1. Influence of Transmission Power on the Performance of Ad Hoc Networks Crystal Jackson SURE 2004

2. Outline Intro Overview of major protocols Model Results Conclusion and Future Work

3. What is an Ad Hoc Wireless Network? Collection of self configuring wireless nodes No infrastructure Simple example:

4. How They Work Multi-hop environment source destination

5. Signal vs. Interference

6. EINR (energy to interference plus noise ratio) EINR = N P O T C P I T c + N o where P O = P T L(d) and P I = ΣP R L(d i ) L(d) = λ (path loss formula) 4πd Received energy Noise Interference i α

7. Major Protocols Slotted time system Channel access protocol  RTS/CTS/DATA/ACK rules B RTS A CTSACK Exactly one RTS received EINR > threshold CTS received EINR > threshold Packet received EINR > threshold Check for ACK RTS CTS DATA ACK 1 Time Slot

8. Major Protocols Network Layer  Queue First in First Out Maximum limit of 50 packets  Routing Dijkstra’s algorithm to calculate routes with fewest relays Radius calculated using EINR threshold Packet Generation  Each node generates a packet in a slot with probability p  Randomly selected destination for packet

9. Model Input File o Number of nodes o Size of the field o Duration of simulation o Spreading factor (value N in EINR calculation) o Generation rate and o Transmission power of a node

10. Model  Nodes placed at random locations  Simulation averaged for 10 trials  Performance measures oCompletion Rate – packets received/packets generated oThroughput – packets received/slot oDelay – slots/packet received oThroughput Efficiency- packets received/unit of energy

11. Results Model o Number of nodes: 100 o Area: 14638m x 14638m o Duration: 30000 time slots o Spreading factor: 128 o Generation rate: 0.001 to 0.030 packets/slot o Frequency: 1 GHz o Transmission power: vary

12. Transmission Powers Used PowerAverage Diameter 1.0W9.9 hops 1.4W8.5 hops 2.2W7.2 hops 7.1W4.9 hops 41.5W3.0 hops Diameter = 2Diameter = 3

13. Completion Rate According to Variations in Transmission Power

14. Throughput According to Variations in Transmission Power

15. Delay According to Variation in Transmission Power

16. Throughput Efficiency According to Variations in Transmission Power

17. Conclusion Higher transmission powers preferred o Advantages o Higher completion rate o Higher throughput o Lower delay o Disadvantage o Lower energy efficiency o Lack of enough power for small devices

18. Future Work Short-term  Varying spreading factor  Packets requiring multiple slots for delivery Long-term  Model with adaptive transmission powers o Low transmission powers for lower generation rates o High transmission powers for higher generation rates

19. Acknowledgements Dr. Russell SURE Coordinators  Dr. Noneaker  Dr. Xu NSF