  An indoor robot navigation system is investigated, where an intelligent
reflecting surface (IRS) is employed to enhance the connectivity between the
access point (AP) and a mobile robotic user. The considered system is optimized
for minimization of the travelling time/distance of the mobile robotic user
from a given starting point to a predefined final location, while satisfying
constraints on the communication quality. To tackle this problem, a radio map
based approach is proposed to exploit location-dependent channel propagation
knowledge. Specifically, a channel power gain map is constructed, which
characterizes the spatial distribution of the maximum expected effective
channel power gain of the mobile robotic user for the optimal IRS phase shifts.
Based on the obtained channel power gain map, the communication-aware robot
path planing problem is solved as a shortest path problem by exploiting graph
theory. Numerical results show that: 1) Deploying an IRS can significantly
extend the coverage of the AP and reduce the travelling distance of the mobile
robotic user; 2) 2- or 3-bit IRS phase shifters can achieve nearly the same
performance as continuous IRS phase shifters.
