Small‐gain theorem and finite‐frequency analysis of TCP/AQM system with time varying delay

Abstract

In this study, for the first time, a stabilisation criterion is derived for the TCP/AQM system with time‐varying delay and finite‐frequency (FF) specifications. Two important results are established. The first one shows that the TCP/AQM system operates on a frequency domain. The second one introduces a new model transformation of linear systems with time‐varying delay. The objective is to alleviate the impact that buffering has on latency‐sensitive traffic while preserving bulk throughput performance. Standing on the new model transformation, the scaled small‐gain theorem and the theory, the authors suggest new conditions expressed in terms of linear matrix inequalities for designing powerful Active Queue Management. Finally, the engineering relevance of the theory has been evaluated with different realistic scenarios in NS3 and shows that FFAQM scheme provides the best quality of service.