  We propose a novel concept of hybrid relay-reflecting intelligent surface
(HR-RIS), in which a single or few elements are deployed with power amplifiers
(PAs) to serve as active relays, while the remaining elements only reflect the
incident signals. The design and optimization of the HR-RIS is formulated in a
spectral efficiency (SE) maximization problem, which is efficiently solved by
the alternating optimization (AO) method. The simulation results show that a
significant improvement in the SE can be attained by the proposed HR-RIS, even
with a limited power budget, with respect to the conventional reconfigurable
intelligent surface (RIS). In particular, the favorable design and deployment
of the HR-RIS are analytically derived and numerically justified.
