Maximum-Likelihood Detection of Orthogonal Space-Time Block Coded OFDM in Unknown Block Fading Channels

For orthogonal space-time block coded orthogonal frequency division multiplexing (OSTBC-OFDM) systems, many of the existing blind detection and channel estimation methods rely on the assumption that the channel is static for many OSTBC-OFDM blocks. This paper considers the blind (semiblind) maximum-likelihood (ML) detection problem of OSTBC-OFDM with a single OSTBC-OFDM block only. The merit of such an investigation is the ability to accommodate channels with shorter coherence time. We examine both the implementation and identifiability issues, with a focus on BPSK or QPSK constellations. In the implementation, we propose reduced-complexity detection schemes using subchannel grouping. In the identifiability analysis, we show that the proposed schemes can ensure a probability one identifiability condition using very few number of pilots. For example, the proposed semiblind detection scheme only requires a single pilot code for unique data identification; while the conventional pilot-bas...

• Type: Journal
• Year: 2008
• Where: TSP
• Authors: Tsung-Hui Chang, Wing-Kin Ma, Chong-Yung Chi
• Keywords: Channel Estimation, Detection, Ostbc-ofdm Block, TSP 2008