Efficient Implementation of Low-Density Parity-Check Convolutional Code Encoders With Built-In Termination

Low-density parity-check convolutional codes (LDPC-CCs) have demonstrated comparable error-correcting performance to LDPC block codes (LDPC-BCs). However, the LDPC-CC encoder requires termination when applied to finite-length data frames to ensure that the trailing information bits are fully protected. In this paper, the LDPC-CC encoder design is investigated, and a novel termination scheme is proposed. Starting from any encoder state, the proposed scheme is capable of generating a termination sequence in hardware without padding, thus minimizing the rate loss due to termination. A high-speed architecture for LDPC-CC encoders with built-in termination is proposed. Synthesis results for LDPC-CCs of code memory size up to 512 demonstrate maximum encoding throughputs of around 1 Gb/s for a 90-nm CMOS technology. The implementation cost for such encoders is shown to be reasonably low for average-sized LDPC-CCs.