Inter-Cell Interference Coordination Of Heterogeneous Networks

With mobile communication technology developing and mobile terminals widespread popularity, mobile data traffic is growing at an unprecedented rate rapidly. In order to meet the demand of increasing network capacity, Heterogeneous network technology is introduced by3GPP. Some low-power nodes are deployed in coverage with Macro cells to increase network coverage and improve system capacity. Due to a large number of different types of low-power nodes deploying, interference in the heterogeneous network becomes more complex, in order to solve the interference in the heterogeneous network, Inter-cell interference coordination technology become the focus of current research.Inter-cell interference coordination method for HetNet, mainly divides into frequency domain Inter-cell interference coordination scheme based on carrier aggregation and time-domain interference coordination scheme based on ABS. According to ABS subframe position change or not, the time-domain eICIC can be divided into static eICIC, dynamic eICIC and enhanced dynamic eICIC. And enhanced dynamic eICIC adopted joint decision and multiple CQI feedback, so the performance is superior to the former two. However, enhanced dynamic eICIC scheme also has disadvantage, one is in the protected subframe, Macro basestation do not schedule Macro users, which make Macro basestation resources have not been fully utilized, and results in the decrease of system total throughput. The second is the distributed C-RAN structure’s time delay is long in RAN structure system, enhanced dynamic elCIC suppress interference. In order to solve the above problems, the reduced power centralized dynamic eICIC scheme and distributed eICIC scheme based on joint benefit are put forward.In this paper, reduced power centralized dynamic eICIC scheme is proposed, in the protected subframes, Macro base station reduces transmission power to schedule Macro users. In order to reduce the interference to Pico users, the author puts forward a scheme based on guaranteeing necessary transmission rate of Pico base station cell range expansion user. This method makes Macro users throughput improving, and make interference to Pico users to minimum. In the proposed distributed eICIC scheme based on joint beneift, in order to make optimal state choice for each cell in every moment, when each cell making state choice, the cell not only considers the benefit of itself area, but also considers the impact to the surrounding cells benefit, and the surrounding cells should feedback their benefit to the center cell. Center cell will choose the state as its state, which can make the joint benefit maximize. Simulation results show that the proposed two kinds of scheme can improve system performance significantly.