A Retransmission Strategy for Real-Time Streaming over Satellite in Blockage with Long Memory
Abstract
The channel for 8 Comm-on-the-move (COTM) terminal in a blockage environment communicating over a satellite can be characterized as a packet erasure channel with long channel memory and long feedback delay. The goal of our research is to enable real-time application, such as a two-way voice call, over such a challenging channel. These packets need to be delivered reliably with strict order requirement. While various ARQ techniques are often used for this purpose, they become ineffective when the channel is severely blocked with long memory and long feedback delay, and the user desires delay performance that is only a small amount above the physical limit of the channel while not consuming too much bandwidth. We propose a simple periodic retransmit solution for this problem. For example, for a 50% blocked channel with the round trip time being about the same as the channel memory duration, we can achieve average packet delay that is less than one channel memory duration over the minimum possible, while being more than 50% efficient with the bandwidth consumed. For this simple periodic retransmit scheme, we analyze the expected delay of a packet, and compute the difference from the best possible delay. We evaluate the bandwidth consumption and show a delay-throughput tradeoff. We also suggest rules for selecting operating points that balances delay and throughput. Furthermore, we characterize user perception metrics of expected duration and frequency of playback interruptions. Simulations are used to validate the analysis.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 12, 2011
- Accession Number
- ADA570525
Entities
People
- Gregor W. Wornell
- Huan Yao
- Yuval Kochman
Organizations
- Massachusetts Institute of Technology