[en] We consider a novel hybrid active-passive reconfigurable
intelligent surface (RIS)-assisted unmanned aerial vehicle
(UAV) air-ground communications system. Unlike the conventional
passive RIS, the hybrid RIS is equipped with a few active
elements to not only reflect but also amplify the incident signals
for significant performance improvement. Towards a fairness
design, our goal is to maximize the minimum rate among users
through jointly optimizing the location and power allocation
of the UAV and the RIS reflecting/amplifying coefficients. The
formulated optimization problem is nonconvex and challenging,
which is efficiently solved via block coordinate descend and
successive convex approximation. Our numerical results show
that a hybrid RIS requires only 4 active elements and a power
budget of 0 dBm to achieve an improvement of 52.08% in the
minimum rate, while that achieved by a conventional passive RIS
with the same total number of elements is only 18.06%.
Disciplines :
Computer science
Author, co-author :
Nguyen, Nhan T.
Nguyen, V.-Dinh
Wu, Qingqing
Tölli, Antti
Chatzinotas, Symeon ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > SigCom