Dial-back call completion method and apparatus in a radio-communication system

• US 5,689,803 A
• Filed: 08/25/1995
• Issued: 11/18/1997
• Est. Priority Date: 08/25/1995
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Tayloe, Daniel Richard
• Primary Examiner(s): Pham, Chi H.
• Application Number:
  US08/519,220
• Time in Patent Office: 816 Days
• Field of Search: 455/12.1, 455/13.1, 455/33.1, 455/33.2, 455/34.1, 455/34.2, 455/54.1, 455/54.2, 379/59, 379/60, 379/209, 379/266
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18558 Arrangements for managing communications, i.e. for setting up, maintaining or releasing a call between stations

Abstract

A method and apparatus for making a call connection in a communication system (10) having multiple communication units (26) (CU), and at least one communication antenna (12) that moves with respect to the CUs (26). The method involves determining (154) whether a call attempt from a source CU (26) to a target CU (50) is successful. When the call attempt is not successful, a control facility (24) predicts (xxx) when one of the antenna (12) will move within an optimal call initiation area (124), within which there is an increased likelihood of establishing a communication link with the target CU (50). At the time when the antenna (12) will move within the optimal call initiation area (124), the system attempts to contact the target CU (50) and, if successful, informs the target CU (50) to wait while the system calls the source CU (26) and connects the call.

Claims

1. A method for establishing a communication path in a communication system having multiple communication units, at least one communication antenna that predictably changes a position with respect to a target communication unit, and at least one control facility, the method comprising the steps of:

a) determining whether a target link is successfully established when a source communication unit makes a first call attempt to establish the communication path with the target communication unit, the communication path requiring establishment of the target link between the target communication unit and one of the at least one communication antenna;

b) where the target link is not successfully established, calculating a future call opportunity when the target communication unit will have a better opportunity to support the target link because a predicted future position of one of the at least one communication antenna will have moved within an optimal call initiation area with respect to the target communication unit;

c) attempting to contact the target communication unit during the future call opportunity;

d) where attempting to contact the target communication unit is successful, requesting that the target communication unit hold while the source communication unit is contacted;

e) contacting the source communication unit; and

f) connecting the source communication unit and the target communication unit.

2. The method as claimed in claim 1 further comprising the step of:

g) sending the future call opportunity to the source communication unit so that the source communication unit has a knowledge of when the source communication unit may be contacted during the future call opportunity.

3. The method as claimed in claim 1 further comprising the steps of:

g) providing the source communication unit with an option of whether or not to have the communication system calculate the future call opportunity;

h) when the source communication unit exercises the option, performing steps b) through f; and

i) when the source communication unit does not exercise the option, not performing steps b) through f).

4. The method as claimed in claim 1 wherein the step of calculating the future call opportunity comprises the steps of:

b1) establishing an optimal call initiation area within which one of the at least one communication antenna should be located for an increased likelihood that the target link will be possible;

b2) predicting a next antenna to move within the optimal call initiation area;

b3) estimating a first time when the next antenna will enter the call initiation area;

b4) calculating the future call opportunity as the first time; and

b5) attempting to contact the target communication unit during the future call opportunity.

5. The method as claimed in claim 4 wherein the step of establishing the optimal call initiation area comprises the steps of:

b1a) determining a last-known location of the target communication unit as a most recent location of the target communication unit reported to the communication system;

b1b) calculating a call opportunity area that is defined by an angle of elevation between the last-known location and a horizon such that one of the at least one communication antenna is more likely to be able to support the target link; and

b1c) determining the optimal call initiation area as a portion of the call opportunity area, wherein the optimal call initiation area is determined so that a call between the source communication unit and the target communication unit may have a duration that is greater than a minimum acceptable call duration.

6. The method as claimed in claim 4 wherein the step of calculating the future call opportunity further comprises the steps of:

b6) determining a second time when the next antenna will exit the optimal call initiation area; and

b7) calculating the future call opportunity as times between the fast time and the second time.

7. The method as claimed in claim 1 further comprising the steps of:

g) calculating at least one additional future call opportunity; and

h) where attempting to contact the target communication unit is not successful, attempting to contact the target communication unit during the at least one additional future call opportunity.

8. A method for making a call connection in a communication system having multiple communication units, at least one satellite that predictably changes a position with respect to a surface of an earth, and at least one control facility, the method comprising the steps of:

a) making a fast call attempt by a source communication unit to establish a communication path with a target communication unit, the communication path requiting establishment of a target link between the target communication unit and a satellite;

b) determining whether the target link is successfully established;

c) where the target link is not successfully established, calculating a future call opportunity when the target communication unit will have a better opportunity to support the target link because a predicted future position of one of the at least one satellite will have moved within an optimal call initiation area with respect to the target communication unit;

d) attempting to contact the target communication unit during the future call opportunity;

e) where attempting to contact the target communication unit is successful, requesting that the target communication unit hold while the source communication unit is contacted;

f) contacting the source communication unit; and

g) connecting the source communication unit and the target communication unit.

9. A method for establishing a communication path in a communication system having multiple communication units, at least one communication antenna that predictably changes a position with respect to a target communication unit, and at least one control facility, the method comprising the steps of:

a) making a call attempt by a source communication unit to establish the communication path with a target communication unit, the communication path including a target link between the target communication unit and a target antenna that moves with respect to the target communication unit;

b) where the call attempt is not successful, waiting for the communication system to attempt to contact the target communication unit during a future call opportunity during which the target communication unit will have a better opportunity to support the target link because a predicted future position of one of the at least one communication antenna will have moved within an optimal call initiation area with respect to the target communication unit;

c) the source communication unit being contacted by the communication system when the communication system successfully contacts the target communication unit; and

d) establishing the communication path with the target communication unit.

10. The method as claimed in claim 9 further comprising the steps of:

e) the source communication unit being provided an option by the communication system of whether or not to have the communication system contact the target communication unit during the future call opportunity;

f) presenting a user of the source communication unit with the option;

g) when the user indicates that the user wants to exercise the option, performing steps b) through d); and

h) when the user indicates that the user does not want to exercise the option, not performing steps b) through d).

11. The method as claimed in claim 9 further comprising the step of:

e) receiving from the communication system the future call opportunity so that the source communication unit has a knowledge that the source communication unit may be contacted during the future call opportunity.

12. The method as claimed in claim 9 wherein the step of waiting for the communication system to attempt to contact the target communication unit comprises the steps of:

b1) establishing an optimal call initiation area within which one of the at least one communication antenna should be located for an increased likelihood that the target link will be possible;

b2) predicting a next antenna to move within the optimal call initiation area;

b3) estimating a first time when the next antenna will enter the optimal call initiation area;

b4) calculating the future call opportunity as the first time; and

b5) attempting to contact the target communication unit during the future call opportunity.

13. The method as claimed in claim 12 wherein the step of establishing the optimal call initiation area comprises the steps of:

b1a) determining a last-known location of the target communication unit as a most recent location of the target communication unit reported to the communication system;

b1b) calculating a call opportunity area that is defined by an angle of elevation between the last-known location and a horizon such that one of the at least one communication antenna is more likely to be able to support the target link; and

b1c) determining the optimal call initiation area as a portion of the call opportunity area, wherein the optimal call initiation area is determined so that a call between the source communication unit and the target communication unit may have a duration that is greater than a minimum acceptable call duration.

14. A communication unit comprising:

a transceiver for receiving messages from at least one antenna that moves with respect to the communication unit; and

a processor coupled to the transceiver for making a call attempt to establish a communication path with a target communication unit, the communication path including a target link between the target communication unit and a target antenna that moves with respect to the target communication unit, where the call attempt is not successful, waiting for a communication system to attempt to contact the target communication unit during a future call opportunity during which the target communication unit will have a better opportunity to support the target link because a predicted future position of one of the at least one antenna will have moved within an optimal call initiation area with respect to the target communication unit, if the communication system successfully contacts the target communication unit, being called by the communication system, and establishing the communication path with the target communication unit.

15. The communication unit as claimed in claim 14 wherein the processor is also for being provided with an option of whether or not to have the communication system contact the target communication unit during the future call opportunity, the communication unit further comprising:

a display device coupled to the processor for displaying the option to a user of the communication unit; and

an input device coupled to the processor for allowing the user to input information indicating that the user wants to exercise the option.

16. A call opportunity calculation apparatus comprising:

a transceiver for sending messages to a source communication unit;

a processor coupled to the transceiver for determining whether the source communication unit has successfully established a communication path with a target communication unit, the communication path including a target link between the target communication unit and at least one antenna that moves with respect to the target communication unit, the processor also for calculating a future call opportunity at which the source communication unit will have a better opportunity to establish the target link because a predicted future position of one of the at least one antenna will be within an optimal call initiation area with respect to the target communication unit, attempting to contact the target communication unit during the future call opportunity, where attempting to contact the target communication unit is successful, requesting that the target communication unit hold while the source communication unit is contacted, contacting the source communication unit, and connecting the source communication unit and the target communication unit; and

a memory device coupled to the processor for storing information necessary to calculate the future call opportunity.