Abstract
Unmanned aerial vehicles (UAV) have attracted increasing attention in acting as a relay for effectively improving the coverage and data rate of wireless systems, and according to this vision, they will be integrated in the future sixth generation (6G) cellular network. Non-orthogonal multiple access (NOMA) and mmWave band are planned to support ubiquitous connectivity towards a massive number of users in the 6G and Internet of Things (IOT) contexts. Unfortunately, the wireless terrestrial link between the end-users and the base station (BS) can suffer severe blockage conditions. Instead, UAV relaying can establish a line-of-sight (LoS) connection with high probability due to its flying height. The present paper focuses on a multi-UAV network which supports an uplink (UL) NOMA cellular system. In particular, by operating in the mmWave band, hybrid beamforming architecture is adopted. The MUltiple SIgnal Classification (MUSIC) spectral estimation method is considered at the hybrid beamforming to detect the different direction of arrival (DoA) of each UAV. We newly design the sum-rate maximization problem of the UAV-aided NOMA 6G network specifically for the uplink mmWave transmission. Numerical results point out the better behavior obtained by the use of UAV relays and the MUSIC DoA estimation in the Hybrid mmWave beamforming in terms of achievable sum-rate in comparison to UL NOMA connections without the help of a UAV network.
Highlights
The explosive number of devices demands data traffic growth and new radio spectrum resources in future 6G systems and the IoT context
full duplex (FD) relay in mmWave UL for 6G cellular systems; We propose the use of the MUltiple SIgnal Classification (MUSIC) algorithm at the hybrid beamforming to detect the direction of arrival (DoA) estimations for each Unmanned aerial vehicles (UAV) and improve the performance of the UAV-aided
Relays are located in different positions with different spatial directions with respect to the base station (BS), and hybrid mmWave beamforming with MUSIC technique is adopted to derive the different DoAs in order to optimize the achievable uplink sum-rate
Summary
The explosive number of devices demands data traffic growth and new radio spectrum resources in future 6G systems and the IoT context. To the best of our knowledge, this paper is the first contribution that considers jointly (i) the UL mmWave communications, (ii) the hybrid beamforming with DoA estimation based on the MUSIC method and (iii) multiple UAVs acting as an aerial BS to relay NOMA transmissions and, achieve better data rate for users who can suffer severe channel conditions. NOMA cellular system; We propose an optimization procedure in order to maximize the average achievable sum rate of the UL mmWave UAV relay network by taking into accounts LoS obstruction, channel time-varying condition, the DoA information at the hybrid beamforming due to the different spatial directions of UAVs, as well as the requirements in terms of quality of service (QoS) for each user.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
