"The overall slot structure for this channel is the same as that used within GSM, having the same power profile, and timing advance attributes to overcome the different signal travel times to the base station dependent upon the distance the mobile is from the base station. This enables the burst to fit in seamlessly with the existing GSM structure."

"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.
[...]
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."

"A base transceiver station (BTS) or cell site is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets)... [...] The network can be that of any of the wireless communication technologies like GSM, CDMA, WLL, WAN, WiFi, WiMAX etc.

BTS is also referred to as the radio base station (RBS), node B (in 3G Networks) or, simply, the base station (BS).
[...]
A GSM network is made up of three subsystems: [...]
- The Base Station subsystem (BSS) – comprising a BSC and several BTSes
[...]
In this regard, a BTS forms part of the base station subsystem (BSS) developments for system management.
[...]
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 via the base station control function (BCF).
[...]
Splitting: The flow of power within a particular area of the cell, known as sector. Every field can therefore be considered like one new cell. By using directional antennas, the co-channel interference is reduced. A typical structure is the trisector, also known as clover, in which there are three sectors, each one served by separate antennas. Every sector has a separate direction of tracking of 120° with respect to the adjacent ones. If not sectorised, the cell will be served by an omnidirectional antenna, which radiates in all directions. Bisectored cells are also implemented with the antennas serving sectors of 180° separation to one another."

"However on the GPRS,the LLC (between MS-SGSN) and RLC/MAC (between MS-
BSS) layer that make up the data link between the MS and the network. The protocol is
mainly an adapted version of the LAPDm protocol used in GSM.The LLC Protocol
establishes a logical link between MS and SGSN. Its functionality includes sequence
control, in-order delivery, flow control,detection of transmission errors, and
retransmission (automatic repeat request (ARQ)). The data confidentiality is ensured by
ciphering functions. It operates either in an unacknowledged mode, not taking care of
packet losses, or in an acknowledged mode, which applies retransmissions and flow
control to ensure a correct delivery of data.

The RLC/MAC layerat the air interface includes two functions. The main purpose of the
radio link control (RLC) layer is to establish a reliable link between the MS and the BSS.
RLC is always operated in an acknowledged mode with a sliding window flow control
mechanism and a selective ARQ mode providing a reliable link between MS and BSS.
This includes the segmentation and reassembly of LLC frames into RLC data blocks and
ARQ of uncorrectable codewords.

This new medium access control (MAC) scheme was changed to meet the demands of the packet oriented data transmission. The RLC/MAC layer ensures the concurrent
access to radio resources in a more flexible way compared to the unmodified TDMA
structure of GSM. It controls the access attempts of an MS on the radio channel shared
by several MSs. It employs algorithms for contention resolution, multiuser multiplexing
on a PDTCH, and scheduling and prioritizing based on the negotiated QoS. The
flexibility is achieved by the introduction of a logical Packet Data Traffic Channel
(PDTCH) which is multiplexed onto a physical data channel, the Packet Data Channel
(PDCH), which corresponds to one timeslot (TS) in the GSM TDMA frame. Up to eight of
these PDTCHs share one PDCH."

"Cell horizontal radius varies depending on antenna height, antenna gain and propagation conditions from a couple of hundred meters to several tens of kilometres. The longest distance the GSM specification supports in practical use is 35 kilometres (22 mi)."