Design and Analysis of Optimal Threshold Offloading (OTO) Algorithm for LTE Femtocell/Macrocell Networks

LTE femtocells have been commonly deployed by network operators to increase network capacity and offload mobile data traffic from macrocells. A User Equipment (UE) camped on femtocells has the benefits of higher transmission rate and longer battery life due to its proximity to the base stations. However, various user mobility behaviors may incur network signaling overhead and degrade femtocell offloading capability. To efficiently offload mobile data traffic, we propose an optimal Threshold Offloading (TO) algorithm considering the trade-off between network signaling overhead and femtocell offloading capability. In this paper, we develop an analytical model to quantify the trade-off and validate the analysis through extensive simulations. The results show that the TO algorithm can significantly reduce signaling overhead at minor cost of femtocell offloading capability. Moreover, this work offers network operators guidelines to set optimal offloading threshold in accordance with their management policies in a systematical way.