Beyond Coexistence: Traffic Steering in LTE Networks with Unlicensed Bands

In this article, we study how to efficiently utilize heterogeneous network resources for various service provisioning in LTE networks with unlicensed bands. Our focus is on traffic steering, which is to intelligently distribute traffic among heterogenous cells, radio access technologies, and spectrum bands based on the desires of the network or users. We first highlight the significance of traffic steering, and then present the typical applications and approaches for traffic steering. After that, discussions on how to leverage unlicensed bands for traffic steering are provided, followed by case studies to demonstrate the benefits of traffic steering. Finally, some research issues essential for traffic steering in LTE networks with unlicensed bands are identified.