A SVD-Based Optimum Algorithm Research for Macro-Femto Cell Interference Coordination

The intra-tier interference in heterogeneous networks becomes more serious when the number of macro-femto cells dramatically increases. Based on the singular value decomposition (SVD) algorithm, this paper proposes an optimized interference alignment (IA) algorithm to improve the macro-femto cell downlink rate. To achieve the largest degrees of freedom (DOF), we adopt the precoding matrix as a powerful tool to mitigate the effect of inter-channel interference (ICI). In comparison with the conventional interference coordination methods, the SVD algorithm is capable of adjusting the coefficients of the precoding matrix with lower complexity. Furthermore, zero-forcing algorithm is also used to combat ICI in this proposed IA algorithm. The numerical results show that ICI can be suppressed effectively and the system performance in terms of throughput and signal-to-interference- plus-noise ratio (SINR) can be improved considerably.