On Channel Estimation for Space-Time Trellis Coded OFDM Systems

Sang-Mun LEE  Hyung-Jin CHOI  

IEICE TRANSACTIONS on Communications   Vol.E85-B    No.11    pp.2353-2361
Publication Date: 2002/11/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fundamental Theories
OFDM,  transmitter diversity,  space-time trellis code,  channel estimation,  

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In transmitter diversity, the received signal is the superposition of signals transmitted from transmitter antennas. Thus, the separation of channel characteristics corresponding to each transmitter antennas from these signals is very important. The conventional channel estimation scheme tends to show higher computational complexity for larger channel delay profile. To reduce this computational complexity, significant-tap-catching method has been proposed. However, there is still a burden of complexity for data transmission mode. Reference [14] has shown how to reduce the complexity for data transmission mode in system with constant modulus modulation. However, this method can't reduce the complexity required for multi-level signals such as QAM. In this paper, we propose an efficient channel estimation scheme for OFDM systems with transmitter diversity using space-time trellis coding. The computational complexity of the proposed scheme is independent of channel delay profile. Also, compared with the conventional scheme, the complexity of the proposed scheme is not related to modulation methods including multi-level signals such as QAM. The performance of the proposed scheme is evaluated by computer simulation in various multipath fading environments.