  In this paper, we propose a new early termination method (ETM) for Luby
transform (LT) belief propagation (BP) decoder. The proposed ETM, which we call
least reliable messages (LRM), observes only sign alterations of a small
cluster in log-likelihood ratio (LLR) messages passing between nodes in BP
decoder. Simulation results and complexity analyzes show that LRM significantly
lower computational complexity of early termination section in decoder without
any performance degradation and decreases the average decoding iteration
amounts compared to conventional ETMs in literature. The method can be easily
applied to code families which can be decoded by BP such as low density parity
check (LDPC) codes, polar codes and Raptor codes.
