Low density lattice codes for the relay channel

We study practical, efficient codes for the Gaussian relay channel. It has been demonstrated that low-density lattice codes (LDLCs) can provide near-capacity performance for point-to-point Gaussian channels. We present an LDLC formulation that provides performance near the decode-and-forward inner bound of the relay channel capacity. We employ a superposition block Markov strategy tailored to LDLCs and design an appropriate iterative decoder. We characterize the error performance via simulations, showing that our scheme achieves performance only 2dB away from the decode-and-forward bound.