Spectral and Energy Efficiency in 5G RANs with IAB Operating in Millimeter Wave Bands

The use of millimeter wave (mmWave) bands in 5G radio access networks (RANs) is an appealing solution to meet high data volume demands. The wide channel bandwidth of mmWave complements the integrated access and backhaul (IAB) technique, helping to ameliorate the challenges of implementing fiber cable backhaul in a dense small cell RAN infrastructure. This work analyzes the capacity, energy consumption, and energy efficiency (EE) of a homogeneous dense small cell RAN using the IAB technique in mmWave frequency bands. The results show that introducing IAB causes the RAN throughput and, hence, EE to degrade significantly. However, the careful application of sleep mode techniques, whereby empty small cells are completely turned off, mitigates the EE degradation. In a high traffic load scenario with 900 users per km
²
the EE increases on average by 3.12-fold with deep sleep modes enabled.