Performance of SON for RSRP-based LTE/WLAN access network selection

Carrier-grade Wireless Local Area Network (WLAN) is becoming an important complementary system to cellular networks for Mobile Network Operators (MNOs). Network controlled access network selection between cellular and WLAN is an essential functionality to optimize network performance and user experience. Automated configuration and optimisation of the network selection mechanism is of utmost importance in the emerging complex heterogeneous networks. In this article, we present and evaluate a Self-Organizing Network (SON) scheme for optimizing autonomously the access network selection between the Long Term Evolution (LTE) and WLAN systems. The adopted access network selection mechanism uses the standard LTE Received Reference Signal Power (RSRP) measurements available at the User Equipment (UE) and a set of simple rules based on network-provided RSRP thresholds. The proposed SON mechanism is using the LTE cell load estimated at the evolved NodeB (eNB) to update the RSRP thresholds in order to achieve the best load balancing in the network. Simulation results in a realistic network highlight the benefits of the proposed SON mechanism and possible further improvements.