Classifying failure reports as either current or stale for mobility robustness optimization adjustments

1. A method of operation of a node in a cellular communications network, comprising: receiving a failure report associated with a connection failure for a mobile user equipment, wherein the failure report comprises a first timer value that defines an amount of time that has expired between a time at which the connection failure occurred and a time at which the mobile user equipment transmitted the failure report; determining when the connection failure occurred with respect to a most recent mobility adjustment made by the node based on the first timer value from the failure report and a second timer value that defines an amount of time that has expired since the most recent mobility adjustment was made by the node; and if the connection failure occurred before the most recent mobility adjustment made by the node, classifying the failure report as a stale failure report and considering the stale failure report with a weighting factor in a next iteration of the mobility adjustment, wherein the weighting factor is in a range between zero and one but excluding one.

2. The method of claim 1 wherein the second timer value is maintained by the node and determining when the connection failure occurred with respect to the most recent mobility adjustment made by the node comprises comparing the first timer value from the failure report to the second timer value.

3. The method of claim 1 wherein determining when the connection failure occurred with respect to the most recent mobility adjustment made by the node comprises obtaining, from another node, information indicative of a comparison of the first timer value from the failure report and the second timer value.

4. The method of claim 1 further comprising, if the connection failure occurred after the most recent mobility adjustment made by the node, classifying the failure report as a current failure report.

5. The method of claim 4 further comprising performing a subsequent process to determine whether new mobility adjustments are desired and, if so, make one or more new mobility adjustments, wherein the subsequent process does not consider the failure report if the failure report is classified as a stale failure report and does consider the failure report if the failure report is classified as the current failure report.

6. The method of claim 4 further comprising performing a subsequent process to determine whether new mobility adjustments are desired and, if so, make one or more new mobility adjustments, wherein the subsequent process considers the failure report if the failure report is classified as the current failure report and considers the failure report with a reduced relevance if the failure report is classified as a stale failure report.

7. The method of claim 1 further comprising:

making the most recent mobility adjustment;

starting the second timer upon making the most recent mobility adjustment such that the second timer defines an amount of time that has expired since making the most recent mobility adjustment;

after making the most recent mobility adjustment and starting the second timer, receiving a plurality of failure reports associated with a plurality of connection failures for a plurality of user equipments; and

for each failure report of the plurality of failure reports:

determining when a connection failure of the plurality of connection failures that corresponds to the failure report occurred with respect to the most recent mobility adjustment made by the node based on the second timer and a first timer included in the failure report that defines an amount of time that has expired between a time that the connection failure occurred and a time at which a corresponding user equipment of the plurality of user equipments transmitted the failure report;

if the connection failure occurred before the most recent mobility adjustment made by the node, classifying the failure report as a stale failure report; and

if the connection failure occurred after the most recent mobility adjustment made by the node, classifying the failure report as a current failure report.

8. The method of claim 7 further comprising:

performing a process to determine whether new mobility adjustments are desired and, if so, making one or more new mobility adjustments based on ones of the plurality of failure reports classified as current failure reports but not ones of the plurality of failure reports classified as stale failure reports; and

restarting the second timer if the process made one or more new mobility adjustments.

9. The method of claim 7 further comprising:

performing a process to determine whether new mobility adjustments are desired and, if so, making one or more new mobility adjustments based on the plurality of failure reports such that a first subset of the plurality of failure reports classified as stale failure reports are given less relevance as compared to a second subset of the plurality of failure reports classified as current failure reports; and

restarting the second timer if the process made one or more new mobility adjustments.

10. The method of claim 1 wherein the node is a base station of the cellular communications network, and receiving the failure report comprises receiving the failure report from the user equipment.

11. The method of claim 1 wherein the node is a first base station of the cellular communications network, and receiving the failure report comprises receiving the failure report from a second node of the cellular communications network.

12. The method of claim 1 wherein the node is a base station of a first radio access network operating according to a first radio access technology, and receiving the failure report comprises receiving the failure report from a node associated with a second radio access network operating according to a second radio access technology, wherein the second radio access network obtained the failure report from the user equipment.

13. A node in a radio access network of a cellular communications network, comprising: a radio subsystem configured to provide wireless connectivity to mobile user equipments located within a cell served by the node; one or more communication interfaces configured to provide connectivity to at least one of the group consisting of: a core network of the cellular communications network and one or more other nodes in the radio access network; and a processing subsystem associated with the radio subsystem and the one or more communication interfaces configured to: receive a failure report associated with a connection failure for a mobile user equipment wherein the failure report comprises a first timer value that defines an amount of time that has expired between a time at which the connection failure occurred and a time at which the mobile user equipment transmitted the failure report; determine when the connection failure occurred with respect to a most recent mobility adjustment made by the node based on the first timer value from the failure report and a second timer value that defines an amount of time that has expired since the most recent mobility adjustment was made by the node; and if the connection failure occurred before the most recent mobility adjustment made by the node, classify the failure report as a stale failure report and consider the stale failure report with a weighting factor in a next iteration of the mobility adjustment, wherein the weighting factor is in a range between zero and one but excluding one.