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Tim Ireland, Adam Nyzio, Michael Zink, Jim Kurose
Department of Computer Science
University of Massachusetts Amherst
The Impact of Directional Antenna Orientation, Spacing, and Channel
Separation on Long-distance Multi-hop 802.11g Networks: A Measurement Study
WiNMee’07, April 20th 2007
Motivation
General SurveillanceRain Prediction
ComputationRain Mapping
Multiple 15 dBi directional antennas
• Motivation• Measurement Setup• Antenna Orientation• Antenna Separation• Routing vs. Non-routing• Conclusion and Outlook
Overview
Measurement Setup
Link 3
Node 1 Node 2
Wireless 802.11g link, Distance: 157 meters,
ESSID=“pair1”
Link 1
Node 3 Node 4Wireless 802.11g link, Distance: 265 meters,
ESSID=“pair2”
Link 2
2 meters distancebetween antennas
Node 4
45°
Distance: 172 meters
Node 4
90°
Distance: 197 meters
• Laptops• Proxim 802.11 b/g WLAN• 14.5 dBi Yagi antennas
• TCP-based throughput measurements (Iperf)
• 10 times 30 seconds for each setup
Antenna Orientation
• 10 Mbps increase depending on antenna orientation
• Almost full channel capacity with fully separated channels
• The answer lies in the antenna gain pattern
Antenna Separation
• 8.2 Mbps increase through 2 meters vertical separation
• Throughput increase independent from azimuthal orientation
Top view:
Side view:
Top view:
Side view:
Routing vs. Non-routing
Node 3 Node 4Node 1 Node 2
Link 1 Link 2
Node 3 Node 4Node 1 Node 2
Link 1 Link 2
Conclusions & Future Work• Orientation and separation have significant
impact on throughput• Influence of data handling at the multi-hop node• Antenna beam pattern• Max. throughput for complete channel
separation
• Impact of weather and terrain on link quality• Analysis of MAC layer traces from
measurements• Develop models based on measurement results
CDF
Retransmission Burst
F(x
)