On achieving profit in providing near video-on-demand services

In near video-on-demand, requests for the same movie arriving within a period of time are grouped together (i.e., batched) and served with a single multicast stream; thereby reducing the bandwidth requirement compared with the unbatched case. We consider here that the use of a multicast channel comes with a cost. Since delayed users may cancel their requests while being batched, this uncollected revenue has to be appropriately balanced with the channel usage cost in order to achieve maximum profit. We address profit issues for a number of batching schemes. In the window-based schemes, users are batched for a fixed period of time before they are served; in the batch-size based scheme, users are served once a certain number of them are collected. We study the system profit in terms of user reneging behavior, movie popularity, and multicast channel cost. By combining the advantages of the window-based and the batch-size based schemes, we introduce a scheme which adapts to the fluctuating request rate to achieve high profit