LDPC Decoder Applications

Along with DVB-S2 and the drafts of IEEE 802.11n, Mobile WiMAX (Worldwide Interoperability for Microwave Access) was one of the first standards to adopt LDPC codes for forward error correction. Mobile WiMAX was first defined in IEEE 802.16e-2005 as an amendment to IEEE 802.16-2004, and later consolidated into IEEE 802.16-2009. The throughputs of WiMAX systems are typically much less than 100 Mbit/s. Using the LDPC codes is optional.

The standard offers the highest block length flexibility of all standards that apply LDPC codes. Overall 19 block lengths are defined. Each block length comes with four code rates. For two code rates (rate 2/3 and rate 3/4 the standard defines two different LDPC codes with minor differences in error correction performance. All in all, 114 LDPC codes are contained within the WiMAX standard. However, only six parity check matrices are used to derive all other matrices. The usage of LDPC coding is optional, only convolutional coding is mandatory.

The same LDPC codes are used within the IEEE 802.22 and ITU-T G.hn standards, see below.