Basics of Wireless
Network
The first commercially available radio ang telephone system,
knows as the Improved Mobile Telephone Service ( IMTS ), was put into service
in 1946. In order to use IMTS, a tall transmitter tower was erected near the center
of a metropolitan area. Given these constrictions, the number of
channels available did not come close to satisfying the demand.
The solution to this problem was cellular radio.
Metropolitan areas were divided into cells of no more than a few miles in
diameter, each cell operating on a set of frequencies ( sending ang receiving )
that divered from the frequencies of the adjacent cells.
The first is their controlled handoff. Second, systems were
designed to locate particular subscribers by paging them in each of the cells.
The initial transmission technology used between the vehicle
and the cell site was analog in nature and known as Advanced Mobile Phone
System ( AMPS ). The analog scheme used was called frequency – division
multiple access ( FDMA ).
Communications
between the cell site and the switch utilize transmission media such as
microwave, copper pairs, and fiber optics.
The continuing growth of cellular communications led government and industry in
the United States to search for additional ways to satisfy the obvious need not
only for ordinary telephone service but also for special services and features,
smaller telephones, and cellular phone us.
Additional frequency bands were allocated for their use,
rather than assign them to the first comers or by way of a lottery the Federal
Communication ( FCC ) [1] auctioned them off throught a sophisticated bidding
contest that brought the U.S Treasury billions of dollars.
