New construction of LDPC convolutional codes

In this paper, we propose a new construction of (3, t)-regular low-density parity-check convolutional codes by properly including binomial entries in the parity-check matrices. Both of the upper and lower bounds on free distance are derived for the new codes. Compared with previous constructions, our design can not only avoid codes of girth less than 8 but also provide enlarged free distances for some code rates. Simulation results show that the codes based on the new construction can achieve better bit-error-rate performance and lower error floor.