Abstract—In this paper, randomized distributed spacefrequency coding (R-DSFC) scheme is proposed for decentralized wireless relay networks. We consider relay-assisted ARQ to overcome the problem such as transmission failure caused by lack of the knowledge of the number of relays. We analyze the throughput, the maximum achievable diversity order, and the coding gain of the proposed scheme and show that the proposed scheme achieves multipath diversity. Also, we formulate the optimization problem for randomization matrix to maximize the coding gain. Simulation results show that the proposed scheme improves the throughput and the reliability.