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Wireless communications is growing at a phenomenal rate. From 1991 to
1999, the number of subscribers increased from about 25 million to over 250
million. Incredibly, over the next seven years, the number. of subscribers is
expected to quadruple, to over 1 billion [ 1]. That growth rate is faster than
that of any other consumer electronics product and is similar to that of the
Internet.
Originally, wireless communications were motivated by and intended for
mobile voice services. Later on, the first analog systems were improved with
digital techniques, providing increased robustness and subscriber capacity. In
the near future, digital systems will be augmented to try to meet users’ insatiable
need for even greater capacity and high-speed mobile data services.
Wireless communications rely on multiple-access techniques to share
limited radio spectrum resources. These techniques, which use frequency, time,
and power to divide the precious radio spectrum, are described in standards
and are highly regulated. As such, infrastructure and subscriber manufacturers
can be different and interchangeable.
This book details the complete operation of a mobile phone. It describes
code division multiple access (CDMA) design issues but presents concepts and
principles that are applicable to any standard. The book emphasizes CDMA
because next-generation standards are based on that multiple-access technology.
This book uniquely ties together all the different concepts that form the
mobile radio. Each of these concepts, in its own right, is suitable material for
a book, if not several books, but is presented in such a way as to highlight
key design issues and to emphasize the connection to other parts of the mobile
radio. |
