Two-layer rateless codes over lattices for Gaussian broadcast channels

In this paper, we present a class of rateless coset codes, which consists of two layers. The first layer is protected by a systematic lattice-Kite code, which takes as input a sequence of coset leaders and delivers as output a sequence of coset leaders with redundancy. The second layer is for shaping, which can be implemented by using a (possibly coded) binary sequence to select lattice points from each coset. Based on the presented two-layer lattice-Kite code, we propose a rateless transmission scheme for two-user Gaussian broadcast channels (TU-GBC), where the common information and the private information are carried by the first layer and the second layer, respectively. The proposed scheme allows the user with good channel conditions to collect more private information. Simulation results are given to show the effectiveness of the proposed rateless transmission scheme.