Turbo-like Decoding Algorithm for Structured LDPC codes

This paper presents a high-speed "turbo-like" decoding algorithm for certain structured LDPC codes such as those adopted in IEEE 802.16e and in the draft 802.11n standards. It is shown that after a key modification, such LDPC codes may be processed as generalized repeat accumulate codes, codes which are known to support "turbo-like" decoding. A GRA-like encoder of structured LDPC codes is derived, which in turn leads to the decoding algorithm. It is also shown that the "structured" properties result in an inherent parallelism, leading to an efficient high speed decoder implementation