Improved rate-compatible low-density parity-check codes with applications to wireless channels

Strong rate-compatible codes are important to achieve high throughput in hybrid automatic repeat request with forward error correction (ARQ/FEC) systems in networks utilizing packet data transmission. This thesis focuses on the construction of efficient rate-compatible low density parity check (RC-LDPC) codes over a wide rate range. Two LDPC code families are considered: The regular LDPC family which is known for good performance and low error floor, and semi-random LDPC which offers performance similar to Regular LDPC codes and also enables low encoding complexity. Efficient RC-LDPC codes are constructed and a hybrid ARQ/FEC system using RC-LDPC codes is evaluated. Compared to existing ARQ/FEC systems [1], the proposed system based on semi-random LDPC codes offers the advantages of low encoding complexity and higher throughput. The application of rate-compatible semi-random codes to systems employing coded cooperation diversity is investigated. Additionally, an algorithm is developed for the removal of small loops from semi-random LDPC codes.