The base transceiver station
I'll tell you about the base stations (BS, BTS) of Huawei, with which I have the honor to work.
Base transceiver station (BTS) is one of the components that make up the radio equipment of the base station subsystem (BSS).
As can be seen, the BTS is a transceiver equipment serving a specific cell under the control of a BSC (base station controller).
BTS performs protocol conversion between radio channels (which are used for communication between a mobile station and a base station - the so-called Um interface) and between wired channels (communication between the BTS and BSC - Abis interface).
Speaking in more detail, BTS performs the following functions:
-Providing communication interface with BSC;
-Management of radio channels;
- Management function and maintenance;
-A signaling protocol processing function.
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There are several BS series:
1) high capacity internal performance
The cabinet of such a base station in its full configuration contains 12 TRX (transceivers);
2) microcellular BTS equipment series
They are mainly used in crowded places, such as office buildings, department stores and sports venues;
3) a series of equipment BTS external performance
Suitable for use in remote areas;
4) BTS series of container type;
Equipment BTS of this type is a fully equipped room.
BTS consists of a common unit (control and communication unit), a unit of carrier frequencies and an antenna-feeder system.
BTS equipment block diagram
Picture of the main cabinet
Consider the functions performed by each block:
• Common unit
It consists of a synchronization / transmission unit and control unit (TMU), a synchronization distribution unit (TDU), an additional transmission unit (TEU), an additional transmission unit power supply unit (TES), a fan operation monitoring unit (FMU), a power supply unit (PSU), a unit power and environmental monitoring (PMU), power distribution unit (SWITCH BOX), fan unit (FAN BOX) and air intake (AIR BOX).
1) The synchronization / transmission and control unit (TMU) is the main component of the BTS. Its functions are BTS synchronization, transmission over the Abis interface and base station control. One TMU board is equipped with 4 E1 interfaces.
2) A synchronization distribution unit (Time distributing unit - TDU), whose main function is to receive a clock signal, process it and control BTS synchronization.
3) An additional transmission unit (Transmission extension unit - TEU) is a built-in transmission capacity extension unit for BTS.
4) An additional transmission unit (TES) power unit provides power to the TEU.
5) The fan condition monitoring unit (FMU) is located on the fan shelf (FAN BOX) and controls the operation of two fans of this shelf and issues alarms.
6) The power supply unit (PSU) is a power supply module built into the BTS that provides two types of conversion - converting alternating current into direct current and converting the level of direct current voltage (DC / DC).
7) The Power and Environmental Monitoring Unit (PMU) is responsible for managing the power supply and monitoring 24 digital and 8 analog parameters.
8) The power distribution unit (SWITCH BOX) distributes the supply voltage to all the boards.
9) Air intake (AIR BOX) provides cooling equipment.
• Carrier frequency block
BTS equipment has a modular structure, that is, all units (low frequency signal processing unit, RF unit, power supply unit), providing reception and transmission at a certain carrier frequency (carrier), integrated into one removable module - TRX. It receives a variety of management and configuration information from the TMU, sending back various status information and alarms to it. From the Um interface in the opposite direction (up-link), the TRX receives a radio signal from the mobile station (via the antenna and CDU), then demodulates this signal, divides it into voice and signal information, and sends it further (in the BSC direction). In the forward direction (down-link), the speech and signal information after processing on the TRX as a single signal is transmitted to the CDU and then through the antenna to the mobile station.
• Antenna-feeder system
Antenna-feeder base station system consists of an antenna, feeder, adapters, lightning protection device, and a tower top amplifier installed at will. The main function of AFS is to transmit modulated radio signals and receive signals from a mobile station, as well as issue an alarm.
An antenna is characterized by power (ability by radiation in a certain direction), directivity (describes the direction of radiation), polarization (describes the plane of oscillations of an electromagnetic wave). To reduce transmission losses, cables with low attenuation in the radio band (feeder) are used. To prevent the influence of atmospheric discharge on the center conductor of the feeder, use a lightning protection device.
The CDU combines and filters the signal in the transmission, as well as filtering, amplifying and distributing the signal at the reception. In addition, it provides power to the mast amplifier DC.
I hope I managed to bring some clarity to the structural feature of the base station. It was only a superficial consideration, because Each block has its own functional and structural features that you cannot write about in one article.
Base transceiver station (BTS) is one of the components that make up the radio equipment of the base station subsystem (BSS).
As can be seen, the BTS is a transceiver equipment serving a specific cell under the control of a BSC (base station controller).
BTS performs protocol conversion between radio channels (which are used for communication between a mobile station and a base station - the so-called Um interface) and between wired channels (communication between the BTS and BSC - Abis interface).
Speaking in more detail, BTS performs the following functions:
-Providing communication interface with BSC;
-Management of radio channels;
- Management function and maintenance;
-A signaling protocol processing function.
')
There are several BS series:
1) high capacity internal performance
The cabinet of such a base station in its full configuration contains 12 TRX (transceivers);
2) microcellular BTS equipment series
They are mainly used in crowded places, such as office buildings, department stores and sports venues;
3) a series of equipment BTS external performance
Suitable for use in remote areas;
4) BTS series of container type;
Equipment BTS of this type is a fully equipped room.
BTS consists of a common unit (control and communication unit), a unit of carrier frequencies and an antenna-feeder system.
BTS equipment block diagram
Picture of the main cabinet
Consider the functions performed by each block:
• Common unit
It consists of a synchronization / transmission unit and control unit (TMU), a synchronization distribution unit (TDU), an additional transmission unit (TEU), an additional transmission unit power supply unit (TES), a fan operation monitoring unit (FMU), a power supply unit (PSU), a unit power and environmental monitoring (PMU), power distribution unit (SWITCH BOX), fan unit (FAN BOX) and air intake (AIR BOX).
1) The synchronization / transmission and control unit (TMU) is the main component of the BTS. Its functions are BTS synchronization, transmission over the Abis interface and base station control. One TMU board is equipped with 4 E1 interfaces.
2) A synchronization distribution unit (Time distributing unit - TDU), whose main function is to receive a clock signal, process it and control BTS synchronization.
3) An additional transmission unit (Transmission extension unit - TEU) is a built-in transmission capacity extension unit for BTS.
4) An additional transmission unit (TES) power unit provides power to the TEU.
5) The fan condition monitoring unit (FMU) is located on the fan shelf (FAN BOX) and controls the operation of two fans of this shelf and issues alarms.
6) The power supply unit (PSU) is a power supply module built into the BTS that provides two types of conversion - converting alternating current into direct current and converting the level of direct current voltage (DC / DC).
7) The Power and Environmental Monitoring Unit (PMU) is responsible for managing the power supply and monitoring 24 digital and 8 analog parameters.
8) The power distribution unit (SWITCH BOX) distributes the supply voltage to all the boards.
9) Air intake (AIR BOX) provides cooling equipment.
• Carrier frequency block
BTS equipment has a modular structure, that is, all units (low frequency signal processing unit, RF unit, power supply unit), providing reception and transmission at a certain carrier frequency (carrier), integrated into one removable module - TRX. It receives a variety of management and configuration information from the TMU, sending back various status information and alarms to it. From the Um interface in the opposite direction (up-link), the TRX receives a radio signal from the mobile station (via the antenna and CDU), then demodulates this signal, divides it into voice and signal information, and sends it further (in the BSC direction). In the forward direction (down-link), the speech and signal information after processing on the TRX as a single signal is transmitted to the CDU and then through the antenna to the mobile station.
• Antenna-feeder system
Antenna-feeder base station system consists of an antenna, feeder, adapters, lightning protection device, and a tower top amplifier installed at will. The main function of AFS is to transmit modulated radio signals and receive signals from a mobile station, as well as issue an alarm.
An antenna is characterized by power (ability by radiation in a certain direction), directivity (describes the direction of radiation), polarization (describes the plane of oscillations of an electromagnetic wave). To reduce transmission losses, cables with low attenuation in the radio band (feeder) are used. To prevent the influence of atmospheric discharge on the center conductor of the feeder, use a lightning protection device.
The CDU combines and filters the signal in the transmission, as well as filtering, amplifying and distributing the signal at the reception. In addition, it provides power to the mast amplifier DC.
I hope I managed to bring some clarity to the structural feature of the base station. It was only a superficial consideration, because Each block has its own functional and structural features that you cannot write about in one article.
Source: https://habr.com/ru/post/96179/
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