An apparatus of a base station includes a memory device and processing circuitry operatively coupled to the memory device. The processing circuitry processes a buffer status report (BSR) from a user equipment (UE) indicating an amount of data in a buffer of the UE. The processing circuitry further determines a ratio of WLAN uplink data to be transmitted on a WLAN channel of the UE to long term evolution (LTE) uplink data to be transmitted on a LTE channel. Furthermore, the processing circuitry encodes a protocol data unit (PDU) indicating the amount, wherein the PDU is to be transmitted to the UE.