Construction of multi-rate high performance QC-LDPC codes with low implementation complexity

Multi-rate LDPC codes with near Shannon limit performance are highly demanded in digital television terrestrial broadcasting (DTTB) system. Several proposals have been carried out to construct multi-rate LDPC codes, among which, Row-combining and Row-splitting with Edge Variation (RCSEV) helps construct LDPC codes with constant code length and simple hardware architecture. Besides, Column Extension (CE) is also an effective method for rate-compatible LDPC code design. This paper proposes an improved scheme of Row-Combining and splitting with Edge Variation and Column Deletion (RCSEV-CD), which is the rational combination of RCSEV and CE. RCSEV is carried out to generate multi-rate LDPC codes sharing the same code length in basic code group. The codes in extended code group are generated via CD, ensuring same code length in each extended code groups. Multi-rate codes within a code group improves the flexibility of a service while the code groups meet the requirement of multiple services. EXIT chart analysis helps guide the trade-off between column degree distributions among multiple rates. A comparison with multi-rate codes in DVB-S2 is performed via bit error rate (BER) simulation and the result shows the superior performance of our designed codes at typical code rates.