A base transceiver station (BTS) is a piece of equipment that facilitates
wireless communication
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
between
user equipment In the Universal Mobile Telecommunications System (UMTS) and 3GPP Long Term Evolution (LTE), user equipment (UE) is any device used directly by an end-user to communicate. It can be a hand-held telephone, a laptop computer equipped with a mobile bro ...
(UE) and a network. UEs are devices like
mobile phones (handsets),
WLL phones, computers with
wireless Internet
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
connectivity, or antennas mounted on buildings or telecommunication towers.
The network can be that of any of the wireless communication technologies like
GSM
The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such as ...
,
CDMA
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication ...
,
wireless local loop
Wireless local loop (WLL), is the use of a wireless communications link as the " last mile / first mile" connection for delivering plain old telephone service (POTS) or Internet access (marketed under the term "broadband") to telecommunications c ...
,
Wi-Fi,
WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options.
The WiMA ...
or other
wide area network (WAN) technology.
BTS is also referred to as the ''
node B'' (in
3G networks) or, simply, the ''
base station
Base station (or base radio station) is – according to the International Telecommunication Union's (ITU) Radio Regulations (RR) – a " land station in the land mobile service."
The term is used in the context of mobile telephony, wireless co ...
'' (BS). For discussion of the
LTE standard the abbreviation ''
eNB'' for evolved node B is widely used, and GNodeB for
5G.
Though the term BTS can be applicable to any of the wireless communication standards, it is generally associated with mobile communication technologies like
GSM
The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such as ...
and
CDMA
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication ...
. In this regard, a BTS forms part of the
base station subsystem
The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of s ...
(BSS) developments for system management. It may also have equipment for
encrypting
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...
and decrypting communications, spectrum filtering tools (band pass filters) and so on.
Antennas
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies a ...
may also be considered as components of BTS in general sense as they facilitate the functioning of BTS. Typically a BTS will have several transceivers (TRXs) which allow it to serve several different frequencies and different sectors of the cell (in the case of sectorised base stations). A BTS is controlled by a parent
base station controller
The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of s ...
via the base station control function (BCF). The BCF is implemented as a discrete unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance (O&M) connection to the
network management system (NMS), and manages operational states of each TRX, as well as software handling and alarm collection. The basic structure and functions of the BTS remains the same regardless of the wireless technologies.
General architecture
A BTS is usually composed of:
; Transceiver (TRX): Provides transmission and reception of signals. It also does sending and reception of signals to and from higher network entities (like the base station controller in mobile telephony).
; Power amplifier (PA): Amplifies the signal from TRX for transmission through antenna; may be integrated with TRX.
; Combiner: Combines feeds from several TRXs so that they could be sent out through a single antenna. Allows for a reduction in the number of antenna used.
; Multiplexer: For separating sending and receiving signals to/from antenna. Does sending and receiving signals through the same antenna ports (cables to antenna).
; Antenna: This is the structure that the BTS lies underneath; it can be installed as it is or disguised in some way (concealed
cellular sites).
; Alarm extension system: Collects working status alarms of various units in the BTS and extends them to operations and maintenance (O&M) monitoring stations.
; Control function: Controls and manages the various units of BTS, including any software. On-the-spot configurations, status changes, software upgrades, etc. are done through the control function.
; Baseband receiver unit (BBxx): Frequency hopping, signal DSP.
Terms regarding a mobile BTS
; Diversity techniques: To improve the quality of the received signal, often two receiving antennas are used, placed at a distance equal to an odd multiple of a quarter of the corresponding wavelength. For 900 MHz, this wavelength is 33 cm. This technique, known as antenna diversity or
space diversity
Antenna diversity, also known as space diversity or spatial diversity, is any one of several wireless diversity schemes that uses two or more antennas to improve the quality and reliability of a wireless link. Often, especially in urban and ind ...
, avoids interruption caused by path
fading. The antennas can be spaced horizontally or vertically. Horizontal spacing requires more complex installation, but brings better performance.
: Other than antenna or space diversity, there are other
diversity techniques such as frequency/time diversity, antenna pattern diversity, and polarization diversity.
: Splitting refers to the flow of power within a particular area of the cell, known as a sector. Every field can therefore be considered like one new cell.
Directional antennas reduce LoRa (long-range) interference. If not sectorised, the cell will be served by an
omnidirectional antenna, which radiates in all directions. A typical structure is the trisector, also known as clover, in which there are three sectors served by separate antennas. Each sector has a separate direction of tracking, typically of 120° with respect to the adjacent ones. Other orientations may be used to suit the local conditions. Bisectored cells are also implemented. These are most often oriented with the antennas serving sectors of 180° separation to one another, but again, local variations do exist.
Gallery
See also
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Mobile cell sites
Mobile cell sites are infrastructures transportable on trucks, allowing fast and easy installation in restricted spaces. Their use is strategic for the rapid expansion of cellular networks putting into service point-to-point radio connections as ...
*
OpenBTS
OpenBTS (Open Base Transceiver Station) is a software-based GSM access point, allowing standard GSM-compatible mobile phones to be used as SIP endpoints in Voice over IP (VoIP) networks. OpenBTS is open-source software developed and maintained by ...
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Cell ID
Further reading
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External links
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References
{{Reflist
Wireless networking