Half-duplex relaying with serially concatenated low-density generator matrix (SCLDGM) codes

Recently, the integration of cooperation with coding has proven to be a very useful technique to enhance relay system performance. Relay systems based on low-density parity-check (LDPC) codes have the potential to approach the theoretical information limits very closely. However, LDPC codes have a disadvantage in that the encoding complexity is high. To solve this problem, serially concatenated low-density generator matrix (SCLDGM) codes are attracting attention owing to their low encoding complexity. However, the performance of SCLDGM coded relaying has not been investigated. In this paper, we apply SCLDGM codes to relay channel with the motivation of lowering the encoding complexity. Since SCLDGM codes are concatenated codes, we cannot use the same method as LDPC coded relaying. We propose a new relaying system and three cooperation protocols suited for SCLDGM codes. Computer simulation results show that the bit error rate (BER) performance of the proposed system is equal to that of conventional LDPC coded relaying system.