Achievable rate of UAV-based communication with uniform circular arrays in Ricean fading

Abstract In future wireless communication systems, combining unmanned aerial vehicles (UAVs) with massive MIMO technology is a promising solution to meet ever-increasing data demand due to it has advantages of high reliability, cost effective, and flexible deployment. In this paper, we study the achievable rate of UAV-based communication under Ricean fading, where the transceivers of UAV is equipped with circular antenna array (UCA) configuration. We exploit an effective statistical-eigenmode space division multiple-access transmission (SE-SDMA) scheme with only the knowledge of the CSI at the UAV’s transceivers. An exact expression on the achievable rate of UAV-based communication systems with UCA configuration is derived, in which the transceivers utilizes the channel response vector as the beamforming precoder. Based on the derived theoretical results, we gain the relationships of the achievable SE and the system parameters, such that the achievable sum-rate tends to a saturation value in the high signal-to-noise ratio regime. In addition, we find that the high Ricean K -factor and the small values of inner product between different statistical channel vector are contribute to the achievable sum-rate of the UAV-based communication system.