Studies On Interference Management Schemes In Heterogeneous Networks

At the beginning of wireless communication development, the operators aimed to build network with excellent coverage using minimum number of base stations. And there came the Macro Cellular Mobile Telephone System. Then with the number of wireless users running up to billions and the tendency of rapidly rising in the next few years, in order to meet with the urgent requirement of better seamless coverage and higher data transmission rate, LTE-Advanced system has started a promising study item to investigate Heterogeneous Networks (HetNet). HetNet consists of a mix of macrocells, low-power nodes such as femtocells and picocells, which can be an effective way to solve the serious problems in Macro Cellular Networks, such as overload of macrocells and weak coverage in edge areas.Owing to advantages of small size, simple deployment and low cost, picocells are mostly utilized in scenes such as concerts where communication traffic is highly concentrated and edge areas where signals from macrocell are weak. However, in Het-Net with macrocells and picocells, more complicated interference scenario and closer distance between macrocells and picocells can severely degrade the system performance, especially for system capacity and data rate of cell-edge users. Consequently, effective interference management schemes are in great demand to mitigate these interference problems in HetNets. In3GPP standardization process for Het-Net, efficient enhanced Inter-Cell Interference Coordination (eICIC) schemes are proposed, such as the time/frequency domain eICIC technologies. In this paper, we pay attention to the investigation of interference management schemes in Macrocell-Picocell HetNet. By giving a detail summarization of networking models in HetNets, we analyze the main interference causes in different HetNet scenarios. Then we concentrate on three promising interference management schemes in HetNet with macrocells and outdoor picocells, that is, Almost Blank Subframe (ABS) scheme, Low Power ABS (LP-ABS) scheme and CoMP-MU-MIMO joint schme with SLNR precoding technology.Based on the dynamic system level simulation platform of HetNet in LTE-A system, we evaluate the improvement degree of system performance brought by three interference management schemes mentioned above. Referring to the simulation results, we also summarize the optimized parameters configuration and suitable HetNet scenes for each interference management scheme. Simulation data and conclusions in this paper can provide necessary technical support for the future heterogeneous network planning and optimization, which is also valuable for operators on actual network.