Renegotiated CBR transmission in interactive video-on-demand system

An interactive video-on-demand (IVOD) system requires transmission bandwidth allocation for each user. Since the volume of data in each video frame is variable, dynamic bandwidth allocation is desirable. In this paper, a new scheme that dynamically determines required bandwidth based on the queue length at the viewer´s set-top box (STB) is proposed. Although this method is in the renegotiated CBR (constant bit rate) category, it requires no precalculation, so it is easily applied to IVOD. The variance of the video transmission rate for each user is an important factor as it affects the service quality of other multiplexed traffic. It is desirable that the transmission rate is changed gradually. A multi-layer concept is introduced to achieve this. Through numerical evaluation using actual movie data, we demonstrate that the variance of the transmission rate is close to the optimal value and the bandwidth utilization is close to unity.