Artificial-Noise-Aided Zero-Forcing Synthesis Approach for Secure Multi-Beam Directional Modulation

Great attention has been paid to wireless communication security in recent years. Directional modulation (DM) is one of the promising secure wireless communication techniques. Multi-beam DM has the capability of sending multiple data streams to cooperative users in different desired directions while distorting signal constellations in all other directions. Dynamic multi-beam DM has been proven to be more secure in real communication scenarios. However, previous synthesis approaches for dynamic multi-beam DM are relatively complex and demand a lot of computations. Therefore, an artificial-noise-aided zero-forcing synthesis approach is proposed. The calculation process of the baseband-weighted vector is simplified using the zero-forcing method, which is closely related to the concept of pseudo-inverse. The dynamic property of multi-beam DM is achieved by randomly changing the artificial noise vector. Compared with previous classical dynamic multi-beam DM synthesis approaches, the proposed approach is more efficient and easier to implement in practical systems with tolerable performance loss.