 A typical GSM Base Station 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 speech channels, allocation of radio channels to mobile phones, paging, quality management of transmission and reception over the Air interface and many other tasks related to the radio network. Image File history File linksMetadata Size of this preview: 436 × 599 pixel Image in higher resolution (1454 × 1999 pixel, file size: 1. ...
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Network Switching Subsystem, or NSS, is the component of a GSM system that carries out switching functions and manages the communications between mobile phones and the Public Switched Telephone Network. ...
It has been suggested that this article or section be merged with pager. ...
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{stub} In mobile communication, the air interface is the radio-frequency portion of the circuit between the mobile station and the active base station. ...
Base Transceiver Station
 Base Transceiver Station Antenna in Paris The Base Transceiver Station, or BTS, contains the equipment for transmitting and receiving of radio signals (transceivers), antennas, and equipment for encrypting and decrypting communications with the Base Station Controller (BSC). Typically a BTS for anything other than a picocell 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 BSC 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. Image File history File linksMetadata Download high-resolution version (1536x2048, 1083 KB) En: A GSM base station on a roof of Paris, France Fr: Une antenne relais GSM sur un toit à Paris, France Copyright © 2006 ~Pyb Photo by myself. ...
Image File history File linksMetadata Download high-resolution version (1536x2048, 1083 KB) En: A GSM base station on a roof of Paris, France Fr: Une antenne relais GSM sur un toit à Paris, France Copyright © 2006 ~Pyb Photo by myself. ...
A typical BTS tower which holds the antenna. ...
In computer networking, the term transceiver (sometimes abbreviated to TCVR) is a device that performs, within one chassis, both transmitting and receiving functions that is in a common housing, sometimes designed for portable or mobile use, uses common circuit components for both transmitting and receiving which provides half-duplex operation. ...
In biology, antenna (plural: antennae) refers to the sensing organs of several arthropods. ...
Encrypt redirects here. ...
A Picocell is wireless communication system typically covering a small area, such as in-building (offices, shopping malls, train stations, etc. ...
For other uses, see Frequency (disambiguation). ...
The functions of a BTS vary depending on the cellular technology used and the cellular telephone provider. There are vendors in which the BTS is a plain transceiver which receives information from the MS (Mobile Station) through the Um (Air Interface) and then converts it to a TDM ("PCM") based interface, the Abis, and sends it towards the BSC. There are vendors which build their BTSs so the information is preprocessed, target cell lists are generated and even intracell handover (HO) can be fully handled. The advantage in this case is less load on the expensive Abis interface.
The BTSs are equipped with radios that are able to modulate layer 1 of interface Um; for GSM 2G+ the modulation type is GMSK, while for EDGE-enabled networks it is GMSK and 8-PSK.
Antenna combiners are implemented to use the same antenna for several TRXs (carriers), the more TRXs are combined the greater the combiner loss will be. Up to 8:1 combiners are found in micro and pico cells only.
Frequency hopping is often used to increase overall BTS performance; this involves the rapid switching of voice traffic between TRXs in a sector. A hopping sequence is followed by the TRXs and handsets using the sector. Several hopping sequences are available, and the sequence in use for a particular cell is continually broadcast by that cell so that it is known to the handsets. Frequency-hopping spread spectrum (FHSS) is a spread-spectrum method of transmitting signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. ...
A TRX transmits and receives according to the GSM standards, which specify eight TDMA timeslots per radio frequency. A TRX may lose some of this capacity as some information is required to be broadcast to handsets in the area that the BTS serves. This information allows the handsets to identify the network and gain access to it. This signalling makes use of a channel known as the BCCH (Broadcast Control Channel). Global System for Mobile communications (GSM: originally from Groupe Spécial Mobile) is the most popular standard for mobile phones in the world. ...
Time Division Multiple Access (TDMA) is a technology for shared medium (usually radio) networks. ...
Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. ...
Sectorisation By using directional antennas on a base station, each pointing in different directions, it is possible to sectorise the base station so that several different cells are served from the same location. Typically these directional antennas have a beamwidth of 65 to 85 degrees. This increases the traffic capacity of the base station (each frequency can carry eight voice channels) whilst not greatly increasing the interference caused to neighboring cells (in any given direction, only a small number of frequencies are being broadcast). Typically two antennas are used per sector, at spacing of ten or more wavelengths apart. This allows the operator to overcome the effects of fading due to physical phenomena such as multipath reception. Some amplification of the received signal as it leaves the antenna is often used to preserve the balance between uplink and downlink signal. Log-periodic dipole array A directional antenna is an antenna which transmits or receives maximum power in a particular direction. ...
For other uses, see Interference (disambiguation). ...
For other uses, see Wavelength (disambiguation). ...
Fading (or fading channels) are mathematical models for the distortion that a carrier-modulated telecommunication signal experiences over certain propagation media. ...
Generally, amplification is a basic process sometimes seen in nature, and often used in processes which involve a signal which must be made stronger. ...
Base Station Controller The Base Station Controller (BSC) provides, classically, the intelligence behind the BTSs. Typically a BSC has 10s or even 100s of BTSs under its control. The BSC handles allocation of radio channels, receives measurements from the mobile phones, controls handovers from BTS to BTS (except in the case of an inter-BSC handover in which case control is in part the responsibility of the Anchor MSC). A key function of the BSC is to act as a concentrator where many different low capacity connections to BTSs (with relatively low utilisation) become reduced to a smaller number of connections towards the Mobile Switching Center (MSC) (with a high level of utilisation). Overall, this means that networks are often structured to have many BSCs distributed into regions near their BTSs which are then connected to large centralised MSC sites. The Base Station Subsystem (BSS) is the section of a GSM network which is responsible for transmitting to and receiving radio signals from the mobile phone. ...
The GSM Core network is the heart of a GSM system, the most common mobile phone system in the world. ...
In telecommunication, the term concentrator has the following meanings: In data transmission, a functional unit that permits a common path to handle more data sources than there are channels currently available within the path. ...
Network Switching Subsystem, or NSS, is the component of a GSM system that carries out switching functions and manages the communications between mobile phones and the Public Switched Telephone Network. ...
The BSC is undoubtedly the most robust element in the BSS as it is not only a BTS controller but, for some vendors, a full switching center, as well as an SS7 node with connections to the MSC and SGSN (when using GPRS). It also provides all the required data to the Operation Support Subsystem (OSS) as well as to the performance measuring centers. The GPRS system is used by GSM Mobile phones, as of 2004 the most common mobile phone system in the world, for transmitting IP packets. ...
General Packet Radio Service (GPRS) is a Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones. ...
A BSC is often based on a distributed computing architecture, with redundancy applied to critical functional units to ensure availability in the event of fault conditions. Redundancy often extends beyond the BSC equipment itself and is commonly used in the power supplies and in the transmission equipment providing the A-ter interface to PCU.
The databases for all the sites, including information such as carrier frequencies, frequency hopping lists, power reduction levels, receiving levels for cell border calculation, are stored in the BSC. This data is obtained directly from radio planning engineering which involves modelling of the signal propagation as well as traffic projections. Carrier frequency is the fundamental frequency used in both amplitude modulation and frequency modulation i. ...
Transcoder Although the Transcoding (compressing/decompressing) function is as standard defined as a BSC function, there are several vendors which have implemented the solution in a stand-alone rack using a proprietary interface. This subsystem is also referred to as the TRAU (Transcoder and Rate Adaptation Unit). The transcoding function converts the voice channel coding between the GSM (Regular Pulse Excited-Long Term Prediction, also known as RPE-LPC) coder and the CCITT standard PCM (G.711 A-law or u-law). Since the PCM coding is 64 kbit/s and the GSM coding is 13 kbit/s, this also involves a buffering function so that PCM 8-bit words can be recoded to construct GSM 20 ms traffic blocks, to compress voice channels from the 64 kbit/s PCM standard to the 13 kbit/s rate used on the air interface. Some networks use 32 kbit/s ADPCM on the terrestrial side of the network instead of 64 kbit/s PCM and the TRAU converts accordingly. When the traffic is not voice but data such as fax or email, the TRAU enables its Rate Adaptation Unit function to give compatibility between the BSS data rates and the MSC capability. Image File history File linksMetadata Download high resolution version (2045x1363, 573 KB) Summary Two GSM base stations disguised as trees in Dublin, Ireland. ...
Image File history File linksMetadata Download high resolution version (2045x1363, 573 KB) Summary Two GSM base stations disguised as trees in Dublin, Ireland. ...
It has been suggested that this article or section be merged with Tree (disambiguation). ...
For other uses, see Dublin (disambiguation). ...
In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ...
However, at least in Siemens' and Nokia's architecture, the Transcoder is an identifiable separate sub-system which will normally be co-located with the MSC. In some of Ericsson's systems it is integrated to the MSC rather than the BSC. The reason for these designs is that if the compression of voice channels is done at the site of the MSC, fixed transmission link costs can be reduced. Siemens has the following uses: Siemens is a German family name carried by generations of the telecommunications industrialists, including Werner von Siemens, Sir William Siemens, Wilhelm von Siemens and Peter von Siemens Siemens AG is a German electrical and telecommunications company, founded as a telegraph equipment manufacturer by Werner von...
This article is about the telecommunications corporation. ...
Ericsson () NASDAQ: ERIC. Founded in 1876, Ericsson is a leading provider of communications networks, related services and handset technology platforms. ...
Packet Control Unit The Packet Control Unit (PCU) is a late addition to the GSM standard. It performs some of the processing tasks of the BSC, but for packet data. The allocation of channels between voice and data is controlled by the base station, but once a channel is allocated to the PCU, the PCU takes full control over that channel.
The PCU can be built into the base station, built into the BSC or even, in some proposed architectures, it can be at the SGSN site.
BSS interfaces
 Image of the GSM network, showing the BSS interfaces to the MS, NSS and GPRS Core Network - Um – The air interface between the MS (Mobile Station) and the BTS. This interface uses LAPDm protocol for signaling, to conduct call control, measurement reporting, Handover, Power control, Authentication, Authorization, Location Update and so on. Traffic and Signaling are sent in bursts of 0.577 ms at intervals of 4.615 ms, to form data blocks each 20 ms.
- Abis – The interface between the Base Transceiver Station and Base Station Controller. Generally carried by a DS-1, ES-1, or E1 TDM circuit. Uses TDM subchannels for traffic (TCH), LAPD protocol for BTS supervision and telecom signaling, and carries synchronization from the BSC to the BTS and MS.
- A – The interface between the BSC and Mobile Switching Center. It is used for carrying Traffic channels and the BSSAP user part of the SS7 stack. Although there are usually transcoding units between BSC and MSC, the signaling communication takes place between these two ending points and the transcoder unit doesn't touch the SS7 information, only the voice or CS data are transcoded or rate adapted.
- Ater – The interface between the Base Station Controller and Transcoder. It is a proprietary interface whose name depends on the vendor (for example Ater by Nokia), it carries the A interface information from the BSC leaving it untouched.
- Gb – Connects the BSS to the Serving GPRS Support Node (SGSN) in the GPRS Core Network.
Image File history File links Size of this preview: 800 × 522 pixelsFull resolution (808 × 527 pixel, file size: 56 KB, MIME type: image/png) This diagram shows the simplified structure of a GSM network. ...
Image File history File links Size of this preview: 800 × 522 pixelsFull resolution (808 × 527 pixel, file size: 56 KB, MIME type: image/png) This diagram shows the simplified structure of a GSM network. ...
The Mobile Station(MS) comprises all user equipment and software needed for communication with a GSM network. ...
The Base Station Subsystem (BSS) is the section of a GSM network which is responsible for handling traffic and signaling between a mobile phone and the Network Switching Subsystem. ...
In telecommunication, the term handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another. ...
(Electric) Power Control deals with routing electric power, controlling its quality, and controlling the devices attached to a power line. ...
For other uses of the terms authentication, authentic and authenticity, see authenticity. ...
In security engineering and computer security, authorization, is a part of the operating system that protects computer resources by only allowing those resources to be used by resource consumers that have been granted authority to use them. ...
Link Access Procedures on the D channel (LAPD), specified in ITU-T Q.920 and ITU-T Q.921, is the second layer protocol on the ISDN protocol stack in the D channel. ...
The GPRS system is used by GSM Mobile phones, the most common mobile phone system in the world (as of 2004), for transmitting IP packets. ...
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