Rate-Control System with Heterogeneous Time-varying Delays in Broadband Satellite Networks

In a broadband satellite communications network, the propagation delays are not only significant, but also variable among users due to their different geographical locations and the problem becomes more severe with increasing data rates. We consider rate control algorithms with user feedback in the form of single bits and formulate analytic fluid flow models composed of first-order delay differential equations. Both single-flow and multi-flow system models are analyzed, with special attention paid to the Mitra-Seery algorithm. The stationary solutions are investigated first. For the fluctuating solutions, their dynamic behavior is analyzed, in terms of amplitude, transient behavior, fairness, and adaptability, etc., analytically and numerically. Especially the effects of heterogeneous time-varying delays are investigated. It is shown that with proper parameter design the system can achieve stabling behavior with close to pointwise proportional fairness among flows.