Joint Load Balancing of Radio and Transport Networks in the LTE Systems

Load Balancing (LB) is an important mechanism often used in the cellular networks to offload the excessive traffic from high-load cells (hot spots) to low-load cells. Extensive studies have shown that the system level performance with LB can be greatly enhanced in terms of e.g. higher overall system throughput, lower user blocking ratio and better QoS (Quality of Service) for the users at the cell boundaries. However, so far the conventional LB solutions are mainly focusing on Radio Networks (RN), and little consideration of the impact from Transport Networks (TN) has been taken into account in the LB mechanisms. This paper proposes a joint load balancing framework for the Long Term Evolution system. The proposed LB takes into consideration the joint impact of RN and TN by combining the network-wide utilities to achieve overall network optimizations. In this paper, we suggest different utilities for GBR and nGBR service categories. For each service category, the proposed utilities consider multiple QoS classes with different services (e.g. VoIP, video and FTP) and aim to guarantee their individual QoS requirements. The presented numeric results show that the proposed mechanism can outperform the conventional RN-only LB, especially for the situation that the TN last mile link is the bottleneck and its deploy-ment is heterogeneous.