Dispatch communication system with adjacent system signal repeating

• US 5,369,781 A
• Filed: 02/06/1992
• Issued: 11/29/1994
• Est. Priority Date: 12/27/1989
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Sobti, Arun, Comroe, Richard
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): FAILE, ANDREW I
• Application Number:
  US07/832,137
• Time in Patent Office: 1,027 Days
• Field of Search: 455/11.1, 455/15-16, 455/34.1, 455/34.2, 455/33.1, 455/54.1, 455/56.1, 455/54.2, 455/17, 455/20
• US Class Current: 455/15
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A dispatch communication system wherein a communication unit may move from the service coverage area of a first system to the service coverage area of a second system during a communication transaction without the need to re-initiate the call. Communication units and base sites under this invention are constructed to relay signals to and from the system where the call originated.

Claims

1. An apparatus for relaying signals between a first and second dispatch communication system with each communication system of the first and second communication system having a plurality of communication units that transmit and receive signals using a predetermined format and a service coverage area with a periphery, wherein at least the first communication system includes the apparatus for relaying signals comprising:

A) a plurality of communication resources configured to communicate with at least some of the plurality of communication units of the first and second communication systems;

B) at least one communication control resource;

C) at least one communication resource configured to transmit and receive signals in the format; and

wherein at least one of the plurality of communication units is transmitting and receiving a communicated signal through the second communication system, said at least one communication unit including scanning means for detecting the at least one control resource of the first communication system and control means for requesting, when near the periphery of the service coverage area of the second communication system and over the at least one control resource, that the first communication system allocate communication resources to relay the communicated signal to and from the second communication system.

2. The communication system as recited in claim 1, wherein the at least one communication unit transmitting and receiving a communicated signal monitors the communicated signal signal strength of said second communication system and when the signal strength exceeds a threshold requests additional communication resources from said first communication system.

3. A method of assigning communication resources to communication units in a first communication system and a second communication system, the communication systems having:

A) a plurality of communication resources;

B) a service coverage area for each communication system;

C) a communication unit near the periphery of the service coverage area of the second communication system and entering the service coverage area of the first communication system, transmitting and receiving a signal through the second communication system;

and wherein the communication unit includes scanning means for detecting control frequencies of the first communication system, and wherein the communication unit includes control means for requesting over a control resource that the first communication system allocate communication resources to relay the signal to and from the second communication system, the method comprising the steps of;

A) monitoring by the communication systems the receive control resource for requests for communication resources from the communication unit;

B) receiving at the first communication system a request for communication resources from the communication unit, such request containing the ID of the communication unit, the ID of the second base site, and the frequency used by the communication unit in transmitting and receiving the signal with the second communication system;

C) allocating by the first communication system a communication resource between the communication unit and the first communication system;

D) allocating by the first communication system a transmit and receive resource between the first communication system and the second communication system; and

,

E) allocating by the first communication system a signal path between the communication unit and the second communication system.

4. The method of assigning communication resources in claim 3, wherein the communication unit monitors the communicated signal strength of said second communication system transmit resource and when the signal strength exceeds a threshold requests additional communication resources from said first communication system.