Robust Piecewise Linear Algorithm for Point-to-Point MIMO Systems

This letter considers a robust linear precoder optimization problem for point-to-point multiple-input multiple-output (MIMO) systems with imperfect channel state information (CSI), subject to a joint power constraint imposed on both sum-power and maximum eigenvalue power. Making use of the piecewise linear property between power allocations and sum-power, we derive a piecewise linear algorithm to obtain the optimal solution. As the optimal solution can be expressed analytically in terms of at most 2M candidates (M is the number of transmit antennas) whose expressions are all in closed forms, the proposed method can provide an exact closed-form solution.