On the Implementation of a Dynamic Direction Modulation System with Vector Modulators

Abstract

Dynamic directional modulation (DDM) has already proven to be an efficient technique to achieve physical layer security in wireless communications. System architectures based on vector modulators provide a flexible framework to implement synthesis methods that allow us to obtain increased security and/or independent multichannel transmissions. However, the implementation of DDM with vector modulators requires an accurate calibration (amplitude and phase) of every component in the RF path. In this contribution, we study the sensitivity of the response of a DDM system based on commercial vector modulators showing how to correct the nonideal behavior of all the components thanks to the flexibility provided by the vector modulator.

Multiport Compact Stacked Patch Antenna With 360° Beam Steering for Generating Dynamic Directional Modulation

“…11 depicts the measured constellations in the observation angle before adding AWGN where it can be deduced that the received signal becomes noisier as PEDM decreases. This aspect was already addressed with simulations in [24], showing that this noise could be eliminated through an accurate calibration (magnitude and phase) of the transmitters return loss. In our case, the board specifications only mention return losses higher than 10 dB and, although they are good enough for a standard application, they can produce an increasingly noisy constellation at φs as the PEDM is reduced in order to achieve a narrower secure beam width.…”