Distributed Optimization of Local Area Networks - Software Defined Radios - page 125

Ta b l e 7 . 2 The parameters of the IEEE 802.11 MAC protocol

W 15 W 1023

SIFS 16 µs σ 9µs

T preamble 16 µs l ACK 14 bytes

l H 28 bytes

As illustrated in Fig. 7.8 , we assumed that 802.11 Access Points form a hexago-
nal grid. The User Equipments (UEs) are distributed according to a spatial Poisson
point process with a density δ

nodes

=

km 2 . UEs are sending uplink traffic using the
DCF mode. The results for a complete ad-hoc network are similar, but we believe
this topology is a better representation of 802.11 networks today.

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Fig. 7.7 By allowing link 1 to use less defensive T CS , it can increase its throughput. This causes a
throughput drop for link 2. However, as link 1 reduces its power, while sustaining its throughput,
link 2 can support a higher rate due to a decreased interference level