A Greedy Spreading Serial Decoding of LT Codes

Abstract

In this paper, we propose new serial decoding of Luby transform (LT) codes over additive white Gaussian noise channels. LT encoder generates a potentially limitless number of encoded packets, and the decoder incrementally collects the packets to ensure successful recovery of the information. In the proposed algorithm, the newly coming code nodes are the first to pass the messages, and it is their neighboring source nodes that will receive these input messages and update their output messages; then, the next neighboring code nodes that have not been covered are to be included in the updating group; in this greedy way, the message propagation is conducted from neighbors to neighbors. The analysis demonstrates that the proposed algorithm has a faster convergence speed than the conventional ones, and simulation shows that it has an effective bit error rate performance.