A method for adaptive adjustment of contention window in 802.11e wireless network

Abstract

The invention discloses a self-adaption adjustment method of contention windows in an 802.11e wireless network. A network load state is determined according to a network conflict rate via a wireless access point, and the contention windows are adjusted in a self-adaption mode according to the network load state. If the conflict rate is detected to be greater than a given threshold value, the access probability between an AP of current network load and an site is calculated in a multiplicative decrease mode according to an actual conflict rate value; if the conflict rate is detected to be smaller than or equal to the given threshold value, the access probability adapted for the current network load is calculated in a linear increase mode according to the actual conflict rate value. On this basis, an AP access probability is optimized according to the length of an AP current queue. Finally, the largest contention windows and the smallest contention windows between the AP and the site are respectively calculated according to the relations between the access probability and the contention windows. According to the method, the values of the contention windows can be adjusted in a self-adaption mode on the basis of network load conditions, so that the effective availability of a wireless channel is improved, network throughput is increased, and network delay is reduced.

Description

technical field [0001] The invention relates to a self-adaptive adjustment method of a contention window in an 802.11e wireless network. Background technique [0002] With the continuous development of wireless network technology, wireless local area network based on IEEE802.11 standard has been rapidly and widely used in recent years. However, due to the emergence of various new services, there are higher requirements for network performance, and different services have different requirements in terms of throughput, bandwidth, and delay. Enhanced Distributed Channel Access mechanism (EDCA, Enhanced DistributedChannelAccess) is a QoS support extension carried out by the IEEE802.11e working group on the basis of the DCF mechanism in IEEE802.11. Provide priority support for services and video services. [0003] The EDCAMAC layer adopts the control mechanism of CSMA / CA to provide best-effort service. It can only ensure that each node can access the wireless channel fairly fo...

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Problems solved by technology

Therefore, the asymmetric sensitivity of the TCP congestion control mechanism to the discarding of DATA and ACK packets causes the upstream TCP flow to suppress the downstream TCP flow

Moreover, when there are multiple upstream and downstream streams at the same time, due to the IEEE802.11 protocol on the MAC layer, each wireless node including the AP has the same probability of accessing the channel, which will also cause the probability of sending the upstream stream to be higher than that of the downstream stream, which will aggravate the situation. Inhibition of upstream TCP flow on downstream TCP flow

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