A channel-aware scheduler with feedback implosion suppression in reliable multicast data transmission over geostationary satellite networks

In this paper, we propose a channel-aware scheduling algorithm and feedback implosion suppression (FIS) technique that exploits reported Channel State Information (CSI) through the return link from a subset of users in a multicast group for reliable multicast delivery over a geostationary satellite network. Reliability is guaranteed via a MFTP-like transport protocol that retransmits lost segments to the group. The deployed scheduling mechanism uses CSI collected from group members before making a decision as to whether or not to transmit a data segment in the forward link. As such, the algorithm aims at avoiding unfavourable channel conditions to reduce the forward link resources that would be wasted in retransmission. However, the users' feedback collected from a large pool would result in the feedback implosion problem. Hence, we propose a FIS technique to complement the CSI collection policy to reduce traffic implosion in the return link as well as reducing the probability to transmit unnecessary CSI values. A change detection scheme run at the users' terminal is implemented using rectangular sliding test window to update a smoothed CSI value depending on its discrepancies with a nominal model from a reference window. The scheduling algorithm together with the CSI collection and FIS policies aims to reduce file transfer delay (FTD) by trading off total number of CSI updates in the face of L-band mobile satellite channel conditions. © 2007 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved