1. 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

2. Motivation General Surveillance Rain Prediction Computation Rain Mapping Multiple 15 dBi directional antennas

3. Motivation Measurement Setup Antenna Orientation Antenna Separation Routing vs. Non-routing Conclusion and Outlook Overview

4. Measurement Setup Link 3 Node 1 Node 2 Wireless 802.11g link, Distance: 157 meters, ESSID=“pair1” Link 1 Node 3 Node 4 Wireless 802.11g link, Distance: 265 meters, ESSID=“pair2” Link 2 2 meters distance between 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

5. 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

6. 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:

7. 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

8. Routing vs. Non-routing

9. 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)