Zhenzhen Cao

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Experiments show that IEEE 802.11 DCF system exhibits unstable behavior in the congestion onset load range where the system starts to become saturated. This phenomenon is not well investigated due to the lack of proper models. In this paper, we propose a two-dimensional (2-D) Markov chain model by combining the well-known saturated model with newly(More)
This paper gives a new active queue management algorithm for differentiated service (DiffServ) network, which is based on an new adaptive random early detection (RED) algorithm called pre-estimation RED, so we name it DiffServ PERED. PERED utilizes a short term discrete-time Markov queuing model to estimate the future queue state, then self-adjusts the(More)
Distributed Coordinate Functions (DCF) is the mandatory medium access method for IEEE 802.11 Wireless Local Area Networks (WLANs), which is designed for infrastructure WLANs where all end users connect with Access Point (AP) with single-hop links. DCF doubles its Contention Window (CW) before each retransmission. However, in multi-hops WLANs, a node may(More)
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