The Research Of Inter-cell Interference Coordination Technology Under The Relay Scene In LTE-Advanced System

3GPP organization proposed LTE-Advanced technology which is the evolution of the LTE technology to meet the growing demand for communication services, and to maintain the competitiveness of broadband mobile communications. On the one hand LTE-Advanced system used the OFDM technology, which was the same with LTE system, on the other hand LTE-Advanced system used a variety of new technologies, such as:carrier aggregation technology, enhanced MIMO technology, coordinated multi-point transmission technology (CoMP) and relay technology. The relay technology is used to enhance the communication quality of the cell edge users.To reduce inter-cell interference which caused by the different cell using the same frequencies,3GPP organization proposed a lot of technical solutions, such as inter-cell interference randomization, inter-cell interference cancellation and inter-cell interference coordination. Inter-cell interference coordination technology which has excellent performance in the entire cell throughput, cell edge performance and low complexity has been widely used. The LTE-Advanced system’s architecture will be more complex causing of the using of relay technology, which makes the original Base Station-Terminal two-tier structure into Base station-Relay Station-Terminal three-tier structure. Therefore, the original inter-cell interference coordination technology which applied in the LTE system needed to be changed to adapt to the Relay scene of the LTE-A system. In this paper, the main research is the inter-cell interference coordination techniques in the LTE-A system which used the Relay technology.Firstly, this paper analyzes the inter-cell interference coordination technology which is already used in LTE systems, including Fractional Frequency Reuse (FFR), Soft Frequency Reuse (SFR) and Adaptive Soft Frequency Reuse (ASFR). We simulate these inter-cell interference coordination technology at system-level simulation platform and analysis the pros and cons of these technologies.Secondly, this paper analyzes the impact of the relay technology take for the inter-cell interference coordination technology. Based on above analysis, we proposed a new inter-cell interference coordination strategy which based on the number of users under the scenario of relay. In this strategy, we have designed a new resource allocation method and a new high interference indication (HII). The simulation results show that the proposed strategy improves the average SINR and spectral efficiency (SE) significantly compared with the traditional strategies. The proposed strategy will be more helpful for the applied technology under the scenario of relay.