Adaptive RF link failure handler

• US 7,489,928 B2
• Filed: 12/31/2002
• Issued: 02/10/2009
• Est. Priority Date: 12/31/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Smith, Brian K.
• Primary Examiner(s): Nguyen; Tu X
• Application Number:
  US10/334,472
• Publication Number:
  US 20040203441A1
• Time in Patent Office: 2,233 Days
• Field of Search: 455/437, 455/444, 455/522, 455432-435, 455/441, 455/440, 455/436, 455/69, 455/404.2, 455/439, 455/442
• US Class Current: 455/432.1
• CPC Class Codes: H04B 17/23 Indication means, e.g. displays, alarms, audible means
• CPC Class Codes: H04B 17/391 Modelling the propagation channel
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition

Abstract

A method for preventing radio frequency (RF) link failures in a radio telecommunication network. The network includes at least one base station (402) and at least one subscriber unit (SU) (406) which are capable of sending and receiving RF link signals. The method provides for monitoring the RF link between the base station (402) and the SU (406) and determining if the RF link is failing (216), and if so, taking corrective action to maintain the RF Link. The method provides for storing information about the RF Link failure and the corrective action taken (224) and utilizes the corrective action taken in prior RF Link failures to prevent future RF Link failures. The method provides for determining that an old corrective action for improving the RF Link channel quality no longer improves the RF Link channel quality and, therefore, provides for discarding the old corrective action in favor of a new corrective action (234).

Claims

1. A cellular subscriber unit (SU) adaptively learning radio frequency (RF) link coverage in a radio telecommunication network, the cellular subscriber unit comprising:

a memory; and

a controller coupled to the memory and operable to provide an adaptive RF link failure handler to learn and adapt RF link failure protocols to an RF environment in which the SU is operated, the adaptive RF link failure handler storing coverage information associated with RF link failures in the memory,

wherein the controller determines that a current RF link failure event is similar to a prior RF link failure event, retrieves a corrective action taken in the prior RF Link failure event; and

, implements the corrective action to improve the RF Link channel quality.

2. The cellular subscriber unit of claim 1 further comprising a global positioning system receiver incorporated into the SU capable of accurately determining the SU'"'"'s location, the coverage information associated with a link failure event including the position of the SU determined by the global positioning system receiver.

3. The cellular subscriber unit of claim 1 wherein when a base station with which the subscriber unit is connected is capable of accurately determining the SU'"'"'s location and communicating it to the subscriber unit, the coverage information associated with a link failure event including the position of the SU as received from the base station.

4. The system of claim 1 wherein the SU is capable of accurately determining the SU'"'"'s location with the assistance of the base station, the coverage information associated with a link failure event including the position of the SU.

5. A method for prevention of radio frequency (RF) link failures in a subscriber unit for a radio telecommunication network, the method comprising:

monitoring in the subscriber unit the RF link between the subscriber unit (SU) and a base station;

determining in the subscriber unit that the RF link has failed;

determining the RF Link failure event is similar to a prior RF Link failure event;

retrieving a corrective action taken in the prior RF Link failure event; and

attempting to implement the corrective action to improve a RF Link channel quality;

determining in the subscriber unit that the corrective action improves the RF Link channel quality;

storing in the subscriber unit information about the failed RF Link, and the corrective action taken to improve the RF Link channel quality; and

,

determining in the subscriber unit that the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event.

6. The method of claim 5 further comprising the steps of:

determining a quality measurement for the RF Link channel;

comparing the RF Link channel quality measurement to a preset minimum acceptable channel quality;

determining the RF link channel quality has fallen below the minimum acceptable channel quality;

determining one or more of a location of the SU, a velocity of the SU or a direction of travel of the SU; and

comparing the one or more of the location, velocity or direction of travel of the SU when a current RF Link is failing to a prior RF Link failure event stored in memory.

8. The method of claim 5 further comprising the step of:

relaying information about the RF link failure and the corrective action taken from the base station to SU'"'"'s in an area surrounding and including the RF Link failure event.

7. A method for prevention of radio frequency (RF) link failures in a subscriber unit for a radio telecommunication network, the method comprising:

monitoring in the subscriber unit the RF link between the subscriber unit (SU) and a base station;

determining in the subscriber unit that the RF link has failed;

determining in the subscriber unit that a corrective action improves the RF Link channel quality;

storing in the subscriber unit information about the failed RF Link, and the corrective action taken to improve the RF Link channel quality;

determining in the subscriber unit that the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event;

implementing in the subscriber unit the corrective action and notifying the base Station;

determining a frequency of an RF link failure event has decreased and a prior corrective action no longer improves channel quality for the decreased RF Link failure event and discarding the corrective action;

determining in the subscriber unit that the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event; and

,

notifying the base station.

9. A method for prevention of radio frequency (RF) link failures in a radio telecommunication network, the method comprising:

monitoring the RF link between a subscriber unit (SU) and a base station;

determining the RF link has failed;

attempting a corrective action;

determining the corrective action improves the RF Link channel quality;

storing information about the failing RF Link and the corrective action taken to improve the RF Link channel quality;

determining the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event;

implementing the corrective action and notifying the base station;

determining a quality measurement for the RF Link channel;

comparing the RF Link channel quality measurement to a preset minimum acceptable channel quality;

determining the RF link channel quality has fallen below the minimum acceptable channel quality;

determining one or more of a location of the SU, a velocity of the SU or a direction of travel of the SU;

comparing the one or more of the location, velocity or direction of travel of the SU when a current RF Link is failing to a prior RF Link failure event stored in memory;

determining the current failing RF Link event is similar to a prior RF Link failure event;

retrieving the corrective action taken in the prior RF Link failure event; and

implementing the prior corrective action to improve the RF Link channel quality.

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

determining a frequency of an RF link failure event has decreased and a prior corrective action no longer improves channel quality for the decreased RF Link failure event; and

discarding the corrective action and notifying the base station.

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

relaying information about the RF link failure and the corrective action taken from the base station to SU'"'"'s in an area surrounding and including the RF Link failure event.

12. A method for prevention of radio frequency (RF) link failures in a radio telecommunication network, the method comprising:

monitoring the RF link between a subscriber unit (SU) and a base station;

determining the RF link has failed;

attempting a corrective action;

determining the corrective action improves the RF Link channel quality;

storing information about the failing RF Link and the corrective action taken to improve the RF Link channel quality;

determining the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event;

implementing the corrective action and notifying the base station;

determining a quality measurement for the RF Link channel;

comparing the RF Link channel quality measurement to a preset minimum acceptable channel quality;

determining the RF link channel quality has fallen below the minimum acceptable channel quality;

determining one or more of a location of the SU, a velocity of the SU or a direction of travel of the SU;

comparing the one or more of the location, velocity or direction of travel of the SU when a current RF Link is failing to a prior RF Link failure event stored in memory;

determining the current failing RF Link event is similar to a prior RF Link failure event;

retrieving the corrective action taken in the prior RF Link failure event;

implementing the prior corrective action to improve the RF Link channel quality;

determining a frequency of an RF link failure event has decreased and a prior corrective action no longer improves channel quality for the decreased RF Link failure event; and

discarding the corrective action and notifying the base station.

13. The method of claim 12 further comprising the step of:

relaying information about the RF link failure and the corrective action taken from the base station to SU'"'"'s in an area surrounding and including the RF Link failure event.

14. A method for prevention of radio frequency (RF) link failures in a radio telecommunication network, the method comprising:

monitoring the RF link between a subscriber unit (SU) and a base station;

determining the RF link has failed;

attempting a corrective action;

determining the corrective action improves the RF Link channel quality;

storing information about the failing RF Link and the corrective action taken to improve the RF Link channel quality;

determining the frequency of an RF link failure event has increased and the corrective action improves channel quality for the increased RF Link failure event;

implementing the corrective action and notifying the base station;

determining a quality measurement for the RF Link channel;

comparing the RF Link channel quality measurement to a preset minimum acceptable channel quality;

determining the RF link channel quality has fallen below the minimum acceptable channel quality;

determining one or more of a location of the SU, a velocity of the SU or a direction of travel of the SU;

comparing the one or more of the location, velocity or direction of travel of the SU when a current RF Link is failing to a prior RF Link failure event stored in memory;

determining the current failing RF Link event is similar to a prior RF Link failure event;

retrieving the corrective action taken in the prior RF Link failure event;

implementing the prior corrective action to improve the RF Link channel quality;

determining a frequency of an RF link failure event has decreased and a prior corrective action no longer improves channel quality for the decreased RF Link failure event;

discarding the corrective action and notifying the base station; and

relaying information about the RF link failure and the corrective action taken from the base station to SU'"'"'s in an area surrounding and including the RF Link failure event.