  The third generation partnership project (3GPP) has recently defined two
frequency bands for direct access with satellites, which is a concrete step
toward realizing the anticipated space-air-ground integrated networks. In
addition, given the rapid increase in the numbers of satellites orbiting the
Earth and emerging satellites applications, non-terrestrial networks (NTNs)
might soon need to operate with integrated access and backhaul (IAB), which has
been standardized for terrestrial networks to enable low-cost, flexible and
scalable network densification. Therefore, this work investigates the
performance of satellite IAB, where the same spectrum resources at a low earth
orbit (LEO) satellite are utilized to provide access to a handheld user (UE)
and backhaul via inter-satellite links. The UE is assumed to operate with
frequency division duplex (FDD) as specified by the 3GPP, while both FDD and
time division duplex (TDD) are investigated for backhauling. Our analysis
demonstrate that the interference between access and backhaul links can
significantly affect the performance under TDD backhauling, especially when the
access link comes with a high quality-of-service demands.
