Trunked communication system with nationwide roaming capability

A network of trunked communication systems constructed and arranged to support subscriber units roaming from system to system, comprising:

• a central computer for communicating with at least two trunked communication systems;
• said at least one trunked communication system, each comprising:
• a plurality of trunked repeaters;
• central control means for allocating said plurality of trunked repeaters among a plurality of subscriber units, and for communicating information with at least some of said plurality of subscriber units on a selected one of said plurality of trunked repeaters, and including means for transmitting a predetermined code word on said selected one of said plurality of trunked repeaters;
• means for communicating with said central computer and for assigning identification codes to roaming subscriber units;
• means for interfacing with a telephone network;
• and
• said plurality of subscriber units, at least some of which have:
• means for communicating with said central control means of each of said at least two trunked communication systems over said selected one of said plurality of trunked repeaters regardless of whether said selected one of said selected plurality of trunked repeaters used by each of said central control means of said at least two trunked communication systems has a different communication frequency;
• means for determining that communication with said central control means of one of said at least two trunked communication systems is not possible;
• and
• means for requesting an identification code from a central control means from another of said at least two trunked communication systems.

In a network of trunked communication systems constructed and arranged to support subscriber units roaming from system to system and having a central computer for communicating with at least two trunked communication systems, and each of the at least two trunked communication systems having:

• a plurality of trunked repeaters;
• central control means for allocating said plurality of trunked repeaters among a plurality of subscriber units, and for communicating information with at least some of said plurality of subscriber units on a selected one of said plurality of trunked repeaters, and including means for transmitting a predetermined code word on said selected one of said plurality of trunked repeaters;
• means for communicating with said central computer and for assigning identification codes to roaming subscriber units;
• and
• means for interfacing with a telephone network,
• a method for establishing an interconnect call with a subscriber unit operating in any of the at least two trunked communication systems, comprising the steps of:
• (a) contacting said central computer;
• (b) transmitting at least a unit identification of a subscriber unit to said central computer;
• (c) receiving an information signal representing a public telephone number associated with the particular trunked communication system that the subscriber unit having said unit identification is operating in;
• (d) accessing said particular trunked communication system via said telephone network;
• (e) transmitting said unit identification of said subscriber unit to said particular trunked communication system;
• (f) communicating with said subscriber unit after said particular trunked communication system determines the identification code currently assigned to said unit identification and establishes a wireless communication channel.

In a network of trunked communication systems constructed and arranged to support subscriber units roaming from system to system and having a central computer for communicating with at least two trunked communication systems, wherein each of the at least two trunked communication systems comprises:

• a plurality of trunked repeaters;
• central control means for allocating said plurality of trunked repeaters among a plurality of subscriber units, and for communicating information with at least some of said plurality of subscriber units on a selected one of said plurality of trunked repeaters, and including means for transmitting a predetermined code word on said selected one of said plurality of trunked repeaters which represents that roaming subscriber units may communicate with said central control means to operate within the particular trunked communication system associated with said central control means;
• means for communicating with said central computer and for assigning identification codes to roaming subscriber units;
• and
• means for interfacing with a telephone network.

In a network of trunked communication systems constructed and arranged to support subscriber units roaming from system to system and having a central computer for communicating with at least two trunked communication systems, and each of the at least two trunked communication systems having:

• a plurality of trunked repeaters;
• central control means for allocating said plurality of trunked repeaters among a plurality of subscriber units, and for communicating information with at least some of said plurality of subscriber units on a selected one of said plurality of trunked repeaters;
• means for communicating with said central computer and for assigning identification codes to roaming subscriber units;
• and
• means for interfacing with a telephone network,
• a signalling method for supporting roaming subscriber units, comprising the steps of:
• (a) transmitting a predetermined code on said selected one of said plurality of trunked repeaters, which may be used to identify roaming support capability;
• (b) receiving a roaming request code from a subscriber unit;
• (c) assigning a roaming identification code to said subscriber unit;
• (d) transmitting said roaming identification code to said subscriber unit.