Stability of bandwidth request control based on dual feedback in BWA networks

In order for the base station to respond quickly and efficiently to the uplink bandwidth request in broadband wireless access (BWA) networks using time-division duplex (TDD), a dual feedback control algorithm has recently been proposed. In this algorithm the bandwidth request is adjusted in accordance with both the length of the backlogged queue and the mismatch between packet arrival and service rates. This paper presents a thorough study of the stability of the dual feedback algorithm in both continuous-time and discrete-time domains. It turns out that the stability condition in is necessary but not sufficient to guarantee the stability of its discrete-time implementation.