Enhanced interference cancellation techniques for downlink of LTE-A heterogeneous networks

Abstract

The formation of Heterogeneous Network (HetNet) into the cellular system improves the overall spectral efficiency and network capacity of the system. Although the forming of the heterogeneous cellular network increases the complexity and overall interference of the system, the interference between the macro cell and smaller cells like femto/pico reduces the overall performance of the system in the downlink. In downlink, the Common Reference Signal (CRS) is used at the User Element (UE) to estimate the channel characteristics and is available throughout the entire frequency band. The presence of CRS of the neighbouring cells creates interference to the users. Linear Minimum Mean Square Error (LMMSE) based equaliser is proposed to reduce the effect of the non-colliding CRS at the UE. Enhanced space alternating generalised expectation maximisation-maximum a posteriori probability (ESAGE-MAP) estimator is used at the UE to mitigate colliding CRS interference. The simulation results have proved that the proposed LMMSE and ESAGE-MAP interference cancellation techniques perform better than the existing methods.