考文獻

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