1. PAC: Perceptive Admission Control for Mobile Wireless Networks Ian D. Chakeres Elizabeth M. Belding-Royer

2. Goal Control the amount of traffic in the network Provide high quality service to all admitted traffic Ensure the network congestion point is not reached

3. Background: Impacted area

4. Background: Receiver is also a sender CSR>RID>RxR

5. Background How is RID defined? When two packets are transmitted simultaneously, the signal power of one must be great then another by some capture factor (10) The signal strength of any other transmission can not be greater than RXTresh/10

6. Background The safe distance between two senders is 2RxR+RID

7. Perceptive Admission Control Nodes determine the available bandwidth on their own No query flooding is needed Change the CSR to 2RxR+RID Can determine accurate available bandwidth without sending query messages A sender can detect the possible impact of creating a new traffic

8. Determining the Available Bandwidth MAC Layer Congestion Window Queue Length Number of Collision Delay Channel Busy Time Transmitting Receiving Busy

9. Perceptive Admission Control New CSR A sender can consider only the traffic within this new CSR before admitting a new traffic

10. Contention-Aware Admission Control Protocol (CACP) V.S. PAC

11. Query flooding may fail S2 is an isolated node, but it does affected by the new traffic brought by S1 Solution: use high power packet transmission to send the query message

12. Mobility What would happen if two sender-receiver pairs move closer than the safe range 75% ?

13. Mobility Each source monitors the available bandwidth Senders check available bandwidth after a random time and before sending a packet Random back-off time

14. Simulation Result

16. PAC does not send query message, thus reduce the query overhead.

17. Conclusion PAC effectively limits the amount of data traffic to avoid congestion Provides consistent throughput, low packet loss and delay Useful in wireless application that requires high QoS such as multimedia applications