To overcome the above challenges in 5G wireless backhaul networks, some potential research directions are summarized to solve these issues:
• Distribution cell architecture and protocols can be explored to forward wireless backhaul traffic in the ultra dense small cell networks.
•Millimeter wave communications are recommended to transmit the massive backhaul traffic in 5G wireless backhaul networks.
• Cooperative small cell groups should be investigated to solve handover issues in small cell networks.
• Highly energy-efficient transmission technologies should be developed to guarantee 5G wireless backhaul networks being deployed in a low-energy-consumption way.