Radio telephone system with one-to-many dispatch system

• US 6,714,795 B1
• Filed: 06/26/2000
• Issued: 03/30/2004
• Est. Priority Date: 06/26/2000
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Retzer, Michael H., Ladhani, Nuruddin, Long, Earle G.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): D AGOSTA, STEPHEN M
• Application Number:
  US09/603,099
• Time in Patent Office: 1,373 Days
• Field of Search: 455/515, 455/516, 455/518, 455/519, 455/520, 455/521, 455/414.1, 455/416, 370/328, 370/329, 370/337
• US Class Current: 455/518
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services

Abstract

A one-to-many dispatch method for use in a TDMA or other wireless telephone system. The one-to-many dispatch call is placed by sending a Request message 204 from a Personal Station PS 112 to a Control Center Station (CS) 120 which assigns a channel with an Assignment message 208. The PS 112 sends a call setup message over the control channel resulting in a channel assign message 242 being broadcast repeatedly. Call connect messages over the Assigned Channel AC 244 are also repeated from the CS 120 to indicate the open connection. A hang timer is started when the PS 112 ceases transmission of voice and the connection is torn down upon expiry of the hang timer unless another PS transmits a call setup message 234 on the Assigned Channel AC before the expiry of the hang timer.

Claims

1. A method of carrying out a one-to-many Dispatch call among members of a talkgroup on a telephone system, comprising:

over a Control Channel, establishing an Assigned Communication Channel for sending a call setup message from a personal station having a personal station ID to a Control Station, using a Request message containing a talkgroup ID for the talkgroup;

sending gather messages containing the talkgroup ID on a common Paging Channel PC;

sending connect messages containing the first personal station ID on the Assigned Communication Channel indicating to the first personal station the right to transmit information on the communications channel;

transmitting information from the first personal station on the Assigned Communication Channel;

detecting a signal loss in the transmitted information; and

initiating a dropout timer.

2. The method in accordance with claim 1, further comprising:

transmitting connect messages containing the first personal station ID on the Assigned Communication Channel for a duration of the dropout timer.

3. The method in accordance with claim 1, further comprising:

transmitting release messages over the Assigned Communication Channel after the duration of the dropout timer expires.

4. The method in accordance with claim 2, further comprising:

receiving an information transmission from the first personal station during said dropout timer; and

stopping the dropout timer in response to receiving the information transmission.