Mobile data offloading has been proposed as a solution for network congestion. However, the majority of the state-of-the-art is focused on the downlink offloading, while the change of mobile user habits, like mobile content creation and uploading, makes uplink offloading a rising issue. In this work we focus on the uplink offloading using Ip Flow Mobility (IFOM). IFOM allows a LTE mobile User Equipment (UE) to maintain two concurrent data streams, one through LTE and the other through WiFi access technology, that presents uplink limitations due to the inherent fairness design of IEEE 802.11 DCF. In this paper, we propose two uplink offloading algorithms to improve the energy efficiency of the UEs and to increase the offloaded data volume under the concurrent use of access technologies that IFOM provides. In the first algorithm, UEs with heavy traffic are promoted and are given priority in accessing the WiFi Access Point (AP) to offload their data. In the second algorithm, we propose a proportionally fair bandwidth allocation over the data volume needs of the UEs. We theoretically analyse the proposed algorithms and evaluate their performance through simulations. We compare their performance with the 802.11 DCF access scheme and with a state of the art access algorithm under different number of offloading UEs. Through the provided evaluation we show that there is room for improvement in the uplink access scheme of the WiFi that affects the energy efficiency of a UE during IFOM uplink offloading.

Peer Reviewed