本论文研究了基于同步DS-CDMA协作通信系统的迭代接收机性能,该系统在协作伙伴节点端和基站端均使用由随机数据联合检测器与LDPC译码器级联(PDA+LDPC,probabilistic data association+low density parity check codes)所组成的迭代接收...本论文研究了基于同步DS-CDMA协作通信系统的迭代接收机性能,该系统在协作伙伴节点端和基站端均使用由随机数据联合检测器与LDPC译码器级联(PDA+LDPC,probabilistic data association+low density parity check codes)所组成的迭代接收机,利用从该迭代接收机所提供的信息,提出了一种集中式协作伙伴节点选择策略。根据该策略,由于距离基站较近的节点与基站间通信能力相对较强,每个信源节点将优先选择距离基站近的节点作为其协作伙伴节点,仿真结果表明,本文所提出的集中式协作伙伴节点选择策略可取得较好的系统性能。展开更多
[目的]建立“染红食品”中苏丹红Ⅰ、Ⅱ、Ⅲ和Ⅳ残留量的高效液相色谱(HPLC)初筛、质谱确认分析方法。[方法]以Merck RP-18柱为分析柱,流动相:乙腈∶水=90∶10,Waters-2996二极管矩阵检测器(PDA)和FinniganLCQ Deca XP MAX质谱仪为检测...[目的]建立“染红食品”中苏丹红Ⅰ、Ⅱ、Ⅲ和Ⅳ残留量的高效液相色谱(HPLC)初筛、质谱确认分析方法。[方法]以Merck RP-18柱为分析柱,流动相:乙腈∶水=90∶10,Waters-2996二极管矩阵检测器(PDA)和FinniganLCQ Deca XP MAX质谱仪为检测器。[结果]回归方程和相关系数为:苏丹红Ⅰ:y=0.163104x+0.019217,r=0.99993;苏丹红Ⅱ:y=0.153674x-0.2212981,r=0.99993;苏丹红Ⅲ:y=0.305919x-5.0810264,r=0.9997;苏丹红Ⅳ:y=0.239273x-5.260669,r=0.9997。平均回收率(%):87.3、83.0、86.7和90.0。[结论]用HPLC-PDA-MS法检测食品中的苏丹红方法简便,重现性好,灵敏度高,定性准确,定量精确。展开更多
针对同步DS-CDMA协作通信系统,本文考虑在转发节点端和基站端使用随机数据联合检测算法(probabilistic data association algorithm,PDA)与LDPC码译码器级联的迭代接收机PDA+LDPC,基于该迭代接收机结构,给出了一种分布式协作通信策略,...针对同步DS-CDMA协作通信系统,本文考虑在转发节点端和基站端使用随机数据联合检测算法(probabilistic data association algorithm,PDA)与LDPC码译码器级联的迭代接收机PDA+LDPC,基于该迭代接收机结构,给出了一种分布式协作通信策略,研究表明,该策略较集中式协作伙伴选择策略和传统的DAF协作通信策略可取得更好的系统性能。展开更多
This paper considers the uplink of a cooperative Code-Division Multiple-Access (CDMA) system where parts of mobile nodes serve as source nodes while the others serve as relay nodes at any instant in time. When the non...This paper considers the uplink of a cooperative Code-Division Multiple-Access (CDMA) system where parts of mobile nodes serve as source nodes while the others serve as relay nodes at any instant in time. When the non-orthogonal spreading codes are adopted,Multiple Access Interference (MAI) will exist at both the relay nodes and the base node,causing diversity gain to diminish. To mitigate MAI and exploit full advantages of cooperation,the Probabilistic Data Association (PDA) is developed at the relay nodes and the base node. Simulation results demonstrate that some performance gains can be obtained by the PDA detector over the Minimum Mean Square Error (MMSE) detector at high Signal-to-Noise Ratio (SNR) and conversely at low SNR.展开更多
文摘本论文研究了基于同步DS-CDMA协作通信系统的迭代接收机性能,该系统在协作伙伴节点端和基站端均使用由随机数据联合检测器与LDPC译码器级联(PDA+LDPC,probabilistic data association+low density parity check codes)所组成的迭代接收机,利用从该迭代接收机所提供的信息,提出了一种集中式协作伙伴节点选择策略。根据该策略,由于距离基站较近的节点与基站间通信能力相对较强,每个信源节点将优先选择距离基站近的节点作为其协作伙伴节点,仿真结果表明,本文所提出的集中式协作伙伴节点选择策略可取得较好的系统性能。
文摘[目的]建立“染红食品”中苏丹红Ⅰ、Ⅱ、Ⅲ和Ⅳ残留量的高效液相色谱(HPLC)初筛、质谱确认分析方法。[方法]以Merck RP-18柱为分析柱,流动相:乙腈∶水=90∶10,Waters-2996二极管矩阵检测器(PDA)和FinniganLCQ Deca XP MAX质谱仪为检测器。[结果]回归方程和相关系数为:苏丹红Ⅰ:y=0.163104x+0.019217,r=0.99993;苏丹红Ⅱ:y=0.153674x-0.2212981,r=0.99993;苏丹红Ⅲ:y=0.305919x-5.0810264,r=0.9997;苏丹红Ⅳ:y=0.239273x-5.260669,r=0.9997。平均回收率(%):87.3、83.0、86.7和90.0。[结论]用HPLC-PDA-MS法检测食品中的苏丹红方法简便,重现性好,灵敏度高,定性准确,定量精确。
文摘针对同步DS-CDMA协作通信系统,本文考虑在转发节点端和基站端使用随机数据联合检测算法(probabilistic data association algorithm,PDA)与LDPC码译码器级联的迭代接收机PDA+LDPC,基于该迭代接收机结构,给出了一种分布式协作通信策略,研究表明,该策略较集中式协作伙伴选择策略和传统的DAF协作通信策略可取得更好的系统性能。
基金Supported by the National Natural Science Foundation of China (No. 60772061)Science Foundation of Nanjing University of Posts and Telecommunications (No. NY207132)the Postdoctoral Research Programs (No. 0801054B)
文摘This paper considers the uplink of a cooperative Code-Division Multiple-Access (CDMA) system where parts of mobile nodes serve as source nodes while the others serve as relay nodes at any instant in time. When the non-orthogonal spreading codes are adopted,Multiple Access Interference (MAI) will exist at both the relay nodes and the base node,causing diversity gain to diminish. To mitigate MAI and exploit full advantages of cooperation,the Probabilistic Data Association (PDA) is developed at the relay nodes and the base node. Simulation results demonstrate that some performance gains can be obtained by the PDA detector over the Minimum Mean Square Error (MMSE) detector at high Signal-to-Noise Ratio (SNR) and conversely at low SNR.
