Low power LDPC decoder with efficient stopping scheme for undecodable blocks

An efficient technique for early detection of undecodable blocks during LDPC decoding is introduced. The proposed method avoids unnecessary decoding iterations by predicting decoding failure and therefore results in significant improvement in power and latency in low SNR values. The proposed method which has a low hardware overhead compares the parity checksum against predefined threshold values for three iterations and terminates decoding if a condition is met. A 5.25 mm² 10GBASE-T Split-Row Threshold decoder is implemented using the proposed technique in 65 nm CMOS. The postlayout results show that at low SNR value of 3.0 dB, the decoder requires 2.3 times fewer decoding iterations which results in 23 pJ/bit energy dissipation. This is 2.4 times lower than the energy dissipation of Split-Row Threshold decoder without the proposed early stopping technique.