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 with LB the system level performance can be enhanced in terms of e.g. higher overall system throughput, lower user blocking ratio and better QoS 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. This paper proposes a joint load balancing framework for the LTE (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 an overall network and QoS optimizations. In this paper, both GBR (Guaranteed Bit Rate) and non-GBR traffic are considered. 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 bottleneck and its deployment is heterogeneous.
