Cell-level multiplex scheduling to support multimedia applications in real-time channels

A resource reservation mechanism is widely used in multimedia application systems to guarantee quantitatively specified Quality of Services (QoS). A real-time channel, which is one of the network resource reservation mechanisms for the real-time applications introduced by Ferrari and Verma (1990) promises to support the different QoS requirements. When determining the channel bandwidth reservation level, a real-time channel however, takes into account the worst case of real-time traffic's burstiness which in consequence causes a lower channel utilization. In order to improve the utilization for a given real-time channel as well as to support a different level of QoS requirements, we propose a cell multiplexing scheme in a source node. Since the scheduler in a source can easily recognize the behavior of data traffic, the incoming message can be classified into four different types i.e., real-time, multimedia, aperiodic, and non-real-time message. Then the algorithm schedules them based on the Fixed Priority and EDD+ (Earliest Due Date+), which is an extension of the EDD scheduling, and multiplexes these four types of cell. Our simulation study shows that the proposed algorithm considerably reduces the missing ratio of real-time traffic within a given channel bandwidth level, compared to the case where multiplexing is not considered.