Integration of 1 Gb/s WLAN in cellular mobile networks

Responsible:

Alcatel SEL AG
Forschungszentrum Stuttgart
z. Hd. Ulrich Barth
Holderäckerstr. 35
D-70499 Stuttgart

The Objectives:

Alcatel's goal in WIGWAM is to develop solutions for the integration of new air interface technologies into cellular mobile communication systems in the sense of an evolution towards heterogeneous beyond 3G mobile communication networks. The vision is to combine the specific advantages of cellular communication systems with that of short range high data rate air interfaces in a very tight way.

Advantages:

A typical topology for the so-called public access scenario is indicated in the graph below. Single hot spots cells or hot spot cell clusters are located at special locations under a cellular overlay net. Such special locations could be e.g. highly populated public areas like central places in towns, meeting facilities, shopping centres, subway stations or street crossings.

Such a heterogeneous mobile communication system shall offer to the mobile user always the best choice of the air interface technology. It shall support omnipresent availability for a large variety of services and best suited access to high data rate demanding applications in special hot spot environments. An improved mobility management will allow for most applications service continuation in situations when the mobile user e.g. leaves the hot spot area. This shall be provided by a so-called seamless or lossless handover to the overlaying cellular net. Moreover, for high bit rate demanding applications, adaptive mechanisms can allow in such a situation in many cases to adapt to the available bit rates within the net and thus avoid also service interruption.

Key research activities:

The two major key research activities addressed in WIGWAM refer to a generic multistandard radio resource management MxRRM and to an enhanced mobility support, both addressing architectural concepts, functional models, interfaces and related protocols.

The multistandard resource management MxRRM aims for providing the best suited air interface to the mobile user with respect to the quality of service QoS required by the application and a most effective usage of the air interfaces. Key points are:

monitoring of available neighbour cells in a heterogeneous multistandard network environment
metrics and measurement sizes for prediction and tracking of the channel quality like bit error rates, received signal strength and signal to interference ratio
actual cell load situation for load balancing and QoS

The enhanced mobility management will provide mechanisms to support mobility in an heterogeneous beyond 3G mobile communication system. Key points are:

mechanisms for seamless and lossless handover required e.g. for multimedia and realtime services
mechanisms for the so-called horizontal handover between cells providing the same radio and access technology as well as for the so-called vertical handover between cells of different technologies
traffic management and routing suitable for the envisaged high data rates

The mechanisms will be as far as possible generic and IP based taking into account the interaction between IP based mobility protocols and conventional mobility mechanisms in cellular networks. The solutions will be tailored to a network side based handover decision and resource allocation. This approach allows to consider the QoS requirements of the applications, the environment and movement of the user as well as the cell load situation in an optimum way.

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