29-06-2012, 01:20 PM
2G technologies
[attachment=26094]
DAMPS
Standard name is IS-54
30 KHz channel spacing of AMPS and frequency bands (824-849 and 869-894 MHz) as AMPS
This system is most often referred to as TDMA
IS-136 added feature to IS-54 text messaging & circuit switched data.
IS-54 stands for Interim Standard-54 and specifies 84 control channels, 42 of which are shared with AMPS
The channel transmission bit rate for digitally modulating the carrier is 48.6 kbit/s. Each frame has six time slots of 6.67-ms duration.
IS-136
IS-136 eventually added an extra channel to the IS-54 hybrid design.
Unlike IS-54, IS-136 utilizes time division multiplexing for both voice and control channel transmissions
IS-136 added a number of features to the original IS-54 specification, including text messaging, circuit switched data (CSD), and an improved compression protocol.
IS-136 TDMA traffic channels use π/4-DQPSK modulation at a 24.3-kbaud channel rate and gives an effective 48.6 kbit/s data rate across the six time slots comprising one frame in the 30 kHz channel.
Base Station Subsystem (BSS)
It comprises two parts, the Base Station (BS) and the Base Station Controller (BSC).
These communicate across the standardized Abis interface
BSCs are quite intelligent and perform many of the necessary functions to enable the link between the BSs and the MSs.
[attachment=26094]
DAMPS
Standard name is IS-54
30 KHz channel spacing of AMPS and frequency bands (824-849 and 869-894 MHz) as AMPS
This system is most often referred to as TDMA
IS-136 added feature to IS-54 text messaging & circuit switched data.
IS-54 stands for Interim Standard-54 and specifies 84 control channels, 42 of which are shared with AMPS
The channel transmission bit rate for digitally modulating the carrier is 48.6 kbit/s. Each frame has six time slots of 6.67-ms duration.
IS-136
IS-136 eventually added an extra channel to the IS-54 hybrid design.
Unlike IS-54, IS-136 utilizes time division multiplexing for both voice and control channel transmissions
IS-136 added a number of features to the original IS-54 specification, including text messaging, circuit switched data (CSD), and an improved compression protocol.
IS-136 TDMA traffic channels use π/4-DQPSK modulation at a 24.3-kbaud channel rate and gives an effective 48.6 kbit/s data rate across the six time slots comprising one frame in the 30 kHz channel.
Base Station Subsystem (BSS)
It comprises two parts, the Base Station (BS) and the Base Station Controller (BSC).
These communicate across the standardized Abis interface
BSCs are quite intelligent and perform many of the necessary functions to enable the link between the BSs and the MSs.