Distributed Location Management for Generalized HetNets. Case Study of All‐Wireless Networks of Femtocells

The 3GPP vision of HetNets usually focuses on the interaction in terms of resource management between macrocells and smaller cells of 3GPP access technologies (e.g. LTE). In this chapter, we extend/generalize the HetNet vision along various lines. First, we consider diverse wireless technologies (e.g. WiFi) not just for access, but also for the backhaul. Second, we study the implications of HetNet deployments at the radio resource management level, and at the architectural level. Our architecture decentralizes some relevant functionality defined by 3GPP for a more efficient operation of the network, particularly in local networks. Finally, we combine/integrate schemes coming from the data networking community with those defined in the 3GPP architecture. We benefit from the generic network of femtocells concept coined in the framework of EU project BeFEMTO. Here we make a case for large‐scale all‐wireless networks of femtocells, that is, wireless mesh networks of femtocells that confine local procedures to the local network. Such deployment approach is supported at the architectural level by two main components: (a) a new node, referred to as Local network of Femtocells GateWay (LFGW), and (b) a geographic underlay network. The former allows scaling the signaling towards the core by appropriately confining it to the local network, and the latter allows scaling in terms of signaling internal to the network of femtocells by reducing the overhead sent over the air. Still, despite these modifications, the evolved packet core and UE remain unchanged. In this scenario, there are many issues to solve. In particular, we focus on mobility management and particularly on location management. In our scheme, the underlay network intercepts relevant 3GPP messages related to location management and, without any modification, uses them to trigger location procedures internal to the network of femtocells. In fact, we adapt to the 3GPP context a location management scheme called VIMLOC, which was designed for large‐scale wireless mesh networks and exploits geographic information to obtain scalability. Some relevant message sequence charts are presented to illustrate the operation of our solution.