Inter-Cell Interference Coordination And Resource Allocation For Next Generation Wireless Networks

As a primary technology for the next generation wireless communication system, OFDMA (Orthogonal Frequency Division Multiple Access) supports intra-cell orthogonality and as a consequence, the main interference source is ICI (Inter-Cell Interference). Several methods have been proposed for ICI mitigation including frequency planning for ICI coordination, ICI cancellation, and ICI randomization. The ICI coordination is a hot topic, and can be applied to different broadband services. This technology has a good performance on ICI mitigation. In this thesis, for the ICI problem, ICI coordination technology and efficient resource allocation strategy are studied. We optimized the SFR (Soft Frequency Reuse) scheme, which is a classical ICI coordination scheme and proposed a dynamic resource allocation strategy based on ICI coordination technology. All the schemes are evaluated through system-level simulation, and the major work is reflected as follows:Firstly, the next generation cellular network system level simulation platform for the downlink is built, including 19 cells,57 sectors. SFR scheme are studied based on OFDMA-TDD (Time Division Duplex) frame structure, and the simulation results show that the system performance is improved compared with the classic frequency reuse schemes, such as 1×3×1 and 1×3×3 scheme.Secondly, we optimized SFR scheme on three fields:the frequency and power allocation; resource organization structure and users partition criterion. We determined the rules of primary sub-carriers' radiated power amplification factor a from the perspective of fairness. According to the OFDMA-TDD downlink frame structure, the resource organization structure which is proper for OFDMA ICI coordination is defined. This structure divides the OFDMA symbols into two zones:the Inner Zone and Edge Zone. The two zones provide resources for cell inner users and edge users, respectively. Then, we proposed a users partition criterion combining with distance criterion and SINR (Signal to Interference plus Noise Ratio) criterion. The proposed optimization scheme for SFR is formed when the three fields is combined. With the proposed optimization scheme, the cell coverage, distribution of SINR, the rate of MCS (Modulation and Coding Scheme) and the throughput performance are improved compared with classical SFR scheme.Thirdly, we take account of the optimization scheme for SFR based dynamic resource allocation strategy. SFR can be regarded as a system-level resource allocation, and the user-level resource allocation is also essential requirement. The model and simulation implementation of PF (Proportional Fairness) schedule for OFDMA ICI coordination technology is built. Based on the PF schedule, we proposed an improved user-level dynamic resource allocation strategy combining with SFR optimization. This improved strategy can release more sub-carriers freedom and the multi-user diversity gain can be fully exploited. The system can takes more advantage of anti-multipath of OFDMA. Therefore, the throughput is enhanced. We can conclude that the edge and sector throughput of improved dynamic resource allocation outperformed SFR optimization scheme without schedule and SFR optimization scheme with PF schedule. The simulation results also show that the proposed SFR optimization combining with improved dynamic resource can get much higher throughput than classical ICI coordination scheme, even closer to the 1×3×1 scheme.