Research Article

On the Optimization of the IEEE 802.11 DCF: A Cross-Layer Perspective

Figure 9

Aggregate throughput of a network with a maximum number of stations equal to 10, transmitting at the fixed bit rate 1 Mbps. Curve represents the maximum link capacity evaluated through (13). The other network parameters are described in the paper. Curves labeled LC region refer to a scenario whereby the contending stations transmit with packet rate  pkt/s. In all the scenarios investigated in the figure, during the time intervals [0,40] s and [80,120] s ten stations contend for the channel, while in the time interval [40,80] s only 5 stations are active. Curves labeled (  pkt/s, BLC region) refer to a scenario whereby the contending stations operate in the BLC region. In this situation, the optimization of the contention window does not improve the aggregate throughput and the two curves are superimposed. In the BLC region, the aggregate throughput can be improved by varying the transmission packet size as emphasized by the curve labeled (  pkt/s, BLC region, ).
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