Multitransmitter digital signal transmission by using offset frequency strategy in a land-mobile telephone system

In a high-capacity land-mobile telephone system which employs a small zone technique, it is advantageous to provide control channels separate from voice channels. We first review two control channel allocation methods: the individual control zone system and the multiple control zone system. From the viewpoints of efficient frequency utilization and reliable call processing, the multiple control zone system is shown to be preferable. It is experimently verified that an offset carrier frequency strategy is well suited to the realization of this system. Simulation test results are presented which determine the design parameters. Offset carrier frequency allocation methods concerning three types of fundamental zone configuration are derived. The carrier frequency synchronization and the phase adjustment of the modulation signals are investigated for the actual system construction.