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Novel Internet applications demand global availability of complex services that can adapt dynamically to application requirements. At the same time, pervasive Internet usage and heterogeneous access technologies impose new challenges for service deployment. We present Spontaneous Virtual Networks (SpoVNet), a methodology that enables easy development of new services with transparent support for mobility, multi-homing, and heterogeneous environments. This article presents the overlay-based architecture of SpoVNet that supports the spontaneous deployment of new services as well as a seamless transition towards future networks. SpoVNet´s architecture offers support for the underlay aware adaptation of overlays by the use of cross-layer information. In the context of two exemplary services like a group communication service and an event service as well as two demanding applications – a realtime online game and a video streaming application – we illustrate how SpoVNet is of value in establishing services and applications for the Next Generation Internet.

Abstract-The complexity of mobile communication systems is permanently increasing. This is due to the introduction and refinement of sophisticated communication mechanisms such as Multiple Input Multiple Output (MIMO), hybrid ARQ, channelaware scheduling, or node cooperation. Many of these mechanisms require detailed multi-cell simulation models for their performance evaluation. This involves computationally extensive models of the wireless multi-path fading channel, which quickly becomes a bottleneck with respect to simulation time. It is therefore of great interest to reduce the amount of computation time spent in the channel calculation. In this paper, we present an attractive approach that offloads the channel computation to a massively parallel but inexpensive NVIDIA graphics card. We discuss the parallel architecture of the resulting simulation system, and study the involved synchronization and communication aspects. We show that the developed system achieves a speed-up factor of about 30 compared to an implementation on regular PC hardware.

Inter-cell interference is a major issue in OFDMA networks. One approach to reduce the amount of interference is to use beam forming antennas. Further interference mitigation is achieved if neighbor base stations coordinate the directions of their beams. This paper presents a novel distributed interference coordination algorithm using main-lobe steering beam formers. Our algorithm does not require any explicit signaling between base stations. Also, it does not require any additional channel measurements to be signaled to the base stations besides those already performed for basic operation. Our evaluations show that significant performance gains can be achieved even with non-greedy traffic.