System and method for an underlay cellular system

摘要

An underlay cellular telephone system disposed within a main cellular telephone system is provided. Specifically, the invention includes a system and method suitable to provide an independent cellular system which operates as an underlay system to an existing main cellular system and provides public or private cellular service without the need for system returning or frequency coordination with the main cellular system. The main cellular system includes a plurality of contiguous cells, each of said cells having a fixed set of frequencies (or "channels") and a main controller (also referred to as a "switch" or "MSC") operatively coupled to said cells for coordination and control of communication within the main cellular system. The underlay cellular system operates to determine which of the fixed set of frequencies are under-utilized and establishes communication over any number of the under-utilized frequencies without coordination and control by the main controller. The underlay cellular system monitors the continued availability of the under-utilized frequencies by detecting certain interference conditions, and updates the under-utilized frequencies.