採單一時隙以最大概似估算法作正交多頻分工之載頻追蹤

A Maximum-Likelihood Based Frequency Tracking Technique for OFDM using A Single Time Slot Pilot Sample

鄭搏強(Po-Chiang Cheng)

指導教授 ： 嚴雨田

淡江大學/工學院/電機工程學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00210

摘要

此篇論文在處理良好的頻率追蹤在正交分頻多工系統裡。無論是在時域或在頻域中去執行頻率偏移量的估測，執行良好的頻率追蹤通常是使用多個或一個完整的正交多頻分工的試驗區塊或數據訓練。這裡我們所使用的方法是採用單一樣品，而不是採用多個樣品，這問題可以大大的簡化在所收到之頻域中正交分頻多工的區塊資料，且仍然達到合理的追蹤性能。這證明我們的單一樣品的最大似頻率偏移估測量可以是不偏不移的而且均方誤差將更接近CRB，當訊號雜訊比增加。

關鍵字

正交分頻多工系統 ； 最大概似估計法 ； 最小線性均方誤差 ； 通道估計

並列摘要

This thesis deals with fine frequency tracking in orthogonal frequency division multiplexing (OFDM) systems. The usual practice for fine frequency tracking is to use multiple or an entire OFDM block of pilot or training data, either in the time domain or in the frequency domain to perform frequency offset estimation. Here we show that, instead of the elaborate approach of using multiple pilot samples, the problem can be greatly simplified by using only a single pilot sample from a selected time slot in the received time-domain OFDM block to still achieve reasonable tracking performance. It is proven that our single sample ML frequency offset estimator tends to be unbiased and its mean square error (MSE) will approach the Cramer-Rao bound (CRB) as SNR is increased.

並列關鍵字

Orthogonal frequency division multiplexing (OFDM) ； maximum likelihood estimation ； linear minimum mean square error (LMMSE) ； Cramer-Rao bound (CRB) ； channel estimation

參考文獻

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