On the Competitiveness of On-Line Scheduling of Unit-Length Packets with Hard Deadlines in Slotted Time

It is shown that the competitive factor for online scheduling of unit-length packets with hard deadlines in slotted time is in the interval [0.5, ], where is the inverse of the golden ratio, = ( p 5 1)/2 0.618034. Moreover, any static priority policy, that in each slot schedules a maximum value packet irrespective of deadlines, achieves competitive factor 0.5. Consider on-line scheduling of unit-length packets with hard deadlines by a single server in slotted time. The model considered in this paper consists of a single server with its associated buer. The server multiplexes packets from several real-time input streams into a single output stream. The system is time slotted, and the unit of time is the service time of a packet. Slot k is the time interval from k to k + 1. Packets arrive early during a time slot, are stored in the buer,