The history of mobile communication can be traced back to the early 20th century, but its fast growth did not come until recent 20 years. The development of mobile communications technologies is basically focused on opening new frequency ranges for mobile communications, effective frequency utilization, and mobile station miniaturization and portability. Here, the technology for effective frequency utilization is the core of mobile communications.
The first mobile telephone system was commissioned in the United States in 1940’s. Bell Labs in the United States introduced the concepts and theory of cellular systems in the early 1970’s. The evolution of cellular mobile communication systems is shown in TABLE 1.
AMPS： Advanced Mobile Phone System
TACS： Total Access Communication System
GPRS： General Packet Radio Services
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