ieee802.11mac層協(xié)議性能分析與優(yōu)化

1、南京郵電大學(xué)碩士學(xué)位論文IEEE802.11MAC層協(xié)議性能分析與優(yōu)化姓名：章杰侈申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：通信與信息系統(tǒng)指導(dǎo)教師：糜正琨2011-03南京郵電大學(xué)碩士研究生學(xué)位論文 ABSTRACT II ABSTRACT In recent years, IEEE 802.11 based WLAN has

2、 been widely used for its convenience, flexibility, low cost and easiness to be extended. However, its performance is expected to be lower than the traditional wireline networks. Although it is regarded as an inherent ch

3、aracteristic of wireless networks, the inefficiencies of Medium Access Control (MAC) protocol also contributes to the performance degradation. As such, it is of importance to make research on the improvement of the perfo

4、rmance of IEEE 802.11 MAC protocol. With the popularity of the IEEE 802.11 standards, many analysis models for the distributed coordination function (DCF) have been proposed. A careful study at backoff counter decrement

5、rules in the specification allows us to conclude that the slot immediately following a successful transmission can be accessed only by the station that has just successfully transmitted in the previous slot time. Thus, t

6、he assumption of uncorrelation and statistical homogeneity between consecutive channel slots is not true generally. The thesis proposes a new DCF analysis model that takes into account such a correlation while being able

7、 to retain the simplicity of typical analysis model. In addition, the thesis proposes a new virtual backoff algorithm (VBA), which is based on the sequencing technique for efficient medium access control. The VBA scheme

8、uses fair distributed mechanisms to access a channel. A counter is introduced at each node to keep the transimission discipline of the nodes. The proposed method minimizes the packet collision probability while reducing

9、the MAC delay. Finally, simulations are performed using NS-2 network simulator. The results have shown that the network performance indexes derived from the new DCF analysis model have higher accurasy than that derived f