Power-Saving Transmission In Mu-Massive-Mimo With Distributed Antennas And Security Guarantee

The physical layer security in a multi-user massive multiple-input multiple-output (MU-Massive-MIMO) system is considered in this paper, where a hidden eavesdropper (Eve) may eavesdrop the information signal of any legitimate user. Two distributed antenna system (DAS) aided power-saving transmit strategies are evaluated: 1) the autonomous full (AF) transmission with explicit artificial noise (AN), and 2) the autonomous DAS (AD) scheme, in which the AN is implicitly generated. Based on the cooperative maximum-ratio transmission and derived closed-form deterministic equivalents of the signal to interference-plus-noise ratios (SINRs) of users and Eve, we minimize the sum transmit power subject to the security constraints on the SINRs. The optimizations in both schemes are complementary geometric programming. In particular, the AD scheme depends on the signal to AN power ratio, which is controlled either by an unified or autonomous multiplicative parameter. In simulations, we illustrate that the sum power consumed in the AD scheme with autonomous parameter is less than the unified case as well as the AF scheme, hence it improves the power-saving in MUMassive-MIMO with security guarantee.