1. 1 Golden Gate Club Connectivity

2. 2 Studies of Wireless Networks with Realistic Physical Layer Emulation: The ORBIT Test-Bed Facility Funded by NSF NRT project #ANI-0335244 and DARPA IPTO Rutgers, The State University of New Jersey www.winlab.rutgers.edu Contact: Prof. D. Raychaudhuri ray@winlab.rutgers.edu PnP Networks www.pnphome.com Contact: Richard E. Howard reh@pnphome.com

3. 3 Modeling Wireless Networks: The Radio Problem Ethernet Modeling:  All nodes in a subnet receive all packets  Low error rate  Emphasis on collision, routing, congestion,... Wireless Network Modeling  Packet reception depends on complex, changing RF conditions Hidden nodes and range of link qualities Hard to model—non-local, sensitive dependence on environment  Computationally intractable—”Hall of Mirrors” Extra control “knobs”—transmit power, channel, packet length,... High error rates under the best conditions  Conventional network modeling must be done after getting RF right.

4. 4 Blocked Mission Traffic--Weighted Fraction (BloMiT-WeFra) 100% 10% 1% 0. 1% Mission Time (mtime) BloMiT-WeFra H-Hour 100 MPU added in Sector C —local overload Reconfigure network, power/rate management, delay low priority data. 200 MPU leave Sector M —local capacity excess Reconfigure network, power/rate management, send buffered data. Localized bursty radio interference Adjust fragmentation threshold, manage power/data rate. Waterloo Midway A1 B A2 C2 C B A 100 MPU added in Sector C —local overload Localized bursty radio interference C1 Legend Cognitive control (CogCon) Static configuration (SOA) Perfect control

5. 5 ORBIT: Testbed Overview ORBIT consists of radio grid emulator + field trial network Emulator used for detailed protocol evaluations in reproducible complex radio environments Field trial network for further real-world evaluation & application trials Mobile node (robotic control) Static radio node Radio link emulation 1. Radio Grid for Lab Emulation Dual-mode Radio device 2. Field Trial Network “Open” API Access Point (802.11b) End-user devices Ad- hoc link 3G access link High Speed Net Firewall Mobility Server Wired routers Emulator Mapping “Open” API 3G BTS Global Internet ns-2+ scripts & code downloads Research User of Testbed

6. 6 ORBIT: Testbed Facilities Simulation (Cluster)  Compute facility to run simulations (NS)  Create extensions to ns-2 PHY modules for improved realism and cross-layer Emulation Grid  802.11a radio nodes (~20x20 @ 1m spacing)  Mapping of various “typical” wireless net scenarios  Open API for complete flexibility of OS/protocol software; Linux libraries Field Trial System  Outdoor system for greater realism in protocol testing & for application development, live demos, etc.  3G base station router with IP interface  ~50 open API 802.11a AP’s covering RU NB campus, some downtown areas…  Mobile AP’s on buses, etc.

7. 7 ORBIT: Physical Facilities ~12,000 sq ft (Grid + Lab. space + Offices) Rt 1 South @ Technology Center of NJ “Move in” late 2004

8. 8 ORBIT: Radio Grid Scenarios Use programmable, controlled interference in a physically small environment.  An n x m array of identical radios on grid.  A secondary array of programmable interferers Mapping algorithm which matches “real-world” SNR vectors to selected nodes on grid, using some nodes as interferers

9. 9 ORBIT: Field Trial System

10. 10 Interference Measurements Using ORBIT Testbed 1,41,3 1,2 1,12,42,32,22,1 ~3m ~4m ~5m ~1m ~1.5m Link Nodes Interfering Nodes Walls

11. 11 0 12345 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 256 B; 1.0 Mb/sec 512 B; 1.9 Mb/sec 768 B; 2.9 Mb/sec 1024 B; 3.9 Mb/sec 1280 B; 4.8 Mb/sec Packet Loss as a Function of Channel Spacing For Different Packet Payload Sizes Channel Spacing from Interferer Fraction of Dropped Packets PnP-20040524 One sender, 1 receiver, 3 interferers 1 microsecond packet spacing set Packet Payload; Offered Load

12. 12 012345 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Packet Loss as a Function of Channel Spacing For Different Packet Sizes at 1/3 Lower Rate Fraction of Dropped Packets Channel Spacing from Interferer PnP-20040526 One sender, 1 receiver, 3 interferers 100 microsecond packet spacing set, 1 mW 256 B; 0.67 Mb/sec 512 B; 1.35 Mb/sec 768 B; 2.0 Mb/sec 1024 B; 2.7 Mb/sec 1280 B; 3.4 Mb/sec Packet Payload; Offered Load

13. 13 00.511.522.533.5 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 PnP-20040526 One sender, 1 receiver, 3 interferers Packet Loss as a Function of Throughput For Different Channel Spacings Net Throughput (Mb/sec) Fraction of Dropped Packets Same 1 2 3 4 5 Channel Spacing

14. 14 High Power Increases Channel Overlap FNFN FNFN Sending Nodes Receiving Nodes Near Far

15. 15 Optimizing Wireless Networks Ch 1 Ch 2 Ch 10 Ch 5 Video Data Net A Net B Adjacent Channel Interference Both networks have reduced capacity Partition Network Based on Application Requirements Requires Knowledge of Application Behavior Greatest Improvement Video subnet optimized for QOS FNFN

16. 16 Network States (Measured) State BloMIt-WeFr Rate Traffic Rate (kb/sec) 1 One pair of nodes communicating 0.001,350 2 Add 3 pairs of nodes with similar traffic on nearby channel 0.403,240 3 Change new nodes to same channel as original 0.084,960 4 Three nodes leave and traffic rate increased for single link 0.002,700 5 Add 3 pairs of nodes with similar traffic on adjacent channel, higher data rate and longer packets than state (2) 0.891,224 6 Change new nodes to same channel as original 0.406,480 7 Change new nodes to channel 6 as it becomes available (other nodes leave). 0.228,380 8 Same as state (7) with command traffic switched to channel 1 link 0.078,380 9 Three nodes leave and traffic rate increased again for single link by shortening time between packets. 0.003,830 10 Add 3 pairs of nodes with similar traffic on adjacent channel 0.98260 11 Change new nodes to channel 6 as it becomes available (other nodes leave). 0.389,400 12 Same as state (11) with command traffic moved to channel 1 link 0.149,400

17. 17 Integrated Mission IT Metrics-- Static Path Through Mission

18. 18 Integrated Mission IT Metrics-- Optimized Path Through Mission Improvement potential for this mission profile BloMiT-WeFr: 1,578 => 182 Mission Traffic: 14 GB => 62 GB Note: This is wireless link-layer characterization only. Guaranteed delivery protocol (e.g. TCP) would add “thrashing” and increase the difference.