1 Department of Electronic Systems, The Faculty of Engineering and Science (ENG), Aalborg University, VBN2 Navigation and Communications, The Faculty of Engineering and Science (ENG), Aalborg University, VBN3 The Faculty of Engineering and Science (TECH), Aalborg University, VBN4 Technical University of Vienna5 Wireless Communication Networks, The Faculty of Engineering and Science (ENG), Aalborg University, VBN
We present a joint message passing approach that combines belief propagation and the mean field approximation. Our analysis is based on the region-based free energy approximation method proposed by Yedidia et al. We show that the message passing fixed-point equations obtained with this combination correspond to stationary points of a constrained region-based free energy approximation. Moreover, we present a convergent implementation of these message passing fixed-point equations provided that the underlying factor graph fulfills certain technical conditions. In addition, we show how to include hard constraints in the part of the factor graph corresponding to belief propagation. Finally, we demonstrate an application of our method to iterative channel estimation and decoding in an OFDM system.
I E E E Transactions on Information Theory, 2013, Vol 59, Issue 1, p. 588-602