TABLE OF CONTENTS The earliest recorded instance of radio service to moving vehicles, such as ships, trains, and automobiles, was an experimental system in 1919 that provided two-way radio communication among coastal steamers between Boston and Baltimore [2], [3]. For the next 12 years or so, considerable improvement was made to radio communications technology to provide an effective high-seas mobile radio service. For land-based users, however, the earliest mobile phone service was in 1933, although research laboratories started experimenting with it much earlier. This system used a 35 MHz frequency band and was available only to police and fire departments. There were only 10 channels in the system with a 40 kHz spacing. It was a manual system where channel assignment and dialing were performed by the telephone operator. Because the mobile could not receive and transmit information simultaneously, the user had to "push to talk." There was no roaming feature available. In other words, users would receive service only in their registered home areas and would be denied the service if they moved to different serving areas.
Subsequently, in 1946, the FCC granted some spectrum on the 150 MHz band for an improved mobile telephone service; that year, following this spectrum allocation, the first commercial service was introduced in St. Louis, Missouri, and by the end of the same year, services were available to 25 other U.S. cities. These earlier systems were manual in that all calls were handled by a telephone operator. Because of the heavy demand for this...
