Lightweight Retransmission for Random Access in Satellite Networks

Existing random access protocols designed for satellite networks have poor performance in short burst communications because of the difficulty on global time synchronization and frequent collisions. In this paper, we propose a Lightweight Retransmission (LwR) mechanism for random access in satellite networks to reduce collisions and get rid of synchronization requirement. In our LwR, only partial bits in a packet are retransmitted. Firstly, we formulate the lightweight retransmission problem and prove that it is NP-hard. Next, we focus on the construction of partial replicas, which is the core of our LwR, and propose regular and random construction methods. Especially, we prove the sufficient conditions for successfully decoding two conflicted packets by ZigZag. Finally, we propose an algebraic model and derive the upper and lower bounds of successfully decoding probability under different construction methods. Both theoretical analysis and experimental results reveal that the random construction method achieves higher decoding probability than the regular construction method. Simulation results also demonstrate that our LwR significantly outperforms related schemes designed for satellite networks.