Directional Modulation for Compact Devices

Abstract

Abstract-A new directional modulation system which uses radiation pattern data for modulation encoding is proposed. The approach allows compact multiport antennas (e.g. MIMO capable antennas) to be used for directional modulation, replacing extensive arrays. The modulation weighting coefficients are calculated with a fixed, antenna specific equation, thus reducing computational complexity. The solution is intended to enhance privacy in small, battery-operated wireless devices, required for "Internet of Things" applications.

Accurate and Efficient Evaluation of Bit Error Rate for Dynamic Directional Modulation for Standard Modulation Schemes

“…Regarding the feeding networks, we can distinguish between those that use switches [10,13], phase shifters [11,12,20,31], phase shifters with switches [17,21,29], vector modulators (reconfigurable amplitude and phase) [18,19,[22][23][24][25][26]30,32], IQ data separately encoded transmitters [14,27], retrodirective array [28] and a Fourier Rotman lens [15,16]. Some of the reported architectures [14][15][16]27,28] do not require a synthesis method for the antenna weights since the feeding network generates DM straightforwardly. Among the reported synthesis methods, we can find some that make use of brute force and explore all the possible combinations allowed by the architecture by searching for those that generate the desired constellation in the secure direction [10,13,20].…”

“…In some cases [11][12][13]18], the evaluation of BER is carried out, for every observation angle, using approximations that only apply to quadrature phase shift keying (QPSK) modulation and zero-mean artificial orthogonal Gaussian noise. However, most of the evaluation techniques [10][11][12][13][14][15][16][17][18][19][21][22][23][24][25][26][27][28][29][30][31][32] use the time-consuming transmission of a stream of 10 6 -10 7 symbols in a channel with additive white Gaussian noise (AWGN), since it can be applied to SDM and DDM with zero-mean artificial orthogonal noise.…”

Spherical Modes Driven Directional Modulation With a Compact MIMO Antenna

“…To address the size-constraints in IoT scenarios, few works have investigated DM using compact multimodal antennas, e.g. : in [13], a dual-mode antenna of λ/2 diameter is proposed for DM; in [14], a four-mode antenna of 0.7λ diameter is presented for dynamic DM; in [15], a five-mode antenna of 0.65λ is proposed for DM in onbody IoT devices. However, in those works either a relatively large size/profile is still used (limiting their implementation for small IoT scenarios), high side-lobes are present (which can be exploited by eavesdroppers to retrieve the transmitted information), experimental verifications are not discussed, or a model highlighting the complete theoretical framework for synthesizing different beam patterns around the azimuth plane, for a given antenna space, is not presented.…”

Recent advances on physical layer security for wireless communications

“…• Other Methods: we can briefly mention other realizations of DM schemes, like the work in [75] for low power Internet-of-Things (IoT) applications. DM for spread spectrum was studied in [85,86], and the demonstration of a Fourier-Rotman lenses for DM applications in [87] 3.…”