随着物联网(IoT, internet of things)基站的部署愈发密集,网络干扰管控的重要性愈发凸显。物联网中,设备常采用随机接入,以分布式的方式接入信道。在海量设备的物联网场景中,节点之间可能会出现严重的干扰,导致网络的吞吐量性能严重下...随着物联网(IoT, internet of things)基站的部署愈发密集,网络干扰管控的重要性愈发凸显。物联网中,设备常采用随机接入,以分布式的方式接入信道。在海量设备的物联网场景中,节点之间可能会出现严重的干扰,导致网络的吞吐量性能严重下降。为了解决随机接入网络中的干扰管控问题,考虑基于协作接收的多基站时隙Aloha网络,利用强化学习工具,设计自适应传输算法,实现干扰管控,优化网络的吞吐量性能,并提高网络的公平性。首先,设计了基于Q-学习的自适应传输算法,通过仿真验证了该算法面对不同网络流量时均能保障较高的网络吞吐量性能。其次,为了提高网络的公平性,采用惩罚函数法改进自适应传输算法,并通过仿真验证了面向公平性优化后的算法能够大幅提高网络的公平性,并保障网络的吞吐性能。展开更多
This article is about orthogonal frequency-division multiplexing with quadrature amplitude modulation combined with code division multiplexing access for complex data transmission. It aims to present a method which us...This article is about orthogonal frequency-division multiplexing with quadrature amplitude modulation combined with code division multiplexing access for complex data transmission. It aims to present a method which uses two interfering subsets in order to improve the performance of the transmission scheme. The idea is to spread in a coherent manner some data amongst two different codes belonging to the two different subsets involved in complex orthogonal frequency-division multiplexing with quadrature amplitude modulation and code division multiplexing access. This will improve the useful signal level at the receiving side and therefore improve the decoding process especially at low signal to noise ratio. However, this procedure implies some interference with other codes therefore creating a certain noise which is noticeable at high signal to noise ratio.展开更多
鞋履时尚品牌ALOHAS委托设计工作室Clap Studio为其设计在巴塞罗那的首家旗舰店,店铺位于城市中心标志性的Rambla de Catalunya大街。这家100 m2的旗舰店忠实反映了ALOHAS全新的视觉识别系统,展现出更强烈、更大胆的美学风格。通过这家...鞋履时尚品牌ALOHAS委托设计工作室Clap Studio为其设计在巴塞罗那的首家旗舰店,店铺位于城市中心标志性的Rambla de Catalunya大街。这家100 m2的旗舰店忠实反映了ALOHAS全新的视觉识别系统,展现出更强烈、更大胆的美学风格。通过这家旗舰店,ALOHAS在征服线上渠道之后,迈出了向线下商业进军的重要一步。展开更多
A new acknowledgment-type slotted-ALOHA code division multiple access （ACK-ALOHA-CDMA） channel which can be used in the inbound channels of very small aperture terminal（VSAT） networks is proposed in order to simpl...A new acknowledgment-type slotted-ALOHA code division multiple access （ACK-ALOHA-CDMA） channel which can be used in the inbound channels of very small aperture terminal（VSAT） networks is proposed in order to simplify the synchronization equipment of networks in the slotted-ALOHA- CDMA systems. By dividing all VSAT stations into M subsystems and sending out periodic inquiry signals from the Hub station to the VSAT station, the channel model is established. By the means of deriving multi-access interference（MAI） and packet detecting probability, steady-state throughput is calculated. By applying diffusion process theory to the analysis of the stability of the ACK-ALOHA-CDMA channel, the drift parameter a（r）, the diffusion parameter b（r） and the steady transition probability density p （r） are investigated. Simulation results indicate that significant performance improvement and high-bandwidth efficiency can be gained and one or two steady equilibrium points can be obtained by using this channel. Consequently, the ACK- ALOHA-CDMA channel is very suitable for cutting down on the expense of satellite VSAT systems and distributed packet radio networks.展开更多
文摘随着物联网(IoT, internet of things)基站的部署愈发密集,网络干扰管控的重要性愈发凸显。物联网中,设备常采用随机接入,以分布式的方式接入信道。在海量设备的物联网场景中,节点之间可能会出现严重的干扰,导致网络的吞吐量性能严重下降。为了解决随机接入网络中的干扰管控问题,考虑基于协作接收的多基站时隙Aloha网络,利用强化学习工具,设计自适应传输算法,实现干扰管控,优化网络的吞吐量性能,并提高网络的公平性。首先,设计了基于Q-学习的自适应传输算法,通过仿真验证了该算法面对不同网络流量时均能保障较高的网络吞吐量性能。其次,为了提高网络的公平性,采用惩罚函数法改进自适应传输算法,并通过仿真验证了面向公平性优化后的算法能够大幅提高网络的公平性,并保障网络的吞吐性能。
文摘This article is about orthogonal frequency-division multiplexing with quadrature amplitude modulation combined with code division multiplexing access for complex data transmission. It aims to present a method which uses two interfering subsets in order to improve the performance of the transmission scheme. The idea is to spread in a coherent manner some data amongst two different codes belonging to the two different subsets involved in complex orthogonal frequency-division multiplexing with quadrature amplitude modulation and code division multiplexing access. This will improve the useful signal level at the receiving side and therefore improve the decoding process especially at low signal to noise ratio. However, this procedure implies some interference with other codes therefore creating a certain noise which is noticeable at high signal to noise ratio.
文摘鞋履时尚品牌ALOHAS委托设计工作室Clap Studio为其设计在巴塞罗那的首家旗舰店,店铺位于城市中心标志性的Rambla de Catalunya大街。这家100 m2的旗舰店忠实反映了ALOHAS全新的视觉识别系统,展现出更强烈、更大胆的美学风格。通过这家旗舰店,ALOHAS在征服线上渠道之后,迈出了向线下商业进军的重要一步。
基金The Key Laboratory Foundation of Geographical Information Science of Jiangsu Province (No.JK20050304)the Key Laboratory Foundation of Virtual Geographical Environments of Ministry of Education(No.NS206005)
文摘A new acknowledgment-type slotted-ALOHA code division multiple access （ACK-ALOHA-CDMA） channel which can be used in the inbound channels of very small aperture terminal（VSAT） networks is proposed in order to simplify the synchronization equipment of networks in the slotted-ALOHA- CDMA systems. By dividing all VSAT stations into M subsystems and sending out periodic inquiry signals from the Hub station to the VSAT station, the channel model is established. By the means of deriving multi-access interference（MAI） and packet detecting probability, steady-state throughput is calculated. By applying diffusion process theory to the analysis of the stability of the ACK-ALOHA-CDMA channel, the drift parameter a（r）, the diffusion parameter b（r） and the steady transition probability density p （r） are investigated. Simulation results indicate that significant performance improvement and high-bandwidth efficiency can be gained and one or two steady equilibrium points can be obtained by using this channel. Consequently, the ACK- ALOHA-CDMA channel is very suitable for cutting down on the expense of satellite VSAT systems and distributed packet radio networks.
