Telecomunication And Networking

Terms of Reference

Wireless communication is one of the most vibrant areas in the communication field today. While it has been a topic of study since the 1960s, the past decades has seen a surge of research activities in the area. This is due to a confluence of several factors.

First, there has been an explosive increase in demand for tetherless connectivity, driven so far mainly by cellular telephony but expected to be soon eclipsed by wireless data application.

TASK:

Describe and discuss the characteristics of cellular networks and wireless data application.

Introduction.

Basically this is an assigning title Telecommunication and networking we were task to give more details of what we no or to make more research about cellular networking and wireless data application .This tasks was given to us by S Derricks' and was meant to be submit by the 3rd of December 2007 .

Firstly, I went on to first explain what a cellular network is then give some examples of it component like the GSM, 3G, 4G(futures), 5G(futures). Proceeding, I talked about the wireless data application, give a example of a mobile phone, the functions of the cellular network application e.g. text, browse, msm, wasp, gprs, etc.

Then I went to my conclusion which was really brief. I thing you will enjoy as you go along this task thanks.

Main Body

What is a Cellular Network?

A cellular network allows cellular subscribers to wander anywhere in the country and remain connected to the Public Switched Telephone Network (PSTN) via their mobile phone. A cellular network has a hierarchical structure and it is formed by connecting the major components mentioned below:-

. Mobile phone Ð'- main piece of equipment as far as a subscriber is connected

. Base Station (BS)

. Mobile Switching Centre (MSC)

Base Station (BS)

The base station serves a cell which could be a few kilometres in diameter as shown in the diagram above.

Cellular networks are inherently asymmetric with a set of fixed main transceivers each serving a cell and a set of distributed (generally, but not always, mobile) transceivers which provide services to the network's users.

Cellular networks offer a number of advantages over alternative solutions:

Ð'* increased capacity

Ð'* reduced power usage

Ð'* better coverage

Cellular Telephony

The most common example of a cellular network is a mobile phone (cell phone) network. A mobile phone is a portable telephone which receives or makes calls through a cell site (base station), or transmitting tower. Radio waves are used to transfer signals to and from the cell phone. Large geographic areas (representing the coverage range of a service provider) are split up into smaller cells to deal with line-of-sight signal loss and the large number of active phones in an area. In cities, each cell site has a range of up to approximately Ð'Ð... mile, while in rural areas, the range is approximately 5 miles. Many times in clear open areas, a user may receive signal from a cell 25 miles away. Each cell overlaps other cell sites. All of the cell sites are connected to cellular telephone exchanges "switches", which in turn connect to the public telephone network or another switch of the cellular company.

As the phone user moves from one cell area to another, the switch automatically commands the handset and a cell site with a stronger signal (reported by the handset) to go to a new radio channel (frequency). When the handset responds through the new cell site, the exchange switches the connection to the new cell site. Handsets share a specific radio channel with CDMA, multiple CDMA: The signals are separated by using a pseudonoise code (PN code) specific to each phone. It affect if the user moves from one cell to another, the handset sets up radio links with multiple cell sites (or sectors of the same site) simultaneously. This is known as "soft handoff" because, unlike with traditional cellular technology, there is no defined point where the phone switches to the new cell.

Basically Modern mobile phones use cells because radio frequencies are a limited, shared resource. Cell-sites and handsets change frequency under computer control and use low power transmitters so that a limited number of radio frequencies can be reused by many callers with less interference. CDMA handsets, in particular, must have strict power controls to avoid interference with each other. An incidental benefit is that the batteries in the handsets need less power.

Some another examples of cellular technology is the GSM, WAP, GPRS, 2G, 3G, 4G,

GSM

GSM means Global System for Mobile Communication, one of the leading digital cellular systems. GSM was first introduce in 1991, as of the end of 1997, GSM service was available in more than 100 countries and has become the do facto standard in Europe, Asia and Africa. Mobile phones are connected to it by searching for cells in the immediate vicinity GSM networks operate in four different frequency ranges. Most GSM networks operate in the 900 MHz or 1800 MHz bands. Some countries in the Americas (including Canada and the United States) use the 850 MHz and 1900 MHz bands because the 900 and 1800 MHz frequency bands were already allocated. GSM network uses four different cell size and which are, macro, micro, Pico and umbrella cells. The coverage area of each cell varies according to the implementation environment. Macro cells can be regarded as cells where the base stations antenna is installed on a mast or a