文档介绍：Iterative Receivers for Space-time Block Coded OFDM Systems
in Dispersive Fading Channels
Ben Lu, Xiaodong Wang Ye (Geoffrey) Li
Department of Electrical Engineering School of Electrical puter Engineering
Texas A&M University ia Institute of Technology
College Station, TX 77843. Atlanta, GA 30332.
 
benlu,wangx ¡ ***@ ******@
Abstract – We consider the design of iterative receivers for drawback to any decision feedback system, when the decisions are
space-time block coded orthogonal frequency-division multiplex- not accurate (., in very fast fading channels), the receivers in
ing (STBC-OFDM) systems in unknown wireless dispersive fad- [5, 6] show error floors. In this paper, we approach the problem
ing channels, with or without outer channel coding. First, we of receiver design without CSI by using iterative techniques, in-
propose a maximum-likelihood (ML) receiver for STBC-OFDM cluding the expectation-maximization (EM) algorithm [7] and the
systems based on the expectation-maximization (EM) algorithm. Turbo processing method [3]. In [8], EM receivers are studied
By assuming that the fading processes remain constant over the for sequence estimation in uncoded and coded systems. More re-
duration of one STBC code word, and by exploiting the orthog- cently, in [9, 10], a receiver employing the EM algorithm, which
onality property of