The abject transceiver station, or BTS, contains the accessories for transmitting and accepting radio signals (transceivers), antennas, and accessories for encrypting and decrypting communications with the abject abject ambassador (BSC). Typically a BTS for annihilation added than a picocell will accept several transceivers (TRXs) which acquiesce it to serve several altered frequencies and altered sectors of the corpuscle (in the case of sectorised abject stations).
A BTS is controlled by a ancestor BSC via the "base abject ascendancy function" (BCF). The BCF is implemented as a detached assemblage or even congenital in a TRX in bunched abject stations. The BCF provides an operations and aliment (O&M) affiliation to the arrangement administration arrangement (NMS), and manages operational states of anniversary TRX, as able-bodied as software administration and anxiety collection.
The functions of a BTS alter depending on the cellular technology acclimated and the cellular blast provider. There are vendors in which the BTS is a apparent transceiver which receives advice from the MS (mobile station) through the Um air interface and again converts it to a TDM (PCM) based interface, the Abis interface, and sends it appear the BSC. There are vendors which body their BTSs so the advice is preprocessed, ambition corpuscle lists are generated and even intracell handover (HO) can be absolutely handled. The advantage in this case is beneath amount on the big-ticket Abis interface.
The BTSs are able with radios that are able to attune band 1 of interface Um; for GSM 2G+ the accentuation blazon is GMSK, while for EDGE-enabled networks it is GMSK and 8-PSK.
Antenna combiners are implemented to use the aforementioned antenna for several TRXs (carriers), the added TRXs are accumulated the greater the combiner accident will be. Up to 8:1 combiners are begin in micro and pico beef only.
Frequency bent is generally acclimated to admission all-embracing BTS performance; this involves the accelerated switching of articulation cartage amid TRXs in a sector. A bent arrangement is followed by the TRXs and handsets application the sector. Several bent sequences are available, and the arrangement in use for a accurate corpuscle is always advertisement by that corpuscle so that it is accepted to the handsets.
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 accommodation as some advice is appropriate to be advertisement to handsets in the breadth that the BTS serves. This advice allows the handsets to analyze the arrangement and accretion admission to it. This signalling makes use of a approach accepted as the Advertisement Ascendancy Approach (BCCH).
edit Sectorisation
Further information: Breadth antenna
By application directional antennae on a abject station, anniversary pointing in altered directions, it is accessible to sectorise the abject abject so that several altered beef are served from the aforementioned location. Typically these directional antennas accept a beamwidth of 65 to 85 degrees. This increases the cartage accommodation of the abject abject (each abundance can backpack eight articulation channels) whilst not abundantly accretion the arrest acquired to adjoining beef (in any accustomed direction, alone a baby amount of frequencies are getting broadcast). Typically two antennas are acclimated per sector, at agreement of ten or added wavelengths apart. This allows the abettor to affected the furnishings of crumbling due to concrete phenomena such as multipath reception. Some addition of the accustomed arresting as it leaves the antenna is generally acclimated to bottle the antithesis amid uplink and downlink signal.
A BTS is controlled by a ancestor BSC via the "base abject ascendancy function" (BCF). The BCF is implemented as a detached assemblage or even congenital in a TRX in bunched abject stations. The BCF provides an operations and aliment (O&M) affiliation to the arrangement administration arrangement (NMS), and manages operational states of anniversary TRX, as able-bodied as software administration and anxiety collection.
The functions of a BTS alter depending on the cellular technology acclimated and the cellular blast provider. There are vendors in which the BTS is a apparent transceiver which receives advice from the MS (mobile station) through the Um air interface and again converts it to a TDM (PCM) based interface, the Abis interface, and sends it appear the BSC. There are vendors which body their BTSs so the advice is preprocessed, ambition corpuscle lists are generated and even intracell handover (HO) can be absolutely handled. The advantage in this case is beneath amount on the big-ticket Abis interface.
The BTSs are able with radios that are able to attune band 1 of interface Um; for GSM 2G+ the accentuation blazon is GMSK, while for EDGE-enabled networks it is GMSK and 8-PSK.
Antenna combiners are implemented to use the aforementioned antenna for several TRXs (carriers), the added TRXs are accumulated the greater the combiner accident will be. Up to 8:1 combiners are begin in micro and pico beef only.
Frequency bent is generally acclimated to admission all-embracing BTS performance; this involves the accelerated switching of articulation cartage amid TRXs in a sector. A bent arrangement is followed by the TRXs and handsets application the sector. Several bent sequences are available, and the arrangement in use for a accurate corpuscle is always advertisement by that corpuscle so that it is accepted to the handsets.
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 accommodation as some advice is appropriate to be advertisement to handsets in the breadth that the BTS serves. This advice allows the handsets to analyze the arrangement and accretion admission to it. This signalling makes use of a approach accepted as the Advertisement Ascendancy Approach (BCCH).
edit Sectorisation
Further information: Breadth antenna
By application directional antennae on a abject station, anniversary pointing in altered directions, it is accessible to sectorise the abject abject so that several altered beef are served from the aforementioned location. Typically these directional antennas accept a beamwidth of 65 to 85 degrees. This increases the cartage accommodation of the abject abject (each abundance can backpack eight articulation channels) whilst not abundantly accretion the arrest acquired to adjoining beef (in any accustomed direction, alone a baby amount of frequencies are getting broadcast). Typically two antennas are acclimated per sector, at agreement of ten or added wavelengths apart. This allows the abettor to affected the furnishings of crumbling due to concrete phenomena such as multipath reception. Some addition of the accustomed arresting as it leaves the antenna is generally acclimated to bottle the antithesis amid uplink and downlink signal.
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