Design of a Two-Stage Scheduling Scheme for DVB-S2/S2X Satellite Architecture

摘要

One of the main characteristics of the DVB-S2/S2X standard is the capability of using the Adaptive Coding and Modulation (ACM) technique. Differently from Variable Coding and Modulation (VCM), ACM provides a feedback path in the return channel for dynamically varying protection error levels in accordance with different channel conditions. In this article, a double-layer packet scheduling mechanism able to support different QoS levels monitoring the propagation and channel conditions is proposed. It consists of a Two-Stage Scheduler (TSS) approach and proposes two novel schedulers to be used in the first and second stage: an Adaptive Priority-based Scheduling (APS) able to account QoS requirements is proposed for the first stage; an improved version of Proportional Fair queueing (PF) called PF with Padding and Packing (PF-PP), able to select and transmit in the forward link frames in accordance to an appropriate fair policy is designed for the second stage. Performed experiments show an improvement of the overall system performance in terms of packet drop rate, delay jitter, and packets delay.