Rate-compatible schemes for link adapted LDPC codes in IEEE 802.16e standard

IEEE P802.16e standard specifies the construction of low-density parity-check (LDPQ codes with four different code rates, i.e. 1/2, 2/3, 3/4, 5/6, and totally six parity check matrices. However, such a coarse coding rate granularity cannot provide comparable link adaptation performance comparing to Turbo codes in HSDPA, In another aspect, more mother codes lead to much higher complexity of encoder implementation due to individual parity check matrices. To reach a balance between the implementation complexity and the fine granularity in link adaptation, this paper investigates the performance of the rate-compatible (RC) scheme, with targeted coding rate varing from 0.1 to 0.9, based on different sets of mother LDPC codes. As a summary, this paper proposes an instruction of mother codes selection and RC schemes for different targeted coding rates, which makes the link adaptation of LDPC codes very convenient for WiMAX systems.