A Simple Family of Non-Linear Analog Codes

We propose novel non-linear graph-based analog codes that directly encode $k$ real-valued source samples into $n$ real-valued samples by using (non-linear) sample-by-sample soft quantization of the input samples followed by a linear transformation on the soft-quantized values. Different from existing analog coding schemes, the proposed analog codes are able to produce additional output symbols in a rateless manner and can be decoded utilizing message passing algorithms dealing with real-valued nodes, achieving a performance close to the theoretical limits.