Proactive earliest due-date scheduling in wireless packet networks

Providing deadline-based scheduling in wireless networks is a challenging problem because the medium suffers from location-dependent errors. In this paper, we propose a new scheduling policy called proactive earliest due-date (PEDD) that proactively modifies the packets´ deadline depending on the upcoming changes in the channel states. This policy gives a higher priority to packets that will see bad channel states so that they can be scheduled before their channels turn bad. Simulation results using OPNET show that our scheme can achieve lower average packet drop ratio and higher average system throughput compared to feasible earliest due-date (FEDD). Although its average system delay is higher, it still provides delay bound guarantee that is vital for scheduling real-time traffic. The performance improvements of PEDD over FEDD will depend on how well the channel knowledge is obtained.