Weighted zigzag decodable fountain codes for unequal error protection

Abstract

Abstract By combining bit‐shift and exclusive‐or operations, a weighted zigzag decodable fountain code is proposed to achieve an unequal error protection property. In the proposed scheme, the input symbols of different importance levels are first pre‐coded into variable nodes using low‐density parity‐check codes. Then, bit‐shift operations prior to exclusive‐or are performed on the non‐uniformly selected variable nodes to generate encoded symbols. An analysis of the erasure probabilities based on the and‐or tree is further introduced. Simulation results show that by appropriately choosing the maximum bit‐shift amount, the proposed weighted zigzag decodable fountain codes can successfully recover the more important input symbols prior to the less important ones.