Shulou(Shulou.com)06/03 Report--

What's the difference between macro base station and micro base station? I believe that many inexperienced people are at a loss about this, so this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

The difference between macro base station and micro base station: macro base station is a straight point, tower station, larger kind, a station covers dozens of kilometers, complete computer room facilities, micro base station is a small base station installed in buildings or dense areas, with small coverage and low number of users. cover a single village, building and other scenes.

Base station composition

infrastructure

Communication base station is the most critical infrastructure in mobile communication network. The base station is mainly equipped with signal transceivers, monitoring devices, fire extinguishing devices, power supply equipment and air-conditioning equipment, as well as towers including lightning protection grounding system, tower body, foundation, support, cable and auxiliary facilities. According to the shape, the tower mast can be divided into many different forms, such as angle steel tower, single tube tower, ejector pole, cable tower and so on. The antenna is a three-layer structure of antenna frame, feed system and infinite reflector, which has two different application scenarios, indoor and outdoor. According to different transmission directions, antennas can also be divided into directional and omni-directional.

The selection of a base station needs to be comprehensively considered from the aspects of performance, matching, compatibility and use requirements, among which it is paid special attention to that the base station equipment must be compatible or matching with the mobile switching center in order to achieve better communication results. The base station subsystem mainly includes two types of equipment: base station transceiver station (BTS) and base station controller (BSC).

Base station location selection

The location of the base station must first consider the communication environment around the communication base station, comprehensively consider the base station density, signal, traffic volume, site conditions and other factors, try to avoid strong electromagnetic interference, pulse interference areas and a large number of combustibles and explosive products commercial, near the warehouse. In addition, the communication base station should be built in an open field of vision, and there should be no tall buildings around to prevent the signal transmission of the communication base station. In the process of base station communication construction, the construction of computer room, the installation of equipment and the construction of tower are all mechanical structures. The construction machinery and technical level are very high. The geographical characteristics of the construction area should be investigated before construction, so as to make full use of favorable topographic conditions to facilitate construction and maintenance.

Tower selection

The selection of the tower must first consider the geological conditions of the construction area, build the pile foundation scientifically, and select the appropriate tower type on this basis. Before formally carrying out the design and implementation of the tower selection of the communication base station, it is necessary to conduct a comprehensive investigation of the geological conditions of the construction area to understand the geological conditions and possible geological risks of the construction area. On this basis, a series of effective methods are given. Response measures, select the appropriate tower type, comprehensively check the economic, technical and safety indicators, and select the appropriate tower form. For the pile communication base station, the selection of the tower must first consider the performance, crack resistance and settlement of the pile, and analyze and verify these performance indicators. The whole load of the communication tower is basically directly applied to the foundation. In order to improve the stability of the tower, special attention must be paid to the foundation construction. There are three different forms of tower foundation construction: extended foundation, single pile foundation and group pile foundation. When necessary, tie beams and anchor bolts can be added, and the liquefaction treatment of the foundation can be resisted, so as to further improve the bearing capacity of the foundation.

Transceiver station

We often see the high antenna on the roof, which is part of the base station transceiver. A complete base station transceiver includes wireless transmitting / receiving equipment, antennas and signal processing parts specific to all wireless interfaces. The base station transceiver can be regarded as a wireless modem, which is responsible for the reception and transmission of mobile signals. In general, in a certain area, multiple sub-base stations and transceiver stations form a cellular network to achieve the transmission of mobile communication signals by controlling the mutual transmission and reception of signals between the transceiver and the transceiver station. the area within this range is what we often call network coverage. If there is no transceiver, it is impossible to send and receive mobile phone signals. The area that cannot be covered by the base station transceiver is the blind area of the mobile phone signal. Therefore, the range of signals transmitted and received by the base station transceiver station is directly related to the quality of the network signal and whether the mobile phone can be used normally in this area.

Under the control of the base station controller, the base station transceiver station completes the conversion between the base station control and the wireless channel, and realizes the wireless transmission and related control functions between the mobile communication signal transceiver and the mobile platform. The transceiver can decode and transmit the wireless signal of each user.

The antenna used by the base station is divided into transmitting antenna and receiving antenna, and there are omni-directional and directional. Generally, there are three configuration modes: sending omni-directional and receiving omni-directional mode; sending omni-directional mode and receiving directional mode; sending directional mode and receiving directional mode. Literally we can understand the difference of each way, sending omni-directional is mainly responsible for omni-directional signal transmission; receiving omni-directional nature is an azimuth receiving signal; orientation means sending and receiving only to a fixed angle. In general, the base stations with fewer channels (such as located in the suburbs) often use omni-directional transmission and receiving omni-directional mode, while the base stations with more channels adopt the way of sending omni-directional and receiving orientation, and the establishment of base stations is more intensive than that in the suburbs.

As the signal transmission to the base station may be relatively weak, and there is a certain signal interference, so it has to go through the preselector.

Module filtering and amplification, double frequency conversion, amplification and frequency discrimination processing. The input high frequency signal is amplified and sent to the first frequency converter, and the frequency of the first local oscillation signal provided by the frequency converter is 766.9125-791.8875MHz. After down conversion, the first intermediate frequency signal of 123.1MHz is generated. The first intermediate frequency signal is amplified, filtered and mixed to generate a second intermediate frequency signal (21.3875MHz), which is amplified and filtered and sent to the intermediate frequency integrated block. The audio output signal and the received signal strength indication signal (RSSI) generated by the if integrated block (including a second if signal amplifier, a limiter and a frequency discriminator) are sent to the audio / control board. In the audio signal control board, the odd and even signals are continuously compared by the diversity switch, and the stronger signals are selected and transmitted to the mobile control center through the audio circuit.

The working principle of the base station transmitter is as follows: the carrier frequency signal of 766.9125-791.8875MHz provided by the frequency synthesizer and the modulated signal of 168.1MHz are filtered into the double balanced frequency converter respectively, and the radio frequency signal with the frequency of 935.0125-959.9875MHz is obtained. After filtering and amplification, the radio frequency signal enters the driver stage, and the output power of the driver stage is about 2.4 W, and then added to the power amplifier module. The power control circuit uses negative feedback technology to automatically adjust the output power of the front drive stage or drive stage to keep the output power of the drive stage at the rated value. That is, the received signal is stabilized and then sent out, which can effectively reduce or avoid the loss of communication signal in wireless transmission and ensure the communication quality of users. The function of the power amplifier module is to amplify the signal to 10W, but it also depends on the actual situation. If the radius of the transmitted signal in the cell is large, 25W or 40W power amplifier module can be used to enhance the transmission radius of the signal.

Controller

The base station controller includes wireless transceiver, antenna and related signal processing circuit, which is the control part of the base station subsystem. It mainly includes four components: cell controller (CSC), voice channel controller (VCC), signaling channel controller (SCC) and multiplex interface (EMPI) for expansion. A base station controller usually controls several base station transceiver stations. Through the remote commands of the transceiver station and the mobile station, the base station controller is responsible for all the mobile communication interface management, mainly the allocation, release and management of the wireless channel. When you use a mobile phone, it is responsible for opening a signal channel for you, and at the end of the call, it closes the channel for others to use. In addition, the handoff of the mobile station in the control area is also controlled. If you enter the signal receiving and receiving range of another base station when using your mobile phone, the controller is responsible for switching between another base station and maintaining the connection with the mobile switching center all the time.

When the GSM system crosses the zone, it adopts the handover mode, that is, when the user reaches the boundary of the cell, the mobile phone will first cut off the contact with the original base station, and then establish contact with the base station of the new service district. When the new service district is busy, the call channel can not be provided, and then the phenomenon of disconnection will occur. Therefore, when talking on a mobile phone, users should try their best to avoid using it in the four-corner blind area, so as to reduce the probability of dropping the call.

The core of the controller is the switched network and the common processor (CPR). The common processor controls and manages the internal modules of the controller and connects with the operation and maintenance center (OMC) through the X.25 communication protocol. The switching network will complete the internal exchange of 64kbit/s data / voice traffic channels between the interface and the interface. The controller is connected to the mobile switching center through the interface device digital repeater (DTC) and to the transceiver station through the interface equipment terminal controller (TCU) to form a simple communication network.

In the whole cellular mobile communication system, the base station subsystem is the bridge between the mobile station and the mobile center, and its position is extremely important. The communication quality of the whole cellular system is determined by the number of base stations in the whole coverage area, the position of the base stations in the cellular cell, and the performance of the related components in the base station subsystem. The selection and construction of base stations has become an important part of the establishment of modern mobile communication network.

After reading the above, do you know the difference between macro base station and micro base station? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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