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Efficient Helicopter-Satellite Communication Scheme Based on Check-Hybrid LDPC Coding

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Tsinghua Science and Technology 2018年第3期23卷 323-332页

作者： Ping Wang liuguo yin Jianhua Lu Department of Electronic Engineering Tsinghua University Beijing 100084 China EDA Laboratory Research Institute of Tsinghua Universityin Shenzhen Shenzhen 518057 China. School of Information Science andTechnology Tsinghua University Beijing 100084 China EDA Laboratory Research Institute ofTsinghua University in Shenzhen Shenzhen 518057 China Department of Electronic Engineering Tsinghua University Beijing 100084 China

When implementing helicopter-satellite communications, periodical interruption of the received signal is a challenging problem because the communication antenna is intermittently blocked by the rotating blades of the helicopter. The helicopter-satellite channel model and the Forward Error Control（FEC） coding countermeasure are presented in this paper. On the basis of this model, Check-Hybrid（CH） Low-Density Parity-Check（LDPC）codes are designed to mitigate the periodical blockage over the helicopter-satellite channels. The CH-LDPC code is derived by replacing part of single parity-check code constraints in a Quasi-Cyclic LDPC（QC-LDPC） code by using more powerful linear block code constraints. In particular, a method of optimizing the CH-LDPC code ensemble by searching the best matching component code among a variety of linear block codes using extrinsic information transfer charts is proposed. Simulation results show that, the CH-LDPC coding scheme designed for the helicopter-satellite channels in this paper achieves more than 25% bandwidth efficiency improvement, compared with the FEC scheme that uses QC-LDPC codes.

关键词： helicopter-satellite communications check-hybrid Low-Density Parity-Check(LDPC) codes Extrinsic Information Transfer(EXIT) iterative decoding

Code Hop: physical layer error correction and encryption with LDPC-based code hopping

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Science China(Information Sciences) 2016年第10期59卷 121-135页

作者： Zhao CHEN liuguo yin Yukui PEI Jianhua LU Department of Electronic Engineering Tsinghua University Electronic Design Automation (EDA) Laboratory Research Institute of Tsinghua University in Shenzhen School of Aerospace Tsinghua University

This paper proposes a novel scheme named Code Hop, which provides both information reliability and security using code hopping based on low-density parity-check(LDPC) codes. In contrast to traditional systems that perform error correction and encryption at different layers, Code Hop combines these two operations into a single step at physical layer, such that each plaintext message is jointly encoded and encrypted by a hopping parity-check matrix. According to a pseudo-random number generator(PRNG), the hopping matrix may rapidly switch among a sequence of LDPC parity-check matrices, which is randomly generated by a structured-random protograph expanding technique. Simulations show that reliable communication can be achieved by Code Hop with good error-correcting performance. In the meantime, Code Hop may improve the security of traditional systems such as GSM. Taking the A5/1 stream cipher used in GSM as the PRNG, it is shown that Code Hop is resistant to existing chosen-plaintext attacks that break A5/1 cipher already. Moreover, the security of Code Hop will be enhanced in the presence of channel errors as well.

关键词： physical layer security error correction data encryption low-density parity-check codes code hopping

Design and Efficient Hardware Implementation Schemes for Non-Quasi-Cyclic LDPC Codes

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Tsinghua Science and Technology 2017年第1期22卷 92-103页

作者： Baihong Lin Yukui Pei liuguo yin Jianhua Lu Department of Electronic Engineering Tsinghua UniversityBeijing 100084 China School of Aerospace Tsinghua UniversityBeijing 100084

The design of a high-speed decoder using traditional partly parallel architecture for Non-Quasi-Cyclic（NQC） Low-Density Parity-Check（LDPC） codes is a challenging problem due to its high memory-block cost and low hardware utilization efficiency. In this paper, we present efficient hardware implementation schemes for NQCLDPC codes. First, we propose an implementation-oriented construction scheme for NQC-LDPC codes to avoid memory-access conflict in the partly parallel decoder. Then, we propose a Modified Overlapped Message-Passing（MOMP） algorithm for the hardware implementation of NQC-LDPC codes. This algorithm doubles the hardware utilization efficiency and supports a higher degree of parallelism than that used in the Overlapped Message Passing（OMP） technique proposed in previous works. We also present single-core and multi-core decoder architectures in the proposed MOMP algorithm to reduce memory cost and improve circuit efficiency. Moreover, we introduce a technique called the cycle bus to further reduce the number of block RAMs in multi-core decoders. Using numerical examples, we show that, for a rate-2/3, length-15360 NQC-LDPC code with 8.43-d B coding gain for Binary PhaseShift Keying（BPSK） in an Additive White Gaussian Noise（AWGN） channel, the decoder with the proposed scheme achieves a 23.8%–52.6% reduction in logic utilization per Mbps and a 29.0%–90.0% reduction in message-memory bits per Mbps.

关键词： Non-Quasi-Cyclic(NQC) Low-Density Parity-Check(LDPC) codes decoder design Modified Overlapped Message Passing(MOMP) algorithm hardware utilization efficiency

Generalized Low-Density Parity-Check Coding Scheme with Partial-Band Jamming

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Tsinghua Science and Technology 2014年第2期19卷 203-210页

作者： Qi Li Xinru Qu liuguo yin Jianhua Lu the Department of Electronic Engineering Tsinghua University the School of Aerospace Tsinghua University

In this study, a class of Generalized Low-Density Parity-Check （GLDPC） codes is designed for data transmission over a Partial-Band Jamming （PBJ） environment. The GLDPC codes are constructed by replacing parity-check code constraints with those of nonsystematic Bose-Chaudhuri-Hocquenghem （BCH）, referred to as Low-Density Parity-Check （LDPC）-BCH codes. The rate of an LDPC-BCH code is adjusted by selecting the transmission length of the nonsystematic BCH code, and a low-complexity decoding algorithm based on message- passing is presented that employs A Posteriori Probability （APP） fast BCH transform for decoding the BCH check nodes at each decoding iteration. Simulation results show that the LDPC-BCH codes with a code rate of 1/8.5 have a bit error rate performance of 1 x10-8 at signal-noise-ratios of -6.97 dB, -4.63 dB, and 2.48 dB when the fractions of the band jammed are 30%, 50%, and 70%, respectively.

关键词： Generalized Low-Density Parity-Check (GLDPC) code constraint nonsystematic BCH code a posterioriprobability fast BCH transform

Quantum secure direct communication with entanglement source and single-photon measurement

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Science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 12-19页

作者： Lu Yang JiaWei Wu ZaiSheng Lin liuguo yin GuiLu Long State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijing 100084China Frontier Science Center for Quantum Information Beijing 100084China School of Information and Technology Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Beijing 100084China Beijing Academy of Quantum Information Sciences Beijing 100093China

Quantum secure direct communication(QSDC)transmits information directly over a quantum *** addition to security in transmission,it avoids loopholes of key loss and prevents the eavesdropper from getting *** this article,we propose a QSDC protocol using entangled photon *** protocol differs from existing entanglement-based QSDC protocols because it does not perform Bell-state measurement,and one photon of the entangled pair is measured after the entanglement *** has the advantage of high signal-to-noise ratio due to the heralding function of entanglement pairs,and it also has the relative ease in performing single-photon *** protocol can use a practical entanglement source from spontaneous parametric down-conversion(SPDC);Gottesman-Lo-Lu¨tkenhaus-Preskill theory and the decoy state method give a better estimate of the error *** analysis is completed with Wyner’s wiretap channel theory,and the lower bound of the secrecy capacity is *** simulations were carried out to study the performance of the *** simulations demonstrated that the protocol with a practical SPDC entanglement source performed well and was close to the case with an ideal entanglement source.

关键词： quantum secure direct communication quantum secure communication quantum communication quantum information

Secure routing and transmission scheme for space-ocean broadband wireless network

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Science China(Information Sciences) 2020年第4期63卷 239-241页

作者： Yuzhou FU Chuan-Ao JIANG Yurong QIN liuguo yin School of Computer and Electronics Information Guangxi University Key Laboratory of EDA Research Institute of Tsinghua University in Shenzhen School of Information Science and Technology Tsinghua University

Dear editor,Increase in maritime activities with exclusive economic zones leads to an increase in demands for information security in maritime communication networks. In maritime, all ships must install an automatic i... 详细信息

关键词： Secure routing and transmission scheme for space-ocean broadband wireless network

Realization of quantum secure direct communication over 100 km fiber with time-bin and phase quantum states

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Light(Science & Applications) 2022年第5期11卷 787-795页

作者： Haoran Zhang Zhen Sun Ruoyang Qi liuguo yin Gui-Lu Long Jianhua Lu State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijingChina Beijing Academy of Quantum Information Science BeijingChina School of Information and Technology Tsinghua UniversityBeijingChina Beijing Institute of Spacecraft System Engineering BeijingChina Frontier Science Center for Quantum Information BeijingChina Beijing National Research Center for Information Science and Technology BeijingChina

Rapid progress has been made in quantum secure direct communication in recent *** practical application,it is important to improve the performances,such as the secure information rate and the communication *** this paper,we report an elaborate physical system design and protocol with much enhanced *** design increased the secrecy capacity greatly by achieving an ultra-low quantum bit error rate of<0.1%,one order of magnitude smaller than that of existing *** to previous systems,the proposed scheme uses photonic time-bin and phase states,operating at 50 MHz of repetition rate,which can be easily upgraded to over 1 GHz using current on-the-shelf *** results of our experimentation demonstrate that the proposed system can tolerate more channel loss,from 5.1 dB,which is about 28.3 km in fiber in the previous scheme,to 18.4 dB,which corresponds to fiber length of 102.2 ***,the experiment shows that intercity quantum secure direct communication through fiber is feasible with present-day technology.

关键词： fiber communication quantum

Measurement-device-independent quantum secure direct communication

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Science China(Physics,Mechanics & Astronomy) 2020年第3期63卷 2-7页

作者： ZengRong Zhou Yu Bo Sheng PengHao Niu liuguo yin GuiLu Long Lajos Hanzo State Key Laboratory of Low-dimensional Quantum Physics Beijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China Collaborative Innovation Center of Quantum Matter Beijing 100084China Beijing Academy of Quantum Information Beijing 100084China Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China College of Telecommunications&Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China Beijing National Research Center for Information Science and Technology Beijing 100084China School of Information and Technology Tsinghua UniversityBeijing 100084China School of Electronics and Computer Science University of SouthamptonSouthampton SO171BJUK

Quantum secure direct communication(QSDC)is a unique technique,which supports the secure transmission of confidential information directly through a quantum channel without the need for a secret key and for *** this secure communication protocol fundamentally differs from its conventional *** this article,we report the first measurement-deviceindependent(MDI)QSDC protocol relying on sequences of entangled photon pairs and single ***,it eliminates the security loopholes associated with the measurement ***,this MDI technique is capable of doubling the communication distance of its conventional counterpart operating without using our MDI *** also conceive a protocol associated with linear optical Bell-basis measurements,where only two of the four Bell-basis states could be *** the number of qubits in a sequence reduces to 1,the MDI-QSDC protocol degenerates to a deterministic MDI quantum key distribution protocol.

关键词： quantum information secure communication quantum communication

Generalized sparse codes for non-Gaussian channels:Code design,algorithms,and applications

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Fundamental Research 2022年第2期2卷 284-295页

作者： Zhao Chen Zhen Sun Yukui Pei liuguo yin Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Frontier Science Center for Quantum Information Beijing 100084China

In this paper,generalized sparse(GS)codes are proposed to support reliable and efficient transmission over non-Gaussian ***,by expanding the single-parity check(SPC)code constraints with powerful algebraic codes,GS codes generalize conventional sparse codes with enhanced error-correcting capability,as well as better code design flexibility by covering a wide range of block-lengths and coding rates with reduced encoding/decoding ***,by introducing a universal communication channel model,a general framework for performance analysis and code design of GS codes is formulated,by which the coding parameters can be optimized for different target channel ***,example codes are constructed for several critical application scenarios with non-Gaussian *** simulations are performed to demonstrate the superiority of the proposed GS coding scheme to traditional channel coding schemes.

关键词： Generalized sparse codes Low-density parity-check codes Low-density BCH codes Non-Gaussian channels EXIT Chart analysis