Modular Design for Optimal Cross-Layer Flow Control in CDMA Networks

In this paper, we consider a wideband CDMA network with arbitrary layout and variable MAC-rate assignments, which is connected to a traditional wired IP network. We show that by using an optimization framework, it is possible to construct an overlay system at the MAC and transport layers which regulates rates separately based on the congestion and interference constraints. These rates are coordinated through the addition of an intermediate queue at each wireless source (MAC Queue). With the addition of these intermediate queues and only minor modifications to existing transport layer protocols, a cross-layer optimal rate assignment solution is achieved. Finally, we conduct simulation studies comparing this modular approach with a previously developed cross-layer approach, with a particular interest in delay.