X2-Interface-basedlocation management for Small Cell networks

Small Cells (SCs) have emerged as one of the main solutions to the exponential growth of data in mobile networks. Still, some key challenges lack an adequate solution for SCs to reach its full potential. Among these challenges, location management is responsible for keeping track of users´ location, necessary for sending and receiving calls. This essential function is performed through two operations: Location Updates (LUs) and paging. The standard solution for location management provided by 3GPP defines LU and paging with Tracking Area List (TAL) granularity. However, these procedures are no longer appropriate in SCs for two reasons: first, smaller coverage areas increase mobility among cells; second, backhaul capacity limitations set tighter restrictions on the signaling load. In this paper, two schemes for location update and paging are proposed, namely, X2-Interface-based scheme with SC updates and X2-Interface-based scheme with Tracking Area (TA) updates. These schemes reduce paging through the use of a local anchor to keep track of users´ location inside the TAL. Furthermore, the processing cost is reduced by allowing connectivity among SCs through the X2 interface. The numerical results show that the proposed solutions reduce the total cost associated with location update and paging in relation to the 3GPP-based scheme with TAL granularity.