H-ARQ-Aided Systematic Luby Transform Codes

Hybrid Automatic-Repeat-Request (H-ARQ) Aided Systematic Luby Transform (SLT) Coded Modulation is proposed, where SLT codes are used both for correcting erroneous bits and for detecting as well as retransmitting erroneous Internet Protocol (IP) based packets. Erroneous IP packet detection is implemented using syndrome checking with the aid of the SLT codes’ Parity Check Matrix (PCM). Optimizing the mapping of SLT-encoded bits to modulated symbols and then using iterative decoding for exchanging extrinsic information between the SLT decoder and the demapper substantially improves the achievable Bit Error Ratio (BER) performance of the scheme. Quantitatively, at Eb/N0 in excess of 3.8 dB, this scheme is capable of achieving a BER ≤ 10 and up to 1.5 times higher throughput in comparison to less sophisticated benchmarker schemes such as SLT codes, dispensing with ARQ-assistance or joint SLT coded modulation and H-ARQ-SLT codes, when communicating over AWGN channels, using 16-QAM and a half-rate SLT code.