Method of assigning a voice/data channel as a temporary control channel in a radio communications system

In a central controller used in a radio communications system including a plurality of voice channels, the central controller allocating the voice channels to a plurality of subscribers using a first operational control channel, at least one of the voice channels being control-capable, the central controller including a database for storing subscribers information, which database includes records for the subscriber unit ID's along with a corresponding control channel ID, an improved method of sustaining a predetermined level of communications service to the plurality of subscribers in the system, the improved method comprising the steps of:

• evaluating a current loading condition for the first operational control channel;
• comparing said current loading condition with an upper loading threshold;
• receiving a registration request from a first of the plurality of subscribers on a request control channel;
• retrieving, from the database, a control channel identification (ID) associated with said requesting subscriber;
• enabling, responsive to said step of comparing, at least one of said control-capable voice channels as a temporary control channel to produce a second operational control channel for concurrent operation with the first operational control channel;
• determining whether said control channel ID matches an identification of the request control channel;
• and directing, responsive to the step of determining, the first subscriber to said control channel identified in the step of retrieving.

In a radio communications system having a first communication channel configuration, the system further having a central controller for allocating a plurality of voice channels to facilitate communication between radios in the system, the first configuration comprising a predetermined combination of voice channels and control channels, a method of providing a predetermined level of communications service to the radios, the method comprising the steps of:

• at the central controller;
• evaluating a current loading condition;
• determining whether the first communication channel configuration is capable of sustaining a level of communications service which is at least equal to the predetermined level;
• altering, responsive to said step of determining, the first communication channel configuration to produce a second communication channel configuration, wherein said second communication channel configuration includes an additional operational control channel for concurrent operation with those control channels established by the first communication channel configuration;
• identifying radios that are members of a common talk group to produce identified talk group radios;
• detecting whether at least one of the identified talk group radios is presently monitoring a control channel other than the additional operational control channel;
• and
• directing, responsive to the step of detecting, the at least one of the identified talk group radios to monitor the additional operational control channel;
• at the at least one of the identified talk group radios;
• monitoring, responsive to said step of directing, said additional operational control channel.