Practical device-centric WiFi/cellular link aggregation mechanism for mobile devices

One key enhancement in recent 3GPP cellular standard releases is WiFi/cellular network inter-operation and integration with protocols and techniques that can optimize target performance metrics. 3GPP specifications focus on network- centric solutions that require the involvement of the cellular operator in the WiFi/cellular connection and mobility management procedures. Even though this provides notable gains due to the centralized control, its implementation requires network upgrades and is relatively complex which limits the possibility of quick market penetration. In this work, we present a practical and effective device-centric WiFi/cellular link aggregation mechanism that can boost the download bit rate and minimize the download delay. The proposed mechanism is self-adaptive and achieves optimized aggregated download bit rate without the need for link quality estimation information, changes to the WiFi or cellular standards, or proxy server configuration. Moreover, it can be customized to support different service classes as shown for file downloading and video streaming applications. We do extensive testing using an experimental implementation over Android smartphones in order to demonstrate the practical feasibility of the proposed mechanism and to quantify its performance gains under different operational conditions.