Erasure decoding for LDPC-coded FH-OFDMA system in downlink cellular environments - Electronics Letters

Introduction: Efficient packet based transmission with high data rate and high quality is considered as one of the requirements for future mobile communication systems [1]. In addition, a frequency reuse factor of one is preferred to make the cell planning and spectrum allocation easier. Frequency hopping orthogonal frequency division multiple access (FH-OFDMA) is among the multiple access candidates to meet such requirements owing to its capability of avoiding intracell interference and averaging the intercell interference (ICI). However, in cases of different power allocation and loading for each interferer in adjacent cells, the ICI pattern can be highly nonuniform in FH-OFDMA systems. Thus, such non-uniform ICI should be effectively managed, especially at cell boundaries, to achieve a frequency reuse factor of one. Previous work to combat interference has focused on the spread FH systems using Reed-Solomon codes with errors and erasures decoding [2, 3]. An iterative channel estimation and decoding method was also proposed for a convolutionally coded slow FH system [4], but it is desirable in the downlink with fast FH where only one or two symbols are involved in noise variance estimation. In this Letter, we employ low-density parity check (LDPC) codes [5, 6] in FH-OFDMA systems and propose simple erasure decoding methods to effectively decode the partially or uniformly interfered packet without knowing the ICI power and the location of the symbols corrupted by high power interference.