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Terminal Equipment
(TE)
The TE is the computer terminal that the end user uses. This
is the component used for the GPRS system to transmit and receive
end user packet data. For example, the TE could be a laptop computer.
The GPRS system provides for IP connectivity between the TE and
an Internet Service Provider (ISP), or a Corporate Local Area
Network (LAN) connected to the GPRS system. From the users point
of view the MT could be compared to a conventional modem. |
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Mobile Terminal
(MT)
The MT communicates with a TE, and over the air with the BTS,
the MT must be equipped with software for GPRS functionality
when used in conjunction with the GPRS system. The MT is associated
with a subscriber in the GSM system, the MT established SGSN.
Channel reselection is provided at the radio link between the
MT and the SGSN, the IP connection is static from the TE point
of view, that is, the TE does not know it is mobile and retains
its assigned IP address until the MT detached. |
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Base Station
System (BSS)
The BSS consists of a Base Station Controller (BSC) and a Base
Transceiver Station (BTS). The BTS is the radio equipment, that
transmits and receives information over the air to let the BSC
communicate with MSs in the BSCs service area. A group of BTSs
is controlled by the BSC, however for GPRS to work on the BTS
it must have the GPRS specific software.
The BSC provides all the radio
related functions. The BSC can set up, supervise and disconnect
circuit switched and packet switched calls, it has a high capacity
switch, this provides function such as handover decisions, cell
configuration data and channel assignment. The BSC must also
be equipped with both the GPRS hardware and software when used
for GPRS, one or several BSCs are served by an MSC, and a number
of BSCs are served by an SGSN.
The BTS separates the MS originated circuit switched calls from
the packet switched data communications, before the BSC forwards
a circuit switched calls to the MSC/VLR, and packet switched
data to the SGSN.
The standard GSM protocols are used with the BSC to achieve the
desired compatibility. |
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Mobile Services
Switching Center (MSC)
The MSC performs the telephony switching functions of the GSM
circuit switched system, like the SGSN switches the GSM packet
switched traffic, it controls calls to and from other telephony
and data systems, such as the PSTN, ISDN, PLMN, Public Data Networks
and possibility some private networks. |