Spatially coupled LDPC-BCH codes in quantum secure direct communications
WANG Ping1, SUN Zhen1, YIN Liuguo2,3,4, LU Jianhua1,2
1. Department of Electronic Engineering, Tsinghua University, Beijing 100084, China; 2. School of Information Science and Technology, Tsinghua University, Beijing 100084, China; 3. Beijing National Research Center for Information Science and Technology, Beijing, 100084, China; 4. Key Laboratory of EDA, Research Institute of Tsinghua University in Shenzhen, Shenzhen, 518057, China
Abstract:Quantum secure direct communication systems are limited by high erasure probabilities and low receiving probabilities due to the high light source losses in the optical elements and optical fibers. A channel mitigation method based on spatially coupled LDPC-BCH codes is presented here to ensure reliable information transformations in quantum secure direct communication systems to resolve the problems of low-rate and Shannon limit-approaching code designs. Spatially coupled LDPC-BCH codes are constructed by coupling multiple identical block LDPC-BCH codes with edge spreading. The extrinsic information transfer functions of the spatially coupled LDPC-BCH code are analyzed to derive the decoding thresholds for the code ensembles. Simulations show that the spatially coupled LDPC-BCH codes have decoding thresholds closer to the Shannon limit with lower bit error rates than block LDPC-BCH codes. The spatially coupled LDPC-BCH code channel mitigation scheme has a transmitting efficiency of 0.001 and a bit error rate less than 10-6 when the channel receiving probability is set at 0.4%.
王平, 孙臻, 殷柳国, 陆建华. 用于量子安全直接通信的空间耦合LDPC-BCH码[J]. 清华大学学报(自然科学版), 2019, 59(9): 737-743.
WANG Ping, SUN Zhen, YIN Liuguo, LU Jianhua. Spatially coupled LDPC-BCH codes in quantum secure direct communications. Journal of Tsinghua University(Science and Technology), 2019, 59(9): 737-743.
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