Achievable secrecy rate analysis in mmWave ad hoc networks with multi‐array antenna transmission and artificial noise

This paper analyzes the achievable secrecy rate in a millimeter wave (mmWave) ad hoc network with multi‐array antenna transmission in the presence of non‐colluding and colluding eavesdroppers. By exploiting the tools of stochastic geometry, the average achievable secrecy rate is derived, taking into consideration the impact of blockages, directional beamforming, and Nakagami‐m fading. Moreover, a simple yet effective artificial noise transmission (Tx‐AN) technique is applied at the transmitting nodes to enhance the secrecy performance while the channel state information at the desired transmitter is unknown. Numerical and simulation results are presented for the average achievable secrecy rate in the mmWave ad hoc network without and with the Tx‐AN technique. For example, at the high transmit power (>20 dBm), the average achievable secrecy rate with the Tx‐AN technique is up to three times higher than that obtained when the Tx‐AN technique is not used. Furthermore, the results demonstrate the secrecy robustness of the Tx‐AN technique against increasing eavesdroppers' intensity. Finally, the proper power allocation between the message and AN signals that maximizes the average achievable secrecy rate is computed.