Implementation and evaluation of local breakout method for IP-based femtocell networks

Recently, femtocells, which cover a cell area of several tens of meters, have been attracting considerable attention in the field of mobile data communications. In the standard method, when a femtocell for data communication is connected through a public network such as a broadband access network or the Internet, an IPSec tunnel is established between the femtocell and the security gateway located in the mobile core network and all the data are exchanged over that tunnel for secure communication. Therefore, when access terminals communicate with home servers or the Internet using femtocells, communication data are sent back after transferring them to the mobile core network through the security gateway. As a result, the routing path becomes redundant and the load on the mobile core network also becomes high. In this paper, we propose local breakout methods which terminate the IP layer and set a flexible routing table on the femtocell based on the operator´s policy. The proposed methods are then evaluated using 1xEV-DO femtocell product.