Low-complexity Leakage Minimization Beamforming for Large-scale Multi-user Cell-Free Massive MIMO

We propose a low-complexity beamforming (BF) design for information leakage minimization in multi-user (MU) cell-free massive multiple-input multiple-output (CF-mMIMO) systems. Our approach leverages fractional programming (FP) to reformulate the secrecy rate maximization problem into a tractable difference-of-convex form. To efficiently solve the resulting non-convex problem, we employ the Concave-Convex Procedure (CCP), enabling fast convergence to a local optimum. Simulation results demonstrate that the proposed scheme achieves secrecy rates comparable to state-of-the-art (SotA) methods, while significantly reducing computational complexity and improving convergence speed.