Performance Evaluation for WCDMA System under High-Speed Mobile Environments
Date Issued
2005
Date
2005
Author(s)
Lee, Chih-Hung
DOI
en-US
Abstract
As the demand of wireless communication services for high-speed mobile stations is increasing, the researches on the wireless mobile communication systems such as 3G WCDMA system utilized for high-speed trains (HST) will become more indispensable. In this thesis, we investigate the transmission performance for WCDMA system under the high-speed mobile rural area environments. Carrier synchronization and channel estimation are usually imperfect and the system performances are degraded due to the over Doppler shifting (ODS) problem. In order to improve the system performance, we propose a method, called the Doppler shift compensation (DSC), to overcome the ODS problem. We derive the mean square error (MSE) of the channel estimation by the conventional linear interpolation method and by our proposed approach. We found that our proposed approach has a tremendous improvement when the K factor is large. Based on the proposed receiver structure, we analyze the system performance for WCDMA system and compare it with that obtained by the conventional receiver in various high-Doppler multipath fading channels, where we have taken into account the effect of carrier recovery and imperfect channel estimation. Besides, we also demonstrate that no matter how large the Doppler transient is, the PLL can track the first finger well. However, when the change rate of Doppler frequency is very large, combining more fingers degrades the system performance for both the conventional and our proposed method.
Subjects
第三代行動通訊
寬頻分碼多工存取
無線通道特性
都
卜勒
偏移補償
暫態
3G
WCDMA
Wireless channel characteristics
High-speed mobile environment
Doppler shift compensation
Doppler transient
Type
thesis
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