TTM4133: Mobile Networks and Services
# Preface
This compendium aims to explain the most important concepts in the subject. The content is mostly based onthe lecture slides and the book: "From GSM to LTE-Advanced PRO and 5G".
The course focuses on: GSM, GPRS, UMTS, LTE, SIP & IMS, 5G and Over the Top Services. The compendium is structured around explaining each of these items in detail.
Everyone is allowed to edit this compendium, if you see any errors feel free to correct them.
# GSM
The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-econd generation (2G) digital cellularstandard for mobile networks used b
In the early mobile1980s, a group was formed by the European Telecommunications Standards Institute (ETSI) to devices such as mobile phones and tabletselop a digital mobile communication system. Aptly named Groupe Speciale Mobile (GSM), its main task was to develop a single, consistent network for all of Europe and come up with a better and more efficient technical solution for wireless communication.
The GSM standard operates on three different carrier frequencies: the 900 MHz band, which was used by the original GSM system; the 1800 MHz band, which was added to support the swelling number of subscribers and the 1900 MHz frequency, which is used mainly in the U.S.
Although GSM is based on the time division multiple access (TDMA) system, its technology uses digital signaling and speech channels and is considered a second generation (2G) mobile phone system.
## Todahe Signalling Sy however the phstem Number 7
Signaling Sysical circuit switching has been virtualised and mantem No.7 (SS-7) is a telecommunications signaling architecture traditionally networused for the set up and tear down of telephone calls. It has a robust protocol stack nodes are connected over that uses out-of-band signaling to communicate between elements of the public switched telephone network (PSTN). In recent years it has been superseded by the Diameter signaling protocol on all-IP networks.
The SS-based broadband7 standard defines three basic types of network nodes:
- Service Switching Points (SSPs): responsible for establishing, transporting or forwarding connections.
- Service Control Points (SCPs): databases and application software that can influence call establishment.
- Signalling Transfer Points (STPs): responsible for the forwarding of signalling messages between SSPs and SCPs.
## Circuit-Switched Data Transmission
GSM was initally designed as a circuit switched network that establishes a direct and exclusive connection between two users on every interface between all network nodes of the system.