System and method for interrupting a transmitting communication unit in a communication system

• US 8,144,846 B2
• Filed: 01/08/2007
• Issued: 03/27/2012
• Est. Priority Date: 01/08/2007
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Gilbert, John M., Hunsberger, Gary P., McDonald, Daniel J.
• Primary Examiner(s): Anwah, Olisa
• Application Number:
  US11/620,776
• Publication Number:
  US 20080167062A1
• Time in Patent Office: 1,905 Days
• Field of Search: 455/518, 455/90.2, 455/78, 455/88, 455/450, 455/509, 379/93.01, 379/93.02, 379/93.04, 379/93.08
• US Class Current: 379/93.02
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 76/30 Connection release
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services

Abstract

A system and method for interrupting a transmitting communication unit in a communication system. When a call is first initiated, the call is assigned to a communication channel and broadcast from a base site using the assigned communication channel. If it is determined that a transmitting communication unit should be interrupted, a zone controller signals a base site to generate an interrupt message. The base site generates an interrupt message containing an identification code for the transmitting communication unit and broadcasts the interrupt message on an outbound link of the communication channel. The transmitting communication unit, while transmitting on an inbound link of the communication channel, continuously monitors the outbound link. If the transmitting communication unit receives, on the outbound link, an interrupt message containing an identification code matching its own identification code, the transmitting communication unit stops transmitting.

Claims

1. A method for interrupting a communication unit transmitting a call in a communication system, the method comprising:

assigning the call to a communication channel;

receiving the call from the communication unit on an inbound link of the communication channel;

determining whether the communication unit should be interrupted;

sending an interrupt grant to a base site upon determining that the communication unit should be interrupted;

generating, at the base site, an interrupt message upon receiving the interrupt grant; and

broadcasting the interrupt message to the communication unit;

wherein broadcasting the interrupt message includes broadcasting the interrupt message on an outbound link of the communication channel;

wherein the inbound link is comprised of a first time division multiple access (TDMA) time slot and the outbound link is comprised of a second TDMA time slot;

wherein the second TDMA time slot is comprised of a plurality of TDMA bursts, and wherein broadcasting the interrupt message includes broadcasting at least a portion of the interrupt message within an embedded signaling information field of one or more of the plurality of TDMA bursts.

2. The method of claim 1 wherein the interrupt message includes an identification code corresponding to an identification code of the communication unit.

3. The method of claim 2 wherein the interrupt message is in the form of a link control signal.

4. The method of claim 1 wherein the interrupt message is broadcast in place of a link control signal on one or more of the plurality of TDMA bursts.

5. The method of claim 1 wherein the interrupt message is broadcast in place of message indicator encryption synchronization word on one or more of the plurality of TDMA bursts.

6. A method for interrupting a communication unit transmitting a call in a communication system, the method, at the communication unit, comprising:

initiating a call;

receiving a channel grant signal assigning the call to a communication channel;

transmitting the call on an inbound link of the communication channel;

determining whether an interrupt message has been transmitted by a base site;

determining whether the interrupt message contains an identification code matching an identification code of the communication unit; and

ceasing transmission of the call on the inbound link if the identification code contained in the interrupt message matches the identification code of the communication unit.

7. The method of claim 6 wherein determining whether the interrupt message has been transmitted by the base site includes obtaining embedded signaling information from at least one embedded signaling information field on an outbound link of the communication channel;

and determining whether the embedded signaling information includes an interrupt message.

8. The method of claim 7 wherein the inbound link is comprised of a first time division multiple access (TDMA) time slot and the outbound link is comprised of a second TDMA time slot;

and wherein obtaining embedded signaling information includes transitioning to the second TDMA time slot during a time when the communication unit is not transmitting on the first TDMA time slot, and obtaining the embedded signaling information from the embedded signaling information field in at least one TDMA burst in the second TDMA time slot.

9. The method of claim 6 further including providing a user perceivable alert upon determining the identification code contained in the interrupt message matches the identification code of the communication unit.

10. The method of claim 6 further including transmitting a call termination message to a base site.

11. The method of claim 6 wherein ceasing transmission of the call information includes dekeying from the call and switching to a control channel.

12. The method of claim 6 wherein ceasing transmission of the call information includes switching from a transmitting mode to a receiving mode.

13. A communication system capable of interrupting transmission of a call on a communication channel comprising;

a controller configured to assign the call to the communication channel, and subsequently send an interrupt grant upon determining that transmission of the call should be interrupted;

a base site coupled to the controller, the base site being configured to receive the call on an inbound link of the communication channel, to subsequently receive the interrupt grant, to generate an interrupt message upon receiving the interrupt grant, and to broadcast the interrupt message to the communication channel;

a communication unit in wireless communication with the base site, the communication unit being configured to transmit the call on the inbound link, to determine whether the interrupt message has been transmitted from the base site, and to cease transmission of the call on the inbound link upon determining that the embedded signaling information field includes the interrupt message;

wherein the base site is configured to broadcast the interrupt message to the communication channel within at least one embedded signaling information field on an outbound link of the communication channel, and wherein the communication unit is configured to obtain the at least one embedded signaling information field from the outbound link while transmitting the call on the inbound link, to determine whether the at least one embedded signaling information field includes the interrupt message;

wherein the interrupt message includes an identification code, and wherein the communication unit is further configured to cease transmission of the call on the inbound link if the identification code included in the interrupt message matches an identification code of the communication unit.

14. The system of claim 13 wherein the base site is configured to transmit the call on the outbound link only if the outbound link is not encrypted.

15. The system of claim 13 wherein the communication unit is further configured to ignore the interrupt message if the outbound link is encrypted.