Smart IP Flow and Mobility Management Techniques

QoE-based IP flow management in wireless heterogeneous networks

Nowadays, a significant fraction of mobile devices in the market is equipped with multiple wireless interfaces. These technologies have been developed separately and therefore offer different coverage, data rate and services. Let us report two classic examples. Cellular networks have been designed to have high coverage area, low/medium data rates and mainly to provide speech services. On the contrary, IEEE 802.11 WLANs have been designed for local and small areas, medium/high data rates and mainly for data services. Such technologies can coexist in the same environment and also interwork so as to create a heterogeneous platform able to offer more services, higher coverage and higher data rates to mobile end-users.

An example of data striping

An example of data striping

We study two main topics in this framework:

Vertical Mobility Management

We study the three aspects of the mobility management: user/node reachability, handover decision and handover execution. Currently, our research is mainly focused on group mobility management for vehicular environment and in particular on:

  • how to identify a group of users as a single entity,
  • SIP assisted group mobility.

Data Striping

The main issues we investigate are:

  • packet allocation policy through multiple communication paths at the source node;
  • inter-packet coding techniques (e.g., digital fountain codes).

Offloading Strategies for Advances Mobile Networks

Analytical framework for modeling traffic offloading

  • impact that offloading techniques might have on the networks of MNOs
      • performance limits of network resource needs when deploying offloading (network dimensioning issues).
      • benefits of offloading (if any) by comparing the required network resources before and after offloading.
      • benefits of the energy consumption of a cellular system after offloading to small cells of a HetNet


    Ratio between the required capacity before (Cy) and after (Cz) offloading depending on the tail-index of offloading periods.










New architectural approach to support advanced mobility features

  • Towards a more flexible Evolved Packet System
    • to fulfill current and future requirements
      • e.g., multihoming, offloading, route optimization
    • the key design principles are:
      • a generalized use of traffic flow templates (TFTs) for a more flexible IP flow handling,
      • a full decoupling of control and user plane for flexibility,
      • an on-demand (or pull-based) state set up in network nodes for scalability.

CTTC external report  “Fundamental analysis of the EPS architecture facing future data networking needs“, November, 2012

Algorithms for smart IP Flow and Mobility Management

  • algorithms for smartphones to control offloading periods
    • based on relation between traffic patterns, mobility patterns, and distribution of offloading points
  • algorithms to offer a richer mobility experience
    • based on monitoring of individual IP flow routing between different access networks

Distributed location management in cellular networks

Location Management (LM) comprises the set of procedures and algorithms aimed at tracking the location of a UE in a cellular network. In the context of Networks of Femtocells (NoFs), UEs may experience a substantial number of cell reselections and handovers in relatively short periods of time. Consequently, LM must solve the scalability problem in terms of location signalling traffic towards the Mobility Management Entity (MME) at the EPC. Another scalability problem is caused by the large-scale, all-wireless backbone, in case all-wireless NoFs are considered. In this scenario, the goal is to minimize over-the-air signalling traffic.

In order to address these challenges, we have focused our efforts on two areas:

1) Minimize the volume of location signalling traffic generated from the UE to the MME during Tracking Area Update procedures. In order to do so, we have designed a Self-Organized Tracking Area List Mechanism that dynamically adapts the size of individual TALs to the mobility state of each UE.

Standard Tracking Area Update Mechanism Self-Organized Tracking Area List Mechanism

2) Minimize the volume of location signalling traffic generated from the MME to the UE during Paging procedures. In order to do so, we have designed a Distributed Paging Mechanism over the X2 interface that combines unicast and multicast forwarding schemes to page UEs more efficiently.
In the past, we also carried out some work on distributed location management for wireless mesh networks by means of geographic hash tables. We designed and implemented in Click a scheme called VIrtual home-region Multi-hash LOCation service (VIMLOC). See also this page on distributed location management in Wireless Mesh Networks.

Video Gallery

You may also be interested in the talks we gave during the Femtocells Winter School 2012:


QoE-based IP flow management

Offloading strategies and architectural approach to support advanced mobility features

  • A. Rodríguez Natal, L. Jakab, M. Portoles-Comeras, V. Ermagan, P. Natarajan, F. Maino, D. Meyer, A. Cabellos-Aparicio, LISP-MN: Mobile Networking through LISP, Springer Wireless Personal Communications Journal, Vol. 65, June 2012.
  • A. Krendzel “LTE-A Mobile Relay Handling: Architecture Aspects”, accepted for the 19th European Wireless Conference (EW-2013), 16-18 April, Guildford, United Kingdom, 2013

Distributed location management