(Global System for Mobile Communications
GSM
Architecture of the GSM System
GSM-elements & interfaces
System Architecture: Radio Subsystem
Mobile Station (MS)
Mobile Station (MS)
Block Diagram of BTS with TRX
Block Diagram of BTS Contd.
• Transmitter/Receiver Module – The TRX consists of a low-frequency part for digital signal processing and a high-frequency part for GMSK modulation and demodulation. • The operations and maintenance (O&M) module – connected directly to the BSC by means of a specifically assigned O&M channel. – That allows the O&M module to process the commands from the BSC or the MSC directly into the BTS and to report the results – O&M module provides a human-machine interface (HMI), which allows for local control of the BTS.
BTS & BSC
Block Diagram of BSC
BSC Contd….
• Terminal Control Elements (TCEs)
– Abis-Interface Terminal Control Elements
• Abis-TCEs are to set up LAPD connections toward the BTS peers, the transfer of signaling data, and last—but not least—the transparent transfer of payload.
– A-Interface Terminal Control Elements
• The connection of a BSC to the MSC is established via the A-TCEs. • A-TCEs is setting up and operating the SS7/SCCP connection toward the MSC.
BSC Contd….
• Database (DB)
– maintenance status of the whole BSS, the quality of the radio resources and terrestrial resources, and so on are dynamically administrated – BSC database contains the complete BTS operations software for all attached BTSs and all BSS specific information,such as assigned frequencies.
BSC Contd….
• Central Module
– One of the major tasks of the BSC is to decide when a handover should take place. The BSC may decide on intra-BTS handover and intraBSC handover without needing the MSC. In contrast, for all BSC external handovers, the BSC needs to involve the MSC. – Handover decision and power control are main tasks of the central module.
Transcoding Rate and Adaptation Unit (TRAU)
• The task of the TRAU is to compress or
Architecture of the GSM System
GSM-elements & interfaces
System Architecture: Radio Subsystem
Mobile Station (MS)
Mobile Station (MS)
Block Diagram of BTS with TRX
Block Diagram of BTS Contd.
• Transmitter/Receiver Module – The TRX consists of a low-frequency part for digital signal processing and a high-frequency part for GMSK modulation and demodulation. • The operations and maintenance (O&M) module – connected directly to the BSC by means of a specifically assigned O&M channel. – That allows the O&M module to process the commands from the BSC or the MSC directly into the BTS and to report the results – O&M module provides a human-machine interface (HMI), which allows for local control of the BTS.
BTS & BSC
Block Diagram of BSC
BSC Contd….
• Terminal Control Elements (TCEs)
– Abis-Interface Terminal Control Elements
• Abis-TCEs are to set up LAPD connections toward the BTS peers, the transfer of signaling data, and last—but not least—the transparent transfer of payload.
– A-Interface Terminal Control Elements
• The connection of a BSC to the MSC is established via the A-TCEs. • A-TCEs is setting up and operating the SS7/SCCP connection toward the MSC.
BSC Contd….
• Database (DB)
– maintenance status of the whole BSS, the quality of the radio resources and terrestrial resources, and so on are dynamically administrated – BSC database contains the complete BTS operations software for all attached BTSs and all BSS specific information,such as assigned frequencies.
BSC Contd….
• Central Module
– One of the major tasks of the BSC is to decide when a handover should take place. The BSC may decide on intra-BTS handover and intraBSC handover without needing the MSC. In contrast, for all BSC external handovers, the BSC needs to involve the MSC. – Handover decision and power control are main tasks of the central module.
Transcoding Rate and Adaptation Unit (TRAU)
• The task of the TRAU is to compress or