, STARR 138
SPEAKER: Dr. Enoch Lee, Assistant Professor
Department of Mathematics,
TITLE: Voice over IP (VoIP) over wireless
Intelligent mobile terminals (or users) of next generation wireless networks are expected to initiate voice over IP (VoIP) calls using session set-up protocols like H.323 or SIP (session initiation protocol). To guarantee the service quality of such applications, the call set-up protocol should be robust against network impairments. In this presentation, we analyze the performance of the H.323 call set-up procedure over wireless links using a simple call model under two modes of operations, namely, Regular and Fast Connect. The proposed model assumes the presence of radio link protocol (RLP) and recommends that the VoIP packets be transferred without RLP retransmissions, while H.323 control packets be transferred with RLP retransmissions. The analytical models and details experiments show that the VoIP call set-up performance can undergo significant degradation if RLP is not used at all, even for moderately high frame error rates (FERs) in wireless links. On the other hand, a robust radio link layer, such as RLP, can improve the call set-up delay performance as compared to the existing wireless voice call-set-up delay.
REFRESHMENTS: , STARR 138