An Inter-Cell Interference Coordination Scheme Based On Virtual Hierarchical Cell Structure

The 3GPP Long Term Evolution (LTE) is in the process of standardization for the next-generation mobile communication networks. Orthogonal frequency division multiple access (OFDMA) and multiple-input multiple-output (MIMO) technologies have been proposed for the LTE system in order to cope with multipath fading and interference impairments. As different orthogonal sub-carriers bear the user information in OFDMA, the base station suffers limited intra-cell interference. Thus, the major interferences come from other cells. The users at the edge of a cell suffer more serious interference from the neighbor cells. Therefore, it will decrease the overall throughput of the cell with OFDMA technology when all cells share the same frequency band. Additionally, the users at the cell edge will be served with poor quality, and the throughput at the cell edge will also decrease.3 GPP LTE proposed inter-cell interference coordination (ICIC) technique to limiting the inter-cell interference. The core idea of this technique is to achieve an efficient management means for the available sub-carrier resources in the cells. By means of restricting frequency resources to different groups, the interference to the neighbor cell will be restrained; in addition, it will have enhancements on carrier-interference ratio (CIR), throughput and coverage at the cell edge. However, the existing interference coordination schemes have low spectrum utilization at cell edge and have a poor support to high-speed users.Therefore, a inter-cell interference coordination scheme based on virtual hierarchical cell structure (V-HCS) is proposed in this paper. The new scheme is composed of two layers interference coordination scheme. One layer is the interference coordination scheme for low-speed users, while the other layer is the interference coordination scheme for high-speed users. It is used in order to improve the cell edge spectrum utilization and the overall OFDMA system performance for users with high moving speed. this paper designs and completes the LTE ICIC system level simulation platform. Based on the platform, the new ICIC scheme performance is evaluated by simulation analysis. The simulation results shows that the new scheme can improve throughput at the cell edge and reduce the resource reallocation times, enhance the performance of the system.