First Generation (1G)

Although the advancement of technology (any technology) certainly involves
quantum leaps forward from time to time, it is common for major progress
to also occur as a result of incremental improvements. For mobile communications
technology, advancement has come about in both ways—through
occasional revolution and almost certain evolution. Therefore, although the
book deals primarily with the technology of third-generation (3G) wireless
networks, an understanding of earlier systems is important. This understanding
provides the appropriate perspective from which to view 3G systems
and helps us understand how solutions for 3G systems have been
developed. In other words, it is easier to understand where we are going if
we understand where we have been. To help in that understanding, this
chapter provides an overview of first-generation (1G) systems.
Cellular communication, referred to as 1G, is one of the most prolific
voice communication platforms that has been deployed within the last
two decades. Overall, cellular communication is the form of wireless communication
that enables several key concepts to be employed, such as the
following:

■ Frequency reuse
■ Mobility of the subscriber
■ Handoffs

The cellular concept is employed in many different forms. Typically, when
referencing cellular communication, it is usually associated with either the
Advanced Mobile Phone System (AMPS) or Total Access Communication
Services (TACS) technology. AMPS, operates in the 800-MHz band (821 to
849 MHz) for base station receiving and (869 to 894 MHz) for base station
transmitting. For TACS, the frequency range is 890 MHz to 915 MHz for
base receiving and 935 MHz to 960 MHz for base station transmitting.
Many other technologies also fall within the category of cellular communication
and those involve the Personal Communications Service (PCS)
bands, including both the domestic U.S. and international bands. In addition,
the same concept is applied to several technology platforms that are
currently used in the specialized mobile radio (SMR) band (IS-136 and
iDEN). However, cellular communication is really utilized by both the
AMPS and TACS bands but is sometimes interchanged with the PCS and
SMR bands because of the similarities. However, AMPS and TACS systems
are an analog-based system and not a digital system.

The concept of cellular radio was initially developed by AT&T at their
Bell Laboratories to provide additional radio capacity for a geographic customer
service area. The initial mobile systems that cellular evolved from
were called mobile telephone systems (MTSs). Later improvements to these
systems occurred and the systems were referred to as improved mobile telephone
systems (IMTSs). One of the main problems with these systems was
that a mobile call could not be transferred from one radio station to another
without loss of communication. This problem was resolved by implementing
the concepts of reusing the allocated frequencies of the system. Reusing the
frequencies in cellular systems enables a market to offer higher radio traffic
capacity. The increased radio traffic enables more users in a geographic
service area than with the MTS or IMTS systems.
Cellular radio was a logical progression in the quest to provide additional
radio capacity for a geographic area. The cellular system, as it is known
today, has its primary roots in the MTS and the IMTS. Both MTS and IMTS
are similar to cellular with the exception that no handoff takes place with
these networks.

Cellular systems operate on the principal of frequency reuse. Frequency
reuse in a cellular market enables a cellular operator the ability to offer
higher radio traffic capacity. The higher radio traffic capacity enables many
more users in a geographic area to utilize radio communication than are
available with a MTS or IMTS system.

The cellular systems in the United States are broken into the Metropolitan
Statistical Area (MSA) and Rural Statistical Areas (RSAs). Each MSA
and RSA have two different cellular operations that offer service. The two
cellular operations are referred to as A-band and B-band systems. The Aband
system is the non-wireline system and the B-band is the wireline system
for the MSA or RSA.