Passive optical network based mobile backhaul enabling ultra-low latency for communications among base stations

Low latency is of key importance for mobile networks to support emerging time-critical applications, such as road traffic safety and efficiency. Meanwhile, a passive optical network (PON) is widely recognized as a promising solution for mobile backhaul networks thanks to its high capacity and low energy consumption. In the conventional PON-based mobile backhaul network, where base stations (BSs) are co-located with optical network units, the traffic between the neighboring BSs that are mainly caused by user mobility has to be first sent to the optical line terminal and even further, e.g., edge nodes of mobile core networks, resulting in high latency, although the adjacent BSs are geographically located close to each other. In this paper, a novel PON-based architecture is proposed for mobile backhaul to enhance the connectivity between neighboring BSs. Meanwhile, a tailored medium access control protocol and dynamic bandwidth allocation algorithm are introduced to support fast inter-BS communications. The results reveal that a low latency (less than 1 ms packet delay) for communications among any adjacent BSs can be achieved in the proposed PON-based mobile backhaul network, demonstrating great potential to support future time-critical applications.