Directional modulation and coding in arrays

Directional modulation (DM), a type of array beamforming that scrambles signals in unwanted transmit directions, is applied to coded signals to examine the security benefit. With coding, there is a pronounced SNR threshold below which no useful information can be recovered. Compared to conventional phased arrays, DM is shown to require a higher SNR to decode a signal in unwanted transmit directions while not requiring any additional SNR gain to recover the signal in the desired transmit direction. An optimization method of solving for array weights and simulated examples are given.