Cross-Layer Iterative Decoding of Irregular LDPC Codes using Cyclic Redundancy Check Codes

This paper presents a cross-layer iterative decoder for irregular low-density parity-check (LDPC) codes which uses cyclic redundancy check (CRC) codes. The key idea of the decoder is to use correctly decoded frames as an aid for correcting the remaining erroneous frames. To accomplish this, the decoder exchanges the relevant information between layers by using the cross-layer design method and an iterative decoding architecture. Moreover, the unequal-error protection (UEP) property of irregular LDPC is exploited and both the multiple-error detection and single-error correction capabilities of the CRC code are used. Simulation results show that the proposed decoder outperforms the pure sum-product algorithm (SPA) decoder by a considerable gain while the increase in complexity is moderate. Furthermore, the error floor of irregular LDPC codes in the high Eb/NO regime can be lowered effectively. The proposed cross-layer iterative decoder can be used for any irregular LDPC coded wireless system to boost the performance and lower the error floor.