FA/D dual-frequency independent electric adjustable antenna cracks TD-LTE antenna deployment problem
Since 2013, the global TD-LTE network has entered a period of vigorous development, and the deployment and development of domestic TD-LTE networks are also in full swing. Currently deployed in China, TD-LTE mainly uses the most advanced 8-channel technology in the world, and the impact of antennas on network performance is getting more and more attention. This paper summarizes and analyzes the problems in the first phase of TD-LTE deployment, and combines the latest developments in the current antenna industry to provide some new ideas for the deployment and selection of subsequent TD-LTE antennas. According to statistics, in China's large and medium-sized cities, due to property coordination, site and other issues, more than 50% of the sites are difficult to add antennas. At the same time, when building the FA band, it is necessary to consider both the D-band and avoid the need for the subsequent D-band construction. The antenna is adjusted. Therefore, in the first phase of TD-LTE construction, a large number of FA/D dual-band built-in non-electrical adjustment antennas are used, that is, the FA and D bands adopt the same fixed built-in electric downtilt angle, and the downtilt angle is adjusted. The mechanical downtilt is completed. Theoretical analysis and actual tests show that the FA/D dual-band built-in combined antenna will have a huge impact on network performance. The specific analysis is as follows: 1. FA frequency band and D frequency band cannot be independently optimized and adjusted, resulting in a sharp decline in network performance. Due to the different wireless propagation performance of the FA and D bands, at the same downtilt angle, for the same transmit power, the difference between the electrical average and the D-band of the outdoor FA band is about 2 dB, and the difference between the indoor electrical averages is about 4-6 dB. When feeding, the optimal downtilt angle of the FA band and the D band are about 2 degrees. If the same downtilt angle is used, the network performance will drop drastically. According to the survey data of a city in TD-LTE Phase I, 68% of the FA and D-band co-site construction antenna downtilt needs to be adjusted in the engineering optimization, otherwise the performance will drop by 35%. Second, the mechanical downturn causes adjacent area interference, reduces the user experience at the edge of the cell, and the optimization efficiency is low. The FA/D dual-frequency built-in non-electrical adjustment antenna can only adjust the downtilt angle by mechanical downtilt. In the case of mechanical downtilt, the antenna pattern is not proportionally changed, by comparing the mechanical downtilt and the electrical downtilt antenna pattern projection. It can be seen that the mechanical downtilt adjustment causes the distortion of the lobe, which easily causes interference to adjacent cells. At the same time, it is only possible to adjust the mechanical support to the site, resulting in high labor costs on the station, difficulty in coordination of the inbound property, and low optimization efficiency. In response to the above problems, the FA/D dual-frequency independent electrical tune antenna has been introduced in the industry. The comparison test results of the antenna on the live network show that the above problems can be effectively solved. The verification conclusions are as follows: 1. The performance of the FA/D dual-frequency independent electrical adjustment antenna is 16% higher than that of the FA/D integrated non-electrical adjustment antenna, which is equivalent to the performance of the independent antenna networking. Test method: Keep the same engineering parameters (base station configuration, antenna hanging height, etc.) in different networking modes, only replace the antenna Test Results: 1. FA/D dual-band independent ESC network is compared with FA/D built-in non-electrical adjustment network, and the average downlink throughput is increased by 16%. 2. The average downlink throughput of the FA/D dual-frequency independent ESC network is comparable to that of the independent FAD broadband network. Second, the FA/D independent electrical tune antenna improves the cell edge throughput by 28% compared to the FA/D built-in non-electrical adjustment antenna. Test method: Select two cell overlap areas, and compare the performance of FA/D independent ESC antenna and FA/D built-in non-electrical adjustment antenna at the edge of the network under the same total downtilt angle. The test results show that the FA/D independent electrical tune antenna is far superior to the traditional mechanical downtilt antenna in the case of large downtilt, and the average cell edge throughput is increased by 28%. It can be seen that compared with the FA/D built-in non-electrical adjustment antenna, the FA/D dual-frequency independent electrical adjustment antenna can effectively improve the performance of the TD-LTE network, and the performance of the independent sky surface is equivalent, and the antenna management efficiency is higher. The FA/D built-in non-electrical adjustment antenna can not be independently adjusted and optimized due to the downtilt angle, and the distortion caused by the mechanical downturn causes the performance of the TD-LTE network to decrease. The performance of the current FA/D dual-band independent electrical tune antenna has been fully verified on the live network, and many antenna manufacturers have already launched related products. Based on this, it is recommended to limit the space in the sky or build the FA band, and consider both the D band. In the case of the FA/D dual-frequency independent electrical adjustment antenna, the FA/D built-in combined antenna is completely replaced. Electric Fan referred to as fan, also known as fan, fan fan, is a motor-driven fan rotation, to achieve the air to speed up the flow of household appliances, mainly for cool Jieshu and circulation of air. Widely used in homes, classrooms, offices, shops, hospitals and hotels and other places. Electric Fan Portable Fan, Electric Cooling Fans, Electric Stand Fan, Electric Wall Fan Ningbo APG Machine(appliance)Co.,Ltd , http://www.apgelectrical.com
The fan is mainly composed of fan head, fan blade, net cover and control device and other components. Fan includes motor, front and rear cover and shaking head blowing mechanism. The main components of the fan are: AC motor. Its working principle is: power coil in the magnetic field in the force and rotation. Electric energy into mechanical energy, and because of the coil resistance, so inevitably part of the energy to be converted into heat.
Common household fans are essentially axial fans, that is, the flow of wind parallel to the fan axis of rotation.