PAC: Perceptive Admission Control
for Mobile Wireless Networks
Ian D. ChakeresElizabeth M. Belding-Royer
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
Background: Impacted area
Background: Receiver is also a sender
CSR>RID>RxR
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
Background
The safe distance between two senders is 2RxR+RID
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
Determining the Available Bandwidth
MAC Layer Congestion Window Queue Length Number of Collision Delay Channel Busy Time
Transmitting Receiving Busy
Perceptive Admission Control
New CSR
A sender can consider only the traffic within this new CSR before admitting a new traffic
Contention-Aware Admission Control Protocol (CACP) V.S. PAC
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
Mobility
What would happen if two sender-receiver pairs move closer than the safe range
75% 75% ?
Mobility
Each source monitors the available bandwidth
Senders check available bandwidth after a random time and before sending a packet
Random back-off time
Simulation Result
Simulation Result
Simulation Result
PAC does not send query message, thus reduce the query overhead.
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
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