At the beginning of the 1990s, GSM, the Global System for Mobile Communications triggered an unprecedented change in the way people communicate with each other. While earlier analog wireless systems were used by only a few people, GSM was used by over 1.5 billion subscribers worldwide at the end of 2005. This has mostly been achieved by the steady improvements in all areas of telecommunication technology and due to the steady price reductions for both infrastructure equipment and mobile phones.
Standards
As many telecom companies compete globally for orders of telecommunication network operators, standardization of interfaces and procedures is necessary. Without standards, which are defined by the International Telecommunication Union (ITU), it would not be possible to make phone calls internationally and network operators would be bound to the supplier they initially select for the delivery of their network components. One of the most important ITU standards is the signaling system number 7 (SS-7), which is used for call routing.
GSM, for the first time, set a common standard for Europe for wireless networks, which has also been adopted by many countries outside Europe. This is the main reason why subscribers can roam in GSM networks across the world that have roaming agreements with each other. The common standard also substantially reduces research and development costs as hardware and software can now be sold worldwide with only minor adaptations for the local market. The European Telecommunication Standards Institute (ETSI), which is also responsible for a number of other standards, was the main body responsible for the creation of the GSM standard. The ETSI GSM standards are composed of a substantial number of standards documents each called a technical specification (TS), which describe a particular part of the system.
Transmission Speeds
The smallest transmission speed unit in a telecommunication network is the digital signal level 0 (DS0) channel. It has a fixed transmission speed of 64 kbit/s. Such a channel can be used to transfer voice or data and thus it is usually not called a speech channel but simply referred to as a user data channel. The reference unit of a telecommunication network is an E-1 connection in Europe and a T-1 connection in the United States, which use either a twisted pair or coaxial copper cable. The gross data rate of an E-1 connection is 2.048 Mbit/s and 1.544 Mbit/s for a T-1. An E-1 is divided into 32 timeslots of 64 kbit/s each while a T-1 is divided into 24 timeslots of 64 kbit/s each. One of the timeslots is used for synchronization which means that 31 timeslots for an E-1 or 23 timeslots for a T-1 respectively can be used to transfer data. In practice, only
29 or 30 timeslots are used for user data transmission while the rest (usually one or two) are used for SS-7 signaling data.
Standards
As many telecom companies compete globally for orders of telecommunication network operators, standardization of interfaces and procedures is necessary. Without standards, which are defined by the International Telecommunication Union (ITU), it would not be possible to make phone calls internationally and network operators would be bound to the supplier they initially select for the delivery of their network components. One of the most important ITU standards is the signaling system number 7 (SS-7), which is used for call routing.
GSM, for the first time, set a common standard for Europe for wireless networks, which has also been adopted by many countries outside Europe. This is the main reason why subscribers can roam in GSM networks across the world that have roaming agreements with each other. The common standard also substantially reduces research and development costs as hardware and software can now be sold worldwide with only minor adaptations for the local market. The European Telecommunication Standards Institute (ETSI), which is also responsible for a number of other standards, was the main body responsible for the creation of the GSM standard. The ETSI GSM standards are composed of a substantial number of standards documents each called a technical specification (TS), which describe a particular part of the system.
Transmission Speeds
The smallest transmission speed unit in a telecommunication network is the digital signal level 0 (DS0) channel. It has a fixed transmission speed of 64 kbit/s. Such a channel can be used to transfer voice or data and thus it is usually not called a speech channel but simply referred to as a user data channel. The reference unit of a telecommunication network is an E-1 connection in Europe and a T-1 connection in the United States, which use either a twisted pair or coaxial copper cable. The gross data rate of an E-1 connection is 2.048 Mbit/s and 1.544 Mbit/s for a T-1. An E-1 is divided into 32 timeslots of 64 kbit/s each while a T-1 is divided into 24 timeslots of 64 kbit/s each. One of the timeslots is used for synchronization which means that 31 timeslots for an E-1 or 23 timeslots for a T-1 respectively can be used to transfer data. In practice, only
29 or 30 timeslots are used for user data transmission while the rest (usually one or two) are used for SS-7 signaling data.
1 comment:
"Such a channel can be used to transfer voice or data and thus it is usually not called a speech channel but simply referred to as a user data channel."
Does this mean that an SMS and a phone call both follow the same mechanism of transmitting information?
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