Analog fountain codes with unequal error protection property

In this paper, we propose a novel rateless code with unequal error protection (UEP) property based on recently proposed analog fountain codes (AFCs). AFCs have been originally designed and optimized to approach the capacity of a Gaussian channel in a wide range of signal to noise ratios (SNRs). In this paper, we are particularly interested in the UEP property of AFC codes, providing different levels of error protection for various sets of information symbols. In the proposed AFC code with UEP property (AFC-UEP), the whole block of information symbols is partitioned into several parts, where each part requires a certain level of error protection. Each part is then assigned with a selection probability and a code degree, which are optimized based on the error probability analysis of the AFC code to satisfy the required error protection levels of all information parts. Simulation results show that the proposed scheme can effectively provide an unequal error protection for different sets of information symbols. Moreover, various error protection requirements can be simply achieved by optimizing the code degree and the selection probability of each part; thus, achieving the desired level of error protection for each part.