Presented by:Suresh Kumar MauryaELECTRONICS ENGG.B.TECH (7TH SEM)ROLL NO. 2811030004

INTRODUCTIONTelecommunication is the process of information transfer between the entities and an entity may be a computer,a human being and so on.Wireless telecommunication is type of telecommunication in which a information is transmitted through open space by electromagnetic wave.

Major ManufacturersNokiaMotorolaL.G.Sony EricssonSamsungVodafone

Cell SystemsCellular system is to provide personal telephone services to subscribers on the move.In this system a region is geographically divided into cell and the cells are hexagonal in shape. Each cell has a base station. Mobile terminals in a cell communicate via the base station of that cell.CELL STRUCTURE

Cellular Access Technologies

Frequency division multiple access (FDMA) Time division multiple access (TDMA) Code division multiple access (CDMA)

FDMA In an FDMA scheme , the radio frequency bandwidth is divided into adjacent frequency segments and each segment is provided with bandwidth to enable an associated communication.

FDMAFDMA puts each call on a separate frequency

TDMA TDMA is a technology used in digital cellular telephone that divides each cellular channel into time slot in order to increase the amount of data that can be carried.

TDMATDMA assigns each call a certain portion of time on a designated frequency

CDMACDMA is one of the major categorization of spread spectrum technology.CDMA allows many users to occupy the same time and frequency allocations in a given band.

CDMACDMA gives a unique code to each call and spreads it over the available frequencies.

Cells in the futurefourth-generation wireless phones may look more like hand held computers, with features such as video-conferencing, advanced personal calendar functions and multi-player gaming.

Another futuristic feature, will include making every day purchases through cellular communication with computer operated systems.

Problems with Cell PhonesCloningHazardous while drivingRadiation causing cancer

CLONINGIt is illegally duplicating of SIM indentification.In this process placing calls or using charge services using the account of cloned SIM.But at present it is more difficult to perform cloning.

HAZARDOUS WHILE DRIVINGIt is difficult to drive while talking on a cell phone.Most road accident occurs due to this.It is against the rule of driving.

RADIATION CAUSING CANCEREM radiation can directly reach to the cell phone .Cell phone is very near to our body parts which causes harmful radiation to reach our nerve system .It can be avoided upto a certain extent by using ear phone.