Scheduling policies for an VOD system over CATV networks

Video-on-Demand(VOD) is expected to be the key residential service in the coming decade. Among other solutions, a VOD system based on current Community Antenna TV (CATV) transport network is the most economic, straight forward, and feasible solution. However, current CATV networks, shared by hundreds of thousands of people, can only support hundreds of broadcast channels. Therefore, the VOD system over the CATV network will have a serious problem on bandwidth limitation. We believe that a good scheduling policy can avoid the bandwidth limitation problem by utilizing the broadcast feature of the CATV networks. In this paper, two types of scheduling policies are proposed: batching without queueing policies and batching with queueing policies. We show that for a system of 5000 users with a viewing rate of 2.0 per week and an average waiting time of 10 minutes, batching without queueing policies only reject about 8% of total requests per day. The rejection rate can be further reduced to about 5% by using batching with queueing policies. Finally, We show that the proposed BMN policy is able to schedule movies fairly, in terms of the average waiting time and the percentage of requests rejected per movie.