Design of shortened LDPC codes based on IEEE802.16e protocol without short cycles
Wang Bin-bin · Journal of Computer Applications · 2011
The shortened LDPC codes,based on the current IEEE802.16e standard,have plenty of small girths.In order to resolve this problem,this paper proposed a new scheme of designing the shortened LDPC codes.In the proposed scheme,the design has modified the sub-parity check matrix under the frame of the IEEE802.16e Standard.The proposed check matrix with the spreading factor(zf=48) was constructed with quasi-cyclic matrix method and finite geometry method.Moreover,parity check points searched the node degree in synchronous sequence,and the proposed sub-parity check matrix has minor girth-6 and no girth-4.The results of simulation in the AWGN(Additive White Gaussion Noise) channels show that the improved short code with the code rate approaching to 0.5,can fast encode as excellently as the IEEE802.16e protocol.Moreover,a good BER(Bit Error Rate) performance of the proposed code is 1.1 dB more than the Shannon limit of this channel.