Differential routing of voice handover traffic and non-voice handover traffic in response to congestion on an inter-base-station interface

A method operable in a wireless communication system comprising a controller and first and second base stations, wherein the first and second base stations are communicatively linked via (i) a backhaul interface that passes through the controller and (ii) an inter-base-station interface that does not pass through the controller, the method comprising:

• serving, by the wireless communication system, a user equipment device (UE) over an air interface connection between the UE and the first base station;
• while serving the UE, the wireless communication system (i) encountering a trigger to hand over the UE from being served by the first base station to being served by the second base station and (ii) determining that a congestion level of the inter-base-station interface is at or above a threshold congestion level;
• in response to encountering the trigger and to determining that the congestion level of the inter-base-station interface is at or above the threshold congestion level, making a determination, by the wireless communication system, of whether the UE is engaging in voice communications;
• if the determination is that the UE is engaging in voice communications, then, responsive to making the determination, the wireless communication system transmitting via the inter-base-station interface rather than via the backhaul interface handover signaling to hand over the UE from being served by the first base station to being served by the second base station;
• and
• if the determination is that the UE is not engaging in voice communications, then, responsive to making the determination, the wireless communication system transmitting via the backhaul interface rather than via the inter-base-station interface handover signaling to hand over the UE from being served by the first base station to being served by the second base station.

A wireless communication system comprising:

• a backhaul-network entity;
• a backhaul interface that passes through the backhaul-network entity;
• an inter-base-station interface that does not pass through the backhaul-network entity;
• first and second base stations that are communicatively linked via (i) the backhaul interface and (ii) the inter-base-station interface;
• and
• a controller configured to cause the wireless communication system to perform operations comprising:
• encountering a trigger to configure transmission of handover signaling between the first and second base stations;
• in response to encountering the trigger, configuring the wireless communication system to transmit (i) via the inter-base-station interface rather than via the backhaul interface handover signaling that facilitates handover between the first and second base stations of ongoing voice communications and (ii) via the backhaul interface rather than via the inter-base-station interface handover signaling that facilitates handover between the first and second base stations of communications other than ongoing voice communications;
• and
• transmitting handover signaling based on the configuring.