在時間跳頻超寬頻系統中適用於盲目通道估測之事前機率反覆回授架構

Priori-Probability Iterative Feedback Structure for Blind Channel Estimation in TH-UWB Systems

田繼丞(Chi-Cheng Tien)

指導教授 ： 溫志宏

共同指導教授 ： 魏學文

國立暨南國際大學/科技學院/通訊工程研究所/碩士(2007年)

https://doi.org/10.6837/NCNU.2007.00250

摘要

本篇論文主要討論 在時間跳頻超寬頻系統下,利用回授架構改變接收端合成信號中位元0 和位元1的事前機率,讓盲目通道估測方法估測到越準確的通道.當傳送端傳送位元0和位元1的機率是任意產生時,若接收端合成信號的位元0和位元1的事前機率各是0.5的情況下,所估測到的通道會較差,則位元錯誤率也較高.若接收端合成信號的位元0和位元1的事前機率能隨著傳送端傳送位元0和位元1的機率改變,則能估測到較精確的通道,則位元錯誤率也較低.

我們提出的回授架構,是隨著傳送端傳送位元0和位元1的機率改變時,接收端合成信號的位元0和位元1的事前機率也會跟著改變.由於無線通訊廣泛應用在生活中, 所以我們必須考慮有多個使用者同時使用的情況,恰好我們使用時間跳頻超寬頻系統系統,可以經由改變每個使用者的時間跳頻碼而達到多個使用者同時使用的情況.我們所提出的回授架構能夠在單一使用者的情況下有不錯的結果,也期望能夠在多使用者的情況下有不錯的結果.

關鍵字

UWB ； Blind channel estimation ； TH-PPM

並列摘要

The main purpose of this essay is to discuss the blind channel estimate by using feedback structure to change the priori-probability of bit 0 and bit 1 in the receiver. When the disagreement between the transmitter and the received for probabilities of bit 0 and bit 1 increases, the estimated channel will be worse and the bit error rate will be higher. On the other hand, if the agreement between the transmitter and the received for probabilities of bit 0 and bit 1 increases, the estimated channel will be exact and the bit error rate will be low.

The feedback structure that we propose is useful when the probabilities of bit 0 and bit 1 in the transmitter change and the priori-probabilities of bit 0 and bit 1 of synthesized signal in the receiver change as well. Due to the wireless communication applied extensively in our life, we need to consider the case of multi-user use at the same time. We use the TH-UWB system to achieve the condition of multi-user usage at the same time by changing TH code from per user. On the other hand, the feedback structure we propose will have good performance in the case of signal user and we expect that we will also have good performance in the case of multi-user.

並列關鍵字

UWB ； Blind channel estimation ； TH-PPM

參考文獻

References

[1] Faranak Nekoogar, Ultra-Wideband Communications: Fundamentals and Applications. Prentice Hall, 2005.

[2] Xuemin Shen, Mohsen Guizani, Robert Caiming Qiu, and Tho Le-Ngoc, Ultra-Wideband Wireless Communications and Networks. Wiley, 2006.

[3] Kazimierz Siwiak and Debra McKeown, Ultra-Wideband Radio Technology. Wiley, 2004.

[4] Zhengdao Wang; Xiaofan Yang; “Blind channel estimation for ultra wide-band communications employing pulse position modulation,” Signal Processing Letters, IEEE , Volume 12, Issue 7, July 2005 Page(s):520 – 523.