On secrecy outage of MISO SWIPT systems in the presence of imperfect CSI

In this work, a multiple-input single-output (MISO) simultaneous wireless information and power transfer (SWIPT) system including one base station (BS) equipped with multiple antennas, one desired single-antenna information receiver (IR) and N (N > 1) single-antenna energy-harvesting receivers (ERs) is considered. By considering that the information signal of the desired IR may be eavesdropped by ERs if ERs are malicious, we investigate the secrecy performance of the target MISO SWIPT system when imperfect channel state information (CSI) is available and adopted for transmit antenna selection at the BS. Considering that each eavesdropping link experiences independent not necessarily identically distributed Rayleigh fading, the closed-form expressions for the exact and the asymptotic secrecy outage probability are derived and verified by simulation results.