Basic GSM Configuration

A basic GSM configuration is shown.
It consists of the basic system blocks of the GSM network namely the MSC (Mobile Switching Center), TRAU (TRANSCODER), BSC (Base System Controller, BTS ( Base Transceiver Station) and MS (Mobile Station).
In Figure above, the mobile station talks with the BTS through the use of full duplex radio transmissions using a separate transmit and receive frequency to communicate with each other.
The BTS transmits on the frequency the mobile is tuned to and the mobile transmits to the frequency the BTS receiver is tuned to. The BTS in a system connect to the BSC through a transmission system. It can be one of these: Terrestrial transmission, Fiber Optic Transmission, Satellite Transmission, Leased line Transmission, etc. From BSC , the connection is going to TRAU (Trans-coder), and converting or adapting the bit rates from 16 kbps to 64 kbps (PCM-Standard) , and the end of connection is MSC.
The MS is a radiotelephone that may be used whenever "cell" coverage is provided. The term "mobile phone" has been used generically to include several forms of wireless communication. This term represents fully portable cellular and digital phones in addition to hand-held and hands-free car phones.
The BTS is a transceiver facility that provides the cell coverage. The cell provided by a cell site can be from one mile to twenty miles in diameter, depending on terrain and transmission power. Several coordinated cell sites are called a cellular network.
The BSC is the controller of BTS and manage the group of BTS for doing something like handover, radio resources management.
The TRAU is a unit which has function to convert the bit rate from 16 kbps (GSM bit rates Full rate) to 64 kbps (PCM Standard).
The MSC is the switching parts. These systems is doing the function like allocate the traffic channel, arranges handoffs, call routing, keeps track of billing information, etc.

Types of Telecommunication Networks

In its most basic form a network is an interconnected system of things or people. From a technical standpoint a network is a data communication system that interconnects computer systems at different sites, or the connection of two or more computers using a communications system.

Most networks can be classified into one of five different types. These include wide area networks (WAN), local area networks, (LAN), virtual private networks (VPN), client/server networks, network computing, and peer-to-peer networks.

Wide Area Network (WAN)

Any network that encompasses a large geographic area is referred to as a WAN. Many large businesses and government agencies use WANs to keep their employees and citizens connected as well as provide a quick and effective way to send and receive information.

Metropolitan Area Network (MAN)

A MAN is a network that covers a region, often a metropolitan area that is bigger than a Local Area Network and smaller than a Wide Area Network and consists of several interconnected LANs. This network often serves regional businesses that have several locations throughout the region or entire cities. With this configuration, a MAN often is then connected to larger WAN networks.

There are three features that differentiate MANs from LANs or WANs:

1. The area of the network size is between LANs and WANs. The MAN will have a physical area between 5 and 50 km in diameter.

2. MANs do not generally belong to a single organization. The equipment that interconnects the network, the links, and the MAN itself are often owned by an association or a network provider that provides or leases the service to others.

3. A MAN is a means for sharing resources at high speeds within the network. It often provides connections to WAN networks for access to resources outside the scope of the MAN.

Campus Area Network (CAN)

A CAN is a network that is restricted to a small geographic area such as a building complex or a college campus. It is smaller than a Metropolitan Area Network but larger than a Local Area Network. The CAN incorporates several LANs and usually has connections to a MAN or WAN.

Local Area Network (LAN)

Similar in many ways to WANs; LANs are responsible for connecting computers in a much smaller limited physical area. A good example of a LAN would be a hotel's wireless Internet offering which is self-contained within their own facility.

There are multiple standards for Local Area Networks. Examples include IEEE 802.3 (Ethernet), IEEE 802.11 (Wi-Fi) or ITU-T G.hn (using existing home wires, such as power lines, phone lines and coaxial cable).

Personal Area Network (PAN)

A Personal Area Network (PAN) is a network that is restricted to the area of a person's body. It is much smaller than Local Area Network. It typically incorporates ad hoc connections to other PANs or directly to BlueTooth devices.

Virtual Private Network (VPN)

VPNs are a type of network that builds on the concept of a WAN however relies upon the internet and an encrypted connection mechanism to establish a secure environment for internal or external employees or customers.

Client/Server Network

The Client Server network architecture continues to be the main architectural choice for most enterprise network computing. In a client/server environment the client (i.e. PC) relies on a LAN to connect with a back office network server that is responsible for the connection, retrieval, and storage of data and other critical company or personal information.

Network Computing

Network Computing is a network architecture that has grown with the Internet and resulting connection speeds. In a network computing architecture a computer uses its web browser to connect to another network computer that actually is running the application. A good example of this architecture in use is Google Docs, or Microsoft Office online. Both services allow users the ability to login to Google or Microsoft servers respectively and work similarly to how it would be performed on their own computing environment.

Peer-to-Peer Network

Peer to peer networks are now beginning to be realized for the positive benefits they provide and not as only used for the sharing of copyrighted material. Peer-to-peer networks can be separated into two major types: Central Server and Pure.

In a central server environment one host server maintains all active connections and shared information. When information is requested the central server informs the user where they can receive the file and allows the connection directly to the other PC to download.

A pure peer-to-peer network type has no central server to maintain active users relies instead on the individual computers to seek out all other computers offering the same information being requested. A good example of this type would be BitTorrent software which allows small parts of information to be pulled from many sources which once completed compiles into the one file that is being downloaded.