Impact of heterogenous wireless link characteristics on the performance of IP-based group communications

Group communication services in cellular networks have attracted a lot of attention recently and provide an entirely new way of communication in cellular networks. To guarantee acceptable service quality, special focus needs to be put on the impact of heterogenous wireless link qualities within one group of users. In this paper, we propose a light-weight IP-based group communication system, which relies on a network-assisted peer-to-peer architecture. We present results of performance evaluations related to the efficiency of group communication in heterogenous environments (i.e. using different wireless link technologies and operating the system across network boundaries). From the detailed results a "key performance indicator" (KPI) for group communication services is derived, which provides a generic mark to rate a push group-communication system. Furthermore we derive recommendations for the use of floor control mechanisms in situations, where some users within a group are affected by strong link delays