Globally Stable Wireless Data Flow Control

Abstract

Packet data flow control from internet nodes to wireless transmission nodes will become increasingly important in 5G wireless systems. One reason is the new requirement to maintain and guarantee a maximum round-trip loop delay for high-bandwidth feedback control applications. Another driver is the emerging multipoint mobile broadband internet access, where data starvation needs to be avoided in the transmit queue buffers of the wireless transmission nodes. Moreover, robust global stability is a requirement, since an only locally stable data flow controller would have a nonzero likelihood to malfunction algorithmically. The resulting networked control problem is further complicated by an uncertain internet backhaul loop delay, in combination with a one-directional data flow that introduces saturation in the feedback loop. The paper therefore contributes with a proof of global robust stability for a nonlinear networked window-based packet flow control algorithm. The performance and stability of the controller are assessed with simulation, which shows that the algorithm performs as required.