Physical Layer Security for Hybrid-ARQ Protocols with Massive Antennas

We consider secure hybrid automatic repeat request (HARQ) protocols for massive multiple-input single-output single-eavesdropper (MISOSE) channels. To improve the secrecy rate, the channel state information (CSI), via a negative acknowledge frame, is estimated for beamforming for the next transmission rounds (TRs). To tackle the intractable optimization problem of exact secrecy throughput (ST), the sufficiently accurate approximations of connection and secrecy outage probabilities (OPs) are derived. An iteratively alternating optimization algorithm is adopted to find the optimal rates parameters and number of TRs for the approximated ST.