A method and system for controlling apportionment of uplink data flow of a UE having a first connection with a first access node and a second connection with a second access node. An example system could operate to determine an uplink data apportionment, defining what portion of the uplink data flow the UE should provide on the first connection versus what portion of the uplink data flow the UE should provide on the second connection, where determining the uplink data apportionment is based on (i) a comparison of uplink power headroom of the UE on the first connection with uplink power headroom of the UE on the second connection and/or (ii) a comparison of uplink noise on the first connection with uplink noise on the second connection. Further, the example system could then cause the UE to operate in accordance with the determined uplink data apportionment.