Methods for removing sectors from a mobile station active set using history of prior removals
View Patent ↗Communication on a sector in a mobile station's active set is eliminated in order to test whether such elimination has a sufficiently adverse impact on RF communication with the mobile station on the remaining sectors in the active set. If it is determined that the elimination of the sector has a sufficiently adverse impact, communication on the sector is restored. Otherwise, the sector is removed from the mobile station's active set, thereby freeing up a soft hand-off resources, including a channel element and a Walsh code, for use by other mobile stations. A log or history of the event is maintained, including the location of the mobile station at the time of the removal. From such history, a correlation between defined geographical areas and removed sectors in active sets can be derived. The correlations, e.g., in a form of a table, can be used as a means for identifying one or more sectors to drop when a mobile device roams into one of the defined geographic areas.
1. A method for managing communication between one or more base transceiver stations and a mobile station, said communication occurring on a set of sectors forming an active set, comprising steps of:
(a) maintaining a history of removals of sectors from active sets for mobile stations operating in area served by a base transceiver station;
(b) using the history to identify at least one sector that has been removed as a member of an active set for at least one other mobile station operating in the same geographic area as that of the mobile station; and
(c) rejecting a request from the mobile station to add the at least one identified sector to the active set of the mobile station,
wherein the history maintained in step (a) further comprises a history of events in which a sector was not removed from an active set for mobile stations operating in the area.
2. A method for managing communication between one or more base transceiver stations and a mobile station, said communication occurring on a set of sectors forming an active set, comprising steps of:
a) determining, at least approximately, the location of the mobile station;
b) determining whether the mobile station has a sector in its active set which can be removed from the active set based on a prior history of removal of the sector from active sets of other mobile stations located in an area encompassing the current location of the mobile station,
c) if the determination in step b) is affirmative, removing the sector from the active set of the mobile station; and
d) subsequently rejecting a request by the mobile station to add the sector to its active set; wherein the method further comprises the steps of accepting a request from a second mobile station operating in the geographic area to add the at least one identified sector to its active set, removing the sector from the second mobile station's active set, and determining the effect of elimination of the sector from the active set.
3. A method for managing communication between one or more base transceiver stations and a mobile station, said communication occurring on a set of sectors forming an active set, comprising steps of:
a) intentionally eliminating communication between a base transceiver station and the mobile station on a selected sector in the active set;
b) determining the effect of the elimination on communication between the mobile station and at least one other remaining sector in the active set;
c) either restoring communication on the selected sector or removing the selected sector from the active set, based on the determination in step b);
d) maintaining a history of the event; and
e) periodically testing the effect of removal of a sector
from the active set of a mobile station operating in one or more geographic areas,
wherein the periodic testing is performed on the basis of a user-configurable time period.
4. The method of claim 3 , wherein the method further comprises the step of deriving from the history of the one or more geographic areas where at least one sector has been removed from mobiles stations' active sets and associating such geographic areas with the at least one sector.
5. The method of claim 4 , further comprising the step of denying a request to add a sector in the at least one sector to a second mobile station's active set when the second mobile station is located in the one or more derived geographic areas.
6. The method of claim 5 , wherein a multitude of geographic areas are derived from the history, each area associated with one or more sectors, and wherein a request from a mobile station to add one of the associated sectors to its active set is denied when the mobile station is located in one of the associated geographic areas.
7. The method of claim 6 , further comprising the step of deriving from the history one or more geographic areas where testing of removal of one or more sectors from an active set of a mobile station in the geographic area has indicated that the one or more sectors could not be removed from the active set without an adverse consequence.
8. The method of claim 3 , wherein the periodic testing is performed on the basis of a user-configurable number of calls occurring with mobile stations located in the geographic area.
9. The method of claim 3 , further comprising the step of performing an initial screening of the mobile station to see if it is a candidate for step (a) and conducting step (a) if the initial screening is passed.
10. The method of claim 9 , wherein the initial screening involves consideration of at least one of the following parameters for the mobile station: (a) frame error rate, (b) ratio of E c /I o and (c) transmission power level of either a base transceiver station or the mobile station.