Opportunistic network coding for secondary users in cognitive radio networks

In this paper, for the first time, we develop an efficient network coding strategy for SUs while considering the uncertain idle durations in CRNs. At its heart is that systematic network coding (SNC) is employed to opportunistically utilize the idle duration left by PUs. To handle the uncertainty of idle durations, we utilize confidential interval estimation to estimate the expected duration for stochastic idle durations, and multi-armed bandits to determine the duration sequentially for non-stochastic idle durations, respectively. Then, we propose a coding parameter selection algorithm for SNC by considering the complicated correlation among the receptions at different receivers. Simulation results show that, our proposed schemes outperform both traditional optimal block-based network coding and non-network coding schemes, and achieve competitive performance compared with the scheme with perfect idle duration information.