Telemaco Melia

An overview of IEEE 802.21: media-independent handover services

In recent years multitechnology-enabled terminals have become available. Such multimode terminals pose new challenges to mobility management. In order to address some of these challenges, the IEEE is currently working on a new specification on media-independent handover services (IEEE 802.21 MIH). The main aim of this specification is to improve user experience of mobile terminals by enabling handovers between heterogeneous technologies while optimizing session continuity. In this article we provide an overview of the current status of the IEEE 802.21 specification.

IP flow mobility: smart traffic offload for future wireless networks

The recent proliferation of smartphone-based mobile Internet services has created an extraordinary growth in data traffic over cellular networks. This growth has fostered interest in exploring alternatives to alleviate data congestion while delivering a positive user experience. It is known that a very small number of users and applications cause a big percentage of the traffic load. Hence, adopting smarter traffic management mechanisms is one of the considered alternatives. These mechanisms allow telecom operators to move selected IP data traffic, for instance, between the cellular infrastructure and the WLAN infrastructure, which is considered a key feature in the latest 3GPP and IETF specifications. This article presents and compares two possible approaches to IP flow mobility offloading that are currently being considered by the IETF. The first one is based on extending existing client-based IP mobility solutions to allow flow mobility where the user terminal is fully involved in the mobility process, and the second one is based on extending current network- based IP mobility solutions where the user terminal is not aware of the mobility.

IEEE 802.21 enabled mobile terminals for optimized WLAN/3G handovers: a case study

Wireless LAN hotspots are becoming widely spread. This, combined with the availability of new multi-mode terminals integrating heterogeneous technologies, opens new business opportunities for Mobile Operators. Scenarios in which 3G coverage is complemented by Wireless LAN deployments are becoming available. Therefore all IP based networks are ready to offer a new variety of services across heterogeneous access. However, to achieve this, some aspects still need to be analyzed. In particular, how and when to execute handovers in order to minimize service interruptions and maximize the use of the most appropriate technologies according to users preferences (for example, a user may prefer to use a lower cost technology if available). This paper presents a simulation study of handover performance between 3G and Wireless LAN access networks. The mobile devices are based on the IEEE 802.21 cross layer architecture and use Wireless LAN signal level thresholds as handover criteria.

QoE-based transport optimization for video delivery over next generation cellular networks

Video streaming is considered as one of the most important and challenging applications for next generation cellular networks. Current infrastructures are not prepared to deal with the increasing amount of video traffic. The current Internet, and in particular the mobile Internet, was not designed with video requirements in mind and, as a consequence, its architecture is very inefficient for handling video traffic. Enhancements are needed to cater for improved Quality of Experience (QoE) and improved reliability in a mobile network. In this paper we design a novel dynamic transport architecture for next generation mobile networks adapted to video service requirements. Its main novelty is the transport optimization of video delivery that is achieved through a QoE oriented redesign of networking mechanisms as well as the integration of Content Delivery Networks (CDN) techniques.

Impact of Heterogeneous Network Controlled Handovers on Multi-Mode Mobile Device Design

The availability of multiple technologies, with micro and macro wireless cells, for network access combined with terminals capable of exploiting such diversity in wireless access requires the development of new mechanisms for optimized handover procedures. Appealing solutions should support network controlled handovers through heterogeneous technologies, preferably combined with a cross-layers two/three design. The IEEE 802.21 working group is currently standardizing the methods and the protocol potentially able to provide such a solution. In this paper we analyze the impact of signaling timing on network controlled handovers execution and performance in this environment. Through an extensive simulation study, we obtain results, that can be exploited in both terminal and handover procedure designs.

Toward IP converged heterogeneous mobility: A network controlled approach

Envisioning a future where mobile terminals equipped with one or more network devices are able to roam across wireless or wired networks, in a diverse macro and micro wireless cells environment, requires the development of enhanced methods to control IP-based mobility. These methods should consider traditional terminal mobility (mainly due to user movement) as well as mobility across heterogeneous networks in the presence of semi-static users. For this to become reality, a cross layer interaction is required starting from a potentially large diversity of layer two access technologies up to the common IP layer, allowing the exchange of messages between terminals and network components. Furthermore, traditional host mobility driven concepts need to evolve, and include more stringent mobile operator requirements in context of fully driven network controlled mobility. This paper presents and evaluates a novel framework design, based on the IEEE 802.21 future standard, encompassing network driven as well as host driven mobility. This paper evaluates signalling aspects, algorithm design and performance issues.

The 'pure-IP' Moby Dick 4G architecture

Network operators, service providers and customers are players who have different interests and raise different requirements on the functionality of future mobile communication networks. However, some new capabilities, such as mobility, security, ubiquity and quality are spelled out by all, which means that there exist some fundamental mechanisms which are in fact needed in every network. This paper concentrates on critical elements of the network infrastructure which need to be deployed in 4G networks before services can be offered. In the paper we discuss these elements, and show how they can be combined to satisfy versatile service requirements. Furthermore, the paper shows how to combine these mechanisms of three traditionally quite separate architectures-for Authentication, Authorisation, Accounting and Charging (AAAC), for Mobility (Mobile IP with Fast Handover), and Quality-of-Service (QoS). A technology-independent paging concept is also integrated in this system. The resulting integrated system architecture is general and can be deployed in heterogeneous environments. Our implementation has recently been completed, validated and verified with applications such as data transfer, voice-over-IP, video streaming and real time concurrent gaming. This prototypical implementation incorporates TD-CDMA, 802.11 WLANs and Ethernet, and treats all transmission technologies as physical and data-link layers, while higher-level functions are supported in a uniform way with an all-IPv6-based signalling.

IEEE 802.21: Media independence beyond handover

The IEEE 802.21 standard facilitates media independent handovers by providing higher layer mobility management functions with common service primitives for all technologies. Right after the base specification was published, several voices rose up in the working group advocating to broaden the scope of IEEE 802.21 beyond handovers. This paper aims at updating the reader with the main challenges and functionalities required to create a Media Independence Service Layer, through the analysis of scenarios which are being discussed within the working group: 1) Wireless Coexistence, and 2) Heterogeneous Wireless Multihop Backhaul Networks.

IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation

The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.

Integration of Broadcast Technologies with Heterogeneous Networks - An IEEE 802.21 Centric Approach

In order to integrate broadcast communication technologies like DVB-H and MBMS in a heterogeneous system, different mechanisms have to be developed, both on the mobile user terminal and on the network infrastructure. This paper presents the framework developed in the Daidalos-II (FP6) project for supporting broadcast integration with heterogeneous wireless networks with a focus on the development of a hybrid terminal.