VoIP in applications for wireless access

Abstract

Voice over IP (or VoIP) is a common term to refer to the different protocols that are used to transport realtime voice and video and the necessary signaling by means of the Internet Protocol (IP). H.323 is an ITU-T standard for real-time voice and video communication over packet networks. During the past two years it has become the standard on the Internet for VoIP. Another relatively recent alternative example is SIP (Session Initiation Protocol) for establishing multimedia sessions, that has been adopted as an RFC by the IETF. The cost to transmit digital information end-to-end is dropping dramatically, while there has been a tremendous increase in the available bandwidth. Not only has this been true in backbone networks, it has be-come the trend in access networks for both fixed and wireless access. The price/performance of end-user electronics is dropping while, at the same time, there has been a tremendous increase in computational power. As far as personal communication and mobility is concerned, we are in the position to create new applications and services that go far beyond what telephony systems have been concerned with and able to accomplish. One of the main contributing factors is the Internet Protocol, which allows these new applications to benefit from the fact that end-user devices are now able to use multiple services and events over a single access. The result is that we are now able to build new interactive services, which can combine both voice and data simultaneously.