On the Use of Multiple Amplifiers and Antennas for Efficient Directive Transmission with Large Constellations

In mobile communication wireless systems low interference and robustness against interception are crucial requirements for system reliability and security. For broadband communications, other requirements such as spectral and power efficiency become also important to support the high bit rates and minimize the power consumption of mobile devices. These later ones can be achieved through multilevel modulations and power efficient amplification techniques. Here we present a new approach for the definition of antenna arrays where the directivity is introduced in the transmitted information. Under these conditions the constellation is optimized only for the desired direction otherwise we have a degenerated constellation. Moreover, in this approach multilevel constellations are represented as a sum of BPSK (Bi Phase Shift Keying) components that are amplified independently which allows good power efficiency at the amplification stage despite the high spectral efficiency assured by those constellations. The simulation results presented here show the effectiveness of the proposed approach.