For the Chip's Design of LTE Turbo Code Optimization

该文分析了lTE系统中TurbO码的译码,并针对定点运算的特点进行了改进。通过大量的仿真确定了定点lOg-MAP译码算法的关键参数。量化比特数和AWgn中gAIn值,外在(EXTrInSIC)信息因子以及定点化、归一化、溢出处理等操作,这些处理使得该译码算法在译码性能上接近浮点lOg-MAP译码算法,对于TurbO译码在硬件上的实现具有一定的参考价值。This article analyze Turbo decoder in LTE system,And the characteristics for the fixed-point arithmetic has been improved.By a large number of simulation Determined the key parameters on fixed-point LOG-MAP decoding algorithm,Including the number of quantization bits and value of GAIN in AWGN,extrinsic information factor and Fixed point,Normalized,overflow operation,Such treatment makes the decoding algorithm in decoding performance close to the classic LOG-MAP decoding algorithm,for Turbo decoding implementation in hardware has some reference value

Implementation of License File Scheme Through Modified Digital Signature Scheme Based on PKI

基于软件的保护方式主要有注册码和许可证文件,文章介绍了将单向散列函数同公开密钥相结合实现数字签名的技术,提出了一种软件许可证生成、验证的许可系统,并基于gnu开源库lIbgCryPT为电信设备实现许可证系统。与传统技术相比,该系统具有简单易用、安全可靠的特点。There are two main methods,i.e.License Key and License File in software copyrights protection area based on soft mode.This paper constructed digital signature adopting public key cryptography technique and Hashing,and then proposed a new license flie generation and validation system,and also gave detailed design and implemention based on Libgcrypt which belongs to GNU.This system is easier and safer to use

Security of a position-based secret key generation method

随着无线与移动通信个人业务的快速发展,利用无线信道的特性生成密钥的方法成为新的研究热点,但这种方法并非绝对安全。当窃听者获得足够的散射环境信息和用户位置信息,就可能重构出合法用户之间的信道信息,影响密钥的安全性。其中用户和窃听者共同的散射环境难以做到对窃听者保密,但用户位置信息由于用户移动和窃听者有限的观测能力具备不确定性,能够为密钥生成提供安全保障。该文以密钥生成速率为安全性的衡量,研究了基于合法用户位置信息的密钥生成速率。首先推导了窃听者对不同场景(视距、非视距和不同散射物数量)中的用户位置推测误差表达式;然后通过仿真,分析了窃听者对距离和角度不同观测误差、同一密钥生成周期内不同的信道观测次数对密钥生成速率的影响;基于仿真和分析结果,证明了利用用户位置不确定度能够保障一定的密钥生成速率,从而确保了密钥的安全。With the increasing demand for security,many systems take advantage of channel randomness to generate secret keys.However, when an eavesdropper has good knowledge of the environmental information and the position information of legal users,this method is not absolutely safe.The scattering environmental information cannot be kept secret but the system can still be secure based on the uncertainty of the positions of legal users due to the users movements and the limited observation ability of the eavesdroppers.This study analyzes the security of the position-based secret keys generation method with the security measured by the secret key rates.The calculational errors of the positions of the legal users in different scenarios(LOS,NLOS and different numbers of scattering objects)are analyzed first.Then,the impacts of the distance observation error,the azimuth observation error and the number of observations in each secret key generation period on the secret key rates are analyzed in simulations.The results show that the uncertainty of the positions of legal users can be used to provide security for the secret keys.国家“九七三”重点基础研究项目(2013CB329002); 国家“八六三”高技术项目(2012AA01A502); 国家自然科学基金青年基金(61201192); 国家科技重大专项项目(2013ZX03001024-004); 国际科技合作计划(2012DFG12010); 教育部科学技术研究重点资助项目(313005); 清华大学自主科研项目(2011Z02292); 东南大学移动通信国家重点实验室开放研究基金(2012D02

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies