Characterizing performance of load-aware network selection in multi-radio (WiFi/LTE) heterogeneous networks

In this paper, we consider the problem of network selection between different radio access technologies (RATs) deployed as part of an operator managed multi-RAT heterogeneous network. An urban deployment scenario is studied where WiFi small cells are overlaid on top of the 3GPP LTE network. We assume limited cooperation across the multi-RAT network and emphasize user-centric network selection algorithms to minimize feedback overhead and to better account for user preferences. Specifically, we investigate schemes that rely on network loading information with suitable adaptation of hysteresis mechanisms and compare them with WiFi-preferred schemes that only account for signal strength measurements. We also benchmark the performance of load-aware schemes against conventional cellrange extension methods that use network-wide optimization to offload users to small cells. The results of our systemlevel performance evaluation show that load-aware user-centric schemes can provide improved performance compared to the WiFi-preferred schemes and may even outperform network-based cell-range extension schemes under some conditions.