Location-Based Robust Beamforming Design for Cellular-Enabled UAV Communications

Abstract

Cellular communications have been regarded as promising approaches to deliver high-broadband communication links for Unmanned Aerial Vehicles (UAVs), which have been widely deployed to conduct various missions, e.g. precision agriculture, forest monitoring and border patrol. However, the unique features of aerial UAVs including high-altitude manipulation, three-dimension (3D) mobility, and rapid velocity changes, pose challenging issues to realize reliable cellular-enabled UAV communications, especially with the severe inter-cell interference generated by UAVs. To deal with this issue, we propose a novel position-based robust beamforming algorithm through complementarily integrating the navigation information and wireless channel information to improve the performance of cellularenabled UAV communications. Specifically, in order to achieve the optimal beam weight vector, the navigation information of the UAV system is innovatively exploited to predict the changes of Direction-of-arrival (DoA) angle. To fight against the high mobility of UAV operations, an optimization problem is formed by considering the tapered surface of DoA angle and solved to correct the inherent position error. Comprehensive simulation experiments are conducted and the results show that the proposed robust beamforming algorithm could achieve over 90% DoA estimation error reduction and up to 14dB SINR gain compared with five benchmark beamforming algorithms, including Linearly Constrained Minimum Variance (LCMV), Position-based beamforming, Diagonal Loading (DL), Robust Capon Beamforming (RCB) and Robust LCMV algorithm.

Adaptive Diagonal Loading Technique to Improve Direction of Arrival Estimation Accuracy for Linear Antenna Array Sensors

“…Concurrently, the diagonal loading factor, 𝐹, is calculated, which leads to the reformulation of a new diagonally loaded sample covariance matrix, 𝐑 V 𝐱𝐱7𝐃𝐋7𝐌𝐨𝐝 as in (15). Finally, the traced sample covariance matrix, 𝐑 V 𝐱𝐱7𝐃𝐋𝐓 is reformulated for DOA estimation as described in (16). Then, the subspace decomposition of ( 16) can be presented as…”

“…In more recent years, Diagonal Loading (DL) of the sample covariance matrix has been a popular technique to improve DOA estimation efficacy and beamforming capabilities while reducing computational costs in a limited sample situation [15,16]. The DL algorithms can be considered an auxiliary subsystem into the primary DOA technique by correcting all the sample eigenvalues with the same parametric value to increase the resolution for improved beamforming and signal direction selection [17].…”

Passive Sensing Using Multiple Types of Communication Signal Waveforms for Internet-of-Everything

“…In the scenario of low SNR, spatial filtering is used, among which the adaptive method is a highly effective spatial filtering method [28]. To deal with direct wave interference, the Linearly Constrained Minimum Variance (LCMV) algorithm can be used to constrain the direction of the direct wave emitted by the external illuminators [29]. To deal with multipath interference, it is necessary to use a wide-nulling method to produce nulling in the direction of multipath interference for suppression [30].…”

NOMA Enhanced UAV-Assisted Communication System With Nonlinear Energy Harvesting

“…) where P NL Ih and P C are the available transmit power 6 at I u and C u , respectively. h i and h SC are the channel between I u and I i and C u and I i , respectively.…”