An information theoretic framework for predictive channel reservation in VoIP over GPRS

The wireless telecommunication industry is now slowly shifting its paradigm from traditional, circuit-switched, voice-alone domain to an integrated packet-switched architecture. This will give rise to a variety of new applications, in the same infrastructure, in a cost-efficient way. However, due to the delay and dilemma behind new 3G mobile applications, it is important to use the legacy 2.5G access systems as much as possible, to make the transition smooth. The recent industry-wide trend towards push-to-talk voice services in GPRS networks is a direct consequence of this emerging packet-switch services. In this paper, we propose a packet-switched-based architectural framework for efficient integrated push-to-talk voice (or VoIP) and data services in GPRS using low-bit-rate coding. The prime novelty and advantage of the framework lies in proposing new intelligent, advanced channel reservation techniques to reduce the voice-packet delay. Subsequent use of packet-classification and packet assembly scheme aids in reducing the packet overhead and achieving the voice quality within ITU's recommendations. The mutual effects of data and voice packets over the entire system is analysed using suitable, two-stage performance modelling. It has also been shown that, for voice over IP (VoIP) services, our proposed framework results in more than 50% capacity gain over current GSM system using a silent-detection mechanism. Copyright © 2006 John Wiley & Sons, Ltd.