A solution to relieve ICI effects on system control information in OFDM-based mobile networks: Conflict coordination on PDCCH via PCI planning

In OFDM-based mobile networks, the full-cell coverage of SCI (System-level Control Information) must be guaranteed for a user that can communicate with its eNB (evolved Node Base station) system. The requirement of SCI coverage causes severe ICI (Inter-Cell Interference) effect. Furthermore, the negative effect is intensified owing to single-frequency networking and physical control region configuration in OFDM-based networks. To enhance the reliability of SCI under the coverage constraint, we investigated how SCI is carried in the Physical Downlink Control Channel (PDCCH) in the common search space, and proposed a solution of Conflict Coordination on PDCCH via PCI (Physical Cell Identifier) Planning (CCP³). In our proposal, PCI planning is used to relieve the ICI effect of the SCI. Thus, a heuristic algorithm is developed for the PCI planning since it is an NP-Complete optimization problem. The link-level simulation experiments and numerical analysis results demonstrate that the proposed CCP³ can improve effective SINR (Signal to Interference plus Noise Ratio) of PDCCH significantly, and reduce RE (Resource Element)-occupation conflict probability of PDCCH around 50%. To the best of our knowledge, this study is the first effort to strengthen the SCI reliability from the view of networking optimization.