A Novel SDMA Uplink Method Based on Time-Modulated Array for UAV Communications

Abstract

In recent years, wireless communications on the unmanned aerial vehicle (UAV) have developed rapidly, in which the airborne antenna array system can be adopted to improve the capacity of the communication systems. However, the application of antenna arrays on the UAV is restricted because they are complex and power-hungry. Since the time modulated array (TMA) is of ability to implement multiple beams with a single RF chain, it has a potential application in wireless communications on the UAV to improve the performance. This manuscript has proposed and verified a novel space division multiple access (SDMA) method based on the TMA, for the uplink of UAV communications. Users in different directions transmit the signals to the UAV with the same carrier frequency, and the TMA on the UAV distinguishes each user’s signal by digital band-pass filters. Numeric simulations are provided to verify the proposed idea, and a simple S-band 8-element TMA is constructed and tested to examine its effectiveness partially.