INTRODUCTION A type of wireless communication that is most familiar to mobile phones users. It's called 'cellular' because the system uses many base stations to divide a service area into multiple 'cells'. Cellular calls are transferred from base station to base station as a user travels from cell to cell. -
DEFINITION A mobile phone is a device which behaves as a normal telephone whilst being able to move over a wide area ( cf. cordless phone which acts as a telephone only within a limited range). Mobile phones allow connections to be made to the telephone network , normally by directly dialing the other party's number on an inbuilt keypad. Most current mobile phones use a combination of radio wave transmission and conventional telephone circuit switching , though packet switching is already in use for some parts of the mobile phone network, especially for services such as internet access and WAP .
HISTORY The basic concept of cellular phones began in 1947, when researchers looked at crude mobile (car) phones and realized that by using small cells (range of service area) with frequency reuse they could increase the traffic capacity of mobile phones substantially. However at that time, the technology to do so was nonexistent. Anything to do with broadcasting and sending a radio or television message out over the airwaves comes under Federal Communications Commission (FCC) regulation
cell phone is a type of two-way radio. In 1947, AT&T proposed that the FCC allocate a large number of radio-spectrum frequencies so that widespread mobile telephone service would become feasible and AT&T would have a incentive to research the new technology. We can partially blame the FCC for the gap between the initial concept of cellular service and its availability to the public. The FCC decided to limit the amount of frequencies available in 1947, the limits made only twenty-three phone conversations possible simultaneously in the same service area - not a market incentive for research. HISTORY
HISTORY The FCC reconsidered its position in 1968, stating "if the technology to build a better mobile service works, we will increase the frequencies allocation, freeing the airwaves for more mobile phones." AT&T and Bell Labs proposed a cellular system to the FCC of many small, low-powered, broadcast towers, each covering a 'cell' a few miles in radius and collectively covering a larger area. Each tower would use only a few of the total frequencies allocated to the system. As the phones traveled across the area, calls would be passed from tower to tower.
Advantages of cellular phone <ul><li>They enable us to communicate business; science or any other data to places anywhere in the world This promotes business and science on the basis of latest information and knowledge. </li></ul><ul><li>The mobile phone technology has made possible exploration of distant places in nature or dangerous areas. </li></ul>
Advantages of cellular phone <ul><li>Instead of having hotlines or regular telephone links; the rulers or leaders of different can have cellular links all the time. </li></ul><ul><li>As a protection against criminals or terrorist; the mobile phone can prove to be very effective. </li></ul> close window
Advantages of cellular phone <ul><li>The mobile phone is profitably used by businessmen touring distant parts of their country and foreign countries. </li></ul><ul><li>The money exchange of different countries make free use of mobile phone in their business activities. </li></ul>
Disadvantages of cellular phones <ul><li>Several hijackings of planes have been carried out by criminals with mobile phones informing each other and by sending wrong to control towers about the directions and movements of the planes. </li></ul><ul><li>A constant use of mobile phone causes tumours(swellings) in the brain. </li></ul><ul><li>The mobile phone is; in fact; a double-edged weapon.Criminals and terrorists make use of this device to keep contact with each other. </li></ul>
Disadvantages of cellular phones <ul><li>Complete dependence on it on the part of its users for their daily work and business dealings can result in a kind of mechanical life in which physical or mental effort is excluded. </li></ul><ul><li>Because of their constant use; a few of them become nervous or confused.In some; loss of memory has been reported. </li></ul>
Disadvantages of cellular phones <ul><li>Competition among mobile companies promotes negative uses of the device.Through advertisements and convassing(asking people for its use); they make people waste time and spend more on mobile talks than on books and learning . </li></ul>