Use of per-connection fading as basis for dynamic control of Air-Interface communication with dual-connected device

1. A method for controlling data split of a dual-connected user equipment device (UE) when the UE has at least two co-existing air-interface connections including a first air-interface connection with a first access node on one or more first cells and a second air-interface connection with a second access node on one or more second cells, the method comprising:

comparing a level of fading of the first air-interface connection with a level of fading of the second air-interface connection, wherein the level of fading of the first air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more first cells, and the level of fading of the second air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more second cells;

based at least on the comparing, establishing a split ratio that defines a distribution of data flow of the UE between at least the first air-interface connection and the second air-interface connection; and

based on the establishing, causing the established split ratio to be applied.

2. The method of claim 1 , wherein the established split ratio is an uplink split ratio, and wherein causing the established split ratio to be applied comprises transmitting to the UE a directive that causes the UE to apply the established split ratio.

3. The method of claim 1 , wherein the established split ratio is a downlink split ratio, wherein an entity splits downlink data flow of the UE between the first air-interface connection and the second air-interface connection, and wherein causing the established split ratio to be applied comprises causing the entity to apply the established split ratio.

4. The method of claim 1 , wherein the method is carried out by at least one of the first access node and the second access node.

5. The method of claim 1 , further comprising:

determining the level of fading of the first air-interface connection; and

determining the level of fading of the second air-interface connection,

wherein comparing the level of fading of the first air-interface connection with the level of fading of the second air-interface connection comprises comparing the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection.

6. The method of claim 5 , wherein establishing the split ratio based on the comparing of the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection comprises establishing the split ratio based on an inverse of a ratio of (i) the determined level of fading of the first air-interface connection to (ii) the determined level of fading of the second air-interface connection.

7. The method of claim 6 , wherein establishing the split ratio based on the ratio of the determined level of fading of the first air-interface connection to the determined level of fading of second air-interface connection comprises establishing the split ratio to be equal to the inverse of the ratio of (i) the determined level of fading of the first air-interface connection to (ii) the determined level of fading of the second air-interface connection.

8. The method of claim 5 , wherein establishing the split ratio based on the comparing of the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection comprises:

selecting one of the first and second air-interface connections based on the determined level of fading of the identified air-interface connection being lower than the determined level of fading of the other of the first and second air-interface connections; and

based on the selecting, establishing as the split ratio a split ratio that will put a majority of the data flow of the UE on the selected air-interface connection.

9. The method of claim 1 , wherein the first air-interface connection operates in accordance with a first ratio access technology (RAT) and the second air-interface connection operates in accordance with a second RAT different than the first RAT.

10. A method for controlling uplink communication from a user equipment device (UE) when the UE has at least two co-existing air-interface connections including a first air-interface connection with a first access node on one or more first cells and a second air-interface connection with a second access node on one or more second cells, wherein one of the first and second air-interface connections defines a primary uplink path of the UE to which the UE restricts uplink user-plane transmission from the UE unless and until a trigger condition causes the UE to split the uplink user-plane transmission between the first and second air-interface connections, the method comprising:

comparing a level of fading of the first air-interface connection with a level of fading of the second air-interface connection, wherein the level of fading of the first air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more first cells, and the level of fading of the second air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more second cells;

selecting, based at least on the comparing, one of the first and second air-interface connections to be the primary uplink path of the UE; and

causing the UE to operate in accordance with the selecting.

11. The method of claim 10 , wherein the method is carried out by a given one of the first and second access nodes, and wherein causing the UE to operate in accordance with the selecting comprises transmitting from the given access node to the UE a directive that causes the UE to use the selected air-interface connection as the primary uplink path of the UE.

12. The method of claim 10 , wherein selecting, based at least on the comparing, one of the first and second air-interface connections to be the primary uplink path of the UE comprises:

determining, based on the comparing, that the level of fading of the first air-interface connection is less than the level of fading of the second air-interface connection; and

based at least on the determining, selecting the first air-interface connection to be the primary uplink path of the UE.

13. The method of claim 10 , further comprising:

determining the level of fading of the first air-interface connection; and

determining the level of fading of the second air-interface connection,

wherein comparing the level of fading of the first air-interface connection with the level of fading of the second air-interface connection comprises comparing the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection.

14. A computing system configured to control data split of a dual-connected user equipment device (UE) when the UE has at least two co-existing air-interface connections including a first air-interface connection with a first access node on one or more first cells and a second air-interface connection with a second access node on one or more second cells, the computing system comprising:

a processor;

non-transitory data storage; and

program instructions stored in the non-transitory data storage and executable by the processor to cause the computing system to carry out operations including:

comparing a level of fading of the first air-interface connection with a level of fading of the second air-interface connection, wherein the level of fading of the first air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more first cells, and the level of fading of the second air-interface connection is based on a level of fluctuation of coverage quality over time experienced by one or more UEs served on the one or more second cells,

based at least on the comparing, establishing a split ratio that defines a distribution of data flow of the UE between at least the first air-interface connection and the second air-interface connection, and

based on the establishing, causing the established split ratio to be applied.

15. The computing system of claim 14 , wherein the computing system is at a given one of the first and second access nodes.

16. The computing system of claim 14 , wherein the established split ratio is an uplink split ratio, and wherein causing the established split ratio to be applied comprises transmitting to the UE a directive that causes the UE to apply the established split ratio.

17. The computing system of claim 14 , wherein the established split ratio is a downlink split ratio, wherein an entity splits downlink data flow of the UE between the first air-interface connection and the second air-interface connection, and wherein causing the established split ratio to be applied comprises causing the entity to apply the established split ratio.

18. The computing system of claim 14 ,

wherein the operations further include (i) determining the level of fading of the first air-interface connection and (ii) determining the level of fading of the second air-interface connection, and

wherein comparing the level of fading of the first air-interface connection with the level of fading of the second air-interface connection comprises comparing the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection.

19. The computing system of claim 18 , wherein establishing the split ratio based on the comparing of the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection comprises establishing the split ratio based on an inverse of a ratio of (i) the determined level of fading of the first air-interface connection to (ii) the determined level of fading of the second air-interface connection.

20. The computing system of claim 18 , wherein establishing the split ratio based on the comparing of the determined level of fading of the first air-interface connection with the determined level of fading of the second air-interface connection comprises:

selecting one of the first and second air-interface connections based on the determined level of fading of the identified air-interface connection being less than the determined level of fading of the other of the first and second air-interface connections; and

based on the selecting, establishing as the split ratio a split ratio that will put a majority of the data flow of the UE on the selected air-interface connection.