1. SenseIT: Networking 1 Sensor.com WINS NG Networks Networking Research Review SenseIT PI Meeting October 7-8, 1999 Marina Del Rey Presented to Dr. Sri Kumar DARPA/ITO by Sensor.com

2. SenseIT: Networking 2 Sensor.com Outline Distributed Sensor Requirements –Communication system propagation –RF modem signalling choices –Multihop and scalability –Networking architectures WINS NG Communication and Networking System Advances WINS NG Complete end-to-end system

3. SenseIT: Networking 3 Sensor.com Network e node user server applications node internet mobile node remote user remote user node wireline LAN user Gateway node

4. SenseIT: Networking 4 Sensor.com Network Requirements Nodes: –compact, energy limited sensors –deployed on the surface –deployed in structures Gateways: –wireline links (development) –long range wireless links (tactical) –local user displays Robust, redundant, self-assembled

5. SenseIT: Networking 5 Sensor.com Propagation Communication Energy vs. Range –(Energy required for 1 kb data payload) –Surface-to-Surface –1/R 4 propagation –(BPSK transmission and a required error rate of 10 -6 ) 0.11101001k1000k Distance (m) Energy (Joules) 10k100k 1k 100 10 1 100m 10m 1m 0.1m Gaussian Channel Rayleigh Channel

6. SenseIT: Networking 6 Sensor.com Propagation Communication Energy vs. Range –(Energy required for 1 kb data payload) –Conventional Free- Space systems –1/R 2 Propagation –(BPSK transmission and a required error rate of 10 -6 )

7. SenseIT: Networking 7 Sensor.com Propagation –Ground wave influence –1/R 4 propagation law Measurement –WINS nodes –2.4 GHz band –observe large variation in RSS 2468 1/R 4

8. SenseIT: Networking 8 Sensor.com RF Modem Signalling Choices Simple baseband modem –single frequency –limited power due to FCC compliance constraints –not robust against multiuser interference –limited surface-to- surface link capability –may be ideal for tag systems data

9. SenseIT: Networking 9 Sensor.com RF Modem Signalling Choices Direct sequence modem –FCC compliant –large spreading at high power: robust against multiuser interference –narrow spreading at low power: limited robustness and surface-to-surface link capability –low cost data code

10. SenseIT: Networking 10 Sensor.com Signalling Frequency hop Global commercial trend –Special considerations for short range tactical links –Regulatory compliance met –Multiuser capability –Low power cost associated with high performance and robust operation –Adaptive hopping patterns –Adaptive hopping rate –Robust operation observed in the field - weeks of error free operation Requires acquisition data FS

11. SenseIT: Networking 11 Sensor.com Networking Strategy Master/slave radio architecture –Master defines hopping pattern –Master acquires –Slave follows –WINS NG every node may function in either mode reconfiguration at any time self-assembled Master 1 Slave Master 2

12. SenseIT: Networking 12 Sensor.com Multihop, Scalability, Fault Tolerance Multicluster –aggregation of nodes exploits local area environment constraints –cluster aggregates local area information –clusters support robust diversity of connectivity paths (Nodes/Gateways) –cluster derives summary messages –natural scalability advantages –different clustering at higher layers Master Slave Gateway

13. SenseIT: Networking 13 Sensor.com WINS NG Communication and Networking WINS NG Communication and Networking API Specification Upgrades –Transmitter power control derive further energy advantages from multihop –Received signal strength –Variable hop rate –Hierarchical addressing –Network assembly mobility

14. SenseIT: Networking 14 Sensor.com Complete end-to-end WINS NG System –Node geophone sensor –Gateway (WINS Network) –WINS Server (Telephony) –WINS SQL Server (IP) –Web Access (IP/ASP) –Auto-assembly –Fault tolerance –Example Application: event driven Node to Gateway to Server data transfer WINS NG System e node user server applications node internet mobile node remote user remote user node wireline LAN user Gateway node

15. SenseIT: Networking 15 Sensor.com