Title :
The effect of out-of-synchronization on channel estimation and joint detection in downlink TD-SCDMA systems
Author_Institution :
Wireless Commun. Group, Philips Res. East Asia, Shanghai, China
Abstract :
In this paper, the effect of out-of-synchronization on channel estimation and then joint detection in downlink TD-SCDMA has been analyzed from both theory and simulations when different midambles are assigned to different user equipments (UE). The analysis shows that the maximum likelihood (ML) channel estimation using the specially designed midambles implemented with fast Fourier transform (FFT) will result in a circular shift of the actual channel impulse response (CIR) when downlink channel is in out-of-synchronization, and based on this, the shift deviation of downlink synchronization point along different direction of level axis (left or right) during some periods will cause quite different impact on joint detection.
Keywords :
3G mobile communication; channel estimation; code division multiple access; fast Fourier transforms; radio links; signal detection; synchronisation; time division multiple access; transient response; channel estimation; channel impulse response; downlink TD-SCDMA systems; fast Fourier transform; joint detection; maximum likelihood channel estimation; out-of-synchronization; user equipments; Analytical models; Channel estimation; Downlink; Fading; Fast Fourier transforms; Interference; Maximum likelihood detection; Maximum likelihood estimation; Multiaccess communication; Time division synchronous code division multiple access;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2003. PIMRC 2003. 14th IEEE Proceedings on
Print_ISBN :
0-7803-7822-9
DOI :
10.1109/PIMRC.2003.1264420
