本篇論文在電腦中模擬了正交分頻多工(Orthogonal Frequency Division
Multiplexing, OFDM)以及兩種提高資料傳輸速率的方法，第一種是降低峰對平
均功率的比率，而其中降低的方法可區分為四個：削去(Clipping)、編碼
(Codding)、選擇性映射(Selective mapping, SLM)、部分傳輸序列(Partial
Transmit Sequences, PTS)，最後我選擇使用選擇性映射來使用，但因為選擇性
映射有一個很大的缺點就是浪費硬體空間，所以我會使用一種改良版本的選擇
性映射，稱作串聯的選擇性映射(Serial SLM)，第二種是位元和功率分配(bits
and power loading)，並與只有位元分配做比較，並且模擬改變資料調變形式對
於峰對平均功率的比率影響大小，可利用互補累積分布函數(Complementary
cumulative distribution function, CCDF)來觀察。
在實驗中架構了可見光通訊系統，因為微發光二極體的照度太小的關係，
尤其是藍光，一部分原因也是因為我們用的光感測器(PD)在藍光波長的敏感度
比較低，所以會使用綠光或者需要多幾顆微發光二極體使照度足夠接收端的光
感測器偵測到，並轉換為光電流進入示波器(Real time scope, RTS)觀察，之後
再盡量使傳輸距離拉開，使位元錯誤率達到前向錯誤更正( FEC)的門檻，當作
是可傳輸的最遠距離。
最後再用位元和功率加載來達到最大的資料傳輸速率。

This paper simulates OFDM and two methods to increase data rate in the
computer. The first method is reducing the peak to average power ratio(PAPR), and
the second is bit and power loading. Method of reducing PAPR can be divided into
four kinds: clipping, codding, selective mapping(SLM), partial transmit sequence
(PTS), finally I chose to use SLM. But SLM has a big drawback, wastes much
hardware space, I use a modified of SLM to improve that problem, called serial-
SLM. I compare with using both loading and only bits loading, and simulate the effect
of changing data modulation format to PAPR, which can be observed on
Complementary Cumulative Distribution Function(CCDF).
In the experiment, VLC is constructed. Because the illuminance of micro-LED is
too small, especially blue light, a part of reason is that our PD has worse sensitivity on
blue light, I need to use green lights or more micro-LEDs to make illumination
sufficient. Because of sufficient illumination, Photo diode can receive and convert it
into photocurrent and enter RTS to observe. Then, try to increase distance, so that bit
error rate(BER) would achieve the threshold of FEC, which is regarded as the longest
distance.
Finally, bit and power loading are used to achieve the maximum data rate.

中文摘要 .......................................................... I
ABSTRACT ...................................................... II
致謝 ............................................................ III
目錄 ............................................................. IV
圖目錄 ........................................................... VI
表目錄 ........................................................... IX
第一章 緒論.........................................................1
1.1 前言..........................................................1
1.2 研究目的與動機................................................6
1.3 論文架構......................................................7
第二章 元件特性與系統架構 ..........................................8
2.1 micro LED 發光原理............................................8
2.2 OFDM 的原理與調變..........................................10
2.3 Photo detector 的接收原理.......................................13
第三章 PAPR 的原理與改善方法......................................15
3.1 PAPR 的原理與統計方法.......................................15
3.2 PAPR 產生的缺點.............................................18
3.3 PAPR 四種常見改善方法.......................................19

V
3.3.1 Clipping..................................................19
3.3.2 Coding...................................................22
3.3.3 Selective mapping..........................................23
3.3.4 Partial Transmit Sequence....................................26
第四章 Serial Selective mapping.......................................30
4.1 Selective mapping 的優點與缺點.................................30
4.2 Serial Selective mapping 方法解析................................33
4.3 Serial Selective mapping 模擬結果................................35
第五章 bit loading 和 power loading..................................42
5.1 bit loading 和 power loading 的原理...............................42
5.2 bit loading 和 power loading 的算法...............................45
5.3 bit loading 和 power loading 模擬結果.............................48
第六章 實驗架構與結果討論..........................................50
6.1 可見光通訊實驗架構...........................................50
6.2 實驗結果及討論...............................................52
第七章 結論........................................................61
參考文獻...........................................................62

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