Two-way radio communication system with max-minimum call assignment method

Control apparatus for a trunking communication system having a single centrally located control station for providing service via a limited number of channels to a plurality of subscribers, the apparatus comprising:

• subscriber stations having:
• (a) means for requesting a channel assignment from the central control station;
• (b) means responsive to an assigned channel signal to operate on said channel with variable power output and measure inbound and outbound link quality;
• (c) means for generating an end of information interchange signal at the conclusion thereof;
• and
• the central control station having:
• (a) means for determining a present channel, including means for identifying subscribers and means for establishing a minimum quality factor on each channel so as to establish at least one eligible channel for a requesting subscriber;
• (b) means for supervising channel activity comprising:
• means for comparing the present minimum quality factor for each channel with respect to other channels so as to establish eligible channels;
• means for assigning a requesting subscriber to any of said eligible channels which is above a given threshold value;
• means for controlling the power output of said subscribers;
• and
• (c) means for detecting an end of transmission or end of message signal from any subscriber and truncating the channel assignment in response thereto.

In a communications trunking system having a single central controller and a plurality of identifiable subscriber radios, the central controller routing interchanged traffic between subscriber radios over a limited number of identify information channels, and control occuring on a control channel, each identifiable subscriber radio comprising:

• controllably tuned transceiver means for communication via a control channel or an assigned information channel to the central controller;
• control means within said subscriber radio for requesting a channel assignment, for providing a measure of part of an outbound link quality as communications link quality between the central controller and said radio, and responsive to an assigned channel signal from the central controller to operate on a given channel;
• and
• transceiver power output controlling means, coupled to said transceiver, for receiving a power output control signal from the central controller for changing power output on the asigned channel and response thereto.

A method for assigning a channel to a requestor in addition to serving a plurality of present subscribers operating on a radio system having a limited number of channels, the method comprising the steps of:

• (a) monitoring at least some of the channels;
• (b) identifying a weakest subscriber in at least some of the monitored channels;
• (c) comparing at least some of said weakest subscribers to one another according to a first predetermined criteria to determine a first subgroup of said weakest subscribers;
• (d) selecting channels associated with said first subgroup of said weakest subscribers according to a second predetermined criteria to derive a second subgroup of said weakest subscribers;
• (e) identifying at least one channel from said second subgroup that may be assigned to the requestor with minimal interference on the present subscribers operating on said system;
• (f) assigning one of said identified channels to said requestor.