Page 202 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

MODULE 13 : Cell phones

LESSON 118 - 126 : Cell Phones

Objectives

At the end of this lesson you shall be able to
• explain basic concepts involved in cellular system
• explain various aspects involved in cellular communication.

Mobile Communication is the use of technology that allows us to communicate with others in different locations
without the use of any physical connection (wires or cables). Mobile communication makes our life easier, and
it saves time and effort. In mobile communications, high-frequency electromagnetic fields are used for wireless
transmission of voice and data. In free space they propagate as waves at the speed of light while being able to
transmit energy and information over long distances.
History of Wireless Communication
The history of the wireless communications started with the understanding of magnetic and electric properties
observed during the early days by the Chinese, Roman and Greek cultures and experiments carried out in the
17th and 18th centuries. A short history of wireless communication is presented in the tabular form:

Year Description
1880 Hertz-Radio Communication
1897 Marconi- Radio Transmission

1933 FCC (Federal Communication Commission)
1938 FCC rules for regular services
1946 Bell telephone laboratories 52 MHz
1956 FCC - 450MHz (Simplex)
1964 Bell telephone active research 800 MHz
1964 FCC - 450 MHz (Full Duplex)
1969 FCC - 40 MHz bandwidth
1981 FCC? release of cellular land phone in the 40 MHz

1982 At & T divested and Server RBOC (Regional Bell Operation Companies) formed to manage the
cellular operation.
1984 Most RBOC market in operations
1986 FCC allocates 5MHz extended band.
1988 TDMA was voted as digital cellular standard in North America.
1992 GSM (Group Special Mobile) operable Germany D2 system.
1993 CDMA (Code Division Multiple Access)
1994 PDCC (Personal Digital Cellular Operable) in Tokyo, Japan

1995 CDMA operable in Hong Kong
1996 Six Broad Band PCS (Personal Communication Services) licensed bands (120 MHz) almost
reader 20 billion US dollar
1997 Broad band CDMA constructed and of the 3rd generation mobile.
1999 Powerful WLAN systems were evolved, such as Bluetooth. This uses a 2.4 MHz spectrum.

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