  In this letter, we present an intelligent reflecting surface (IRS) selection
strategy for multiple IRSs aided multiuser multiple-input single-output (MISO)
systems. In particular, we pose the IRS selection problem as a stable matching
problem. A two stage user-IRS assignment algorithm is proposed, where the main
objective is to carry out a stable user-IRS matching, such that the sum rate of
the system is improved. The first stage of the proposed algorithm employs a
well-known Gale Shapley matching designed for the stable marriage problem.
However, due to interference in multiuser systems, the matching obtained after
the first stage may not be stable. To overcome this issue, one-sided (i.e.,
only IRSs) blocking pairs (BPs) are identified in the second stage of the
proposed algorithm, where the BP is a pair of IRSs which are better off after
exchanging their partners. Thus, the second stage validates the stable matching
in the proposed algorithm. Numerical results show that the proposed assignment
achieves better sum rate performance compared to distance-based and random
matching algorithms.
