  The radio frequency (RF) spectrum becomes overly crowded in some indoor
environments due to the high density of users and bandwidth demands. To
accommodate the tremendous wireless data demands, efficient spectrum-sharing
approaches are highly desired. To this end, this paper introduces a new
spectrum sharing solution for indoor environments based on the usage of a
reconfigurable reflect-array in the middle of the wireless channel. By
optimally controlling the phase shift of each element on the reflect-array, the
useful signals for each transmission pair can be enhanced while the
interferences can be canceled. As a result, multiple wireless users in the same
room can access the same spectrum band at the same time without interfering
each other. Hence, the network capacity can be dramatically increased. To prove
the feasibility of the proposed solution, an experimental testbed is first
developed and evaluated. Then, the effects of the reflect-array on transport
capacity of the indoor wireless networks are investigated. Through experiments,
theoretical deduction, and simulations, this paper demonstrates that
significantly higher spectrum-spatial efficiency can be achieved by using the
smart reflect-array without any modification of the hardware and software in
the users' devices.
