Advanced Mobile Phone Service (AMPS)

Advanced mobile phone service (AMPS) was the original analog cellular system in the United States. It is still in widespread use and in 1997, AMPS systems were operating in over 72 countries [ ^[3]]. The AMPS system continues to evolve to allow advanced features such as increased standby time, narrowband radio channels, and anti-fraud authentication procedures.

In 1974, 40 MHz of spectrum was allocated for cellular service [ ^[4]] which provided only 666 channels. In 1986, an additional 10 MHz of spectrum was added to facilitate expansion [ ^[5]] of the system to 832 channels.

The frequency bands for the AMPS system are 824 MHz to 849 MHz (uplink) and 869 MHz to 894 MHz (downlink). Of the 832 channels, AMPS systems are divided into A and B bands to allow for two different service providers. There are two types of radio channels in an AMPS system; dedicated control channels and voice channels. On each system (A or B), mobile telephones scan and tune to one of 21 dedicated control channels to listen for pages and compete for access to the system. The control channel continuously sends system identification information and access control information. Although the control channel data rate is 10 kbps, messages are repeated...