Systematic design of network coding-aware buffering strategies

The bandwidth sparing capability of network coding for the two-way relay channel has been illustrated by a recent demonstration of this technique for satellite communications. One of the issues that limits the efficiency of network coding in this setting is the difference between the instantaneous bit rates and packet lengths of the streams that converge from the ground terminals to the satellite, which can lead to significant performance degradation due to zero-padding. This problem can be reduced by introducing a buffer at the intermediate node that will aggregate packets from each flow before combining them. However, the design of such buffering strategies has been performed by means of heuristics or has been limited to very specific settings. In this paper, we propose a systematic approach for the analysis and design of buffering strategies for the two-way relay channel considering streams with Poisson arrivals of packets and randomly distributed packet lengths. A system optimization is performed in terms of jitter and spared bandwidth.