Heuristic optimizing of PCI assignment in real-life LTE networks

Assignment of Physical Cell Identity (PCI) is an important work in TD-LTE network optimization, and the reasonable PCI allocation helps to eliminate the interference and improve the quality of service of networks. In the practical large-scale TD-LTE networks, how to properly reuse PCIs among a large number of cells is challenging. In this paper, we propose a multiobjective optimization model for PCI allocation. This model aims to minimize both the interference and the number of the cell pairs violating soft constraints while maintaining the hard constraints being satisfied. We present a heuristic solution to this optimization model. This heuristic scheme uses the maximum spanning tree to determine the eNodeB order, and then following this order, assigns the available PCIs to each eNodeB´s cells in a step-by-step manner. We applied the heuristic scheme to adjust the PCI configuration of 1233 cells in the real-life TD-LTE network in Zhuhai city, Guangdong Province, China. From the interference and constraint viewpoints, the optimized PCI configuration is evaluated and compared with the original configuration. The evaluation results demonstrate that the proposed heuristic scheme considers several constraints and is an efficient approach to PCI optimization in large-scale and real-life TD-LTE networks.