METHOD AND APPARATUS FOR ASSIGNING DUPLEX RADIO CHANNELS AND SCANNING DUPLEX RADIO CHANNELS ASSIGNED TO MOBILE AND PORTABLE RADIOTELEPHONES IN A CELLULAR RADIOTELEPHONE COMMUNICATIONS SYSTEM

摘要

A unique method and apparatus for efficiently assigning duplex radio channels and scanning duplex radio channels assigned to mobile and portable radiotelephones in a cellular communications system (Fig. 1). Each cell (10, 20, 30) includes a base station radio (111, 121, 131) having a signalling channel and a plurality of voice channels, and a base site controller (112, 122, 132) adapted to utilize the methods embodying the present invention for controlling communications paths to mobile and portable radiotelephones. The base station radios (Fig. 2) include a signalling transceiver (250) operable on the signalling channel, a plurality of voice transceivers (220, 230) each operable on a voice channel, and a scanning receiver (240) for sampling the signal strength of active radiotelephones. Transmitters of the signalling transceivers (250) and voice transceivers (220, 230) are combined (210) and coupled to an omnidirectional antenna (212); and the receivers of the signalling transceiver (250), voice transceivers (220, 230) and scanning receiver (240) are coupable to one or more of six sector antennas (214). In practicing the methods of the present invention, the microprocessor (358) controlled base site controller maintains high quality communications paths to mobile and portable radiotelephones by periodically monitoring their signal strength and when signal strength degradations are detected, either changing the base station sector antennas (214) coupled to voice transceivers (220, 230), increasing or decreasing radiotelephone power output, or handing radiotelephones off to another cell.