Paper Info
Title
MAP channel estimation for Alamouti-based cooperative networks
Abstract
In this paper, we consider a cooperative network with one source, one destination and two relays to bring cooperative diversity. We assume the link between the source and the destination is so bad that we do not consider it. We propose a Decode-And-Forward (DAF) strategy based on the Alamouti space-time (ST) code. The two relays must recover the transmitted sequence and forward it to the destination. We consider fast time varying channels between the cooperative users and the destination and our objective is to estimate these two channels in order to recover the information sequence at the destination. We propose a data-aided decision-directed Maximum A Posteriori (MAP) iterative channel estimation algorithm. It can profit from an optimum initialization by means of the MAP data- aided channel estimation. Besides, we adapt this iterative receiver to the case where the destination is equipped with two receive antennas to bring more diversity. The validity of the proposed algorithms is highlighted by simulation results. two links seen at the destination are characterized by different Doppler spreads and each relay must recover the transmitted sequence before forwarding it to the destination. We derive a data-aided decision-directed algorithm which performs an iterative channel estimation according to the MAP criterion, using the Expectation-Maximization (EM) algorithm. This al- gorithm will be derived for the estimation of the two links seen at the destination but the formulation for the link source-relay is straightforward. Besides, we adapt this iterative receiver for a cooperative network which considers a similar DAF protocol but with two receive antennas at the destination. The rest of the paper is organized as follows. In section II, we introduce the system model with one receive antenna at the destination. In section III, we develop a convenient representation of the two discrete multi-path fading channels seen at the destination. In section IV, we derive the iterative receiver based on a data- aided decision-directed MAP channel estimation algorithm and give some simulations results to highlight the validity of the algorithm. In section V, we adapt this iterative receiver for the case of two receive antennas at the destination.
Year
DOI
Venue
2008
10.1109/PIMRC.2008.4699833
Cannes
Keywords
Field
DocType
channel estimation,diversity reception,maximum likelihood estimation,receivers,relays,space-time codes,Alamouti space-time code,Alamouti-based cooperative networks,cooperative diversity,data-aided channel estimation,decode-and-forward strategy,iterative receiver,maximum a posteriori iterative channel estimation,relays
Computer science,Cooperative diversity,Maximum likelihood,Communication channel,Real-time computing,Maximum a posteriori estimation,Initialization
Conference
ISBN
Citations 
PageRank 
978-1-4244-2644-7
0
0.34
References 
Authors
5
2
Name
Order
Citations
PageRank
Kammoun, I.130.85
Mohamed Siala2248.48