  The communication at mmWave frequencies is a promising enabler for ultra high
data rates in the next generation of mobile cellular networks (5G). The harsh
propagation environment at such high frequencies, however, demands a dense base
station deployment, which may be infeasible because of the unavailability of
fiber drops to provide wired backhauling. To address this issue, 3GPP has
recently proposed a Study Item on Integrated Access and Backhaul (IAB), i.e.,
on the possibility of providing the wireless backhaul together with the radio
access to the mobile terminals. The design of IAB base stations and networks
introduces new research challenges, especially when considering the demanding
conditions at mmWave frequencies. In this paper we study different path
selection techniques, using a distributed approach, and investigate their
performance in terms of hop count and bottleneck Signal-to-Noise-Ratio (SNR)
using a channel model based on real measurements. We show that there exist
solutions that decrease the number of hops without affecting the bottleneck SNR
and provide guidelines on the design of IAB path selection policies.
