06-04-2012, 10:31 AM
GSM Architecture
finalreoprt.docx (Size: 121.72 KB / Downloads: 35)
Introduction to training
GTL will persist to be customer-centric and gradually extend our integrated advantages in the Telecom Networks, Global Services and Devices areas based around customer requirements. Moving forward, we are committed to providing products and solutions for the Cloud, Pipe and Devices businesses and helping operators to achieve business success with our ABC strategy: growing average revenue per user (ARPU), increasing bandwidth and reducing cost.
Telecom Networks: All-IP Convergence, Application Support, Responsive and Cloud Computing
History of GSM
During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany. Each country developed its own system, which was incompatible with everyone else's in equipment and operation. This was an undesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there was also a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be realized.
The Europeans realized this early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Spécial Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria:
3. Services provided by GSM
From the beginning, the planners of GSM wanted ISDN compatibility in terms of the services offered and the control signalling used. However, radio transmission limitations, in terms of bandwidth and cost, do not allow the standard ISDN B-channel bit rate of 64 kbps to be practically achieved.
Using the ITU-T definitions, telecommunication services can be divided into bearer services, teleservices, and supplementary services. The most basic teleservice supported by GSM is telephony. As with all other communications, speech is digitally encoded and transmitted through the GSM network as a digital stream. There is also an emergency service, where the nearest emergency-service provider is notified by dialing three digits (similar to 911).
Architecture of the GSM network
The basic block diagram of GSM includes Mobile Station (MS), Base Station System (BSS), that includes Base Transceiver System (BTS) and Base Station Controller (BSC), and Switching Subsystem that includes Mobile Switching Centre (MSC) and Gateway MSC (GMSC).
A GSM network is composed of several functional entities, whose functions and interfaces are specified. The GSM network can be divided into three broad parts. The Mobile Station is carried by the subscriber. The Base Station Subsystem controls the radio link with the Mobile Station. The Network Subsystem, the main part of which is the Mobile services Switching Center (MSC), performs the switching of calls between the mobile users, and between mobile and fixed network users.
Packet Control Unit
The Packet Control Unit (PCU) is a late addition to the GSM standard. It performs some of the processing tasks of the BSC, but for packet data. The allocation of channels between voice and data is controlled by the base station, but once a channel is allocated to the PCU, the PCU takes full control over that channel.
The PCU can be built into the base station, built into the BSC or even, in some proposed architectures, it can be at the SGSN site.
BSS interfaces
Image of the GSM network, showing the BSS interfaces to the MS, NSS and GPRS Core Network
Um - The air interface between the MS (Mobile Station) and the BTS. This interface uses LAPDm protocol for signaling, to conduct call control, measurement
finalreoprt.docx (Size: 121.72 KB / Downloads: 35)
Introduction to training
GTL will persist to be customer-centric and gradually extend our integrated advantages in the Telecom Networks, Global Services and Devices areas based around customer requirements. Moving forward, we are committed to providing products and solutions for the Cloud, Pipe and Devices businesses and helping operators to achieve business success with our ABC strategy: growing average revenue per user (ARPU), increasing bandwidth and reducing cost.
Telecom Networks: All-IP Convergence, Application Support, Responsive and Cloud Computing
History of GSM
During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany. Each country developed its own system, which was incompatible with everyone else's in equipment and operation. This was an undesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there was also a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be realized.
The Europeans realized this early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Spécial Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria:
3. Services provided by GSM
From the beginning, the planners of GSM wanted ISDN compatibility in terms of the services offered and the control signalling used. However, radio transmission limitations, in terms of bandwidth and cost, do not allow the standard ISDN B-channel bit rate of 64 kbps to be practically achieved.
Using the ITU-T definitions, telecommunication services can be divided into bearer services, teleservices, and supplementary services. The most basic teleservice supported by GSM is telephony. As with all other communications, speech is digitally encoded and transmitted through the GSM network as a digital stream. There is also an emergency service, where the nearest emergency-service provider is notified by dialing three digits (similar to 911).
Architecture of the GSM network
The basic block diagram of GSM includes Mobile Station (MS), Base Station System (BSS), that includes Base Transceiver System (BTS) and Base Station Controller (BSC), and Switching Subsystem that includes Mobile Switching Centre (MSC) and Gateway MSC (GMSC).
A GSM network is composed of several functional entities, whose functions and interfaces are specified. The GSM network can be divided into three broad parts. The Mobile Station is carried by the subscriber. The Base Station Subsystem controls the radio link with the Mobile Station. The Network Subsystem, the main part of which is the Mobile services Switching Center (MSC), performs the switching of calls between the mobile users, and between mobile and fixed network users.
Packet Control Unit
The Packet Control Unit (PCU) is a late addition to the GSM standard. It performs some of the processing tasks of the BSC, but for packet data. The allocation of channels between voice and data is controlled by the base station, but once a channel is allocated to the PCU, the PCU takes full control over that channel.
The PCU can be built into the base station, built into the BSC or even, in some proposed architectures, it can be at the SGSN site.
BSS interfaces
Image of the GSM network, showing the BSS interfaces to the MS, NSS and GPRS Core Network
Um - The air interface between the MS (Mobile Station) and the BTS. This interface uses LAPDm protocol for signaling, to conduct call control, measurement