Spatial Hopping in MIMO Systems for Impeded Signal Reception by Multi-Element Eavesdroppers

In multiple-input multiple-output (MIMO) systems employing precoding, knowledge of the precoding matrices used is essential for successful reception. Herein, a method is proposed to reduce the ability of a third-party eavesdropper to successfully receive precoded MIMO signals. Rather than precoding with the exact precoding matrices chosen by the intended receiver, transmission occurs by sequentially precoding using a set of precoding matrices clustered around the chosen precoding matrix. This is shown to significantly degrade eavesdropper reception while maintaining performance for the desired user.