Optimal Real-time Admission Control Algorithms for the Video-On-Demand (VOD) Service

In order to meet the Quality-Of-Service (QOS) requirements of the VOD (Video-On-Demand) service, and, on the other hand, to maximize the system throughput (revenue), it is essential that the admission control algorithm be carefully designed. In this paper, two new types of admission control schemes for the VOD service are proposed. They are the Enhanced Strict Admission Control (ESAC) and the Probabilistic Admission Control (PAC). In the ESAC schemes, we propose t o use more statistics (of small amount and easily pre-calculated) than the peak frame size of the stored video information to strictly guarantee the QOS requirement and t o achieve potentially much higher throughput. In the PAC schemes, we propose t o use similar statistics as used in the ESAC schemes t o achieve even higher throughput at the cost of some small and controllable likelihood of lost/overdue data. The admission control problems are formulated as feasibility problems where different systems of simultaneous equations are considered. For each admission control scheme, if the corresponding system of simultaneous equations has a feasible solution, then admit the call request; otherwise, reject the call. Special structures of the systems are identified so as to facilitate the development of optimal real-time admission control algorithms. Efficient optimal algorithms are also proposed t o calculate the minimal buffer requirement for a given performance objective.