Joint Optimization of Scheduling and Congestion Control in Communication Networks

In this paper we study congestion control and scheduling in communication networks. In contrast to standard protocol design where there is minimal communication between the scheduling and the congestion control, we argue that there are a number of benefits to jointly optimizing these algorithms, especially in wireless networks. The first benefit of the coordination is that we are able to do effective buffer sizing, even when channel rates are variable. The second benefit is that we can prevent conflict situations where the congestion control and the scheduler both try to assign bandwidth to the flows. The third benefit is that coordination allows us to prove theoretical utility maximization results that are not affected by possible oscillations. In the first part of the paper we discuss in detail why joint optimization of scheduling and congestion control can be beneficial. We then describe algorithms from the literature that accomplish this coordination, first in the context of stationary channel rates, second in the context of adversarially defined channel rates and traffic patterns.