By exploring the deterministic characteristics of the measurement data, a new propagation model with two deterministic clusters and stochastic arriving rays within each cluster is proposed. When considering the cumula...By exploring the deterministic characteristics of the measurement data, a new propagation model with two deterministic clusters and stochastic arriving rays within each cluster is proposed. When considering the cumulative distribution function （CDF） of the three key channel statistics, the proposed model fits the measurement data better than SV/IEEE 802.15.3, a model which is known as a standard model for UWB indoor propagation channel. Therefore, with the additional knowledge of the specific environment geometry, the proposed model generating impulse responses ＂resemble＂ the measured channel impulse responses better than IEEE model. Moreover, the proposed model＇s parameters obtaining procedure is simplified by utilizing simple parameters of the environment.展开更多
In wireless networks, packet access is a popular mode, and the key problem is how to improve throughput and access delay performance, especially the throughput for wireless channels. These results will be a reference ...In wireless networks, packet access is a popular mode, and the key problem is how to improve throughput and access delay performance, especially the throughput for wireless channels. These results will be a reference for not only a wireless channel but also a common MAC protocol.展开更多
Wireless communication is easily disturbed by unfortunate factors which drive the wireless environment unstable and complicated. Therefore, it is essential to consider these factors in stability analysis of the wirele...Wireless communication is easily disturbed by unfortunate factors which drive the wireless environment unstable and complicated. Therefore, it is essential to consider these factors in stability analysis of the wireless network. However, wireless channel characteristics and packets collisions are neglected in the classical fluid model. A wireless TCP fluid model （WTFM） for stability analysis of wireless network is proposed based on cross layers, which not only makes the congestion control based on random early detection （RED） available for wireless network, but also provides a more accurate model to analyze the stability of wireless system theoretically. In the proposed model, active queue management, abnormality of wireless channels and packets collisions are taken into consideration. The comparisons between evaluating results from the WTFM and the practical performance from NS2 simulations validate the accuracy of the proposed WTFM in the perspectives of delay, dropping probability, throughput, sliding window size and queue length. A set of comparisons among the proposed WTFM, the classical fluid model and the convex optimization model are conducted. The results demonstrate that the proposed WTFM model performs better than other schemes in comprehensive aspects on capturing the characteristic of the wireless network and computing complexity.展开更多
Wireless capsule endoscopy(WCE) is a promising technique which has overcome some limitations of traditional diagnosing tools, such as the comfortlessness of the cables and the inability of examining small intestine se...Wireless capsule endoscopy(WCE) is a promising technique which has overcome some limitations of traditional diagnosing tools, such as the comfortlessness of the cables and the inability of examining small intestine section. However, this technique is still far from mature and asks for the feasible improvements. For example, the relatively low transmission data rate and the absence of the real-time localization information of the capsule are all important issues. The studies of them rely on the understanding of the electromagnetic wave propagation in human body. Investigation of performance of WCE communication system was carried out by studying electromagnetic(EM) wave propagation of the wireless capsule endoscopy transmission channel. Starting with a pair of antennas working in a human body mimic environment, the signal transmissions and attenuations were examined. The relationship between the signal attenuation and the capsule(transmitter) position, and direction was also evaluated. These results provide important information for real-time localization of the capsule. Moreover, the pair of antennas and the human body were treated as a transmission channel, on which the binary amplitude shift keying(BASK) modulation scheme was used. The relationship between the modulation scheme, data rate and bit error rate was also determined in the case of BASK. With the obtained studies, it make possible to provide valuable information for further studies on the selection of the modulation scheme and the real-time localization of the capsules.展开更多
A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the diffe...A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the difference in feature-point values that indicate biomedical signal characteristics. Furthermore, we propose a priority-adjustment method that enhances quality of service while guaranteeing signal integrity. A large number of simulations were carried out for performance evaluation. We use electrocardiogram and electromyogram signals as reference biomedical signals for performance verification. From the simulation results, we find that the average packet latency of proposed scheme is enhanced by 30% compared to conventional method. The simulation results also demonstrate that the proposed algorithm achieves significant performance improvement in terms of drop rates of high-priority packets around 0.3%-0.9 %.展开更多
This paper proposes an environment-aware best- retransmission count selected optimization control scheme over IEEE 802.11 multi-hop wireless networks. The proposed scheme predicts the wireless resources by using stati...This paper proposes an environment-aware best- retransmission count selected optimization control scheme over IEEE 802.11 multi-hop wireless networks. The proposed scheme predicts the wireless resources by using statistical channel state and provides maximum retransmission count optimization based on wireless channel environment state to improve the packet delivery success ratio. The media access control （MAC） layer selects the best-retransmission count by perceiving the types of packet loss in wireless link and using the wireless channel charac- teristics and environment information, and adjusts the packet for- warding adaptively aiming at improving the packet retransmission probability. Simulation results show that the best-retransmission count selected scheme achieves a higher packet successful delivery percentage and a lower packet collision probability than the corresponding traditional MAC transmission control protocols.展开更多
为提高OFDM(Orthogonal Frequency Division Multiplexing)系统通信衰落信道估计性能,提出一种基于深度神经网络的信道估计模型DeReNet。通过串联深度密集网络和深度残差网络,抑制网络训练中出现的梯度爆炸和消失问题。将该模型与LS(Lea...为提高OFDM(Orthogonal Frequency Division Multiplexing)系统通信衰落信道估计性能,提出一种基于深度神经网络的信道估计模型DeReNet。通过串联深度密集网络和深度残差网络,抑制网络训练中出现的梯度爆炸和消失问题。将该模型与LS(Least Square)、FC-DNN(Full Connection Dense Neural Network)和SimNet(Simplified Deep Neural Networks)模型进行仿真实验对比,结果表明,在莱斯衰落环境下该模型的信道估计性能更好,能有效提高信道衰落的估计精度。展开更多
随着移动通信技术的发展演进,6G(6th-Generation)网络作为新一代智能化数字信息基础设施,将不再仅聚焦信号的传输和复现,更需要基于电磁传播过程实现对周围环境的高效感知和理解,从而获取信道语义知识,协助智能通信体的预测、决策、波...随着移动通信技术的发展演进,6G(6th-Generation)网络作为新一代智能化数字信息基础设施,将不再仅聚焦信号的传输和复现,更需要基于电磁传播过程实现对周围环境的高效感知和理解,从而获取信道语义知识,协助智能通信体的预测、决策、波束成形等.因此,相较于传统信道而言,赋予无线信道模型对物理环境的语义理解、重构、表达能力,已成为智能无线信道模型的重要特征.本文提出了一种无线信道语义的分析和建模方法,将信道语义定义为状态语义、行为语义和事件语义3种层级,分别对应信道瞬态多径、信道时变轨迹和信道拓扑结构.此外,基于车载通感一体化(Integrated Sensing And Communication,ISAC)信道测量系统,开展了28 GHz下面向信道语义表征的无线信道测量,基于实测数据对信道语义进行解构、标识、建模,重点分析了3种不同语义下的信道多径分布特性,完成了语义导向的信道生成,结果表明信道语义模型能够在生成较准确信道的同时,表达更丰富的语义信息.本文工作是在语义层面上探索智能信道建模的新方法,通过深入挖掘无线信道的内在语义特征,促进通信系统在理解和认知环境方面的能力,从而提高通信效率和质量.展开更多
基金This project was supported by the key program of the National Natural Science Foundation of China (60432040).
文摘By exploring the deterministic characteristics of the measurement data, a new propagation model with two deterministic clusters and stochastic arriving rays within each cluster is proposed. When considering the cumulative distribution function （CDF） of the three key channel statistics, the proposed model fits the measurement data better than SV/IEEE 802.15.3, a model which is known as a standard model for UWB indoor propagation channel. Therefore, with the additional knowledge of the specific environment geometry, the proposed model generating impulse responses ＂resemble＂ the measured channel impulse responses better than IEEE model. Moreover, the proposed model＇s parameters obtaining procedure is simplified by utilizing simple parameters of the environment.
基金This project was supported by the Scientific Research Foundation of Harbin Institute of Technology (HIT. 2001.01).
文摘In wireless networks, packet access is a popular mode, and the key problem is how to improve throughput and access delay performance, especially the throughput for wireless channels. These results will be a reference for not only a wireless channel but also a common MAC protocol.
基金supported by the National Natural Science Foundation of China(61106022)the Beijing Natural Science Foundation(4143066)
文摘Wireless communication is easily disturbed by unfortunate factors which drive the wireless environment unstable and complicated. Therefore, it is essential to consider these factors in stability analysis of the wireless network. However, wireless channel characteristics and packets collisions are neglected in the classical fluid model. A wireless TCP fluid model （WTFM） for stability analysis of wireless network is proposed based on cross layers, which not only makes the congestion control based on random early detection （RED） available for wireless network, but also provides a more accurate model to analyze the stability of wireless system theoretically. In the proposed model, active queue management, abnormality of wireless channels and packets collisions are taken into consideration. The comparisons between evaluating results from the WTFM and the practical performance from NS2 simulations validate the accuracy of the proposed WTFM in the perspectives of delay, dropping probability, throughput, sliding window size and queue length. A set of comparisons among the proposed WTFM, the classical fluid model and the convex optimization model are conducted. The results demonstrate that the proposed WTFM model performs better than other schemes in comprehensive aspects on capturing the characteristic of the wireless network and computing complexity.
基金Projects(BK2011352,BK20131183) partially supported by the Natural Science Foundation of Jiangsu Province,ChinaProjects(SYG201011,SYG201211) supported by Suzhou Science and Technology Bureau,ChinaProject(10-03-16) supported by Xi’an Jiaotong-Liverpool University Research Development Fund,China
文摘Wireless capsule endoscopy(WCE) is a promising technique which has overcome some limitations of traditional diagnosing tools, such as the comfortlessness of the cables and the inability of examining small intestine section. However, this technique is still far from mature and asks for the feasible improvements. For example, the relatively low transmission data rate and the absence of the real-time localization information of the capsule are all important issues. The studies of them rely on the understanding of the electromagnetic wave propagation in human body. Investigation of performance of WCE communication system was carried out by studying electromagnetic(EM) wave propagation of the wireless capsule endoscopy transmission channel. Starting with a pair of antennas working in a human body mimic environment, the signal transmissions and attenuations were examined. The relationship between the signal attenuation and the capsule(transmitter) position, and direction was also evaluated. These results provide important information for real-time localization of the capsule. Moreover, the pair of antennas and the human body were treated as a transmission channel, on which the binary amplitude shift keying(BASK) modulation scheme was used. The relationship between the modulation scheme, data rate and bit error rate was also determined in the case of BASK. With the obtained studies, it make possible to provide valuable information for further studies on the selection of the modulation scheme and the real-time localization of the capsules.
基金supported by Inha University Research Grant,Korea
文摘A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the difference in feature-point values that indicate biomedical signal characteristics. Furthermore, we propose a priority-adjustment method that enhances quality of service while guaranteeing signal integrity. A large number of simulations were carried out for performance evaluation. We use electrocardiogram and electromyogram signals as reference biomedical signals for performance verification. From the simulation results, we find that the average packet latency of proposed scheme is enhanced by 30% compared to conventional method. The simulation results also demonstrate that the proposed algorithm achieves significant performance improvement in terms of drop rates of high-priority packets around 0.3%-0.9 %.
基金supported by the National Basic Research Program of China(2013CB329005)the National Natural Science Foundation of China(61101105+9 种基金6120116261302100)the Basic Research Program of Jiangsu Province(BK2011027BK2012434)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(12KJB51002212KJB510020)the Postdoctoral Science Foundation of China(2013M531391)the State Grid Project(52090F135015)the Scientific Research Foundation for Nanjing University of Posts and Telecommunications(NY211006NY211007)
文摘This paper proposes an environment-aware best- retransmission count selected optimization control scheme over IEEE 802.11 multi-hop wireless networks. The proposed scheme predicts the wireless resources by using statistical channel state and provides maximum retransmission count optimization based on wireless channel environment state to improve the packet delivery success ratio. The media access control （MAC） layer selects the best-retransmission count by perceiving the types of packet loss in wireless link and using the wireless channel charac- teristics and environment information, and adjusts the packet for- warding adaptively aiming at improving the packet retransmission probability. Simulation results show that the best-retransmission count selected scheme achieves a higher packet successful delivery percentage and a lower packet collision probability than the corresponding traditional MAC transmission control protocols.
文摘随着移动通信技术的发展演进,6G(6th-Generation)网络作为新一代智能化数字信息基础设施,将不再仅聚焦信号的传输和复现,更需要基于电磁传播过程实现对周围环境的高效感知和理解,从而获取信道语义知识,协助智能通信体的预测、决策、波束成形等.因此,相较于传统信道而言,赋予无线信道模型对物理环境的语义理解、重构、表达能力,已成为智能无线信道模型的重要特征.本文提出了一种无线信道语义的分析和建模方法,将信道语义定义为状态语义、行为语义和事件语义3种层级,分别对应信道瞬态多径、信道时变轨迹和信道拓扑结构.此外,基于车载通感一体化(Integrated Sensing And Communication,ISAC)信道测量系统,开展了28 GHz下面向信道语义表征的无线信道测量,基于实测数据对信道语义进行解构、标识、建模,重点分析了3种不同语义下的信道多径分布特性,完成了语义导向的信道生成,结果表明信道语义模型能够在生成较准确信道的同时,表达更丰富的语义信息.本文工作是在语义层面上探索智能信道建模的新方法,通过深入挖掘无线信道的内在语义特征,促进通信系统在理解和认知环境方面的能力,从而提高通信效率和质量.
