At present, in the GSM network construction and maintenance work, how to solve the capacity and interference problems of the high traffic density area of ​​the GSM network, improve the connection rate of the whole network, reduce the call drop rate and improve the call quality, has become the focus of recent work and difficulty. The use of suitable antenna technology will be one of the methods to effectively control the coverage, reduce co-channel interference and improve the reception of mobile phone signals. The dual-polarized antenna is a new type of antenna technology. It combines two antennas with orthogonal directions of +45° and -45°, and works in transceiver duplex mode. Only one pair of dual-polarized antennas is needed in each cell. . When the omnidirectional cell is split into three cells, at most one antenna is added (the original omnidirectional cell is 2 antennas in the duplex mode). In the conventional single-polarized antenna, when the omni-directional cell is split into three cells, the number of antennas increases sharply (even at least in the duplex mode), due to the inter-antenna (RX-TX, TX-TX). Isolation (≥30dB) and space diversity techniques require horizontal and vertical separation distances between antennas. At this time, the platform on which the antennas are installed must be enlarged, which increases infrastructure investment. In the dual-polarized antenna, the polarization orthogonality of ±45° ensures that the isolation between the two antennas of +45° and -45° satisfies the inter-pair isolation requirement (≥30dB), and the dual-polarized antenna The space interval between them is only 20 to 30 cm. Therefore, the mobile base station does not need to build an iron tower. It only needs to mount an iron column with a diameter of 20 cm, and the dual-polarized antenna can be fixed on the iron column in the corresponding covering direction. Especially when selecting a site, if a conventional single-polarized antenna is used, the installation and installation of the antenna must be considered, and the optimal site is often abandoned due to the lack of possession of the antenna mounting conditions (the need to build an iron tower to expand the antenna platform). If a dual-polarized antenna is used, since the dual-polarized antenna has low requirements for erection and installation, it is not necessary to build a tower for land acquisition, which saves capital investment and makes the base station layout more reasonable. The dual-polarized antenna allows the system to adopt polarization diversity reception technology. The principle is to use the irrelevance between the polarization directions of ±45°. The degree of irrelevance between the two determines the quality of diversity reception. Since ±45° is orthogonally polarized, diversity reception can be effectively ensured, and its polarization diversity gain is about 5 dB, which is about 2 dB higher than that of a single-polarized antenna. In addition, the spatial diversity reception effect of the single-polarized antenna is related to the position of the two receiving antennas, and the positive direction of the antenna coverage is optimal, and gradually weakens to both sides, resulting in a narrow coverage of the actual coverage of the cell. Polarization diversity is used instead of spatial diversity. The diversity gain has little to do with the antenna position. The difference between the main direction and the edge is small (this difference is caused by the ±45° orthogonal effect due to the width of the reflection surface), so it can be effective. Improve the reception at the edge and ensure coverage. In order to limit the signal to the coverage of the serving cell and reduce the interference to other co-frequency cells, the vertical tilting of the antenna is a more effective antenna technology. The function can make the coverage of the cell smaller, strengthen the signal strength in the coverage area, increase the anti-interference interference capability, reduce the gain of the antenna in the interference direction, and reduce the interference of other co-frequency cells; select a suitable downtilt angle The ray with the antenna to the boundary of the cell and the ray of the antenna to the boundary of the interfered cell can be in the portion where the gain attenuation changes the most in the vertical direction, thereby minimizing the co-channel interference of the interfered cell. Generally, the mechanical downtilt and the electronic downtilt are used to realize the downward tilting of the antenna. (1) The mechanical downtilt is to physically tilt the antenna downward. Although this technique can also reduce the same-frequency interference, its construction and maintenance are very troublesome due to the physical downtilt, and its accuracy of adjusting the tilt angle is low (step accuracy is 1°). In addition, since the downtilt angle is the theoretical value of the simulation calculation software, there is a certain deviation from the theoretical optimal value. In the network adjustment, the base station system must be shut down first, and the adjustment effect cannot be monitored simultaneously in the adjustment antenna. It is impossible to finely adjust the network. (2) The electronic downtilt is to change the phase of the collinear array antenna vibrator, change the amplitude of the vertical component and the horizontal component, change the intensity of the composite component field strength, and tilt the vertical directional pattern of the antenna. Since the field strength of each direction of the antenna increases and decreases at the same time, it is ensured that the antenna pattern changes little after changing the tilt angle, so that the coverage distance of the main lobe direction is shortened, and the entire directional pattern is reduced in the serving cell sector. Coverage area without interference. The adjustable electronic downtilt antenna allows the tilting angle adjustment of the vertical directional pattern without stopping the system, real-time monitoring and adjustment effect, and the stepping accuracy of adjusting the tilt angle is also high (0.1°), so it can be implemented on the network. Fine adjustment. After the antenna is tilted down, the coverage edge area is deviated from the main lobe of the antenna, which reduces the signal strength, which can be compensated by reasonably increasing the transmitter power. At present, user complaints in the mobile network are concentrated in the high-density traffic area. The low connection rate and high call loss actually reflect the insufficient capacity and the same frequency interference in the high traffic area. In order to solve the shortage of capacity in the high traffic area, the station distance must be shortened, and the antenna downtilt angle is increased to help narrow the coverage and reduce the same frequency interference. However, the antenna should be tilted at an appropriate angle. If the tilt angle is too large, the antenna pattern will be severely deformed. To control the coverage and reduce the same frequency interference, it is counterproductive; if the downtilt angle is too small, it will not work. Therefore, it is difficult to solve the problem of low connection rate and high call drop rate in the high traffic area by using the mechanical downtilt mode. Only the adjustable electronic downtilt antenna technology can solve the problem in the high traffic area. This paper analyzes the influence of the dual-polarized antenna and its directional pattern down-tilt technology on the network. Compared with traditional single-polarized antennas, dual-polarized antenna technology has the advantages of saving antennas, reducing capital investment, low site requirements and high receive diversity gain. Electronic downtilt technology is more accurate than mechanical downtilt technology. At the same time, the adjustable electronic downtilt technology can monitor and adjust the wireless network coverage in real time, so that the wireless network tends to be fine, can effectively control the wireless coverage, strengthen the signal of the serving cell, and reduce the same-frequency interference. Therefore, in the future application of antenna technology, in the dense traffic area where the base station is dense, the dual-polarized antenna and the adjustable electronic down-tilt technology should be used as much as possible, and the traffic in the border and suburbs is not high, the base station is not dense, and only Requires coverage area, you can still use traditional single-polarized antenna and mechanical down-tilt technology. Fiber Optic Box,Fiber Optics Box,Fiber Optic Boxes,Fiber Optic Junction Box Cixi Dani Plastic Products Co.,Ltd , https://www.dani-fiber-optic.com