地铁信号系统通过无线基站进行数据传输和通信,为列车提供准确的位置和速度信息,指导列车的运行。射频拉远单元(Remote Radio Unit,RRU)是地铁信号系统的关键组成部分,需要稳定可靠的电源供应来确保正常运行。由于地铁环境复杂且具有高...地铁信号系统通过无线基站进行数据传输和通信,为列车提供准确的位置和速度信息,指导列车的运行。射频拉远单元(Remote Radio Unit,RRU)是地铁信号系统的关键组成部分,需要稳定可靠的电源供应来确保正常运行。由于地铁环境复杂且具有高度可靠性要求,RRU供电面临一系列挑战和限制。为提高地铁信号系统运行的稳定性,分析了RRU在地铁信号系统中的重要性,明确其在信息传输和信号稳定性方面的核心地位。接下来,针对现有供电模式中的局限性和存在的问题进行探讨,揭示了主要问题,如供电不稳定、能耗过高等。针对这些问题,进一步提出了有效的解决措施。展开更多
分布式设计已成为下一代大中型飞机设计热点,其中机载通信导航监视(Communication,Navigation and Surveillance,CNS)系统架构设计十分重要。为解决当前架构适航支持能力和新功能插入能力不强的问题,提出了分布式CNS系统的系统架构及系...分布式设计已成为下一代大中型飞机设计热点,其中机载通信导航监视(Communication,Navigation and Surveillance,CNS)系统架构设计十分重要。为解决当前架构适航支持能力和新功能插入能力不强的问题,提出了分布式CNS系统的系统架构及系统设计方法,并与联合式、集中式和分布式架构进行对比分析,得出分布式系统架构开放性和适航性好,具备优良的装机特性,可以为下一代机载CNS系统研制奠定基础。展开更多
This paper mainly introduces some related problems about special mobile communication signal based on TD-LTE and TD-SCDMA in high-speed railway, summaries the main difficulty of TD-LTE coverage in high-speed railway a...This paper mainly introduces some related problems about special mobile communication signal based on TD-LTE and TD-SCDMA in high-speed railway, summaries the main difficulty of TD-LTE coverage in high-speed railway and analyses TD & LTE wireless network coverage characteristics and key technologies under the environment of high-speed railway. First, we make a contrast of the coverage range of TD<E uplink and downlink in ordinary and special situations. Then we consider effective cover radius, the distance and grazing angle between stations and railway in 2G/3G/4G networks, calculate different distance between stations. Last, we did capacity planning for TD & LTE as telephone traffic throughput required in high-speed railway. The result shows that distance between stations is limited by LTE on sharing station address. Using single RRH with two antennas, the antenna height is 30m, and the speed of the train is 250 KM/h, the RRH distance among different cells can be 1177 m, and the RRH distance among same cells can be 1311 m. In the tunnel scene, the leakage cable cover is used and the station space distance of TD & LTE is 0.5 km. Tunnel station should move the switch belt to outdoors as much as possible without switching. This paper finished the link budget, protection distance measurement of cells and study of coverage method in the tunnel scene. The result helps guiding in planning, designing and optimizing for high-speed railway network in reality.展开更多
文摘地铁信号系统通过无线基站进行数据传输和通信,为列车提供准确的位置和速度信息,指导列车的运行。射频拉远单元(Remote Radio Unit,RRU)是地铁信号系统的关键组成部分,需要稳定可靠的电源供应来确保正常运行。由于地铁环境复杂且具有高度可靠性要求,RRU供电面临一系列挑战和限制。为提高地铁信号系统运行的稳定性,分析了RRU在地铁信号系统中的重要性,明确其在信息传输和信号稳定性方面的核心地位。接下来,针对现有供电模式中的局限性和存在的问题进行探讨,揭示了主要问题,如供电不稳定、能耗过高等。针对这些问题,进一步提出了有效的解决措施。
文摘分布式设计已成为下一代大中型飞机设计热点,其中机载通信导航监视(Communication,Navigation and Surveillance,CNS)系统架构设计十分重要。为解决当前架构适航支持能力和新功能插入能力不强的问题,提出了分布式CNS系统的系统架构及系统设计方法,并与联合式、集中式和分布式架构进行对比分析,得出分布式系统架构开放性和适航性好,具备优良的装机特性,可以为下一代机载CNS系统研制奠定基础。
文摘This paper mainly introduces some related problems about special mobile communication signal based on TD-LTE and TD-SCDMA in high-speed railway, summaries the main difficulty of TD-LTE coverage in high-speed railway and analyses TD & LTE wireless network coverage characteristics and key technologies under the environment of high-speed railway. First, we make a contrast of the coverage range of TD<E uplink and downlink in ordinary and special situations. Then we consider effective cover radius, the distance and grazing angle between stations and railway in 2G/3G/4G networks, calculate different distance between stations. Last, we did capacity planning for TD & LTE as telephone traffic throughput required in high-speed railway. The result shows that distance between stations is limited by LTE on sharing station address. Using single RRH with two antennas, the antenna height is 30m, and the speed of the train is 250 KM/h, the RRH distance among different cells can be 1177 m, and the RRH distance among same cells can be 1311 m. In the tunnel scene, the leakage cable cover is used and the station space distance of TD & LTE is 0.5 km. Tunnel station should move the switch belt to outdoors as much as possible without switching. This paper finished the link budget, protection distance measurement of cells and study of coverage method in the tunnel scene. The result helps guiding in planning, designing and optimizing for high-speed railway network in reality.
