The document discusses various topics related to GSM including:
- The GSM system architecture is divided into the mobile station, base station subsystem, and network subsystem. The base station subsystem consists of base transceiver stations and base station controllers. The network subsystem includes mobile switching centers, home location registers, visitor location registers, and authentication centers.
- Interfaces include the Um air interface, Abis interface between the BTS and BSC, and A interface between the BSS and MSC. Various protocols are used on each interface including those for physical transmission, data link layer, and network layer.
- The GSM air interface Um uses TDMA/FDMA, dividing the radio frequency spectrum into frames divided into
This document provides an overview of the Global System for Mobile Communications (GSM) standard. It describes the key components of the GSM system architecture, including the mobile station, base station subsystem (consisting of base transceiver stations and base station controllers), and network subsystem (consisting of mobile switching centers, home location registers, visitor location registers, and authentication centers). It also outlines the various interfaces that connect these components, such as the air interface Um, Abis interface, and A interface, as well as the protocols used on each interface.
This document describes a wireless electronic notice board system that uses GSM technology to display text messages on an LCD screen. The system includes a microcontroller (Arduino), GSM module, and LCD. It works by receiving SMS messages via the GSM module and displaying them on the LCD. The system has applications in schools, offices, transportation hubs and for advertisements. It allows messages to be sent and displayed from a distance but has limitations such as needing a network connection and no password protection for sending messages.
The GSM network is comprised of the following components:
Network Elements
The GSM network incorporates a number of network elements to support mobile equipment. They are listed and described in the GSM network elements section of this chapter.
GSM subsystems
In addition, the network includes subsystems that are not formally recognized as network elements but are necessary for network operation. These are described in the GSM subsystems (non-network elements) section of this chapter.
Standardized Interfaces
GSM specifies standards for interfaces between network elements, which ensure the connectivity of GSM equipment from different manufacturers. These are listed in the Standardized interfaces section of this chapter.
Network Protocols
For most of the network communications on these interfaces, internationally recognized communications protocols have been used
These are identified in the Network protocols section of this chapter.
GSM Frequencies
The frequency allocations for GSM 900, Extended GSM and Digital Communications Systems are identified in the GSM frequencies section of this chapter.
GSM networks are digital and can cater for high system capacities. They are consistent with the world wide digitization of the telephone network, and are an extension of the Integrated Services Digital Network (ISDN), using a digital radio interface between the cellular network and the mobile subscriber equipment
The GSM system provides a greater subscriber capacity than analogue systems. GSM allows 25 kHz. Per user, that is, eight conversations per 200kHz. Channel pair (a pair comprising one transmit channel and one receive channel). Digital channel coding and the modulation used makes the signal resistant to interference from the cells where the same frequencies are re-used (co-channel interference); a Carrier to Interference Ratio (C/I) level of 9 dB is achieved, as opposed to the 18 dB typical with analogue cellular. This allows increased geographic reuse by permitting a reduction in the number of cells in the reuse pattern. Since this number is directly controlled by the amount of interference, the radio transmission design can deliver acceptable performance.
Wireless electronic notice board using gsm technolgydhanshri_deshmukh
This document discusses the design of a wireless electronic notice board using GSM technology. It begins with introductions to GSM and embedded systems. It then shows the block diagram of the notice board, which includes a GSM modem connected to a microcontroller that controls an LCD display. The document discusses the history and services of GSM networks. It provides details on the architecture of GSM networks and their components like the mobile station, base station subsystem, and network subsystem.
This document proposes a public transportation information system that uses SMS (Short Message Service) to allow users to query bus schedules and routes without making phone calls. It describes a system that stores transportation data on a USB drive connected to an ARM microcontroller. The microcontroller is connected to a GSM module to allow it to send and receive SMS messages containing queries and responses about bus schedules and stops. The system aims to provide transportation information to users 24/7 through SMS to eliminate the need to wait for an operator to answer phone calls.
The document describes a GSM-based campus display system that allows information to be displayed continuously or at regular intervals on college/university campuses. It consists of a GSM receiver and display toolkit that can be programmed from an authorized mobile phone by sending SMS messages. The system receives and validates SMS messages and displays the information. It uses an AT89S52 microcontroller, HD44780 LCD for displaying text, and a Matrix Simado GDT11 GSM modem connected via RS232 serial interface to allow wireless control and updating of displays.
This document describes a wireless electronic notice board that displays notices sent via SMS from a mobile phone. The circuit uses an Arduino microcontroller, GSM module to receive SMS messages, and a 16x2 LCD for display. When an SMS with a notice message is sent, the GSM module receives it and sends it to the Arduino. The Arduino then extracts and displays the notice message on the LCD. This allows notices to be updated and viewed remotely via SMS from any location with cellular network access.
The document provides a software requirements specification for a GSM based e-notice board system. The system allows messages to be displayed on an LCD notice board by sending SMS texts from an authorized mobile phone to a GSM receiver module. It details the required system functionality, hardware and software requirements, theoretical foundation, system specifications including models and diagrams, task analysis and schedule. The system is designed to replace manual notice boards and allow remote updating of messages in an instantaneous manner through SMS.
This document provides an overview of the Global System for Mobile Communications (GSM) standard. It describes the key components of the GSM system architecture, including the mobile station, base station subsystem (consisting of base transceiver stations and base station controllers), and network subsystem (consisting of mobile switching centers, home location registers, visitor location registers, and authentication centers). It also outlines the various interfaces that connect these components, such as the air interface Um, Abis interface, and A interface, as well as the protocols used on each interface.
This document describes a wireless electronic notice board system that uses GSM technology to display text messages on an LCD screen. The system includes a microcontroller (Arduino), GSM module, and LCD. It works by receiving SMS messages via the GSM module and displaying them on the LCD. The system has applications in schools, offices, transportation hubs and for advertisements. It allows messages to be sent and displayed from a distance but has limitations such as needing a network connection and no password protection for sending messages.
The GSM network is comprised of the following components:
Network Elements
The GSM network incorporates a number of network elements to support mobile equipment. They are listed and described in the GSM network elements section of this chapter.
GSM subsystems
In addition, the network includes subsystems that are not formally recognized as network elements but are necessary for network operation. These are described in the GSM subsystems (non-network elements) section of this chapter.
Standardized Interfaces
GSM specifies standards for interfaces between network elements, which ensure the connectivity of GSM equipment from different manufacturers. These are listed in the Standardized interfaces section of this chapter.
Network Protocols
For most of the network communications on these interfaces, internationally recognized communications protocols have been used
These are identified in the Network protocols section of this chapter.
GSM Frequencies
The frequency allocations for GSM 900, Extended GSM and Digital Communications Systems are identified in the GSM frequencies section of this chapter.
GSM networks are digital and can cater for high system capacities. They are consistent with the world wide digitization of the telephone network, and are an extension of the Integrated Services Digital Network (ISDN), using a digital radio interface between the cellular network and the mobile subscriber equipment
The GSM system provides a greater subscriber capacity than analogue systems. GSM allows 25 kHz. Per user, that is, eight conversations per 200kHz. Channel pair (a pair comprising one transmit channel and one receive channel). Digital channel coding and the modulation used makes the signal resistant to interference from the cells where the same frequencies are re-used (co-channel interference); a Carrier to Interference Ratio (C/I) level of 9 dB is achieved, as opposed to the 18 dB typical with analogue cellular. This allows increased geographic reuse by permitting a reduction in the number of cells in the reuse pattern. Since this number is directly controlled by the amount of interference, the radio transmission design can deliver acceptable performance.
Wireless electronic notice board using gsm technolgydhanshri_deshmukh
This document discusses the design of a wireless electronic notice board using GSM technology. It begins with introductions to GSM and embedded systems. It then shows the block diagram of the notice board, which includes a GSM modem connected to a microcontroller that controls an LCD display. The document discusses the history and services of GSM networks. It provides details on the architecture of GSM networks and their components like the mobile station, base station subsystem, and network subsystem.
This document proposes a public transportation information system that uses SMS (Short Message Service) to allow users to query bus schedules and routes without making phone calls. It describes a system that stores transportation data on a USB drive connected to an ARM microcontroller. The microcontroller is connected to a GSM module to allow it to send and receive SMS messages containing queries and responses about bus schedules and stops. The system aims to provide transportation information to users 24/7 through SMS to eliminate the need to wait for an operator to answer phone calls.
The document describes a GSM-based campus display system that allows information to be displayed continuously or at regular intervals on college/university campuses. It consists of a GSM receiver and display toolkit that can be programmed from an authorized mobile phone by sending SMS messages. The system receives and validates SMS messages and displays the information. It uses an AT89S52 microcontroller, HD44780 LCD for displaying text, and a Matrix Simado GDT11 GSM modem connected via RS232 serial interface to allow wireless control and updating of displays.
This document describes a wireless electronic notice board that displays notices sent via SMS from a mobile phone. The circuit uses an Arduino microcontroller, GSM module to receive SMS messages, and a 16x2 LCD for display. When an SMS with a notice message is sent, the GSM module receives it and sends it to the Arduino. The Arduino then extracts and displays the notice message on the LCD. This allows notices to be updated and viewed remotely via SMS from any location with cellular network access.
The document provides a software requirements specification for a GSM based e-notice board system. The system allows messages to be displayed on an LCD notice board by sending SMS texts from an authorized mobile phone to a GSM receiver module. It details the required system functionality, hardware and software requirements, theoretical foundation, system specifications including models and diagrams, task analysis and schedule. The system is designed to replace manual notice boards and allow remote updating of messages in an instantaneous manner through SMS.
This document describes a scrolling message display board project that receives messages sent via SMS or GPRS and displays them on a liquid crystal display. It uses a GSM modem and microcontroller to wirelessly communicate with mobile phones and receive messages. The messages are then verified and displayed one at a time on the board. Potential applications include information boards, advertisements, education and more. It allows for wireless information sharing and notice posting in public spaces.
Topics covered in this presentation:
Abbreviations
Types of Cards
SIM Card Memory Architecture
RUM-Classifications
NV Vs RUIM
PRL
USIM
UICC Vs ICC
The document describes the key components and features of a mobile station. It discusses the mobile equipment (ME) which contains the radio components and allows network access. It also describes the subscriber identity module (SIM) card which provides subscriber information to allow chargeable calls and personalize the ME. It outlines the basic, supplementary and additional features a mobile station may have such as calling number display, keypad functions and short message capabilities.
The global system for mobile communications (GSM) is a set of recommendations and specifications for a digital cellular telephone network (known as a Public Land Mobile Network, or PLMN). These recommendations ensure the compatibility of equipment from different GSM manufacturers, and interconnectivity between different administrations, including operations across international boundaries
The GSM network is comprised of the following components:
Network Elements
The GSM network incorporates a number of network elements to support mobile equipment. They are listed and described in the GSM network elements section of this chapter.
GSM subsystems
In addition, the network includes subsystems that are not formally recognized as network elements but are necessary for network operation. These are described in the GSM subsystems (non-network elements) section of this chapter.
Standardized Interfaces
GSM specifies standards for interfaces between network elements, which ensure the connectivity of GSM equipment from different manufacturers. These are listed in the Standardized interfaces section of this chapter.
Network Protocols
For most of the network communications on these interfaces, internationally recognized communications protocols have been used
These are identified in the Network protocols section of this chapter.
GSM Frequencies
The frequency allocations for GSM 900, Extended GSM and Digital Communications Systems are identified in the GSM frequencies section of this chapter.
The document provides an introduction to the Global System for Mobile Communications (GSM). It describes that GSM is a set of recommendations and specifications for a digital cellular telephone network that ensures compatibility between equipment from different manufacturers. It divides the service area into regions called cells, with each cell having equipment to transmit and receive calls within its radio coverage area. The document then discusses various components of the GSM network including the mobile station, SIM card, base station subsystem, mobile switching center, home location register, visitor location register, and authentication center. It also covers frequency bands, handovers, and security features of GSM.
Flip-flops are basic storage elements in electronics that have two stable states. They are used to store state information and can change state by control signals. A finite-state machine (FSM) is a model used in computer programs and digital circuits to be in one of a finite number of states, changing states based on triggering events. A totem pole output is a circuit structure used with integrated circuits that uses one transistor to drive the output high and another to pull it low.
The system allows notices to be displayed on three LCD screens by sending an SMS to the GSM modem, which is connected to an microcontroller. The microcontroller then displays the SMS text on the LCD screens. It aims to provide a paperless solution for displaying notices in places like colleges, institutes, offices, etc. The document outlines the system's block diagram, components, power supply, microcontroller section, and applications. It concludes that the SMS-based electronic notice board overcomes issues with traditional paper-based boards.
project synopsis of the GSM based e-notice board for final year engineering project for computer science, electronics and communication, electrical and electronics students.
Multiuser sms based microcontroller wireless electronic boardKalees Pandiyan
This document describes a wireless SMS-based microcontroller system for displaying electronic notices. The system uses an AT89C52 microcontroller interfaced with a GSM modem via a MAX232 level converter. The microcontroller is programmed using Embedded C and interfaces with a PC using Visual Basic. Messages entered on the PC are sent via GSM and displayed on a 16x2 LCD screen. The system provides a wireless solution to remotely update notices with low errors and maintenance.
This document describes a GSM-based anti-theft system for vehicles. The system uses a microcontroller and GSM modem to send SMS alerts to the vehicle owner's phone if the vehicle alarm is triggered. This provides immediate notification even if the thief gets away with the car, allowing the owner to quickly contact authorities. The system components include a microcontroller, GSM modem, and power supply to integrate wireless features and allow the modem to send SMS messages by serially transferring AT commands.
The main aim of this project is to design an SMS driven automatic display notice board which can replace the currently used programmable electronic display. The message to be displayed is sent through a SMS from an authorized sender. The GSM receives the SMS, verifies the sender’s mobile identification pin(MIP) and displays the desired information on LCD.
This document describes an SMS-based notice board display system that uses a GSM modem to receive messages and display them on an LCD screen. An 8051 microcontroller is interfaced with a GSM modem and LCD display to fetch messages from the modem and display them. When a user sends an SMS message to the SIM card in the GSM modem, the microcontroller receives the message through AT commands and displays it on the attached 16x2 LCD screen. Block diagrams, component descriptions, and the circuit diagram are provided to explain the system design and functionality.
This document describes a mini project on an electronic notice board using GSM technology. The notice board receives SMS messages from mobile phones and displays them. Key aspects include:
1. A GSM modem receives SMS messages and transfers them to a microcontroller via serial communication.
2. The microcontroller verifies the password in the SMS and displays the message on an LCD screen.
3. The system could be used by banks, schools, and for advertising to instantly share information via SMS.
The document provides an overview of GSM systems, including:
- A review of first and second generation cellular networks and their focus on coverage over capacity.
- An overview of the key components of GSM architecture, including the mobile station, base station subsystem, and network switching system.
- Descriptions of the coverage and capacity challenges faced by early cellular networks as the subscriber base grew.
Iaetsd wireless electronic notice board using gsmIaetsd Iaetsd
This document describes a wireless electronic notice board system that uses GSM technology to display messages. An authorized user can send an SMS text message from their mobile phone to have it displayed on the electronic board. The system includes a GSM modem connected to a microcontroller which extracts the message and sends it to an LED display board. This allows messages to be shared quickly and remotely without physically updating a notice board. It could be used for applications like education, transportation, advertising and more.
Gsm based campus display system project reportKashyap Shah
Here are the key steps in the information transfer process for this GSM-based campus display system:
1. An authorized user sends an SMS from their mobile phone to the GSM modem connected to the system.
2. The GSM modem receives the SMS via the cellular network.
3. The microcontroller connected to the GSM modem reads the incoming SMS.
4. The microcontroller validates the sender's mobile number to check if they are authorized.
5. If authorized, the microcontroller extracts the message content from the SMS.
6. The microcontroller then encodes/converts the message into a format suitable for display on the LCD.
7. The microcontroller interfaces with
GSM(Global system for mobile communication ) is a second generation cellular standard developed to cater voice services and data delivery using digital modulation.
China had the most cellular subscribers in 2005 with 398 million, representing 19.3% of the global total. The top 15 countries accounted for 68.5% of the world's 2.065 billion cellular subscribers. GSM is now used by over a billion people in more than 200 countries, making it the dominant mobile technology globally. [/SUMMARY]
The document provides an overview of GSM, GPRS, and UMTS mobile wireless technologies. It describes that GSM is a digital cellular standard developed in Europe to provide wireless voice communications. GPRS and UMTS are extensions of GSM that add wireless data capabilities, with UMTS moving networks toward being fully IP-based and supporting broadband services. The key components of a GSM network are the mobile station (phone), base transceiver station (handles radio link), base station controller (manages radio network), and switching centers.
Pat Sims on Community broadband networksAnn Treacy
The document discusses emerging technologies that will impact fiber networks, including next generation architectures, new bandwidth requirements, and video and IP applications. It also summarizes the evolution of fiber networks from early uses connecting central offices to current implementations including passive optical networks, mobile backhaul, and cloud computing. Proper fiber techniques will allow networks built today to transition smoothly to future generations of access electronics and technologies over the next 50 years.
This document describes a scrolling message display board project that receives messages sent via SMS or GPRS and displays them on a liquid crystal display. It uses a GSM modem and microcontroller to wirelessly communicate with mobile phones and receive messages. The messages are then verified and displayed one at a time on the board. Potential applications include information boards, advertisements, education and more. It allows for wireless information sharing and notice posting in public spaces.
Topics covered in this presentation:
Abbreviations
Types of Cards
SIM Card Memory Architecture
RUM-Classifications
NV Vs RUIM
PRL
USIM
UICC Vs ICC
The document describes the key components and features of a mobile station. It discusses the mobile equipment (ME) which contains the radio components and allows network access. It also describes the subscriber identity module (SIM) card which provides subscriber information to allow chargeable calls and personalize the ME. It outlines the basic, supplementary and additional features a mobile station may have such as calling number display, keypad functions and short message capabilities.
The global system for mobile communications (GSM) is a set of recommendations and specifications for a digital cellular telephone network (known as a Public Land Mobile Network, or PLMN). These recommendations ensure the compatibility of equipment from different GSM manufacturers, and interconnectivity between different administrations, including operations across international boundaries
The GSM network is comprised of the following components:
Network Elements
The GSM network incorporates a number of network elements to support mobile equipment. They are listed and described in the GSM network elements section of this chapter.
GSM subsystems
In addition, the network includes subsystems that are not formally recognized as network elements but are necessary for network operation. These are described in the GSM subsystems (non-network elements) section of this chapter.
Standardized Interfaces
GSM specifies standards for interfaces between network elements, which ensure the connectivity of GSM equipment from different manufacturers. These are listed in the Standardized interfaces section of this chapter.
Network Protocols
For most of the network communications on these interfaces, internationally recognized communications protocols have been used
These are identified in the Network protocols section of this chapter.
GSM Frequencies
The frequency allocations for GSM 900, Extended GSM and Digital Communications Systems are identified in the GSM frequencies section of this chapter.
The document provides an introduction to the Global System for Mobile Communications (GSM). It describes that GSM is a set of recommendations and specifications for a digital cellular telephone network that ensures compatibility between equipment from different manufacturers. It divides the service area into regions called cells, with each cell having equipment to transmit and receive calls within its radio coverage area. The document then discusses various components of the GSM network including the mobile station, SIM card, base station subsystem, mobile switching center, home location register, visitor location register, and authentication center. It also covers frequency bands, handovers, and security features of GSM.
Flip-flops are basic storage elements in electronics that have two stable states. They are used to store state information and can change state by control signals. A finite-state machine (FSM) is a model used in computer programs and digital circuits to be in one of a finite number of states, changing states based on triggering events. A totem pole output is a circuit structure used with integrated circuits that uses one transistor to drive the output high and another to pull it low.
The system allows notices to be displayed on three LCD screens by sending an SMS to the GSM modem, which is connected to an microcontroller. The microcontroller then displays the SMS text on the LCD screens. It aims to provide a paperless solution for displaying notices in places like colleges, institutes, offices, etc. The document outlines the system's block diagram, components, power supply, microcontroller section, and applications. It concludes that the SMS-based electronic notice board overcomes issues with traditional paper-based boards.
project synopsis of the GSM based e-notice board for final year engineering project for computer science, electronics and communication, electrical and electronics students.
Multiuser sms based microcontroller wireless electronic boardKalees Pandiyan
This document describes a wireless SMS-based microcontroller system for displaying electronic notices. The system uses an AT89C52 microcontroller interfaced with a GSM modem via a MAX232 level converter. The microcontroller is programmed using Embedded C and interfaces with a PC using Visual Basic. Messages entered on the PC are sent via GSM and displayed on a 16x2 LCD screen. The system provides a wireless solution to remotely update notices with low errors and maintenance.
This document describes a GSM-based anti-theft system for vehicles. The system uses a microcontroller and GSM modem to send SMS alerts to the vehicle owner's phone if the vehicle alarm is triggered. This provides immediate notification even if the thief gets away with the car, allowing the owner to quickly contact authorities. The system components include a microcontroller, GSM modem, and power supply to integrate wireless features and allow the modem to send SMS messages by serially transferring AT commands.
The main aim of this project is to design an SMS driven automatic display notice board which can replace the currently used programmable electronic display. The message to be displayed is sent through a SMS from an authorized sender. The GSM receives the SMS, verifies the sender’s mobile identification pin(MIP) and displays the desired information on LCD.
This document describes an SMS-based notice board display system that uses a GSM modem to receive messages and display them on an LCD screen. An 8051 microcontroller is interfaced with a GSM modem and LCD display to fetch messages from the modem and display them. When a user sends an SMS message to the SIM card in the GSM modem, the microcontroller receives the message through AT commands and displays it on the attached 16x2 LCD screen. Block diagrams, component descriptions, and the circuit diagram are provided to explain the system design and functionality.
This document describes a mini project on an electronic notice board using GSM technology. The notice board receives SMS messages from mobile phones and displays them. Key aspects include:
1. A GSM modem receives SMS messages and transfers them to a microcontroller via serial communication.
2. The microcontroller verifies the password in the SMS and displays the message on an LCD screen.
3. The system could be used by banks, schools, and for advertising to instantly share information via SMS.
The document provides an overview of GSM systems, including:
- A review of first and second generation cellular networks and their focus on coverage over capacity.
- An overview of the key components of GSM architecture, including the mobile station, base station subsystem, and network switching system.
- Descriptions of the coverage and capacity challenges faced by early cellular networks as the subscriber base grew.
Iaetsd wireless electronic notice board using gsmIaetsd Iaetsd
This document describes a wireless electronic notice board system that uses GSM technology to display messages. An authorized user can send an SMS text message from their mobile phone to have it displayed on the electronic board. The system includes a GSM modem connected to a microcontroller which extracts the message and sends it to an LED display board. This allows messages to be shared quickly and remotely without physically updating a notice board. It could be used for applications like education, transportation, advertising and more.
Gsm based campus display system project reportKashyap Shah
Here are the key steps in the information transfer process for this GSM-based campus display system:
1. An authorized user sends an SMS from their mobile phone to the GSM modem connected to the system.
2. The GSM modem receives the SMS via the cellular network.
3. The microcontroller connected to the GSM modem reads the incoming SMS.
4. The microcontroller validates the sender's mobile number to check if they are authorized.
5. If authorized, the microcontroller extracts the message content from the SMS.
6. The microcontroller then encodes/converts the message into a format suitable for display on the LCD.
7. The microcontroller interfaces with
GSM(Global system for mobile communication ) is a second generation cellular standard developed to cater voice services and data delivery using digital modulation.
China had the most cellular subscribers in 2005 with 398 million, representing 19.3% of the global total. The top 15 countries accounted for 68.5% of the world's 2.065 billion cellular subscribers. GSM is now used by over a billion people in more than 200 countries, making it the dominant mobile technology globally. [/SUMMARY]
The document provides an overview of GSM, GPRS, and UMTS mobile wireless technologies. It describes that GSM is a digital cellular standard developed in Europe to provide wireless voice communications. GPRS and UMTS are extensions of GSM that add wireless data capabilities, with UMTS moving networks toward being fully IP-based and supporting broadband services. The key components of a GSM network are the mobile station (phone), base transceiver station (handles radio link), base station controller (manages radio network), and switching centers.
Pat Sims on Community broadband networksAnn Treacy
The document discusses emerging technologies that will impact fiber networks, including next generation architectures, new bandwidth requirements, and video and IP applications. It also summarizes the evolution of fiber networks from early uses connecting central offices to current implementations including passive optical networks, mobile backhaul, and cloud computing. Proper fiber techniques will allow networks built today to transition smoothly to future generations of access electronics and technologies over the next 50 years.
Juniper presented its Universal Access solution for mobile backhaul and aggregation networks. The solution includes the ACX500 for small cell backhaul, the ACX5000 series for pre-aggregation networks, and security gateway options like the SRX5000 and MX104. This provides operators a seamless end-to-end network for transporting mobile traffic from the radio access network to the core while ensuring security and performance.
The document provides an overview of Packet over SONET/SDH (PoS) and related technologies. It discusses the OSI model and various internet protocols like TCP, UDP, IP, and how they relate to PoS. PoS allows efficient transport of IP traffic over SONET/SDH networks. It offers benefits like utilizing existing infrastructure while efficiently transporting various data, voice, and video traffic with less overhead than alternative protocols. The document also covers applications and measurements of PoS performance and connectivity.
This document discusses using a Raspberry Pi-based system to prevent theft of car logos. The system uses a pressure sensor attached to the car logo to detect if someone is trying to remove it. If triggered, the system will first send an alert to the car owner if they are nearby. It will also use GSM to send an SMS message to the owner's phone with a photo of the thief captured by a camera. This provides anti-theft protection for the car logo at an affordable cost using Raspberry Pi and GSM technology to remotely alert the owner even if they are not near the car.
The document provides an overview of the key differences between GSM and CDMA wireless networks. It discusses differences in their radio spectrum usage, network architectures, radio channel technologies, call processing, and evolution to 3G. The network architectures for both include mobile stations, base stations, base station controllers, and mobile switching centers. However, GSM uses TDMA while CDMA uses direct sequence spread spectrum. CDMA allows frequency reuse in all cells while GSM requires frequency assignments between adjacent cells. The document also compares their historical development and technical parameters.
GSM (Global System for Mobile Communications) is the second generation (2G) digital cellular standard developed in Europe in the 1980s. It uses TDMA (Time Division Multiple Access) and FDMA (Frequency Division Multiple Access) to allow multiple users to access the network simultaneously. The key components of a GSM network are the base station, base station controller, mobile switching center, home location register, and visitor location register. GSM networks operate on various frequency bands and use logical channels to transmit different types of information like voice calls, SMS messages, and signaling data. GSM became the most widely used 2G standard globally due to its widespread adoption in Europe and other regions.
This document provides an internship report from Siddhant Bajpai at Bharti Airtel Ltd. covering topics related to mobile communication technologies including optical fiber communication, cellular generations from 1G to 4G, the Global System for Mobile (GSM) network architecture, and components like the base transceiver station, base station controller, mobile switching center, home location register, and visiting location register. The report also includes a chapter on the OSI model and SS7 layers, and examines the call flow process in GSM networks.
This document provides an overview of GSM architecture and components:
1. It describes first and second generation cellular systems, noting the transition to digital with GSM.
2. It outlines the key components of GSM architecture - the mobile station (MS), base station subsystem (BSS) comprising BTS and BSC, and the network switching subsystem (NSS) comprising MSC, HLR, VLR and other registers.
3. It explains the roles of the main functional entities - the MS containing the SIM card, the BTS which provides radio access, the BSC which manages radio resources, and the MSC which acts as the call switch connecting to other networks.
The document summarizes the Voice Internetworking Multiplexer (VIM) product from Marconi. The VIM extends ATM corporate networks to remote sites, enabling toll-quality voice and data integration over the same connection. It has 8 ATM telephony ports, a 155 Mbps ATM OC-3 connection, a T1/E1 WAN link, and a 10Base-T Ethernet port. The VIM provides a cost-effective way to consolidate networks and extend telephony services to remote locations with up to 192 total ports.
The main aim of the project will be to design a SMS driven automatic display toolkit which can replace the currently used programmable electronic display.
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The document contains detailed description for displaying a Message on LED Notice board through SMS service Wirelessly, if facing any problem you can mail me at rajneeshkumarsalgotra@gmail.com with Subject GSM Wireless Notice Board Report_Your Name
This document is a report submitted by Prashant Kumar Gajendra for his MCA 2nd semester seminar on cellular communication. It provides an acknowledgment thanking various sources of information and guidance. It includes an abstract describing an overview of cellular communication and GSM. It also includes various sections on the history, generations, components, and functions of cellular networks.
Global system for mobile communication gsmDAVID RAUDALES
The document provides an overview of the Global System for Mobile Communication (GSM) standard. It discusses the history and evolution of cellular networks leading to GSM. Key aspects of GSM covered include its development from 1982 to 1995, the GSM network elements such as the switching system, base station system, and operation and support system. The switching system manages subscriber services and includes elements like the home location register, mobile switching center, and visitor location register. The base station system handles radio functions and consists of base station controllers and base transceiver stations.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
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This project aims to design an embedded irrigation control system that allows farmers to remotely control water pumps via SMS messages. The system uses a GSM modem to receive SMS commands and control an irrigation pump. This allows farmers to start and stop water pumps without being physically present, saving time, effort and resources. The system was implemented using an ATmega8 microcontroller, GSM modem, relay and other basic electronic components. It is powered by a 5V regulated power supply and allows farmers without literacy skills to easily operate irrigation from any mobile phone.
This document describes a GSM-based anti-theft system for vehicles. The system uses a microcontroller and GSM modem to send SMS alerts to the vehicle owner's phone if the vehicle security is triggered. When the vehicle alarm is activated by forced entry or a motion sensor, the in-vehicle phone will send an SMS to the owner's mobile phone to immediately notify them in case the thief gets away with the car. The system aims to reduce vehicle theft by providing quicker alerts to owners when the security is breached even if the owner is far from the vehicle. The key components are a microcontroller, GSM modem, and power supply to allow wireless SMS communication between the in-vehicle device and the owner's mobile
The document provides information on the Global System for Mobile communications (GSM). It discusses the evolution and standards of GSM, the architecture including components like the BSS, NSS and interfaces. It describes the radio interface technology used in GSM, call flow, and different types of handovers between network elements.
The document provides an overview of the Global System for Mobile (GSM) architecture, including:
1. The GSM architecture consists of mobile stations, the base station subsystem (including base transceiver stations and base station controllers), and the networking switching subsystem (including mobile switching centers, home location registers, and visitor location registers).
2. Mobile stations contain the mobile equipment and subscriber identity module. The base station subsystem handles communication with mobile stations. The networking switching subsystem contains the core network elements for call setup, routing, and subscriber data.
3. GSM digitizes and compresses voice and data for transmission over radio channels between mobile stations and base transceiver stations. It operates in the 900
This document describes a GSM-based campus display system project submitted by three students - Shah Kashyap B., Suthar Pragnesh G., and Rathod Yuvraj S. - to fulfill the requirements for their bachelor's degree. The project involves designing a system using a GSM modem and microcontroller that can receive SMS messages and display messages on an LCD screen for information broadcasting on a college campus. The document provides details about the hardware components used, including the GSM modem, microcontroller, and LCD display, as well as the interfacing between the components and software implementation.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
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Full-RAG: A modern architecture for hyper-personalizationZilliz
Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
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Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
5. 1
ªMobilityª ±
The magic word
Hard to fathom, but it really wasn't all that long ago that even a plain
old telephone was a luxury item. But, as we all know, technology's only
constant is change. In this day and age, many folks need to be accessible everywhere, whether they're at work or play, in the office or at
home. To meet this demand, the GSM standard (Global System for Mobile Communications) for mobile telephony was introduced in the mid1980s. Today, GSM is the most popular mobile radio standard in the
world. A boom is underway, such that many GSM users find life without
their phone practically inconceivable.
Nowadays, when we speak of GSM, we usually mean ªoriginalº GSM ±
also known as GSM900 since 900 MHz was the original frequency
band. To provide additional capacity and enable higher subscriber densities, two other systems were added later: GSM1800 (also DCS1800)
and GSM1900 (also PCS 900). Compared to GSM 900, GSM1800 and
GSM1900 differ primarily in the air interface. Besides using another frequency band, they use a microcellular structure (i.e. a smaller coverage
region for each radio cell). This makes it possible to reuse frequencies
at closer distances, enabling an increase in subscriber density. The disadvantage is the higher attenuation of the air interface due to the higher
frequency. The rest of this booklet will mainly focus on GSM900.
Where now? A few years ago, Michael Jackson sang ª. . . just call my
name and I'll be thereº. While this might seem inconceivable now, it
might become reality sooner than we think, given the rapid pace of
technological evolution. Faced with a whirlwind of speculation, ETSI
3
6. (the telecom standardization authority in Europe) decided to base the
air interface of the planned universal mobile telecommunications system (UMTS) on a mix of WCDMA and TD/CDMA technologies. The infrastructure of the existing GSM networks will most likely be used.
This booklet is intended to provide communications engineers & technicians with basic information about the GSM system ± a starting point
for further study of any given area. A word of warning: Look further if
you need complete GSM system specifications. Research sources are
listed in the appendix. Also: This booklet assumes you, the reader, have
a basic understanding of telecommunications technology.
Enjoy!
Marc Kahabka
4
7. 2
GSM overview
Fig. 1: The Mobile Evolution
Before GSM networks there were public mobile radio networks (cellular). They normally used analog technologies, which varied from country
to country and from manufacturer to another. These analog networks
5
8. did not comply with any uniform standard. There was no way to use a
single mobile phone from one country to another. The speech quality in
most networks was not satisfactory.
GSM became popular very quickly because it provided improved speech
quality and, through a uniform international standard, made it possible to
use a single telephone number and mobile unit around the world. The
European Telecommunications Standardization Institute (ETSI) adopted
the GSM standard in 1991, and GSM is now used in 135 countries.
The benefits of GSM include:
± Support for international roaming
± Distinction between user and device identification
± Excellent speech quality
± Wide range of services
± Interworking (e.g. with ISDN, DECT)
± Extensive security features
GSM also stands out from other technologies with its wide range of
services1:
± Telephony
± Asynchronous and synchronous data services (2.4/4.8/9.6 kbit/s)
± Access to packet data network (X.25)
± Telematic services (SMS, fax, videotext, etc.)
± Many value-added features (call forwarding, caller ID, voice mailbox)
± E-mail and Internet connections
1
6
Available services vary from operator to operator
9. 3
GSM system
architecture
OMC
x.25
x.25
PSPDN
PSTN
ISDN
BSS
MS
BTS
BSC
MSC
Gateway
B ... F
Interface
HLR
VLR
EIR
AUC
Um Interface
Fig. 2
A bis Interface
PCM 2 Mbit/s
G. 703
A Interface
PCM 2 Mbit/s
G. 703
The best way to create a manageable communications system is to
divide it into various subgroups that are interconnected using
standardized interfaces. A GSM network can be divided into three
groups (see Fig. 2): The mobile station (MS), the base station
subsystem (BSS) and the network subsystem.
7
10. They are characterized as follows:
The mobile station
(MS)
A mobile station may be referred to as a ªhandsetº, a ªmobileº, a ªportable terminalº or ªmobile equipmentº ME). It also includes a subscriber
identity module (SIM) that is normally removable and comes in two
sizes. Each SIM card has a unique identification number called IMSI
(international mobile subscriber identity). In addition, each MS is assigned a unique hardware identification called IMEI (international mobile
equipment identity).
In some of the newer applications (data communications in particular),
an MS can also be a terminal that acts as a GSM interface, e.g. for
a laptop computer. In this new application the MS does not look like a
normal GSM telephone.
The seemingly low price of a mobile phone can give the (false) impression that the product is not of high quality. Besides providing a transceiver (TRX) for transmission and reception of voice and data, the
mobile also performs a number of very demanding tasks such as
authentication, handover, encoding and channel encoding.
The base station
subsystem (BSS)
The base station subsystem (BSS) is made up of the base station
controller (BSC) and the base transceiver station (BTS).
The base transceiver station (BTS): GSM uses a series of radio transmitters called BTSs to connect the mobiles to a cellular network. Their
tasks include channel coding/decoding and encryption/decryption. A
BTS is comprised of radio transmitters and receivers, antennas, the interface to the PCM facility, etc. The BTS may contain one or more
8
11. transceivers to provide the required call handling capacity. A cell site
may be omnidirectional or split into typically three directional cells.
. The base station controller (BSC): A group of BTSs are connected
to a particular BSC which manages the radio resources for them.
Today's new and intelligent BTSs have taken over many tasks that
were previously handled by the BSCs.
The primary function of the BSC is call maintenance. The mobile stations normally send a report of their received signal strength to the
BSC every 480 ms. With this information the BSC decides to initiate
handovers to other cells, change the BTS transmitter power, etc.
The network
subsystem
. The mobile switching center (MSC): Acts like a standard exchange
in a fixed network and additionally provides all the functionality
needed to handle a mobile subscriber. The main functions are registration, authentication, location updating, handovers and call routing
to a roaming subscriber. The signaling between functional entities
(registers) in the network subsystem uses Signaling System 7 (SS7).
If the MSC also has a gateway function for communicating with other
networks, it is called Gateway MSC (GMSC).
. The home location register (HLR): A database used for management of
mobile subscribers. It stores the international mobile subscriber identity
(IMSI), mobile station ISDN number (MSISDN) and current visitor location
register (VLR) address. The main information stored there concerns the
location of each mobile station in order to be able to route calls to the mobile subscribers managed by each HLR. The HLR also maintains the services associated with each MS. One HLR can serve several MSCs.
9
12. . The visitor location register (VLR): Contains the current location of
the MS and selected administrative information from the HLR, necessary for call control and provision of the subscribed services, for each
mobile currently located in the geographical area controlled by the
VLR. A VLR is connected to one MSC and is normally integrated into
the MSC's hardware.
. The authentication center (AuC): A protected database that holds a
copy of the secret key stored in each subscriber's SIM card, which is
used for authentication and encryption over the radio channel. The
AuC provides additional security against fraud. It is normally located
close to each HLR within a GSM network.
. The equipment identity register (EIR): The EIR is a database that
contains a list of all valid mobile station equipment within the network, where each mobile station is identified by its international mobile equipment identity (IMEI). The EIR has three databases:
± White list: for all known, good IMEIs
± Black list: for bad or stolen handsets
± Grey list: for handsets/IMEIs that are uncertain
Operation and
Maintenance Center
(OMC)
The OMC is a management system that oversees the GSM functional
blocks. The OMC assists the network operator in maintaining satisfactory operation of the GSM network. Hardware redundancy and intelligent error detection mechanisms help prevent network down-time. The
OMC is responsible for controlling and maintaining the MSC, BSC and
BTS. It can be in charge of an entire public land mobile network (PLMN)
or just some parts of the PLMN.
10
13. 4
Interfaces and
protocols
Fig. 3: OSI Layer structure
in GSM
Note: Numbers in parentheses indicate the relevant
ETSI-GSM Recommendations.
Providing voice or data transmission quality over the radio link is only
part of the function of a cellular mobile network. A GSM mobile can
seamlessly roam nationally and internationally, requiring standardized
call routing and location updating functions in GSM networks. A public
communications system also needs solid security mechanisms to prevent misuse by third parties. Security functions such as authentication,
encryption and the use of Temporary Mobile Subscriber Identities
(TMSIs) are an absolute must.
11
14. Within a GSM network, different protocols are needed to enable the
flow of data and signaling between different GSM subsystems.
Figure 3 shows the interfaces that link the different GSM subsystems
and the protocols used to communicate on each interface.
GSM protocols are basically divided into three layers:
. Layer 1: Physical layer
± Enables physical transmission (TDMA, FDMA, etc.)
± Assessment of channel quality
± Except on the air interface (GSM Rec. 04.04), PCM 30 or ISDN
links are used (GSM Rec. 08.54 on Abis interface and 08.04 on
A to F interfaces).
. Layer 2: Data link layer
± Multiplexing of one or more layer 2 connections
on control/signaling channels
± Error detection (based on HDLC)
± Flow control
± Transmission quality assurance
± Routing
. Layer 3: Network layer
± Connection management (air interface)
± Management of location data
± Subscriber identification
± Management of added services (SMS, call forwarding, conference
calls, etc.)
12
15. 5
The air
interface Um
Fig. 4: GSM Air Interface,
TDMA frame
The International Telecommunication Union (ITU), which manages international allocation of radio spectrum (among many other functions), has
allocated the following bands:
GSM900:
Uplink: 890±915 MHz (= mobile station to base station)
Downlink: 935±960 MHz (= base station to mobile station).
13
16. GSM1800 (previously: DCS-1800):
Uplink: 1710±1785 MHz
Downlink: 1805±1880 MHz
GSM1900 (previously: PCS-1900):
Uplink: 1850±1910 MHz
Downlink: 1930±1990 MHz
The air interface for GSM is known as the Um interface.
Since radio spectrum is a limited resource shared by all users, a
method was devised to divide the bandwidth among as many users as
possible. The method chosen by GSM is a combination of time- and
frequency-division multiple access (TDMA/FDMA). The FDMA part
involves the division by frequency of the (maximum) 25 MHz allocated
bandwidth into 124 carrier frequencies spaced 200 kHz apart. One or
more carrier frequencies are assigned to each base station. Each of
these carrier frequencies is then divided in time, using a TDMA scheme.
The fundamental unit of time in this TDMA scheme is called a burst
period and it lasts approx. 0.577 ms. Eight burst periods are grouped
into a TDMA frame (approx. 4.615 ms), which forms the basic unit for
the definition of logical channels. One physical channel is one burst
period per TDMA frame.
14
18. Several logical channels are mapped onto the physical channels. The
organization of logical channels depends on the application and the
direction of information flow (uplink/downlink or bidirectional). A logical
channel can be either a traffic channel (TCH), which carries user data,
or a signaling channel (see following chapters).
GSM channels
Signaling channels
Traffic channels
Broadcast
channels
full-rate
Fig. 6
half-rate
TCH/F TCH/H
16
Common
control
channels
downlink
uplink
Dedicate
control
channels
slow
BCCH FCCH SCH PCH AGCH RACH SACCH SDCCH
fast
FACCH
19. 5.2 Traffic channels
on the air interface
A traffic channel (TCH) is used to carry speech and data traffic. Traffic
channels are defined using a 26-frame multiframe, or group of 26 TDMA
frames. The length of a 26-frame multiframe is 120 ms, which is how
the length of a burst period is defined (120 ms divided by 26 frames
divided by 8 burst periods per frame). Out of the 26 frames, 24 are
used for traffic, 1 is used for the slow associated control channel
(SACCH) and 1 is currently unused (see Fig. 5). TCHs for the uplink and
downlink are separated in time by 3 burst periods, so that the mobile
station does not have to transmit and receive simultaneously, thereby
simplifying the electronic circuitry. This method permits complex antenna duplex filters to be avoided and thus helps to cut power consumption.
In addition to these full-rate TCHs (TCH/F, 22.8 kbit/s), half-rate TCHs
(TCH/H, 11.4 kbit/s) are also defined. Half-rate TCHs double the capacity of a system effectively by making it possible to transmit two calls
in a single channel. If a TCH/F is used for data communications, the
usable data rate drops to 9.6 kbit/s (in TCH/H: max. 4.8 kbit/s) due to
the enhanced security algorithms. Eighth-rate TCHs are also specified,
and are used for signaling. In the GSM Recommendations, they are
called stand-alone dedicated control channels (SDCCH).
17
20. 5.3 Signaling
channels on the
air interface
The signaling channels on the air interface are used for call establishment, paging, call maintenance, synchronization, etc. There are 3 groups
of signaling channels:
. The broadcast channels (BCH): Carry only downlink information
and are responsible mainly for synchronization and frequency correction. This is the only channel type enabling point-to-multipoint communications in which short messages are simultaneously transmitted
to several mobiles.
The BCHs include the following channels:
± The broadcast control channel (BCCH): General information, cellspecific; e.g. local area code (LAC), network operator, access
parameters, list of neighboring cells, etc. The MS receives signals
via the BCCH from many BTSs within the same network and/or
different networks.
± The frequency correction channel (FCCH): Downlink only; correction of MS frequencies; transmission of frequency standard to MS;
it is also used for synchronization of an acquisition by providing
the boundaries between timeslots and the position of the first timeslot of a TDMA frame.
± The synchronization channel (SCH): Downlink only; frame synchronization (TDMA frame number) and identification of base
station. The valid reception of one SCH burst will provide the MS
with all the information needed to synchronize with a BTS.
18
21. . The common control channels (CCCH): A group of uplink and
downlink channels between the MS card and the BTS. These channels are used to convey information from the network to MSs and
provide access to the network. The CCCHs include the following
channels:
± The paging channel (PCH): Downlink only; the MS is informed by
the BTS for incoming calls via the PCH.
± The access grant channel (AGCH): Downlink only; BTS allocates a
TCH or SDCCH to the MS, thus allowing the MS access to the
network.
± The random access channel (RACH): Uplink only; allows the MS
to request an SDCCH in response to a page or due to a call; the
MS chooses a random time to send on this channel. This creates
a possibility of collisions with transmissions from other MSs.
The PCH and AGCH are transmitted in one channel called the paging
and access grant channel (PAGCH). They are separated by time.
. The dedicated control channels (DCCH): Responsible for e.g.
roaming, handovers, encryption, etc.
The DCCHs include the following channels:
± The stand-alone dedicated control channel (SDCCH): Communications channel between MS and the BTS; signaling during call setup
before a traffic channel (TCH) is allocated;
± The slow associated control channel (SACCH): Transmits continuous measurement reports (e.g. field strengths) in parallel to oper19
22. ation of a TCH or SDCCH; needed, e.g. for handover decisions; always allocated to a TCH or SDCCH; needed for ªnon-urgentº procedures, e. g. for radio measurement data, power control (downlink
only), timing advance, etc.; always used in parallel to a TCH or
SDCCH.
± The fast associated control channel (FACCH): Similar to the
SDCCH, but used in parallel to operation of the TCH; if the data
rate of the FACCH is insufficient, ªborrowing modeº is used:
Additional bandwidth is borrowed from the TCH; this happens for
messages associated with call establishment authentication of the
subscriber, handover decisions, etc.
Almost all of the signaling channels use the ªnormal burstº format
(see section 5.4 Burst formats), except for the RACH (Random Access
Burst), FCCH (Frequency Correction Burst) and SCH (SynCHronization
Burst) channels.
5.4 Burst formats
A timeslot is a 576 ms time interval, i.e. 156.25 bits duration, and its
physical contents are known as a burst. Five different types of bursts
exist in the system. They are distinguished by different TDMA frame
divisions.
The normal burst (NB): Used to carry information on traffic and control
channels, except for RACH. It contains 116 encrypted bits.
The frequency correction burst (FB): Used for frequency synchronization of the mobile. The contents of this burst are used to calculate an
20
23. unmodulated, sinusoidal oscillation, onto which the synthesizer of the
mobiles is clocked.
The synchronization burst (SB): Used for time synchronization of the
mobile. It contains a long training sequence and carries the information
of a TDMA frame number.
The access burst (AB): Used for random access and characterized
by a longer guard period (256 ms) to allow for burst transmission from
a mobile that does not know the correct timing advance at the first
access to a network (or after handover).
The dummy burst (DB): Transmitted as a filler in unused timeslots of
the carrier; does not carry any information but has the same format as
a normal burst (NB).
21
24. 5.5 Protocols on the
air interface
. Layer 1 (GSM Rec. 04.04): The physical properties of the Um interface have already been described.
. Layer 2 (GSM Rec. 04.05/06): Here, the LAP-Dm protocol is used
(similar to ISDN LAP-D). LAP-Dm has the following functions:
± Connectionless transfer on point-to-point and point-to-multipoint
signaling channels,
± Setup and take-down of layer 2 connections on point-to-point
signaling channels,
± Connection-oriented transfer with retention of the transmission
sequence, error detection and error correction.
. Layer 3 (GSM Rec. 04.07/08): Contains the following sublayers which
control signaling channel functions (BCH, CCCH and DCCH):
± Radio resource management (RR): The role of the RR management layer is to establish and release stable connection between
mobile stations (MS) and an MSC for the duration of a call, and to
maintain it despite user movements. The following functions are
performed by the MSC:
± Cell selection,
± Handover,
± Allocation and take-down of point-to-point channels,
± Monitoring and forwarding of radio connections,
± Introduction of encryption,
± Change in transmission mode.
22
25. ± Mobility management (MM) handles the control functions
required for mobility, e.g.:
± Authentication,
± Assignment of TMSI,
± Management of subscriber location.
± Connection management (CM) is used to set up, maintain and
take down calls connections; it is comprised of three subgroups:
± Call control (CC): Manages call connections,
± Supplementary service support (SS): Handles special services,
± Short message service support (SMS): Transfers brief texts.
Neither the BTS nor the BSC interpret CM and MM messages. They
are simply exchanged with the MSC or the MS using the direct transfer
application part (DTAP) protocol on the A interface. RR messages are
mapped to or from the base station system application part (BSSAP) in
the BSCREF for exchange with the MSC.
23
26. 6
The Abis
interface
Fig. 7: GSM Abis Interface,
PCM timeslot layout
The Abis interface lies within the base station subsystem (BSS) and
represents the dividing line between the BSC function and the BTS.
The BSC and BTS can be connected using leased lines, radio links or
metropolitan area networks (MANs).
Basically, two channel types exist between the BSC and BTS:
± Traffic channels (TCH): Can be configured in 8, 16 and 64 kbit/s
formats and transport user data,
24
27. ± Signaling channels: Can be configured in 16, 32, 56 and 64 kbit/s
formats and are used for signaling purposes between the BTS and
BSC.
Each transceiver (TRX) in a BSC generally requires a signaling channel
on the Abis interface. The positioning of the user data frames (T = Traffic) and signaling data frames (S = Signaling) varies from manufacturer
to manufacturer and from system to system. The only requirement is
that the FAS/NFAS frame must be in timeslot 0. A signaling channel
can run at either 16 kbit/s (sub-channel signaling) or 64 kbit/s.
25
28. 6.1 The TRAU frame
Fig. 8
The TRAU (Transcoder Rate Adapter Unit) frame is the transport unit for
a 16 kbit/s traffic channel (TCH) on the Abis interface. It uses 13.6 kbit/s
for user data and 2.4 kbit/s for inband signaling, timing and synchronization. It is here that the positions at which the signaling and data bits
occur are determined.
26
29. The bit names shown in Fig.
(yellow or blue background):
C... bits:
T... bits:
D... bits:
8 are interpreted as follows:
Synchronization bits
Control/signaling bits
Time alignment (TA) bits
User data bits (payload)
The TRAU frame specifications are as follows:
Total bits per frame: 320
Synchronization bits: 25
Control bits: C1 to 15
C17 to 21 (frame dependent and for future applications)
There are four variants for the C, D and T bits,
depending on the frame type:
1. Speech frame
Data bits:
D1 to 260
Control bits:
C16 to 21
TA bits:
T1 to 4
2. O&M frame
Data bits:
D1 to 264
Spare bits:
S1 to 6
3. Data frame
Data bits:
D1 to 252
First bit of odd octets (5 to 39) is ª1º
4. Idle speech frame
Like the speech frame, but all data bits are set to ª1º
27
30. The protocol used on the Abis interface is LAPD, which is adapted from
ISDN. LAPD provides the following frame types that can be divided into
three groups:
± the unnumbered frames (SABM, DISC, UA, DM, UI),
± the information transfer frame (I)
± the supervisory frames (RR, RNR, REJ, FRMR).
In addition to the radio signaling procedures the Abis interface also provides a means of transport for operation and maintenance procedures
for BTSs, as well as a transport mechanism for Layer 2 management
procedures inherited directly from ISDN standards.
6.2 Protocols on the
Abis interface
The following protocols are used:
. Layer 1 (GSM Rec. 08.54): 2.048 Mbit/s (ITU-T: E1) or 1.544 Mbit/s
(ANSI: T1) PCM facility with 64/32/16 kbit/s signaling channels and
16 kbit/s traffic channels (4 per timeslot)
. Layer 2 (GSM Rec. 08.56): Here, the LAP-D protocol is used as the
transport mechanism for data messaging between the BTS and BSC.
Within GSM the SAPI refers to the link identifier transmitted in the
LAPD protocol that was inherited from ISDN.
. Layer 3 (GSM Rec. 08.58/04.08): BTS management (BTSM) works
mainly in this layer. BTSM distinguishes three logical signaling
connections with the SAPI (Service Access Point Identifier). SAPI 0 is
used by all messages coming from or going to the radio interface.
SAPI 62 provides O&M message transport between the BTS and
BSC. SAPI 63 is used for dynamic management of TEIs as well as for
28
31. layer 2 management functions. The addition of another field to the
LAPD link layer address is for the TEIs. The TEIs that provide addressing of the TRXs (transmitters and receivers) for the BTS are as follows:
1. Radio signaling link (RSL): Traffic management; used for signaling between the BSC and BTS (non-transparent messages,
e.g. RR) and transmission of signaling information on the air
interface in the form of transparent messages (CM and MM
messages)
2. Operating & maintenance link (OML): Network management;
used to monitor the operating status of the TRXs or BTS; OML
messages have priority over other layer 2 messages.
3. Layer 2 management link (L2ML): Layer 2 management; controls
the TEI management and addressing procedures (allocation,
de-allocation of BTS internal transceiver [TRX] addresses)
29
32. 7
The A interface
The A interface lies between the BSC and MSC. If the BSC contains
the transcoder equipment (TCE), a traffic channel (TCH) occupies a
complete 64 kbit/s timeslot in the 2 Mbit/s or 1.544 Mbit/s PCM link
(layer 1, GSM Rec. 08.04). Out of 32 available timeslots on the PCM
link, a maximum of 30 traffic channels can be operated simultaneously,
since at least 2 timeslots are needed for control and signaling purposes
(TS0 for FAS/NFAS and another TS for signaling, usually TS16) on PCM
facilities. One signaling channel supports many 64 kbit/s PCM facilities
between one BSC and the MSC. Normally two active 64 kbit/s timeslots are used for this purpose.
If the MSC is equipped with a TCE, the TCHs are converted from
64 kbit/s to 16 kbit/s in the transcoder equipment. If the BCS does not
contain a TCE, then the TCHs are 16 kbit/s on the A interface.
Between the BSC and MSC, the TCHs are ªrecordedº from 64 kbit/s to
16 kbit/s in the transcoder equipment (TCE).
7.1 Protocols on
the A interface
The signaling protocol (layer 2+3) between the BSC and MSC is based
on the SS7 standard, but is transmitted along with the user data within
the PCM facility. Normally timeslot 16 (TS16) of the 64 kbit/s frame is
used.
The following protocols are employed:
. Layer 1 (GSM Rec. 08.04): 2.048 Mbit/s (ITU-T: E1) or 1.544 Mbit/s
(ANSI: T1) PCM link.
. Layer 2 (GSM Rec. 08.06): Here, SS7-based protocols are used for
layer 2; the message transfer part (MTP) protocol (responsible for
30
33. transmission security between the BCS and MSC) and the signaling
connection control part (SCCP) protocol (allows global addressing of
network elements and thus offers a service corresponding to the exchange layer). MTP and SCCP also perform layer 3 functions. SCCP
is used to transport DTAP and base station management application
part (BSSMAP) messages on the A interface, ensuring both conectionless and connection-oriented message flows. The connections
can be related to a specific MS or radio channel.
An SCCP connection can be initiated by a mobile station (MS) or an MSC.
An SCCP connection can involve the following protocols:
. From the MS:
± MM: CM service request
± RR: Paging response
± MM: Location updating request
± MM: CM re-establishment request.
. From the MSC: Initiation of an ªexternal handoverº
(BSSMAP: handover request).
The MSC always manages an SCCP connection.
. Layer 3 (GSM Rec. 08.08): Contains the base station system application part (BSSAP) protocol. This layer has multiple parts on the
MSC end:
. The base station management application part (BSSMAP) protocol
is the counterpart to the RR protocol on the air interface.
. The direct transfer application part (DTAP) protocol transmits CC
and MM messages and is transmitted transparently through the
BTS and BSC.
31
34. 8
MSC-based
interfaces
Fig. 9
All of the interfaces around the MSC use SS7-based protocols. The B,
C, D, F and G interfaces are referred to as MAP interfaces. These connect either the MSC to registers or registers to other registers. The E
interface supports the MAP protocol and calls setup protocols (ISUP/
TUP). This interface connects one MSC to another MSC within the
same network or to another network's MSC. They are designated as
follows (protocols are explained in section 8.1 MSC protocols):
.
.
.
.
.
.
B interface: between MSC and VLR (use MAP/TCAP protocols)
C interface: between MSC and HLR (MAP/TCAP)
D interface: between HLR and VLR (MAP/TCAP)
E interface: between two MSCs (MAP/TCAP + ISUP/TUP)
F interface: between MSC and EIR (MAP/TCAP)
G interface: between VLRs (MAP/TCAP).
32
35. Fixed network interfaces:
. via TUP protocol: between
. via ISUP protocol: between
provides
. via INAP protocol: between
MSC and analog/digital networks
MSC and analog/digital networks;
more features than TUP
MSC and IN.
The SCCP protocol provides connectionless message transport to and
from the GSM network databases for TCAP and MAP messaging.
Here, two connection types are also distinguished:
. Circuit-related call control: Related to ISUP and TUP
. Non circuit-related call control: The mobile application part (MAP)
protocol is used here, allowing implementation of functions such as
location updating/roaming, SMS delivery, handover, authentication and
incoming call routing information. The MAP protocol uses the transaction capability application part (TCAP) protocol to transfer real-time
information (between MSCs, HLRs and VLRs).
8.1 MSC protocols
MAP (Mobile Application Part): (GSM Rec. 09.02) Used to control
queries to the different databases in the mobile radio network (HLR,
VLR and EIR). MAP responsibilities include access and location management (e.g. where is the called subscriber currently?), MSC-MSC
handover, security functions, O&M, SMS and supplementary services.
TCAP (Transaction Capabilities Application Part): Provides universal
calls and functions for handling requests to distributed application
processes.
33
36. ISUP (ISDN User Part): Controls interworking (e.g. call setup/takedown) between PLMNs and other networks, and provides the same basic functionalities as TUP.
INAP (Intelligent Network Application Part): Implements intelligent
supplementary services (e.g. free call, time-dependent routing functions
in a central service center).
TUP (Telephone User Part): Implements interworking between PLMNs
and other networks. TUP is normally used to provide international connections and is slowly being replaced by ISUP.
34
38. The incoming call is passed from the fixed network to the gateway
MSC (GMSC) (1). Then, based on the IMSI numbers of the called party,
its HLR is determined (2). The HLR checks for the existence of the
called number. Then the relevant VLR is requested to provide a mobile
station roaming number (MSRN) (3). This is transmitted back to the
GMSC (4). Then the connection is switched through to the responsible
MSC (5). Now the VLR is queried for the location range and reachability
status of the mobile subscriber (6). If the MS is marked reachable, a
radio call is enabled (7) and executed in all radio zones assigned to the
VLR (8). When the mobile subscriber telephone responds to the page
request from the current radio cell (9), all necessary security procedures
are executed (10). If this is successful, the VLR indicates to the MSC
(11) that the call can be completed (12).
36
39. 10 Test and
measurement
problems
in GSM
Fig. 11
As you can see from the previous sections, GSM technology is very
complex. Naturally, such a technology is a challenge to install, commission, manage and optimize. The following section will consider some
sample network problems1.
1
For more information on GSM test applications, see the WG Application Notes
(available upon request)
37
40. Due to the limited nature of resources (not to mention their high cost),
network optimization is becoming a more and more critical economic
factor. To get a handle on network performance, network utilization,
subscriber behavior and quality of service (QoS), the following test
methods are useful:
Traffic analysis: Here, the contents of signaling channels in an E1 or
T1 PCM frame are monitored and analyzed on the Abis and A interfaces
of the GSM network. It does not matter what type traffic the various
timeslots transport (speech, data or signaling) since all contribute
equally to traffic loading.
Bit error ratio test (BERT): A BERT involves bit error measurement at
the PCM level and the GSM-specific level (TRAU frame ± TRAU: Transcoder and Rate Adapter Unit). The PCM bit error ratio (BER) is of interest to GSM operators who need to verify the quality of leased lines
from fixed network operators.
At the GSM level, by evaluating the control bits in the TRAU, a bit error
probability can be determined (uplink) during actual communications
(in-service). More accurate BER measurement requires out-of-service
simulation in which the 260 data bits in the TRAU frame are checked
using a pseudo-random bit sequence (PRBS).
38
41. Alarm monitoring: This test type checks all PCM links for layer 1
alarms, including:
± No signal,
± Alarm indication signal (AIS),
± No synchronization,
± Remote alarm,
± CRC alarm.
Network quality test: Includes a number of diverse measurements that
work together to provide an indication of network quality and reveal
potential areas for improvement. This includes:
± Island problems (see Fig. 11),
± Detection of coverage holes,
± Interference,
± Network load regarding signaling and traffic,
± Handover failures,
± Receive level (RXLEV) surveillance,
± Bit error ratio of a BTS (RXQUAL),
± Multipath interference and propagation delays,
± Frequency interference (due to frequency reuse),
± Call completion/disconnect rate,
± System overload.
Optimally qualifying a GSM network requires extensive protocol analysis
in the Abis and SS7-based interfaces. This is due to the intersection of
the GSM and SS7 protocol worlds, as described in section 8.1 ªMSC
protocolsº.
39
42. System features
This section provides a brief description of the GSM network
features.
Roaming:
The roaming feature allows a user to make and receive calls in any
GSM network and to use the same user-specific services worldwide1.
This requires a roaming agreement between the individual operators.
With worldwide roaming the MS is accessible under the same phone
number everywhere.
Handover:
In a cellular network, the radio and fixed voice connections are not permanently allocated for the duration of a call. Handover, or handoff as it
is called in North America, means switching an ongoing call to a different channel or cell. The execution and measurements required for
handover are a basic function of the RR protocol layer.
There are four different types of handovers in GSM, which involve
transferring a connection between:
. Channels (timeslots) in the same cell (intra-BTS handover)
. Cells under the control of the same BSC (inter-BTS handover).
. Cells under the control of different BSCs, but belonging to the same
MSC (inter-BSC handover)
. Cells under the control of different MSCs (inter-MSC handover)
1
Identical carrier frequencies (900/1800/1900) are required, therefore, or the telephone
needs to support the desired frequency. Dual-band mobiles that support several fre-
40
43. quency bands are becoming increasingly popular in this connection.
The first two types of handover involve only one base station controller
(BSC). To save signaling bandwidth, they are managed by the BSC
without involving the MSC, except to notify it upon completion of the
handover. The last two types of handover are handled by the MSCs
involved. An important aspect of GSM is that the original MSC, the
anchor MSC, remains responsible for most call-related functions, with
the exception of subsequent inter-BSC handovers under the control of
the new MSC, called the relay MSC.
Handovers can be initiated by either the BSC or the MSC (as a means
of traffic load balancing). During its idle timeslots, the mobile scans the
broadcast control channel of up to 16 neighboring cells, and forms a
list of the six best candidates for possible handover, based on the
received signal strength. This information is passed to the BSC and
MSC, at least once per second, and is used by the handover algorithm.
The decision on when to initiate a handover is a function of the
following parameters:
± receive quality,
± receive level.
Successful handovers in GSM can take place at propagation speeds of
up to 250 km/h.
Multipath equalization:
At the 900 MHz range, radio waves bounce off everything ± buildings,
41
44. hills, cars, airplanes, etc. Many reflected signals, each with a different
phase, can reach an antenna (also known as ªmultipath propagationº).
Equalization is used to extract the desired signal from the unwanted
reflections. It works by finding out how a known transmitted signal is
modified by multipath fading, and constructing an inverse filter to
extract the rest of the desired signal. This known signal is the 26-bit
training sequence transmitted in the middle of every time-slot burst.
The actual implementation of the equalizer is not specified in the GSM
specifications.
Frequency hopping:
The mobile station has to be frequency-agile, meaning it can move
between different frequencies in order to transmit and receive data, etc.
A normal handset is able to switch frequencies 217 times per second.
GSM makes use of this frequency agility to implement slow frequency
hopping, where the mobile and the BTS transmit each TDMA frame on
a different carrier frequency. The frequency hopping algorithm is broadcast on the broadcast control channel. Since multipath fading is dependent on the carrier frequency, slow frequency hopping helps alleviate
the problem. In addition, co-channel interference is in effect randomized. The broadcast and common control channels are not subject to
frequency hopping and are always transmitted on the same frequency.
Discontinuous transmission (DTX):
To reduce the MS's power consumption and minimize interference on
the air interface, user signal transmission is interrupted during pauses
in speech. ªComfort noiseº is artificially generated by the MS to avoid
42
46. Discontinuous
reception (DRX):
Another method used to conserve power at the mobile station is discontinuous reception. The paging channel, used by the base station to
signal an incoming call, is structured into sub-channels. Each mobile
station needs to listen only to its own sub-channel. In the time between
successive paging sub-channels, the mobile can go into sleep mode,
when almost no power is used.
Power control:
Several classes of mobile stations are defined in the GSM specifications, according to their peak transmitter power. To minimize co-channel interference and to conserve power, both the mobiles and the base
transceiver stations operate at the lowest power level that will maintain
an acceptable signal quality. Power levels can be stepped up or down
in steps of 2 dBm from the peak power for the class down to a minimum of 13 dBm (20 milliwatts for MS).
The mobile station and BTS continually measure the signal strength or
signal quality (based on the bit error ratio), and pass the information to
the base station controller, which ultimately decides if and when the
power level should be changed.
Short Message
Service (SMS)
SMS offers message delivery (similar to ªtwo-way-pagingº) that is guaranteed to reach the MS. If the GSM telephone is not turned on, the
message is held for later delivery. Each time a message is delivered
to an MS, the network expects to receive an acknowledgement
from this MS that the message was correctly received. Without a posi44
47. tive acknowledgement the network will re-send the message or store it
for later delivery. SMS supports messages up to 160 characters in
length that can be delivered by any GSM network around the world
wherever the MS is able to roam.
Call Waiting (CW)
CW is a network-based feature that must also be supported by the
GSM telephone (MS). With CW, GSM users with a call in progress will
receive an audible beep to alert them that there is an incoming call for
the MS. The incoming call can be accepted, sent to voice mail or rejected. If the incoming call is rejected, the caller will receive a busy
signal. Once the call is accepted, the original call is put on hold to allow
a connection to the new incoming call.
Call Hold (CH)
CH must be supported by the MS and the network. It allows the MS to
ªparkº an ªin progress callº, to make additional calls or to receive incoming calls.
Call Forwarding (CF)
This is a network-based feature that can be activated by the MS. CF
allows calls to be sent to other numbers under conditions defined by
the user. These conditions can be either unconditional or dependent on
certain criteria (no answer, busy, not reachable).
Calling Line ID
Calling Line ID must be supported by the GSM network and the telephone. The GSM telephone displays the originating telephone number
of incoming calls. This feature requires the caller's network to deliver
the calling line ID (telephone no.) to the GSM network.
45
48. Mobility
Management (MM)
The GSM network keeps track of which mobile telephones are powered
on and active in the network. To provide as efficient call delivery as
possible, the network keeps track of the last known location of the MS
in the VLR and HLR. Radio sites connected to the MSC are divided into
groups called ªlocation areasº. When a call is designated for an MS,
the network looks for the MS in the last known location area.
Authentication
Authentication normally takes place when the MS is turned on with
each incoming call and outgoing call. A verification that the »Ki« (security code) stored in the AuC matches the »Ki« stored in SIM card of the
MS completes this process.
The user must key in a PIN code on the handset in order to activate
the hardware before this automatic procedure can start.
46
49. 11 Outlook
In early 1998, the ETSI standardization committee made up its mind on
the future, third-generation mobile radio standard, known as the universal mobile telecommunications system (UMTS). UMTS should support
all forms of mobile, satellite-based and fixed-network-based telecommunications. The user should be able to use all services (voice, data,
multimedia, etc.) in each of the stated areas.
ETSI agreed to use a combination of wideband code division multiple
access (W-CDMA) and time division multiple access (TD/CDMA) on the
air interface. W-CDMA will be used to cover larger areas and TD/CDMA
for local (indoor) applications. CDMA technology holds the promise of a
higher channel capacity and lower power consumption with GSM-like
speech quality. Costly frequency planning like that required in GSM networks is unnecessary in CDMA networks.
Now that Europe has made its choice, work is underway towards
worldwide acceptance of the UMTS standard. There is still no agreement on the network architecture, but network operators naturally hope
to reuse existing GSM networks to save money.
Besides straightforward telephony, data communication is also important in UMTS. Here, the catch phrase is ªmobile multimediaº: It should
be possible in the future to operate data-intensive applications such as
video conferencing via a mobile unit.
47
50. 12 GSM glossary
AB
AGCH
AIS
AMPS
AuC
BCCH
BCH
BER
BERT
BSC
BSSAP
BSSMAP
BTS
BTSM
CC
CCCH
CDMA
CM
CRC
CT0/1/2
D-AMPS
DB
DCCH
DCS 1800
DECT
DRX
48
Access Burst
Access Grant CHannel
Alarm Indication Signal
Advanced Mobile Telephone Service
Authentication Center
Broadcast Control CHannel
Broadcast CHannels
Bit Error Rate
Bit Error Rate Test
Base Station Controller
Base Station System Application Part
Base Station Management Application Part
Base Transceiver Station
BTS Management
Call Control
Common Control CHannels
Code Division Multiple Access
Connection Management
Cyclic Redundancy Check
(Standards for) Cordless Telephony 0/1/2
Dual Mode AMPS
Dummy Burst
Dedicated Control CHannels
Digital Cellular System 1800 (today: GSM1800)
Digital Enhanced Telecommunications System
Discontinuous reception
51. DTAP
DTX
EIR
ETSI
FACCH
FAS
FB
FCCH
FDMA
GMSC
GPRS
GSM
HDLC
HLR
IMEI
IMSI
IN
INAP
ISDN
ISUP
L2ML
LAP-D
LAP-Dm
MAN
MAP
ME
49
Direct Transfer Application Part
Discontinuous Transmission
Equipment Identity Register
European Telecommunications Standards Institute
Fast Associated Control CHannel
Frame Alignment Signal
Frequency correction Burst
Frequency Correction CHannel
Frequency Division Multiple Access
Gateway MSC
General Packet Radio Service
Global System for Mobile Communications
High Level Data Link Control
Home Location Register
International Mobile Equipment Identity
International Mobile Subscriber Identity
Intelligent Network
Intelligent Network Application Part
Integrated Services Digital Network
ISDN User Part
Layer 2 Management Link
Link Access Protocol for the (ISDN) D-Channel
LAP-D for the GSM Um Interface
Metropolitan Area Network
Mobile Application Part
Mobile Equipment
52. MM
MS
MSC
MSISDN
MSRN
MTP
NB
NFAS
NMT
O&M
OMC
OML
PCH
PCM
PCS1900
PHS
PLMN
PRBS
QoS
RACH
RR
RSL
RXLEV
RXQUAL
SACCH
SB
50
Mobility Management
Mobile Station
Mobile Switching Center
MS ISDN number
Mobile Station Roaming Number
Message Transfer Part
Normal Burst
Non-FAS
Nordic Mobile Telephone Network
Operations and Maintenance
Operation and Maintenance Center
Operating & Maintenance Link
Paging CHannel
Pulse Code Modulation
Personal Communications System 1900 (today: GSM1900)
Personal Handyphone System
Public Land Mobile Network
Pseudo Random Bit Sequence
Quality of Service
Random Access CHannel
Radio Resource management
Radio Signaling Link
Received Signal Level
Received Signal Quality
Slow Associated Control CHannel
Synchronization Burst
53. SCCP
SCH
SDCCH
SIM
SMS
SMS
SS
SS7
TA
TACS
TCAP
TCH
TD/CDMA
TDMA
TMSI
TRAU
TRX
TS
TUP
Um
UMTS
VLR
WCDMA
51
Signaling Connection Control Part
Synchronization CHannel
Stand-alone Dedicated Control CHannel
Subscriber Identity Module
Short Message Service
Short Message Service Support
Supplementary Service Support
Signaling System Number 7
Time Alignment
Total Access Communication System
Transaction Capabilities Application Part
Traffic CHannel
Time Division Code Division Multiple Access
Time Division Multiple Access
Temporary Mobile Subscriber Identity
Transcoding and Rate Adaptation Unit
Transceiver
Timeslot
Telephone User Part
Air interface in GSM
Universal Mobile Telecommunications System
Visitor Location Register
Wideband Code Division Multiple Access
54. 13 Bibliography
1. GSM-Technik und Messpraxis [GSM technology and practical testing
± in German] ± Redl/Weber, Franzis', Poing
2. Microcells in mobile communications ± Tibor Rako, Gyozo Drozdy;
Â
Ä Ä
http://www.pgsm.hu/english/gsm/more.html
3. Overview of the Global System for Mobile Communications ± John
Scourias; University of Waterloo;
http://ccnga.uwaterloo.ca/~jscouria/GSM/gsmreport.html
4. Mobilkommmunikation, Hochschulkolleg [Mobile communications,
High-school textbook ± in German] ± Ulrich Bochtler, Walter Buck,
Eberhard Herter; Steinbeis-Transferzentrum, Kommunikationszentrum
Esslingen
5. The Global System for Mobile Communications ± Michel Mouly,
Marie-Bernadette Paulet; Palaiseau, France
6. Vermittlungstechnik und Schnittstellen [Switching technology and
interfaces ± in German] ± Ulrich Bochtler; Steinbeis-Transferzentrum,
Kommunikationszentrum Esslingen
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