Cooperation of heterogeneous wireless networks in end-to-end congestion control for QoS provisioning

Sharing radio resources of multiple wireless networks with overlapped coverage areas has a potential of improving the transmission throughput. However, the improvement cannot be achieved in congestion scenarios using independent congestion control procedures among the end-to-end paths. Although various network characteristics make the congestion control complex, this variety can be useful for congestion avoidance if the networks cooperate with each other. In this way, the traffic can be shifted from a congested network to non-congested ones, and the overall transmission throughput does not degrade in a congestion scenario. In this paper, first, a cooperative congestion control algorithm is proposed in which the state of an end-to-end path is provided at the destination terminal by measuring the queuing delay and estimating the congestion level. Second, the decision on when to start/stop cooperation is determined based on the network characteristics, instantaneous traffic condition, and requested quality of service (QoS). Simulation results demonstrate the throughput improvement of the proposed scheme over non-cooperative congestion control.