正交分頻多工系統中使用子空間方法估測載波頻率偏移

Carrier Frequency Offset Estimation for OFDM Systems Using Subspace-Based Methods

戴尉任(Wei-Jen Tai)

指導教授 ： 馮世邁

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00978

摘要

無資料

關鍵字

正交分頻多工系統 ； 盲載波頻率偏移估測 ； 子空間

並列摘要

The OFDM system has been a widely adopted technique for both wired and wireless transmission. It is well-known that one of the most important problem for the OFDM systems is the carrier frequency mismatch between the transmitter and the receiver. The frequency mismatch is called as carrier frequency o set (CFO). The CFO would destroy the subcarrier orthogonality of OFDM systems. As a result the performance of OFDM systems will degrade severely if CFO is not properly compensated. Therefore, It is important to precisely estimate and compensate CFO for OFDM systems.
In this thesis, the effect of CFO in OFDM systems is presented first, and then estimations and compensations of CFO are considered. We propose a simple modification for existing CFO estimation methods. It is a semi-blind method since we need to know the position of data subcarriers. The proposed method is simple but offer significant performance gain. In simulation results, we show that the performance is improved by using the proposed modification.
We also propose another semi-blind method which is low-complexity since it does not need any SVD or EVD operations. It is shown by simulation results that the performance of the proposed low-complexity method is the same as the existing method which needs SVD operation. Our methods do not take any training sequences or pilots, so we can improve the bandwidth efficiency.

並列關鍵字

OFDM ； Blind carrier frequency offset estimation ； Subspace

參考文獻

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