Dear all, Now I'm considering call admission control algorithms for VoIP
over IEEE 802.11 ad hoc networks. However, I have some questions as following:
(1) The traffic model is 64kbps on-off stream for VoIP(i.e., G.711 PCM
codec for VoIP) where the on and off periods are exponentially distributed with
mean 1.5 seconds. Since the total bit rate is 64kbps and there is no packets
generated during off period, therefore the bit rate during the on period is
2*64kbps, thus the sampling rate is 16kHz, However, the bandwidth for voice
signal is no more than 4kHz and the sampling rate 8kHz is enough. What is the
matter? (2) When a call from a station is rejected after the judgements
using the CAC algorithm, the station can not admit itself into the network, How
can I implement the rejecting operation in the ns-2.33 simulation environment?
If the streaming packets are justly discarded, then the packet loss rate is
high. My purpose is completely preventing the rejected station from joining the
network. The above questions may be infant, thank you all very much in
advance! Changchun,
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