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The establishment of a typical 3G videotelephony (video calls) session is a process that lasts typically around 5 to 8 seconds between today's deployed 3G video-call enabled terminals. This delay is exclusive of call signalling, and is due to the need to complete several protocol procedures as prescribed by the ITU-T H.324 standard and its annex C, including mobile level detection and H.245 messaging to open logical channels and define multiplexing modes. This paper presents AnswerFast Plus (AF+), a technique that significantly accelerates the 3G videotelephony session setup to make it almost as fast as voice calls (1 second or less). AF+ establishes a video telephony session in a Â½ round-trip duration of information transmission on the bearer channel, which is the minimum that can be achieved, while maintaining the flexibility of exchanging terminal preferences. AF+ offers major benefits not only from a user experience point of view, but also in terms of minimising infrastructure overheads, and reducing subscribers billing concerns. Another important advantage of AF+ is its interworking with deployed handsets. Because it is a 3G circuit-switched bearer based technology, and because AF+ information appears as noise to terminals that do not support it, it has an unmatched interworking record with existing deployed terminals. Extensive experiments on live 3G networks in a number of countries have been conducted and confirm our claims.
3G and Beyond, 2005 6th IEE International Conference on
Date of Conference: 7-9 Nov. 2005