Download File - Computer Networks & Information Security
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MAC for Directional Antennas Use of directional antennas can improve performance Existing MAC protocols typically assume omnidirectional antennas [Ko00Infocom] presents a modification of IEEE 802.11 suitable for directional antennas Carrier sense is applied on a per-antenna basis Directional antennas may not be suitable for small devices due to size constraints 306
Capacity and MAC Protocols The MAC protocols such as 802.11 are unable to achieve performance close to theoretical capacity Recent work attempts to improve on this [Rozosvsky01] Distributed a pseudo-random transmission schedule to onehop and two-hop neighbors (pseudo-random schedule can be distributed by distributing a seed) • Transmit state, listen state specified for each slot In each transmit slot, transmission probability is chosen as a function of number of nearby nodes in transmit state 307
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Capacity and MAC Protocols<br />
The MAC protocols such as 802.11 are unable to<br />
achieve performance close to theoretical capacity<br />
Recent work attempts to improve on this<br />
[Rozosvsky01]<br />
Distributed a pseudo-random transmission schedule to onehop<br />
and two-hop neighbors (pseudo-random schedule can<br />
be distributed by distributing a seed)<br />
• Transmit state, listen state specified for each slot<br />
In each transmit slot, transmission probability is chosen as a<br />
function of number of nearby nodes in transmit state<br />
307
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